Spectrometer based on photoelectric detector array and manufacturing method therefor

Abstract

The present invention relates to the technical field of reconstructive spectrometers. Disclosed are a spectrometer based on a photoelectric detector array and a manufacturing method therefor. The spectrometer comprises a photoelectric detection unit array, the photoelectric detection unit array comprises a plurality of photoelectric detection units, each photoelectric detection unit comprises a photoelectric detector and a dielectric film layer, the photoelectric detector comprises a photosensitive part and an electrode, the dielectric film layer covers the photosensitive part, and the electrode is exposed. The present invention can eliminate the impact of numerical aperture, increase the light receiving area, reduce the optical coupling loss, and achieve simple process.

Description

A spectrometer based on a photodetector array and a manufacturing method thereof Technical Field

[0001] The present invention relates to the technical field of reconstruction spectrometers, and in particular to a spectrometer based on a photoelectric detector array and a manufacturing method thereof. Background Art

[0002] Existing reconstruction spectrometers utilize a technology that separates the filter and photodetector. The photodetector lacks filtering properties and exhibits a relatively uniform response across a wide spectral range. The filter, on the other hand, is a standalone device that is integrated with the photodetector through coupling. To ensure the stability of the filter's spectral characteristics, this technology typically requires a small numerical aperture (NA), which results in significant losses in front-end coupling. Related solutions combining CMOS imaging sensors with multi-filtering thin films essentially separate the filter and photodetector, then transfer the filter film to the CMOS imaging sensor through specialized processes. However, this metasurface filter film imposes extremely high manufacturing requirements, and the transfer process is complex and requires stringent pixel alignment. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a spectrometer based on a photodetector array, which can eliminate the influence of numerical aperture, increase the light receiving area, reduce optical coupling loss, and simplify the process.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A spectrometer includes a photoelectric detection unit array, wherein the photoelectric detection unit array includes a plurality of photoelectric detection units, wherein the photoelectric detection unit includes a photodetector and a dielectric film layer, wherein the photodetector includes a photosensitive part and an electrode, wherein the dielectric film layer covers the photosensitive part and the electrode is exposed.

[0006] The spectrometer of the prior art needs to place a filter in front of the photodetector, and the numerical aperture of the filter is small, and the numerical aperture is closely related to the light collection ability. Therefore, the spectrometer of the prior art is limited by the small numerical aperture of the filter and has to consider the angle of light collection to collect as much light as possible. The technical solution provided by the present invention directly grows the dielectric film layer on the photosensitive part of the photodetector, which is equivalent to directly attaching the filter to the photodetector. All light projected on the dielectric film layer can be absorbed, thereby eliminating the influence of the numerical aperture, increasing the light receiving area, thereby increasing the light collection area, reducing the loss caused by optical coupling, and thus enhancing the luminous flux of the photodetector. Thanks to the inventive concept of the photodetection unit forming an array, the photodetection unit can be flexibly changed according to demand. It only needs to design the corresponding substrate. The production cost and assembly alignment requirements are reduced, the flexibility is increased, and there is no need for multiple mold openings. For example, some applications require that all received light comes from the scattering direction at the same angle as the light source. In this case, the substrate is designed to be circular, and the photodetector array is also arranged in a circular shape to meet the demand.

[0007] Optionally, the dielectric film layer includes multiple layers of transparent media, and there are differences in material and / or thickness between adjacent transparent media.

[0008] Optionally, the transparent medium is provided with at least ten layers, which are replaced alternately.

[0009] Optionally, the material of the transparent medium is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5.

[0010] Optionally, the dielectric film layer has a thickness of 1 μm to 100 μm.

[0011] The technical solution provided by the present invention can achieve the purpose of manufacturing photoelectric detectors with different filtering characteristics by changing the selection of transparent media, setting the number of layers, and setting the thickness of the dielectric film layer, thereby further simplifying the process flow.

[0012] Optionally, the diameter of the photosensitive part of the photodetector is 0.1 mm to 5 mm, and the thickness is 120 μm to 1 mm.

[0013] Optionally, the length of any side of the photoelectric detection unit is 0.5 mm to 7 mm.

