Image sensing device and method of manufacturing image sensing device

Abstract

The present application relates to an image sensing device and a method of manufacturing an image sensing device. The image sensing device includes a semiconductor substrate including a pixel region and a peripheral region located outside the pixel region; a first superlens layer disposed over the semiconductor substrate in the pixel region and configured to include first nanopillars and first air layers disposed between the first nanopillars; a second superlens layer disposed over the first superlens layer and configured to include second nanopillars and second air layers disposed between the second nanopillars; a lens support layer disposed between the first superlens layer and the second superlens layer and configured to extend from the pixel region to the peripheral region; and a peripheral support layer disposed under the lens support layer in the peripheral region and configured to support the lens support layer.

Description

Technical Field

[0001] The technologies and implementations disclosed in this patent document generally relate to image sensing devices comprising one or more superlenses. Background Technology

[0002] Super-optical devices refer to the field of optical technology that achieves new optical properties in controlling or manipulating light, properties that cannot be easily achieved using existing materials or conventional optical devices (such as optical lenses with curved surfaces) by using nanostructures with a scale smaller than the wavelength of light.

[0003] An image sensor is a device that includes image sensing pixels that convert optical images into electrical pixel signals. In some implementations of such an image sensor, each pixel may include a microlens for receiving incident light and a color filter for optically filtering light of a desired wavelength or spectral range for sensing while rejecting other wavelength components. As pixels are increasingly manufactured in ultra-fine sizes to meet the demands of high-resolution cameras in certain applications, the size of the pixel's microlens and color filter decreases, and this reduction in size results in a decrease in the optical aperture used to receive light, leading to a reduction in luminous efficiency in the image sensor.

[0004] As an alternative to the limitations of the aforementioned conventional technologies, research is being actively conducted on superlenses suitable for super-optics-based image sensors. Summary of the Invention

[0005] Various embodiments of the disclosed technology relate to an image sensing device that can improve the degradation of quantum efficiency (QE) caused by oblique incident light and enhance the structural stability of a superlens.

[0006] According to an embodiment of the disclosed technology, an image sensing device may include: a semiconductor substrate, the semiconductor substrate including a pixel region and a peripheral region located outside the pixel region; a first superlens layer, the first superlens layer being disposed above the semiconductor substrate in the pixel region, and including first nanopillars and a first air layer disposed between the first nanopillars; a second superlens layer, the second superlens layer being disposed above the first superlens layer, and including second nanopillars and a second air layer disposed between the second nanopillars; a lens support layer, the lens support layer being disposed between the first superlens layer and the second superlens layer, and extending from the pixel region to the peripheral region; and a peripheral support layer, the peripheral support layer being disposed below the lens support layer in the peripheral region, and supporting the lens support layer.

[0007] According to another embodiment of the disclosed technology, a method of manufacturing an image sensing device may include the following steps: forming a first sacrificial layer over a semiconductor substrate in a pixel region and a peripheral region located outside the pixel region; forming a first nanopillar within the first sacrificial layer in the pixel region; forming a first support layer on the first sacrificial layer and the first nanopillar in the pixel region and the peripheral region; forming a via in the first support layer to expose a portion of the first sacrificial layer in the pixel region; removing the portion of the first sacrificial layer in the pixel region through the via while retaining a portion of the first sacrificial layer in the peripheral region; forming a second support layer overlapping the first support layer and filling the via of the first support layer; and forming a second nanopillar on the second support layer.

[0008] The above and other features, implementation methods and examples for implementing the disclosed technology are described in more detail below with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a plan view illustrating an example of a planar structure of an image sensing device according to an embodiment of the disclosed technology.

[0010] Figure 2 This describes the implementation of the technology according to the disclosed techniques. Figure 1 A cross-sectional view of an example structure vertically intercepted by line X-X'.

[0011] Figures 3 to 15 This illustrates an embodiment of the disclosed technology for forming Figure 2 A cross-sectional view of an example method for the structure. Detailed Implementation

[0012] This patent document provides embodiments and examples of image sensing devices comprising one or more superlenses, 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 embodiments of the disclosed technology present examples of image sensing devices capable of improving the degradation of quantum efficiency (QE) affected by oblique incident light and enhancing the structural stability of the superlenses. Recognizing the aforementioned problems, the disclosed technology can be implemented to provide various features in the image sensing device that can improve the degradation of quantum efficiency (QE) relative to oblique incident light in the image sensing device employing superlenses, and additionally enhance the structural stability of the superlenses.

