Staring multispectral image sensor based on dual-lens array and manufacturing method thereof

Abstract

The present invention relates to a staring multispectral image sensor based on a dual-lens array and a manufacturing method thereof, comprising: manufacturing a multispectral filter array on the surface of a back-illuminated image sensor; manufacturing a lower microlens array on the lower surface of an optical glass sheet, spin-coating a photosensitive bonding adhesive on the back-illuminated image sensor, and performing a graphical processing to form a pattern corresponding to the lower microlens array; bonding the optical glass sheet and the back-illuminated image sensor together; manufacturing an upper microlens array on the upper surface of the optical glass sheet; and manufacturing a metal electrode. In the present invention, the light intake mode of the image sensor adopts a back-illuminated mode, which has the characteristics of high sensitivity, high film system designability, and high process controllability. The filter is based on the principle of an F‑P standard tool, has a simple structure, and compared with a traditional multispectral imaging system, eliminates a bulky dispersion or interference spectroscopic system. The use of a dual-lens structure can significantly improve the fill factor of the image sensor, increase the duty cycle, and reduce spectral crosstalk.

Description

Technical Field

[0001] The invention belongs to the technical field of staring type multispectral image sensors, and relates to a staring type multispectral image sensor based on a dual-lens array and a manufacturing method thereof. Background Art

[0002] The purpose of multispectral image sensors is to obtain spectral information of various substances by combining spectral recognition technology with imaging technology, so as to achieve the effect of identifying substances. It has the advantages of strong anti-interference ability and high substance recognition accuracy, and can be applied to agriculture, water conservancy, medicine, astronomy, military and other fields. The existing multispectral imaging technology is developing in the direction of high integration, low cost and miniaturization. In these directions, the current mainstream technical solutions include integrating filters on the chip of the image sensor or integrating multispectral filters on the optical window.

[0003] Conventional image sensors are integrated with microlens arrays to increase the duty cycle. However, ordinary microlens arrays will cause changes in the angle of incident light. For on-chip integrated filter solutions, different incident light angles will cause deviations in the optical path of the incident light in the filter, thereby affecting the spectral accuracy. In the solution of integrating multi-spectral filters on the optical window, the microlens array can be integrated on the surface of the image sensor, and the filter exists above the microlens array. However, the incident light passing through the filter will produce multiple reflections between the microlens surface and the filter, causing spectral crosstalk. Other methods are needed to reduce this phenomenon, and it cannot be completely eliminated.

[0004] Therefore, how to reduce spectral crosstalk while increasing the duty cycle is a problem that multispectral image sensors need to solve. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a staring multispectral image sensor based on a dual-lens array and a manufacturing method thereof.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for manufacturing a staring multispectral image sensor based on a dual-lens array comprises the following steps:

[0008] Take a back-illuminated image sensor wafer;

[0009] On a back-illuminated image sensor wafer, a multispectral filter array is fabricated corresponding to each back-illuminated image sensor, wherein the multispectral filter array includes multispectral filters based on the FP etalon principle corresponding to the pixels of the back-illuminated image sensor one by one, and each of the multispectral filters is located directly above the photosensitive area of ​​the corresponding pixel;

[0010] Take an optical glass sheet that matches the size of the back-illuminated image sensor wafer;

[0011] A lower microlens array is fabricated on the lower surface of the optical glass sheet, wherein the lower microlens array comprises a plurality of lower microlenses, the lower microlenses correspond to the multi-spectral filters one by one, and the sizes of the lower microlenses are adapted to the multi-spectral filters;

[0012] Spin coating a photosensitive bonding adhesive on a back-illuminated image sensor;

[0013] Performing patterning on the photosensitive bonding adhesive to form a pattern corresponding to the lower microlens array;

[0014] Each lower microlens is located directly above the multi-spectral filter at a corresponding position, and the optical glass sheet and the back-illuminated image sensor are bonded together and cured at high temperature;

[0015] An upper microlens array is fabricated on the upper surface of the optical glass sheet, wherein the upper microlens array comprises a plurality of upper microlenses, the upper microlenses correspond to the lower microlenses one by one, and the size of the upper microlenses is larger than the size of the lower microlenses;

[0016] The metal electrodes are connected to the corresponding circuit system to form a staring multispectral image sensor.