[0014] Correspondingly, the present invention also provides a method for manufacturing a spectrometer based on a photodetector array, which is used to manufacture the aforementioned spectrometer, comprising the following steps:

[0015] Coating photoresist on a carrier having a plurality of photodetectors fixed thereon, wherein the plurality of photodetectors are spaced apart on the carrier;

[0016] The photoresist is exposed and developed using a mask that matches the carrier. After development, the electrodes of the photodetector are covered by the photoresist, and the photosensitive portion of the photodetector is exposed.

[0017] Performing thin film growth on the photosensitive portion of the photodetector to form a dielectric film layer; the dielectric film layer comprises multiple layers of alternately replaced transparent media;

[0018] The photoresist is stripped off to expose the electrode, and the photodetector covered with the dielectric film layer and the exposed electrode form a photodetection unit;

[0019] The photoelectric detection unit is removed from the carrier and transferred to a packaging substrate for integration and interconnection to form a photoelectric detector array, which is used to form a spectrometer.

[0020] Optionally, the dielectric film layer includes at least ten layers of alternately replaced transparent media, and the material of the transparent media is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5.

[0021] Optionally, the carrier and the photodetector fixed on the carrier are coated with a filter film.

[0022] The beneficial effects of the spectrometer manufacturing method provided by the present invention are similar to the reasoning process of the beneficial effects of the aforementioned spectrometer, and will not be repeated here.

[0023] These features and advantages of the present invention will be further disclosed in the following detailed description and accompanying drawings. The preferred embodiments and means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present in each of the following text and accompanying drawings, they may be labeled with different symbols or numbers for convenience, but all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings:

[0025] FIG1 is a schematic top view of a photoelectric detection unit according to an embodiment of the present invention;

[0026] FIG2 is a schematic cross-sectional view of a photoelectric detection unit according to an embodiment of the present invention;

[0027] FIG3 is a schematic diagram of a photoelectric detection unit array according to an embodiment of the present invention;

[0028] FIG4 is a receiving spectrum of a photoelectric detection unit with filtering characteristics A and a photoelectric detection unit with filtering characteristics B in an embodiment of the present invention;

[0029] FIG5 is a diagram of the reconstruction error of 32 channels in the prior art;

[0030] FIG6 is a reconstruction error diagram according to an embodiment of the present invention;

[0031] FIG7 is a schematic diagram of a carrier and a photodetector according to an embodiment of the present invention;

[0032] FIG8 is a schematic diagram of a mask for coating a negative resist according to an embodiment of the present invention;

[0033] FIG9 is a schematic diagram of a mask for coating a positive resist according to an embodiment of the present invention;

[0034] FIG10 is a schematic diagram of forming a photoelectric detection unit on a carrier according to an embodiment of the present invention;

[0035] FIG11 is a schematic diagram of transferring photoelectric detection units of different heats to a substrate according to an embodiment of the present invention;

[0036] FIG12 is a schematic diagram of a photoelectric detection unit array according to an embodiment of the present invention;

[0037] FIG13 is a schematic diagram showing the positional relationship between a light source, a photodetector array, and a sample to be measured when a spectrometer collects backscattered light in an embodiment of the present invention;

[0038] FIG14 is a schematic diagram showing the positional relationship among the light source, the photodetector array, and the sample to be measured when the spectrometer collects forward scattered light in an embodiment of the present invention.

[0039] Among them, 1-photodetector, 11-photosensitive part, 12-electrode, 2-carrier, 3-mask, 4-photodetection unit, 41-photosensitive area, 42-dielectric film layer, 5-light source, 6-sample to be tested, 7-substrate. DETAILED DESCRIPTION

[0040] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0041] Reference in this specification to "one embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment of the present patent disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment. Example