[0013] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings. Where possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. In the following description, detailed descriptions of relevant known configurations or functions incorporated herein will be omitted to avoid obscuring the subject matter.

[0014] 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 can be implemented through various modifications, equivalents, and / or substitutions of the embodiments. Embodiments of the disclosed technology can provide various effects that can be directly or indirectly identified by the disclosed technology.

[0015] Figure 1 This is a plan view illustrating an example of a planar structure of an image sensing device according to an embodiment of the disclosed technology.

[0016] refer to Figure 1 The image sensing device 1 may include a pixel region 100 and a peripheral region 200 outside the pixel region 100.

[0017] Pixel region 100 may be located at the center of image sensing device 1 and may include a plurality of unit pixels PX supported by a semiconductor substrate and arranged in a two-dimensional (2D) matrix structure (e.g., continuously arranged in a first direction and a second direction perpendicular to the first direction). Each of the plurality of unit pixels PX may include a photoelectric conversion element (e.g., a photodiode PD) that converts incident light into an electrical signal within the semiconductor substrate. Additionally, the plurality of unit pixels PX may include pixel transistors for reading out the electrical signals generated by the photoelectric conversion elements.

[0018] Pixel region 100 may include a superlens layer formed above a semiconductor substrate to separate incident light by color. For example, the superlens layer may include a three-dimensional (3D) nanostructure (e.g., nanopillar) with a scale smaller than the wavelength of light.

[0019] In a superlens, air layers can be formed between adjacent nanopillars, and nanopillars can be formed in a multilayer structure. Support layers can be formed between the stacked nanopillars to support the upper nanopillars. The support layers can be formed to extend from pixel region 100 to the peripheral region. In some implementations, nanopillars may be formed only in pixel region 100 and may not be formed in the peripheral region 200. The detailed structure of the superlens layer will be described in more detail later with reference to the accompanying drawings.

[0020] The peripheral region 200 may refer to a region located outside the pixel region 100. In some implementations, the peripheral region 200 may be formed to surround the pixel region 100. The peripheral region 200 may include a light-blocking layer to prevent incident light from reaching the semiconductor substrate. The peripheral region 200 may include a pad region in which conductive pads for providing electrical connections between the image sensing device and external devices are formed.

[0021] Figure 2 This describes the implementation of the technology according to the disclosed techniques. Figure 1 A cross-sectional view of an example structure vertically intercepted by line X-X'.

[0022] refer to Figure 2 The image sensing device 1 may include a substrate 110, a color filter layer 120 above the substrate 110, an outer coating layer 130 above the color filter layer 120, an etch stop layer 140 above the outer coating layer 130, a super lens layer 150, and a peripheral support layer 160.

[0023] The substrate 110 may include a semiconductor substrate having a first surface and a second surface facing or opposite to the first surface. The first surface is the surface on which light is incident on and received by the image sensing device 1, and a color filter layer 120, an outer coating layer 130, an etch stop layer 140, and a superlens layer 150 may be formed above the first surface of the substrate 110. The semiconductor substrate 110 may be in a single-crystal state and may include silicon-containing materials. The semiconductor substrate 110 may include a pixel region 100 and a peripheral region located outside the pixel region 100. The semiconductor substrate 110 of the pixel region 100 may include a photoelectric conversion element 112, which can perform conversion on the incident light received through the first surface to form photocharge.

[0024] Color filter layer 120 may include a plurality of color filters arranged to correspond to a unit pixel, such that each color filter filters incident light to each unit pixel to allow reception and detection of light of a specific color wavelength while rejecting light of other wavelengths. The color filters may be arranged in a Bayer pattern or another suitable pattern for capturing color information of the incident light. Color filter layer 120 may include a grid structure disposed between the color filters to prevent crosstalk between them.

[0025] The outer coating 130 can be disposed above the color filter layer 120 and can be used as a planarization layer to remove the step difference between the grating structure and the color filter. The outer coating 130 can include a material that is transparent to visible light, such as a dielectric material (e.g., SiO2, siloxane-based spin-coated glass (SOG), etc.) having a lower refractive index and lower absorption in the visible spectrum than the nanostructure (nanopillars) of the superlens layer 150.

