Image sensor

Abstract

Embodiments of the present application provide an image sensor. The image sensor includes a substrate, first photodiodes, second photodiodes, an intermediate layer, a light guide structure, and a microlens layer. The first photodiodes and the second photodiodes are alternately arranged in the substrate. An area of each of the first photodiodes in a top view is less than an area of each of the second photodiodes. The intermediate layer is disposed on the substrate. The light guide structure is disposed in the intermediate layer and on at least one of the first photodiodes or the second photodiodes. A refractive index of the light guide structure is greater than a refractive index of the intermediate layer. The microlens layer is disposed on the intermediate layer.

Description

Technical Field

[0001] The present invention relates to an image sensor, and more particularly to an image sensor having a light guide structure. Background Technology

[0002] Complementary metal-oxide-semiconductor (CIS) image sensors are widely used in various image capturing devices, such as digital still-image cameras and digital video cameras. The photosensitive portion of an image sensor detects changes in ambient color and generates a signal charge depending on the amount of light received by the photosensitive portion. Furthermore, the signal charge generated in the photosensitive portion can be transmitted and amplified to obtain an image signal.

[0003] Image sensors should be able to acquire images quickly, and their accuracy, spatial resolution, and dynamic range should be as high as possible. However, traditional image sensors suffer from problems such as missing scene details, blurring, or severe distortion due to their limited dynamic range. Therefore, there is still a need for an image sensor capable of achieving high dynamic range (HDR) imaging. Summary of the Invention

[0004] According to some embodiments of the present invention, an image sensor is provided. The image sensor includes a substrate, a first photodiode, a second photodiode, an intermediate layer, a light guide structure, and a microlens layer. The first photodiode and the second photodiode are alternately disposed in the substrate. The area of ​​each first photodiode in the top view is smaller than the area of ​​each second photodiode. The intermediate layer is disposed on the substrate. The light guide structure is disposed in the intermediate layer and is disposed above at least one of the first photodiode or the second photodiode. The refractive index of the light guide structure is greater than the refractive index of the intermediate layer. The microlens layer is disposed on the intermediate layer.

[0005] According to some other embodiments of the present invention, another image sensor is also provided. The image sensor includes a substrate, a first photodiode, a second photodiode, an intermediate layer, a light guide structure, a color filter array, and a microlens layer. The first photodiode and the second photodiode are alternately disposed in the substrate. The area of ​​each first photodiode in the top view is smaller than the area of ​​each second photodiode. The intermediate layer is disposed on the substrate. The light guide structure is disposed in the intermediate layer and is disposed above at least one of the first photodiode or the second photodiode. The color filter array has multiple color filters and is disposed on the intermediate layer. The microlens layer is disposed on the color filter array and includes multiple microlenses. Each color filter overlaps with two adjacent microlenses.

[0006] The following embodiments are described in detail with reference to the accompanying drawings. Attached Figure Description

[0007] A more comprehensive understanding of the embodiments of the present invention will be achieved by reading the following detailed description and examples in conjunction with the accompanying drawings, wherein:

[0008] Figures 1A to 1F This is a cross-sectional view of an image sensor according to various embodiments of the present invention.

[0009] Figure 2A This is a top view of an image sensor according to some embodiments of the present invention.

[0010] Figure 2B This is a magnified top view of an image sensor according to some embodiments of the present invention.

[0011] The reference numerals in the attached figures are explained as follows:

[0012] 10, 20, 30, 40, 50, 60: Image sensor

[0013] 100: Substrate

[0014] 102A: First photodiode

[0015] 102B: Second photodiode

[0016] 104: Intermediate Layer

[0017] 106A, 106B: Light guide structure

[0018] 108: Microlens layer

[0019] 108M: Microlens

[0020] 110: Color filter array

[0021] 110A, 110B, 110C: Colored filter layers

[0022] 112: Passivation layer

[0023] 114: Line Layer

[0024] 116: Minimum repeating unit

[0025] A-A': line segment

[0026] θ1, θ2: Angles Detailed Implementation

[0027] The image sensor of the present invention is described in detail below. For illustrative purposes, numerous specific details and embodiments are set forth in the following detailed description to provide a complete understanding of the embodiments of the present invention. The specific elements and configurations described in the following detailed description are intended to clearly illustrate the embodiments of the present invention. However, the exemplary embodiments described herein are obviously used for illustrative purposes only, and the concept of the embodiments of the present invention can be presented in various forms and is not limited to these exemplary embodiments.

