Image sensor

Abstract

An image sensor according to one embodiment comprises a sensor substrate including a photoelectric conversion region, a spacer layer located on the sensor substrate, and a chromatic separation lens layer located on the spacer layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer and a second refractive layer, wherein the second refractive layer is located along the bottom surface and side surface of the first refractive layer, and the refractive index of the first refractive layer is greater than the refractive index of the second refractive layer.

Description

Technology Field

[0001] The present invention relates to an image sensor. Background Technology

[0002] An image sensor is a semiconductor device that converts an optical image into an electrical signal. Image sensors can be classified into CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) types, and CMOS type image sensors are abbreviated as CIS (CMOS Image Sensor). A CIS is equipped with multiple pixels arranged in two dimensions, and each pixel includes a photodiode (PD). The photodiode plays the role of converting incident light into an electrical signal.

[0003] Recently, attempts have been made to use chromatic separation lens layers instead of color filters to improve the light utilization efficiency of image sensors. Chromatic separation lens layers separate the colors of incident light by utilizing the diffraction or refraction characteristics of light that differ depending on wavelength, and can control wavelength-specific directionality based on their refractive index and shape. The colors separated by the chromatic separation lens layers can be delivered to their respective corresponding pixels. The problem to be solved

[0004] The present invention provides an image sensor comprising fine nanoposts and a method for manufacturing the same. means of solving the problem

[0005] An image sensor according to one embodiment comprises a sensor substrate including a photoelectric conversion region, a spacer layer located on the sensor substrate, and a chromatic separation lens layer located on the spacer layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer and a second refractive layer, wherein the second refractive layer is located along the bottom surface and side surface of the first refractive layer, and the refractive index of the first refractive layer is greater than the refractive index of the second refractive layer.

[0006] An image sensor according to another embodiment comprises a sensor substrate including a photoelectric conversion region, a spacer layer located on the sensor substrate, an intermediate layer located on the spacer layer, and a chromatic separation lens layer located on the intermediate layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer and a second refractive layer, wherein the second refractive layer is located along the bottom surface and side surface of the first refractive layer, and the refractive index of the first refractive layer is greater than the refractive index of the second refractive layer and the dielectric layer.

[0007] An image sensor according to another embodiment comprises a sensor substrate including a photoelectric conversion region, a spacer layer located on the sensor substrate, and a chromatic separation lens layer located on the spacer layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer, and the dielectric layer is located on the bottom surface and side surface of the first refractive layer, and the bottom surface of the dielectric layer is located closer to the spacer layer than the bottom surface of the first refractive layer.

[0008] A method for manufacturing an image sensor according to one embodiment includes the steps of patterning a dielectric layer to form an opening, forming a second material layer on the opening and the dielectric layer, and forming a first material layer on the second material layer, wherein the refractive index of the first material layer may be greater than the refractive index of the second material layer.

[0009] The step of forming the second material layer can be performed by an ALD process.

[0010] The thickness of the second material layer may be 5 nm to 30 nm.

[0011] The refractive index of the second material layer may be greater than the refractive index of the dielectric layer.

[0012] The second material layer may include the same material as the dielectric layer.

[0013] The method further includes the step of forming nanoposts by performing a CMP process on the second material layer and the first material layer, wherein the width of the first material layer included in the nanoposts may be smaller than the width of the opening formed in the step of patterning the dielectric layer to form an opening.

[0014] The width of the first material layer may be 50 nm to 250 nm.

[0015] The second material layer may be located along the bottom surface and side of the first material layer.

[0016] The dielectric layer above may include SiO2, and the first material layer may include TiO2. Effects of the invention

[0017] According to the embodiments, an image sensor comprising fine nanoposts and a method for manufacturing the same are provided. Brief explanation of the drawing

[0018] FIG. 1 is an example block diagram of an image sensor according to one embodiment. Figure 2 is a conceptual diagram schematically showing the pixel array structure of the image sensor of Figure 1. Figure 3 is a cross-sectional view taken along line II' of Figure 2. FIG. 4 illustrates the same area as FIG. 3 for another embodiment. FIG. 5 illustrates the same area as FIG. 3 for another embodiment. FIG. 6 illustrates the same area as FIG. 3 for another embodiment. FIG. 7 illustrates the same area as FIG. 4 for another embodiment. Figure 8 illustrates the same area as Figure 5 for another embodiment. FIG. 9 illustrates the same area as FIG. 3 for another embodiment. FIG. 10 illustrates the same area as FIG. 9 for another embodiment. FIG. 11 illustrates the same area as FIG. 10 for another embodiment. FIG. 12 is a cross-sectional view briefly illustrating the structure of an image sensor. Figure 13 shows a portion of the cross-section of the sensor substrate. FIGS. 14 and 15 are plan views showing an array of pixels and an array of light-sensing cells corresponding to pixel areas in an image sensor according to the present embodiment. FIG. 16 is a plan view showing the arrangement of nano posts in the chromatic separation lens layer of an image sensor according to the present embodiment. Figure 17 is an enlarged plan view showing an enlarged portion of Figure 16. FIGS. 18 to 21 are cross-sectional views schematically illustrating the process of an image sensor manufacturing method according to an embodiment of the present invention. FIG. 22 is a block diagram of an electronic device including an image sensor according to one embodiment of the present invention. Specific details for implementing the invention

[0019] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0020] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0021] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0022] Furthermore, when a part such as a layer, membrane, region, or plate is said to be "on" or "on" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Also, being "on" or "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "on" in the direction opposite to gravity.

[0023] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0024] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0025] FIG. 1 is an example block diagram of an image sensor according to one embodiment.

[0026] Referring to FIG. 1, an image sensor (1000) according to one embodiment may include a controller (1110), a timing generator (1120), a row driver (1130), a pixel array (1140), a readout circuit (1150), a ramp signal generator (1160), a data buffer (1170), and an image signal processor (1180). In one embodiment, the image signal processor (1180) may be located outside the image sensor (1000).

[0027] The image sensor (1000) can generate an image signal by converting light received from the outside into an electrical signal. The image signal (IMS) can be provided to an image signal processor (1180).

[0028] The image sensor (1000) may be mounted on an electronic device having an image or light sensing function. For example, the image sensor (1000) may be mounted on an electronic device such as a camera, smartphone, wearable device, Internet of Things (IoT) device, home appliance, tablet PC (Personal Computer), PDA (Personal Digital Assistant), PMP (portable multimedia player), navigation, drone, advanced drivers assistance system (ADAS), etc. Alternatively, the image sensor (1000) may be mounted on an electronic device equipped as a component in a vehicle, furniture, manufacturing equipment, door, various measuring instruments, etc.

[0029] The controller (1110) can control each component (1120, 1130, 1150, 1160, 1170) included in the image sensor (1000) overall. The controller (1110) may also control the operation timing of each component (1120, 1130, 1150, 1160, 1170) using control signals. In one embodiment, the controller (1110) receives a mode signal indicating an imaging mode from an application processor and can control the image sensor (1000) overall based on the received mode signal. For example, the application processor may determine the imaging mode of the image sensor (1000) according to various scenarios such as the illumination of the imaging environment, the user's resolution settings, and a sensed or learned state, and provide the determined result to the controller (1110) as a mode signal. The controller (1110) can control a plurality of pixels of the pixel array (1140) to output pixel signals according to the imaging mode, and the pixel array (1140) can output a pixel signal for each of the plurality of pixels or a pixel signal for some of the plurality of pixels, and the readout circuit (1150) can sample and process the pixel signals received from the pixel array (1140). The timing generator (1120) can generate a signal that serves as a reference for the operation timing of the components of the image sensor (1000). The timing generator (1120) can control the timing of the row driver (1130), the readout circuit (1150), and the ramp signal generator (1160). The timing generator (1120) can provide a control signal that controls the timing of the row driver (1130), the readout circuit (1150), and the ramp signal generator (1160).

[0030] A pixel array (1140) may include a plurality of pixels (PX), and a plurality of row lines (RL) and a plurality of column lines (DL) each connected to a plurality of pixels (PX). In one embodiment, each pixel (PX) may include at least one photoelectric conversion element. The photoelectric conversion element detects incident light and converts the incident light into an electrical signal according to the amount of light, i.e., a plurality of analog pixel signals. The photoelectric conversion element may be a photodiode, a pind diode, etc. Additionally, the photoelectric conversion element may be a SPAD (Single-Photon Avalanche Diode) applied to a 3D sensor pixel. The level of the analog pixel signal output from the photoelectric conversion element may be proportional to the amount of charge output from the photoelectric conversion element. That is, the level of the analog pixel signal output from the photoelectric conversion element may be determined according to the amount of light received into the pixel array (1140).

