Image sensing device

Abstract

An image sensing apparatus is disclosed. In an embodiment, an image sensing apparatus includes: a semiconductor substrate including a photoelectric conversion element configured to generate photoelectric charges by converting incident light; and a metasurface lens layer disposed over the semiconductor substrate and configured to separate incident light into light components of different colors based on wavelengths and converge the separated light components onto the corresponding photoelectric conversion elements. The metamaterial lens layer may include: a first metamaterial lens layer including first nanostructures and a first air layer disposed between the first nanostructures; a second metamaterial lens layer including second nanostructures and a second air layer disposed between the second nanostructures, where at least a portion of each of the second nanostructures is disposed on a corresponding one of the first nanostructures; and a support layer disposed in a space between adjacent ones of the first nanostructures over the first air layer.

Description

Technical Field

[0001] The technology and implementation disclosed in this patent document generally relate to an image sensing device comprising one or more metalenses. Background Technology

[0002] Meta-optics refers to the field of optical technology that utilizes nanostructures with wavelengths smaller than light to achieve novel optical properties that cannot be achieved using traditional materials.

[0003] An image sensor is a device that converts optical images into electrical signals. Each pixel in an image sensor includes microlenses and color filters. With the increasing demand for high-resolution cameras, pixel sizes are becoming smaller. As a result, the size of the microlenses and color filters within the pixels is also increasing, leading to a decrease in optical efficiency.

[0004] To overcome these limitations, active research is underway on metalenses based on meta-optics applicable to image sensors. Summary of the Invention

[0005] Various embodiments of the disclosed technology relate to an image sensing device capable of improving the degradation of quantum efficiency (QE) caused by oblique incident light.

[0006] In embodiments of the disclosed technology, an image sensing device may include: a semiconductor substrate including a photoelectric conversion element configured to generate photocharge by converting incident light; and a metalens layer disposed above the semiconductor substrate and configured to separate incident light into light components of different colors based on wavelength, and to converge the separated light components onto corresponding photoelectric conversion elements. The metalens layer may include: a first metalens layer including a first nanostructure and a first air layer disposed between the first nanostructures; a second metalens layer including a second nanostructure and a second air layer disposed between the second nanostructures, wherein at least a portion of each second nanostructure is disposed on a corresponding first nanostructure within the first nanostructure; and a support layer disposed above the first air layer in the space between adjacent first nanostructures within the first nanostructure.

[0007] In another embodiment of the disclosed technology, an image sensing device may include: a semiconductor substrate including a photoelectric conversion element configured to generate photocharge by converting incident light; a plurality of first nanostructures disposed above the semiconductor substrate; a first air layer disposed between adjacent first nanostructures among the plurality of first nanostructures; a support layer disposed between the first nanostructures such that at least a portion of adjacent first nanostructures is exposed; a plurality of second nanostructures disposed above the first nanostructures; and a second air layer disposed between the second nanostructures.

[0008] It will be understood that both the above general description and the following detailed description of the disclosed technology are illustrative and explanatory, and are intended to provide further explanation of the claimed disclosure. Attached Figure Description

[0009] The above and other features and advantages of the disclosed technology will become readily apparent when considered in conjunction with the accompanying drawings, with reference to the following detailed description.

[0010] Figure 1 This is a block diagram illustrating examples of image sensing devices based on some implementations of the disclosed technology.

[0011] Figure 2 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 1 A schematic diagram of an example structure of a metalens layer in the central portion of the pixel region shown.

[0012] Figure 3 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 1 A schematic diagram of an example structure of a metalens layer in the edge portion of the pixel region shown.

[0013] Figures 4 to 14 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 2 A cross-sectional view of an example method for the structure. Detailed Implementation

[0014] This patent document provides implementations and examples of an image sensing device comprising one or more metalenses, which can be used to substantially solve one or more technical or engineering problems and mitigate limitations or drawbacks encountered in some other image sensing devices. Some implementations of the disclosed technology provide examples of image sensing devices designed to improve the degradation of quantum efficiency (QE) caused by obliquely incident light. Recognizing the above-mentioned problems, the disclosed technology provides various implementations of image sensing devices that can improve the degradation of quantum efficiency (QE) relative to obliquely incident light on an image sensing device employing metalenses.