[0028] Furthermore, to clearly describe the embodiments of the present invention, similar and / or corresponding numbers may be used in the drawings of different embodiments to represent similar and / or corresponding elements. However, this does not imply any relationship between the different embodiments. It should be understood that the description of this exemplary embodiment should be understood in conjunction with the drawings, and the drawings of the embodiments of the present invention are also considered part of the description of the embodiments of the present invention. The drawings are not drawn to scale with actual devices and elements. In addition, structures and devices are drawn schematically to simplify the drawings.

[0029] Furthermore, the phrase "a membrane layer is located above or on top of another membrane layer" can refer to a situation where the membrane layer is in direct contact with the other membrane layers. Alternatively, it could refer to a situation where the membrane layer is not in direct contact with the other membrane layers, in which case one or more intermediate layers are disposed between the membrane layer and the other membrane layers.

[0030] Furthermore, this specification uses relative terms. For example, "below," "bottom," "above," or "top" are used to describe the relative position of one element to another. It should be understood that if the device is flipped upside down, the element described as being on the "below" side will become the element on the "above" side.

[0031] It should be understood that although terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, films, and / or portions, these elements, components, regions, films, and / or portions should not be limited by these terms. These terms are only used to distinguish different elements, components, regions, films, and / or portions. Therefore, the first element, component, region, film, and / or portion discussed below may be referred to as the second element, component, region, film, and / or portion without departing from the teachings of embodiments of the present invention.

[0032] The terms “about” and “substantially” generally indicate that a given value or range is within 10%, preferably within 5%, or 3%, or 2%, or 1%, and more preferably within 0.5%. The given quantity is approximate; that is, even without specific mention of “about” or “substantially,” the meaning of “about” or “substantially” is implied.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should be understood that these terms, as defined in general dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant art and this invention, and should not be interpreted in an idealized or overly formal manner, unless specifically defined in the embodiments of this invention.

[0034] According to some embodiments of the present invention, a high dynamic range effect can be achieved by providing a light guide structure in the intermediate layer of an image sensor. Specifically, a light guide structure with high light transmittance can be disposed above a large photodiode to increase the sensitivity of the large photodiode, while a light guide structure with high attenuation rate can be disposed above a small photodiode to reduce the sensitivity of the small photodiode. Therefore, a larger sensitivity ratio between the large and small photodiodes can be achieved, thereby realizing better high dynamic range imaging.

[0035] Reference Figure 1A , Figure 1A This is a cross-sectional view of an image sensor 10 according to some embodiments of the present invention. The image sensor 10 includes a substrate 100, a first photodiode 102A, a second photodiode 102B, an intermediate layer 104, a light guide structure 106A, and a microlens layer 108. In some embodiments, for example, the substrate 100 may be a wafer or a chip, but the present invention is not limited thereto. In some embodiments, the substrate 100 may be a semiconductor substrate such as a silicon substrate. Furthermore, in some embodiments, the semiconductor substrate may also be an elemental semiconductor including germanium, a compound semiconductor, an alloy semiconductor, or a combination thereof. Compound semiconductors include gallium nitride (GaN), silicon carbide (SiC), gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), indium arsenide (InAs), and / or indium antimonide (InSb). Alloy semiconductors include silicon-germanium (SiGe) alloys, gallium arsenide phosphide (GaAsP) alloys, aluminum indium arsenide (AlInAs) alloys, aluminum gallium arsenide (AlGaAs) alloys, gallium indium arsenide (GaInAs) alloys, gallium indium phosphide (GaInP) alloys, and / or gallium arsenide phosphide (GaInAsP) alloys.

[0036] First photodiode 102A and second photodiode 102B are alternately disposed on substrate 100. The cross-sectional area of ​​first photodiode 102A is smaller than that of second photodiode 102B. Furthermore, in the top view (not shown) of image sensor 10, the area of ​​each first photodiode 102A is also smaller than the area of ​​each second photodiode 102B.

[0037] An intermediate layer 104 is disposed on the substrate 100. In some embodiments, the intermediate layer 104 may comprise an organic transparent material, a dielectric material, a semiconductor material such as silicon, any other suitable transparent material, or a combination thereof. More specifically, the material of the intermediate layer 104 may have a light transmittance greater than 90% for light with wavelengths between 200 nm and 1100 nm, or preferably greater than 95%. In some embodiments, the dielectric material includes silicon oxide, silicon nitride, silicon oxynitride, any other suitable dielectric material, or a combination thereof. The intermediate layer 104 may be formed using suitable deposition techniques such as spin-on coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), other suitable deposition processes, or combinations thereof.