[0031] Multiple row lines (RL) extend in a first direction and can be connected to pixels (PX) arranged along the first direction. For example, a control signal output from a row driver (1130) to a row line (RL) can be transmitted to the gate of a transistor of a plurality of pixels (PX) connected to the row line (RL). A column line (DL) extends in a second direction intersecting the first direction and can be connected to pixels (PX) arranged along the second direction. Multiple pixel signals output from multiple pixels (PX) can be transmitted to a readout circuit (1150) through multiple column lines (DL).

[0032] The row driver (1130) generates a control signal to drive the pixel array (1140) in response to a control signal from the timing generator (1120) and can provide the control signal to a plurality of pixels (PX) of the pixel array (1140) through a plurality of row lines (RL). In one embodiment, the row driver (1130) can control the pixels (PX) to detect incident light in units of row lines. A row line unit may include at least one row line (RL).

[0033] The readout circuit (1150) can convert a pixel signal (or electrical signal) from pixels (PX) connected to a selected row line (RL) among a plurality of pixels (PX) into a pixel value representing the amount of light in response to a control signal from the timing generator (1120). The readout circuit (1150) can convert a pixel signal output through a corresponding column line (DL) into a pixel value. For example, the readout circuit (1150) can convert a pixel signal into a pixel value by comparing a lamp signal and a pixel signal. The pixel value may be image data having a plurality of bits. Specifically, the readout circuit (1150) may include a selector, a plurality of comparators, and a plurality of counter circuits, etc.

[0034] The lamp signal generator (1160) can generate a reference signal and transmit it to the readout circuit (1150).

[0035] The ramp signal generator (1160) may include a current source, a resistor, and a capacitor. The ramp signal generator (1160) can generate a plurality of ramp signals that fall or rise with a slope determined by the current magnitude of the variable current source or the resistance value of the variable resistor by adjusting the ramp voltage, which is the voltage applied to the ramp resistor, by adjusting the current magnitude of the variable current source or the resistance value of the variable resistor.

[0036] The data buffer (1170) stores pixel values ​​of a plurality of pixels (PX) connected to a selected column line (DL) transmitted from the readout circuit (1150), and can output the stored pixel values ​​in response to an enable signal from the controller (1110).

[0037] The image signal processor (1180) can perform image signal processing on an image signal received from the data buffer (1170). For example, the image signal processor (1180) can receive multiple image signals from the data buffer (1170) and synthesize the received image signals to generate a single image.

[0038] In one embodiment, a plurality of pixels may be grouped in an M*N form (where M and N are integers greater than or equal to 2) to form a unit pixel group. The M*N form may be a form in which M pixels are arranged in the column line (DL) arrangement direction and N pixels are arranged in the row line (RL) arrangement direction. For example, a unit pixel group may include a plurality of pixels arranged in a 2*2 form, and a unit pixel group may output a single analog pixel signal. The following embodiment is not limited to a single pixel and may also be applied to a unit pixel group.

[0039] FIG. 2 is a conceptual diagram schematically showing the pixel array structure of the image sensor of FIG. 1. FIG. 3 is a cross-sectional view taken along line II' of FIG. 2.

[0040] Referring to FIGS. 2 and 3, the pixel array may include a sensor substrate (100), a chromatic separation lens layer (200), and a spacer layer (300). The sensor substrate (100) may include a plurality of light-sensing cells that sense light. The specific arrangement of the light-sensing cells will be described later with reference to FIG. 15. In the image sensor of the present embodiment, the light-sensing cell may be, for example, a photodiode (PD). However, the light-sensing cell is not limited to a photodiode. The chromatic separation lens layer (200) is located on the spacer layer (300) and may include a plurality of nanoposts (NP).

[0041] Although not illustrated in FIGS. 2 and 3, the image sensor according to the present embodiment may further include a color filter located between the sensor substrate (100) and the spacer layer (300). However, depending on the embodiment, the color filter may be omitted. A specific structure will be described in detail later with reference to FIG. 12.

[0042] The chromatic separation lens layer (200) can divert incident light to cause light of different wavelength spectra to be incident on at least two different light-sensing cells of the sensor substrate (100). To this end, the size, position, and arrangement of nano posts (NP) in the chromatic separation lens layer (200) can be appropriately set. The chromatic separation lens layer (200) may have a plurality of regions facing each of the plurality of light-sensing cells of the sensor substrate (100). In addition, depending on the arrangement relationship between each region and the plurality of nano posts (NP), the incident light may have a predetermined phase distribution immediately after passing through the chromatic separation lens layer (200).

[0043] The color separation lens layer (200) may include nano posts (NP) and a dielectric layer (205). The nano posts (NP) may have a cylindrical shape as shown in FIGS. 2 and 3. However, the shape of the nano posts (NP) is not limited to a cylindrical shape. The nano posts (NP) may have various sizes and may be spaced apart from each other on the upper surface of the spacer layer (300). The dielectric layer (205) may fill the spaces between the nano posts (NP). The dielectric layer (205) may include a material having a lower refractive index than the material of the nano posts (NP). For example, the dielectric layer (205) may include SiO2. However, the material of the dielectric layer (205) is not limited to SiO2.

[0044] The nano post (NP) may include a first refractive layer (201) and a second refractive layer (203). The first refractive layer (201) constitutes the central body of the nano post (NP) and may have a cylindrical shape corresponding to the shape of the nano post (NP). However, if the shape of the nano post (NP) is not cylindrical, the shape of the first refractive layer (201) may also not be cylindrical.

[0045] As illustrated in FIG. 3, the second refractive layer (203) may have a shape that surrounds the bottom surface and side of the first refractive layer (201). As will be explained separately later, the second refractive layer (203) and the dielectric layer (205) may contain the same material. In this case, the boundary between the second refractive layer (203) and the dielectric layer (205) may not be distinguished and may be perceived as one. That is, when the second refractive layer (203) and the dielectric layer (205) contain the same material, the nano post (NP) may be perceived as containing the second refractive layer (203), and the bottom surface and side of the first refractive layer (201) may have a shape that is surrounded by the dielectric layer (205). This will be explained in detail separately in FIG. 6 to FIG. 8 later.

[0046] The first refractive layer (201) and the second refractive layer (203) can be formed of a material having a higher refractive index than the material of the dielectric layer (205). Generally, a high refractive index can be defined based on SiO2. That is, the first refractive layer (201) and the second refractive layer (203) can have a higher refractive index than SiO2.

[0047] For example, the first refractive layer (201) may include any one of SiN3, Si3N4, ZnS, GaN, ZnSe, TiO2, and hydrogen-doped amorphous silicon (a-Si:H).

[0048] Additionally, the second refractive layer (203) may include a material with a lower refractive index than the first refractive layer (201). In this case, the refractive index of the second refractive layer (203) may be equal to or higher than the refractive index of the dielectric layer (205) and lower than that of the first refractive layer (201). That is, the refractive indices may be higher in the order of dielectric layer (205), second refractive layer (203), and first refractive layer (201). For example, the second refractive layer (203) may include SiO2 or Al2O3. However, these materials are examples, and the present invention is not limited thereto.

[0049] The thickness (D1) of the second refractive layer (203) may be 5 nm to 30 nm. Additionally, the width (D2) of the first refractive layer (201) may be 50 nm to 250 nm. In this specification, the width (D2) of the first refractive layer (201) refers to the width of the widest part in a plane. That is, if the first refractive layer (201) is cylindrical in shape, the width (D2) of the first refractive layer (201) is the diameter.

[0050] As will be explained separately later, the second refractive layer (203) can be formed by an ALD (Atomic Layer Deposition) process. By forming the second refractive layer (203) in this way, a first refractive layer (201) having a fine width can be formed.

[0051] In order to form nano posts (NPs), a dielectric layer (205) is first formed, and nano posts (NPs) can be formed through patterning. At this time, as the resolution of the image sensor increases, the size of a single pixel becomes smaller, and accordingly, the size of individual nano posts (NPs) also needs to be formed small. However, the process of forming such fine patterns is not easy. Since the formation of nano posts (NPs) is performed after the formation of the sensor substrate (100), there is a limitation that a high-temperature process cannot be used during the nano post (NP) formation process. This is because using a high-temperature process can cause damage to the already formed sensor substrate (100). Specifically, a high-temperature process of 250°C or higher cannot be used, and therefore there is a limitation when selecting a hard mask to form fine patterns. However, in the case of the present embodiment, after forming and patterning the dielectric layer (205), a second refractive layer (203) is formed by an ALD (Atomic Layer Deposition) process. Accordingly, the width of the formed micro-pattern is reduced by the thickness of the second refractive layer (203), and a first refractive layer (201) having a fine width can be formed. Specific effects will be explained in detail later in the manufacturing method of FIGS. 18 to 21.

