Image sensor and preparation method thereof

Abstract

The invention relates to an image sensor and a preparation method thereof. The image sensor comprises a substrate, photosensitive elements arranged in an array, a filter layer, a micro-lens layer and at least two stacked anti-reflection layers, the photosensitive elements are located above the substrate, the filter layer is located above the photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used for transmitting light in a first wave band range, and the second filter unit is used for transmitting light in a second wave band range. The first light filtering unit is used for transmitting light in a first wave band range, the second light filtering unit is used for transmitting light in a second wave band range, the micro-lens layer is located above the light filtering layer and comprises a first micro-lens and a second micro-lens, the first micro-lens is located above the first light filtering unit, and the second micro-lens is located above the second light filtering unit; the at least two stacked anti-reflection layers are located above the first microlenses. According to the invention, the anti-reflection layer can be prepared above one or a part of filtering units in the filtering layer in a targeted manner, and the optical efficiency of one or a part of filtering units is independently and further improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an image sensor and a method for preparing the same. Background Art

[0002] In the related art, image sensors, such as complementary metal oxide semiconductor image sensors (CMOS image sensors, CIS) and charge coupled device (CCD) image sensors, generally use a series of photodiodes formed in an array of pixel regions of a semiconductor substrate to sense when light impacts the photodiodes. Complementary metal oxide semiconductor image sensors can generally be formed in either a front side illumination group or a back side illumination group. In the front side illumination group, light is incident from the "front" side of the image sensor and is transmitted to the photodiode through the transfer transistor formed thereon. In the back side illumination group, the transfer transistor, metal layer and dielectric layer are formed on the back side of the substrate, the photodiode is formed on the front side, and the light is allowed to pass from the "back" side of the substrate to the photodiode so that the light hits the photodiode before it reaches the transfer transistor, dielectric layer, or metal layer. CIS may include color filters, microlenses, and anti-reflection coatings (ARCs) that allow light of different wavelengths and more light to reach the photodiode.

[0003] The conventional method of adding an anti-reflective coating on the microlens is to deposit an anti-reflective film on the microlens through a chemical vapor deposition device. However, only one anti-reflective film can be prepared through the chemical vapor deposition method, and this film can only slightly increase the transmittance of light in each pixel and reduce the reflection of light to improve the optical efficiency of the overall pixel.

[0004] In addition, in some application scenarios, for example, the optical quantum efficiency of the green filter film and the blue filter film in the color filter is higher, and the quantum efficiency of the red filter film is lower. Depositing an anti-reflection layer on the microlens cannot solve image problems such as inaccurate image color, color imbalance, reduced red image signal-to-noise ratio, and imbalanced brightness and contrast. Summary of the invention

[0005] The purpose of the present application is to provide an image sensor and a method for preparing the same, which can specifically prepare an anti-reflection layer above a certain filter unit or a certain part of the filter layer, and can further improve the optical efficiency of a certain filter unit or a certain part of the filter unit separately, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0006] According to a first aspect of an embodiment of the present application, there is provided an image sensor, including: substrate; Photosensitive elements arranged in an array are located above the substrate; A filter layer is located above the photosensitive element; the filter layer includes a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; a microlens layer, located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit; At least two stacked anti-reflection layers are located above the first microlens and are used to reduce the reflectivity of light within the first wavelength band.

[0007] In one embodiment, in a direction from the substrate to the photosensitive element, the refractive index of the anti-reflection layer decreases sequentially.

[0008] In one embodiment, the image sensor comprises a first anti-reflection layer and a second anti-reflection layer stacked together, wherein the first anti-reflection layer is located above the first microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The refractive index of the first anti-reflection layer to visible light is 1.4-1.5, the refractive index of the second anti-reflection layer to visible light is 1.25-1.26, and the wavelength range of visible light is 400-700 nm.

[0009] In one embodiment, the refractive index of the first anti-reflection layer is 1.46, and the refractive index of the second anti-reflection layer is 1.25.

[0010] In one embodiment, the image sensor further includes a first adhesion layer and a second adhesion layer; The first adhesion layer is located above the first microlens, the first anti-reflection layer is located above the first adhesion layer, the second adhesion layer is located above the first anti-reflection layer, and the second anti-reflection layer is located above the second adhesion layer.

[0011] In one embodiment, the image sensor further comprises a first adhesion layer; The first anti-reflection layer is also located above the second microlens, and the first adhesion layer is located above the first anti-reflection layer; The first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens; The first adhesive layer includes a first adhesive film and a second adhesive film, the first adhesive film is located above the first sub-anti-reflection film, and the second adhesive film is located above the second sub-anti-reflection film; The second anti-reflection layer is located on the first adhesive film.

[0012] According to a second aspect of an embodiment of the present application, a method for preparing an image sensor is provided, comprising: A semiconductor device is provided, the semiconductor device comprising a substrate, array-arranged photosensitive elements, a filter layer and a microlens layer, the photosensitive elements are located above the substrate, the filter layer is located above the photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; the microlens layer is located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit; At least two stacked anti-reflection layers are formed above the first microlens, and the anti-reflection layers are used to reduce the reflectivity of light within the first wavelength band.

[0013] In one embodiment, the image sensor includes a first anti-reflection layer and a second anti-reflection layer stacked together, the first anti-reflection layer is located above the first microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The at least two stacked anti-reflection layers are formed above the first microlens, comprising: forming a sacrificial material layer, wherein the sacrificial material layer is located above the microlens layer; forming a sacrificial layer opening on the sacrificial material layer to obtain a sacrificial layer; the sacrificial layer opening is used to expose the first microlens; forming a first anti-reflection material layer, wherein the first anti-reflection material layer comprises a first anti-reflection layer and a first anti-reflection film layer to be removed, wherein the first anti-reflection film layer to be removed is located above the sacrificial layer, and the first anti-reflection layer is located above the first microlens; forming a second anti-reflection material layer, wherein the second anti-reflection material layer comprises a second anti-reflection layer and a second anti-reflection film layer to be removed, wherein the second anti-reflection film layer to be removed is located above the first anti-reflection film layer to be removed, and the second anti-reflection layer is located above the first anti-reflection layer; The sacrificial layer, the first anti-reflection film layer to be removed, and the second anti-reflection film layer to be removed are peeled off to obtain the image sensor.

