Image sensing device

Abstract

The present invention relates to an image sensing device, which may include: an image sensing pixel array, which includes a plurality of image sensing pixels operable to respond to light and generate imaging pixel signals; and a first grid structure, which is arranged between the image sensing pixels to separate adjacent image sensing pixels. The image sensing pixel array is constructed to include a central area located at or near the center of the image sensing pixel array, a first diagonal edge area and a second diagonal edge area arranged on opposite sides of the central area in a first diagonal direction, and a third diagonal edge area and a fourth diagonal edge area arranged on opposite sides of the central area in a second diagonal direction different from the first diagonal direction. The first grid structure includes a curved portion in at least one of the first to fourth diagonal edge areas to cover one vertex and adjacent portions of each image sensing pixel to separate the imaging pixel from adjacent image sensing pixels.

Description

Technical Field

[0001] The techniques and implementations disclosed in this patent document generally relate to an image sensing device. Background Art

[0002] An image sensor is a semiconductor device for capturing light of an optical image and converting it into an electrical signal for displaying the captured image and for further processing the captured image. The development of various industries and sectors including the computer, automotive, medical, and communication industries has created various demands for advanced image sensors in various devices and systems such as smartphones, digital cameras, game consoles, IOT (Internet of Things), robots, security cameras, and medical miniature cameras.

[0003] One common type of image sensing device is the charge coupled device (CCD) that has long dominated the field of image sensors. Another common type of image sensing device is the complementary metal oxide semiconductor (CMOS) image sensing device. CCD image sensors are superior to CMOS image sensors in terms of noise characteristics and image quality. However, due to specific advantages relative to CCD image sensors (including, for example, higher frame rates and shutter speeds), CMOS image sensors are now widely used. In addition, CMOS image sensors and signal processing circuits can be integrated into a single chip, making it possible to miniaturize electronic devices while achieving low power consumption. In addition, the use of CMOS manufacturing technology can lead to reduced production costs. These characteristics make CMOS image sensors more suitable for implementation in mobile devices. Summary of the invention

[0004] Embodiments of the disclosed technology are directed to image sensors including a single grid structure that can achieve uniform optical characteristics.

[0005] In an embodiment, an image sensing device may include: an image sensing pixel array including a plurality of image sensing pixels operable to respond to light and generate imaging pixel signals; and a first grid structure disposed between the plurality of image sensing pixels to separate adjacent image sensing pixels. The image sensing pixel array is constructed to include a central region located at or near the center of the image sensing pixel array, a first diagonal edge region and a second diagonal edge region disposed on opposite sides of the central region in a first diagonal direction, and a third diagonal edge region and a fourth diagonal edge region disposed on opposite sides of the central region in a second diagonal direction different from the first diagonal direction. The first grid structure includes a curved portion in at least one of the first to fourth diagonal edge regions to cover one vertex and adjacent portions of each image sensing pixel to separate the imaging pixel from adjacent image sensing pixels.

[0006] In an embodiment, an image sensing device may include: an image sensing pixel array, which includes an array of image sensing pixels to detect incident light to generate a pixel signal representing an image carried by the incident light; a lens, which is placed relative to the image sensing pixel array to receive the incident light and guide it to the image sensing pixel array for detection; and a plurality of isolation structures, which are arranged between adjacent image sensing pixels of the image sensing pixel array, each isolation structure is constructed to include a portion filled with air to provide optical isolation between adjacent image sensing pixels. A plurality of isolation structures located in a central area of ​​the image sensing pixel array around the optical axis of the lens are symmetrically located on four sides of each image sensing pixel. A plurality of isolation structures located in a peripheral area of ​​the image sensing pixel array away from the optical axis of the lens include a curved isolation structure covering a vertex of each image sensing pixel farthest from the optical axis of the lens and a portion of the adjacent side of the vertex.

[0007] Based on this embodiment, not only the stability of the individual grid structures can be ensured, but also the optical uniformity in the entire pixel array can be guaranteed.

[0008] In addition, various effects that can be directly or indirectly determined by this document can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram illustrating an image sensor according to an embodiment of the disclosed technology.

[0010] Figure 2 It is schematically shown Figure 1 FIG. 1 is a diagram of an example of a pixel array.

[0011] Figure 3A It shows the incident Figure 2 Figure 2 is an example of light falling on a pixel array.

[0012] Figure 3B It shows the incident Figure 2 FIG. 1 is another example of light on a pixel array.

[0013] Figure 4A It is shown Figure 2 An example of the central region is shown in the figure.

[0014] Figure 4B yes Figure 4A A stereogram of the central area is shown.

[0015] Figure 5 It is shown along Figure 4A A diagram showing an example of a cross section of a central region taken along a cutting plane line is shown.

[0016] Figure 6 It is shown along Figure 4AA diagram showing an example of a cross section of a central region taken along a cutting plane line is shown.

[0017] Figure 7 It is shown Figure 2 A diagram of an embodiment of a first horizontal edge region is shown.

[0018] Figure 8 It is shown along Figure 7 FIG. 1 is a diagram showing an example of a cross section of a first horizontal edge region taken along a cutting plane line.

[0019] Fig. 9 It is shown Figure 2 A diagram of an example of a first diagonal edge region is shown.

[0020] Fig.10 It is shown along Fig. 9 A diagram showing an example of a cross section of a first diagonal edge region taken along a cutting plane line is shown.

[0021] Fig.11 is a schematic diagram showing the Figure 2 FIG. 1 is a diagram of an example of a first grid structure having different shapes depending on the position of a pixel array. DETAILED DESCRIPTION

[0022] Hereinafter, various embodiments will be described with reference to the accompanying drawings. However, it should be understood that the present patent document is not limited to a specific embodiment, but includes various modifications, equivalents and / or alternatives of the embodiment.

[0023] Figure 1 is a block diagram illustrating an image sensor according to an embodiment of the disclosed technology.

[0024] Reference Figure 1 , the image sensor 100 may include a pixel array 110, a row decoder 120, a CDS (correlated double sampler) 130, an ADC (analog-to-digital converter) 140, an output buffer 150, a column decoder 160, and a timing controller 170. The components of the image sensor 100 are merely examples, and at least some components may be added or omitted if necessary.

[0025] The pixel array 110 may include a plurality of unit pixels arranged in a 2D matrix array. The plurality of unit pixels may convert optical signals into electrical signals based on unit pixels or pixel groups, wherein the unit pixels in the pixel group share internal circuits. The pixel array 110 may receive a drive signal from a row decoder 120, the drive signal including a row selection signal, a pixel reset signal, and a transmission signal. The pixel array 110 may be enabled in response to the drive signal.

[0026] The row decoder 120 may enable the pixel array 110 based on a control signal from the timing controller 170. Specifically, the row decoder 120 may select one or more rows of the pixel array 110. The row decoder 120 may generate a row selection signal to select one or more rows among the multiple rows. The row decoder 120 may sequentially enable a pixel reset signal and a transmission signal for the pixels corresponding to the selected one or more rows. Therefore, a reference signal and an image signal, which are analog signals generated by the pixels of the selected one or more rows, may be sequentially transmitted to the CDS 130. The reference signal and the image signal may be collectively referred to as a pixel signal. The reference signal may be an electrical signal corresponding to a state in which a sensing node (i.e., a floating diffusion node) within a pixel is reset, and the image signal may be an electrical signal corresponding to a state in which a photocharge is accumulated in the sensing node.

[0027] The CDS 130 may sequentially sample and hold reference signals and image signals respectively provided to a plurality of column lines from the pixel array 110. That is, the CDS 130 may sample and hold voltage levels of reference signals and image signals corresponding to respective columns of the pixel array 110.

[0028] The CDS 130 may transmit the reference signal and the image signal of each column as a CDS signal to the ADC 140 based on a control signal from the timing controller 170 .

[0029] The ADC 140 may convert the CDS signal of each column output from the CDS 130 into a digital signal and output the digital signal. The ADC 140 may perform a counting operation and a calculation operation based on the CDS signal of each column and a ramp signal provided from the timing controller 170, and thus may eliminate or reduce noise generated from the pixel (e.g., unique reset noise of each pixel) when generating digital image data from the pixel.

