Image sensor and electronic device
By designing an inner and outer double-layer light-blocking structure in the image sensor, the optical crosstalk problem between large pixels and small pixels is solved, and the imaging quality of the image sensor under strong light conditions is improved.
Patent Information
- Application Number
- CN202423179212.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2034-12-20
AI Technical Summary
In existing technologies, optical crosstalk of large pixels in large-pixel structures has a significant impact on small pixels, causing glare during imaging, and there is a lack of effective solutions.
A pixel array is designed in an image sensor, including a central sub-pixel and an edge sub-pixel. The photosensitive area of the edge sub-pixel is larger than that of the central sub-pixel. A double-layer light-blocking structure is set, with a first annular light-blocking part surrounding the central sub-pixel and a second annular light-blocking part surrounding the first annular light-blocking part, in order to reduce optical crosstalk.
The double-layer light-blocking structure effectively reduces optical crosstalk between large pixels and small pixels, improving image quality, especially reducing glare under strong light conditions.
Smart Images
Figure CN223829710U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of semiconductor technology and relates to an image sensor and a corresponding electronic device. Background Technology
[0002] A light-emitting diode (LED) works based on the electroluminescence effect of semiconductor materials. LEDs typically consist of two semiconductor materials: P-type (with more holes) and N-type (with more electrons). A PN junction is formed at the interface between these two materials. When current flows through the LED, electrons and holes are injected into the PN junction region. Electrons flow from the N-type material to the P-type material, and vice versa. In the PN junction region, electrons and holes meet and recombine, meaning electrons fill the holes. This recombination process releases energy, typically in the form of photons—light. The wavelength (color) of the light emitted by an LED depends on the band gap of the semiconductor materials. Different combinations of semiconductor materials can produce different wavelengths of light, thus producing different colors. The efficiency and brightness of an LED depend on various factors, including the quality of the semiconductor materials, the design of the PN junction, the current applied, and the LED's packaging method. Due to their high efficiency, long lifespan, small size, and tunable brightness, LEDs are widely used in lighting, displays, communications, and many other fields. In automotive applications, large and small pixel structure image sensors can be used due to the need for a greater dynamic range.
[0003] A wider dynamic range can cover the flicker frequency of LEDs. By dividing the sensor area of a pixel into two parts, a larger pixel and a smaller pixel, larger pixels can be used in low-light conditions to collect more photons, while smaller pixels can be used in bright light conditions to avoid premature saturation, thus expanding the dynamic range. However, this inevitably leads to a significant difference in sensitivity between large and small pixels. Optical crosstalk from large pixels has a much greater impact on small pixels compared to products with normal pixels. Ordinary small pixels cannot effectively reduce optical crosstalk from large pixels, especially when there are strong light areas in the small photodiode (SPD), resulting in noticeable flare during imaging. Currently, there is no good solution to this problem.
[0004] Therefore, how to provide an image sensor and electronic device that reduces optical crosstalk between large and small pixels has become an important technical problem that needs to be solved by those skilled in the art.
[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Utility Model Content
[0006] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide an image sensor and electronic device to solve the problem that the optical crosstalk of large pixels has a greater impact on small pixels in the existing large and small pixel structure technology.
[0007] To achieve the above and other related objectives, this utility model provides an image sensor, including a pixel array, wherein the pixel array includes a plurality of pixel units arranged in an array, and each pixel unit includes:
[0008] Central sub-pixel;
[0009] At least one edge sub-pixel is located outside the center sub-pixel, and the photosensitive area of the edge sub-pixel is larger than that of the center sub-pixel;
[0010] The light-blocking structure includes a first annular light-blocking part and a second annular light-blocking part. The first annular light-blocking part is disposed around the central sub-pixel, and the second annular light-blocking part is disposed around the first annular light-blocking part.
[0011] Optionally, the pixel unit includes a plurality of edge sub-pixels evenly distributed around the central sub-pixel, and the light-blocking structure further includes a light-blocking strip located between two adjacent edge sub-pixels, one end of which is connected to the second annular light-blocking portion.