[0014] In one embodiment, before forming the sacrificial material layer, the method further comprises: forming a first adhesive layer above the microlens layer; the first adhesive layer comprises a first adhesive film, and the first adhesive film is located above the first microlens; The forming of the sacrificial material layer comprises: forming the sacrificial material layer above the first adhesion layer; After forming a sacrificial layer opening on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesive film; After forming the first anti-reflection material layer, the first anti-reflection layer is located above the first adhesive film, and the first anti-reflection film layer to be removed is located above the sacrificial layer; Before forming the second anti-reflection material layer, the method further comprises: forming a second adhesion layer and a fourth adhesion layer on the first anti-reflection material layer, wherein the second adhesion layer is located on the first anti-reflection layer, and the fourth adhesion layer is located on the first anti-reflection film layer to be removed; After forming the second anti-reflection material layer, the second anti-reflection layer is located above the second adhesion layer, and the second anti-reflection film layer to be removed is located above the fourth adhesion layer; When the sacrificial layer, the first anti-reflection film layer to be removed, and the second anti-reflection film layer to be removed are peeled off, the fourth adhesive layer is also peeled off.

[0015] In one embodiment, the image sensor includes a first anti-reflection layer and a second anti-reflection layer stacked together, the first anti-reflection layer is located above the first microlens and the second microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The at least two stacked anti-reflection layers are formed above the first microlens, comprising: The first anti-reflection layer is formed above the microlens layer; the first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens; forming a sacrificial material layer; the sacrificial material layer is located above the first anti-reflection layer; forming a sacrificial layer opening on the sacrificial material layer to obtain a sacrificial layer; the sacrificial layer opening is used to expose the first sub-anti-reflection film; forming a second anti-reflection material layer, wherein the second anti-reflection material layer comprises a second anti-reflection layer and a second anti-reflection film layer to be removed, wherein the second anti-reflection film layer to be removed is located above the sacrificial layer, and the second anti-reflection layer is located above the first sub-anti-reflection film; The sacrificial layer and the second anti-reflection film layer to be removed are peeled off to obtain the image sensor.

[0016] In one embodiment, before forming the sacrificial material layer, the method further comprises: forming a first adhesive layer on the first anti-reflection layer; the first adhesive layer comprises a first adhesive film, and the first adhesive film is located on the first sub-anti-reflection film; The forming of the sacrificial material layer comprises: forming the sacrificial material layer above the first adhesion layer; After forming a sacrificial layer opening on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesive film; After the second anti-reflection material layer is formed, the second anti-reflection layer is located above the first adhesive film, and the second anti-reflection film layer to be removed is located above the sacrificial layer.

[0017] Compared with the prior art, the beneficial effects of the present application are as follows: the image sensor comprises a substrate, array-arranged photosensitive elements, a filter layer, a microlens layer and at least two stacked anti-reflection layers, the array-arranged photosensitive elements are located above the substrate, the filter layer is located above the array-arranged photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used to transmit light in a first wavelength range, the second filter unit is used to transmit light in a second wavelength range, the microlens layer is located above the filter layer, the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, the second microlens is located above the second filter unit, and at least two stacked anti-reflection layers are located above the first microlens to further reduce the reflection of the light in the first wavelength range. The reflectivity of the light in the first wavelength range can be further reduced by at least two stacked anti-reflection layers, that is, there are at least two stacked anti-reflection layers above the first filter unit. Since the at least two stacked anti-reflection layers can further reduce the reflectivity of the light in the first wavelength range, the light transmittance of the light in the first wavelength range can be improved. Therefore, the optical efficiency of the first filter unit can be further improved, and then the optical efficiency of the photosensitive element for sensing the light in the first wavelength range can be further improved. That is, at least two stacked anti-reflection layers can be specifically prepared above one or part of the filter units in the filter layer, and the optical efficiency of one or part of the filter units can be further improved separately, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0018] When the image sensor includes a stacked first anti-reflection layer and a second anti-reflection layer, the first anti-reflection layer is located above the first microlens, the second anti-reflection layer is located above the first anti-reflection layer, and the refractive index of the first anti-reflection layer is 1.46 and the refractive index of the second anti-reflection layer is 1.25, the optical efficiency of the first filtering unit can be improved by about 3%-4%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a schematic diagram showing the structure of an image sensor according to an exemplary embodiment.

[0020] Figure 2 is a schematic structural diagram of an image sensor according to another exemplary embodiment.

[0021] Figure 3 is a schematic structural diagram of an image sensor according to another exemplary embodiment.

[0022] Figure 4 The figure is a flow chart of a method for manufacturing an image sensor according to an exemplary embodiment.

[0023] Figure 5-Figure 11 Schematic diagram of the intermediate structure produced during the preparation process of the image sensor.

[0024] Fig.12 The figure is a flow chart of a method for manufacturing an image sensor according to an exemplary embodiment.

[0025] Figure 13-Figure 15 Schematic diagram of the intermediate structure produced during the preparation process of the image sensor. DETAILED DESCRIPTION

[0026] Unless otherwise defined, the technical terms or scientific terms used in this specification and claims shall have the usual meanings understood by persons with ordinary skills in the technical field to which the invention belongs. The specific embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be noted that in the specific description of these embodiments, in order to provide a concise description, it is impossible for this specification to provide a detailed description of all the features of the actual embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art may modify and replace the embodiments of the present invention, and the resulting embodiments are also within the scope of protection of the present invention.

[0027] In the related technology, in a complementary metal oxide semiconductor image sensor, when the filter layer adopts the bayer pattern (Bayer array, a color filter matrix), the optical quantum efficiency of the green filter unit and the blue filter unit is higher, and the quantum efficiency of the red filter unit is lower, which will cause image problems such as inaccurate color, color imbalance, reduced signal-to-noise ratio of the red image, and imbalance in brightness and contrast of the image captured by the image sensor.

[0028] In order to solve the above technical problems, the present application proposes an image sensor and a preparation method thereof, which can specifically prepare an anti-reflection layer above one or a part of the filter units in the filter layer, and can individually improve the optical efficiency of one or a part of the filter units, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0029] It should be noted that the “pixel” referred to herein refers to a photosensitive element, such as a photodiode.