[0030] The ADC 140 may include a plurality of column counters assigned to the respective columns of the pixel array 110, and generate image data by converting CDS signals corresponding to the respective columns into digital signals using the column counters. According to another embodiment, the ADC 140 may include one global counter, and convert CDS signals corresponding to the respective columns into digital signals using a global code provided from the global counter.

[0031] The output buffer 150 may capture the column-based image data provided from the ADC 140 and output the captured image data. The output buffer 150 may temporarily store the image data output from the ADC 140 based on a control signal from the timing controller 170. The output buffer 150 may operate as an interface that compensates for a difference in transfer rate or processing speed between the image sensor 100 and other devices.

[0032] The column decoder 160 may select a column of the output buffer 150 based on a control signal from the timing controller 170 so that the image data temporarily stored in the selected column of the output buffer 150 is sequentially output. Specifically, the column decoder 160 may receive an address signal from the timing controller 170, generate a column selection signal based on the address signal, and select a column of the output buffer 150 so that the image data is output from the selected column of the output buffer 150 as an output signal SO.

[0033] The timing controller 170 may control the row decoder 120 , the ADC 140 , the output buffer 150 , and the column decoder 160 .

[0034] The timing controller 170 may provide a clock signal required for the operation of each component of the image sensor 100, a control signal for timing control, and an address signal for selecting a row or column to the row decoder 120, the column decoder 160, the ADC 140, and the output buffer 150. According to an embodiment, the timing controller 170 may include a logic control circuit, a phase-locked loop (PLL) circuit, a timing control circuit, a communication interface circuit, etc.

[0035] Figure 2 It is schematically shown Figure 1 FIG. 1 is a diagram of an example of a pixel array.

[0036] Reference Figure 2 The pixel array 110 may include a plurality of pixels arranged in a matrix array including a plurality of rows and a plurality of columns. The pixel array 110 may be divided into a plurality of regions according to relative positions of the regions in the pixel array 110.

[0037] The pixel array 110 may include a central region CT, a first horizontal edge region HL, a second horizontal edge region HR, a first vertical edge region VU, a second vertical edge region VD, and first to fourth diagonal edge regions DLU, DRD, DLD, and DRU. Each region included in the pixel array 110 may include a predetermined number of pixels.

[0038] The central region CT may be located at the center of the pixel array 110 .

[0039] The first horizontal edge region HL and the second horizontal edge region HR may be located at edges on both sides of the central region CT of the pixel array 110 along a horizontal line passing through the central region CT. In the present patent document, the edge of the pixel array 110 may indicate a region including pixels within a predetermined distance from the outermost pixels of the pixel array 110.

[0040] The first vertical edge region VU and the second vertical edge region VD may be located at edges of both sides of the central region CT of the pixel array 110 along a vertical line passing through the central region CT.

[0041] The first diagonal edge area DLU may be located at an edge of an upper left side of the central area CT of the pixel array 110 in a first diagonal direction passing through the central area CT. The first diagonal direction may indicate a direction set by rotating a horizontal line at a positive angle.

[0042] The second diagonal edge region DRD may be located at an edge of a lower right side of the central region CT of the pixel array 110 in a first diagonal direction passing through the central region CT.

[0043] The third diagonal edge region DLD may be located at an edge of a lower left side of the central region CT of the pixel array 110 in a second diagonal direction passing through the central region CT. The second diagonal direction may indicate a direction set by rotating a horizontal line at a negative angle.

[0044] The fourth diagonal edge region DRU may be located at an edge of an upper right side of the central region CT of the pixel array 110 in a second diagonal direction passing through the central region CT.

[0045] Figure 3A It shows the incident Figure 2 Figure 2 is an example of light falling on a pixel array.

[0046] Reference Figure 3A , Figure 1 The image sensor 100 shown may also include an objective lens 50. The objective lens 50 may be disposed between the pixel array 110 and an object in front of the image sensor 100 and collect light from the object in front of the image sensor 100. The objective lens 50 may include one or more lenses aligned with an optical axis. The optical axis may pass through the center of the pixel array 110.

[0047] In some implementations, the chief ray can be defined as the ray from an off-axis point in the object that passes through the center of the aperture stop. The chief ray that has passed through the objective lens 50 can be directed in concentric directions around the optical axis. Figure 2 In the figure, the main light of the first horizontal edge area HL is directed from the central area CT toward the left side, the main light of the second horizontal edge area HR is directed from the central area CT toward the right side, the main light of the first vertical edge area VU is directed from the central area CT toward the upper side, and the main light of the second vertical edge area VD is directed from the central area CT toward the lower side. In addition, the main light of the first diagonal edge area DLU is directed from the central area CT toward the upper left side, the main light of the second diagonal edge area DRD is directed from the central area CT toward the lower right side, the main light of the third diagonal edge area DLD is directed from the central area CT toward the lower left side, and the main light of the fourth diagonal edge area DRU is directed from the central area CT toward the upper right side.

[0048] Figure 3AThe cross section of the pixel array 110 taken along the first cutting plane line AA' is schematically shown. Therefore, the central region CT may be located at the center of the pixel array 110, the first horizontal edge region HL may be located at the left side of the central region CT, and the second horizontal edge region HR may be located at the right side of the central region CT.

[0049] The principal ray incident on the central region CT may be vertically incident on the top surface of the pixel array 110. That is, the incident angle of the principal ray incident on the central region CT may be 0° (or an angle approximately equal to 0°).

[0050] However, the principal rays incident on the first horizontal edge region HL and the second horizontal edge region HR may be obliquely incident on the top surface of the pixel array 110. That is, the incident angles of the respective principal rays incident on the first horizontal edge region HL and the second horizontal edge region HR may correspond to a constant angle (an angle greater than 0° and less than 90°). The constant angle may be changed according to the size of the pixel array 110, the curvature of the objective lens 50, the distance between the objective lens 50 and the pixel array 110, etc.

[0051] The main light incident on the area between the central area CT and the first horizontal edge area HL can be as follows: Figure 3A As indicated by the left dotted line of , the main ray incident on the top surface of the pixel array 110 is obliquely incident. However, the incident angle of the main ray incident on the area between the central area CT and the first horizontal edge area HL may be smaller than the incident angle of the main ray incident on the first horizontal edge area HL.

[0052] The principal ray incident on the region between the central region CT and the second horizontal edge region HR may be as follows: Figure 3A The right dotted line of is obliquely incident on the top surface of the pixel array 110. However, the incident angle of the main light incident on the area between the central area CT and the second horizontal edge area HR may be smaller than the incident angle of the main light incident on the second horizontal edge area HR.

[0053] Figure 3A A cross section of the pixel array 110 taken along the first cutting plane line AA' is shown. The cross section of the pixel array 110 taken along the second cutting plane line BB' may be the same as or similar to the cross section of the pixel array 110 taken along the first cutting plane line AA', except that the cross section of the pixel array 110 taken along the second cutting plane line BB' includes the first vertical edge region VU and the second vertical edge region VD instead of the first horizontal edge region HL and the second horizontal edge region HR.

[0054] Figure 3B It shows the incident Figure 2 FIG. 1 is another example of light on a pixel array.

[0055] Figure 3B The cross section of the pixel array 110 taken along the third cutting plane line CC' is schematically shown. Therefore, the central region CT may be located at the center of the pixel array 110, the first diagonal edge region DLU may be located at the left side of the central region CT, and the second diagonal edge region DRD may be located at the right side of the central region CT.

[0056] The principal ray incident on the central region CT may be vertically incident on the top surface of the pixel array 110. That is, the incident angle of the principal ray incident on the central region CT may be 0° (or an angle approximately equal to 0°).

