Image sensing device

Abstract

An image sensing device includes a plurality of color filter blocks each including a plurality of color filters arranged adjacent to each other in a first direction and a second direction perpendicular to the first direction and having a same color, a first lattice structure including a first air layer and disposed between the color filter blocks adjacent to each other in the first direction, a second lattice structure including a second air layer and disposed between the color filter blocks adjacent to each other in the second direction, and a third lattice structure including a third air layer and disposed between the color filters within each of the color filter blocks. The first air layer to the third air layer are structurally separated from each other.

Description

Technical Field

[0001] The technology and implementation methods disclosed in this patent document generally relate to an image sensing device. Background Technology

[0002] Image sensors are used in electronic devices to convert optical images into electrical signals. With the recent development of the automotive, medical, computer, and communications industries, the demand for highly integrated, higher-performance image sensors has increased rapidly in various electronic devices such as digital cameras, camcorders, personal communication systems (PCS), video game consoles, surveillance cameras, medical miniature cameras, and robots.

[0003] Image sensing devices can be broadly categorized into CCD (Charge-Coupled Device) image sensing devices and CMOS (Complementary Metal-Oxide-Semiconductor) image sensing devices. Compared to CMOS image sensing devices, CCD image sensing devices offer better image quality, but they tend to consume more power and are larger. CMOS image sensing devices, on the other hand, are smaller and consume less power than CCD image sensing devices. Furthermore, the use of CMOS manufacturing technology to fabricate CMOS sensors allows the photosensitive element and other signal processing circuitry to be integrated into a single chip, enabling the production of miniaturized image sensing devices at a lower cost. For these reasons, CMOS image sensing devices are being developed for many applications, including mobile devices. Summary of the Invention

[0004] Various embodiments of the disclosed technology relate to an image sensing device including a grid structure with an air layer, which minimizes signal deviation between pixels while improving the structural stability of the grid structure.

[0005] According to an embodiment of the disclosed technology, an image sensing device may include: a plurality of color filter blocks, each color filter block including a plurality of color filters arranged adjacent to each other in a first direction and a second direction perpendicular to the first direction and having the same color; a first grid structure including a first air layer and disposed between the color filter blocks adjacent to each other along the first direction; a second grid structure including a second air layer and disposed between the color filter blocks adjacent to each other along the second direction; and a third grid structure including a third air layer and disposed between the color filters in each color filter block, wherein the first air layer, the second air layer and the third air layer are structurally separated from each other.

[0006] According to another embodiment of the disclosed technology, an image sensing device may include: a color filter block comprising a plurality of color filters arranged adjacent to each other in a first direction and a second direction perpendicular to the first direction; a plurality of first grid structures disposed along boundary regions of a first side and a third side of the color filter block disposed in the first direction; a plurality of second grid structures disposed along boundary regions of a second side and a fourth side of the color filter block disposed in the second direction; and a third grid structure disposed between the color filters within the color filter block, wherein the first grid structures, the second grid structures and the third grid structures include air layers that are structurally separated from each other.

[0007] It will be understood that the above general description and the following detailed description of the disclosed technology are both illustrative and explanatory, and are intended to provide further explanation of the claimed disclosure.

[0008] It is evident from the above description that image sensing devices based on some implementations of the disclosed technology can increase the structural stability of the grid structure, including the air layer, by improving the structure of the grid structure, thereby minimizing signal deviation between pixels. Attached Figure Description

[0009] Figure 1 This is a block diagram illustrating an example of an image sensing device based on some implementations of the disclosed technology.

[0010] Figure 2 It is based on the arrangement of some implementation methods of the disclosed technology. Figure 1 A planar view of the grid structure in the pixel array shown.

[0011] Figure 3A This illustrates some implementation methods based on the disclosed technology. Figure 2 The cross-sectional view of an example pixel array cut by line A-A' is shown.

[0012] Figure 3B This illustrates some implementation methods based on the disclosed technology. Figure 2 The cross-sectional view of an example pixel array cut by line B-B' is shown.

[0013] Figure 3C This illustrates some implementation methods based on the disclosed technology. Figure 2 The cross-sectional view of an example pixel array cut by line C-C' is shown.

[0014] Figures 4A to 4D This illustrates some implementation methods based on the disclosed technology for forming Figure 2 A cross-sectional view of an example method for a grid structure is shown.

[0015] Figure 5 It is based on the arrangement of some implementation methods of the disclosed technology. Figure 1 A planar view of the grid structure in the pixel array shown.

[0016] Figure 6 This is a cross-sectional view showing an example of a grid structure based on some implementations of the disclosed technology.

[0017] Figures 7A to 7D This illustrates some implementation methods based on the disclosed technology for forming Figure 6 A cross-sectional view of an example method for a grid structure is shown. Detailed Implementation

[0018] This patent document provides implementations and examples of image sensing devices, enabling the implementation of the disclosed features in a wider range of applications to achieve one or more advantages. Some implementations of the disclosed technology propose a design for an image sensing device that minimizes signal deviation between pixels while improving the structural stability of the grid structure, including the air layer. The disclosed technology provides various implementations of image sensing devices that can increase the structural stability of the grid structure, including the air layer, by improving the structure of the grid structure, thereby minimizing signal deviation between pixels.