[0030] An embodiment of the present application provides an image sensor. The image sensor is used to collect images and can be applied to electronic devices with image collection functions, such as cameras, mobile phones, tablet computers, notebook computers, computers, and monitoring equipment.

[0031] like Figure 1 As shown, the image sensor includes a pixel area 100. The pixel area 100 may include array-arranged photosensitive elements (not shown) and related circuits (not shown). The array-arranged photosensitive elements may include a first photosensitive element and a second photosensitive element, and the first photosensitive element and the second photosensitive element may sense a visible light band.

[0032] In one embodiment, a red filter unit may be disposed above the first photosensitive element to allow only red light to pass through, and thus the first photosensitive element is used to sense red light and is a red light photosensitive element. The second photosensitive element may include a first sub-photosensitive element and a second sub-photosensitive element, and a green filter unit is disposed above the first sub-photosensitive element to allow only green light to pass through, and thus the first sub-photosensitive element is used to sense green light and is a green light photosensitive element. A blue filter unit is disposed above the second sub-photosensitive element to allow only blue light to pass through, and thus the second sub-photosensitive element is used to sense blue light and is a blue light photosensitive element.

[0033] like Figure 2As shown, the image sensor may include a substrate 1021, a first photosensitive element 1022, a second photosensitive element 1023, a filter layer CF, a microlens layer ML, a first adhesive layer 109, a first anti-reflection layer 108, a second adhesive layer 111, and a second anti-reflection layer 112. The structure including the substrate 1021, the first photosensitive element 1022, and the second photosensitive element 1023 may be referred to as an image sensor 102 with a filter layer CF to be processed.

[0034] like Figure 2 As shown, the first photosensitive element 1022 and the second photosensitive element 1023 are located on the substrate 1021 .

[0035] In one embodiment, the first photosensitive element 1022 may be a red light photosensitive element R for sensing red light, and the second photosensitive element 1023 may include the green light photosensitive element and the blue light photosensitive element mentioned above.

[0036] like Figure 2 As shown, the filter layer CF is located above the first photosensitive element 1022 and the second photosensitive element 1023 , that is, located on a side of the first photosensitive element 1022 and the second photosensitive element 1023 away from the substrate 1021 .

[0037] In one embodiment, the filter layer CF may include a first filter unit and a second filter unit, the first filter unit is adjacent to the second filter unit, the first filter unit is used to transmit light in a first wavelength band range, and the second filter unit is used to transmit light in a second wavelength band range, and there is no overlapping interval between the first wavelength band range and the second wavelength band range.

[0038] In one embodiment, the first filter unit is a red filter unit for transmitting red light, and the second filter unit includes a green filter unit and a blue filter unit. The green filter unit is for transmitting green light, and the blue filter unit is for transmitting blue light.

[0039] like Figure 1 As shown, in one embodiment, the filter layer CF may include a red filter unit 106, green filter units 104, 105, and a blue filter unit 103 arranged in an array. The red filter unit 106 is used to allow only red light within a specified wavelength range to pass through, the green filter units 104, 105 are used to allow only green light within a specified wavelength range to pass through, and the blue filter unit 103 is used to allow only blue light within a specified wavelength range to pass through. The red filter unit 106 is located above the red light sensing element R, the green filter units 104, 105 are located above the green light sensing element, and the blue filter unit 103 is located above the blue light sensing element.

[0040] Of course, in other embodiments, the filter layer CF may also include other filter units, such as a cyan filter unit, a yellow filter unit, a magenta filter unit, a near infrared filter unit, a white filter unit, and a transparent filter unit, etc. The cyan filter unit is used to transmit cyan light, the yellow filter unit is used to transmit yellow light, the magenta filter unit is used to transmit magenta light, the near infrared filter unit is used to transmit near infrared light, the white filter unit is used to reflect visible light, and the transparent filter unit is used to transmit visible light.

[0041] In one embodiment, Figure 1 As shown, the filter layer CF adopts a Bayer pattern 101. In one embodiment, as Figure 1 As shown, in the Bayer array 101, a BGGR arrangement is adopted, that is, the first row and the first column are blue filter units 103, the first row and the second column are first green filter units 104, the second row and the first column are second green filter units 105, and the second row and the second column are red filter units 106. The row direction is the X direction, the column direction is the Z direction, and the X direction is perpendicular to the Z direction. Accordingly, the green light sensing element may include a first green light sensing element and a second green light sensing element, the first green light filtering unit 104 is located above the first green light sensing element, and the second green light filtering unit 105 is located above the second green light sensing element. The blue light filtering unit 103 is located above the blue light sensing element, and the red light filtering unit 106 is located above the red light sensing element R.

[0042] In this document, the Bayer array 101 adopts the BGGR arrangement as an example for description. In other embodiments, the Bayer array 101 may also adopt other arrangements, such as GRBG arrangement, GBRG arrangement, RGGB arrangement, RYYB arrangement, RGBW arrangement or RGBNIR arrangement. Among them, the GRBG arrangement is that the first row and the first column are the first green filter unit 104, the first row and the second column are the red filter unit 106, the second row and the first column are the blue filter unit 103, and the second row and the second column are the second green filter unit 105. The GBRG arrangement is that the first row and the first column are the first green filter unit 104, the first row and the second column are the blue filter unit 103, the second row and the first column are the red filter unit 106, and the second row and the second column are the second green filter unit 105. The RGGB arrangement is a red filter unit 106 in the first row and the first column, a first green filter unit 104 in the first row and the second column, a second green filter unit 105 in the second row and the first column, and a blue filter unit 103 in the second row and the second column. The RYYB arrangement is a red filter unit 106 in the first row and the first column, a first yellow filter unit in the first row and the second column, a second yellow filter unit in the second row and the first column, and a blue filter unit 103 in the second row and the second column. The RGBW arrangement is a red filter unit in the first row and the first column, a green filter unit in the first row and the second column, a blue filter unit in the second row and the first column, and a white filter unit in the second row and the second column. The RGBNIR arrangement is a red filter unit in the first row and the first column, a green filter unit in the first row and the second column, a blue filter unit in the second row and the first column, and a near-infrared filter unit in the second row and the second column.