[0057] However, the principal light incident on the first diagonal edge area DLU and the second diagonal edge area DRD may be obliquely incident on the top surface of the pixel array 110. That is, the incident angle of the principal light incident on the first diagonal edge area DLU and the second diagonal edge area DRD may correspond to a constant angle (an angle greater than 0° and less than 90°). The constant angle may change according to the size of the pixel array 110, the curvature of the objective lens 50, the distance between the objective lens 50 and the pixel array 110, etc.

[0058] The principal ray incident on the area between the central region CT and the first diagonal edge region DLU may be as follows: Figure 3B As indicated by the left dotted line of , the main ray incident on the top surface of the pixel array 110 is obliquely incident. However, the incident angle of the main ray incident on the area between the central area CT and the first diagonal edge area DLU may be smaller than the incident angle of the main ray incident on the first diagonal edge area DLU.

[0059] The principal ray incident on the region between the central region CT and the second diagonal edge region DRD may be as follows: Figure 3B The right dotted line of is obliquely incident on the top surface of the pixel array 110. However, the incident angle of the main light incident on the area between the central area CT and the second diagonal edge area DRD may be smaller than the incident angle of the main light incident on the second diagonal edge area DRD.

[0060] Figure 3B A cross section of the pixel array 110 taken along the third cutting plane line CC' is shown. The cross section of the pixel array 110 taken along the fourth cutting plane line DD' may be the same or similar to the cross section of the pixel array 110 taken along the third cutting plane line CC', except that the cross section of the pixel array 110 taken along the fourth cutting plane line DD' includes the third diagonal edge region DLD and the fourth diagonal edge region DRU instead of the first diagonal edge region DLU and the second diagonal edge region DRD.

[0061] Figure 4A It is shown Figure 2 An example of the central region is shown in the figure.

[0062] Reference Figure 4A , the central area 400A is Figure 2 An example of a central region CT is shown. In this patent document, a 3×3 array of nine pixels in the central region 400A will be discussed as an example.

[0063] The central area 400A may include nine pixels P1 to P9 arranged in a 3×3 matrix shape. Here, it should be noted that the consecutive numbers given to the pixels P1 to P9 do not indicate specific pixels within the pixel array 110 but indicate pixels disposed at specific positions in the 3×3 matrix.

[0064] Figure 4A The image sensor array shown may be constructed to include a first grid structure 210, which serves as an optical isolation structure to optically isolate pixels from adjacent pixels, such that pixels P1 to P9 as shown in the central area 400A are physically separated by the first grid structure 210 to provide optical isolation between pixels. The first grid structure 210 may include a low refractive index layer having a refractive index lower than that of its surrounding environment to cause optical reflection of incident light at an oblique angle (including incident light at a large oblique angle that is totally reflected by the first grid structure 210), such as in Figure 8 and Fig.10 In some implementations, the low refractive index layer of the first grid structure 210 may include an air layer (a structure filled with air). In an embodiment of the disclosed technology, the first grid structure 210 may have a double-layer structure of an air layer and a metal layer filled with a metal (e.g., tungsten), as further described in the following examples.

[0065] The first grid structure 210 may be defined as a component included in pixels adjacent to the first grid structure 210 , or a component included in the pixel array 110 for distinguishing between pixels adjacent to the first grid structure 210 . Figure 4A Each of the illustrated pixels P1 to P9 may indicate a light receiving area into which light may be incident.

[0066] In an implementation, the first grid structure 210 may be disposed between pixels adjacent to each other in the row direction of the pixel array 110 (e.g., between P1 and P2, between P2 and P3) or between pixels adjacent to each other in the column direction (or up-down direction) of the pixel array 110 (e.g., P1 and P4, P4 and P7, etc.). The first grid structure 210 may be arranged in the row direction or the column direction of the pixel array 110. The first grid structure 210 may extend along a side of the pixel abutting against the first grid structure 210. The length of the first grid structure 210 extending along a side of the pixel may be equal to or less than the length of a side of the corresponding pixel.

[0067] The first grid structures 210 surrounding the centers of the pixels (eg, P1 , P2 , P4 , and P5 ) arranged in a 2×2 matrix array are isolated from each other.

[0068] like Figure 4A As shown, each first grid structure 210 extending in one direction may have a rounded end. The rounded ends of adjacent first grid structures 210 may be arranged to face each other. Such a rounded structure may advantageously disperse the stress applied to the air layer included in the first grid structure 210 due to high temperature, thereby enhancing the structural stability of the first grid structure 210. In another embodiment of the disclosed technology, at least one surface of each first grid structure 210 may have a rounded structure.

[0069] The gaps between adjacent first grid structures 210 arranged in the row direction of the central area 400A and the gaps between adjacent first grid structures 210 arranged in the column direction of the central area 400A may be defined as gap regions 220. In some implementations, the gap regions 220 do not include a low refractive index layer such as the air layer discussed above. That is, the gap regions 220 may be arranged in the row direction or the column direction of the central area 400A, and the air layer (or other low refractive index layer) of the first grid structure 210 may be physically isolated from the adjacent air layer. In an embodiment of the disclosed technology, a second grid structure including a metal layer may be disposed in the gap regions 220. In some implementations, the gap regions 220 include a metal layer.

[0070] In some implementations, the first grid structure 210 may be continuously disposed even in the gap region 220 , so that the entire air layer 240 of the pixel array 110 is connected to form a mesh-type first grid structure 210 .

[0071] In some implementations, since the first capping film 250 and the second capping film 260 are thin films and may be damaged due to limitations of the manufacturing process and environmental factors such as high pressure and high temperature conditions. For example, the first capping film 250 and the second capping film 260 may include specific points where the first capping film 250 and the second capping film 260 are thinner or weaker than other areas, and the pressure applied to these weak points increases as the temperature and volume of the internal air of the air layer 240 increase. In a mesh structure in which the entire air layer 240 of the pixel array 110 is connected, a pressure corresponding to the volume of the entire air layer 240 of the pixel array 110 may be applied to the weak points. Therefore, bursting may easily occur at the weak points.

[0072] In the grid structures implemented based on some embodiments of the disclosed technology, the air layers 240 of different first grid structures 210 are physically separated, or a group of first grid structures 210 share a common air layer 240, and the air layers 240 of different groups of first grid structures are physically separated by gap regions 220 that do not include the air layers 240. Therefore, by separating the air layers 240, the pressure that would increase in proportion to the entire volume of the air layers 240 of the first grid structures 210 can be reduced.

[0073] Figure 4A The fifth cutting plane line EE' and the sixth cutting plane line FF' are shown, Figure 5 and Figure 6 The structures of a pixel including a first grid structure 210 and a gap region 220 are shown separately, as will be discussed below.

[0074] exist Figure 4A , central region 400A is shown as the center of the 3×3 pixel array, but any region in pixel array 110 may correspond to the structure of central region 400A. However, as described below, the position or shape of first grid structure 210 may vary depending on the relative position within pixel array 110.

[0075] Figure 4B yes Figure 4A A stereogram of the central area is shown.

[0076] Figure 4B A central region 400A corresponding to an example in which the second grid structure including a metal layer is disposed in the gap region 220 is shown.

[0077] The first grid structure 210 may include a low refractive index layer such as an air layer, which is disposed above the metal layer to form a stack of the low refractive index layer and the metal layer. The gap region 220 may include a second grid structure corresponding to the lower metal layer, without an air layer thereon. Therefore, the gap region 220 may physically isolate the air layer of the first grid structure 210 adjacent to the gap region 220.

[0078] Figure 5 It is shown along Figure 4A FIG. 1 is a diagram showing an example of a cross section of a central region taken along a fifth cutting plane line.

[0079] Figure 5 Shown along Figure 4A The cross section 500 taken along the fifth cutting plane line EE' of FIG. 5 is a cross section of the fifth pixel P5 and the second pixel P2 and the eighth pixel P8 located on the upper and lower sides of the fifth pixel P5. The structure of pixels other than the fifth pixel P5 may also be the same as or similar to the fifth pixel P5.

[0080] The cross section 500 taken along the fifth cutting plane line EE′ may include a substrate 270 , an anti-reflection layer 275 , a photoelectric conversion element 280 , an isolation film 290 , a metal layer 230 , an air layer 240 , a first capping film 250 , a second capping film 260 , a color filter 300 , an outer coating 310 , and a microlens 320 .