[0026] The outer coating 130 may have a material and thickness that, together with the etch stop layer 140, can achieve a target refractive index. The target refractive index may be the theoretical refractive index that should be assigned to the effective medium disposed between the two materials, so that undesirable light reflections occurring at the interface between materials with different refractive indices can be minimized.

[0027] An etch stop layer 140 may be formed over the outer coating 130 and may serve as an etch stop layer to protect the outer coating 130 during the etching process for forming the first nanopillar 152a. The etch stop layer 140 may include an ultra-low temperature oxide (ULTO) layer.

[0028] The superlens layer 150 can converge (focus) incident light onto the photoelectric conversion element 112 supported by the substrate 110. For example, the superlens layer 150 can separate the incident light into beams of different colors corresponding to different wavelengths of color filters arranged in a Bayer pattern, and can focus the separated beams 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 superlens layer 150 can use this characteristic to separate the colors of the incident light from each other. Depending on the refractive index distribution of the superlens layer 150 and the shape of the nanopillars, the transmission direction of the separated beams can be adjusted to correspond to each wavelength.

[0029] exist Figure 2 In the example, the superlens layer 150 may include a first superlens layer 152, a second superlens layer 154, and a lens support layer 156.

[0030] The first superlens layer 152 and the second superlens layer 154 may be located in the pixel region 100. The first superlens layer 152 may include a first nanopillar 152a and an air layer 152b in the space between the first nanopillars 152a. The second superlens layer 154 may include a second nanopillar 154a and an air layer 154b in the space between the second nanopillars 154a.

[0031] Each of the first nanopillars 152a and each of the second nanopillars 154a can be formed as a column with a diameter smaller than the wavelength of the incident light. For example, the nanopillars 152a and 154a can be formed in various columnar shapes, such as cylindrical, polygonal, and elliptical columnar shapes. A first air layer 152b can be formed between the first nanopillars 152a in the first superlens layer 152, and a second air layer 154b can be formed between the second nanopillars 154a in the second superlens layer 154.

[0032] In some implementations, the first nanopillar 152a and the second nanopillar 154a can be formed of the same material. For example, nanopillars 152a and 154a may include a high refractive index material (e.g., TiO2). The first nanopillar 152a and the second nanopillar 154a can be stacked one-to-one with each other based on a lens support layer 156 inserted between them, thereby forming a nanostructure of the superlens layer 150. The first nanopillar 152a and the second nanopillar 154a can be configured to partially overlap each other in the vertical direction.

[0033] The second nanopillar 154a can be shifted from the first nanopillar 152a in response to the principal ray angle (CRA) of the incident light. For example, the second nanopillar 154a located at the center of the 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 the second nanopillar 154a located in the edge region of the pixel region 100 can be positioned such that the central axis of the second nanopillar 154a can be shifted from the central axis of the first nanopillar 152a in response to the principal ray angle (CRA) in the corresponding region.

[0034] The stacked nanopillars 152a and 154a can have the same shape and size. For example, the first nanopillar 152a and the second nanopillar 154a stacked corresponding to each other can be formed as pillars with the same diameter and height. Alternatively, the first nanopillar 152a and the second nanopillar 154a stacked corresponding to each other can have different shapes and sizes.

[0035] The stacked nanopillars 152a and 154a can be arranged in a pattern that separates incident light by color and allows the separated light to be focused onto 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 and 154a can be arranged to have a refractive index distribution capable of forming a phase profile that separates the incident light into different wavelengths of different colors (e.g., red, green, and blue) and allows the separated beams of different colors to be focused onto unit pixels of the corresponding colors. The aforementioned refractive index distribution can be formed by the shape and arrangement of the nanopillars 152a and 154a, and can be determined by the refractive index difference between the nanopillars 152a and 154a and the material surrounding the nanopillars 152a and 154a.

[0036] according to Figure 2 In this embodiment, the superlens layer 150 can be formed with a structure in which multiple nanopillars 152a and 154a are stacked, and the upper second nanopillar 154a can be shifted to correspond to CRA, thereby improving the degradation of quantum efficiency (QE) affected by oblique incident light. Figure 2In this embodiment, when the nanopillars 152a and 154a are formed in a stacked structure and the upper second nanopillar 154a is shifted to correspond to CRA, the degradation of quantum efficiency (QE) caused by oblique incident light can be more effectively improved as the height of the nanopillars 152a and 154a decreases. The superlens layer 150 according to this embodiment allows air layers 152b and 154b to be formed between the nanopillars 152a and 154a, such that the refractive index difference between the nanostructure and the surrounding material is greater than the refractive index difference in a design where a material with a higher refractive index than the air layer is formed, thereby relatively reducing the height of the nanopillars 152a and 154a.