[0017] Furthermore, the method for making a multi-spectral filter array on the surface of a back-illuminated image sensor is as follows:

[0018] Firstly, a high refractive index material and a low refractive index material are alternately stacked on the surface of the back-illuminated image sensor by electron beam evaporation, ion beam sputtering or reactive magnetron sputtering;

[0019] Then, the alternately stacked high refractive index material and low refractive index material are processed by lift-off or ion beam etching to form a multi-spectral filter at the position just above the photosensitive area of ​​each pixel on the surface of the back-illuminated image sensor.

[0020] Furthermore, the method of patterning the photosensitive bonding adhesive to form a pattern corresponding to the lower microlens array is as follows:

[0021] The bonding adhesive is patterned by photolithography, exposure and development to form a receiving groove at the position of the bonding adhesive corresponding to the lower microlens. The opening size of the receiving groove is adapted to the size of the lower microlens, and the depth of the receiving groove is greater than the height of the lower microlens.

[0022] Furthermore, the method for making a lower microlens array on the lower surface of the optical glass sheet is:

[0023] Firstly, a silicide dielectric layer is deposited on the lower surface of the optical glass sheet by using a chemical vapor deposition method;

[0024] Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the lower surface of the optical glass sheet according to the position of each multi-spectral filter by hot melting of photoresist;

[0025] Then, the deposited silicide dielectric layer on the lower surface of the optical glass sheet is etched by an ion beam etching method to form a lower microlens at the position corresponding to each multi-spectral filter.

[0026] Furthermore, the method for making an upper microlens array on the upper surface of the optical glass sheet is:

[0027] Firstly, a silicide dielectric layer is deposited on the upper surface of the optical glass sheet by using a chemical vapor deposition method;

[0028] Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the upper surface of the optical glass sheet according to the position of each lower microlens by hot melting of photoresist;

[0029] Then, the deposited silicide dielectric layer on the upper surface of the optical glass sheet is etched by an ion beam etching method to form an upper microlens at a position corresponding to the upper part of each lower microlens.

[0030] Furthermore, the silicide dielectric layers deposited on the upper and lower surfaces of the optical glass sheet are silicon dioxide, silicon oxynitride or silicon nitride.

[0031] Furthermore, connecting the metal electrode to the corresponding circuit system includes the following steps:

[0032] The area above the bonding point of the metal electrode is exposed graphically by photolithography;

[0033] An ion beam etching method is used to etch a connection hole above the bonding point;

[0034] A lead wire is connected to the upper end of the pressure welding point so that the lead wire passes through the connection hole and is connected to the corresponding circuit system.

[0035] A staring multispectral image sensor based on a dual lens array comprises a back-illuminated image sensor, a multispectral filter array is arranged on the surface of the back-illuminated image sensor, the multispectral filter array comprises multispectral filters based on the FP standard principle corresponding to the pixels of the back-illuminated image sensor one by one, and each of the multispectral filters is respectively located at a position directly above the photosensitive area of ​​the corresponding pixel; a dual microlens array is also bonded to the surface of the back-illuminated image sensor, the dual microlens array comprises a plurality of dual microlenses for focusing, the dual microlenses are used to focus parallel incident light beams into parallel light with a reduced range, and each of the dual microlenses is respectively located directly above a multispectral filter; a pressure welding point is also arranged on the front side of the back-illuminated image sensor, a connection hole is opened above the pressure welding point, a lead is connected to the upper end of the pressure welding point, and the lead passes through the connection hole and is connected to the corresponding circuit system.