[0042] This embodiment also provides a spectrometer comprising a photodetection unit array, which includes a plurality of photodetection units 4. As shown in Figures 1 and 2, the photodetection unit 4 comprises a photodetector 1 and a dielectric film layer 42. The photodetector 1 comprises a photosensitive portion 11 and an electrode 12. The photosensitive portion 11 has a diameter of 0.1 mm to 5 mm and a thickness of 120 μm to 1 mm. The electrode 12 has a diameter of 50 μm to 1 mm. The dielectric film layer 42 covers the photosensitive portion 12. The transparent medium comprises at least ten layers, and its material is Si, SiO2, SiN, SiON, Ti3O5, or Ta2O5. The material and / or thickness of each layer of the transparent medium differ from the adjacent two layers. In this embodiment, SiO2 and Ti3O5 are preferably used as the transparent medium. Therefore, the dielectric film layer 42 formed is composed of a layer of SiO2, a layer of Ti3O5, and a layer of SiO2, arranged alternately. The thickness of the dielectric film layer 42 formed is 1 μm to 100 μm. By changing the material selection of the transparent medium, the number of layers, and the thickness of the dielectric film layer, the purpose of producing photoelectric detection units with different filtering characteristics is achieved. The production of a variety of photoelectric detection units with different filtering characteristics can be completed through multiple furnaces, simplifying the process. The shape of the photoelectric detection unit 4 is preferably rectangular, and its side length is 0.5mm to 7mm. In other embodiments, the photoelectric detection unit can also be in a shape such as a triangle or a rectangle, and any side length is 0.5mm to 7mm.

[0043] It should be noted that the photodetection units that make up the photodetection unit array are multiple photodetection units with different filtering characteristics. As shown in Figure 3, the multiple photodetection units 4 on the substrate 7 have different filtering characteristics, respectively represented by numbers A, B, C, D... Figure 4 shows the received spectrum of the photodetection unit with filtering characteristic A and the received spectrum of the photodetection unit with filtering characteristic B.

[0044] The reconstruction error of 32 channels in the prior art is shown in FIG5 , and its spectral reconstruction range is 100 nm. In this embodiment, the reconstruction error is shown in FIG6 . Comparing the two, it can be seen that the relative error of this embodiment has been improved by about one-fold, and the spectral reconstruction range is 700 nm, which has also been greatly improved. Moreover, this embodiment only requires 16 channels. Therefore, this embodiment achieves better relative error performance and a larger spectral reconstruction range under the premise of requiring fewer channels. The spectrometer of the prior art needs to place a filter in front of the photodetector, and the numerical aperture of the filter is small, and the numerical aperture is closely related to the light collection ability. Therefore, the spectrometer of the prior art is limited by the small numerical aperture of the filter and has to consider the angle of light collection to collect as much light as possible. However, the numerical aperture and the stability of the spectral characteristics of the filter are contradictory to each other. Even if integrated by coupling, on the one hand, the stability of the spectral characteristics of the light collection cannot be guaranteed, and on the other hand, it will still bring about large losses. In this embodiment, the dielectric film layer 42 is directly grown on the photosensitive part 11 of the photodetector 1, which is equivalent to directly attaching the filter to the photodetector 1. All light projected on the dielectric film layer 42 can be absorbed, thereby eliminating the influence of the numerical aperture, thereby increasing the light receiving area, thereby increasing the light collecting area, reducing the loss caused by optical coupling, and thus enhancing the luminous flux of the photodetector 1. At the same time, it can also ensure the stability of the spectral characteristics of the collected light.

[0045] At the same time, this embodiment also provides a method for manufacturing a spectrometer based on a photodetector array, which is used to manufacture the aforementioned spectrometer, comprising the following steps:

[0046] Step 1: Evenly coat photoresist on a carrier 2 on which several photodetectors 1 are fixed. In this embodiment, the diameter of the photosensitive portion 11 of the photodetector 1 is 0.1 mm to 5 mm, the thickness is 120 μm to 1 mm, and the diameter of the electrode 12 of the photodetector 1 is 50 μm to 1 mm. The carrier 2 and the photodetector 1 fixed on the carrier 2 are both coated with a filter film for filtering light. Several photodetectors 1 on the carrier 2 are arranged at intervals on the carrier 2, as shown in Figure 7. In this embodiment, the carrier 2 is circular and has a limiting area, and the photodetectors 1 are arranged at intervals within the limiting area. In other embodiments, the carrier 2 can also be rectangular or other shapes, which is not limited here. The limiting area of ​​the carrier 2 can be delineated by those skilled in the art based on factors such as the shape and size of the carrier and the working area of ​​the photolithography machine, which is not limited here.