[0019] Reference will now be made in detail to specific embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to include the same or similar parts. In the following description, detailed descriptions of relevant known configurations or functions contained herein will be omitted to avoid obscuring the subject matter.

[0020] Various embodiments will now be described with reference to the accompanying drawings. However, it should be understood that the disclosed technology is not limited to specific embodiments, but includes 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.

[0021] Figure 1 This is a block diagram illustrating some implementations of an image sensing system based on the disclosed technology.

[0022] Reference Figure 1 The image sensing device 100 may include a pixel array 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.

[0023] Pixel array 100 may include a plurality of sub-pixel blocks (PBs) arranged consecutively in the row and column directions. Each sub-pixel block (PB) may include a plurality of unit pixels configured to be photosensitive and operable to generate an electrical signal (pixel signal) in response to incident light through photoelectric conversion. In this case, each sub-pixel block (PB) may include a structure (nona pattern structure) in which unit pixels with color filters of the same color are arranged adjacent to each other in an (N×N) array (where N is a natural number of 3 or greater). The color filters may include a red color filter, a green color filter, and a blue color filter. Adjacent sub-pixel blocks (PBs) may be arranged such that the red, green, and blue color filters are arranged in a suitable color pattern to capture the color information of the image in the incident light, such as a Bayer pattern, where red is 25%, green is 50%, and blue is 25%. A grid structure for preventing crosstalk between color filters may be provided between adjacent color filters.

[0024] The pixel array 100 can receive drive signals (e.g., row selection signals, reset signals, transfer (or transmit) signals, etc.) from the row driver 200. Upon receiving a drive signal, a unit pixel can be enabled to perform the operation corresponding to the row selection signal, reset signal, and transfer signal.

[0025] The row driver 200 can enable the pixel array 100 to perform specific operations on unit pixels in the corresponding row based on control signals provided by controller circuitry such as the timing controller 700. In some implementations, the row driver 200 can select one or more groups of pixels arranged in one or more rows of the pixel array 100. The row driver 200 can generate a row selection signal to select one or more rows from multiple rows. The row driver 200 can sequentially enable a reset signal and a transfer signal for unit pixels arranged in the selected row. The pixel signal generated by the unit pixels arranged in the selected row can be output to the correlated double sampler (CDS) 300.

[0026] The Correlated Double Sampler (CDS) 300 can use correlated double sampling to remove unwanted offset values ​​per unit pixel. In one example, the Correlated Double Sampler (CDS) 300 can remove unwanted offset values ​​per unit pixel by comparing the output voltage of the pixel signal (per unit pixel) obtained before and after the accumulation of photocharge generated by the incident light in the sensing node (i.e., the floating diffuse node FD). As a result, the CDS 300 can obtain pixel signals generated only by the incident light without introducing noise. In some implementations, upon receiving a clock signal from the timing controller 700, the CDS 300 can sequentially sample and hold the voltage levels of the reference signal and pixel signal provided from the pixel array 100 to each of the multiple column lines. That is, the CDS 300 can sample and hold the voltage levels of the reference signal and pixel signal corresponding to each column of the pixel array 100. In some implementations, the CDS 300 can transmit the reference signal and pixel signal of each column as a correlated double sample (CDS) signal to the ADC 400 based on control signals from the timing controller 700.

[0027] ADC 400 is used to convert the analog CDS signal received from CDS 300 into a digital signal. In some implementations, ADC 400 can be implemented as a ramp comparator ADC. The analog-to-digital converter (ADC) 400 compares the ramp signal received from timing controller 700 with the CDS signal received from CDS 300, and therefore outputs a comparison signal indicating the comparison result between the ramp signal and the CDS signal. The ADC 400 can count the level transition times of the comparison signal in response to the ramp signal received from timing controller 700, and can output a count value indicating the counted level transition times to output buffer 500.

[0028] The output buffer 500 can temporarily store column-based image data provided by the ADC 400 based on control signals from the timing controller 170. Image data received from the ADC 400 can also be temporarily stored in the output buffer 500 based on control signals from the timing controller 700. The output buffer 500 can provide an interface to compensate for data rate or transmission rate differences between the image sensing device and other devices.

[0029] The column driver 600 can select a column of the output buffer 500 upon receiving a control signal from the timing controller 700, and sequentially output the image data temporarily stored in the selected column of the output buffer 500. In some implementations, upon receiving an address signal from the timing controller 700, the column driver 600 can generate a column selection signal based on the address signal, which can be used to select a column of the output buffer 500, and can control the image data received from the selected column of the output buffer 500 to be output as an output signal.

[0030] 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. In some implementations, the timing controller 700 may include logic control circuitry, phase-locked loop (PLL) circuitry, timing control circuitry, communication interface circuitry, etc.

[0031] Figure 2 It is arranged in Figure 1 A plan view of the grid structure in the pixel array 100 shown.