[0036] Further, the dual microlens array comprises an optical glass sheet, a lower microlens array is arranged on the lower end surface of the optical glass sheet, and the lower microlens array comprises a plurality of lower microlenses; the lower microlenses correspond to the multi-spectral filters one by one, and each of the lower microlenses is located directly above the corresponding multi-spectral filter; the size of the lower microlenses is adapted to the multi-spectral filter, and a gap is left between adjacent lower microlenses;

[0037] An upper microlens array is disposed on the upper end surface of the optical glass sheet, and the upper microlens array includes a plurality of upper microlenses; the upper microlenses correspond to the lower microlenses one by one, and each of the upper microlenses is located directly above the corresponding lower microlens; the size of the upper microlenses is larger than that of the lower microlenses, and adjacent upper microlenses are connected to each other;

[0038] The upper microlens is used to focus the incident light inwards and then enter the optical glass sheet, and the lower microlens is used to disperse the light incident from the optical glass sheet outwards to form parallel light and emit it to the multi-spectral filter.

[0039] Furthermore, a bonding glue is provided on the surface of the back-illuminated image sensor, and the dual microlens array is bonded to the back-illuminated image sensor via the bonding glue; the bonding glue is provided with a receiving groove at the position corresponding to each multi-spectral filter, the lower microlens extends into the corresponding receiving groove, and a gap is left between the lower end of the lower microlens and the corresponding multi-spectral filter.

[0040] In the present invention, the light input mode of the image sensor adopts a back-illuminated mode, which has the characteristics of high sensitivity, high film system designability, and high process controllability. The filter is based on the principle of FP standard tool, with a simple structure. Compared with the traditional multi-spectral imaging system, it eliminates the bulky dispersion or interference spectroscopic system. A dual-lens structure is adopted and integrated on the light-entering surface of the multi-spectral image sensor. Compared with other existing multi-spectral image sensors, it can significantly improve the filling factor of the image sensor, improve the duty cycle, and optimize the light response, sensitivity and other parameters of the multi-spectral image sensor. And through the dual-lens structure, the parallel incident light beam can be focused into a smaller parallel incident light, which can reduce the light-entering area without changing the incident angle. The smaller light-entering area can reduce the spectral crosstalk caused by the reflected light, and can also prevent the pixel crosstalk caused by light diffusion, thereby improving the MTF of the device. The dual-lens array is directly bonded to the surface of the image sensor, with low cost, small size and light weight. The dual lens is not made of organic matter, but is made of silicide commonly used in silicon CMOS process, with mature technology and stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0042] Figure 1 The present invention is a flowchart of a preferred embodiment of a method for manufacturing a staring multi-spectral image sensor based on a dual-lens array.

[0043] Figure 2 It is a cross-sectional schematic diagram of a preferred embodiment of a staring multispectral image sensor based on a dual-lens array.

[0044] Figure 3 Schematic diagram of light convergence through a double lens.

[0045] In the figure: 1. back-illuminated image sensor, 2. bonding glue, 3. optical glass sheet, 4-1, 4-2, 4-3, 4-4, 4-5...4-n. photosensitive area of ​​the pixel, 5-1, 5-2, 5-3, 5-4, 5-5...5-n. multi-spectral filter, 6-1, 6-2, 6-3, 6-4, 6-5...6-n. lower microlens, 7-1, 7-2, 7-3, 7-4, 7-5...7-n. upper microlens, 8. solder joint, 21. receiving groove, 81. lead, 82. connecting hole. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0047] like Figure 1 As shown, a preferred embodiment of the method for manufacturing a staring multispectral image sensor based on a dual-lens array of the present invention comprises the following steps:

[0048] S1. Take a back-illuminated image sensor wafer, or use a standard silicon image sensor manufacturing process to make a back-illuminated image sensor 1 on the wafer. Multiple back-illuminated image sensors 1 can be integrated on one wafer, and all back-illuminated image sensors 1 on the same wafer can be made into staring multispectral image sensors at the same time; the following is an example of making a back-illuminated image sensor 1 into a staring multispectral image sensor. The back passivation of the back-illuminated image sensor 1 can be achieved by ion implantation or atomic layer deposition process. The surface film system is simple and mainly plays the role of multispectral imaging. This embodiment uses a back-illuminated image sensor 1 (CCD or CIS) as the basic chip for multispectral imaging, which has high sensitivity; and the dielectric layer on the light incident surface is very simple, which is conducive to the design and manufacture of the filter film system, and has the advantages of high film designability and high process controllability.