[0015] The following description refers in detail to specific embodiments, examples of which are shown in the accompanying drawings. Wherever possible, similar reference numerals and letters are used throughout the drawings to denote similar components. In the following description, detailed descriptions of related known configurations or functions will be omitted to avoid obscuring the subject matter.

[0016] Various embodiments will be described below with reference to the accompanying drawings. However, it should be understood that the disclosed technology is not limited to the specific embodiments, but encompasses various modifications, equivalents, and alternatives to these embodiments. Embodiments of the disclosed technology can provide various effects that can be directly or indirectly identified through this disclosure.

[0017] Figure 1 This is a block diagram illustrating examples of image sensing devices based on some implementations of the disclosed technology.

[0018] Reference Figure 1 The image sensing device may include a pixel area 100, a row driver 200, a correlated dual sampler (CDS) 300, an analog-to-digital converter (ADC) 400, an output buffer 500, a column driver 600, and a timing controller 700. Figure 1 The components of the image sensing device shown are discussed as examples only, and this patent document covers numerous other changes, substitutions, variations, alterations, and modifications. In this patent document, the term "pixel" may be used to refer to an image sensing pixel configured to detect incident light to generate an electrical signal carrying an image in the incident light.

[0019] Pixel region 100 may include a plurality of unit pixels (PX) arranged in a two-dimensional (2D) structure including rows and columns. Each unit pixel (PX) converts incident light into a corresponding electrical signal to generate a pixel signal and outputs the pixel signal to a correlated double sampler (CDS) 300 via column lines. Pixel region 100 may include a metalens, which acts as a color router for visible light. In the metalens, an air layer may be formed between adjacent nanopillars, and the nanopillars may be formed as a multilayer structure to prevent degradation of luminous efficiency caused by oblique incident light.

[0020] Pixel region 100 can receive drive signals (e.g., row selection signal, reset signal, transfer signal, etc.) from row driver 200. When a drive signal is received, a unit pixel can be enabled to perform operations corresponding to the row selection signal, reset signal, and transfer signal.

[0021] The line driver 200 can enable a unit pixel based on a control signal received from a controller circuit such as a timing controller 700.

[0022] The Correlated Double Sampler (CDS) 300 can use correlated double sampling to remove unwanted offset values ​​per unit pixel.

[0023] The ADC 400 can convert CDS signals received from the correlated dual sampler (CDS) 300 into digital signals.

[0024] The output buffer 500 can temporarily store column-based data received from the ADC 400 under the control of the timing controller 700.

[0025] The column driver 600 can select the column of the output buffer 500 under the control of the timing controller 700, and can sequentially output the data temporarily stored in the selected column of the output buffer 500.

[0026] The timing controller 700 generates signals for controlling the operation of the row driver 200, ADC 400, output buffer 500, and column driver 600. The timing controller 700 provides the row driver 200, column driver 600, ADC 400, and output buffer 500 with clock signals required for the operation of the various components of the image sensing device, control signals for timing control, and address signals for selecting rows or columns.

[0027] In some implementations, as described above, a metalens can function as a color router by spatially separating incident visible light based on its wavelength. This allows the metalens to guide different color components (e.g., red, green, and blue) toward corresponding photoelectric conversion elements. In some implementations, the metalens can replace a color filter array. In some implementations, this color routing function is achieved through a structure comprising multiple nanopillars arranged in a specific pattern. In some implementations, the metalens can control the propagation direction of different wavelengths by adjusting the height, diameter, and / or material composition of the nanopillars.

[0028] Metalenses utilize the phase difference between a high-refractive-index material (e.g., nanopillars) and a low-refractive-index material (e.g., air) to focus light of a specific wavelength onto a corresponding photoelectric conversion element or color filter, thereby maximizing the refractive index difference and allowing the height of the metalens to be reduced. In some implementations, light is incident at an oblique angle, but physically tilted nanopillars are impractical.