[0052] The spacer layer (300) is placed between the sensor substrate (100) and the chromatic separation lens layer (200) and serves to maintain a constant gap between the sensor substrate (100) and the chromatic separation lens layer (200). The spacer layer (300) may be made of a dielectric material that is transparent to visible light, such as SiO2 or silanolic glass (SOG; siloxane-based spin-on glass), which has a lower refractive index than nanoposts (NP) and has a low absorption rate in the visible light band. The thickness of the spacer layer (300) may be determined based on the focal length of the light collected by the chromatic separation lens layer (200), and may be selected, for example, within about 1 / 2 to about 1.5 times the focal length of the reference wavelength (λ0) light.

[0053] Referring to FIG. 3, an intermediate layer (500) may be located between the spacer layer (300) and the color separation lens layer (200). The intermediate layer (500) may function as an etching stop layer. Thus, as shown in FIG. 3, nano posts (NP) may be formed on the intermediate layer (500). The intermediate layer (500) may include Al2O3, but is not limited thereto.

[0054] In another embodiment, a portion of the intermediate layer (500) may be etched so that a portion of the nano post (NP) is located within the intermediate layer (500). Additionally, in another embodiment, the nano post (NP) may penetrate the intermediate layer (500) so that the bottom surface of the nano post (NP) is located below the bottom surface of the intermediate layer (500).

[0055] FIG. 4 illustrates the same area as FIG. 3 for another embodiment. With reference to FIG. 4, the image sensor according to this embodiment is identical to the embodiment of FIG. 3 except that the bottom surface of the nano post (NP) is located within the intermediate layer (500). A detailed description of the identical components is omitted. A structure like FIG. 4 can be formed by patterning a part of the intermediate layer (500) together with the dielectric layer (205) when patterning the dielectric layer (205). That is, in the embodiment of FIG. 4, the nano post (NP) can be located within a recess where the intermediate layer (500) is partially etched. As shown in FIG. 4, the bottom surface of the second refractive layer (203) is located within the intermediate layer (500), and a part of the side of the second refractive layer (203) can be in direct contact with the intermediate layer (500).

[0056] FIG. 5 illustrates the same area as FIG. 3 for another embodiment. With reference to FIG. 5, the image sensor according to this embodiment is identical to the embodiment of FIG. 3 except that the nano post (NP) penetrates the intermediate layer (500) and the bottom surface of the nano post (NP) is located lower than the bottom surface of the intermediate layer (500). A detailed description of the identical components is omitted. In the embodiment of FIG. 5, the bottom surface of the nano post (NP) may be located within the spacer layer (300). A structure such as FIG. 5 can be formed by patterning a portion of the intermediate layer (500) and the spacer layer (300) together when patterning the dielectric layer (205). That is, as shown in FIG. 5, the nano post (NP) is located penetrating the intermediate layer (500), and the bottom surface of the second refractive layer (203) may be located within the spacer layer (300).

[0057] Although the second refractive layer (203) and the dielectric layer (205) are shown separately in FIGS. 3 to 5, the second refractive layer (203) and the dielectric layer (205) may contain the same material. In this case, the boundary between the second refractive layer (203) and the dielectric layer (205) is not visible, and they may be seen as a single dielectric layer (205). FIG. 6 shows the same area as FIG. 3 in an embodiment where the second refractive layer (203) and the dielectric layer (205) contain the same material. Referring to FIG. 6, the image sensor according to the present embodiment is identical to FIG. 3 except that the dielectric layer (205) is located in the area where the second refractive layer (203) was located. A detailed description of the identical components is omitted. Referring to FIG. 6, the bottom surface and side surface of the first refractive layer (201) may be surrounded by the dielectric layer (205). Accordingly, as shown in FIG. 6, the thickness (H2) of the thickest part of the dielectric layer (205) may be greater than the thickness (H1) of the first refractive layer (201). Likewise, as shown in FIG. 6, the bottom surface of the dielectric layer (205) may be located below the bottom surface of the first refractive layer (201). As shown in FIG. 6, the thickness (D4) of the dielectric layer (205) located on the bottom surface of the first refractive layer (201) may be 5 nm to 30 nm.

[0058] FIG. 7 illustrates the same region as FIG. 4 in an embodiment in which the second refractive layer (203) and the dielectric layer (205) include the same material. Referring to FIG. 7, the image sensor according to the present embodiment is identical to FIG. 4 except that the dielectric layer (205) is located in the region where the second refractive layer (203) was located. A detailed description of the identical components is omitted. Referring to FIG. 7, a portion of the dielectric layer (205) may be located within the intermediate layer (500).

[0059] FIG. 8 illustrates the same region as FIG. 5 in an embodiment in which the second refractive layer (203) and the dielectric layer (205) comprise the same material. Referring to FIG. 8, the image sensor according to the present embodiment is identical to FIG. 5 except that the dielectric layer (205) is located in the region where the second refractive layer (203) was located. A detailed description of the identical components is omitted. Referring to FIG. 8, a portion of the dielectric layer (205) may be located within the spacer layer (300).

[0060] Although FIGS. 3 to 8 show a configuration in which the color separation lens layer (200) is a single layer, in other embodiments, the color separation lens layer (200) may have a multi-layer stacked structure.

[0061] FIG. 9 illustrates the same region as FIG. 3 for another embodiment. Referring to FIG. 9, the chromatic separation lens layer (200) may include a first chromatic separation lens layer (200A) and a second chromatic separation lens layer (200B). The specific stacking structure of the first chromatic separation lens layer (200A) and the second chromatic separation lens layer (200B) is the same as that of the chromatic separation lens layer (200) described above, so a specific description of the same components is omitted. The arrangement of nano posts (NP) of the first chromatic separation lens layer (200A) and the arrangement of nano posts (NP) of the second chromatic separation lens layer (200B) may be the same or different from each other. As shown in FIG. 9, some of the nano posts (NP) located in the first chromatic separation lens layer (200A) may overlap with the nano posts (NP) located in the second chromatic separation lens layer (200B). However, in another embodiment, the nano post (NP) located in the first color separation lens layer (200A) may not overlap with the nano post (NP) located in the second color separation lens layer (200B).

[0062] In FIG. 9, a nano post (NP) located in the first chromatic separation lens layer (200A) comprises a first refractive layer (201) and a second refractive layer (203), and the refractive index of the first refractive layer (201) may be greater than the refractive index of the second refractive layer (203). Additionally, a nano post (NP) located in the second chromatic separation lens layer (200B) comprises a first refractive layer (201) and a second refractive layer (203), and the refractive index of the first refractive layer (201) may be greater than the refractive index of the second refractive layer (203). However, this is merely an example, and the refractive indices of the nano post (NP) located in the first chromatic separation lens layer (200A) and the nano post (NP) located in the second chromatic separation lens layer (200B) may be different. That is, the nano post (NP) located in the first chromatic separation lens layer (200A) may have a refractive index of the first refractive layer (201) greater than the refractive index of the second refractive layer (203), and the nano post (NP) located in the second chromatic separation lens layer (200B) may have a refractive index of the first refractive layer (201) smaller than the refractive index of the second refractive layer (203). Conversely, the nano post (NP) located in the first chromatic separation lens layer (200A) may have a refractive index of the first refractive layer (201) smaller than the refractive index of the second refractive layer (203), and the nano post (NP) located in the second chromatic separation lens layer (200B) may have a refractive index of the first refractive layer (201) greater than the refractive index of the second refractive layer (203). That is, depending on the embodiment, the shape and refractive index of the nano post included in each chromatic separation lens layer may differ.

[0063] Additionally, FIG. 9 illustrates a configuration in which a nano post (NP) located in the first chromatic separation lens layer (200A) includes a first refractive layer (201) and a second refractive layer (203), and a nano post (NP) located in the second chromatic separation lens layer (200B) includes a first refractive layer (201) and a second refractive layer (203), but the shape of the nano post in each chromatic separation lens layer may be different.

[0064] FIG. 10 illustrates the same region as FIG. 9 for another embodiment. With reference to FIG. 10, the image sensor according to the present embodiment is identical to the embodiment of FIG. 9 except that the nano post (NP) located in the first chromatic separation lens layer (200A) includes a first refractive layer (201) and a second refractive layer (203), and the nano post (NP) located in the second chromatic separation lens layer (200B) includes the first refractive layer (201). A detailed description of the identical components is omitted.

[0065] FIG. 11 illustrates the same region as FIG. 10 for another embodiment. With reference to FIG. 11, the image sensor according to the present embodiment is identical to the embodiment of FIG. 10 except that the nano post (NP) located in the first chromatic separation lens layer (200A) includes a first refractive layer (201), and the nano post (NP) located in the second chromatic separation lens layer (200B) includes the first refractive layer (201) and the second refractive layer (203). A detailed description of the identical components is omitted.