[0032] Reference Figure 2 The pixel array 100 may include multiple sub-pixel blocks PB_R, PB_G, and PB_B. A sub-pixel block (PB_R) may include multiple unit pixels (PX_R) configured to generate an electrical signal (pixel signal) corresponding to the incident light through the conversion of incident light. A sub-pixel block (PB_G) may include multiple unit pixels (PX_G) configured to generate an electrical signal (pixel signal) corresponding to the incident light through the conversion of incident light. A sub-pixel block (PB_B) may include multiple unit pixels (PX_B) configured to generate an electrical signal (pixel signal) corresponding to the incident light through the conversion of incident light. Each sub-pixel block PB_R, PB_G, or PB_B may include a structure in which unit pixels PX_R, PX_G, or PX_B with the same color filter are arranged in an (N×N) structure (where N is a natural number of 3 or greater).

[0033] For example, a subpixel block (PB_R) may include nine red pixels (PX_R) with red filters, each red filter transmitting visible light with a first wavelength band. Here, the nine red filters may be arranged in a (3×3) array. A subpixel block (PB_G) may include nine green pixels (PX_G) with green filters, each green filter transmitting visible light with a second wavelength band shorter than the first wavelength band. Here, the nine green pixels (PX_G) may be arranged in a (3×3) array. A subpixel block (PB_B) may include nine green pixels (PX_B) with blue filters, each blue filter transmitting visible light with a third wavelength band shorter than the second wavelength band. Here, the nine blue pixels (PX_B) may be arranged in a (3×3) array. The red subpixel block PB_R, the green subpixel block PB_G, and the blue subpixel block PB_B may be arranged consecutively in a Bayer pattern.

[0034] Figure 2The subpixel blocks PB_R, PB_G, and PB_B are illustrated by example as comprising nine unit pixels arranged in a (3×3) array with the same color filter. In one example, the subpixel blocks PB_R, PB_G, and PB_B may have a "nona" pattern structure. Additionally, although for ease of description... Figure 2 Only four sub-pixel blocks PB_R, PB_G, and PB_B that are adjacent to each other while arranged in the Bayer pattern are shown, but the sub-pixel blocks PB_R, PB_G, and PB_B can be arranged continuously in both the row and column directions.

[0035] In some embodiments of the disclosed technology, the pixel array 100 may include a grid structure ARD to reduce possible crosstalk between adjacent color filters. In some implementations, the grid structure ARD may be formed between the color filters of unit pixel blocks PX_R, PX_G, PX_B. Hereinafter, multiple color filters based on sub-pixel blocks PB_R, PB_G, or PB_B (e.g., Figure 2 The 3×3 adjacent color filters of the same color filter among the 36 adjacent color filters shown will be called a color filter block. Figure 2 In the example, there are 4 pixel blocks, each with 3×3 adjacent pixel units. The color of the color filter blocks is based on a suitable color filter pattern arrangement for color imaging, such as... Figure 2 The Bayer pattern shown.

[0036] In some implementations, the grid structure ARD may include a first grid structure ARD_1, a second grid structure ARD_2, and a third grid structure ARD_3. Each first grid structure ARD_1 may extend in a first direction (e.g., the Y-axis direction) and may be disposed between filter blocks of adjacent sub-pixel blocks PB_R, PB_G, and PB_B. For example, each first grid structure ARD_1 may extend in the first direction and may be disposed between filter blocks, for example, along the boundary between adjacent filter blocks arranged in a second direction perpendicular to the first direction (e.g., the X-axis direction).

[0037] Each second grid structure ARD_2 can extend in the second direction and can be disposed between the color filter blocks of adjacent sub-pixel blocks PB_R, PB_G, and PB_B. For example, each second grid structure ARD_2 can extend in the second direction and can be disposed between color filter blocks arranged in the first direction.

[0038] In some implementations of the disclosed technology, the pixel array 100 includes grid structures of different patterns. In one example, grid structures ARD corresponding to some adjacent unit pixels in sub-pixel blocks PB_R, PB_G, or PB_B are connected to each other. In some implementations, the grid structure ARD includes a set of grid structures connected to each other. For example, the third grid structure ARD_3 includes grid structures extending in a first direction and connected to each other in a second direction, such as... Figure 2 As shown.

[0039] Each third grid structure ARD_3 may be positioned between color filters within an area (e.g., each color filter block) surrounded by the first grid structure ARD_1 and the second grid structure ARD_2. For example, each third grid structure ARD_3 may have a hash symbol shape or a square shape, wherein multiple linear grid structures extending in a first direction and multiple other linear grid structures extending in a second direction are integrated into a single structure or connected to each other while being arranged to intersect each other.

[0040] Each of the first grid structures ARD_1 to the third grid structure ARD_3 may include an air layer, and the air layers of the first grid structures ARD_1 to the third grid structures ARD_3 may be separated from each other. The first grid structure ARD_1 and the second grid structure ARD_2 may be arranged around a color filter block, and the vertex regions of the color filter block may be separated from each other, with gaps or openings left at the vertex regions.

[0041] Microlenses for converging incident light can be formed above the color filter. Here, the pixel array 100 may have one microlens per unit pixel or per sub-pixel block PB_R, PB_G, or PB_B.

[0042] Figure 3A It shows along Figure 2 The cross-sectional view of an example pixel array cut by line A-A' is shown. Figure 3B It shows along Figure 2 The cross-sectional view of an example pixel array cut by line B-B' is shown. Figure 3C It shows along Figure 2 The cross-sectional view of an example pixel array cut by line C-C' is shown.