[0029] To address this issue, the disclosed technology can be implemented in some embodiments as a metalens structure, wherein the nanopillars are formed in vertically stacked layers, each layer being laterally displaced relative to the layer below it. In some implementations where the upper nanopillar is disposed on the lower nanopillar, an oxide layer is formed between the upper and lower nanopillars for structural support, and a support layer (e.g., an oxide layer) is formed between the upper and lower nanopillars.

[0030] Figure 2 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 1 A schematic diagram of an example structure of a metalens layer in the central portion of the pixel region shown. Figure 3 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 1 A schematic diagram of an example structure of a metalens layer in the edge portion of the pixel region shown.

[0031] Reference Figure 2 and Figure 3 The image sensing device may include a substrate layer 110, a color filter layer 120, a cover layer 130, an etch stop layer 140, and a metalens layer 150.

[0032] The substrate layer 110 may include a semiconductor substrate having a first surface and a second surface opposite to the first surface. From an internal perspective of the semiconductor substrate, the first and second surfaces face each other. In some implementations, the first surface is the surface on which light is incident, and a color filter layer 120, a capping layer 130, an etch stop layer 140, and a metalens layer 150 may be formed thereon. The semiconductor substrate may be in a single-crystal state and may include a silicon-containing material. That is, the semiconductor substrate may include a single-crystal silicon-containing material. The semiconductor substrate may include a photoelectric conversion element 112 that converts incident light received through the first surface of the semiconductor substrate into photocharge.

[0033] The color filter layer 120 may include a plurality of color filters arranged to correspond to a unit pixel. The color filters may be arranged in a Bayer pattern. The color filter layer 120 may include a grid structure disposed between the color filters to prevent crosstalk between them.

[0034] The capping layer 130 may be disposed above the color filter layer 120 and may operate as a planarization layer to eliminate the height difference between the mesh structure and the color filter. The capping layer 130 may comprise a material transparent to visible light, such as a nanostructure (nanopillar) with a refractive index lower than that of the metalens layer 150 and a dielectric material with low absorption in the visible spectrum (e.g., SiO2, siloxane-based spin-coated glass (SOG), etc.). The capping layer 130 may comprise a material and thickness that can achieve a target refractive index together with the etch stop layer 140. The target refractive index may be a theoretical refractive index designed for an effective medium disposed between two materials, such that light reflection occurring at the interface between materials with different refractive indices is minimized.

[0035] An etch stop layer 140 may be formed over the capping layer 130 and may serve as an etch stop to protect the capping layer 130 during an etch process for forming one or more first nanopillars 152a. The etch stop layer 140 may include an ultra-low temperature oxide (ULTO) layer.

[0036] The metalens layer 150 can converge (focus) incident light onto the photoelectric conversion element 112 of the substrate layer 110. For example, the metalens layer 150 can separate incident light into beams (or light components) of different colors corresponding to color filters arranged in a Bayer pattern, and can focus the separated light onto the photoelectric conversion element 112 of the corresponding unit pixel. Since the diffraction or scattering characteristics of light vary according to the wavelength of light, the metalens layer 150 can utilize these characteristics to separate the colors of the incident light from each other. The transmission direction of the separated beams can be adjusted according to the refractive index distribution of the metalens layer 150 and the shape of the nanopillars corresponding to each wavelength.

[0037] The meta-lens layer 150 may include a first meta-lens layer 152, a second meta-lens layer 154, and a support layer 156.

[0038] The first meta-lens layer 152 may include a first nanopillar 152a and an air layer 152b, and the second meta-lens layer 154 may include a second nanopillar 154a, a capping layer 154b and an air layer 154c.

[0039] Each of the first nanopillars 152a and each of the second nanopillars 154a can be formed into a pillar shape with a diameter smaller than the wavelength of the incident light. For example, the nanopillars (152a, 154a) can be formed into various pillar shapes, such as pillar shapes with cylindrical cross-sections, polygonal cross-sections, and elliptical cross-sections. An air layer 152b can be formed between the first nanopillars 152a, and an air layer 154c can be formed between the second nanopillars 154a.