[0038] In some embodiments, the extinction coefficient of the intermediate layer 104 may be between about 0.001 and about 0.01, for example, about 0.005. In some embodiments, the refractive index of the intermediate layer 104 may be between about 1.2 and about 1.8, for example, about 1.6.

[0039] A light guide structure is disposed in the intermediate layer 104 and above at least one first photodiode 102A or a second photodiode 102B. Specifically, in some embodiments, the light guide structure may be disposed only above at least one first photodiode 102A, or only above at least one second photodiode 102B. In other embodiments, the light guide structure may be disposed above at least one first photodiode 102A and at least one second photodiode 102B. That is, the light guide structure may be disposed simultaneously above one or more first photodiodes 102A and one or more second photodiodes 102B.

[0040] According to some embodiments of the present invention, such as Figure 1A As shown, the light guide structure 106A can be disposed in the intermediate layer 104 and on a portion of the first photodiode 102A, but the present invention is not limited thereto. It should be noted that other configurations of the light guide structure will be described and illustrated below and in subsequent figures.

[0041] In some embodiments, the light guide structure 106A may include organic materials such as acrylate polymers. For example, acrylate polymers can be made from methyl methacrylate, ethyl methacrylate, N-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, methyl acrylate, isopropyl acrylate, cyclohexyl methacrylate, 2-methyl cyclohexylmethacrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentenylmethacrylate, dicyclopentanyl methacrylate, dicyclopentanyloxyethyl methacrylate, isobornylmethacrylate, cyclohexyl acrylate, and 2-methylcyclohexyl acrylate. The light guide structure 106A may be formed from acrylate, dicyclopentanyloxyethylacrylate, isobornyl acrylate, phenylmethacrylate, phenyl acrylate, benzyl acrylate, 2-hydroxyethyl methacrylate, or combinations thereof. Furthermore, the light guide structure 106A may also include additional organic materials to adjust the extinction coefficient and refractive index of the light guide structure 106A to a desired range.In some embodiments, additional organic materials may include propylene glycol alkyl ether acetates, methoxy-containing organic esters, or combinations thereof. For example, propylene glycol alkyl ether acetates may include propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, and propylene glycol butyl ether acetate, or combinations thereof. For example, organic esters containing methoxy groups may include methyl methoxy acetate, ethyl methoxyacetate, propyl methoxy acetate, butyl methoxyacetate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, butyl 2-methoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, or combinations thereof.

[0042] In some embodiments, an opening (not shown) for the light guide structure 106A may be formed in the intermediate layer 104, and then the material of the light guide structure 106A may be deposited using any suitable process such as photolithography to form the light guide structure 106A. For example, the photolithography process may include coating, exposure, development, other suitable processes, or a combination thereof. Then, any suitable planarization process such as chemical mechanical polishing (CMP) may be used to remove excess material from the light guide structure 106A, making the intermediate layer 104 flush with the top surface of the light guide structure 106A.

[0043] Using organic materials in the light guide structure 106A is advantageous because the refractive index or extinction coefficient of the light guide structure 106A can be adjusted by changing the content of individual organic materials according to design requirements. Furthermore, using organic materials can also reduce the process complexity of forming the light guide structure 106A compared to conventional processes that use physical vapor deposition to form materials other than organic materials.

[0044] Furthermore, in some embodiments, the light guide structure 106A may have a rectangular or trapezoidal shape in cross-section. Moreover, in some embodiments, the angle θ1 between the sidewall and top surface of the light guide structure 106A may be between approximately 65 degrees and approximately 90 degrees, for example, approximately 75 degrees or approximately 80 degrees. When the light guide structure 106A has a fixed top surface area, the volume of the light guide structure 106A can be adjusted by changing the angle θ1, thereby adjusting the light attenuation efficiency of the light guide structure 106A according to design requirements to achieve the desired effect.