[0066] Although some examples have been described above, the shapes of the first color separation lens layer (200A) and the second color separation lens layer (200B) may vary. Additionally, although an embodiment in which the color separation lens layer includes the first color separation lens layer (200A) and the second color separation lens layer (200B) has been described, this is merely an example, and the color separation lens layer may have three or more color separation lens layers stacked.

[0067] For the convenience of explanation, the structure of the image sensor has been described briefly above. Below, the structure of the image sensor will be described in more detail with reference to Fig. 12. Fig. 12 is a cross-sectional view briefly illustrating the structure of the image sensor.

[0068] Referring to FIG. 12, the image sensor may include a sensor substrate (100) comprising a plurality of first light-sensing cells (110) that detect a first wavelength and a plurality of second light-sensing cells (120) that detect light of a second wavelength different from the first wavelength. The first wavelength may be in the region of green light within the visible light wavelength band. The second wavelength may be in the region of blue light within the visible light wavelength band. In this figure, the third and fourth sensing cells are not shown, but they may be shown when viewed in a cross-sectional view in a different horizontal direction. The configuration of the sensor substrate (100) including the third and fourth sensing cells will be described in detail later in FIG. 15.

[0069] The image sensor according to the present embodiment may include at least two or more lower anti-reflection layers disposed on the upper surface of a sensor substrate (100). In FIG. 12, the lower anti-reflection layer is illustrated as including a first lower anti-reflection layer (121) and a second lower anti-reflection layer (122). However, the lower anti-reflection layer is not limited thereto and may include three or four or more lower anti-reflection layers. The lower anti-reflection layer can improve light utilization efficiency by reducing light reflected from the upper surface of the sensor substrate (100) among incident light. In other words, the lower anti-reflection layer helps light incident from the outside to be detected by the sensor substrate (100). Each of the first lower anti-reflection layer (121) and the second lower anti-reflection layer (122) may be formed with a thickness of 80 nm to 120 nm.

[0070] The image sensor may be positioned on the upper part of the sensor substrate (100) and may include a first color filter (303G) positioned on the first light-sensing cell (110) and a second color filter (303B) positioned on the second light-sensing cell (120). Although not illustrated, the image sensor may further include a third color filter positioned on the third pixel and a fourth color filter positioned on the fourth pixel. For example, the first color filter (303G) and the fourth color filter may be green color filters that transmit only green light, and the second color filter (303B) may be a blue color filter that transmits only blue light. Additionally, although not illustrated, the third color filter may be a red color filter that transmits only red light.

[0071] However, if the nanoposts (NPs) are capable of not only simple light concentration but also color separation, light that has already been color-separated to a significant degree proceeds toward the first to fourth sensing cells, so light loss may be minimal even when using a color filter. Using a color filter can further improve the color purity of the image sensor. However, the color filter is not an essential component, and it may be omitted if the color separation efficiency of the nanoposts (NPs) is sufficiently high.

[0072] The image sensor according to the present embodiment can provide a sufficient amount of light to the pixels even when the pixel size is reduced, because there is almost no light loss caused by a color filter, for example, an organic color filter. Therefore, it is possible to manufacture an ultra-high resolution, ultra-compact, high-sensitivity image sensor having hundreds of millions or more pixels. Such an ultra-high resolution, ultra-compact, high-sensitivity image sensor can be employed in various high-performance optical devices or high-performance electronic devices. Such electronic devices may be, for example, smartphones, mobile phones, personal digital assistants (PDAs), laptops, PCs, various portable devices, home appliances, security cameras, medical cameras, automobiles, Internet of Things (IoT) devices, and other mobile or non-mobile computing devices, but are not limited thereto.

[0073] Referring to FIG. 12, the image sensor according to the present embodiment may include a Bayer pattern (311) and a protective film (316) positioned between color filters. The Bayer pattern (311) may be positioned between adjacent color filters (303) to separate them from each other. For example, the Bayer pattern (311) may have a grid structure. The Bayer pattern (311) may include a material having a lower refractive index than the color filters (303). The Bayer pattern (311) may include an organic material. For example, the Bayer pattern (311) may be a polymer layer containing silica nanoparticles. Since the Bayer pattern (311) has a low refractive index, it can increase the amount of light incident on the sensor substrate (100) and reduce crosstalk between adjacent sensing cells. The protective film (316) may cover the surface of the Bayer pattern (311) with a substantially uniform thickness. The protective film (316) may include, for example, at least one single film or multiple films of an aluminum oxide film and a silicon carbide oxide film. The protective film (316) can protect the color filter (303) and perform a moisture absorption function.

[0074] As shown in FIG. 12, the Bayer pattern (311) may be positioned between the color filters and may not overlap with the lower surface of the color filters. The protective film (316) may also be positioned covering the Bayer pattern (311) and may not overlap with the lower surface of the color filters.

[0075] The description of the spacer layer (300) and the color separation lens layer (200) is the same as previously described and is therefore omitted. Then, the structure of the sensor substrate (100) will be described in more detail below with reference to FIG. 13. However, the structure of the sensor substrate (100) described below is merely an example, and the present invention is not limited thereto. FIG. 13 shows a portion of the cross-section of the sensor substrate (100).

[0076] Referring to FIG. 13, the sensor substrate (100) may include a photoelectric conversion layer (10) and a first wiring region (20). The photoelectric conversion layer (10) may include a first substrate (400) and a pixel separation pattern (450).

[0077] Referring to FIG. 13, the first substrate (400) may include a first surface (400a) and a second surface (400b) facing each other. Light may be incident on the second surface (400b) of the first substrate (400). The first wiring region (20) may be located on the first surface (400a) of the first substrate (400). The spacer layer (300) and the color separation lens layer (200) described above may be located on the second surface (400b) of the first substrate (400).

[0078] The first substrate (400) may be a semiconductor substrate or a silicon-on-insulator (SOI) substrate. For example, the semiconductor substrate may include, for example, a silicon substrate, a germanium substrate, or a silicon-germanium substrate. The first substrate (400) may include an impurity of a first conductivity type. For example, the impurity of the first conductivity type may be a p-type impurity such as aluminum (Al), boron (B), indium (In), and / or gallium (Ga).

[0079] The photoelectric conversion region (410) may be a region doped with a second type of impurity within the first substrate (400). The second type of impurity may have a conductivity opposite to that of the first type of impurity. The second type of impurity may include n-type impurities such as phosphorus, arsenic, bismuth, and / or antimony. For example, each photoelectric conversion region (410) may include a first region adjacent to the first surface (400a) and a second region adjacent to the second surface (400b). There may be a difference in impurity concentration between the first region and the second region of the photoelectric conversion region (410). Thus, the photoelectric conversion region (410) may have a potential gradient between the first surface (400a) and the second surface (400b) of the first substrate (400). As another example, the photoelectric conversion region (410) may not have a potential gradient between the first surface (400a) and the second surface (400b) of the first substrate (400).

[0080] The first substrate (400) and the photoelectric conversion region (410) can form a photodiode. That is, a photodiode can be formed by a pn junction between the first substrate (400) of the first conductivity type and the photoelectric conversion region (410) of the second conductivity type. The photoelectric conversion region (410) forming the photodiode can generate and accumulate photocharges in proportion to the intensity of incident light.

[0081] A transfer transistor (TX) may be located on the first surface (400a) of the first substrate (400). The transfer transistor (TX) may be electrically connected to the photoelectric conversion region (410). The transfer transistor (TX) may include a transfer gate (TG) and a floating diffusion region (FD).

[0082] A gate dielectric film (GI) may be located between the transmission gate (TG) and the first substrate (400). A gate spacer (GS) may be located on the sidewall of the transmission gate (TG). The gate spacer (GS) may include, for example, silicon nitride, silicon carbide nitride, or silicon oxide nitride.

[0083] The floating diffusion region (FD) may be adjacent to one side of the transmission gate (TG). The floating diffusion region (FD) may have a second conductivity type (e.g., n-type) opposite to that of the first substrate (400). Although not shown in FIG. 12, other transistors may be located on the first substrate (400) in addition to the transmission transistor (TX).

[0084] Referring to FIG. 13, the pixel isolation pattern (450) may be located within a first trench (TR1). The first trench (TR1) may be recessed from a first surface (400a) of the first substrate (400). The pixel isolation pattern (450) may extend from the first surface (400a) of the first substrate (400) toward a second surface (400b). The pixel isolation pattern (450) may be a deep trench isolation (DTI) film. The pixel isolation pattern (450) may penetrate the first substrate (400). The vertical height of the pixel isolation pattern (450) may be substantially the same as the vertical thickness of the first substrate (400). For example, the width of the pixel isolation pattern (450) may gradually decrease from the first surface (400a) of the first substrate (400) toward the second surface (400b).