[0040] The first nanopillar 152a and the second nanopillar 154a can be formed of the same material and can be stacked one-to-one to form the nanostructure of the metalens layer 150. For example, the nanopillars (152a, 154a) may include a high refractive index material (e.g., TiO2) and can be stacked on top of each other such that the bottom surface of the second nanopillar 154a contacts the top surface of the first nanopillar 152a. In this case, the second nanopillar 154a can be laterally shifted relative to the first nanopillar 152a corresponding to the principal ray angle (CRA) of the incident light. For example, as Figure 2 As shown, the second nanopillar 154a located at the center of pixel region 100 can be positioned such that the central axis of the second nanopillar 154a coincides with the central axis of the first nanopillar 152a, and as... Figure 3 As shown, the second nanopillar 154a located in the edge region of pixel region 100 can be positioned such that the central axis of the second nanopillar 154a can be shifted relative to the central axis of the first nanopillar 152a in response to the principal ray angle (CRA) in the corresponding region.

[0041] Stacked nanopillars (152a, 154a) can have the same shape and size. For example, stacked nanopillars (152a, 154a) can be formed into a column shape with the same diameter and height.

[0042] The stacked nanopillars (152a, 154a) can be arranged in a pattern that separates incident light according to color and allows the separated light to be focused on unit pixels of the corresponding color. For example, when the color filters of the unit pixels are arranged in a Bayer pattern, the nanopillars (152a, 154a) can be arranged to have a refractive index distribution that can form a phase profile that separates incident light according to the wavelengths of red, green, and blue and allows the separated light to be focused on unit pixels of the corresponding colors. The aforementioned refractive index distribution can be formed by the shape and arrangement of the nanopillars (152a, 154a) and can be obtained by the difference in refractive index between the nanopillars (152a, 154a) and the air layer (152b, 154c) (e.g., the material surrounding the nanopillars).

[0043] The metalens layer 150 based on the embodiment may include a structure in which multiple nanopillars (152a, 154a) are stacked, such that the upper nanopillar 154a is shifted to correspond to the CRA, thereby improving the degradation of quantum efficiency (QE) caused by oblique incident light. In the embodiment, when the nanopillars (152a, 154a) are formed in a stacked structure and the upper nanopillar 154a is shifted to correspond to the CRA, the degradation of quantum efficiency (QE) caused by oblique incident light can be reduced more effectively as the height of the nanopillars (152a, 154a) decreases. The metalens layer 150 based on the embodiment may allow air layers (152b, 154c) to be formed between the nanopillars (152a, 154a), which increases the difference in refractive index between the nanostructure and the surrounding material. Compared to the example case where a material with a higher refractive index than the air layer is used as the surrounding material, this larger refractive index difference allows the relative height of the nanopillars (152a, 154a) to be reduced.

[0044] The top and side surfaces of the second nanopillar 154a may be covered by a capping layer 154b. The capping layer 154b may include a low-temperature oxide (LTO) layer. Although for ease of description, the capping layer 154b is described as separate from the second support layer 156b, other configurations are possible. For example, the capping layer 154b and the second support layer 156b may be formed of the same material and may be formed together using the same deposition process. For example, the capping layer 154b covering the second nanopillar 154a may extend into the support layer 156 located below the air layer 154c to form the second support layer 156b.

[0045] A support layer 156 may be disposed between the first nanopillars 152a to expose the top surface of the first nanopillars 152a, and may support the second metalens layer 154. In an embodiment, when the nanopillars (152a, 154a) are formed in a stacked structure and the upper nanopillar 154a is shifted to correspond to the CRA, a portion of the shifted second nanopillar 154a may not be supported by the corresponding first nanopillar 152a, such as... Figure 3 As shown. In this case, when the degree of displacement is large, the second nanopillar 154a may tilt or collapse. In an embodiment, a support layer 156 is formed below the second metalens layer 154 to support the second nanopillar 154a. For example, on the bottom surface of the displaced second nanopillar 154a, the portion in contact with the first nanopillar 152a can be supported by the first nanopillar 152a, and the remaining portion can be supported by the support layer 156. As a result, the second nanopillar 154a can be stacked on top of the first nanopillar 152a to achieve a more stable connection between the layers of the second nanopillar 154a and the first nanopillar 152a.