[0045] In some embodiments, the extinction coefficient of the light guide structure 106A may be between about 0.1 and about 0.3, for example, about 0.2. The refractive index of the light guide structure 106A is greater than the refractive index of the intermediate layer 104. In some embodiments, the refractive index of the light guide structure 106A may be between about 1.4 and about 2.0, for example, about 1.7. The light guide structure 106A with a higher refractive index allows incident light to enter the light guide structure 106A rather than the intermediate layer 104 near the light guide structure 106A. Furthermore, the light guide structure 106A with an extinction coefficient within the above range can reduce the sensitivity of the first photodiode 102A disposed below the light guide structure 106A, thereby increasing the sensitivity ratio of the second photodiode 102B to the first photodiode 102A and achieving a high dynamic range effect.

[0046] A microlens layer 108 is disposed on the intermediate layer 104. In some embodiments, the microlens layer 108 may include a plurality of microlenses 108M, and each microlens 108M may be disposed above a first photodiode 102A and a second photodiode 102B. In some embodiments, the material of the microlens layer 108 may be a transparent material. More specifically, the material of the microlens layer 108 may have a light transmittance greater than 90% for light with wavelengths between 200 nm and 1100 nm, or preferably greater than 95%. For example, the material of the microlens layer 108 may include epoxy resin, silicone resin, polyurethane, any other suitable material, or a combination thereof. The microlens layer 108 may be formed by depositing the material of the microlens layer 108 and then patterning the material of the microlens layer 108. The microlenses 108M of the microlens layer 108 may be formed into desired shapes, such as... Figure 1A The dome shape shown.

[0047] Refer again Figure 1A In some embodiments, the image sensor 10 may further include a color filter array 110 disposed between the intermediate layer 104 and the microlens layer 108. The color filter array 110 may have multiple color filter layers 110A, 110B, and 110C. For example... Figure 1A As shown, in some embodiments, color filter layers 110A, 110B, and 110C may each overlap with two adjacent microlenses 108M in the microlens layer 108. Furthermore, in some embodiments, color filter layers 110A, 110B, and 110C may each correspond to a first photodiode 102A located under one microlens 108M and a second photodiode 102B located under another adjacent microlens 108M. That is, in these embodiments, the configuration of color filter layers 110A, 110B, and 110C is offset from the configuration of the microlenses 108M, such that each color filter layer 110A, 110B, and 110C does not correspond to a first photodiode 102A and a second photodiode 102B under the same microlens 108M. Figure 1A In the embodiment shown, the bottom surface of the light guide structure 106A can contact the first photodiode 102A, and the top surface of the light guide structure 106A can also contact the color filter array 110.

[0048] In some embodiments, the color filter layers 110A, 110B, and 110C may have different colors from each other. For example, the colors of the color filter layers 110A, 110B, and 110C may be red, green, blue, or white. The color filter layer array 110 can be formed sequentially in different steps using coating, exposure, and development processes. Alternatively, the color filter layer array 110 can be formed using ink-jet printing.

[0049] Refer again Figure 1A The image sensor 10 may also include a passivation layer 112. The passivation layer 112 may be compliantly deposited on the microlens layer 108 to cover the entire surface of each individual microlens 108M. The material of the passivation layer 112 may be similar to or the same as the material of the microlens layer 108, and will not be described again here. However, in some embodiments, the refractive index of the passivation layer 112 may be less than the refractive index of the microlens layer 108, allowing incident light to enter the image sensor 10 in a progressive manner. The passivation layer 112 may also protect the microlens layer 108.

[0050] Refer again Figure 1A The image sensor 10 may also include a circuit layer 114 disposed in the intermediate layer 104. The circuit layer 114 may be a metal circuit for internally connecting the first photodiode 102A, the second photodiode 102B, the transistor (not shown), and the peripheral circuitry and external components of the device. In some embodiments, the material of the circuit layer 114 may include silver (Ag), aluminum (Al), gold (Au), copper (Cu), niobium (Nb), nickel (Ni), titanium (Ti), tungsten (W), silver alloys, aluminum alloys, gold alloys, copper alloys, niobium alloys, nickel alloys, titanium alloys, tungsten alloys, or combinations thereof.

[0051] As described above, according to embodiments of the present invention, the image sensor 10 may include a light guide structure 106A disposed in an intermediate layer 104 and disposed above at least one first photodiode 102A (i.e., a small photodiode). The refractive index of the light guide structure 106A is greater than that of the intermediate layer 104, and the light guide structure 106A may have a high light attenuation rate. Therefore, the sensitivity of a portion of the first photodiode 102A (i.e., the small photodiode) can be reduced, and the sensitivity ratio of the second photodiode 102B (i.e., the large photodiode) to the first photodiode can be increased. High dynamic range imaging can be achieved using the image sensor 10 provided by the embodiments of the present invention.