[0085] The pixel separation pattern (450) may include a first separation pattern (451), a second separation pattern (453), and a capping pattern (455). The first separation pattern (451) may be located along the sidewall of the first trench (TR1). The first separation pattern (451) may, for example, include a silicon-based insulating material (e.g., silicon nitride, silicon oxide, or silicon oxynitride) or a high dielectric material (e.g., hafnium oxide or aluminum oxide). For another example, the first separation pattern (451) may include a plurality of layers, and each layer may include different materials. The first separation pattern (451) may have a lower refractive index than the first substrate (400). Accordingly, crosstalk between pixels (PX) located on the first substrate (400) may be prevented or reduced.

[0086] The second separation pattern (453) may be located within the first separation pattern (451). For example, the sidewalls of the second separation pattern (453) may be surrounded by the first separation pattern (451). The first separation pattern (451) may be located between the second separation pattern (453) and the first substrate (400). The second separation pattern (453) may be spaced apart from the first substrate (400) by the first separation pattern (451). Accordingly, when the image sensor is operated, the second separation pattern (453) may be electrically separated from the first substrate (400). The second separation pattern (453) may include a crystalline semiconductor material, for example, polycrystalline silicon. For example, the second separation pattern (453) may further include a dopant, said dopant may include an impurity of the first conductivity type or an impurity of the second conductivity type.

[0087] For example, the second separation pattern (453) may include doped polycrystalline silicon. Alternatively, the second separation pattern (453) may include an undoped crystalline semiconductor material. For example, the second separation pattern (453) may include undoped polycrystalline silicon. The term "undoped" may mean that no intentional doping process is performed. The dopant may include an n-type dopant and a p-type dopant.

[0088] A capping pattern (455) may be located on the lower surface of the second separation pattern (453). The capping pattern (455) may be positioned adjacent to the first surface (400a) of the first substrate (400). The capping pattern (455) may include a non-conductive material. For example, the capping pattern (455) may include a silicon-based insulating material (e.g., silicon nitride, silicon oxide, or silicon oxynitride) or a high dielectric material (e.g., hafnium oxide or aluminum oxide). Accordingly, the pixel separation pattern (450) can prevent photocharges generated by incident light incident on a pixel (PX) from being incident on an adjacent pixel (PX) by random drift. That is, the pixel separation pattern (450) can prevent crosstalk between pixels (PX).

[0089] The device isolation pattern (403) may be located within the first substrate (400). For example, the device isolation pattern (403) may be located within the second trench (TR2). The second trench (TR2) may be recessed from the first surface (400a) of the first substrate (400). The device isolation pattern (403) may be a shallow trench isolation (STI) film. The device isolation pattern (403) may define an active pattern. The upper surface of the device isolation pattern (403) may be located within the first substrate (400). The width of the device isolation pattern (403) may gradually decrease from the first surface (400a) to the second surface (400b) of the first substrate (400). The upper surface of the device isolation pattern (403) may be vertically spaced from the photoelectric conversion region (410). The device separation pattern (403) may include the same material as the first separation pattern (451) of the pixel separation pattern (450), in which case the boundary between the device separation pattern (403) and the first separation pattern (451) may not be visible. However, this is merely an example and the present invention is not limited thereto.

[0090] FIG. 13 illustrates a configuration in which the device separation pattern (403), the pixel separation pattern (450), and the first surface (400a) of the first substrate (400) are located on the same plane, but this is merely an example and the present embodiment is not limited thereto. For example, the device separation pattern (403), the pixel separation pattern (450), and the first surface (400a) of the first substrate (400) may not form a coplanar plane. The device separation pattern (403) and the pixel separation pattern (450) may be positioned protruding or recessed from the first surface (400a) of the first substrate (400).

[0091] Additionally, the upper surface of the element separation pattern (403) and the upper surface of the pixel separation pattern (450) are shown as flat, but this is an example, and the upper surface of the element separation pattern (403) and the upper surface of the pixel separation pattern (450) may include a curved surface.

[0092] The first wiring area (20) is located on the first surface (400a) of the first substrate (400) and may include a plurality of insulating layers (IL1, IL2, IL3), a plurality of wiring layers (CL1, CL2), and vias (VIA).

[0093] The insulating layer may include a first insulating layer (IL1), a second insulating layer (IL2), and a third insulating layer (IL3).

[0094] The first insulating layer (IL1) may cover the first surface (400a) of the first substrate (400). The first insulating layer (IL1) may cover the gate electrode (TG). The second insulating layer (IL2) may be located on the first insulating layer (IL1). The third insulating layer (IL3) may be located on the second insulating layer (IL2).

[0095] The first to third insulating layers (IL1, IL2, IL3) may include a non-conductive material. For example, the first to third insulating layers (IL1, IL2, IL3) may include a silicon-based insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

[0096] The first wiring area (20) may include a first wiring layer (CL1) and a second wiring layer (CL2). The first wiring layer (CL1) may be located within the second insulation layer (IL2). The second wiring layer (CL2) may be located within the third insulation layer (IL3).

[0097] A plurality of vias (VIA) may be located within the first insulating layer (IL1), the second insulating layer (IL2), and the third insulating layer (IL3). The vias (VIA) may connect the floating diffusion region (FD), the first wiring layer (CL1), and the second wiring layer (CL2) to each other.

[0098] The first wiring layer (CL1), the second wiring layer (CL2), and the via (VIA) may include a metallic material. For example, the first wiring layer (CL1), the second wiring layer (CL2), and the via (VIA) may include copper (Cu).

[0099] Then, the components of the pixel array will be described in more detail below with reference to FIGS. 14 to 17.

[0100] FIGS. 14 and 15 are plan views showing the arrangement of pixels and the arrangement of light-sensing cells corresponding to pixel areas in an image sensor according to the present embodiment, FIG. 16 is a plan view showing the arrangement of nano posts in the chromatic separation lens layer of an image sensor according to the present embodiment, and FIG. 17 is an enlarged plan view showing an enlarged portion of FIG. 16.

[0101] Referring to FIGS. 14 to 17 and FIG. 3, the pixel array may include a sensor substrate (100) and a color separation lens layer (200).

[0102] The sensor substrate (100) may include a plurality of light-sensing cells (110, 120) that sense light. A color separation lens layer (200) may be disposed on the upper surface of the sensor substrate (100) at a predetermined distance apart.

[0103] A sensor substrate (100) may include a first light-sensing cell (110), a second light-sensing cell (120), a third light-sensing cell (130), and a fourth light-sensing cell (140) that convert light into an electrical signal. The first light-sensing cell (110) and the second light-sensing cell (120) may be alternately arranged along a first direction (X direction) as shown in FIG. 15. Additionally, the third light-sensing cell (130) and the fourth light-sensing cell (140) may also be alternately arranged along the first direction (X direction). Meanwhile, the first light-sensing cell (110) and the third light-sensing cell (130) may be alternately arranged along a second direction (Y direction), and the second light-sensing cell (120) and the fourth light-sensing cell (140) may also be alternately arranged along the second direction (Y direction). This area division may be intended to sense incident light by dividing it into pixel units.

[0104] For example, the first light-sensing cell (110) and the fourth light-sensing cell (140) can sense light of the first spectrum corresponding to the first pixel (P1), the second light-sensing cell (120) can sense light of the second spectrum corresponding to the second pixel (P2), and the third light-sensing cell (130) can sense light of the third spectrum corresponding to the third pixel (P3). For example, the light of the first spectrum may be green light, the light of the second spectrum may be blue light, and the light of the third spectrum may be red light. However, it is not limited thereto.

[0105] The chromatic separation lens layer (200) may include a plurality of nano posts (NPs) arranged according to a predetermined rule. Here, the rule may be applied to parameters such as the shape, size (width, height), spacing, and arrangement form of the nano posts (NPs). These parameters may be determined according to the target phase distribution that the chromatic separation lens layer (200) intends to achieve for the incident light. The target phase distribution may refer to the phase distribution at a position immediately after the incident light passes through the chromatic separation lens layer (200). However, the nano posts (NPs) may be arranged irregularly. The description of the nano posts (NPs) is the same as previously described. A detailed description of identical components is omitted.

[0106] The nano post (NP) may have shape dimensions of a subwavelength. A subwavelength may refer to a value smaller than the wavelength of the incident light, that is, the light intended to form the required phase distribution. In other words, at least one of the dimensions defining the shape of the nano post (NP) may be a subwavelength. For example, in the image sensor (1000) of the present embodiment, the nano post (NP) may have a cylindrical shape, and the height and diameter of the cylinder may be approximately 200 nm. However, the dimensions of the nano post (NP) are not limited thereto.