[0047] Step 2: Expose and develop the photoresist using a mask 3 that matches the carrier 2. In this embodiment, the mask 3 is circular. As shown in Figure 8, if the photoresist coated on the carrier 2 holding the photodetector 1 is a negative photoresist, the portion of the mask 3 corresponding to the electrode 12 of the photodetector 1, i.e., the dotted white circle in Figure 2, should be exposed from the mask 3. All other portions, including the photosensitive portion 11 of the photodetector 1, should be blocked by the mask 3. After exposure and development, the portion blocked by the mask 3 dissolves due to lack of exposure, leaving the photosensitive portion 11 exposed. The portion not blocked by the mask 3 remains due to exposure, leaving the electrode 12 covered by the photoresist.

[0048] As shown in Figure 9, if the photoresist coated on the carrier 2 holding the photodetector 1 is a positive photoresist, the portion of the mask 3 corresponding to the electrode 12 of the photodetector 1, i.e., the dotted gray circle in Figure 3, should be blocked by the mask 3, while the remaining portion, including the photosensitive portion 11 of the photodetector 1, should be exposed from the mask 3. After exposure and development, the portion not blocked by the mask 3 dissolves due to the exposure, exposing the photosensitive portion 11; the portion blocked by the mask 3 remains unexposed, thus covering the electrode 12 with photoresist.

[0049] Step 3: Thin film growth is performed on the photosensitive portion 11 of the photodetector 1 to form a dielectric film layer. Thin film growth is a conventional technical means in this field and will not be described in detail here. After growth, the dielectric film layer includes multiple layers of alternately replaced transparent media. The transparent media has at least ten layers, and its material is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5. The material of each layer of transparent media is different from that of the two adjacent layers. In this embodiment, the transparent media preferably uses SiO2 and Ti3O5. Therefore, the dielectric film layer formed is a layer of SiO2, a layer of Ti3O5, and then a layer of SiO2, which are arranged alternately. The thickness of the formed dielectric film layer is 1μm to 100μm. By changing the selection of the transparent medium, the number of layers, and the thickness of the dielectric film layer, the purpose of producing photoelectric detection units with different filtering characteristics is achieved. The production of photoelectric detection units with multiple different filtering characteristics can be completed through multiple furnaces, simplifying the process flow.

[0050] Step 4: Strip the photoresist to expose the electrode 12. As shown in FIG10 , the photodetector 1 covered with the dielectric film layer and the exposed electrode 12 form a photodetection unit 4, and the photosensitive portion 11 covered with the dielectric film layer serves as the photosensitive area 41 of the photodetection unit 4. In this embodiment, the shape of the photodetection unit 4 is preferably rectangular, with a side length of 0.5 mm to 7 mm. In other embodiments, the photodetection unit may also be in a triangular, rectangular, or other shape, with any side length of 0.5 mm to 7 mm.

[0051] Step 5: Remove the photodetector unit 4 from the carrier 2 and transfer it to a packaging substrate for integration and interconnection to form a photodetector array, which in turn forms a spectrometer.

[0052] The photoelectric detection units that constitute the photoelectric detection unit array are photoelectric detection units with multiple different filtering characteristics. As shown in Figure 11, the multiple photoelectric detection units 4 on the substrate 7 have different filtering characteristics, which are represented by numbers A, B, C, D... respectively. The photoelectric detection unit 4 with filtering characteristic A, the photoelectric detection unit 4 with filtering characteristic B, and the photoelectric detection unit 4 with filtering characteristic C are each completed by three furnaces. In other words, the photoelectric detection unit 4 with filtering characteristic A, the photoelectric detection unit 4 with filtering characteristic B, and the photoelectric detection unit 4 with filtering characteristic C are respectively coated with photoresist, exposed and developed, thin film grown, and stripped of photoresist by different carriers 2, and then removed from the carriers 2 and transferred to the packaging substrate 7 for integration and interconnection to form a photodetector array.