[0012] Optionally, the light-blocking strip is linear, and the extension line of the light-blocking strip passes through the center line of the central sub-pixel.
[0013] Optionally, the first annular light-blocking portion is a polygonal ring or a circular ring, and the second annular light-blocking portion is a polygonal ring or a circular ring.
[0014] Optionally, the center of the second annular light-blocking portion is located on the center line of the center sub-pixel.
[0015] Optionally, the center of the first annular light-blocking portion is located on the center line of the center sub-pixel, or the center of the first annular light-blocking portion of at least one of the pixel units in the pixel array is offset from the center line of the center sub-pixel.
[0016] Optionally, the center of the first annular light-blocking portion of at least one of the pixel units in the pixel array is offset from the center line of the central sub-pixel in a direction toward the center line of the pixel array.
[0017] Optionally, the top end of the first annular light-blocking portion is flush with the top end of the second annular light-blocking portion, or the top end of the first annular light-blocking portion is higher than the top end of the second annular light-blocking portion.
[0018] Optionally, the ratio of the photosensitive area of the edge sub-pixel to the photosensitive area of the center sub-pixel is between (3-15):1.
[0019] Optionally, the first annular light-blocking portion is disposed on the outer edge of the central sub-pixel, and the second annular light-blocking portion is disposed above the edge sub-pixel.
[0020] Optionally, the image sensor includes a photoelectric conversion layer, a light-blocking color filter layer, and a microlens layer arranged sequentially from bottom to top. The central sub-pixel includes a first photodiode located in the photoelectric conversion layer, and the edge sub-pixel includes a second photodiode located in the photoelectric conversion layer. The photosensitive area of the second photodiode is larger than that of the first photodiode, and the light-blocking structure is located in the light-blocking color filter layer.
[0021] Optionally, the light-blocking color filter layer includes a light-blocking layer and a color filter layer. The light-blocking layer includes a dielectric layer, the light-blocking structure is embedded in the dielectric layer, and the color filter layer is located on the light-blocking layer and includes multiple color filters.
[0022] Optionally, the light-blocking color filter layer includes a dielectric layer and a plurality of color filters, wherein the light-blocking structure and the color filters are both embedded in the dielectric layer.
[0023] This invention also provides an electronic device, including an image sensor as described in any of the above embodiments.
[0024] As described above, the image sensor of this invention includes a pixel array, which comprises multiple pixel units arranged in an array. Each pixel unit includes a central sub-pixel, a light-blocking structure, and at least one edge sub-pixel. The edge sub-pixel is located around the central sub-pixel, and its photosensitive area is larger than that of the central sub-pixel. In other words, the central sub-pixel constitutes a small pixel, and the edge sub-pixel constitutes a large pixel, together forming a large and small pixel structure. The light-blocking structure includes a first annular light-blocking portion surrounding the central sub-pixel and a second annular light-blocking portion surrounding the first annular light-blocking portion. Because the small pixel has two rings of light-blocking portions around it, more optical crosstalk from the large pixel can be blocked. Ultimately, with a slight sacrifice in the photosensitive area of the large pixel, the optical crosstalk phenomenon from the large pixel to the small pixel can be minimized. The electronic device of this invention includes the above-described image sensor and can acquire high-quality image information. Attached Figure Description
[0025] Figure 1 The diagram shown is a planar structural schematic of the light-blocking structure in an embodiment of the image sensor of this utility model.
[0026] Figure 2 The diagram shows a schematic of the first annular light-blocking part of the light-blocking structure in the image sensor of this utility model, with the center of the light-blocking part offset to the left from the center line of the center sub-pixel.
[0027] Figure 3 The diagram shows a schematic of the center of the first annular light-blocking part of the image sensor of this utility model being offset to the right from the center line of the center sub-pixel.
[0028] Figure 4 Displayed as Figure 1 The structure shown is a cross-sectional view along line A-A'.