[0043] Reference Figure 2 , Figure 3A , Figure 3B and Figure 3C The pixel array 100 may include a substrate layer 110, a grid structure ARD, a color filter layer 130, and a lens layer 140.

[0044] The substrate layer 110 may include a semiconductor substrate 112, a photoelectric conversion region 114, and a device isolation structure 116.

[0045] Semiconductor substrate 112 may include a bottom surface and a top surface that face away from each other (inwardly facing each other). In some implementations, the bottom surface of semiconductor substrate 112 may be referred to as the front surface, and the top surface of semiconductor substrate 112 may be referred to as the back surface. Here, the back surface may include the surface from which light is incident from the outside. For example, substrate 112 may be a P-type or N-type bulk substrate, a substrate formed by growing a P-type or N-type epitaxial layer on a P-type bulk substrate, or a substrate formed by growing a P-type or N-type epitaxial layer on an N-type bulk substrate. Substrate 332 may include P-type or N-type doped regions 333 having P-type or N-type conductive impurities.

[0046] Photoelectric conversion regions 114 may be formed in the semiconductor substrate 112, and each photoelectric conversion region 114 corresponds to a respective unit pixel. The photoelectric conversion regions 114 may perform photoelectric conversion of incident light (e.g., visible light) filtered by the color filter layer 130 to generate photocharge based on the incident light. Each photoelectric conversion region 114 may include N-type impurities. In some implementations, the photoelectric conversion regions 114 may be formed by stacking multiple doped regions. For example, the lower doped region may be formed by implanting N-type impurities. + The doped region can be formed by ion implantation, and the doped region can be formed by N2 implantation. - Ions are used to form the photoelectric conversion region 114. The photoelectric conversion region 114 can be arranged to occupy the largest possible area to increase the fill factor indicating the light receiving efficiency.

[0047] Individual device isolation structures 116 may be formed between photoelectric conversion regions 114 of adjacent unit pixels within the semiconductor substrate 112, thereby isolating the photoelectric conversion regions 114 from each other. The device isolation structure 116 may include a structure in which insulating material is embedded in trenches formed by etching a portion of the semiconductor substrate. For example, the device isolation structure 116 may include trench structures such as back deep trench isolation (BDTI) structures or front deep trench isolation (FDTI) structures. Alternatively, the device isolation structure 116 may include a junction isolation structure formed by implanting impurities (e.g., P-type impurities) into the semiconductor substrate 112 at a high doping concentration.

[0048] The grid structure ARD can be located on the back side of the semiconductor substrate 112 and can be disposed between the color filters of the color filter layer 130 to reduce or minimize possible crosstalk between adjacent color filters. The grid structure ARD can be formed above the device isolation structure 116 to overlap with the device isolation structure 116.

[0049] The grid-structured ARD may include a first grid structure ARD_1 to a third grid structure ARD_3. Each of the first grid structures ARD_1 to the third grid structures ARD_3 may include a light-absorbing layer and a light-reflecting layer. The light-absorbing layer may include a metal layer, and the light-reflecting layer may include an air layer. The metal layer and the air layer may be isolated for each of the first grid structures ARD_1 to the third grid structures ARD_3.

[0050] The first grid structure ARD_1 may include a metal layer 122a, a first capping layer 124, an air layer 126a, and a second capping layer 128. The second grid structure ARD_2 may include a metal layer 122b, a first capping layer 124, an air layer 126b, and a second capping layer 128. The third grid structure ARD_3 may include a metal layer 122c, a first capping layer 124, an air layer 126c, and a second capping layer 128.

[0051] Each of the metal layers 122a to 122c may be formed of a metallic material with high light absorption (e.g., tungsten (W)). In some implementations, each of the metal layers 122a to 122c may be formed by stacking different materials. For example, each of the metal layers 122a to 122c may also include a barrier metal layer (not shown) disposed beneath the tungsten (W) layer. The metal layers 122a to 122c may be separable from each other.

[0052] Air layers 126a to 126c may be formed above the first capping layer 124 to overlap with metal layers 122a to 122c, respectively. Each of the air layers 126a to 126c may be filled with air. The air layers 126a to 126c may also be separated from each other. In other words, each of the first grid structure ARD_1 to the third grid structure ARD_3 may include a hybrid structure of stacked metal layers and air layers.

[0053] The first capping layer 124 may include a nitride layer and may be formed to extend beneath the color filter layer 130 while covering the metal layers 122a to 122c. The first capping layer 124 prevents the metal layers 122a to 122c from expanding during the thermal annealing process. In this case, the region formed beneath the color filter layer 130 can be used as part of an anti-reflective layer.

[0054] The second capping layer 128 may be a material film formed on the outermost layer of the first grid structure ARD_1 to the third grid structure ARD_3, and may define regions in the first grid structure ARD_1 to the third grid structure ARD_3 where air layers 126a to 126c are formed, respectively. The second capping layer 128 may include an oxide layer. The second capping layer 128 may be formed to extend below the color filter layer 130 while covering the air layers 127 and the metal layers 122a to 122c. The oxide layer may include an ultra-low temperature oxide (ULTO) film, such as a silicon oxide (SiO2) film. In this case, the region in the second capping layer 128 formed below the color filter layer 130 may be used as part of an anti-reflective layer.