[0053] As shown in Figure 12, in this embodiment, the substrate is designed in a ring shape and includes interconnect structures or circuitry for collecting and processing detected intensity information. Therefore, the photodetector array on the substrate also has a ring shape. As shown in Figure 13, when the spectrometer collects backscattered light, the light source 5 is above the ring photodetector array, and the sample 6 is below the spectrometer. Light emitted by the light source 5 passes through the hollow portion of the ring photodetector array to reach the sample 6, where it is reflected and collected by the ring photodetector array. As shown in Figure 14, when the spectrometer collects forward scattered light, the sample 6 is below the light source 5 and the ring photodetector array. Light emitted by the light source 5 is scattered by the sample 6 and collected by the ring photodetector array. As can be seen from the curves in Figures 6 and 7, the light collected by each photodetector unit in the ring photodetector array is consistently positioned relative to the incident light. This demonstrates that, thanks to the inventive concept of the photodetector unit 1 forming an array, the photodetector unit 1 can be flexibly modified according to needs, requiring only the design of the corresponding substrate. This reduces manufacturing costs and assembly alignment requirements, increases flexibility, and eliminates the need for multiple molds. Saves mold costs

[0054] The technical solution provided in this embodiment directly grows the dielectric film layer on the photodetector 1, which can eliminate the influence of the numerical aperture, increase the aperture and thus increase the light receiving area, thereby increasing the light collecting area, reducing the loss caused by optical coupling, and thus enhancing the luminous flux of the photodetector 1.

[0055] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A spectrometer, characterized in that, The spectrometer includes a photoelectric detection unit array, the photoelectric detection unit array includes a number of photoelectric detection units, the photoelectric detection unit includes a photodetector and a dielectric film layer, the photodetector includes a photosensitive part and an electrode, the dielectric film layer covers the photosensitive part, and the electrode is exposed.

2. The spectrometer according to claim 1, wherein, The dielectric film layer includes multiple layers of transparent dielectrics, and there are material and / or thickness differences between adjacent transparent dielectrics.

3. The spectrometer according to claim 2, characterized in that, There are at least ten layers of the transparent dielectric, and they are alternately replaced.

4. The spectrometer according to claim 2, wherein The material of the transparent dielectric is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5.

5. The spectrometer according to any one of claims 1 to 4, characterized in that, The thickness of the dielectric film layer is 1 μm to 100 μm.

6. The spectrometer according to any one of claims 1 to 4, characterized in that, The diameter of the photosensitive part of the photodetector is 0.1 mm to 5 mm, and the thickness is 120 μm to 1 mm.

7. The spectrometer according to any one of claims 1 to 4, characterized in that, Any side length of the photoelectric detection unit is 0.5 mm to 7 mm.

8. A method for manufacturing a spectrometer based on a photodetector array, characterized in that, The method for manufacturing the spectrometer is used to manufacture the spectrometer according to claim 1, and includes the following steps: Coat photoresist on a carrier fixed with a number of photodetectors, and the number of the photodetectors are arranged at intervals on the carrier; Use a mask plate matching the carrier to expose and develop the photoresist. After development, the electrode of the photodetector is covered by the photoresist, and the photosensitive part of the photodetector is exposed; Perform thin film growth on the photosensitive part of the photodetector to form a dielectric film layer; the dielectric film layer includes multiple layers of alternately replaced transparent dielectrics; Strip the photoresist to expose the electrode, and the photodetector covered with the dielectric film layer and the exposed electrode form a photoelectric detection unit; Remove the photoelectric detection unit from the carrier and transfer it to a packaging substrate for integration and interconnection to form a photodetector array, and form a spectrometer from the photodetector array.

9. The method for manufacturing a spectrometer according to claim 8, characterized in that, The dielectric film layer includes at least ten layers of alternately replaced transparent dielectrics, and the material of the transparent dielectric is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5.

10. The method for manufacturing a spectrometer according to claim 8 or 9, characterized in that, The carrier and the photodetectors fixed on the carrier are coated with a filter film.

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