[0049] S2, such as Figure 2 As shown, a multispectral filter array is fabricated on the surface of each back-illuminated image sensor 1 on the back-illuminated image sensor wafer, and the multispectral filter array includes multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) based on the FP (Fabry-Perot) etalon principle corresponding to the pixels of the back-illuminated image sensor 1 one by one, and each of the multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) is located directly above the photosensitive area (4-1, 4-2, 4-3, 4-4, 4-5 ... 4-n) of the corresponding pixel. It should be noted that Figure 2 Only the structure of a back-illuminated image sensor 1 after being manufactured into a staring multispectral image sensor is shown, and there are multiple staring multispectral image sensors with the same structure on the back-illuminated image sensor wafer.

[0050] In this embodiment, a multispectral filter array is integrated in situ on the surface of each pixel of the back-illuminated image sensor 1 chip (back side), so as to realize multispectral staring imaging. The multispectral filter is based on the FP standard principle and has a simple structure. Compared with the traditional multispectral imaging system, it eliminates the bulky dispersion or interference spectroscopic system. The method for making a multispectral filter array on the surface of the back-illuminated image sensor 1 is preferably:

[0051] First, high refractive index materials and low refractive index materials are alternately stacked on the surface of the back-illuminated image sensor 1 by electron beam evaporation, ion beam sputtering or reactive magnetron sputtering. By alternately stacking high refractive index materials and low refractive index materials, it is convenient to make a specific wavelength band transparent, thereby achieving the function of filtering. Then, the alternately stacked high refractive index materials and low refractive index materials are processed by stripping or ion beam etching, and a multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5...5-n) is formed at the position directly above the photosensitive area (4-1, 4-2, 4-3, 4-4, 4-5...4-n) of each pixel on the surface of the back-illuminated image sensor 1.

[0052] S3, take an optical glass sheet 3 that matches the size of the back-illuminated image sensor wafer. The optical glass sheet 3 is preferably K9, BK7 or synthetic quartz glass with high transmittance in the visible light band, and the optical glass sheet 3 is used as the support layer of the double lens structure.

[0053] S4. A lower microlens array is fabricated at a position on the lower surface of the optical glass sheet 3 corresponding to the back-illuminated image sensor 1. Since a plurality of back-illuminated image sensors 1 are generally fabricated on a back-illuminated image sensor wafer, a plurality of lower microlens arrays can be fabricated on the lower surface of the optical glass sheet 3 so that the lower microlens arrays correspond one-to-one with the back-illuminated image sensors 1. The lower microlens array includes a plurality of lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n), and the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) correspond one-to-one with the multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), and the sizes of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) are adapted to the multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n). The method for making the lower microlens array on the lower surface of the optical glass sheet 3 is preferably:

[0054] First, a silicide dielectric layer is deposited on the lower surface of the optical glass sheet 3 by chemical vapor deposition. The silicide dielectric layer is usually made of silicon dioxide (SiO 2 ), silicon oxynitride (SiON) or silicon nitride (Si 3 N 4) and other silicides. Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the lower surface of the optical glass sheet 3 according to the position of each multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) by hot melting of photoresist. Then, the deposited silicide dielectric layer on the lower surface of the optical glass sheet 3 is etched by ion beam etching to form a lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) at the position corresponding to each multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n).

[0055] S5, spin-coating a photosensitive bonding adhesive 2 on the back-illuminated image sensor 1. The bonding adhesive 2 is preferably a photosensitive bisbenzocyclobutene (BCB) or polyimide (PI) adhesive, so as to facilitate bonding the image sensor chip and the glass sheet.