[0081] The substrate 270 may include a top surface and a bottom surface facing each other. The bottom surface and the top surface of the substrate 270 may be defined as a front surface and a back surface, respectively, but the scope of the disclosed technology is not limited thereto. The substrate 270 may include a P-type or N-type bulk substrate, a substrate obtained by growing a P-type or N-type epitaxial layer in a P-type bulk substrate, or a substrate obtained by growing a P-type or N-type epitaxial layer in an N-type bulk substrate.

[0082] The anti-reflection layer 275 may be disposed on the substrate 270 and compensate for the difference in refractive index between the substrate 270 and the color filter 300, thereby reducing the reflectivity of light directed toward the substrate 270. To this end, the refractive index value of the anti-reflection layer 275 may be between the refractive index value of the substrate 270 and the refractive index value of the color filter 300.

[0083] The photoelectric conversion element 280 may be disposed in a region of the substrate 270 corresponding to the fifth pixel P5. The photoelectric conversion element 280 may generate and accumulate photocharges corresponding to the intensity of light incident on the fifth pixel P5. The photoelectric conversion element 280 may be implemented as at least one of a photodiode, a pin-type photodiode, a photogate, and a phototransistor. The photoelectric conversion element 280 may be formed as an N-type doped region by an ion implantation process of implanting N-type ions. According to an embodiment, the photoelectric conversion element 280 may have a structure in which a plurality of doped regions are stacked. In this case, a lower doped region may be formed by implanting N+ ions, and an upper doped region may be formed by implanting N- ions. The photoelectric conversion element 280 may be formed across as large an area as possible so as to improve a fill factor indicating light receiving efficiency.

[0084] The isolation film 290 may be disposed between the photoelectric conversion elements 280 of adjacent pixels, and may be recessed in a vertical direction to electrically and optically isolate the photoelectric conversion elements 280. For example, the isolation film 290 may be formed by filling a groove with a dielectric material, wherein the groove is vertically and deeply recessed by a DTI (deep trench isolation) process.

[0085] The metal layer 230 may be disposed over the substrate 270. The metal layer 230 may be formed of a metal material having a high light absorption rate, such as tungsten. In an embodiment of the disclosed technology, the metal layer 230 may be formed by stacking different materials.

[0086] The air layer 240 may be disposed above the metal layer 230, and the shape of the air layer 240 may be defined by the first capping film 250. The air layer 240 may be filled with air having a relatively low refractive index (eg, 1).

[0087] The first capping film 250 may be formed to cover the entire air layer 240 and the entire metal layer 230. That is, the first capping film 250 may be in contact with the side surfaces of the air layer 240 and the metal layer 230 and the top surface of the air layer 240. Therefore, the air layer 240 and the metal layer 230 may be physically isolated from the outside by the first capping film 250. For example, the first capping film 250 may be a material such as silicon oxide (SiO 2 )'s ULTO (ultra-low temperature oxide).

[0088] The second capping film 260 may be formed to cover the entire first capping film 250. That is, one surface of the second capping film 260 may be in contact with the first capping film 250, and the other surface of the second capping film 260 may be in contact with the outside of the first grid structure 210. Therefore, the first capping film 250 may be physically isolated from the outside by the second capping film 260. For example, the second capping film 260 may be a film including silicon oxynitride (Si x O y N z ), silicon oxide (Si x O y ) and silicon nitride (Si x N y ) wherein x, y and z are natural numbers.

[0089] The second capping film 260 may have a thickness greater than that of the first capping film 250. This is because the first capping film 250 is formed to be as thin as possible so that internal materials can be effectively discharged to the outside during the plasma process for forming the air layer 240, and the second capping film 260 is formed to have a thickness required to stably maintain the shape of the first grid structure 210 including the air layer 240.

[0090] The air layer 240 may be formed by a series of processes as follows: forming a sacrificial film including a SOC (spin on carbon) film including carbon at a position corresponding to the air layer 240, providing a first capping film 250 to cover the sacrificial film, and then performing a plasma process using a gas including at least one of oxygen, nitrogen, and hydrogen. 2 Plasma process as an example. 2 During the plasma process, oxygen radicals (O*) are introduced into the sacrificial film through the first capping film 250 and are combined with carbon of the sacrificial film to generate CO or CO 2 The generated CO or CO 2 Escapes to the outside through the first capping film 250. Through this process, the sacrificial film may be removed, and the air layer 240 may be formed at a position where the sacrificial film has been removed.

[0091] In another embodiment of the disclosed technology, a supporting film for maintaining the shape of the first grid structure 210 may be formed in a region corresponding to the top of the air layer 240 and the bottom of the first capping film 250 included in the first grid structure 210. Such a supporting film may be a dielectric film having no light absorption property.

[0092] In an embodiment of the disclosed technology, the first capping film 250 and the second capping film 260 may include the same material and have the same refractive index.

[0093] In an embodiment of the disclosed technology, the refractive index of each of the first capping film 250 and the second capping film 260 may be higher than the refractive index of the air layer 240 and lower than the refractive index of the color filter 300 .

[0094] The first grid structure 210 may prevent light incident on the color filter 300 from being directed to another adjacent color filter, thereby minimizing optical crosstalk.

[0095] Specifically, since the refractive index of the air layer 240 filled with air is lower than the refractive index of the color filter (not shown) (e.g., 1.6 to 1.7) and the refractive index of each of the first cover film 250 and the second cover film 260 (e.g., 1.4), the air layer 240 can cause reflection to reflect the incident light into the fifth pixel P5.

[0096] Although reflection of the air layer 240 does not occur but some incident light is refracted into the air layer 240 according to various incident angles, the incident light may be absorbed by the metal layer 230 , which makes it possible to prevent optical crosstalk.

[0097] like Figure 5As shown, the height of the top surface of the color filter 300 may be equal to the height of the first grid structure 210. In other implementations, the height of the top surface of the color filter 300 may be greater than or less than the height of the first grid structure 210.

[0098] although Figure 5 The first grid structure 210 is shown to have a double-layered structure in which the metal layer 230 and the air layer 240 are stacked, but the first grid structure 210 may have a single-layered structure including only the air layer 240 without the metal layer 230 .

[0099] The first capping film 250 and the second capping film 260 constituting the first grid structure 210 disposed on one side of the color filter 300 may extend between the color filter 300 and the substrate 270 and be disposed below the color filter 300. The first capping film 250 and the second capping film 260 disposed below the color filter 300 may be connected to the first capping film 250 and the second capping film 260 constituting the first grid structure 210 disposed on the other side of the color filter 300. That is, the first capping film 250 and the second capping film 260 constituting the first grid structure 210 abutting the color filter 300 may be combined into one structure together with the first capping film 250 and the second capping film 260 disposed below the color filter 300.

[0100] Therefore, the first and second capping films 250 and 260 for maintaining the shape of the first grid structure 210 may contact another component (e.g., substrate 270) across a larger area than when the first and second capping films 250 and 260 are not disposed under the color filter 300. Therefore, the structural stability of the first grid structure 210 may be improved. The balance between the tension generated by the first and second capping films 250 and 260 disposed under the color filter 300 on the left and right sides of the first grid structure 210 may prevent the first grid structure 210 having a smaller width from tilting to the left or right.

[0101] The first capping film 250 and the second capping film 260 disposed under the color filter 300 may be used as an anti-reflection layer, which compensates for the difference in refractive index between the color filter 300 and the substrate 270, so that light passing through the color filter 300 can be effectively guided toward the substrate 270. Therefore, although a separate anti-reflection layer is not disposed between the color filter 300 and the substrate 270, the first capping film 250 and the second capping film 260 may be used as an anti-reflection layer. Therefore, the entire thickness of the fifth pixel P5 can be reduced.

[0102] The color filter 300 may be formed on the substrate 270 and selectively transmit light of a specific wavelength range (e.g., red, green, blue, magenta, yellow, cyan, etc.) In an embodiment of the disclosed technology, when the fifth pixel P5 corresponds to a depth pixel, the color filter 300 may be omitted or replaced by an IR (infrared) pass filter.