[0043] like Figure 2 As shown, the microlens layer ML is located above the filter layer CF. The microlens layer ML includes a microlens array formed by a plurality of microlenses 107. The microlenses 107 correspond to the photosensitive elements one by one. One microlens 107 is located above one photosensitive element. The microlens 107 is a convex lens used for focusing light to improve the light efficiency of the photosensitive element.

[0044] like Figure 2 As shown, the microlens layer ML includes a first microlens ML1 and a second microlens ML2, wherein the first microlens ML1 is located above the first filter unit, and the second microlens ML2 is located above the second filter unit. For example, the first microlens ML1 is located above the red filter unit 106, and the second microlens ML2 is located above the second green filter unit 105.

[0045] like Figure 2As shown, the first adhesion layer 109 is located above the microlens layer ML. The first adhesion layer 109 is used to increase adhesion, and the first adhesion layer 109 includes a resin material that cannot be photolithographic. The thickness of the first adhesion layer 109 is less than or equal to 10 nanometers, for example, the thickness of the first adhesion layer 109 is 6 nanometers, 8 nanometers, or 10 nanometers.

[0046] like Figure 2 As shown, the first adhesive layer 109 may include a first adhesive film 1091 and a second adhesive film 1092 . The first adhesive film 1091 is located above the first microlens ML1 , and the second adhesive film 1092 is located above the second microlens ML2 .

[0047] like Figure 2 As shown, the first anti-reflection layer 108 is located above the first adhesive layer 109. The first adhesive film 1091 is used to adhere the first anti-reflection layer 108. For example, the first anti-reflection layer 108 is located above the first adhesive film 1091 to reduce the reflectivity of red light.

[0048] like Figure 2 As shown, the second adhesion layer 111 is located above the first anti-reflection layer 108 , and the second anti-reflection layer 112 is located above the second adhesion layer 111 .

[0049] The first anti-reflection layer 108 and the second anti-reflection layer 112 are located above the red filter unit 106 . Since the first anti-reflection layer 108 and the second anti-reflection layer 112 can improve light transmittance, the optical efficiency of the red filter unit 106 can be improved.

[0050] In one embodiment, the material of the first anti-reflection layer 108 includes silicon dioxide. The material of the second anti-reflection layer 112 includes a siloxane polymer.

[0051] In one embodiment, when the first photosensitive element 1022 is a red light photosensitive element R, the refractive index of the first anti-reflection layer 108 for red light with a wavelength of 540 nm is 1.46, and the extinction coefficient is 0.

[0052] In one embodiment, the refractive index of the first anti-reflection layer to visible light is 1.4-1.5, the refractive index of the second anti-reflection layer to visible light is 1.25-1.26, and the wavelength range of visible light is 400-700 nm. For example, the refractive index of the first anti-reflection layer to visible light may be 1.4, 1.46 or 1.5, and the refractive index of the second anti-reflection layer to visible light may be 1.25, 1.255 or 1.26.

[0053] In one embodiment, the refractive index of the first anti-reflection layer is 1.46, the refractive index of the second anti-reflection layer is 1.25, and the optical efficiency of the first filter unit can be improved by about 3%-4%. When there is only the first anti-reflection layer above the first filter unit, the optical efficiency of the first filter unit can be improved by about 2%. It can be seen that when there are two anti-reflection layers above the first filter unit, and in the direction from the substrate to the photosensitive element, the refractive indices of the two anti-reflection layers decrease successively, which can further improve the optical efficiency of the first filter unit.

[0054] In other embodiments, the image sensor may include three, four or more stacked anti-reflection layers located above the first microlens, and the refractive index of each anti-reflection layer decreases sequentially in the direction from the substrate to the photosensitive element.

[0055] In one embodiment, the first anti-reflection layer 108 and the second anti-reflection layer 112 may be located only above the green filter unit 104 to improve the optical efficiency of the green filter unit 104 .

[0056] In one embodiment, the first anti-reflection layer 108 and the second anti-reflection layer 112 may be located only above the green filter unit 105 to improve the optical efficiency of the green filter unit 105 .

[0057] In one embodiment, the first anti-reflection layer 108 and the second anti-reflection layer 112 may be located only above the blue light filter unit 103 to improve the optical efficiency of the blue light filter unit 103 .

[0058] In the embodiment of the present application, there are at least two stacked anti-reflection layers above the first filter unit. Since the at least two stacked anti-reflection layers can further reduce the reflectivity of light in the first wavelength range, the optical efficiency of the first filter unit can be further improved, and then the optical efficiency of the photosensitive element for sensing light in the first wavelength range can be further improved. That is, at least two stacked anti-reflection layers can be prepared in a targeted manner above one or a part of the filter units in the filter layer, and the optical efficiency of one or a part of the filter units can be further improved separately, thereby improving the color accuracy of the captured image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0059] Another embodiment of the present application provides an image sensor. Figure 3 In this embodiment, the image sensor includes a substrate 1021 , a first photosensitive element 1022 , a second photosensitive element 1023 , a filter layer CF, a microlens layer ML, a first anti-reflection layer 108 , a first adhesion layer 109 and a second anti-reflection layer 112 .

[0060] The substrate 1021, the first photosensitive element 1022, the second photosensitive element 1023, the filter layer CF, the microlens layer ML and Figure 2 The embodiment shown is the same. Different from the above embodiment, in this embodiment, the first anti-reflection layer 108 is not only located above the first microlens ML1, but also located above the second microlens ML2, that is, the first anti-reflection layer 108 covers the first filter unit and the second filter unit, that is, the first anti-reflection layer can cover the filter layer. In this way, the optical efficiency of the entire filter layer can be improved.

[0061] like Figure 3 As shown, the first adhesive layer 109 is located above the first anti-reflection layer 108. The first anti-reflection layer 108 includes a first sub-anti-reflection film 1081 and a second sub-anti-reflection film 1082, wherein the first sub-anti-reflection film 1081 is located above the first microlens ML1, and the second sub-anti-reflection film 1082 is located above the second microlens ML2.

[0062] The first adhesive layer 109 includes a first adhesive film 1091 and a second adhesive film 1092 . The first adhesive film 1091 is located above the first sub-anti-reflection film 1081 , and the second adhesive film 1092 is located above the second sub-anti-reflection film 1082 .