[0107] As shown in FIG. 2, the nano post (NP) can be supported by a spacer layer (300) interposed between it and the sensor substrate (100). The description of the spacer layer (300) is the same as previously described and is therefore omitted.

[0108] A nano post (NP) having a difference in refractive index from surrounding material can change the phase of light passing through the nano post (NP). This may be due to a phase delay caused by the shape dimensions of the nano post (NP) at a subwavelength. The degree of phase delay can be determined by the detailed shape dimensions and arrangement form of the nano post (NP). The color separation lens layer (200) can implement the required phase distribution for incident light by appropriately setting the degree of phase delay occurring in each of the plurality of nano posts (NP).

[0109] That is, the shape, size, and arrangement of a plurality of nano posts (NPs) can be determined to form an appropriate phase distribution. Through the formation of this phase distribution, the plurality of nano posts (NPs) can concentrate light of different spectra into adjacent first light-sensing cells (110) and second light-sensing cells (120). Additionally, through the formation of this phase distribution, the plurality of nano posts (NPs) can concentrate light of different spectra into adjacent third light-sensing cells (130) and fourth light-sensing cells (140).

[0110] As illustrated in FIGS. 15 and 16, the color separation lens layer (200) can be classified into a plurality of regions (210, 220, 230, 240) that correspond one-to-one with and face a plurality of light-sensing cells (110, 120, 130, 140). One or more nano posts (NPs) may be disposed in each of the plurality of regions (210, 220, 230, 240). At least one of the shape, size, and arrangement of the nano posts (NPs) may vary depending on the region.

[0111] A first region (210) and a first light-sensing cell (110) may be arranged to correspond to each other, and a second region (220) and a second light-sensing cell (120) may be arranged to correspond to each other. Additionally, a third region (230) and a third light-sensing cell (130) may be arranged to correspond to each other, and a fourth region (240) and a fourth light-sensing cell (140) may be arranged to correspond to each other.

[0112] The color separation lens layer (200) may include a plurality of unit pattern arrays arranged in two dimensions. Each unit pattern array may include four regions arranged in a 2×2 shape, for example, a first region (210), a second region (220), a third region (230), and a fourth region (240).

[0113] In FIGS. 15 and 16, a plurality of regions (210, 220, 230, 240) and a plurality of light-sensing cells (110, 120, 130, 140) are shown facing each other in the vertical direction with the same size. However, this is exemplary and is not limited to this structure. For example, a plurality of regions defined in a different form may correspond to a plurality of light-sensing cells. This is also true for other embodiments below.

[0114] The color separation lens layer (200) may be divided into regions such that light of the first spectrum is branched and concentrated to the first light-sensing cell (110) and the fourth light-sensing cell (140), light of the second spectrum is branched and concentrated to the second light-sensing cell (120), and light of the third spectrum is branched and concentrated to the third light-sensing cell (130). Additionally, for this purpose, the size, shape, and arrangement of nano posts (NP) may be determined for each region.

[0115] As illustrated in FIG. 14, the pixel array of the pixel array may be an arrangement similar to a Bayer pattern. A single unit pixel may include four quadrant regions. For example, the quadrant regions may be assigned to two first pixels (P1), one second pixel (P2), and one third pixel (P3). These unit pixels may be arranged two-dimensionally in a repeating pattern along a first direction (X direction) and a second direction (Y direction).

[0116] In a unit pixel of a 2×2 array, two first pixels (P1) may be arranged in one diagonal direction, and one second pixel (P2) and one third pixel (P3) may be arranged in the other diagonal direction. Looking at the overall pixel arrangement, a first row in which the first pixel (P1) and the second pixel (P2) are alternately arranged along the first direction (X direction), and a second row in which the third pixel (P3) and the first pixel (P1) are alternately arranged along the first direction (X direction), may be repeatedly arranged along the second direction (Y direction).

[0117] The colors of the first pixel (P1), the second pixel (P2), and the third pixel (P3) may not each be fixed to a single color. The colors or wavelength distributions of the first pixel (P1), the second pixel (P2), and the third pixel (P3) may each be represented as the first spectrum, the second spectrum, and the third spectrum.

[0118] Referring to FIG. 15, a plurality of first light-sensing cells (110), second light-sensing cells (120), and third light-sensing cells (130) can be arranged in a two-dimensional array along a first direction (X direction) and a second direction (Y direction) such that a row in which a first light-sensing cell (110) and a second light-sensing cell (120) are alternately arranged and a row in which a third light-sensing cell (130) and a fourth light-sensing cell (140) are alternately arranged are repeated with each other. Accordingly, a first light-sensing cell (110) or a fourth light-sensing cell (140) may correspond to a first pixel (P1), a second light-sensing cell (120) may correspond to a second pixel (P2), and a third light-sensing cell (130) may correspond to a third pixel (P3).

[0119] Referring together to FIGS. 14 to 16, a first light-sensing cell (110) and a first region (210) may correspond to a first pixel (P1), and a fourth light-sensing cell (140) and a fourth region (240) may correspond to another first pixel (P1). Additionally, a second light-sensing cell (120) and a second region (220) may correspond to a second pixel (P2), and a third light-sensing cell (130) and a third region (230) may correspond to a third pixel (P3).

[0120] Additionally, as shown in FIG. 16, nano posts (NPs) with different cross-sectional areas are placed at the center of the first pixel (P1), the second pixel (P2), and the third pixel (P3), and nano posts (NPs) may also be placed at the center of the pixel boundary line and at the intersection of the pixel boundary line. The cross-sectional area of ​​the nano posts (NPs) placed at the pixel boundary may be smaller than the cross-sectional area of ​​the nano posts (NPs) placed at the center of the pixel.

[0121] FIG. 17 illustrates in detail the arrangement of nanoposts (NPs) in parts of FIG. 16, namely, the first to fourth regions (210, 220, 230, 240) constituting the unit pattern array. That is, in FIG. 17, the nanoposts (NPs) are labeled p1 to p9 according to their detailed positions within the unit pattern array.

[0122] Referring to FIG. 17 for a more detailed explanation, the cross-sectional area of ​​the nano post (NP) placed in the center of the first region (210) and the nano post (p4) placed in the center of the fourth region (240) may be larger than the cross-sectional area of ​​the nano post (p2) placed in the center of the second region (220) or the nano post (p3) placed in the center of the third region (230). Additionally, the cross-sectional area of ​​the nano post (p2) placed in the center of the second region (220) may be larger than the cross-sectional area of ​​the nano post (p3) placed in the center of the third region (230). However, this is merely one example, and nano posts (NP) of various shapes, sizes, and arrangements may be applied as needed. Here, the cross-sectional area may refer to the area of ​​the cross-section perpendicular to the third direction (Z direction) of the nano post (NP).

[0123] The nano posts (NPs) provided in the first and fourth regions (210, 240) may have different distribution rules along the first direction (X direction) and the second direction (Y direction). For example, the nano posts (NPs) placed in the first and fourth regions (210, 240) may have different size arrangements along the first direction (X direction) and the second direction (Y direction). That is, as shown in FIG. 17, among the nano posts (NPs), the cross-sectional area of ​​the nano post (p5) located at the boundary between the first region (210) and the second region (220) adjacent in the first direction (X direction), and the cross-sectional area of ​​the nano post (p6) located at the boundary between the third region (230) adjacent in the second direction (Y direction) may be different from each other. Likewise, the cross-sectional area of ​​the nano post (p7) located at the boundary between the fourth region (240) and the third region (230) adjacent in the first direction (X direction) and the cross-sectional area of ​​the nano post (p8) located at the boundary between the second region (220) adjacent in the second direction (Y direction) may be different from each other.

[0124] On the other hand, the nano posts (NP) placed in the second region (220) corresponding to the second pixel (P2) and the third region (230) corresponding to the third pixel (P3) may have a symmetric distribution rule along the first direction (X direction) and the second direction (Y direction). That is, as shown in FIG. 17, among the nano posts (NP), the cross-sectional area of ​​the nano post (p5) placed at the boundary between the second region (220) and the adjacent pixel in the first direction (X direction) and the nano post (p8) placed at the boundary between the adjacent pixel in the second direction (Y direction) are equal to each other, and in the third region (230), the cross-sectional area of ​​the nano post (p7) placed at the boundary between the adjacent pixel in the first direction (X direction) and the nano post (p6) placed at the boundary between the adjacent pixel in the second direction (Y direction) may also be equal to each other.