[0037] In some implementations, nanopillars 152a and 154a may be formed in pixel region 100, but may not be formed in peripheral region 200. For example, nanopillars 152a and 154a may not be formed anywhere in peripheral region 200, or may not be formed in a specific area (e.g., pad area) within peripheral region 200.

[0038] A lens support layer 156 may be disposed above the first nanopillar 152a and the peripheral support layer 160. For example, the lens support layer 156 may be formed to extend from the pixel region 100 to the peripheral region 200. The lens support layer 156 formed in the pixel region 100 may be disposed between the first nanopillar 152a and the second nanopillar 154a, and may be supported by the first nanopillar 152a while simultaneously supporting the second nanopillar 154a. Furthermore, the lens support layer 156 formed in the peripheral region 200 may be disposed above the peripheral support layer 160, and may be supported by the peripheral support layer 160.

[0039] With the first nanopillar 152a and the second nanopillar 154a formed in a stacked structure and the upper second nanopillar 154a shifted to correspond to CRA, without the lens support layer 156, some of the bottom surface of the second nanopillar 154a is supported by the first nanopillar 152a, but the remaining portion of the bottom surface is not supported by the first nanopillar 152a. In this design without the support layer, the second nanopillar 154a may undesirably tilt or collapse when the shift is large.

[0040] In this embodiment, since the lens support layer 156 is formed below the second nanopillar 154a, the lens support layer 156 can support the second nanopillar 154a. As a result, the second nanopillar 154a can be more stably stacked above the first nanopillar 152a.

[0041] When the first nanopillars 152a and the second nanopillars 154a are formed up to the peripheral region 200, it is difficult to remove the nanopillars 152a and 154a during the etching process used to form pads in the peripheral region 200. Therefore, according to this embodiment, the first nanopillars 152a and the second nanopillars 154a may not be formed in the peripheral region 200. For example, the nanopillars 152a and 154a may not be formed anywhere in the peripheral region 200, or they may not be formed in a specific area of ​​the peripheral region 200 (e.g., the pad area).

[0042] However, if the air layer 152b is formed below the lens support layer 156 in the same manner as in the pixel region 100, instead of forming nanopillars 152a and 154a in the peripheral region 200, the lens support layer 156 may collapse. In this case, the nanopillars 152a and 154a formed in the pixel region 100 may also be affected. In this embodiment, in order to prevent the lens support layer 156 from collapsing due to the absence of nanopillars 152a and 154a in the peripheral region 200, the peripheral support layer 160 may be formed above the entire peripheral region 200, without forming the air layer 152b below the lens support layer 156 in the peripheral region 200.

[0043] The lens support layer 156 may include: a first support layer 156a, which includes a plurality of through-holes; and a second support layer 156b, which covers the top and bottom surfaces of the first support layer 156a and fills the through-holes of the first support layer 156a. The through-holes of the first support layer 156a may be formed only in the pixel region and may not be formed in the peripheral region 200. The second support layer 156b may be formed to extend to the side surface of the first nanopillar 152a to cover the side surface of the first nanopillar 152a. The second support layer 156b may be formed to extend to the top surface of the etch stop layer 140.

[0044] The first support layer 156a and the second support layer 156b can be formed of the same material. For example, the first support layer 156a and the second support layer 156b may comprise a low-temperature oxide (LTO) layer or an ultra-low-temperature oxide (ULTO) layer. Alternatively, the first support layer 156a and the second support layer 156b may be formed of different materials.

[0045] The peripheral support layer 160 can be formed in the peripheral region 200 where the first superlens layer 152 is not formed, and thus can support the lens support layer 156. The peripheral support layer 160 can be configured to cover the entire peripheral region 200. The peripheral support layer 160 can include the same material as the outer coating layer 130. For example, the peripheral support layer 160 can include a dielectric material having a lower refractive index and lower absorption rate in the visible spectrum than the nanopillars 152a and 154a.