[0063] The second anti-reflection layer 112 is located above the first adhesive film 1091. That is, the second anti-reflection layer 112 only covers the first filter unit. The second anti-reflection layer 112 is only used to improve the optical efficiency of the first filter unit.

[0064] In this embodiment, the first anti-reflection layer 108 covers the entire filter layer CF, and the second anti-reflection layer 112 only covers the first filter unit. In this way, not only the optical efficiency of the entire filter layer can be improved, but also the optical efficiency of the first filter unit can be further improved, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0065] In this embodiment, the refractive index of the first anti-reflection layer is 1.46, and the refractive index of the second anti-reflection layer is 1.25. The optical efficiency of the first filter unit can be increased by about 2%, and the optical efficiency of the first filter unit can be increased by about 3%-4%.

[0066] In one embodiment, the second anti-reflection layer 112 may be located only above the green filter unit 104 to improve the optical efficiency of the green filter unit 104 .

[0067] In one embodiment, the second anti-reflection layer 112 may be located only above the green filter unit 105 to improve the optical efficiency of the green filter unit 105 .

[0068] In one embodiment, the second anti-reflection layer 112 may be located only above the blue light filter unit 103 to improve the optical efficiency of the blue light filter unit 103 .

[0069] Another exemplary embodiment of the present application also provides a method for preparing an image sensor. The method for preparing an image sensor in this embodiment is used to prepare Figure 2 The image sensor shown. Figure 4 As shown, in this embodiment, the method for preparing the image sensor may include the following steps S401 to S408: Step S401, providing a semiconductor device, the semiconductor device comprising a substrate, array-arranged photosensitive elements, a filter layer and a microlens layer, the photosensitive elements are located above the substrate, the filter layer is located above the photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; the microlens layer is located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit.

[0070] In one embodiment, the first filter unit is adjacent to the second filter unit, and there is no overlapping interval between the first wavelength band range and the second wavelength band range.

[0071] In this step, if Figures 5 and 6 As shown, a semiconductor device is provided, which includes a substrate 1021, a first photosensitive element 1022, a second photosensitive element 1023, a filter layer CF and a microlens layer ML, wherein the first photosensitive element 1022 is a red light photosensitive element R, the second photosensitive element 1023 includes a green light photosensitive element G and a blue light photosensitive element B, and the green light photosensitive element G includes a first green light photosensitive element G1 and a second green light photosensitive element G2.

[0072] like Figures 5 and 6 As shown, the filter layer CF is located above the first photosensitive element 1022 and the second photosensitive element 1023. The filter layer CF includes a red filter unit 106, green filter units 104, 105 and a blue filter unit 103 arranged in an array. The green filter units 104, 105 include a first green filter unit 104 and a second green filter unit 105. The blue filter unit 103 is located above the blue light photosensitive element, and the red filter unit 106 is located above the red light photosensitive element R. The first green filter unit 104 is located above the first green light photosensitive element, and the second green filter unit 105 is located above the second green light photosensitive element.

[0073] like Figures 5 and 6 As shown, the microlens layer ML is located above the filter layer CF. The microlens layer ML includes a microlens array formed by a plurality of microlenses 107. The microlenses 107 correspond to the photosensitive elements one by one. One microlens 107 is located above one photosensitive element. The microlens 107 is a convex lens used for focusing light to improve the light efficiency of the photosensitive element.

[0074] In one embodiment, step S401 may include the following steps: first, provide an image sensor 102 with a filter layer CF to be processed, that is, an image sensor with a filter layer CF and a microlens layer ML to be processed. Then, form the filter layer CF and the microlens layer ML through coating, photolithography, development, baking, and etching processes.

[0075] Step S402 , forming a first adhesive layer above the microlens layer; the first adhesive layer includes a first adhesive film, and the first adhesive film is located above the first microlens.

[0076] In this embodiment, the material of the first adhesion layer 109 may include resin.

[0077] In this step, if Figure 7 As shown, a first adhesion layer 109 may be formed on the microlens layer ML by a spin coating process, and the first adhesion layer 109 covers the entire pixel region 100. The first adhesion layer 109 is used to increase adhesion and cannot be photolithographically processed.

[0078] like Figure 7 As shown, the first adhesive layer 109 includes a first adhesive film 1091 and a second adhesive film 1092 . The first adhesive film 1091 is located above the first microlens ML1 , and the second adhesive film 1092 is located above the second microlens ML2 .

[0079] In this embodiment, the thickness of the first adhesion layer 109 is less than or equal to 10 nanometers. For example, the thickness of the first adhesion layer 109 is 6 nanometers, 8 nanometers, or 10 nanometers.

[0080] In one embodiment, the first adhesion layer may not be formed on the microlens layer.

[0081] Step S403 , forming a sacrificial material layer on the first adhesion layer.

[0082] In this embodiment, the material of the sacrificial material layer includes photoresist. In one embodiment, the material of the sacrificial material layer may include positive photoresist. The positive photoresist may include a mixture of methyl amyl ketone (miscible in most organic solvents), propylene glycol methyl ether acetate and phenolic numerical derivatives, but is not limited thereto. In another embodiment, the material of the sacrificial material layer may include negative photoresist.

[0083] In this embodiment, the distance is described by taking the example that the material of the sacrificial material layer includes positive photoresist.

[0084] In this embodiment, a sacrificial material layer may be formed on the first adhesion layer 109 by using a spin coating process, and the sacrificial material layer covers the entire pixel region 100 .

[0085] In this embodiment, the thickness of the sacrificial material layer is 4-8 micrometers. For example, the thickness of the sacrificial material layer can be 4 micrometers, 5 micrometers, 7 micrometers or 8 micrometers.

[0086] In another embodiment, if the first adhesion layer 109 is not formed over the microlens layer, a sacrificial material layer may be formed over the microlens layer.

[0087] Step S404, forming a sacrificial layer opening on the sacrificial material layer to obtain a sacrificial layer; the sacrificial layer opening is used to expose the first adhesive film.