[0055] In each of the first capping layer 124 and the second capping layer 128, the region formed below the color filter layer 130 can be used as an anti-reflective layer to compensate for the difference in refractive index between the color filter layer 130 and the substrate 112, so that light that has passed through the color filter layer 130 can be effectively incident into the substrate 112.

[0056] Color filter layer 130 may include color filters that filter visible light from incident light received through lens layer 140 and transmit the filtered light to corresponding photoelectric conversion element 114. Color filter layer 130 may include multiple red color filters, multiple green color filters, and multiple blue color filters. Each red color filter can transmit red visible light having a first wavelength band. Each green color filter can transmit green visible light having a second wavelength band shorter than the first wavelength band. Each blue color filter can transmit blue visible light having a third wavelength band shorter than the second wavelength band. Color filter layer 130 may be formed above substrate layer 110 in a region defined by first grid structure ARD_1 to third grid structure ARD_3.

[0057] Lens layer 140 may include an outer coating layer 142 and a plurality of microlenses 144. The outer coating layer 142 may be formed over color filter layer 130. The outer coating layer 142 may operate as a planarization layer to compensate for (or remove) step differences caused by color filter layer 130. Microlenses 144 may be formed over outer coating layer 142. Each microlens 144 may be formed in a hemispherical shape and may be formed for each of unit pixels PX_R, PX_G, and PX_B or sub-pixel blocks PB_R, PB_G, and PB_B. Microlenses 144 may converge incident light and may transmit the converged light to a corresponding color filter. The outer coating layer 142 and microlenses 144 may be formed of the same material.

[0058] As described above, a grid structure ARD based on some implementations of the disclosed technology may include air layers. The air layers of different grid structures are not connected to each other, and the air layers of the first grid structure ARD_1 to the third grid structure ARD_3 are structurally separated from each other, thereby dispersing the pressure in the grid structure ARD.

[0059] In some example implementations, the grid structure is formed as a mesh structure, in which the air layers of the entire pixel array 100 are interconnected to a single region. When the air layers expand due to manufacturing processes or the environment surrounding the air layers (e.g., high-temperature conditions), vulnerable points may exist in specific portions of the second capping layer 128 due to pressure concentrated in those specific portions. Such vulnerable points can cause the second capping layer 128 to collapse or be damaged due to the pressure concentrated in those specific portions. The internal pressure at the vulnerable point can increase proportionally with the increase in temperature and volume of the air layers. In the case of a mesh structure where the air layers of the entire pixel array 100 are interconnected to a single region, pressure corresponding to the volume of the air layers of the entire grid structure can be applied to the vulnerable point, causing the pixel array in the vulnerable point to collapse or be damaged.

[0060] On the other hand, as described above, when the first grid structure ARD_1 to the third grid structure ARD_3 have separate air layers, the air pressure applied to the vulnerable point can be distributed among the first grid structure ARD_1 to the third grid structure ARD_3, rather than concentrated at a specific location of the air layer of the entire grid structure ARD, thereby minimizing the possible damage to the air grid structure.

[0061] Furthermore, as described above, if each of the sub-pixel blocks PB_R, PB_G, and PB_B comprises nine unit pixels of the same color arranged in a (3×3) array, the unit pixels located in the central portion of each sub-pixel block are in contact with unit pixels of the same color in four directions, but the unit pixels in the outermost region of each sub-pixel block are in contact with unit pixels of other colors. Therefore, when crosstalk occurs, the outermost unit pixels of sub-pixel blocks PB_R, PB_G, and PB_B may be affected by adjacent pixels of different colors. Therefore, in some embodiments, the disclosed technique can be implemented to reduce the signal deviation between the outermost unit pixels in each sub-pixel block by forming a grid structure in a regular shape.

[0062] Therefore, in some embodiments of the disclosed technology, each of the grid structures ARD_1 and ARD_2 in the boundary region between the color filter blocks of sub-pixel blocks PB_R, PB_G, and PB_B can be formed as a linear shape extending in a first or second direction, thereby surrounding the color filter block. Additionally, the grid structure ARD_3 in the region defined by grid structures ARD_1 and ARD_2 can be formed as a hash symbol shape or a square shape separate from grid structures ARD_1 and ARD_2.

[0063] Therefore, in the outermost region of each of the sub-pixel blocks PB_R, PB_G, and PB_B, the color filter of the unit pixel at the vertex of the sub-pixel blocks PB_R, PB_G, and PB_B can be surrounded by the first grid structure ARD_1 to the third grid structure ARD_3, and the color filter of the unit pixel spaced apart from the vertex of the sub-pixel blocks PB_R, PB_G, and PB_B can be surrounded by the third grid structure ARD_3 and any one of the first grid structure ARD_1 and the second grid structure ARD_2.

[0064] Figures 4A to 4D It shows the method used to form Figure 2 The diagram shows a cross-sectional view of an example method for a grid structure ARD. Since the first grid structures ARD_1 to the third grid structures ARD_3 have the same cross-sectional structure, the following description of some implementations of the first grid structures ARD_1 to the third grid structures ARD_3 based on the disclosed technology will refer to the same figures without describing them separately.

[0065] Reference Figure 4A Metal layers 122a to 122c may be formed over the substrate layer 110, which includes the device isolation structure 116 and the photoelectric conversion region 114.