[0046] Figures 3 to 15 This illustrates an embodiment of the disclosed technology for forming Figure 2 A cross-sectional view of an example method for the structure.

[0047] Reference Figure 3 A semiconductor substrate 110 including a photoelectric conversion element 112 can be formed, and a color filter layer 120 including a color filter formed corresponding to the photoelectric conversion element 112 can be formed above the semiconductor substrate 110.

[0048] Subsequently, an outer coating layer 130, an etch stop layer 140, a first sacrificial layer 172, a hard mask layer 156a', and a bottom anti-reflective coating (BARC) layer 174 are sequentially formed over the color filter layer 120 in the pixel region 100 and the peripheral region 200. Then, a mask pattern 176 defining the region where the first nanopillars are to be formed can be formed over the bottom anti-reflective coating (BARC) layer 174.

[0049] The outer coating 130 may comprise a dielectric material having not only a lower refractive index than nanopillars but also a low absorption rate in the visible spectrum. The etch stop layer 140 and the hard mask layer 156a' may comprise ultra-low temperature oxide (ULTO) layers, and the first sacrificial layer 172 may comprise the same material as the outer coating 130. The mask pattern 176 may comprise a photoresist pattern. The bottom anti-reflective coating (BARC) layer 174 may be used as an auxiliary layer in the photolithography process for forming the photoresist pattern 176. The bottom anti-reflective coating (BARC) layer 174 may comprise a silicon oxynitride (SiON) layer.

[0050] refer to Figure 4 By using mask pattern 176 as an etching mask, the BARC layer 174, hard mask layer 156a' and first sacrificial layer 172 are etched away sequentially, and then the mask pattern 176 and BARC layer 174 are removed, thereby forming a trench in which the first nanopillar is to be formed in the pixel region 100.

[0051] Each groove can be formed into a column shape. For example, grooves can be formed into various column shapes, such as cylindrical shapes, polygonal column shapes, elliptical column shapes, etc.

[0052] refer to Figure 5 A high refractive index material 152a' can be formed in the pixel region 100 and the peripheral region 200, such that the trench is filled with the high refractive index material 152a'. The high refractive index material 152a' may include titanium dioxide (TiO2) and can be formed by atomic layer deposition (ALD) or spin coating processes.

[0053] refer to Figure 6The first nanopillar 152a can be formed by removing the high-refractive-index material 152a' and the hard mask layer 156a', thereby exposing the first sacrificial layer 172. For example, the high-refractive-index material 152a' and the hard mask layer 156a' can be removed by a planarization process such as chemical mechanical polishing (CMP).

[0054] Reference Figure 7 A support material layer 156a'' can be formed over the first nanopillar 152a and the first sacrificial layer 172 in the pixel region 100 and the peripheral region 200. The support material layer 156a'' may include an ultra-low temperature oxide (ULTO) layer.

[0055] Subsequently, a mask pattern 178 covering the peripheral region 200 can be formed over the support material layer 156a''. The mask pattern 178 can extend to cover the portion of the first nanopillar 152a located at the outermost part of the pixel region 100, while also covering the peripheral region 200. The mask pattern 178 may include a photoresist pattern.

[0056] refer to Figure 8 The neutral layer 180 of the polymer material and the directional self-assembly (DSA) material layer 182 of the polymer material can be sequentially formed above the support material layer 156a'' and the mask pattern 178.

[0057] The neutral layer 180 can be designed to induce patterning of the DSA material layer 182. Specifically, the neutral layer 180 can be used to induce phase separation of the polymer blocks constituting the block copolymer in the DSA material layer 182 into block domain portions, which are alternately repeated in cylindrical or layered shapes. The neutral layer 180 can operate as an orientation control layer that controls the orientation of the polymer blocks during the phase separation process in which the polymer blocks are rearranged to form the block domain portions, thereby causing the block domain portions to repeat alternately.

[0058] The neutral layer 180 may be formed of a material having a similar affinity for each of the polymer block components constituting the block copolymer. For example, the neutral layer 180 may include a random copolymer in which the different polymer components constituting 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 180 may include a random copolymer of polystyrene and polymethyl methacrylate (PS-b-PMMA) (i.e., random PS:PMMA (PS-r-PMMA)).