[0103] The overcoat layer 310 may be disposed over the color filter 300 and the first grid structure 210 and prevent diffuse reflection of incident light, thereby suppressing glare characteristics. In addition, the overcoat layer 310 may compensate for the height difference between the color filter 300 and the first grid structure 210 so that the microlens 320 has a constant height.

[0104] The microlens 320 may be formed on the overcoat layer 310 and increase light-condensing capability of incident light, thereby improving light-receiving efficiency of the photoelectric conversion element 280 .

[0105] Figure 6 It is shown along Figure 4A FIG. 1 is a diagram showing an example of a cross section of a central region taken along a sixth cutting plane line.

[0106] Figure 6 Shown along Figure 4A The cross section 600 taken along the sixth cutting plane line FF' of the fifth pixel P5 is shown in FIG. That is, the cross section 600 taken along the sixth cutting plane line FF' indicates a cross section of the fifth pixel P5 and portions of the first pixel P1 and the ninth pixel P9 located on the upper and lower sides of the fifth pixel P5. The following description will focus on the cross section of the fifth pixel P5, but other pixels included in the pixel array 110 may also have substantially the same structure.

[0107] A cross section 600 taken along the sixth cutting plane line FF′ may include a substrate 270 , an anti-reflection layer 275 , a photoelectric conversion element 280 , an isolation film 290 , a metal layer 230 , a first capping film 250 , a second capping film 260 , a color filter 300 , an overcoat layer 310 , and a microlens 320 .

[0108] The cross section 600 taken along the sixth cutting plane line FF′ shows that the gap region 220 has a structure in which the air layer 240 is omitted from the first grid structure 210. That is, the gap region 220 may be defined as a second grid structure including the metal layer 230.

[0109] According to another embodiment, when the first grid structure 210 has a single structure including only the air layer 240 without the metal layer 230 , the gap region 220 may not include the metal layer 230 .

[0110] The boundary between the color filters 300 of different unit pixels (eg, P2 and P1 ) may be located above the gap region 220 .

[0111] Figure 7 It is shown Figure 2 A diagram of an embodiment of a first horizontal edge region is shown.

[0112] Reference Figure 7, the first horizontal edge region 700 is Figure 2 An example of the first horizontal edge region is shown. In this patent document, a 3×3 array of nine pixels in the first horizontal edge region 700 will be described as an example.

[0113] The first horizontal edge region 700 may include nine pixels P1 to P9 arranged in a 3×3 matrix shape. Here, it should be noted that the numbers given to the pixels P1 to P9 do not indicate specific pixels within the pixel array 110, but indicate pixels disposed at specific positions in the 3×3 matrix.

[0114] The first horizontal edge region 700 may include a first grid structure 210 and a gap region 220, the gap region 220 being a structure for optical isolation between adjacent pixels P1 to P9. In some implementations, the positions and structures of the first grid structure 210 and the gap region 220 are substantially the same as those of the first grid structure 210 and the gap region 220.

[0115] As reference Figure 3A As described, when viewed from the top, the main light incident on the first horizontal edge region 700 propagates from the right side to the left side of the first horizontal edge region 700. The direction of the main light incident on the first horizontal edge region 700 is defined as a first incident direction.

[0116] Figure 7 A seventh cutting plane line HH' is shown which cuts the pixels P4 to P6 adjacent to each other in the first incident direction of the main light propagation. Figure 8 , the incident path of the principal ray will be described as follows.

[0117] Figure 8 It is shown along Figure 7 FIG. 1 is a diagram showing an example of a cross section of a first horizontal edge region taken along a seventh cutting plane line.

[0118] Figure 8 Shown along Figure 7 The cross section 800 taken along the seventh cutting plane line H-H' of the first horizontal edge region 700 is shown. That is, the cross section 800 taken along the seventh cutting plane line H-H' indicates the cross section of the pixels P4 to P6 adjacent to each other in the first incident direction. The following description will focus on the cross section of the pixels P4 to P6. However, other pixels P1 to P3 or P7 to P9 adjacent to each other in the first incident direction within the first horizontal edge region 700 may have substantially the same structure.

[0119] The cross section 800 taken along the seventh cutting plane line HH′ may include the substrate 270 , the anti-reflection layer 275 , the photoelectric conversion element 280 , the isolation film 290 , the metal layer 230 , the air layer 240 , the color filter 300 , the overcoat layer 310 , and the microlens 320 .

[0120] In some implementations, the structure, function, and materials of the components included in cross section 800 are similar to those of reference Figure 5 The structure, function and materials of the components described in cross section 500 are substantially the same as those of Figure 5 The structure is different. For the convenience of description, Figure 8 The first cover film 250 and the second cover film 260 are omitted. It should be noted that the Figure 5 The same manner includes a first covering film 250 and a second covering film 260.

[0121] The cross section 800 may be divided into a first layer including microlenses 320 and overcoat layer 310 , a second layer including metal layer 230 , air layer 240 and color filter 300 , and a third layer including substrate 270 , anti-reflection layer 275 , photoelectric conversion element 280 and isolation film 290 .

[0122] exist Figure 5 In the cross section 500 of FIG. 5 , the first layer, the second layer, and the third layer may be arranged so that a vertical line passing through a boundary between mutually adjacent microlenses 320 in the first layer, a vertical line passing through the center of the metal layer 230 or the air layer 240 in the second layer, and a vertical line passing through the center of the isolation film 290 in the third layer substantially coincide with each other. In other words, the first layer, the second layer, and the third layer may be arranged so that the optical axes of the microlenses 320 (i.e., a vertical line passing through the center of the microlenses 320, a vertical line passing through the center of the color filter 300, and a vertical line passing through the center of the photoelectric conversion element 280) substantially coincide with each other.

[0123] However, in the first horizontal edge region 700, the main light is incident obliquely on the top surface of the first layer. Therefore, the second layer may be shifted relative to the first layer, and the third layer may be shifted relative to the second layer, so that the main light that has passed through the microlens 320 of the fifth pixel P5 passes through the color filter 300 of the fifth pixel P5 and is incident on the photoelectric conversion element 280 of the fifth pixel P5. That is, a vertical line passing through the center of the metal layer 230 or the air layer 240 in the second layer may be shifted relative to a vertical line passing through the boundary between the microlenses 320 adjacent to each other in the propagation direction of the main light ( Figure 8In addition, a vertical line passing through the center of the isolation film 290 in the third layer may be shifted by a predetermined distance in the propagation direction of the main light relative to a vertical line passing through the center of the metal layer 230 or the air layer 240 in the second layer. The distance by which the second layer is shifted relative to the first layer and the distance by which the third layer is shifted relative to the second layer may be determined experimentally to minimize crosstalk between pixels while maximizing light receiving efficiency. In addition, the distance by which the second layer is shifted relative to the first layer and the distance by which the third layer is shifted relative to the second layer may be equal to or different from each other.

[0124] In the region disposed between the first horizontal edge region 700 and the central region CT, a distance by which the second layer is shifted relative to the first layer and a distance by which the third layer is shifted relative to the second layer may gradually increase from the central region CT toward the first horizontal edge region 700. This is because the incident angle of the main light increases from the central region CT toward the first horizontal edge region 700.

[0125] In the present patent document, the main ray effectively incident on the fifth pixel P5 may have a range from the first ray L1 to the third ray L3. When the main ray is effectively incident, it may indicate that the main ray is incident on the photoelectric conversion element 280 of the fifth pixel P5.