[0052] Next, refer to Figure 1B , Figure 1B This is a cross-sectional view of an image sensor 20 according to another embodiment of the present invention. Figure 1B Image sensor 20 and Figure 1ASimilar to the image sensor 10, but the light guide structure 106A is disposed above all the first photodiodes 102A. In this way, the sensitivity ratio of the second photodiode 102B to the first photodiode 102A can be further increased to achieve a better high dynamic range effect.

[0053] Next, refer to Figure 1C , Figure 1C This is a cross-sectional view of an image sensor 30 according to another embodiment of the present invention. Figure 1C Image sensor 30 and Figure 1A The image sensor 30 is similar to the image sensor 10, but the image sensor 30 includes a light guide structure 106B instead of a light guide structure 106A. According to some embodiments of the present invention, such as... Figure 1C As shown, the light guide structure 106B can be disposed in the intermediate layer 104 and above a portion of the second photodiode 102B (i.e., the large photodiode). Furthermore, in some embodiments, the extinction coefficient of the light guide structure 106B can be less than that of the light guide structure 106A, thus the light guide structure 106B can have better light transmission efficiency.

[0054] In some embodiments, the light guide structure 106B may comprise an organic material such as a resin polymer. For example, the resin polymer may comprise epoxy resin; acrylate polymers such as polymethyl methacrylate (PMMA); various resins such as polydimethylsiloxane (PDMS), polyurethane, polycarbonate (PC), polyester, polyketone, polyimide (PI), polyvinyl alcohol, fluororesin, and polyolefin; or combinations thereof. In some specific embodiments, the light guide structure 106B may be formed from polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polycarbonate (PC), or combinations thereof. The method of forming the light guide structure 106B is similar to or the same as the method of forming the light guide structure 106A, and will not be repeated here.

[0055] Using organic materials for the light guide structure 106B is advantageous because the refractive index or extinction coefficient of the light guide structure 106B can be adjusted by changing the composition of the organic materials according to design requirements. Furthermore, as mentioned above, using organic materials can also reduce the process complexity of forming the light guide structure 106B compared to conventional processes that utilize physical vapor deposition to form materials other than organic materials.

[0056] Furthermore, in some embodiments, the light guide structure 106B may have a rectangular or trapezoidal shape in cross-section. Moreover, in some embodiments, the angle θ2 between the sidewall and top surface of the light guide structure 106B may be between approximately 65 degrees and approximately 90 degrees, for example, approximately 75 degrees or approximately 80 degrees. When the light guide structure 106B has a fixed top surface area, the volume of the light guide structure 106B can be adjusted by changing the angle θ2, thereby adjusting the light transmission efficiency of the light guide structure 106B according to design requirements to achieve the desired effect.

[0057] In some embodiments, the extinction coefficient of the light guide structure 106B may be between about 0.001 and about 0.01, for example, about 0.005. The refractive index of the light guide structure 106B is greater than the refractive index of the intermediate layer 104. In some embodiments, the refractive index of the light guide structure 106B may be between about 1.4 and about 2.0, for example, about 1.7. The light guide structure 106B with a higher refractive index allows incident light to enter the light guide structure 106B rather than the intermediate layer 104 near the light guide structure 106B. Furthermore, the light guide structure 106B with an extinction coefficient within the above range can increase the sensitivity of the second photodiode 102B disposed below the light guide structure 106B, thereby increasing the sensitivity ratio of the second photodiode 102B to the first photodiode 102A and achieving the desired high dynamic range effect.

[0058] Next, refer to Figure 1D , Figure 1D This is a cross-sectional view of an image sensor 40 according to another embodiment of the present invention. Figure 1D Image sensor 40 and Figure 1C Similar to the image sensor 30, but the light guide structure 106B is disposed on all the second photodiodes 102B. In this way, the sensitivity ratio of the second photodiodes 102B to the first photodiodes 102A can be further increased to achieve a better high dynamic range effect.