[0059] DSA material layer 182 may include block copolymers, wherein two or more polymer blocks having different structures are covalently bonded to form a polymer. For example, DSA material layer 182 may include polymethyl methacrylate (PMMA) and polystyrene (PS). DSA material layer 182 may be coated using a spin-coating method in a homogeneous phase-mixed state.

[0060] Subsequently, DSA patterning can be performed on the DSA material layer 182. For example, an N2 annealing process can be performed on the DSA material layer 182.

[0061] DSA material layer 182 can be phase-separated into a first polymer block component 182a and a second polymer block component 182b by an annealing process. When DSA material layer 182 comprises a block copolymer, DSA material layer 182 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.

[0062] 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 mixed by annealing without forced separation and can be rearranged to allow for separation of the polymer components.

[0063] The formation of microstructures with specific shapes through the directional self-assembly of block copolymers can be influenced by the physical and / or chemical properties of each block polymer. When block copolymers composed of two different polymers self-assemble, the self-assembled structures of the block copolymers can form in a variety of 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 each polymer block constituting the block copolymer, the annealing temperature for phase separation, the size of the block polymer molecules, and other factors.

[0064] although Figure 8 The diagram shows a DSA material layer 182 formed in the peripheral region 200 of the mask pattern 178. However, other embodiments are possible, and it should be noted that the mask pattern 178 is formed with a large thickness, such that the DSA material layer 182 can be formed only in the pixel regions 100 where the mask pattern 178 is not formed. Alternatively, the DSA material layer 182 can be formed with a very small thickness above the mask pattern 178, thereby allowing DSA patterning to be performed improperly. Therefore, Figure 8 The DSA material layer 182 formed over the mask pattern 178 is shown, but Figure 8 The phase separation appearance of DSA material layer 182 is not shown.

[0065] refer to Figure 9The first polymer block component 182a can be selectively removed from the DSA material layer 182, which is separated into the first polymer block component 182a and the second polymer block component 182b.

[0066] For example, a metal-containing precursor can be implanted into the DSA material layer 182, such that the metal-containing precursor can be selectively coupled (bonded) to the first polymer block component 182a. The metal in the metal-containing precursor may include aluminum (Al). The metal-containing precursor may include tetramethylammonium (TMA). For example, TMA can be selectively coupled (bonded) to PMMA.

[0067] By implanting this metal-containing precursor, the metal can permeate into the first polymer block component 182a, thereby modifying the first polymer block component 182a into a metal-containing first polymer block component. The metal-containing first polymer component can have etch selectivity relative to the second polymer block component 182b. Etching selectivity can be used to selectively remove the first polymer block component 182a.

[0068] refer to Figure 10 The neutral layer 180 and the support material layer 156a'' of the pixel region 100 are etched using a DSA pattern including the second polymer block component 182b as an etching mask, thereby forming vias in the support material layer 156a''. When etching the support material layer 156a'', etching selectivity can be used to etch the first nanopillar 152a without using etching.

[0069] In the peripheral region 200, as described above, DSA patterning is performed abnormally, such that no DSA pattern is formed, or even if a DSA pattern is formed, the support material layer 156a'' is not etched due to the mask pattern 178 formed beneath it. In other words, the support material layer 156a'' can be selectively etched only in the pixel region 100 by the mask pattern 178, thereby forming a via.

[0070] Subsequently, the neutral layer 180 and the mask pattern 178 are removed, allowing the formation of a first support layer 156a with vias formed only in the pixel region 100. Therefore, the first sacrificial layer 172 can be exposed to the outside only through the vias in the pixel region 100.

[0071] Then, an etching process can be performed using the first support layer 156a, in which vias are formed, as an etching mask to selectively remove the first sacrificial layer 172. By etching, the first sacrificial layer 172 in the pixel region 100 is removed while the first sacrificial layer 172 in the peripheral region 200 is retained, thereby forming an air layer 152b in the space between the first nanopillars 152a and forming a peripheral support layer 160 in the peripheral region 200. At this time, an O2 plasma process can be used for the etching process.

[0072] In pixel region 100, the first sacrificial layer 172 can be removed by O2 plasma penetrating through a via into the first sacrificial layer 172. However, in the peripheral region 200 where no via is formed, the O2 plasma does not penetrate into the first sacrificial layer 172, so the first sacrificial layer 172 is not removed and is retained, resulting in the formation of peripheral support layer 160.