[0029] Figure 5 The diagram shown is a cross-sectional view of the light-blocking structure in the image sensor of this invention in some other embodiments.
[0030] Figure 6 The diagram shown is a cross-sectional view of the image sensor of this invention in one embodiment.
[0031] Figure 7 The diagram shows the structure obtained after the first dielectric layer is formed on the substrate.
[0032] Figure 8 The diagram shows the structure obtained after forming the first annular trench in the first dielectric layer.
[0033] Figure 9 The diagram shows the structure obtained after filling the first annular groove with light-blocking material to obtain the second annular light-blocking section.
[0034] Figure 10 The diagram shows the structure obtained after forming the second annular trench in the first dielectric layer.
[0035] Figure 11 The diagram shows the structure obtained after filling the second annular groove with light-blocking material to obtain the first annular light-blocking section.
[0036] Figure 12 Displayed as in Figure 11 A schematic diagram of the structure obtained after further deposition of a second dielectric layer on the structure shown.
[0037] Figure 13 This is a schematic diagram of the structure obtained after forming the third annular trench in the second dielectric layer.
[0038] Figure 14 The diagram shows the structure obtained after filling the third annular groove with light-blocking material.
[0039] Explanation of reference numerals in the attached figures
[0040] 1. Light-blocking structure
[0041] 101 First annular light-blocking part
[0042] 102 Second annular light-blocking part
[0043] 103 Light-blocking strip
[0044] 2 Photoelectric conversion layer
[0045] 3-block color filter layer
[0046] 301 Light-blocking layer
[0047] 3011 Dielectric Layer
[0048] 3011a First Dielectric Layer
[0049] 3011b Second Dielectric Layer
[0050] 302 color filter layer
[0051] 4. Microlens layer
[0052] 5 First annular groove
[0053] 6 Second annular groove
[0054] 7 Third annular groove Detailed Implementation
[0055] Optical crosstalk between large and small pixels is very significant. In actual images, flare can still occur due to the influence of large pixels on small pixels, resulting in a washed-out appearance or halo effect caused by strong light. This invention provides an image sensor and electronic device that can reduce optical crosstalk between large and small pixels.
[0056] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.
[0057] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.
[0058] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0059] In the detailed description of the embodiments of this utility model, for ease of explanation, the schematic diagrams illustrating the device structure may be partially enlarged without adhering to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of this utility model. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.
[0060] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.
[0061] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.
[0062] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0063] In some embodiments of this utility model, an image sensor is provided, the image sensor including a pixel array, the pixel array including a plurality of pixel units arranged in an array.
[0064] As an example, the arrangement of the pixel array can be designed according to different application scenarios and requirements. For example, it can adopt Bayer arrangement (for four groups of 2×2 pixels in a 4×4 pixel array, the four pixels in each group are assigned filters according to red-green-green-blue (RGGB), Quad-Bayer arrangement (each group of 2×2 pixels in a 4×4 pixel array is assigned an RGGB filter), Nano-Cell arrangement (nine-in-one arrangement), Hex-Bayer arrangement (sixteen-in-one arrangement) or other suitable arrangements.
[0065] Specifically, the pixel unit includes a central sub-pixel, a light-blocking structure, and at least one edge sub-pixel. The edge sub-pixel is located around the central sub-pixel, and its photosensitive area is larger than that of the central sub-pixel. In other words, the central sub-pixel constitutes a small pixel, and the edge sub-pixel constitutes a large pixel; together, they form a large-small pixel structure. It should be noted that "center" and "edge" here do not strictly define the actual physical locations of the large and small pixels within the pixel unit. The purpose here is to illustrate that a pixel unit defined here has a small pixel and at least one large pixel, i.e., a central sub-pixel and at least one edge sub-pixel. The actual physical locations and numbers can be designed according to actual needs. For the entire pixel array comprising multiple pixel units arranged in an array, the central sub-pixel is surrounded by at least one edge sub-pixel. In this case, the central sub-pixel can be considered to be located at the center of the edge sub-pixels.
