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

Abstract

The present invention discloses a spectrometer based on a photodetector array and a manufacturing method thereof, which relates to the technical field of reconstruction spectrometers, and includes a photodetection unit array, wherein the photodetection unit array includes a plurality of photodetection units, wherein the photodetection 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. The present invention can eliminate the influence of numerical aperture, increase the light receiving area, reduce the optical coupling loss, and achieve simple process.

Description

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] In the prior art, the reconstruction spectrometer adopts a technical route of separating the filter and the photodetector. The photodetector does not have filtering characteristics and has a relatively uniform response in a wide spectral range, while the filter is an independent device and is integrated with the photodetector through coupling. Under this technical route, in order to ensure the stability of the spectral characteristics of the filter, the numerical aperture (NA) of the filter is usually small, which brings huge losses to the front-end coupling. The related solutions combining CMOS imaging sensors with multi-filtering characteristic films are essentially to separate the filter from the photodetector, and then transfer the filter film to the CMOS imaging sensor through some special processes. However, this kind of ultra-surface filter film has extremely high requirements for the process, and the transfer process is difficult and has extremely high requirements for 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 the optical coupling loss, and simplify the process.

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

[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. Therefore, the influence of the numerical aperture is eliminated, the light receiving area is increased, 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 constituting an array, the photodetection unit can be flexibly changed according to demand, and only the corresponding substrate needs to be designed. The production cost and assembly alignment requirements are reduced, the flexibility is increased, and there is no need to open the mold multiple times. 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 medium film layer includes multiple layers of transparent medium, and there are differences in material and / or thickness between adjacent transparent mediums.

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

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

[0010] Optionally, the thickness of the dielectric film layer is 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, the setting of the number of layers, and the thickness of the medium film layer, thereby further simplifying the process flow.

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

[0013] Optionally, any side length 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 on which a plurality of photodetectors are fixed, wherein the plurality of photodetectors are spaced apart on the carrier;

[0016] The photoresist is exposed and developed using a mask plate that matches the carrier. After development, the electrode of the photodetector is covered by the photoresist, and the photosensitive part of the photodetector is exposed;

[0017] A thin film is grown on the photosensitive part of the photodetector to form a dielectric film layer; the dielectric film layer includes 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 inference process of the beneficial effects of the aforementioned spectrometer, which will not be repeated here.

[0023] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 1 is a schematic top view of a photoelectric detection unit in an embodiment of the present invention;

[0026] Figure 2 is a cross-sectional schematic diagram of a photoelectric detection unit in an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a photoelectric detection unit array according to an embodiment of the present invention;

[0028] Figure 4 The receiving spectra of the photoelectric detection unit with A filtering characteristic and the photoelectric detection unit with B filtering characteristic in the embodiment of the present invention;

[0029] Figure 5 is a reconstruction error map of 32 channels in the prior art;

[0030] Figure 6 is a reconstruction error graph of an embodiment of the present invention;

[0031] Figure 7 is a schematic diagram of a carrier and a photoelectric detector in an embodiment of the present invention;

[0032] Figure 8 is a schematic diagram of a mask for coating a negative resist in an embodiment of the present invention;

[0033] Fig. 9 is a schematic diagram of a mask plate for coating a positive resist in an embodiment of the present invention;

[0034] Fig.10 is a schematic diagram of forming a photoelectric detection unit on a carrier in an embodiment of the present invention;

[0035] Fig.11 It is a schematic diagram of transferring photoelectric detection units of different furnaces to a substrate in an embodiment of the present invention;

[0036] Fig.12 is a schematic diagram of a photoelectric detection unit array according to an embodiment of the present invention;

[0037] Fig.13 Schematic diagram of the positional relationship between the light source, the photodetector array and the sample to be tested when the spectrometer collects backscattered light in an embodiment of the present invention;

[0038] Fig.14 Schematic diagram of the positional relationship between 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-medium film layer, 5-light source, 6-sample to be tested, 7-substrate. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, 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 with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

[0041] References in this specification to "one embodiment" or "an example" or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0042] Example:

[0043] This embodiment also provides a spectrometer, including a photoelectric detection unit array, wherein the photoelectric detection unit array includes a plurality of photoelectric detection units 4. Figure 1 and Figure 2 As shown, the photodetection unit 4 includes a photodetector 1 and a dielectric film layer 42. The photodetector 1 includes a photosensitive part 11 and an electrode 12. The diameter of the photosensitive part 11 is 0.1 mm to 5 mm, the thickness is 120 μm to 1 mm, and the diameter of the electrode 12 is 50 μm to 1 mm. The dielectric film layer 42 covers the photosensitive part 12. The transparent medium has 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 are different from the adjacent two layers. In this embodiment, the transparent medium preferably uses SiO2 and Ti3O5. Therefore, the formed dielectric film layer 42 is a layer of SiO2, a layer of Ti3O5, and another layer of SiO2, which are arranged alternately. The thickness of the formed dielectric film layer 42 is 1 μm to 100 μm. By changing the material selection, number of layers, and thickness of the dielectric film layer of the transparent medium, the purpose of making photoelectric detection units with different filtering characteristics is achieved, and 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 a rectangle with a side length of 0.5mm to 7mm. In other embodiments, the photoelectric detection unit can also be in the shape of a triangle, a rectangle, etc., with any side length of 0.5mm to 7mm.

[0044] It should be noted that the photoelectric detection units constituting the photoelectric detection unit array are a plurality of photoelectric detection units with different filtering characteristics. Figure 3 As shown, the multiple photoelectric detection units 4 on the substrate 7 have different filtering characteristics, which are represented by numbers A, B, C, D, . . . respectively. Figure 4 The received spectrum of the photodetection unit with A filter characteristics and the received spectrum of the photodetection unit with B filter characteristics are shown.

[0045] The reconstruction error of 32 channels in the prior art is as follows: Figure 5 As shown in FIG. , the spectral reconstruction range is 100 nm. In this embodiment, the reconstruction error is as follows: Figure 6As shown. Comparing the two, it can be seen that the relative error of this embodiment has been improved by about one time, and the spectral reconstruction range is 700nm, 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 in 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 collecting ability. Therefore, the spectrometer in the prior art is limited by the small numerical aperture of the filter and has to consider the light collecting angle 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 they are integrated by coupling, on the one hand, the stability of the spectral characteristics of the collected light 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, while also ensuring the stability of the spectral characteristics of the collected light.

[0046] 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:

[0047] Step 1: Evenly coat photoresist on a carrier 2 on which a plurality of 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 coated with a filter film for filtering light. The plurality of photodetectors 1 on the carrier 2 are arranged at intervals on the carrier 2, such as Figure 7 As shown, in this embodiment, the carrier 2 is circular and has a limiting area, and the photodetectors 1 are arranged at intervals in the limiting area. In other embodiments, the carrier 2 may also be rectangular or other shapes, which are 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 lithography machine, which are not limited here.

[0048] Step 2: Use a mask 3 that matches the carrier 2 to expose and develop the photoresist. In this embodiment, the mask 3 is circular. Figure 8 As shown, if the photoresist coated on the carrier 2 on which the photodetector 1 is fixed is a negative photoresist, then the corresponding position of the electrode 12 of the photodetector 1 on the mask 3 is Figure 2The white circle of the middle dotted line should be exposed from the mask 3, and the other parts, including the photosensitive part 11 of the photodetector 1, should be blocked by the mask 3. After exposure and development, the part blocked by the mask 3 is dissolved due to non-exposure, so the photosensitive part 11 is exposed; the part not blocked by the mask 3 is retained due to exposure, so the electrode 12 is covered by the photoresist.

[0049] like Fig. 9 As shown, if the photoresist coated on the carrier 2 on which the photodetector 1 is fixed is a positive photoresist, then the corresponding position of the electrode 12 of the photodetector 1 on the mask 3 is Figure 3 The gray circle of the middle dotted line should be blocked by the mask 3, and the other parts, including the photosensitive part 11 of the photodetector 1, should be exposed from the mask 3. After exposure and development, the part not blocked by the mask 3 is dissolved due to exposure, so the photosensitive part 11 is exposed; the part blocked by the mask 3 is retained because it is not exposed, so the electrode 12 is covered by the photoresist.

[0050] Step 3: Perform thin film growth on the photosensitive part 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 here. After growth, the dielectric film layer includes multiple layers of transparent media that are replaced alternately. The transparent medium has at least ten layers, and its material is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5. The material of each layer of transparent medium is different from the two adjacent layers. In this embodiment, the transparent medium 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 dielectric film layer formed is 1μm to 100μm. By changing the selection of the transparent medium, the setting of the number of layers, and the thickness setting of the dielectric film layer, the purpose of manufacturing 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, which simplifies the process flow.

[0051] Step 4: Strip the photoresist to expose the electrode 12. Fig.10 As shown, 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 a photosensitive area 41 of the photodetection unit 4. In this embodiment, the shape of the photodetection unit 4 is preferably a rectangle 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.