[0056] S6, performing a patterning process on the photosensitive bonding adhesive 2 to form a pattern corresponding to the lower microlens array. The specific method is:

[0057] The bonding adhesive 2 is patterned by a photolithography exposure and development method, so that a receiving groove 21 is formed at a position of the bonding adhesive 2 corresponding to the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n), and the opening size of the receiving groove 21 is adapted to the size of the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) so as to accommodate the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n); the depth of the receiving groove 21 is slightly greater than the lower microlens (6 -1, 6-2, 6-3, 6-4, 6-5 ... 6-n), so that a gap can be formed between the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) and the multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), so as to prevent the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) from touching and deforming the multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n).

[0058] S7. Make each lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) located directly above the corresponding multispectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), bond the optical glass sheet 3 and the back-illuminated image sensor 1 together, and cure them at high temperature; the bonding surfaces are respectively the surface of the optical glass sheet 3 with the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) and the surface of the back-illuminated image sensor 1 with the filter.

[0059] S8, making an upper microlens array on the upper surface of the optical glass sheet 3, the upper microlens array comprising a plurality of upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n), the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) corresponding to the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) one by one, and the size of the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) is larger than the size of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n). A double lens array is formed by the optical glass sheet 3, the upper microlens array and the lower microlens array. The method for making the upper microlens array on the upper surface of the optical glass sheet 3 is preferably:

[0060] First, a silicide dielectric layer is deposited on the upper surface of the optical glass sheet 3 by chemical vapor deposition. The silicide dielectric layer is usually made of silicon dioxide (SiO 2 ), silicon oxynitride (SiON) or silicon nitride (Si 3 N 4 ) and other silicides. Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the upper surface of the optical glass sheet 3 according to the position of each lower microlens (6-1, 6-2, 6-3, 6-4, 6-5...6-n) by hot-melting photoresist. Then, the deposited silicide dielectric layer on the upper surface of the optical glass sheet 3 is etched by ion beam etching to form an upper microlens (7-1, 7-2, 7-3, 7-4, 7-5...7-n) at the position directly above each lower microlens (6-1, 6-2, 6-3, 6-4, 6-5...6-n). Figure 3 As shown, the structure of the upper microlens (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) can make the incident light converge to one point, and the structure of the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) can make the converged incident light become parallel light, so that the light can be converged to reduce the light incident area.

[0061] In this embodiment, the dual lens array is manufactured without using organic matter, but is manufactured with silicide commonly used in silicon CMOS technology, which has a mature technology and a stable structure.

[0062] S9, connecting the metal electrodes to the corresponding circuit system to form a staring multi-spectral image sensor. Preferably, the method includes the following steps:

[0063] S91, patterning and exposing the area above the bonding point 8 of the metal electrode by photolithography.

[0064] S92, using an ion beam etching method to etch the optical glass sheet 3, bonding glue 2, silicon and various dielectric layers above the metal electrode's bonding point 8, thereby etching to form a connection hole 82 above the metal electrode's bonding point 8.

[0065] S93, connecting the lead wire 81 to the upper end of the bonding point 8, so that the lead wire 81 passes through the connection hole 82 and is connected to the corresponding circuit system, thereby manufacturing a staring multi-spectral image sensor.

[0066] In this embodiment, the light entry mode of the image sensor adopts a back-illuminated mode, which has the characteristics of high sensitivity, high film designability, and high process controllability. A dual-lens structure is adopted and integrated on the light entry surface of the multi-spectral image sensor (5-1, 5-2, 5-3, 5-4, 5-5...5-n). Compared with other existing multi-spectral image sensors, it can significantly improve the fill factor of the image sensor, improve the duty cycle, and optimize the light response, sensitivity and other parameters of the multi-spectral image sensor. In addition, the dual-lens structure can focus the parallel incident light beam into a smaller parallel incident light, which can reduce the light entry area without changing the incident angle. The smaller light entry area can reduce the spectral crosstalk caused by the reflected light, and can also prevent the pixel crosstalk caused by light diffusion, thereby improving the MTF of the device. The dual-lens array is directly bonded to the surface of the image sensor, with low cost, small size and light weight. The dual lens is not made of organic matter, but is made of silicide commonly used in silicon CMOS process, with mature technology and stable structure.