[0066] For example, after forming a metal layer over substrate layer 110, a mask pattern, such as a photoresist pattern (not shown), may be formed over the metal layer to define the area to be used to form the lattice structure ARD. In this case, the metal layer may include tungsten. Subsequently, the mask pattern may be used as an etching mask to etch the metal layer, thereby forming metal layers 122a to 122c.

[0067] Subsequently, a first capping layer 124 may be formed over the substrate layer 110 and the metal layers 122a to 122c. The first capping layer 124 may include a nitride layer.

[0068] Reference Figure 4B Sacrificial layer patterns 125a to 125c can be formed in the regions on the first capping layer 124 where air layers 126a to 126c are to be formed.

[0069] For example, after forming a sacrificial layer (not shown) over the entire first capping layer 124, a mask pattern (photoresist pattern) (not shown) may be formed over the sacrificial layer to define the areas to be used for forming air layers 126a to 126c. In this case, the sacrificial layer may comprise a carbon spin-coated carbon (SOC) film. Subsequently, the mask pattern may be used as an etching mask to etch the sacrificial layer, thereby forming sacrificial layer patterns 125a to 125c.

[0070] Reference Figure 4C A second capping layer 128 may be formed over the first capping layer 124 and the sacrificial layer patterns 125a to 125c.

[0071] In this case, the capping layer 128 may include an ultra-low temperature oxide (ULTO) film. In some implementations, the second capping layer 128 may be formed to a predetermined thickness through which molecules formed by combining the gas used in the plasma process with the carbon of the sacrificial layer patterns 125a to 125c can be easily discharged to the outside.

[0072] Reference Figure 4D , can Figure 4C A plasma process is performed on the resulting structure such that the sacrificial layer patterns 125a to 125c can be removed and air layers 126a to 126c can be formed at the locations where the sacrificial layer patterns 125a to 125c are removed. In this case, a gas including at least one of oxygen, nitrogen, and hydrogen (e.g., O2, N2, H2, CO, CO2, or CH4) can be used to perform the plasma process.

[0073] For example, if in Figure 4C If the O2 plasma process is performed on the obtained structure, then oxygen free radicals (O2 plasma) will be generated. ) can flow through the second capping layer 128 into the sacrificial layer patterns 125a to 125c, and include oxygen free radicals (O) in the sacrificial layer It can combine with the carbon in the sacrificial layer pattern 125 to form CO or CO2. The formed CO or CO2 can be emitted to the outside through the second capping layer 128.

[0074] As a result, the sacrificial layer patterns 125a to 125c can be removed, and air layers 126a to 126c can be formed at the locations where the sacrificial layer patterns 125a to 125c are removed.

[0075] Subsequently, a color filter layer 130 may be formed above the second capping layer 128 to fill the area defined by the grid structure ARD, and a lens layer 140 may be formed above the color filter layer 130.

[0076] Figure 5 It is based on the arrangement of some implementation methods of the disclosed technology. Figure 1 A plan view of the grid structure in the pixel array 100 shown.

[0077] Reference Figure 5 The pixel array 100 may include multiple sub-pixel blocks PB_R, PB_G, and PB_B. Each sub-pixel block PB_R, PB_G, or PB_B may include a structure in which unit pixels PX_R, PX_G, or PX_B with the same color filter are arranged in an (N×N) structure (where N is a natural number of 3 or greater).

[0078] A grid structure ARD' can be formed between the color filters of unit pixels PX_R, PX_G, and PX_B to prevent crosstalk between adjacent color filters.

[0079] In some implementations, the grid structure ARD' includes a first grid structure ARD_1', which includes a grid structure extending in a first direction (e.g., the Y-axis direction) and two grid structures extending in a second direction (e.g., the X-axis direction) and connected to the grid structure extending in the first direction. In some implementations, the grid structure ARD' also includes a second grid structure ARD_2', which includes a grid structure extending in the second direction and two grid structures extending in the first direction and connected to the grid structure extending in the second direction. In some implementations, the grid structure ARD' also includes a third grid structure ARD_3', which includes two grid structures extending in the second direction and two grid structures extending in the first direction and connected to the grid structure extending in the second direction.

[0080] In some embodiments of the disclosed technology, the grid structure ARD' may include a first grid structure ARD_1' and a second grid structure ARD_2' disposed between filter blocks of adjacent sub-pixel blocks PB_R, PB_G and PB_B, and may also include a third grid structure ARD_3' surrounded by the first grid structure ARD_1' and the second grid structure ARD_2' and located at the center of the filter blocks.

[0081] For example, a first grid structure ARD_1' may include a grid structure extending in a first direction and having a first length, and multiple grid structures each extending in a second direction and having a second length shorter than the first length. The grid structures extending in the first direction and the multiple grid structures each extending in the second direction are arranged to intersect each other and connect to each other or integrate into a single structure. Each second grid structure ARD_2' may include a grid structure extending in the second direction and having a first length, and multiple grid structures each extending in the first direction and having a second length. The grid structures extending in the second direction and the multiple grid structures each extending in the first direction are arranged to intersect each other and connect to each other or integrate into a single structure. The first grid structure ARD_1' and the second grid structure ARD_2' may be configured to cover at least two surfaces of the outermost color filter of the color filter block, leaving gaps or openings in the vertex regions of the color filter block. The third grid structure ARD_3' may be formed as a ring shape surrounding a unit pixel located at the center of each of the sub-pixel blocks PB_R, PB_G, and PB_B.