[0059] Next, refer to Figure 1E , Figure 1E This is a cross-sectional view of an image sensor 50 according to another embodiment of the present invention. Figure 1E Image sensor 50 and Figure 1A Similar to the image sensor 10, but the image sensor 50 also includes a light guide structure 106B. The light guide structure 106B can be disposed in the intermediate layer 104 and above a portion of the second photodiode 102B. It should be noted that... Figure 1EIn the illustrated embodiment, light guide structures 106A and 106B can be respectively disposed above a portion of the first photodiode 102A and a portion of the second photodiode 102B below the same color filter layer. That is, light guide structures 106A and 106B can be disposed below a portion of the color filter layer, rather than all of it. For example, as... Figure 1E As shown, light guide structures 106A and 106B can be disposed on the first photodiode 102A and the second photodiode 102B below the color filter layer 110A and / or 110C, while light guide structures 106A and 106B can be disposed outside the first photodiode 102A and the second photodiode 102B below the color filter layer 110B.

[0060] By simultaneously providing light guide structures 106A and 106B on portions of the first photodiode 102A and the second photodiode 102B, the sensitivity of the first photodiode 102A can be reduced while the sensitivity of the second photodiode 102B can be increased. Therefore, the sensitivity ratio of the second photodiode 102B to the first photodiode 102A can be increased to achieve a better high dynamic range effect.

[0061] Next, refer to Figure 1F , Figure 1F This is a cross-sectional view of an image sensor 60 according to another embodiment of the present invention. Figure 1F Image sensor 60 and Figure 1E Similar to the image sensor 50, but light guide structures 106A and 106B are disposed above all the first photodiodes 102A and second photodiodes 102B. Simultaneously, light guide structures 106A and 106B can be disposed below all the color filter layers 110A, 110B, and 110C. In this way, the sensitivity ratio of the second photodiode 102B to the first photodiode 102A can be further increased, thereby providing better high dynamic range performance.

[0062] Reference Figure 2A and Figure 2B , Figure 2A This is a top view of an image sensor 10 according to some embodiments of the present invention, and Figure 2B This is an enlarged top view of an image sensor 10 according to some embodiments of the present invention. It should be noted that... Figure 1A The cross-sectional view is along Figure 2A The line segment A-A' is captured. Furthermore, Figure 2A and Figure 2B For the sake of simplicity, the passivation layer 112 has been omitted.

[0063] In some embodiments, such as Figure 2AAs shown, the image sensor 10 can be formed from a minimum repeating unit 116. The minimum repeating unit 116 can be a sensor array defined by four microlenses 108M and arranged in a 2x2 pattern. A magnified schematic diagram of the minimum repeating unit 116 is illustrated in... Figure 2B In some embodiments, the color filter layers 110A, 110B, and 110C may have a rectangular shape, a square shape, or a combination thereof. Figure 2B As shown, in the minimum repeating unit 116, color filter layer 110A has a square shape, color filter layer 110B has a rectangular or square shape, and color filter layer 110C has a rectangular shape, but the invention is not limited thereto. In embodiments where the minimum repeating unit 116 is defined by other microlenses 108M and arranged in a 2x2 pattern, color filter layer 110A may also have a rectangular shape and color filter layer 110C may also have a square shape.

[0064] As previously stated, Figure 2B In this configuration, color filter layers 110A, 110B, and 110C can each overlap with two adjacent microlenses 108M. Furthermore, any two adjacent color filter layers 110A, 110B, and 110C can have different colors.

[0065] In summary, according to some embodiments of the present invention, an image sensor may have a light guide structure disposed on at least one first photodiode (i.e., a small photodiode) or a second photodiode (i.e., a large photodiode). More specifically, a light guide structure with high light transmittance may be disposed in an intermediate layer and above the large photodiode to increase the sensitivity of the large photodiode, and a light guide structure with high light attenuation rate may be disposed in an intermediate layer and above the small photodiode to reduce the sensitivity of the small photodiode. Therefore, a large sensitivity ratio between the large and small photodiodes can be achieved, and an image sensor with a high sensitivity ratio can realize high dynamic range imaging.

[0066] While some embodiments and advantages of the present invention have been described in detail, it should be understood that various modifications, substitutions, and refinements can be made without departing from the spirit and scope of the invention as defined by its protection scope. For example, those skilled in the art to which this invention pertains will readily understand that many components, functions, processes, and materials described herein can be altered without departing from the scope of the invention. Furthermore, the scope of this application is not limited to the specific embodiments of processes, machines, manufacturing, material composition, methods, and steps described in the specification. Those skilled in the art to which this invention pertains will readily understand from the present invention that any existing or future processes, machines, manufacturing, material composition, methods, or steps that can achieve substantially the same function or substantially the same result as the corresponding embodiments described herein can be used according to the embodiments of the present invention. Therefore, the protection scope of the present invention includes the aforementioned processes, machines, manufacturing, material composition, methods, or steps.