[0046] The support layer 156 may include: a first support layer 156a, which includes a plurality of through-holes; and a second support layer 156b, which fills the through-holes of the first support layer 156 and covers the top surface of the first support layer 156a. The second support layer 156b may include the same material as the capping layer 154b and may be formed together with the capping layer 154b. The second support layer 156b may also be formed to cover the bottom surface of the first support layer 156a.

[0047] The support layer 156 may be formed around the upper part of the first nanopillars 152a. For example, the support layer 156 may be disposed on the air layer 152b between the first nanopillars 152a, such that the support layer 156 can contact the upper surface of the first nanopillars 152a.

[0048] Figures 4 to 14 This illustrates the formation of some implementation methods based on the disclosed technology. Figure 2 A cross-sectional view of an example method for the structure.

[0049] Reference Figure 4 A substrate layer 110 including a photoelectric conversion element can be formed, and a color filter layer 120 including a color filter formed to correspond to the photoelectric conversion element can be formed on the substrate layer 110.

[0050] Subsequently, a capping layer 130, an etch stop layer 140, a first sacrificial layer 162, a support material layer 156a', and a bottom anti-reflective coating (BARC) layer 164 are sequentially formed on the color filter layer 120. A photoresist pattern 166 can then be formed on the bottom anti-reflective coating (BARC) layer 164 to define the area where the first nanopillars are to be formed. In some implementations, the capping layer 130 may comprise a dielectric material with a refractive index lower than that of the nanostructure (nanopillar) and low absorption in the visible spectrum. The etch stop layer 140 and the support material layer 156a' may comprise ultra-low temperature oxide (ULTO) layers, and the first sacrificial layer 162 may comprise a spin-on carbon (SOC) layer containing carbon. The bottom anti-reflective coating (BARC) layer 164 may be used as an auxiliary layer in the photolithography process for forming the photoresist pattern 166. The bottom anti-reflective coating (BARC) layer 164 may comprise a silicon oxynitride (SiON) layer.

[0051] Reference Figure 5 The photoresist pattern 166 can be used as an etching mask to sequentially etch the bottom antireflective coating (BARC) layer 164, the support material layer 156a' and the first sacrificial layer 162, thereby forming a trench in the region where the first nanopillar is to be formed.

[0052] Subsequently, after the photoresist pattern 166 and the bottom antireflective coating (BARC) layer 164 are removed, a high-refractive-index material is formed to fill the trenches. Then, any excess high-refractive-index material remaining on the support material layer 156a' is removed by a planarization process to form the first nanopillar 152a.

[0053] High refractive index materials may include titanium dioxide (TiO2) and can be formed by atomic layer deposition (ALD) or spin coating processes.

[0054] Reference Figure 6 A neutral layer 168 and a directional self-assembly (DSA) material layer 170 can be sequentially formed on the support material layer 156a' and the first nanopillar 152a.

[0055] Neutral layer 168 can induce patterning of DSA material layer 170. Neutral layer 168 can be used to induce phase separation of polymer blocks forming block copolymers into block domain portions arranged alternately in cylindrical or layered shapes. Neutral layer 168 can operate as an orientation control layer to regulate the orientation of polymer blocks during phase separation processes, wherein polymer blocks rearrange to form alternating block domain portions.

[0056] The neutral layer 168 may be formed of a material having similar affinity for the various polymer block components forming the block copolymer. For example, the neutral layer 168 may comprise a random copolymer in which the different polymer components forming the block copolymer are randomly copolymerized. When polystyrene-polymethyl methacrylate block copolymer (PS-b-PMMA) is used as a self-aligned block copolymer, the neutral layer 168 may comprise a random copolymer of polystyrene and polymethyl methacrylate (PS-b-PMMA) (i.e., random PS:PMMA (PS-r-PMMA)).

[0057] DSA material layer 170 may comprise a block copolymer composed of two or more polymer blocks with different structures, covalently bonded to form a polymer. For example, DSA material layer 170 may comprise polymethyl methacrylate (PMMA) and polystyrene (PS). DSA material layer 170 may be applied using a spin-coating method to achieve a homogeneous phase mixture.