[0125] Meanwhile, the nanoposts (p9) placed at the four corners of each of the first region (210), second region (220), third region (230), and fourth region (240), that is, at the positions where the four regions intersect, may all have the same cross-sectional area. This distribution may be attributed to a pixel arrangement similar to a Bayer pattern. While the second pixel (P2) and the third pixel (P3) are identical in that the pixels adjacent in the first direction (X direction) and the second direction (Y direction) are the same as the first pixel (P1), the first pixel (P1) corresponding to the first region (210) is different in that the pixel adjacent in the first direction (X direction) is the second pixel (P2) and the pixel adjacent in the second direction (Y direction) is the third pixel (P3), and the pixel adjacent in the second direction (Y direction) is the second pixel (P3). The pixels (P2) may be different from each other. Additionally, the first pixel (P1) corresponding to the first area (210) and the fourth area (240) may have the same first pixel (P1) as the pixels adjacent in the four diagonal directions, the second pixel (P2) corresponding to the second area (220) may have the same third pixel (P3) as the pixels adjacent in the four diagonal directions, and the third pixel (P3) corresponding to the third area (230) may have the same second pixel (P2) as the pixels adjacent in the four diagonal directions.

[0126] Accordingly, in the second region (220) and the third region (230) corresponding to the second pixel (P2) and the third pixel (P3), respectively, nano posts (NP) may be arranged in a 4-fold symmetry form, and in the first and fourth regions (210, 240) corresponding to the first pixel (P1), nano posts (NP) may be arranged in a 2-fold symmetry form. In particular, the first region (210) and the fourth region (240) may be rotated 90° relative to each other.

[0127] Although it is shown that multiple nano posts (NPs) all have a symmetric circular cross-sectional shape, they are not limited thereto. For example, some nano posts (NPs) having an asymmetric cross-sectional shape may be included. Specifically, in the first region (210) and the fourth region (240) corresponding to the first pixel (P1), nano posts (NPs) having an asymmetric cross-sectional shape with different widths in the first direction (X direction) and the second direction (Y direction) may be employed, and in the second region (220) and the third region (230) corresponding to the second pixel (P2) and the third pixel (P3), respectively, nano posts (NPs) having a symmetric cross-sectional shape with the same width in the first direction (X direction) and the second direction (Y direction) may be employed.

[0128] However, the shape and arrangement of such nano posts (NPs) are merely examples, and the present invention is not limited thereto. The nano posts (NPs) may be arranged irregularly.

[0129] The arrangement rule of the exemplified color separation lens layer (200) may be an example in which a target phase distribution is implemented at a position immediately after passing through the color separation lens layer (200), such that light of the first spectrum is branched and concentrated to the first light sensing cell (110) and the fourth light sensing cell (140), light of the second spectrum is branched and concentrated to the second light sensing cell (120), and light of the third spectrum is branched and concentrated to the third light sensing cell (130). However, the arrangement rule of the color separation lens layer (200) is not limited to the illustrated pattern.

[0130] The shape, size, and arrangement of nano posts (NPs) provided in each region of the color separation lens layer (200) can be determined so that at a location passing through the color separation lens layer (200), light of a first wavelength is concentrated into the first light detection cell (110) and the fourth light detection cell (140), and does not proceed to the adjacent second light detection cell (120) and third light detection cell (130).

[0131] Likewise, the shape, size, and arrangement of nano posts (NPs) provided in each region of the color separation lens layer (200) can be determined so as to form a phase in which light of a second wavelength is concentrated into a second light detection cell (120) at a location that has passed through the color separation lens layer (200), and a phase in which it does not proceed to the adjacent first light detection cell (110), third light detection cell (130), and fourth light detection cell (140).

[0132] In addition, the shape, size, and arrangement of nano posts (NP) provided in each region of the color separation lens layer (200) can be determined so as to form a phase in which light of a third wavelength is concentrated into a third light detection cell (130) at a location that has passed through the color separation lens layer (200) and does not proceed to the adjacent first light detection cell (110), second light detection cell (120), and fourth light detection cell (140).

[0133] The chromatic separation lens layer (200) can cause light immediately after passing through the chromatic separation lens layer (200) to have the following target phase distribution. That is, at a position immediately after passing through the chromatic separation lens layer (200), in other words, at the lower surface of the chromatic separation lens layer (200) or the upper surface of the spacer layer (300), the phase of light of the first wavelength can be 2Nπ at the center of the first region (210) corresponding to the first light-sensing cell (110) and at the center of the fourth region (240) corresponding to the fourth light-sensing cell (140). Additionally, it can be (2N-1)π at the center of the second region (220) corresponding to the second light-sensing cell (120) and at the center of the third region (230) corresponding to the third light-sensing cell (130). Here, N is an integer greater than 0. In other words, the phase of the first wavelength of light at the position immediately after passing through the chromatic separation lens layer (200) is maximum at the center of the first region (210) and the center of the fourth region (240), and gradually decreases in a concentric manner as it moves away from the center of the first region (210) and the center of the fourth region (240), so that it can be minimum at the center of the second region (220) and the center of the third region (230). Specifically, for example, when N=1, the phase of the first wavelength of light at the position after passing through the chromatic separation lens layer (200) is 2π at the center of the first region (210) and the center of the fourth region (240), and can be π at the center of the second region (220) and the center of the third region (230). Here, the phase may refer to a phase value relative to the phase immediately before the light passes through the nano post (NP).

[0134] Additionally, at the position immediately after passing through the color separation lens layer (200), the phase of the light of the second wavelength may be 2Mπ at the center of the second region (220) corresponding to the second light-sensing cell (120), and (2M-1)π at the center of the first region (210) corresponding to the first light-sensing cell (110) and at the center of the fourth region (240) corresponding to the fourth light-sensing cell (140). Additionally, at the center of the third region (230) corresponding to the third light-sensing cell (130), it may be greater than (2M-2)π and smaller than (2M-1)π. Here, M is an integer greater than 0. In other words, the phase of the second wavelength light at the position immediately after passing through the chromatic separation lens layer (200) is maximum at the center of the second region (220), and gradually decreases in a concentric manner as it moves away from the center of the second region (220), so that it can be locally minimum at the center of the first region (210), the fourth region (240), and the third region (230). Specifically, for example, when M=1, the phase of the second wavelength light at the position after passing through the chromatic separation lens layer (200) is 2π at the center of the second region (220), π at the center of the first region (210) and the center of the fourth region (240), and can be about 0.2π to 0.7π at the center of the third region (230).

[0135] Likewise, at the position immediately after passing through the chromatic separation lens layer (200), the phase of the light of the third wavelength is 2Lπ at the center of the third region (230) corresponding to the third light-sensing cell (130), (2L-1)π at the center of the first region (210) corresponding to the first light-sensing cell (110) and the fourth region (240) corresponding to the fourth light-sensing cell (140), and may be greater than (2L-2)π and less than (2L-1)π at the center of the second region (220) corresponding to the second light-sensing cell (120). Here, L is an integer greater than 0. In other words, the phase of the third wavelength of light at the position immediately after passing through the chromatic separation lens layer (200) is maximum at the center of the third region (230), and gradually decreases in a concentric manner as it moves away from the center of the third region (230), and can be locally minimum at the center of the first region (210), the fourth region (240), and the second region (220). Specifically, for example, when L=1, the phase of the third wavelength at the position after passing through the chromatic separation lens layer (200) is 2π at the center of the third region (230), π at the center of the first region (210) and the center of the fourth region (240), and can be about 0.2π to 0.7π at the center of the second region (220).

[0136] The light of the first wavelength, the light of the second wavelength, and the light of the third wavelength may be green light, blue light, and red light, respectively. However, they are not limited thereto. As previously mentioned, the target phase distribution may refer to the phase distribution at a position immediately after passing through the color separation lens layer (200). Additionally, when the light of this phase distribution travels toward a plurality of light sensing cells (110, 120, 130, 140), it may form different wavelength spectra depending on the distance traveled.

[0137] Then, a method for manufacturing an image sensor according to one embodiment will be described below with reference to the drawings. FIGS. 18 to 21 are cross-sectional views schematically showing the process of a method for manufacturing an image sensor according to one embodiment of the present invention. The description will be made with reference to FIGS. 2 and FIGS. 3, and previously explained contents will be briefly explained or omitted.

[0138] Referring to FIG. 18, a sensor substrate (100) and a spacer layer (300) are formed. The sensor substrate (100) may include a plurality of light-sensing cells. The description of the sensor substrate (100) and the spacer layer (300) is the same as previously described and is therefore omitted.

[0139] Subsequently, an intermediate layer (500) is formed on the spacer layer (300). The intermediate layer (500) may include Al2O3, but is not limited thereto. Depending on the embodiment, the intermediate layer (500) may be omitted.

[0140] Next, a dielectric material layer for the dielectric layer (205) is formed on the intermediate layer (500). The dielectric material layer may include a low refractive index material, such as SiO2. However, the material of the dielectric material layer is not limited to SiO2. Subsequently, a photoresist (PR) pattern is formed on the dielectric material layer through a photo process, and the dielectric material layer is etched using the PR pattern as a mask to form the dielectric layer (205). At this time, a plurality of openings (OP) may be formed in the dielectric layer (205). As shown in FIG. 18, the width of the plurality of openings (OP) may vary. In FIG. 18, the width (D3) of the opening (OP) is shown.