[0067] like Figure 2As shown, a preferred embodiment of the staring multispectral image sensor based on a dual-lens array of the present invention includes a back-illuminated image sensor 1 manufactured on a wafer, and a multispectral filter array is arranged on the surface of the back-illuminated image sensor 1, and the multispectral filter array includes multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) based on the FP etalon principle corresponding to the pixels of the back-illuminated image sensor 1 one by one, and each of the multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) is respectively located at a position directly above the photosensitive area (4-1, 4-2, 4-3, 4-4, 4-5 ... 4-n) of the corresponding pixel; the multispectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n) are preferably obtained by processing the high refractive index material and the low refractive index material alternately stacked on the surface of the back-illuminated image sensor 1 by the method of stripping or ion beam etching. The surface of the back-illuminated image sensor 1 is also bonded with a dual microlens array. Preferably, a bonding glue 2 is provided on the surface of the back-illuminated image sensor 1. The dual microlens array is bonded to the back-illuminated image sensor 1 through the bonding glue 2. The bonding glue 2 is preferably a photosensitive bis-benzocyclobutene (BCB) or polyimide (PI) type glue, so as to facilitate bonding the image sensor chip and the glass sheet. The dual microlens array includes a plurality of dual microlenses for focusing light. The dual microlenses are used to focus parallel incident light beams into parallel light with a reduced range. Each of the dual microlenses is located directly above a multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5...5-n).

[0068] like Figure 3As shown, the dual microlens array includes an optical glass sheet 3, and the size of the optical glass sheet 3 is preferably adapted to the size of the wafer for manufacturing the back-illuminated image sensor 1, so that the back-illuminated image sensors 1 on the same wafer share one optical glass sheet 3. The optical glass sheet 3 is preferably K9, BK7 or synthetic quartz glass with high transmittance in the visible light band, and the optical glass sheet 3 is used as a supporting layer of the dual lens structure. The lower end surface of the optical glass sheet 3 is provided with a lower microlens array corresponding to the back-illuminated image sensor 1 one by one, and the lower microlens array includes a plurality of lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5...6-n); the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5...6-n) correspond to the multi-spectral filters (5-1, 5-2, 5-3, 5-4, 5-5...5-n) one by one, and each of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) are respectively located directly above the corresponding multi-spectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n); the size of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) is adapted to the multi-spectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), and the adjacent lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n); the bonding glue 2 is provided with a receiving groove 21 at the position corresponding to each multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), and the opening size of the receiving groove 21 is adapted to the size of the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) so as to accommodate the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n); the receiving groove 21 is provided with a receiving groove 21 at the position corresponding to each multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n), and the opening size of the receiving groove 21 is adapted to the size of the lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n); 1 is slightly greater than the height of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n), the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) extend into the corresponding receiving grooves 21, and a gap is left between the lower ends of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) and the corresponding multi-spectral filters (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n).The upper end surface of the optical glass sheet 3 is provided with an upper microlens array, and the upper microlens array includes a plurality of upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n); the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) correspond to the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) one by one, and each of the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) is respectively located at the corresponding lower microlens (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n). 5...6-n); the size of the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5...7-n) is larger than that of the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5...6-n), and the adjacent upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5...7-n) are connected to each other; the upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5...7-n) and the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5...6-n) are usually made of silicon dioxide (SiO 2 ), silicon oxynitride (SiON) or silicon nitride (Si 3 N 4 ) and other silicides. The upper microlenses (7-1, 7-2, 7-3, 7-4, 7-5 ... 7-n) are used to focus the incident light inwards and then enter the optical glass sheet 3, and the lower microlenses (6-1, 6-2, 6-3, 6-4, 6-5 ... 6-n) are used to disperse the light incident from the optical glass sheet 3 outwards to form parallel light and emit it to the multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5 ... 5-n).