[0066] As an example, each pixel unit may contain one or more edge sub-pixels. When the same center sub-pixel is surrounded by multiple edge sub-pixels, each edge sub-pixel may belong to only one pixel unit or may be shared by multiple pixel units.
[0067] Specifically, this invention sets up an inner and outer double-layer light-blocking structure in the large and small pixel structure to block optical crosstalk from the large pixels. Compared with a single-layer light-blocking structure, it has a better blocking effect and can weaken the glare caused by strong light as much as possible, so that the image can reproduce the real scene as much as possible.
[0068] For example, please refer to Figure 1 The image sensor of this invention is shown as a planar structural schematic diagram of the light-blocking structure 1 in one embodiment, which includes a first annular light-blocking part 101 and a second annular light-blocking part 102. The first annular light-blocking part 101 is disposed around the central sub-pixel (not shown), and the second annular light-blocking part 102 is disposed around the first annular light-blocking part 101.
[0069] It should be noted that, in the pixel unit, the edge sub-pixels use larger photodiodes with a larger photosensitive area, which can be used under low light conditions to collect more photons. The center sub-pixels use smaller photodiodes with a smaller photosensitive area, which can be used under bright light conditions to avoid excessive saturation. The photosensitive areas of the center sub-pixels and the edge sub-pixels can be designed according to the dynamic range required by the device, and are not limited in this invention.
[0070] As an example, the first annular light-blocking portion is disposed at the outer edge of the central sub-pixel, and the second annular light-blocking portion is disposed above the edge sub-pixel. If the area of each pixel unit cannot be further increased, it is preferable to slightly sacrifice the photosensitive area of the edge sub-pixel to improve the single-layer light-blocking structure into an inner and outer double-layer light-blocking structure. That is, the photosensitive area of the original central sub-pixel can be kept unchanged, and the inner edge of the original edge sub-pixel can be appropriately moved outward to add a ring of light-blocking portion in the newly added space. In this way, the photosensitive area of the large pixel is slightly sacrificed to minimize the optical crosstalk phenomenon of the large pixel to the small pixel. It should be noted that the first annular light-blocking portion being disposed on the outer edge of the central sub-pixel means that the central sub-pixel has an outer edge in the semiconductor substrate, and the first annular light-blocking portion is disposed on the semiconductor substrate and corresponding to this outer edge. The second annular light-blocking portion being disposed above the edge sub-pixel means that the edge sub-pixel has a corresponding region in the semiconductor substrate, and the second annular light-blocking structure is located above the region of the semiconductor substrate corresponding to the edge sub-pixel. In other words, the region of the edge sub-pixel in the semiconductor substrate remains unchanged, and the second annular light-blocking structure is located above this region.
[0071] As an example, the ratio of the photosensitive area of the edge sub-pixel to the photosensitive area of the center sub-pixel is between (3-15):1, for example, it can be 4:1, 5:1 or 10:1, etc.
[0072] As an example, the first annular light-blocking portion 101 can be a polygonal ring, a circular ring, or other suitable shape selected according to the contours and layout of the center sub-pixel and the edge sub-pixels. The second annular light-blocking portion 102 can be a polygonal ring, a circular ring, or other suitable shape selected according to the contours and layout of the center sub-pixel and the edge sub-pixels. Further, the shape of the first annular light-blocking portion 101 is the same as the shape of the second annular light-blocking portion 102. Figure 1 In the illustrated embodiment, both the first annular light-blocking portion 101 and the second annular light-blocking portion 102 are square. For the central sub-pixel surrounded by the first annular light-blocking portion 102, four edge sub-pixels are arranged adjacent to it. Furthermore, the shape of the first annular light-blocking portion 101 can be configured to be the same as the outer edge shape of the photosensitive doping region of the corresponding small pixel.
[0073] As an example, when the pixel unit includes a plurality of edge sub-pixels evenly distributed around the central sub-pixel, the light-blocking structure 1 further includes a light-blocking strip 103 located between two adjacent edge sub-pixels, one end of which is connected to the second annular light-blocking portion 102. In one implementation, each light-blocking strip 103 and each of the second annular light-blocking portions 102 are connected to form a mesh structure of the corresponding pixel array.