[0058] Reference Figure 7 DSA patterning can be performed on the DSA material layer 170. For example, an N2 annealing process can be performed on the DSA material layer 170.

[0059] The DSA material layer 170 can be phase-separated into a first polymer block component 170a and a second polymer block component 170b by an annealing process. When the DSA material layer 170 includes a block copolymer, the DSA material layer 170 can be phase-separated into PMMA (polymethyl methacrylate) and PS (polystyrene) by an annealing process. PMMA and PS can be self-aligned in various forms depending on the composition ratio.

[0060] Due to differences in chemical structure, the polymer block components constituting a block copolymer can have different mixing properties and different solubilities. The polymer components can be separated immiscibly while being mixed by annealing, and can be rearranged so that the polymer components can be separated from each other.

[0061] The formation of specific-shaped microstructures through the directional self-assembly of block copolymers can be influenced by the physical and / or chemical properties of each block polymer. When a block copolymer composed of two different polymers self-assembles, the self-assembled structure of the block copolymer can form various structures, such as three-dimensional (3D) cubic and double-helix structures, or two-dimensional (2D) hexagonal filled pillar structures and layered structures, depending on the volume ratio of the individual polymer blocks constituting the block copolymer, the annealing temperature for phase separation, the molecular size of the block polymers, and other factors.

[0062] Reference Figure 8 The first polymer block component 170a can be selectively removed from the DSA material layer 170, which is separated into the first polymer block component 170a and the second polymer block component 170b.

[0063] For example, a metal-containing precursor can be implanted into the DSA material layer 170 such that the metal-containing precursor can be selectively coupled (bonded) to the first polymer block component 170a. The metal in the metal-containing precursor may include aluminum (Al). The metal-containing precursor may include tetramethylammonium (TMA). For example, TMA may be selectively coupled (bonded) to PMMA.

[0064] By implanting this metal-containing precursor, the metal can permeate into the first polymer block component 170a, transforming it into a metal-containing first polymer block component. The metal-containing first polymer block component can exhibit etch selectivity relative to the second polymer block component 170b. The first polymer block component 170a can be selectively removed using this etch selectivity.

[0065] Reference Figure 9 The neutral layer 168 and the support material layer 156a' are etched using a DSA pattern including the second polymer block component 170b as an etching mask, and then the neutral layer 168 is removed, resulting in the formation of the first support layer 156a.

[0066] When the support material layer 156a' is etched, the first nanopillar 152a is not etched. The support material layer 156a' is etched only by selective etching, so that a first support layer 156a including multiple through holes can be formed to surround the upper part of the first nanopillar 152a.

[0067] In this configuration, multiple vias allow the first sacrificial layer 162 to be exposed to the outside.

[0068] Reference Figure 10 A second sacrificial layer 172, a hard mask layer 174, and a bottom anti-reflective coating (BARC) layer 176 are sequentially formed on the first support layer 156a and the first nanopillars 152a. A photoresist pattern 178 defining the region where the second nanopillars are to be formed can then be formed on the bottom anti-reflective coating (BARC) layer 176. In some implementations, the second sacrificial layer 172 may include the same material layer as the first sacrificial layer 162. For example, the second sacrificial layer 172 may include a carbon-containing SOC layer, and the hard mask layer 174 may include an ultra-low temperature oxide (ULTO) layer. The bottom anti-reflective coating (BARC) layer 176 may be used as an auxiliary layer in the photolithography process for forming the photoresist pattern 178 and may include a silicon oxynitride (SiON) layer.

[0069] The open areas of the photoresist pattern 178 (e.g., the areas where the second nanopillars are to be formed) can be positioned according to the formation location of the second nanopillars within the pixel region 100 and the CRA of the incident light. For example, as Figure 10As shown, the open area of ​​the photoresist pattern 178 is positioned such that the central axis of the open area coincides with the central axis of the first nanopillar 152a, but the scope or spirit of the disclosed technique is not limited thereto. In the edge region of the pixel region 100, the open area of ​​the photoresist pattern 178 may be positioned to be displaced relative to the first nanopillar 152a.