[0052] Step 5: Remove the photoelectric detection unit 4 from the carrier 2 and transfer it to the packaging substrate for integration and interconnection to form a photoelectric detector array, and the photoelectric detector array forms a spectrometer.

[0053] The photoelectric detection units constituting the photoelectric detection unit array are a plurality of photoelectric detection units with different filtering characteristics. Fig.11 As shown, the multiple photodetection units 4 on the substrate 7 have different filtering characteristics, which are represented by numbers A, B, C, D... respectively. The photodetection unit 4 with filtering characteristic A, the photodetection unit 4 with filtering characteristic B, and the photodetection unit 4 with filtering characteristic C are respectively completed by three furnaces. In other words, the photodetection unit 4 with filtering characteristic A, the photodetection unit 4 with filtering characteristic B, and the photodetection unit 4 with filtering characteristic C are respectively removed from different carriers 2 after being coated with photoresist, exposed and developed, thin film grown, and stripped of photoresist, and then transferred to the packaging substrate 7 for integration and interconnection to form a photodetector array.

[0054] like Fig.12 As shown, in this embodiment, the substrate is designed to be ring-shaped and includes an interconnection structure or a circuit structure for collecting and processing the detected intensity information. Therefore, the photodetector array on the substrate is also ring-shaped. Fig.13 As shown, when the spectrometer collects backscattered light, the light source 5 is above the ring photodetector array, and the sample 6 to be tested is below the spectrometer. The light emitted by the light source 5 passes through the hollow part of the ring photodetector array to reach the sample 6 to be tested, and is reflected by the sample 6 to be tested and collected by the ring photodetector array. Fig.14 As shown, when the spectrometer collects forward scattered light, the sample 6 to be tested is below the light source 5, and the ring photodetector array is below the sample 6 to be tested. The light emitted by the light source 5 is scattered by the sample 6 to be tested and collected by the ring photodetector array. Figure 6 and Figure 7 It can be seen from the curve in that the light collected by each photodetection unit of the annular photodetector array is consistent in relative position with respect to the incident light. It can be seen that, thanks to the inventive concept of the photodetection unit 1 forming an array, the photodetection unit 1 can be flexibly changed according to demand, and only the corresponding substrate needs to be designed. The production cost and assembly alignment requirements are reduced, the flexibility is increased, and there is no need to open the mold multiple times. The mold cost is saved

[0055] 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 thereby enhancing the luminous flux of the photodetector 1.

[0056] The above are only specific embodiments of the present invention, but the protection scope 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 modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A method for manufacturing a spectrometer based on a photodetector array, characterized in that: The spectrometer manufacturing method is used to manufacture a spectrometer, and comprises the following steps: Coating photoresist on a carrier on which a plurality of photodetectors are fixed, wherein the plurality of photodetectors are spaced apart on the carrier; The photoresist is exposed and developed using a mask plate that matches the carrier. After development, the electrode of the photodetector is covered by the photoresist, and the photosensitive part of the photodetector is exposed; A thin film is grown on the photosensitive part of the photodetector to form a dielectric film layer; the dielectric film layer includes multiple layers of alternately replaced transparent media; 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; 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.

2. The method for manufacturing a spectrometer according to claim 1, characterized in that: 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.

3. The method for manufacturing a spectrometer according to claim 1 or 2, characterized in that: The carrier and the photoelectric detector fixed on the carrier are coated with a filter film.

4. A spectrometer, characterized in that: The spectrometer is manufactured using the spectrometer manufacturing method as claimed in claim 1, wherein the spectrometer includes a photoelectric detection unit array, the photoelectric detection unit array includes a plurality 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.

5. The spectrometer according to claim 4, characterized in that The medium film layer includes multiple layers of transparent medium, and there are differences in material and / or thickness between adjacent transparent mediums.

6. The spectrometer according to claim 5, characterized in that The transparent medium is provided with at least ten layers and is replaced alternately.

7. The spectrometer according to claim 5, characterized in that The material of the transparent medium is Si, SiO2, SiN, SiON, Ti3O5 or Ta2O5.

8. The spectrometer according to any one of claims 4 to 7, characterized in that The thickness of the dielectric film layer is 1 μm to 100 μm.

9. The spectrometer according to any one of claims 4 to 7, characterized in that: The photosensitive portion of the photodetector has a diameter of 0.1 mm to 5 mm and a thickness of 120 μm to 1 mm.

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

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