[0069] The back-illuminated image sensor 1 is also provided with a metal electrode; the metal electrode includes a bonding pad 8 arranged on the lower end surface of the back-illuminated image sensor 1, a connection hole 82 is provided above the bonding pad 8, a lead 81 is connected to the upper end surface of the bonding pad 8, and one end of the lead 81 passes through the connection hole 82 for electrical connection with the chip.

[0070] In this embodiment, a back-illuminated image sensor 1 is used as a multi-spectral imaging basic chip with high sensitivity. A multi-spectral filter array is integrated in situ on the surface of each pixel on the back of the back-illuminated image sensor chip 1, which is convenient for realizing multi-spectral staring imaging. The dual-lens array can focus the parallel incident light beam into a smaller parallel incident light, and improve the pixel duty cycle without changing the incident angle; the high-transmittance multi-spectral filter (5-1, 5-2, 5-3, 5-4, 5-5...5-n) integrated on the pixel surface has a very low reflectivity, and the smaller light-entry area can reduce the spectral crosstalk caused by the reflected light, and can also prevent the pixel crosstalk caused by light diffusion, thereby improving the MTF of the device.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for manufacturing a staring multispectral image sensor based on a dual-lens array, characterized in that: The following steps are involved: Take a back-illuminated image sensor wafer; On a back-illuminated image sensor wafer, a multispectral filter array is fabricated corresponding to each back-illuminated image sensor, wherein the multispectral filter array includes multispectral filters based on the FP etalon principle corresponding to the pixels of the back-illuminated image sensor one by one, and each of the multispectral filters is located directly above the photosensitive area of ​​the corresponding pixel; Take an optical glass sheet that matches the size of the back-illuminated image sensor wafer; A lower microlens array is fabricated on the lower surface of the optical glass sheet, wherein the lower microlens array comprises a plurality of lower microlenses, the lower microlenses correspond to the multi-spectral filters one by one, and the sizes of the lower microlenses are adapted to the multi-spectral filters; Spin coating a photosensitive bonding adhesive on a back-illuminated image sensor; Performing patterning on the photosensitive bonding adhesive to form a pattern corresponding to the lower microlens array; Each lower microlens is located directly above the multi-spectral filter at a corresponding position, and the optical glass sheet and the back-illuminated image sensor are bonded together and cured at high temperature; An upper microlens array is fabricated on the upper surface of the optical glass sheet, wherein the upper microlens array comprises a plurality of upper microlenses, the upper microlenses correspond to the lower microlenses one by one, and the size of the upper microlenses is larger than the size of the lower microlenses; The metal electrodes are connected to the corresponding circuit system to form a staring multispectral image sensor.

2. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 1, characterized in that: The method of making a multispectral filter array on the surface of a back-illuminated image sensor is: Firstly, a high refractive index material and a low refractive index material are alternately stacked on the surface of the back-illuminated image sensor by electron beam evaporation, ion beam sputtering or reactive magnetron sputtering; Then, the alternately stacked high refractive index material and low refractive index material are processed by lift-off or ion beam etching to form multi-spectral filters at positions just above the photosensitive area of ​​each pixel on the surface of the back-illuminated image sensor.

3. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 1, characterized in that: The method of patterning the photosensitive bonding adhesive to form a pattern corresponding to the lower microlens array is as follows: The bonding adhesive is patterned by photolithography, exposure and development to form a receiving groove at the position of the bonding adhesive corresponding to the lower microlens. The opening size of the receiving groove is adapted to the size of the lower microlens, and the depth of the receiving groove is greater than the height of the lower microlens.

4. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 1, characterized in that: The method for making a lower microlens array on the lower surface of the optical glass sheet is as follows: Firstly, a silicide dielectric layer is deposited on the lower surface of the optical glass sheet by using a chemical vapor deposition method; Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the lower surface of the optical glass sheet according to the position of each multi-spectral filter by hot melting of photoresist; Then, the deposited silicide dielectric layer on the lower surface of the optical glass sheet is etched by an ion beam etching method to form a lower microlens at the position corresponding to each multi-spectral filter.

5. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 4, characterized in that: The method for making an upper microlens array on the upper surface of the optical glass sheet is as follows: Firstly, a silicide dielectric layer is deposited on the upper surface of the optical glass sheet by using a chemical vapor deposition method; Then, a corresponding microlens pattern array is formed on the silicide dielectric layer on the upper surface of the optical glass sheet according to the position of each lower microlens by hot melting of photoresist; Then, the deposited silicide dielectric layer on the upper surface of the optical glass sheet is etched by an ion beam etching method to form an upper microlens at a position corresponding to the upper part of each lower microlens.

6. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 5, characterized in that: The silicide dielectric layers deposited on the upper and lower surfaces of the optical glass sheet are silicon dioxide, silicon oxynitride or silicon nitride.

7. The method for manufacturing a staring multispectral image sensor based on a dual-lens array according to claim 1, characterized in that: Connecting the metal electrodes to the corresponding circuit system includes the following steps: The area above the bonding point of the metal electrode is exposed graphically by photolithography; An ion beam etching method is used to etch a connection hole above the bonding point; A lead wire is connected to the upper end of the pressure welding point so that the lead wire passes through the connection hole and is connected to the corresponding circuit system.

8. A staring multispectral image sensor based on a dual-lens array, characterized in that: It comprises a back-illuminated image sensor, the surface of which is provided with a multi-spectral filter array, the multi-spectral filter array comprises multi-spectral filters based on the FP etalon principle corresponding one-to-one to the pixels of the back-illuminated image sensor, and each of the multi-spectral filters is respectively located at a position directly above the photosensitive area of ​​the corresponding pixel; the surface of the back-illuminated image sensor is also bonded with a dual microlens array, the dual microlens array comprises a plurality of dual microlenses for focusing light, the dual microlenses are used to focus parallel incident light beams into parallel light with a reduced range, and each of the dual microlenses is respectively located directly above a multi-spectral filter; the front side of the back-illuminated image sensor is also provided with a bonding point, a connection hole is opened above the bonding point, a lead is connected to the upper end of the bonding point, the lead passes through the connection hole and is connected to the corresponding circuit system; The dual microlens array comprises an optical glass sheet, a lower microlens array is arranged on the lower end surface of the optical glass sheet, and the lower microlens array comprises a plurality of lower microlenses; the lower microlenses correspond to the multi-spectral filters one by one, and each of the lower microlenses is located directly above the corresponding multi-spectral filter; the size of the lower microlenses is adapted to the multi-spectral filter, and a gap is left between adjacent lower microlenses; An upper microlens array is disposed on the upper end surface of the optical glass sheet, and the upper microlens array includes a plurality of upper microlenses; the upper microlenses correspond to the lower microlenses one by one, and each of the upper microlenses is located directly above the corresponding lower microlens; the size of the upper microlenses is larger than that of the lower microlenses, and adjacent upper microlenses are connected to each other; The upper microlens is used to focus the incident light inwards and then enter the optical glass sheet, and the lower microlens is used to disperse the light incident from the optical glass sheet outwards to form parallel light and emit it to the multi-spectral filter.

9. The staring multispectral image sensor based on a dual-lens array according to claim 8, characterized in that: A bonding glue is provided on the surface of the back-illuminated image sensor, and the dual microlens array is bonded to the back-illuminated image sensor through the bonding glue; the bonding glue is provided with a receiving groove at the position corresponding to each multi-spectral filter, the lower microlens extends into the corresponding receiving groove, and a gap is left between the lower end of the lower microlens and the corresponding multi-spectral filter.

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