[0070] Reference Figure 11 Using a photoresist pattern 178 as an etching mask, a bottom antireflective coating (BARC) layer 176, a hard mask layer 174, and a second sacrificial layer 172 are sequentially etched to form trenches in the region where the second nanopillars are to be formed. The trenches can be formed such that the first nanopillars 152a are exposed.

[0071] Subsequently, after the photoresist pattern 178 and the bottom antireflective coating (BARC) layer 176 are removed, a high refractive index material is formed to fill the trench, and a planarization process is performed until the second sacrificial layer 172 is exposed so that the second nanopillar 154a can be formed on the first nanopillar 152a to be directly connected to the first nanopillar 152a.

[0072] High refractive index materials may include titanium dioxide (TiO2) and may be formed via atomic layer deposition (ALD) or spin coating processes.

[0073] Reference Figure 12 The first sacrificial layer 162 and the second sacrificial layer 172 are removed by plasma process, so that an air layer 152b can be formed in the space between the first nanopillars 152a and an air layer 154c can be formed in the space between the second nanopillars 154a.

[0074] In some implementations, a gas including at least one of oxygen, nitrogen, or hydrogen (e.g., O2, N2, H2, CO, CO2, or CH4) can be used to perform the plasma process.

[0075] For example, if an O2 plasma process is performed, oxygen radicals (O*) can bind to the carbon in the first and second sacrificial layers (162, 172). The binding of oxygen radicals (O*) to the carbon in the first and second sacrificial layers (162, 172) results in the formation of CO or CO2. Consequently, the first sacrificial layer 162 and the second sacrificial layer 172 can be removed. In some implementations, the first sacrificial layer 162 formed between the first nanopillars 152a is exposed to the outside through multiple vias formed in the first support layer 156a, allowing the first sacrificial layer 162 to couple to oxygen radicals and thus be easily removed.

[0076] Reference Figure 13The second support layer 156b and the capping layer 154b can be formed by depositing an insulating material to fill the through-holes of the first support layer 156a. For example, the second support layer 156b can be formed to cover the top surface of the first support layer 156a while filling the through-holes of the first support layer 156a, and the capping layer 154b can be formed to cover the top and side surfaces of the second nanopillar 154a.

[0077] Each of the second support layer 156b and the capping layer 154b may include a low-temperature oxide (LTO) layer. Figure 13 For ease of description, the second support layer 156b and the capping layer 154b are shown separately, but the second support layer 156b and the capping layer 154b can be formed together by the same deposition process.

[0078] although Figure 13 This example only shows the second support layer 156b covering the top surface of the first support layer 156a while filling the through-holes of the first support layer 156a, but other implementations are possible. For example, the second support layer 156b' could be formed to cover the bottom surface of the first support layer 156a, the side surfaces of the nanopillars 152a, and the top surface of the etch stop layer 140, as shown below. Figure 14 As shown.

[0079] Although the above embodiment provides an example of a nanostructure in which the metalens layer 150 comprises two stacked nanopillars (152a, 154a) for ease of description, other implementations are possible. For example, three or more nanopillars may be stacked.

[0080] It is evident from the above description that the implementation of the disclosed technology can reduce or minimize the degradation of quantum efficiency (QE) relative to oblique incident light incident on an image sensing device employing metalenses.

[0081] The implementation of the disclosed technology can provide various effects that can be directly or indirectly understood through the aforementioned patent documents.

[0082] Although several exemplary embodiments have been described, it should be understood that various modifications or enhancements to the disclosed embodiments and other embodiments may be conceived based on the description and / or illustrations in this patent document.

[0083] Cross-reference to related applications

[0084] This patent document claims priority and benefit to Korean Patent Application No. 10-2024-0161395, filed on November 13, 2024, the entirety of which is incorporated by reference as part of the disclosure of this patent document.