[0126] The first light L1 may be incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0127] The second light L2 may be incident on the color filter 300 , reflected by the metal layer 230 (more specifically, the first and second capping films 250 and 260 covering the metal layer 230 ), and incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0128] The third light L3 may be incident on the color filter 300 , reflected by the air layer 240 , and incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0129] The third light ray L3 as the outermost light ray on one side (i.e., the left side) among the main light rays effectively incident on the fifth pixel P5 may be reflected by the air layer 240 disposed on the left side of the color filter 300 and incident on the photoelectric conversion element 280 of the fifth pixel P5. In addition, the first light ray L1 as the outermost light ray on the other side (i.e., the right side) among the main light rays effectively incident on the fifth pixel P5 may be incident through the microlens 320 of the fifth pixel P5 and incident on the photoelectric conversion element 280 of the fifth pixel P5 through the opening defined by the air layer 240 disposed on the right side of the color filter 300.

[0130] Therefore, the range of the main light effectively incident on the fifth pixel P5 can be determined based on the opening defined by the air layer 240 disposed on both sides of the fifth pixel P5 in the direction of the main light. In other words, the main light effectively incident on the fifth pixel P5 can interact with the air layer 240. This is because the air layer 240 is disposed in the propagation direction of the main light.

[0131] exist Figure 7 and Figure 8 , the first horizontal edge region 700 is described as an example. However, except that the second layer and the third layer are shifted in different directions according to the direction of the main light, substantially the same technical concept can be applied to the second horizontal edge region HR, the first vertical edge region VU, and the second vertical edge region VD. That is, the range of the main light effectively incident on each pixel in the second horizontal edge region HR, the first vertical edge region VU, and the second vertical edge region VD can be determined based on the opening defined by the air layer 240 disposed on both sides of the pixel in the direction of the main light.

[0132] Fig. 9 It is shown Figure 2 A diagram of an example of a first diagonal edge region is shown.

[0133] Reference Fig. 9 , the first diagonal edge region 900 is Figure 2 An example of the first diagonal edge region VLU is shown. In this patent document, for the convenience of description, a 3×3 array of nine pixels in the first diagonal edge region 900 will be described as an example.

[0134] The first diagonal edge region 900 may include nine pixels P1 to P9 arranged in a 3×3 matrix shape. Here, it should be noted that the consecutive numbers given to the pixels P1 to P9 do not indicate specific pixels within the pixel array 110, but indicate pixels disposed at specific positions in the 3×3 matrix.

[0135] The first diagonal edge region 900 may include a first grid structure 210 and a gap region 220 , which is a structure for optical isolation between pixels P1 to P9 adjacent to each other.

[0136] In this example, the first grid structure 210 included in the first diagonal edge region 900 may have a curved shape such as an L shape to cover the left corner or upper left portion of the pixel near the corresponding vertex of the pixel (e.g., P5). The first grid structure 210 may be physically isolated from adjacent first grid structures 210.

[0137] The entire length of the first grid structure 210 having a curved shape such as an L shape may be changed according to the position of the corresponding pixel. For example, as the position of the pixel within the first diagonal edge area DLU becomes closer to the upper left vertex of the pixel array 110, the entire length of the first grid structure 210 may be reduced. This is because, since the direction of the main light becomes closer to the upper left vertex of the corresponding pixel as the position of the pixel becomes closer to the upper left vertex of the pixel array 110, even if the entire length of the first grid structure 210 is reduced, optical uniformity may be maintained. In addition, as the entire length of the first grid structure 210 is reduced, the volume of the air layer 240 may be reduced to further prevent bursting at a weak point.

[0138] As reference Figure 3B As described, when viewed from the top, the principal ray incident on the first diagonal edge region 900 propagates from the lower right to the upper left of the first diagonal edge region 900. The direction of the principal ray incident on the first diagonal edge region 900 is defined as a second incident direction.

[0139] Fig. 9 An eighth cutting plane line II' is shown for cutting pixels P1, P5 and P9 adjacent to each other in the second incident direction of the main light propagation. Fig.10 , the incident path of the principal ray will be described as follows.

[0140] Fig. 9 The first grid structure 210 included in the first diagonal edge region 900 is shown. However, the first grid structure 210 of the second diagonal edge region DRD may have a curved shape such as an L shape to cover the lower right vertex of each pixel, the first grid structure 210 of the third diagonal edge region DLD may have a curved shape such as an L shape to cover the lower left vertex of each pixel, and the first grid structure 210 of the fourth diagonal edge region DRU may have a curved shape such as an L shape to cover the upper right vertex of each pixel.

[0141] That is, the direction from the center of the pixels included in any one of the first to fourth diagonal edge regions DLU, DRD, DLD and DRU toward the vertices of the pixels covered by the L-shaped first grid structure 210 may correspond to the direction from the central area CT of the pixel array 110 toward the diagonal edge region including the pixels among the first to fourth diagonal edge regions DLU, DRD, DLD and DRU.

[0142] For example, a direction from the center of the pixel included in the fourth diagonal edge region DRU toward the upper right vertex covered by the first grid structure 210 may correspond to a direction from the central region CT toward the fourth diagonal edge region DRU including the corresponding pixel.

[0143] Fig.10 It is shown along Fig. 9 FIG. 1 is a diagram showing an example of a cross section of a first diagonal edge region taken along an eighth cutting plane line.

[0144] Fig.10 Shown along Fig. 9 The cross section 1000 taken along the eighth cutting plane line II' of the first diagonal edge region 900 is shown in FIG. That is, the cross section 1000 taken along the eighth cutting plane line II' indicates the cross section of the pixels P1, P5 and P9 adjacent to each other in the second incident direction. The following description will focus on the cross section of the pixels P1, P5 and P9. However, other pixels (e.g., P4 and P8) adjacent to each other in the second incident direction within the first diagonal edge region 900 may have substantially the same structure.

[0145] The cross section 1000 taken along the eighth cutting plane line II′ may include the substrate 270 , the anti-reflection layer 275 , the photoelectric conversion element 280 , the isolation film 290 , the metal layer 230 , the air layer 240 , the color filter 300 , the overcoat layer 310 , and the microlens 320 .

[0146] In some implementations, the structure, function, and materials of the components included in cross section 1000 are similar to those of reference Figure 5 The structure, function and materials of the components described in cross section 500 are substantially the same as those of Figure 5 The structure is different. For the convenience of description, Fig.10 The first cover film 250 and the second cover film 260 are omitted. Figure 5 The same approach includes a first cover film 250 and a second cover film 260 .

[0147] Similar to Figure 8 In the structure shown, the main light is obliquely incident on the top surface of the first layer in the first diagonal edge area 900. Therefore, in the cross section 1000, the second layer may be shifted relative to the first layer, and the third layer may be shifted relative to the second layer, so that the main light that has passed through the microlens 320 of the fifth pixel P5 passes through the color filter 300 of the fifth pixel P5 and is incident on the photoelectric conversion element 280 of the fifth pixel P5. The distance by which the second layer is shifted relative to the first layer and the distance by which the third layer is shifted relative to the second layer can be determined experimentally to minimize crosstalk between pixels while maximizing light receiving efficiency. In addition, the distance by which the second layer is shifted relative to the first layer and the distance by which the third layer is shifted relative to the second layer may be equal to or different from each other.

[0148] In the region disposed between the first diagonal edge region 900 and the central region CT, a distance by which the second layer is shifted relative to the first layer and a distance by which the third layer is shifted relative to the second layer may gradually increase from the central region CT toward the first diagonal edge region 900. This is because the incident angle of the chief light increases from the central region CT toward the first diagonal edge region 900.

[0149] In the present patent document, the main ray effectively incident on the fifth pixel P5 may have a range from the fourth ray L4 to the sixth ray L6. When the main ray is effectively incident, it may indicate that the main ray is incident on the photoelectric conversion element 280 of the fifth pixel P5.

[0150] The fourth light L4 may be incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0151] The fifth light L5 may be incident on the color filter 300 , reflected by the metal layer 230 (more specifically, the first and second cover films 250 and 260 covering the metal layer 230 ), and incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0152] The sixth light L6 may be incident on the color filter 300 , reflected by the air layer 240 , and incident on the photoelectric conversion element 280 through the color filter 300 , the anti-reflection layer 275 , and the substrate 270 .