[0074] As an example, the light-blocking strip 103 is straight, and the extension line of the light-blocking strip 103 passes through the center line of the center sub-pixel.
[0075] In some embodiments, the center of the second annular light-blocking portion 102 and the center of the first annular light-blocking portion 101 of each pixel unit in the pixel array are both located on the center line of the corresponding center sub-pixel.
[0076] It should be noted that for multiple pixel units in the pixel array, the incident angle of incident light obtained by pixel units located in different regions of the pixel array may be different. In order to better improve the optical crosstalk phenomenon of large pixels to small pixels, in some embodiments, the center of the second annular light-blocking part 102 of each pixel unit in the pixel array may be set to be located on the center line of the corresponding central sub-pixel, and the center of the first annular light-blocking part 101 of at least one pixel unit in the pixel array may be set to deviate from the center line of the central sub-pixel, for example, deviating from the center line of the central sub-pixel in the direction of the center line of the pixel array, so as to better adapt to the incident direction of light and achieve a better anti-optical crosstalk effect in different regions. Furthermore, the farther away a pixel is from the pixel array, the greater the deviation distance from the center line of the central sub-pixel.
[0077] As an example, in some embodiments, the pixel array is divided into a central region and an edge region according to a preset rule. For a pixel unit located in the central region, the center of the first annular light-blocking part 101 is positioned on the center line of the corresponding central sub-pixel. For a pixel unit located in the edge region, the center of the first annular light-blocking part 101 is offset from the center line of the corresponding central sub-pixel. For example, when the pixel unit is located in the right region of the pixel array (the center of the pixel array is to the left of the pixel unit), the center of the first annular light-blocking part 101 is offset to the left from the center line of the central sub-pixel. When the pixel unit is located in the left region of the pixel array (the center of the pixel array is to the right of the pixel unit), the center of the first annular light-blocking part 101 is offset to the right from the center line of the central sub-pixel, and so on, so that the light-blocking structure in different regions has the best light-blocking effect. The preset rule can be set according to photosensitive requirements and actual incident light conditions.
[0078] For example, please refer to Figure 2 and Figure 3 ,in, Figure 2 The diagram shows the center of the first annular light-blocking portion 101 offset to the left from the center line of the central sub-pixel. Figure 3 The diagram shows the center of the first annular light-blocking portion 101 offset to the right from the center line of the central sub-pixel.
[0079] For example, please refer to Figure 4 Displayed as Figure 1 The schematic diagram of the cross-sectional structure along line A-A' shows that the top end of the first annular light-blocking part 101 is flush with the top end of the second annular light-blocking part 102.
[0080] For example, please refer to Figure 5 The diagram shows a cross-sectional view of the light-blocking structure in some other embodiments. The top of the first annular light-blocking part 101 is higher than the top of the second annular light-blocking part 102. By adjusting the height difference between the first annular light-blocking part 101 and the second annular light-blocking part 102, the anti-optical crosstalk effect can be optimized while taking into account the photosensitivity effect. Based on the height difference setting, the light entering the edge sub-pixel can be reduced by the blocking effect of the second annular light-blocking part 102. In particular, in a further example, when the second annular light-blocking part is located above the semiconductor substrate region corresponding to the edge sub-pixel, the influence of the second annular light-blocking part on the photosensitivity effect can be mitigated based on the height difference setting.
[0081] For example, please refer to Figure 6 The diagram shows a cross-sectional view of the image sensor in one embodiment, comprising a photoelectric conversion layer 2, a light-blocking color filter layer 3, and a microlens layer 4 arranged sequentially from bottom to top. The central sub-pixel includes a first photodiode (not shown) located in the photoelectric conversion layer 2, and the edge sub-pixel includes a second photodiode (not shown) located in the photoelectric conversion layer 2. The photosensitive area of the second photodiode is larger than that of the first photodiode. The first and second photodiodes are used to capture light. The light-blocking structure 1 is located in the light-blocking color filter layer 3 to reduce optical crosstalk between large and small pixels. The light-blocking color filter layer 3 also has a color filter for separating the red, green, and blue (RGB) components of reflected light. The microlens layer 4 has microlenses for collecting light from inactive parts of the CIS and focusing it onto the photodiode.