[0073] Reference Figure 11 Insulating material can be deposited to fill the through-holes in the first support layer 156a, thereby forming the second support layer 156b.

[0074] The second support layer 156b can be formed to cover the top and bottom surfaces of the first support layer 156a, while filling the through-holes of the first support layer 156a. Furthermore, the second support layer 156b can be formed to cover the side surfaces of the first nanopillar 152a.

[0075] The second support layer 156b may include the same ultra-low temperature oxide (ULTO) layer as the first support layer 156a. Alternatively, in some implementations, the second support layer 156b may be formed of a different material layer than the first support layer 156a.

[0076] refer to Figure 12 A second sacrificial layer 184, a hard mask layer 186, and a bottom anti-reflective coating (BARC) layer 188 are sequentially formed above the second support layer 156b. A photoresist pattern 190 defining the region where the second nanopillars are to be formed can then be formed above the bottom anti-reflective coating (BARC) layer 188. The second sacrificial layer 184 may include a carbon-containing SOC (spin-coated carbon) layer, and the hard mask layer 186 may include an ultra-low temperature oxide (ULTO) layer. The bottom anti-reflective coating (BARC) layer 188 can be used as an auxiliary layer in the photolithography process for forming the photoresist pattern 190. The bottom anti-reflective coating (BARC) layer 188 may include a silicon oxynitride (SiON) layer.

[0077] The opening region of the photoresist pattern 190 can be arranged to correspond to the principal ray angle (CRA) of the incident light. For example, the opening region of the photoresist pattern 190 can be positioned such that the central axis of the opening region of the photoresist pattern 190 coincides with the first nanopillar 152a in the central region of the pixel region 100, and is shifted from the first nanopillar 152a in the edge region of the pixel region 100.

[0078] refer to Figure 13 Using a photoresist pattern 190 as an etching mask, the bottom anti-reflective coating (BARC) layer 188, the hard mask layer 186, and the second sacrificial layer 184 are etched sequentially. Then, the photoresist pattern 190 and the bottom anti-reflective coating (BARC) layer 188 are removed, thereby forming a trench in the pixel region 100 for forming the second nanopillar.

[0079] Grooves can be formed to expose the lens support layer 156 to the outside. Each of the grooves can be formed in a columnar shape. For example, the grooves can be formed in various columnar shapes, such as cylindrical shapes, polygonal columnar shapes, elliptical columnar shapes, etc.

[0080] refer to Figure 14 A high-refractive-index material 154a' can be formed in the pixel region 100 and the peripheral region 200, such that the trench is filled with the high-refractive-index material 154a'. The high-refractive-index material 154a' may include titanium dioxide (TiO2) and can be formed by atomic layer deposition (ALD) or spin coating processes.

[0081] refer to Figure 15 The second nanopillar 154a can be formed by removing the high-refractive-index material 154a' and the hard mask layer 186, thereby exposing the second sacrificial layer 184. For example, the high-refractive-index material 154a' and the hard mask layer 186 can be removed by a planarization process such as chemical mechanical polishing (CMP).

[0082] Subsequently, the second sacrificial layer 184 exposed to the outside can be etched and removed, thereby forming an air layer 154b in the space between the second nanopillars 154a. At this time, the etching process can use an O2 plasma process.

[0083] The air layer 154b can be formed not only in the pixel region 100, but also in the peripheral region 200.

[0084] Although the above embodiments have been disclosed for ease of description, the superlens layer 150 includes a nanostructure in which two nanopillars 152a and 154a are stacked, other embodiments are also possible, and for example, three or more nanopillars may be stacked.

[0085] As is evident from the above description, the image sensing device and its manufacturing method according to the embodiments of the disclosed technology can improve the degradation of quantum efficiency (QE) relative to the oblique incident light of the image sensing device using a superlens.

[0086] The image sensing device and its manufacturing method according to the disclosed technology can improve the structural stability of the superlens.

[0087] The implementation of the disclosed technology can provide various effects that can be directly or indirectly identified through the aforementioned patent documents.

[0088] Although several illustrative embodiments have been described, it should be understood that various modifications or enhancements to the disclosed embodiments and other embodiments can be designed based on what is described and / or shown in this patent document.