[0153] The sixth light ray L6 as the outermost light on one side (i.e., the left side) among the main light rays effectively guided toward the fifth pixel P5 may be reflected by the air layer 240 disposed on the left side of the color filter 300 and incident on the photoelectric conversion element 280 of the fifth pixel P5. In addition, the fourth light ray L4 as the outermost light on the other side (i.e., the right side) among the main light rays effectively guided toward the fifth pixel P5 may be incident through the microlens 320 of the fifth pixel P5 and incident on the photoelectric conversion element 280 of the fifth pixel P5 through the opening defined by the air layer 240 disposed on the right side of the color filter 300.

[0154] Therefore, the range of the main light effectively incident on the fifth pixel P5 can be determined based on the opening defined by the air layer 240 disposed on both sides of the fifth pixel P5 in the direction of the main light. In other words, the main light effectively guided toward the fifth pixel P5 can interact with the air layer 240. This is because the air layer 240 is disposed in the propagation direction of the main light.

[0155] exist Fig. 9 and Fig.10, the first diagonal edge region 900 is described as an example. However, except that the second layer and the third layer are shifted in different directions according to the direction of the main light, substantially the same technical concept can be applied to the second diagonal edge region DRD, the third diagonal edge region DLD and the fourth diagonal edge region DRU. That is, the range of the main light effectively guided toward each pixel in the second diagonal edge region DRD, the third diagonal edge region DLD and the fourth diagonal edge region DRU can be determined by the opening defined by the air layer 240 set on both sides of each pixel in the direction of the main light.

[0156] This indicates the range of primary rays that are effectively directed toward each pixel in the diagonal edge region and the range of primary rays that are effectively directed toward the reference pixel. Figure 8 The range of the main light directed by each pixel in the horizontal edge region or the vertical edge region described is substantially the same. In addition, in the diagonal edge region and the horizontal edge region or the vertical edge region, the range of the main light effectively incident on each pixel can be substantially the same as the range of the main light incident on the microlens 320 of each pixel.

[0157] Even in the central region CT, the range of the main light effectively incident on each pixel is substantially the same as the range of the main light incident on the microlens 320 of each pixel. This is because the incident angle of the main light corresponds to 0° (or an angle approximately equal to 0°). In addition, the range of the main light effectively guided toward each pixel in the central region CT can be determined based on the opening defined by the air layer 240 disposed on both sides of each pixel in the direction of the main light.

[0158] Therefore, since the shape and position of the air layer of each pixel are changed according to the direction of the main light relative to the pixel while the air layer of the pixel is individually set, optical uniformity across the entire pixel array 110 can be guaranteed.

[0159] and Fig. 9 and Fig.10 Unlike the embodiment of the present invention, it is assumed that the first grid structure 210 in the entire pixel array 110 has the same position and shape. That is, it is assumed that the first grid structure 210 is set even in the first diagonal edge area VLU. Figure 7 A first grid structure 210 is shown.

[0160] In this case, with Fig.10 Different from the cross-section of FIG. 2 , the cross-section taken along the eighth cutting plane line II′ may not include the air layer 240 .

[0161] Therefore, the main light effectively guided toward the fifth pixel P5 may have a range from the fifth light L5 to the seventh light L7 instead of a range from the fourth light L4 to the sixth light L6.

[0162] That is, when there is no air layer 240, the sixth light ray L6' may be incident on the color filter 300 of the fifth pixel P5, may pass through the area corresponding to the air layer 240, and may be guided toward the photoelectric conversion element 280 of the first pixel P1 through the color filter 300, the anti-reflection layer 275, and the substrate 270 of the first pixel P1. This indicates that the sixth light ray L6' becomes the main light ray effectively guided toward the first pixel P1, rather than the main light ray effectively guided toward the fifth pixel P5.

[0163] When there is no air layer 240, the seventh light ray L7 may be incident on the color filter 300 of the ninth pixel P9 through the microlens 320 of the ninth pixel P9, may pass through the area corresponding to the air layer 240, and may be guided toward the photoelectric conversion element 280 of the fifth pixel P5 through the color filter 300, the anti-reflection layer 275, and the substrate 270 of the fifth pixel P5. This indicates that the seventh light ray L7 becomes the main light ray effectively guided toward the fifth pixel P5, rather than the main light ray effectively guided toward the ninth pixel P9.

[0164] That is, based on the above comparison, the range of the main light effectively guided toward the fifth pixel P5 can be determined by the opening defined by the metal layer 230 disposed on both sides of the fifth pixel P5 in the direction of the main light. In other words, the main light effectively guided toward the fifth pixel P5 can interact with the metal layer 230. This is because the air layer 240 is not disposed in the propagation direction of the main light.

[0165] In this case, as described above, the range of effectively incident principal rays may be different from the case where the air layer 240 is provided, and the optical uniformity across the entire pixel array 110 may be degraded. For an image generated from the pixel array 110, the degradation of the optical uniformity of the pixel array 110 may become serious noise.

[0166] Fig.11 is a schematic diagram showing the Figure 2 FIG. 1 is a diagram of an example of a first grid structure having different shapes depending on the position of a pixel array.

[0167] Fig.11 The first horizontal edge region HL, the region between the first horizontal edge region HL and the first diagonal edge region DLU, and the position and shape of the first grid structure 210 in the first diagonal edge region DLU are shown. Fig.11 , the intersection point CP may correspond to an intersection between a horizontal line passing through a center of the first grid structure 210 disposed on an upper side of the fifth pixel P5 and a vertical line passing through a center of the first grid structure 210 disposed on a left side of the fifth pixel P5.

[0168] exist Fig.11In the left first horizontal edge region HL, the first grid structure 210 disposed on the upper side of the fifth pixel P5 may be spaced apart from the intersection CP by a first distance D1. The first grid structure 210 disposed on the left side of the fifth pixel P5 may be spaced apart from the intersection CP by a second distance D2.

[0169] exist Fig.11 In the region between the central first horizontal edge region HL and the first diagonal edge region DLU, the first grid structure 210 disposed on the upper side of the fifth pixel P5 may be spaced apart from the intersection CP by a third distance D3. The first grid structure 210 disposed on the left side of the fifth pixel P5 may be spaced apart from the intersection CP by a fourth distance D4. The third distance D3 may be smaller than the first distance D1, and the fourth distance D4 may be smaller than the second distance D2.

[0170] From the first horizontal edge area HL toward the first diagonal edge area DLU, the direction of the main light may gradually change from the left side toward the upper left. In this case, the first grid structure 210 disposed on the upper side of the fifth pixel P5 and the first grid structure 210 disposed on the left side of the fifth pixel P5 may be gradually moved to be disposed close to the intersection CP, so that the range of the main light effectively guided toward the fifth pixel P5 may be determined by the opening defined by the air layer 240 disposed on both sides of the fifth pixel P5 in the direction of the main light, or optical uniformity may be maintained.

[0171] According to an embodiment, as the first grid structure 210 disposed on the upper side of the fifth pixel P5 and the first grid structure 210 disposed on the left side of the fifth pixel P5 gradually move to be disposed close to the intersection CP, the length of the first grid structure 210 disposed on the upper side of the fifth pixel P5 and the length of the first grid structure 210 disposed on the left side of the fifth pixel P5 may be reduced. This is to omit the first grid structure 210 corresponding to the area not related to the main light as the direction of the main light gradually changes from the left side toward the upper left. In addition, as the length of the first grid structure 210 is reduced, the volume of the air layer 240 may be reduced to further prevent bursting at the weak point.

[0172] From the first horizontal edge region HL toward the first diagonal edge region DLU, the third distance D and the fourth distance D4 may gradually decrease. Fig.11 In the right first horizontal edge region HL, the first grid structure 210 disposed on the upper side of the fifth pixel P5 and the first grid structure 210 disposed on the left side of the fifth pixel P5 may be merged to have a curved shape such as an L shape to cover the upper left vertex.