[0088] In this embodiment, if Figure 8 As shown, a sacrificial layer opening 120 can be formed on the sacrificial material layer by a photolithography process to obtain a sacrificial layer 110. For example, a mask is placed on the side of the sacrificial material layer away from the substrate 1021, and the mask includes a shielding portion and a mask opening, wherein the shielding portion is located above the second microlens ML2, and the mask opening is located above the first microlens ML1, and the mask opening is used to expose the sacrificial material layer above the first microlens ML1. An exposure process is used to expose the sacrificial material layer exposed by the mask opening, that is, ultraviolet light is irradiated to the mask, and the sacrificial material layer exposed by the mask opening is irradiated by ultraviolet light, and the sacrificial material layer irradiated by ultraviolet light undergoes molecular cleavage. Then, a development process is used to remove the sacrificial material layer irradiated by ultraviolet light, that is, the sacrificial material layer that has undergone molecular cleavage is removed by dissolving the sacrificial material layer that has undergone molecular cleavage with a developer, and the unexposed sacrificial material layer is retained, thereby obtaining a sacrificial layer 110 having a sacrificial layer opening 120. The unexposed sacrificial material layer covers the second adhesive film 1092. The sacrificial layer opening 120 is used to expose the first adhesive film 1091 of the adhesive layer 109 . The first adhesive film 1091 is located above the first microlens ML1 , and the second adhesive film 1092 is located above the second microlens ML2 .

[0089] In another embodiment, if a sacrificial material layer is formed above the microlens layer, after a sacrificial layer opening is formed on the sacrificial material layer, the sacrificial layer opening is used to expose the first microlens ML1.

[0090] Step S405 , forming a first anti-reflection material layer, the first anti-reflection material layer includes a first anti-reflection layer and a first anti-reflection film layer to be removed, the first anti-reflection film layer to be removed is located above the sacrificial layer, and the first anti-reflection layer is located above the first adhesive film.

[0091] In this step, if Fig. 9 As shown, a chemical vapor deposition process can be used to form a first anti-reflection material layer 18, and the first anti-reflection material layer 18 includes a first anti-reflection layer 108 and a first anti-reflection film layer 113 to be removed. The first anti-reflection film layer 113 to be removed is located above the sacrificial layer 110, and the first anti-reflection layer 108 is located above the first adhesive film 1091.

[0092] In another embodiment, if a sacrificial material layer is formed above the microlens layer, after a sacrificial layer opening is formed on the sacrificial material layer, the sacrificial layer opening is used to expose the first microlens ML1, and after the first anti-reflection material layer is formed, the first anti-reflection material layer includes a first anti-reflection layer and a first anti-reflection film layer to be removed, the first anti-reflection film layer to be removed is located above the sacrificial layer, and the first anti-reflection layer is located above the first microlens ML1.

[0093] Step S406 , forming a second adhesion layer and a fourth adhesion layer on the first anti-reflection material layer, wherein the second adhesion layer is located on the first anti-reflection layer, and the fourth adhesion layer is located on the first anti-reflection film layer to be removed.

[0094] In this step, if Fig.10 As shown, a second adhesion layer 111 and a fourth adhesion layer 114 can be formed on the first anti-reflection material layer by a spin coating process, the second adhesion layer 111 is located on the first anti-reflection layer 108, and the fourth adhesion layer 114 is located on the first anti-reflection film layer to be removed 113. The second adhesion layer 111 and the fourth adhesion layer 114 are similar to the first adhesion layer 109, and are not described in detail here.

[0095] Step S407, forming a second anti-reflection material layer above the second adhesion layer and the fourth adhesion layer, the second anti-reflection material layer includes a second anti-reflection layer and a second anti-reflection film layer to be removed, the second anti-reflection layer is located above the second adhesion layer, and the second anti-reflection film layer to be removed is located above the fourth adhesion layer.

[0096] In this step, if Fig.11 As shown, a second anti-reflective material layer 19 can be formed above the second adhesion layer 111 and the fourth adhesion layer 114 by a spin coating process. The second anti-reflective material layer 19 includes a second anti-reflective layer 112 and a second anti-reflective film layer to be removed 115. The second anti-reflective layer 112 is located above the second adhesion layer 111, and the second anti-reflective film layer to be removed 115 is located above the fourth adhesion layer 115.

[0097] Step S408 , peeling off the sacrificial layer, the first anti-reflection film layer to be removed, the second anti-reflection film layer to be removed, and the fourth adhesive layer to obtain an image sensor.

[0098] In this step, the sacrificial layer 110, the first anti-reflective film layer 113 to be removed, the fourth adhesion layer 114 and the second anti-reflective film layer 115 to be removed can be stripped by a stripping process to obtain an image sensor, that is, the sacrificial layer 110 contacting the first adhesion layer 109 is dissolved by a chemical reaction between the stripping liquid and the sacrificial layer 110, and then the dissolved substance is removed by pure water and dried by high-speed rotation, and then the remaining sacrificial layer 110 above the entire pixel area 100 and the first anti-reflective film layer 113 to be removed, the fourth adhesion layer 114 and the second anti-reflective film layer 115 to be removed thereon are stripped.

[0099] In this embodiment, the stripping solution may be a mixture of DMSO (dimethyl sulfoxide) and NMP (N-methyl-2-pyrrolidone), which has the ability to dissolve a variety of compounds. In other embodiments, the stripping solution may also be other materials.

[0100] In the present embodiment, when the sacrificial layer 110 and the first anti-reflection film layer to be removed 113, the fourth adhesive layer 114 and the second anti-reflection film layer to be removed 115 thereon are peeled off, the first adhesive layer 109 can prevent the first anti-reflection layer 108, the second adhesive layer 111 and the second anti-reflection layer 112 above the first filter unit from being peeled off, and the first anti-reflection layer 108, the second adhesive layer 111 and the second anti-reflection layer 112 are successfully retained above the first filter unit, thereby achieving the purpose of increasing the optical efficiency of the first filter unit alone.