Claims

1. An image sensor, comprising: A single substrate has multiple image segments; A plurality of first photodiodes and a plurality of second photodiodes are alternately disposed in the substrate, wherein one of the first photodiodes and one of the second photodiodes are provided in each of the image segments, wherein the area of ​​each first photodiode in the top view is smaller than the area of ​​each second photodiode; An intermediate layer is disposed on the substrate; A light guide structure is disposed in the intermediate layer and on at least one of the first photodiode or the second photodiode, wherein the refractive index of the light guide structure is greater than the refractive index of the intermediate layer; A microlens layer is disposed on the intermediate layer; and A color filter array having multiple color filter layers disposed between the intermediate layer and the microlens layer, wherein each color filter layer overlaps only with the first photodiode in the first image segment and the second photodiode in the second image segment, wherein the second image segment is adjacent to the first image segment.

2. The image sensor as claimed in claim 1, wherein, The angle between one side wall and one top surface of the light guide structure is between 65 and 90 degrees, and the light guide structure has a rectangular or trapezoidal shape in cross-section.

3. The image sensor as claimed in claim 1, wherein, The light guide structure is disposed on at least one of the first photodiodes; The extinction coefficient of this light guide structure is between 0.1 and 0.3; and The refractive index of the light guide structure is between 1.4 and 2.

0.

4. The image sensor as claimed in claim 1, wherein, The light guide structure is disposed on at least one of the second photodiodes; The extinction coefficient of this light guide structure is between 0.001 and 0.01; and The refractive index of the light guide structure is between 1.4 and 2.

0.

5. The image sensor as claimed in claim 1, wherein, The light guide structure is disposed on at least one of the first photodiodes and on at least one of the second photodiodes; The refractive index of this light guide structure is between 1.4 and 2.0; The light guide structure disposed on at least one of the first photodiodes has an extinction coefficient between 0.1 and 0.3; and The light guide structure disposed on at least one of the second photodiodes has an extinction coefficient between 0.001 and 0.

01.

6. The image sensor as claimed in claim 1, wherein, This microlens layer includes multiple microlenses; Each of the microlenses is disposed on one of the first photodiodes and one of the second photodiodes; and Each of the colored filter layers overlaps with two adjacent microlenses.

7. The image sensor as claimed in claim 6, wherein, Each of the color filter layers corresponds to one of the first photodiodes located under one of the microlenses, and each of the second photodiodes corresponds to one of the second photodiodes located under the other of the microlenses, wherein the other of the microlenses is adjacent to the first of the microlenses. Any two adjacent colored filter layers have different colors; and The color filter layer has a rectangular shape, a square shape, or a combination thereof in the top view.

8. The image sensor of claim 1 further includes a passivation layer disposed on the microlens layer.

9. An image sensor, comprising: A single substrate has multiple image segments; A plurality of first photodiodes and a plurality of second photodiodes are alternately disposed in the substrate, wherein one of the first photodiodes and one of the second photodiodes are provided in each of the image segments, wherein the area of ​​each first photodiode in the top view is smaller than the area of ​​each second photodiode; An intermediate layer is disposed on the substrate; A light-guiding structure is disposed in the intermediate layer and on at least one of the first photodiode or the second photodiode; A color filter array having multiple color filter layers disposed on the intermediate layer; and A microlens layer is disposed on the color filter array, wherein the microlens layer includes a plurality of microlenses, and wherein each color filter layer overlaps with two adjacent microlenses, wherein each color filter layer overlaps only with the first photodiode in the first image segment and the second photodiode in the second image segment, wherein the second image segment is adjacent to the first image segment.

10. The image sensor of claim 9, wherein, The refractive index of the light guide structure is greater than that of the intermediate layer; Each of the microlenses is disposed on one of the first photodiodes and on one of the second photodiodes; Each of the color filter layers corresponds to one of the first photodiodes located under one of the microlenses, and each corresponds to one of the second photodiodes located under the other of the microlenses, wherein the other microlens is adjacent to the first of the microlenses; and Any two adjacent colored filter layers have different colors.

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