[0089] Cross-reference to related applications

[0090] This patent document claims priority and benefit to Korean Patent Application No. 10-2025-0053232, filed on April 23, 2025, which is incorporated herein by reference in its entirety 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 pixel region and a peripheral region located outside the pixel region; A first superlens layer is disposed above the semiconductor substrate in the pixel region, and includes first nanopillars and a first air layer disposed between the first nanopillars; A second superlens layer is disposed above the first superlens layer and includes second nanopillars and a second air layer disposed between the second nanopillars; A lens support layer is disposed between the first superlens layer and the second superlens layer, and extends from the pixel region to the peripheral region; as well as An outer support layer is disposed in the outer region below the lens support layer and supports the lens support layer.

2. The image sensing device according to claim 1, wherein, The outer support layer is configured to cover the entire outer area.

3. The image sensing device according to claim 1, wherein, The outer support layer comprises a dielectric material having a refractive index lower than that of the first nanopillar and the second nanopillar.

4. The image sensing device according to claim 1, wherein, The lens support layer includes: A first support layer, the first support layer including a plurality of through holes; and A second support layer is provided, which fills the plurality of through-holes in the first support layer.

5. The image sensing device according to claim 4, wherein, The second support layer covers the top and bottom surfaces of the first support layer.

6. The image sensing device according to claim 5, wherein, The top surface of the first nanopillar contacts the first support layer; and The bottom surface of the second nanopillar contacts the second support layer.

7. The image sensing device according to claim 4, wherein, The second support layer extends to the side surface of the first nanopillar.

8. The image sensing device according to claim 4, wherein, The first support layer and the second support layer comprise the same material layer.

9. The image sensing device according to claim 4, wherein, Each of the first support layer and the second support layer includes a cryogenic oxide (ULTO) layer.

10. The image sensing device according to claim 1, wherein, The first nanopillar and the second nanopillar are positioned such that at least a portion of the first nanopillar and at least a portion of the second nanopillar overlap each other in the vertical direction.

11. The image sensing device according to claim 10, wherein, The second nanopillar is arranged to shift from the first nanopillar in response to the principal ray angle CRA of the incident light.

12. The image sensing device according to claim 1, further comprising: A color filter layer is disposed between the semiconductor substrate and the first superlens layer; as well as An outer coating layer is disposed between the color filter layer and the first superlens layer.

13. A method for manufacturing an image sensing device, the method comprising the following steps: A first sacrificial layer is formed over the semiconductor substrate in the pixel region and in the peripheral region outside the pixel region; A first nanopillar is formed within the first sacrificial layer in the pixel region; A first support layer is formed on the first sacrificial layer and the first nanopillar in the pixel region and the peripheral region; A via is formed in the first support layer to expose a portion of the first sacrificial layer in the pixel region; While retaining a portion of the first sacrificial layer in the peripheral region, the portion of the first sacrificial layer in the pixel region is removed through the via; A second support layer is formed that overlaps with and fills the through-holes of the first support layer; as well as A second nanopillar is formed on the second support layer.

14. The method according to claim 13, wherein, The steps for forming the through hole include: A mask pattern covering the peripheral area is formed on the first support layer; An oriented self-assembly DSA pattern is formed on the first support layer not covered by the mask pattern; and The first support layer is etched using the DSA pattern as an etching mask.

15. The method according to claim 14, wherein, The steps for forming the DSA pattern include: A neutral layer and a DSA material layer are formed in the area where the mask pattern is not formed; Annealing the DSA material layer to separate the DSA material layer into a first polymer block component and a second polymer block component; and The first polymer block component is selectively removed.

16. The method according to claim 13, wherein, The steps for removing the first sacrificial layer include: The first support layer with the vias formed thereon is used as an etching mask to perform the O2 plasma process.

17. The method according to claim 13, wherein, The steps for removing the first sacrificial layer include: A first air layer is formed by removing the first sacrificial layer disposed between the first nanopillars.

18. The method according to claim 13, wherein, The steps for forming the second support layer include: While filling the through-hole, a second support layer is formed on the top and bottom surfaces of the first support layer.

19. The method according to claim 13, wherein, The steps for forming the second support layer include: A second support layer is formed to cover the side surface of the first nanopillar.

20. The method according to claim 13, wherein, The steps for forming the second nanopillar include: A second sacrificial layer is formed on the second support layer; The second nanopillar is formed in the second sacrificial layer; and A second air layer is formed between the second nanopillars by removing the second sacrificial layer.

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