[0101] In this embodiment, a sacrificial material layer is formed on the first adhesion layer, and a sacrificial layer opening is formed on the sacrificial material layer to obtain the sacrificial layer, wherein the sacrificial layer opening is used to expose the first adhesion film, and then a first anti-reflection material layer is formed, wherein the first anti-reflection material layer includes a first anti-reflection layer and a first anti-reflection film layer to be removed, the first anti-reflection film layer to be removed is located on the sacrificial layer, and the first anti-reflection layer is located on the first adhesion film, and then a second adhesion layer and a fourth adhesion layer are formed on the first anti-reflection material layer, the second adhesion layer is located on the first anti-reflection layer, and the fourth adhesion layer is located on the first anti-reflection film layer to be removed, and then a second anti-reflection material layer is formed on the second adhesion layer and the fourth adhesion layer, wherein the second anti-reflection material layer includes a first anti-reflection layer and a ... The second anti-reflection layer and the second anti-reflection film layer to be removed, the second anti-reflection layer is located above the second adhesion layer, the second anti-reflection film layer to be removed is located above the fourth adhesion layer, and finally, the sacrificial layer is peeled off and the first anti-reflection film layer to be removed, the second anti-reflection film layer to be removed and the fourth adhesion layer are peeled off together to obtain the image sensor. In this way, it is achieved that two anti-reflection layers are prepared only above the first filter unit, that is, it is possible to prepare two anti-reflection layers in a targeted manner above one or part of the filter units in the filter layer, which can further improve the optical efficiency of one or part of the filter units separately, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0102] Another exemplary embodiment of the present application also provides a method for preparing an image sensor. The method for preparing an image sensor in this embodiment is used to prepare Figure 3 The image sensor shown. Fig.12 As shown, in this embodiment, the method for preparing the image sensor may include the following steps S1201 to S1207: Step S1201, providing a semiconductor device, the semiconductor device comprising a substrate, array-arranged photosensitive elements, a filter layer and a microlens layer, the photosensitive elements are located above the substrate, the filter layer is located above the photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; the microlens layer is located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit.

[0103] This step is similar to the above-mentioned step S401 and will not be described again here.

[0104] Step S1202, forming a first anti-reflection layer above the microlens layer; the first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens.

[0105] In this step, if Fig.13 As shown, a whole first anti-reflection layer 108 can be formed on the microlens layer by chemical vapor deposition process; the first anti-reflection layer 108 includes a first sub-anti-reflection film 1081 and a second sub-anti-reflection film 1082, the first sub-anti-reflection film 1081 is located above the first microlens ML1, and the second sub-anti-reflection film 1082 is located above the second microlens ML2.

[0106] Step S1203, forming a first adhesive layer on the first anti-reflection layer; the first adhesive layer includes a first adhesive film, and the first adhesive film is located on the first sub-anti-reflection film.

[0107] In this step, if Fig.14 As shown, a first adhesion layer 109 can be formed on top of the first anti-reflection layer by a spin coating process; the first adhesion layer 109 includes a first adhesion film 1091 and a second adhesion film 1092, the first adhesion film 1091 is located above the first sub-anti-reflection film 1081, and the second adhesion film 1092 is located above the second sub-anti-reflection film 1082.

[0108] Step S1204 , forming a sacrificial material layer on the first adhesion layer.

[0109] In this embodiment, the distance is described by taking the example that the material of the sacrificial material layer includes positive photoresist.

[0110] In this embodiment, a sacrificial material layer may be formed on the first adhesion layer 109 by using a spin coating process, and the sacrificial material layer covers the entire pixel region 100 .

[0111] In another embodiment, if the first adhesion layer 109 is not formed over the microlens layer, a sacrificial material layer may be formed over the microlens layer.

[0112] Step S1205 , after forming a sacrificial layer opening on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesive film.

[0113] This step is similar to the above-mentioned step S404 and will not be described in detail here.

[0114] Step S1206, forming a second anti-reflection material layer, the second anti-reflection material layer includes a second anti-reflection layer and a second anti-reflection film layer to be removed, the second anti-reflection layer is located above the first adhesive film, and the second anti-reflection film layer to be removed is located above the sacrificial layer.

[0115] In this step, if Fig.15 As shown, a spin coating process can be used to form the second anti-reflective material layer 19, which includes a second anti-reflective layer 112 and a second anti-reflective film layer 115 to be removed. The second anti-reflective layer 112 is located above the first adhesive film 1091, and the second anti-reflective film layer 115 to be removed is located above the sacrificial layer 110.

[0116] In another embodiment, if a sacrificial material layer is formed above the first anti-reflection layer, after a sacrificial layer opening is formed on the sacrificial material layer, the sacrificial layer opening is used to expose the first sub-anti-reflection film, and after the second anti-reflection material layer is formed, the second anti-reflection material layer includes a second anti-reflection layer and a second anti-reflection film layer to be removed, the second anti-reflection film layer to be removed is located above the sacrificial layer, and the second anti-reflection layer is located above the first sub-anti-reflection film.

[0117] Step S1207 , peeling off the sacrificial layer and the second anti-reflection film layer to be removed to obtain an image sensor.

[0118] This step is similar to the above-mentioned step S408 and will not be described again here.

[0119] In this embodiment, a first anti-reflection layer is formed above the microlens layer, the first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens, then a first adhesion layer is formed above the first anti-reflection layer, the first adhesion layer includes a first adhesion film, the first adhesion film is located above the first sub-anti-reflection film, then a sacrificial material layer is formed above the first adhesion layer, then a sacrificial layer opening is formed on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesion film, then a second anti-reflection material layer is formed, the second anti-reflection material layer includes a second anti-reflection layer and a second anti-reflection film layer to be removed, the second anti-reflection layer is located above the first adhesion film, and the second anti-reflection film layer to be removed is located above the sacrificial layer, and finally, the sacrificial layer and the second anti-reflection film layer to be removed are peeled off to obtain an image sensor. In this way, not only is it possible to prepare an anti-reflection layer above the filter layer to improve the optical efficiency of the filter layer, but it is also possible to prepare an anti-reflection layer only above the first filter unit to independently and further improve the optical efficiency of the first filter unit, thereby improving the color accuracy of the collected image, avoiding color imbalance, improving the signal-to-noise ratio of the image, and avoiding the problem of imbalance in brightness and contrast of the image.

[0120] In the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0121] The above description of the embodiments is to facilitate those skilled in the art to understand and apply the present application. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to pay creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the contents disclosed in the present application without departing from the scope and spirit of the present application are within the scope of the present application.

Claims

1. An image sensor, characterized in that: include: substrate; Photosensitive elements arranged in an array are located above the substrate; A filter layer is located above the photosensitive element; the filter layer includes a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; a microlens layer, located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit; At least two stacked anti-reflection layers are located above the first microlens and are used to reduce the reflectivity of light within the first wavelength band.