[0141] Next, referring to FIG. 19, after the dielectric layer (205) is formed, a second material layer (203a) covering the intermediate layer (500) and the dielectric layer (205) is formed. The second material layer (203a) can be formed to a very thin thickness through an Atomic Layer Deposition (ALD) process. For example, the thickness (D1) of the second material layer (203a) can be 5 nm to 30 nm.

[0142] The second material layer (203a) may include a material with a refractive index equal to or higher than that of the dielectric layer (205). The second material layer (203a) may include the same material as the dielectric layer (205), and may include, for example, SiO2. Alternatively, the second material layer (203a) may include SiO2 or Al2O3. However, these materials are examples and the present invention is not limited thereto.

[0143] As shown in FIG. 19, since a second material layer (203a) is formed on both sides of the opening (OP), the width (D2) of the opening (OP) is reduced by the thickness (D1) of the second material layer (203a) from the width (D3) formed in FIG. 13.

[0144] Next, referring to FIG. 20, after forming a second material layer (203a), a first material layer (201a) covering the second material layer (203a) is formed. The first material layer (201a) can be formed with a relatively high thickness. For example, the first material layer (201a) can be formed with a thickness that completely fills the groove formed by the dielectric layer (205) and the second material layer (203a). The first material layer (201a) can be formed from a material that has excellent light transmittance and a high refractive index. The refractive index of the first material layer (201a) can be higher than the refractive index of the second material layer (203a). Additionally, the refractive index of the first material layer (201a) can be higher than the refractive index of the dielectric layer (205). For example, the first material layer (201a) can be formed from TiO2. However, this is just one example, and the first material layer (201a) may include any one of SiN3, Si3N4, ZnS, GaN, ZnSe, TiO2, and hydrogen-doped amorphous silicon (a-Si:H). The width (D2) of the first material layer (201a) in the region where the opening was located may be 50 nm to 250 nm.

[0145] Next, referring to FIG. 21, after forming a first material layer (201a), a nano post (NP) is formed through a CMP process. In the CMP process, the dielectric layer (205) can act as an etch stop layer. Through the CMP process, the first material layer (201a) can be separated from one another into a plurality of first refractive layers (201), and the second material layer (203a) can also be separated from one another into a plurality of second refractive layers (203). The separated first refractive layers (201) and second refractive layers (203) can form a nano post (NP).

[0146] The width (D2) of the first refractive layer (201) in the formed nano post (NP) may be 50 nm to 250 nm. This is smaller than the width (D3) of the aperture (OP) formed in the patterning step of the dielectric layer (205) mentioned earlier. That is, by this manufacturing method, a first refractive layer (201) having a narrower width than the finest pattern formed in the patterning step of the dielectric layer (205) can be formed.

[0147] As the resolution of the image sensor increases, the size of a single pixel becomes smaller, and it is necessary to form individual nano posts (NPs) with smaller sizes. However, the process of forming such fine patterns is not easy. Since the formation of nano posts (NPs) occurs after the formation of the sensor substrate (100), it is difficult to use a high-temperature process of 250°C or higher during the nano post (NP) formation process. Therefore, there are limitations when selecting a hard mask to form fine patterns.

[0148] However, in the present embodiment, after forming and patterning the dielectric layer (205), the second refractive layer (203) is formed by ALD (Atomic Layer Deposition). Accordingly, the width of the formed opening (OP) is reduced by the thickness of the second refractive layer (203), and a first refractive layer (201) having a small width can be formed.

[0149] FIG. 22 is a block diagram of an electronic device including an image sensor according to an embodiment of the present invention. It will be described with reference to FIG. 1, and previously described contents will be briefly explained or omitted.

[0150] Referring to FIG. 22, the electronic device (2000, hereinafter simply referred to as the "electronic device") including the image sensor of the present embodiment may include an imaging unit (2100), an image sensor (1000), and a processor (2200). The electronic device (2000) may be, for example, a camera. The imaging unit (2100) may form an optical image by focusing light reflected from an object (OBJ). The imaging unit (2100) may include an objective lens (2010), a lens driving unit (2120), an aperture (2130), and an aperture driving unit (2140). In FIG. 22, only one lens is shown as a representative example for convenience, but in reality, the objective lens (2010) may include a plurality of lenses of different sizes and shapes. In some embodiments, the electronic device (2000) may be a mobile camera, and in the mobile camera, the aperture (2130) and the aperture driving unit (2140) may be omitted.

[0151] The lens driving unit (2120) can communicate information regarding focus detection with the processor (2200) and can adjust the position of the objective lens (2010) according to a control signal provided by the processor (2200). The lens driving unit (2120) can move the objective lens (2010) to adjust the distance between the objective lens (2010) and the subject (OBJ), or adjust the position of each individual lens not shown within the objective lens (2010). By driving the objective lens (2010) with the lens driving unit (2120), the focus on the subject (OBJ) can be adjusted. This electronic device (2000) may be equipped with an autofocus function.

[0152] The aperture driving unit (2140) can communicate information regarding the amount of light with the processor (2200) and can control the aperture (2130) according to a control signal provided by the processor (2200). For example, the aperture driving unit (2140) can increase or decrease the aperture opening of the aperture (2130) according to the amount of light entering the interior of the electronic device (2000) through the objective lens (2010). In addition, the aperture driving unit (2140) can control the opening time of the aperture (2130).

[0153] An image sensor (1000) can generate an electrical image signal based on the intensity of incident light. The image sensor (1000) may be, for example, the image sensor (1000) of FIG. 1. Accordingly, the image sensor (1000) may include a pixel array (1140), a timing generator (1120), and a readout circuit (1150). Light passing through the objective lens (2010) and the aperture (2130) can form an image of a subject (OBJ) on the light-receiving surface of the pixel array (1100). The pixel array (1100) may be a CCD or CMOS that converts an optical signal into an electrical signal. The pixel array (1100) may include additional pixels to perform an AF function or a distance measurement function.

[0154] The processor (2200) can control the overall operation of the electronic device (2000) and can be equipped with an image processing function.

[0155] For example, the processor (2200) can provide control signals for the operation of each component, such as the lens drive unit (2120), aperture drive unit (2140), and timing generator (1120).

[0157] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention. Explanation of the symbols

[0159] 100: Sensor board 200: Color separation lens layer 205: Genome layer NP: Nanopost 201: First refractive layer 203: Second refractive layer

Claims

Claim 1 An image sensor comprising: a sensor substrate including a photoelectric conversion region; a spacer layer located on the sensor substrate; and a chromatic separation lens layer located on the spacer layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer and a second refractive layer, wherein the second refractive layer is located along the bottom surface and side surface of the first refractive layer, and the refractive index of the first refractive layer is greater than the refractive index of the second refractive layer. Claim 2 An image sensor according to claim 1, wherein the refractive index of the second refractive layer is greater than the refractive index of the dielectric layer. Claim 3 In claim 1, the image sensor comprising the same material as the dielectric layer as the second refractive layer. Claim 4 An image sensor according to claim 1, wherein the thickness of the second refractive layer is 5 nm to 30 nm. Claim 5 An image sensor according to claim 1, wherein the maximum planar width of the first refractive layer is 50 nm to 250 nm. Claim 6 An image sensor according to claim 1, wherein the color separation lens layer comprises a first color separation lens layer and a second color separation lens layer positioned overlapping each other, the first color separation lens layer comprises a plurality of nano posts and a dielectric layer positioned between the nano posts, and the second color separation lens layer comprises a plurality of nano posts and a dielectric layer positioned between the nano posts. Claim 7 An image sensor comprising: a sensor substrate including a photoelectric conversion region; a spacer layer located on the sensor substrate; and a chromatic separation lens layer located on the spacer layer, wherein the chromatic separation lens layer comprises a plurality of nanoposts and a dielectric layer located between the plurality of nanoposts, wherein the nanoposts comprise a first refractive layer, and the dielectric layer is located on the bottom surface and side surface of the first refractive layer, and the bottom surface of the dielectric layer is located closer to the spacer layer than the bottom surface of the first refractive layer. Claim 8 In claim 7, an image sensor in which the refractive index of the first refractive layer is greater than the refractive index of the dielectric layer. Claim 9 An image sensor according to claim 7, wherein the thickness of the dielectric layer located on the bottom surface of the first refractive layer is 5 nm to 30 nm. Claim 10 In claim 7, an image sensor in which the maximum planar width of the first refractive layer is 50 nm to 250 nm.

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