[0082] As an example, in Figure 6 In the embodiment shown, the light-blocking color filter layer 3 includes a light-blocking layer 301 and a color filter layer 302. The light-blocking layer 301 includes a dielectric layer 3011. The light-blocking structure 1 is embedded in the dielectric layer 3011. The color filter layer 302 is located on the light-blocking layer 301 and includes multiple color filters.
[0083] It should be pointed out that, in Figure 6 In the illustrated embodiment, the light-blocking structure 1 and the color filter are not on the same plane. The color filter is located in the film layer above the light-blocking structure 3. However, in some other embodiments, the light-blocking structure 1 and the color filter may also be located on the same plane. For example, the light-blocking color filter layer includes a dielectric layer and multiple color filters, and the light-blocking structure 3 and the color filters are both embedded in the dielectric layer.
[0084] As an example, the material of the light-blocking structure 3 includes tungsten and / or other suitable light-blocking materials.
[0085] The following describes a manufacturing process for the image sensor of this utility model, including the following steps:
[0086] S1: A substrate is provided, the substrate including a photoelectric conversion layer;
[0087] S2: Form a light-blocking color filter layer on the substrate;
[0088] S3: Form a microlens layer on the light-blocking color filter layer.
[0089] For example, please refer to Figures 7 to 11 The diagram shows a structural schematic obtained from some steps in forming a light-blocking color filter layer on the substrate in one embodiment.
[0090] Specifically, such as Figure 7 The diagram shows a schematic of the structure obtained after forming a first dielectric layer 3011a on a substrate (not shown) using chemical vapor deposition, physical vapor deposition or other suitable methods. The first dielectric layer 3011a may be made of silicon dioxide or other suitable materials.
[0091] Specifically, such as Figure 8 The diagram shows a schematic of the structure obtained after forming a first annular trench 5 in the first dielectric layer 3011a using photolithography, etching, or other suitable processes. The first annular trench 5 can be a polygonal ring, a circular ring, or other suitable shapes selected according to the contours and layout of the central sub-pixel and the edge sub-pixel.
[0092] Specifically, such as Figure 9 The diagram shows a schematic of the structure obtained after filling the first annular trench 5 with a light-blocking material using chemical vapor deposition, physical vapor deposition, or other suitable methods to obtain the second annular light-blocking portion 102. The light-blocking material may include tungsten and / or other suitable light-blocking materials.
[0093] Specifically, such as Figure 10 The diagram shows a schematic of the structure obtained after forming a second annular trench 6 in the first dielectric layer 3011a using photolithography, etching, or other suitable processes. The second annular trench 6 is located in the area enclosed by the first annular trench 5. The second annular trench 6 can be a polygonal ring, a circular ring, or other suitable shapes selected according to the contours and layout of the central sub-pixel and the edge sub-pixel.
[0094] Specifically, such as Figure 11The diagram shows a schematic of the structure obtained after filling the second annular trench 6 with a light-blocking material using chemical vapor deposition, physical vapor deposition, or other suitable methods to obtain the first annular light-blocking portion 101. The light-blocking material may include tungsten and / or other suitable light-blocking materials.
[0095] Thus, a light-blocking structure 1 is obtained. In the light-blocking structure 1, the top end of the first annular light-blocking part 101 is flush with the top end of the second annular light-blocking part 102. The step of forming a color filter can be further performed. The color filter can be formed on the same plane as the light-blocking structure 1, or it can be formed in a film layer above the light-blocking structure 1. For example, in one embodiment, multiple color filters are formed in the first dielectric layer 3011a. In another embodiment, a color filter layer is formed above the first dielectric layer. The color filter layer includes multiple color filters. The process of forming the color filter is well known to those skilled in the art and will not be described in detail here.