[0082] Therefore, in the unit pixel of the outermost region of each of the sub-pixel blocks PB_R, PB_G, and PB_B, the color filter of the unit pixel (vertex pixel) at the vertex of the sub-pixel blocks PB_R, PB_G, and PB_B can be surrounded by the first grid structure ARD_1' and the second grid structure ARD_2', and the color filter of the unit pixel set between the vertex pixels can be surrounded by the third grid structure ARD_3' and any one of the first grid structure ARD_1' and the second grid structure ARD_2'.

[0083] Each of the first grid structures ARD_1' to the third grid structure ARD_3' may include an air layer, and the air layers of the first grid structures ARD_1' to the third grid structures ARD_3' may be isolated from or separated from each other. The first grid structures ARD_1' to the third grid structures ARD_3' may have the same characteristics as... Figure 2 The same cross-sectional structure in the grid structure ARD. For example, each of the first grid structure ARD_1' to the third grid structure ARD_3' may have a hybrid structure with air layers and metal layers stacked together.

[0084] Figure 6 This is a cross-sectional view showing an example of a grid structure based on some implementations of the disclosed technology.

[0085] Reference Figure 6 Each of the grid structures ARD and ARD' may include a metal layer 121, an air layer 123, a first capping layer 127, and a second capping layer 129.

[0086] A metal layer 121 may be disposed above the substrate layer 110. The metal layer 121 may be formed of a metal material with high light absorption (e.g., tungsten), or it may be formed by stacking different types of materials.

[0087] An air layer 123 may be disposed above the metal layer 121 to contact the metal layer 121.

[0088] The first capping layer 127 may be formed to cover the metal layer 121 and the air layer 123. The first capping layer 127 may be an ultra-low temperature oxide (ULTO) film, such as a silicon oxide (SiO2) film.

[0089] A second capping layer 129 may be formed over a first capping layer 127 to cover the metal layer 121, the air layer 123, and the first capping layer 127. That is, the stacked structure of the metal layer 121 and the air layer 123 may cover a double layer of the first capping layer 127 and the second capping layer 129. The second capping layer 129 may include silicon oxynitride (Si). x O y N z (where each of "x", "y", and "z" is a natural number) film and silicon nitride (Si x N y The second capping layer 129 is an insulating layer of at least one of the films (where each of "x" and "y" is a natural number). The second capping layer 129 may be thicker than the first capping layer 127 to stably maintain the shape of the grid structure. The second capping layer 129 may be formed of the same material as the first capping layer 127.

[0090] Although for ease of description, the above embodiments disclose a stacked structure of each of the grid structure ARD and ARD' including a metal layer and an air layer, the scope or spirit of the disclosed technology is not limited thereto. It should be noted that each of the grid structure ARD and ARD' does not include a metal layer and only allows the air layer to be covered by a capping layer.

[0091] Figures 7A to 7D This demonstrates the formation of some implementation methods based on the disclosed technology. Figure 6 A cross-sectional view of an example method for a grid structure is shown.

[0092] Reference Figure 7A A metal layer 121 and a sacrificial layer pattern 125 can be formed over a substrate layer 110 including a photoelectric conversion region 114 and a device isolation structure 116.

[0093] For example, after sequentially stacking a metal layer and a sacrificial layer over the substrate layer 110, a mask pattern (photoresist pattern) (not shown) can be formed over the sacrificial layer to define the area to be used to form the lattice structure. In this case, the metal layer may include tungsten, and the sacrificial layer may include a carbon spin-coated carbon (SOC) film. Subsequently, the mask pattern can be used as an etching mask to etch the metal layer and the sacrificial layer, thereby forming the metal layer 121 and the sacrificial layer pattern 125.

[0094] Reference Figure 7B A first capping layer 127 may be formed over the substrate layer 110, the metal layer 121, and the sacrificial layer pattern 125. The first capping layer 127 may include an ultra-low temperature oxide (ULTO) film. In some implementations, the first capping layer 127 may be formed to a predetermined thickness through which molecules formed by combining the gas used in the plasma process with the carbon of the sacrificial layer pattern 125 can be easily discharged to the outside.

[0095] Reference Figure 7C , can Figure 7B A plasma process is performed on the resulting structure so that the sacrificial layer pattern 125 can be removed and an air layer 123 can be formed at the location where the sacrificial layer pattern 125 has been removed, such as... Figure 4D As described in the text.

[0096] Reference Figure 7D A second capping layer 129 may be formed above the first capping layer 127. The second capping layer 129 may include silicon oxynitride (SiO2). x O y N z (where x, y, and z are natural numbers) film and silicon nitride (Si x N y An insulating layer of at least one of the films (where x and y are natural numbers). The second capping layer 129 may be thicker than the first capping layer 127 to stably maintain the shape of the grid structure. The second capping layer 129 may be formed of the same material as the first capping layer 127.