Claims

1. An image sensing device, the image sensing device comprising: A semiconductor substrate, the semiconductor substrate including a photoelectric conversion element that generates photocharge by converting incident light; as well as A metalens layer is disposed above the semiconductor substrate, and it separates the incident light into light components of different colors based on wavelength and focuses the separated light components onto the corresponding photoelectric conversion element. The meta-lens layer includes: A first meta-lens layer, the first meta-lens layer comprising a first nanostructure and a first air layer disposed between the first nanostructure; A second metalens layer, comprising second nanostructures and a second air layer disposed between the second nanostructures, wherein at least a portion of each of the second nanostructures is disposed on a corresponding first nanostructure within the first nanostructure; and A support layer is disposed above the first air layer in the space between adjacent first nanostructures in the first nanostructure.

2. The image sensing device according to claim 1, wherein, The second nanostructure is disposed on the first nanostructure such that the bottom surface of the second nanostructure is in contact with the top surface of the first nanostructure.

3. The image sensing device according to claim 1, wherein, The second nanostructure is laterally shifted relative to the first nanostructure, such that the central axis of the second nanostructure is shifted relative to the central axis of the first nanostructure in accordance with the principal ray angle CRA of the incident light.

4. The image sensing device according to claim 3, wherein, A portion of the bottom surface of each of the second nanostructures is in contact with a corresponding portion of the first nanostructure in the first nanostructure, and the remaining portion of the bottom surface of each of the second nanostructures is in contact with the support layer.

5. The image sensing device according to claim 1, wherein, The support layer includes: A first support layer, the first support layer being configured with a plurality of through-holes formed therein; and A second support layer fills the plurality of through holes.

6. The image sensing device according to claim 5, wherein, The second support layer covers the top surface of the first support layer.

7. The image sensing device according to claim 5, wherein, The second support layer covers the top and bottom surfaces of the first support layer.

8. The image sensing device according to claim 5, wherein, The first support layer includes an ultra-low temperature oxide (ULTO) layer; and The second support layer includes a low-temperature oxide (LTO) layer.

9. The image sensing device according to claim 1, wherein, The support layer surrounds the upper part of the first nanostructure, thereby exposing the top surface of the first nanostructure.

10. The image sensing device according to claim 1, wherein, The second meta-lens layer also includes: A capping layer that covers the top and side surfaces of the second nanostructure.

11. The image sensing device according to claim 10, wherein, The capping layer extends into the region below the second air layer.

12. The image sensing device according to claim 1, further comprising: A color filter layer is disposed between the semiconductor substrate and the metalens layer.

13. The image sensing device according to claim 12, further comprising: A cover layer disposed above the color filter layer; as well as An etch stop layer is disposed between the capping layer and the first nanostructure.

14. An image sensing device, the image sensing device comprising: A semiconductor substrate, the semiconductor substrate including a photoelectric conversion element that generates photocharge by converting incident light; A plurality of first nanostructures are disposed above the semiconductor substrate; A first air layer is disposed between adjacent first nanostructures in the plurality of first nanostructures; A support layer is disposed between the adjacent first nanostructures, such that at least a portion of the adjacent first nanostructures is exposed; A plurality of second nanostructures are disposed above the first nanostructure; as well as A second air layer is disposed between the second nanostructures.

15. The image sensing device according to claim 14, wherein, The second nanostructure is laterally shifted relative to the first nanostructure, such that the central axis of the second nanostructure is shifted relative to the central axis of the first nanostructure in accordance with the principal ray angle CRA of the incident light.

16. The image sensing device according to claim 15, wherein, A portion of the bottom surface of each of the second nanostructures is in contact with a corresponding portion of the first nanostructure in the first nanostructure, and the remaining portion of the bottom surface of each of the second nanostructures is in contact with the support layer.

17. The image sensing device according to claim 14, wherein, The support layer includes: A first support layer, the first support layer being configured with a plurality of through-holes formed therein; and A second support layer fills the plurality of through holes.

18. The image sensing device according to claim 17, wherein, The second support layer covers the top surface of the first support layer.

19. The image sensing device according to claim 17, wherein, The second support layer covers the top and bottom surfaces of the first support layer.

20. The image sensing device according to claim 14, further comprising: A capping layer that covers the top and side surfaces of the second nanostructure.

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