[0096] It should be pointed out that, in Figures 7 to 11 In the illustrated embodiment, the first annular light-blocking portion 101 and the second annular light-blocking portion 102 of the light-blocking structure 1 are formed separately, resulting in a more stable pattern and higher reliability. However, in other embodiments, the first annular light-blocking portion 101 and the second annular light-blocking portion 102 can also be formed simultaneously as needed. For example, in one embodiment, forming the light-blocking color filter layer on the substrate includes the following steps:
[0097] (1) A first dielectric layer is formed on the substrate by chemical vapor deposition, physical vapor deposition or other suitable methods;
[0098] (2) A first annular trench and a second annular trench are simultaneously formed in the first dielectric layer using photolithography, etching or other suitable processes, wherein the second annular trench is located in the area enclosed by the first annular trench;
[0099] (3) A light-blocking material is filled in the first annular trench and the second annular trench using chemical vapor deposition, physical vapor deposition or other suitable methods, wherein the light-blocking material filled in the first annular trench constitutes the second annular light-blocking part, and the light-blocking material filled in the second annular trench constitutes the first annular light-blocking part.
[0100] It should be pointed out that, in Figures 7 to 11In the illustrated embodiment or the embodiment described above where the first annular light-blocking portion and the second annular light-blocking portion are formed simultaneously, the top end of the first annular light-blocking portion 101 of the light-blocking structure 1 is flush with the top end of the second annular light-blocking portion 102. However, in other embodiments, the top end of the first annular light-blocking portion 101 may be higher than the top end of the second annular light-blocking portion 102. In this case, it is also necessary to... Figure 11 Based on the structure shown, the following steps are performed further.
[0101] For details, please refer to Figure 12 Displayed as in Figure 11 The diagram shows the structure obtained after further deposition of the second dielectric layer 3011b on the structure shown. The second dielectric layer 3011b can be made of the same material as the first dielectric layer 3011a.
[0102] For details, please refer to Figure 13 The diagram shows a schematic of the structure obtained after forming a third annular trench 7 in the second dielectric layer 3011b using photolithography, etching or other suitable processes, wherein the third annular trench 7 is aligned with the second annular trench 6.
[0103] For details, please refer to Figure 14 This is shown as filling the third annular groove 7 with light-blocking material so that the top of the first annular light-blocking part 101 is higher than the top of the second annular light-blocking part 102.
[0104] Thus, a light-blocking structure 1 is obtained. In the light-blocking structure 1, the top end of the first annular light-blocking part 101 is higher than the top end of the second annular light-blocking part 102. The step of forming a color filter can be further performed. The color filter can be formed on the same plane as the light-blocking structure 1, or it can be formed in a film layer above the light-blocking structure 1. For example, in one embodiment, multiple color filters are formed in the first dielectric layer 3011a and the second dielectric layer 3011b. In another embodiment, a color filter layer is formed above the second dielectric layer 3011b. The color filter layer includes multiple color filters. The process of forming the color filter is well known to those skilled in the art and will not be described in detail here.
[0105] As an example, when the pixel unit includes a plurality of edge sub-pixels evenly distributed around the central sub-pixel, the light-blocking structure 1 further includes a light-blocking strip 103 located between two adjacent edge sub-pixels. One end of the light-blocking strip 103 is connected to the second annular light-blocking part 102. The light-blocking strip 103 can be manufactured synchronously with the second annular light-blocking part 102.
[0106] This invention also provides an electronic device, including an image sensor as described in any of the above embodiments. The electronic device can be a security monitoring device, vehicle electronics, a mobile phone camera, a machine vision device, etc. The image sensor based on this invention can acquire high-quality image information and can be used in infrared utilization devices.