[0097] It is evident from the above description that image sensing devices based on some implementations of the disclosed technology can increase the structural stability of the grid structure, including the air layer, by forming a specific pattern for the grid structure, thereby minimizing signal deviation between pixels.

[0098] The implementation of the disclosed technology can provide various effects that can be directly or indirectly identified through the aforementioned patent documents.

[0099] Although several exemplary embodiments have been described, it should be understood that modifications or enhancements to the disclosed embodiments and other embodiments may be conceived based on what is described or shown in this patent document.

[0100] Cross-reference to related applications

[0101] This patent document claims priority and benefit to Korean Patent Application No. 10-2021-0159553, filed on November 18, 2021, 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: Multiple color filter blocks, each color filter block comprising multiple color filters arranged adjacent to each other in a first direction and a second direction perpendicular to the first direction and having the same color; A first grid structure, the first grid structure including a first air layer and disposed between the color filter blocks adjacent to each other along the first direction; A second grid structure, the second grid structure including a second air layer and disposed between the color filter blocks adjacent to each other along the second direction; as well as A third grid structure, comprising a third air layer and disposed between the color filters within each of the color filter blocks, is also included. The first air layer to the third air layer are structurally separated from each other.

2. The image sensing device according to claim 1, wherein, The color filters with the same color in each of the color filter blocks are arranged in an (N×N) structure, where N is a natural number greater than or equal to 3.

3. The image sensing device according to claim 1, wherein, The first grid structure extends in the first direction.

4. The image sensing device according to claim 3, wherein, The second grid structure extends in the second direction.

5. The image sensing device according to claim 4, wherein, The third grid structure includes a plurality of first branch grid structures extending in the first direction and a plurality of second branch grid structures extending in the second direction, wherein the first branch grid structures and the second branch grid structures are arranged to intersect and connect with each other.

6. The image sensing device according to claim 1, wherein, In the color filters located in the outermost region of each of the color filter blocks, the vertex color filters adjacent to the vertices of each color filter block are surrounded by the first grid structure to the third grid structure; and The remaining color filters, other than the vertex color filter, are surrounded by either the first grid structure or the second grid structure, as well as the third grid structure.

7. The image sensing device according to claim 1, wherein, The first grid structure includes a grid structure that is connected to each other and arranged to intersect each other, extending in the first direction, and a plurality of grid structures that extend in the second direction.

8. The image sensing device according to claim 7, wherein, The second grid structure includes a grid structure that is connected to each other and arranged to intersect each other, extending in the second direction, and a plurality of grid structures that extend in the first direction.

9. The image sensing device according to claim 8, wherein, The third grid structure is formed as a ring shape around a unit pixel located in the central part of the color filter block.

10. The image sensing device according to claim 1, wherein, In the color filters located in the outermost region of each of the color filter blocks, the vertex color filters adjacent to the vertices of each color filter block are surrounded by the first grid structure and the second grid structure; and The remaining color filters, other than the vertex color filter, are surrounded by either the first grid structure or the second grid structure, as well as the third grid structure.

11. The image sensing device according to claim 1, wherein, Each of the first to the third grid structures further includes: A metal layer is disposed below each of the first to third air layers.

12. The image sensing device according to claim 11, wherein, The first grid structure to the third grid structure include: A first capping layer, disposed between the metal layer and the first air layer to the third air layer; and A second capping layer is formed to cover the first air layer to the third air layer.

13. The image sensing device according to claim 11, wherein, The first grid structure to the third grid structure further include: A first capping layer, formed to cover the metal layer and the first air layer to the third air layer; and A second capping layer is formed on top of the first capping layer.

14. The image sensing device according to claim 1, wherein, The color filter block includes: A first color filter block, wherein a plurality of first color filters having a first color are arranged adjacent to each other; A second color filter block, which is adjacent to the first color filter block in the first direction, and includes a plurality of second color filters having a second color arranged adjacent to each other; and A third color filter block is adjacent to the second color filter block in the second direction and includes a plurality of third color filters having a third color arranged adjacent to each other.

15. An image sensing device, the image sensing device comprising: A color filter block comprising a plurality of color filters arranged adjacent to each other in a first direction and in a second direction perpendicular to the first direction; A plurality of first grid structures are arranged along the boundary regions of the first and third sides of the color filter block in the first direction; A plurality of second grid structures are arranged along the boundary regions of the second and fourth sides of the color filter block in the second direction; as well as A third grid structure is disposed between the color filters within the color filter block. The first to the third grid structures include air layers that are structurally separated from each other.

16. The image sensing device according to claim 15, wherein, The color filter is a color filter with the same color.

17. The image sensing device according to claim 15, wherein, The first grid structure extends in the second direction and the second grid structure extends in the first direction.

18. The image sensing device according to claim 17, wherein, The third grid structure includes a plurality of grid structures extending in the first direction and a plurality of other grid structures extending in the second direction, wherein the grid structures and the other grid structures are connected to each other and arranged to intersect each other.

19. The image sensing device according to claim 15, wherein, Each of the first grid structure and the second grid structure includes a grid structure extending in the first direction and other grid structures extending in the second direction, wherein the grid structures and other grid structures are connected to each other and arranged to intersect each other.

20. The image sensing device according to claim 19, wherein, The third grid structure is formed as a ring shape around a unit pixel located in the central part of the color filter block.

Images