2. The image sensor according to claim 1, wherein: In the direction from the substrate to the photosensitive element, the refractive index of the anti-reflection layer decreases successively.

3. The image sensor according to claim 2, wherein: comprising a first anti-reflection layer and a second anti-reflection layer stacked, wherein the first anti-reflection layer is located above the first microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The refractive index of the first anti-reflection layer to visible light is 1.4-1.5, the refractive index of the second anti-reflection layer to visible light is 1.25-1.26, and the wavelength range of visible light is 400-700 nm.

4. The image sensor according to claim 3, wherein: Also includes a first adhesive layer and a second adhesive layer; The first adhesion layer is located above the first microlens, the first anti-reflection layer is located above the first adhesion layer, the second adhesion layer is located above the first anti-reflection layer, and the second anti-reflection layer is located above the second adhesion layer.

5. The image sensor according to claim 3, wherein: Also comprising a first adhesive layer; The first anti-reflection layer is also located above the second microlens, and the first adhesion layer is located above the first anti-reflection layer; The first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens; The first adhesive layer includes a first adhesive film and a second adhesive film, the first adhesive film is located above the first sub-anti-reflection film, and the second adhesive film is located above the second sub-anti-reflection film; The second anti-reflection layer is located on the first adhesive film.

6. A method for preparing an image sensor, characterized in that: include: A semiconductor device is provided, the semiconductor device comprising a substrate, array-arranged photosensitive elements, a filter layer and a microlens layer, the photosensitive elements are located above the substrate, the filter layer is located above the photosensitive elements, the filter layer comprises a first filter unit and a second filter unit, the first filter unit is used to transmit light within a first wavelength range, and the second filter unit is used to transmit light within a second wavelength range; the microlens layer is located above the filter layer; the microlens layer comprises a first microlens and a second microlens, the first microlens is located above the first filter unit, and the second microlens is located above the second filter unit; At least two stacked anti-reflection layers are formed above the first microlens, and the anti-reflection layers are used to reduce the reflectivity of light within the first wavelength band.

7. The method for preparing an image sensor according to claim 6, wherein: The image sensor comprises a first anti-reflection layer and a second anti-reflection layer stacked together, wherein the first anti-reflection layer is located above the first microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The at least two stacked anti-reflection layers are formed above the first microlens, comprising: forming a sacrificial material layer, wherein the sacrificial material layer is located above the microlens layer; forming a sacrificial layer opening on the sacrificial material layer to obtain a sacrificial layer; the sacrificial layer opening is used to expose the first microlens; forming a first anti-reflection material layer, wherein the first anti-reflection material layer comprises a first anti-reflection layer and a first anti-reflection film layer to be removed, wherein the first anti-reflection film layer to be removed is located above the sacrificial layer, and the first anti-reflection layer is located above the first microlens; forming a second anti-reflection material layer, wherein the second anti-reflection material layer comprises a second anti-reflection layer and a second anti-reflection film layer to be removed, wherein the second anti-reflection film layer to be removed is located above the first anti-reflection film layer to be removed, and the second anti-reflection layer is located above the first anti-reflection layer; The sacrificial layer, the first anti-reflection film layer to be removed, and the second anti-reflection film layer to be removed are peeled off to obtain the image sensor.

8. The method for preparing an image sensor according to claim 7, wherein: Before forming the sacrificial material layer, the method further comprises: forming a first adhesive layer above the microlens layer; the first adhesive layer comprises a first adhesive film, and the first adhesive film is located above the first microlens; The forming of the sacrificial material layer comprises: forming the sacrificial material layer above the first adhesion layer; After forming a sacrificial layer opening on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesive film; After forming the first anti-reflection material layer, the first anti-reflection layer is located above the first adhesive film, and the first anti-reflection film layer to be removed is located above the sacrificial layer; Before forming the second anti-reflection material layer, the method further comprises: forming a second adhesion layer and a fourth adhesion layer on the first anti-reflection material layer, wherein the second adhesion layer is located on the first anti-reflection layer, and the fourth adhesion layer is located on the first anti-reflection film layer to be removed; After forming the second anti-reflection material layer, the second anti-reflection layer is located above the second adhesion layer, and the second anti-reflection film layer to be removed is located above the fourth adhesion layer; When the sacrificial layer, the first anti-reflection film layer to be removed, and the second anti-reflection film layer to be removed are peeled off, the fourth adhesive layer is also peeled off.

9. The method for preparing an image sensor according to claim 6, wherein: The image sensor comprises a first anti-reflection layer and a second anti-reflection layer stacked, the first anti-reflection layer is located above the first microlens and the second microlens, and the second anti-reflection layer is located above the first anti-reflection layer; The at least two stacked anti-reflection layers are formed above the first microlens, comprising: The first anti-reflection layer is formed above the microlens layer; the first anti-reflection layer includes a first sub-anti-reflection film and a second sub-anti-reflection film, the first sub-anti-reflection film is located above the first microlens, and the second sub-anti-reflection film is located above the second microlens; forming a sacrificial material layer; the sacrificial material layer is located above the first anti-reflection layer; forming a sacrificial layer opening on the sacrificial material layer to obtain a sacrificial layer; the sacrificial layer opening is used to expose the first sub-anti-reflection film; forming a second anti-reflection material layer, wherein the second anti-reflection material layer comprises a second anti-reflection layer and a second anti-reflection film layer to be removed, wherein the second anti-reflection film layer to be removed is located above the sacrificial layer, and the second anti-reflection layer is located above the first sub-anti-reflection film; The sacrificial layer and the second anti-reflection film layer to be removed are peeled off to obtain the image sensor.

10. The method for preparing an image sensor according to claim 9, wherein: Before forming the sacrificial material layer, the method further comprises: forming a first adhesive layer on the first anti-reflection layer; the first adhesive layer comprises a first adhesive film, and the first adhesive film is located on the first sub-anti-reflection film; The forming of the sacrificial material layer comprises: forming the sacrificial material layer above the first adhesion layer; After forming a sacrificial layer opening on the sacrificial material layer, the sacrificial layer opening is used to expose the first adhesive film; After the second anti-reflection material layer is formed, the second anti-reflection layer is located above the first adhesive film, and the second anti-reflection film layer to be removed is located above the sacrificial layer.

Images