[0107] In summary, the image sensor of this invention includes a pixel array, which comprises multiple pixel units arranged in an array. Each pixel unit includes a central sub-pixel, a light-blocking structure, and at least one edge sub-pixel. The edge sub-pixels are located around the central sub-pixels, and their photosensitive area is larger than that of the central sub-pixels. In other words, the central sub-pixels constitute small pixels, and the edge sub-pixels constitute large pixels, together forming a large-small pixel structure. The light-blocking structure includes a first annular light-blocking portion surrounding the central sub-pixel and a second annular light-blocking portion surrounding the first annular light-blocking portion. Because the small pixel has two rings of light-blocking portions around it, it can block more optical crosstalk from the large pixel. Ultimately, it can minimize the optical crosstalk between the large and small pixels while slightly sacrificing the photosensitive area of the large pixel. The electronic device of this invention includes the above-mentioned image sensor and can acquire high-quality image information. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.
[0108] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. An image sensor, comprising a pixel array, said pixel array including a plurality of pixel units arranged in an array, characterized in that, Each of the pixel units includes: Central sub-pixel; At least one edge sub-pixel is located outside the center sub-pixel, and the photosensitive area of the edge sub-pixel is larger than that of the center sub-pixel; The light-blocking structure includes a first annular light-blocking part and a second annular light-blocking part. The first annular light-blocking part is disposed around the central sub-pixel, and the second annular light-blocking part is disposed around the first annular light-blocking part.
2. The image sensor according to claim 1, characterized in that: The pixel unit includes a plurality of edge sub-pixels evenly distributed around the central sub-pixel, and the light-blocking structure further includes a light-blocking strip located between two adjacent edge sub-pixels, one end of which is connected to the second annular light-blocking portion.
3. The image sensor according to claim 2, characterized in that: The light-blocking strip is straight, and the extension line of the light-blocking strip passes through the center line of the center sub-pixel.
4. The image sensor according to claim 1, characterized in that: The first annular light-blocking portion is a polygonal ring or a circular ring, and the second annular light-blocking portion is a polygonal ring or a circular ring; and / or, the top end of the first annular light-blocking portion is flush with the top end of the second annular light-blocking portion, or the top end of the first annular light-blocking portion is higher than the top end of the second annular light-blocking portion.
5. The image sensor according to claim 1, characterized in that: The center of the second annular light-blocking part is located on the center line of the center sub-pixel.
6. The image sensor according to claim 5, characterized in that: The center of the first annular light-blocking portion is located on the center line of the center sub-pixel, or the center of the first annular light-blocking portion of at least one of the pixel units in the pixel array is offset from the center line of the center sub-pixel.
7. The image sensor according to claim 6, characterized in that: The center of the first annular light-blocking portion of at least one of the pixel units in the pixel array is offset from the center line of the central sub-pixel in a direction toward the center line of the pixel array.
8. The image sensor according to claim 1, characterized in that: The ratio of the photosensitive area of the edge sub-pixel to the photosensitive area of the center sub-pixel is between (3-15):1; and / or, the first annular light-blocking part is disposed corresponding to the outer edge of the center sub-pixel, and the second annular light-blocking part is disposed correspondingly above the edge sub-pixel.
9. The image sensor according to claim 1, characterized in that: The image sensor includes a photoelectric conversion layer, a light-blocking color filter layer, and a microlens layer arranged sequentially from bottom to top. The central sub-pixel includes a first photodiode located in the photoelectric conversion layer, and the edge sub-pixel includes a second photodiode located in the photoelectric conversion layer. The photosensitive area of the second photodiode is larger than that of the first photodiode, and the light-blocking structure is located in the light-blocking color filter layer.
10. The image sensor according to claim 9, characterized in that: The light-blocking color filter layer includes a light-blocking layer and a color filter layer. The light-blocking layer includes a dielectric layer, and the light-blocking structure is embedded in the dielectric layer. The color filter layer is located on the light-blocking layer and includes multiple color filters; or, the light-blocking color filter layer includes a dielectric layer and multiple color filters, and both the light-blocking structure and the color filters are embedded in the dielectric layer.
11. An electronic device, characterized in that: Including the image sensor as described in any one of claims 1-10.