[0173] After the first grid structure 210 is merged to have a curved shape such as an L shape, the entire length of the first grid structure 210 may be reduced as the position of the pixel within the first diagonal edge area DLU approaches the upper left vertex of the pixel array 110. This is because, since the direction of the main light approaches the upper left vertex of the corresponding pixel as the position of the pixel becomes closer to the upper left vertex of the pixel array 110, optical uniformity may be maintained even if the entire length of the first grid structure 210 is reduced. In addition, as the entire length of the first grid structure 210 is reduced, the volume of the air layer 240 may be reduced to further prevent bursting at a weak point.

[0174] exist Fig.11 , the shape and position of the first grid structure 210 in the region between the first horizontal edge region HL and the first diagonal edge region DLU have been described. However, the same technical concept can be applied to the first grid structure 210 disposed in a random horizontal edge region or vertical edge region and in a region between diagonal edge regions on the left / right side or upper / lower side thereof.

[0175] For example, the first grid structure 210 in the second vertical edge region VD may be Fig.11 The first grid structures 210 in the first horizontal edge region HL are substantially the same. From the second vertical edge region VD toward the second diagonal edge region DRD, the first grid structures 210 disposed on the lower and right sides of each pixel may gradually move to be disposed close to each other. In the second diagonal edge region DRD, the first grid structure 210 may have a curved shape such as an L shape to cover the lower right vertex.

[0176] That is, from the first region (any one of the first horizontal edge region HL, the second horizontal edge region HR, the first vertical edge region VU, and the second vertical edge region VD) toward the diagonal edge region adjacent to the first region, the position of the first grid structure 210 may become gradually close to the vertex of the L-shaped first grid structure included in the diagonal edge region adjacent to the first region.

[0177] exist Fig.11 In the embodiment of the present invention, it has been described that the shape and position of the first grid structure 210 are changed from the horizontal edge region or the vertical edge region toward the diagonal edge region. However, the shape and position of the first grid structure 210 may be similarly changed from the central region CT toward the diagonal edge region. This is to gradually increase the incident angle of the main light so that the range of the main light effectively guided toward each pixel can be determined by the opening defined by the air layer 240 provided on both sides of the pixel in the direction of the main light, or to maintain optical uniformity.

[0178] For example, the first grid structure 210 in the central region CT may be Fig.11The first grid structures 210 in the first horizontal edge region HL are substantially the same. From the central region CT toward the third diagonal edge region DLD, the first grid structures 210 disposed on the lower and left sides of each pixel may be gradually moved to be disposed close to each other. In the third diagonal edge region DLD, the first grid structure 210 may have a curved shape such as an L shape to cover the lower left vertex.

[0179] Therefore, the position and shape of the first grid structure 210 covering the random pixels included in the pixel array 110 may be determined by the direction and incident angle of the main light incident on the pixel.

[0180] The first to fourth diagonal edge regions DLU, DRD, DLD, and DRU correspond to regions where the direction of the main light corresponds to the first diagonal direction or the second diagonal direction, and the incident angle of the main light is relatively large. As the direction of the main light approaches the first diagonal direction or the second diagonal direction and the incident angle of the main light increases, the position and shape of the first grid structure 210 covering the random pixels may be similar to the position and shape of the first grid structure 210 of the closest diagonal edge region among the first to fourth diagonal edge regions DLU, DRD, DLD, and DRU.

[0181] Based on this embodiment, the first grid structures 210 implemented independently of each other may be disposed on both sides of the pixel abutting against the first grid structure 210 along the direction of the main light incident on the pixel, thereby providing optical uniformity of the pixel array 110 .

[0182] In the present patent document, description has been made by taking the single first grid structure 210 including the air layer 240 as an example. However, the technical concept of the present patent document may be applied to a random separation type grid structure.

[0183] Although various embodiments are described above as specific examples for implementing those embodiments, variations and modifications of those embodiments and other embodiments may be made based on what is disclosed and shown in this patent document.

[0184] CROSS-REFERENCE TO RELATED APPLICATIONS

[0185] This application claims priority to and the benefit of Korean Application No. 10-2020-0062225, filed on May 25, 2020, which is hereby incorporated by reference in its entirety as a part of the disclosure of this patent document.

Claims

1. An image sensing device, comprising: an image sensing pixel array comprising a plurality of image sensing pixels operable to respond to light and generate imaging pixel signals; as well as a first grid structure, the first grid structure being disposed between a plurality of image sensing pixels to separate adjacent image sensing pixels, and the length of the first grid structure being smaller than the length of each side of the image sensing pixel, The image sensing pixel array is configured to include a central region located at or near the center of the image sensing pixel array, a first diagonal edge region and a second diagonal edge region disposed on opposite sides of the central region in a first diagonal direction, and a third diagonal edge region and a fourth diagonal edge region disposed on opposite sides of the central region in a second diagonal direction different from the first diagonal direction. wherein the first grid structure includes a bent portion in at least one of the first diagonal edge region, the second diagonal edge region, the third diagonal edge region, and the fourth diagonal edge region to cover one vertex and an adjacent portion of each image sensing pixel to separate the imaging pixel from an adjacent image sensing pixel, The first grid structure includes a low refractive index layer having a refractive index lower than that of the surrounding environment, wherein the first grid structure comprises an L-shaped structure disposed at a vertex of the image sensing pixel, The central area further includes a second grid structure disposed between the first grid structures to physically isolate the first grid structures from each other. The plurality of first grid structures located in the central area are symmetrically located on four sides of each image sensing pixel, and In each of the first to fourth diagonal edge regions, the L-shaped structure covers a vertex of each image sensing pixel that is farthest from the central region and a portion of adjacent sides of the vertex.

2. The image sensing device according to claim 1, wherein: The low refractive index layer includes a structure filled with air.

3. The image sensing device according to claim 1, wherein: The second grid structure includes a layer of material different from that of the low refractive index layer.

4. The image sensing device according to claim 1, wherein: A length of each of the first grid structures in the central region is smaller than a length of a corresponding side of the image sensing pixel.

5. The image sensing device according to claim 1, wherein: The first grid structure further includes a first capping film configured to cover the low refractive index layer.

6. The image sensing device according to claim 5, wherein: The refractive index of the first capping film is higher than the refractive index of the low refractive index layer and lower than the refractive index of the color filter abutting the first grid structure.

7. The image sensing device according to claim 5, wherein: The first grid structure further includes a second covering film configured to cover the first covering film and having a thickness greater than that of the first covering film.

8. The image sensing device according to claim 5, wherein: The first grid structure further includes a metal layer disposed below the low refractive index layer and formed of metal.

9. The image sensing device according to claim 1, wherein: The direction from the center of the image sensing pixel toward the vertex of the image sensing pixel surrounded by the first grid structure corresponds to the direction from the central area toward the diagonal edge area including the image sensing pixel among the first diagonal edge area, the second diagonal edge area, the third diagonal edge area and the fourth diagonal edge area.

10. The image sensing device according to claim 9, wherein: The first diagonal edge region is disposed at a first side of the central region and includes an L-shaped first grid structure disposed at a first vertex of the image sensing pixel corresponding to the first side of the central region.

11. The image sensing device according to claim 9, wherein: The second diagonal edge region is disposed at a second side of the central region and includes an L-shaped first grid structure disposed at a second vertex of the image sensing pixel corresponding to the second side of the central region.

12. The image sensing device according to claim 9, wherein: The third diagonal edge region is disposed at a third side of the central region and includes an L-shaped first grid structure disposed at a third vertex of the image sensing pixel corresponding to the third side of the central region.

13. The image sensing device according to claim 9, wherein: The fourth diagonal edge region is disposed at a fourth side of the central region and includes an L-shaped first grid structure disposed at a fourth vertex of the image sensing pixel corresponding to the fourth side of the central region.

14. The image sensing device according to claim 1, wherein: The image sensing pixel array further includes a first horizontal edge region and a second horizontal edge region disposed on both sides of the central region along a horizontal line passing through the central region, and a first vertical edge region and a second vertical edge region disposed on both sides of the central region along a vertical line passing through the central region, The shape and position of the first grid structure respectively included in the first horizontal edge region and the second horizontal edge region and the first vertical edge region and the second vertical edge region correspond to the shape and position of the first grid structure included in the central region.

15. The image sensing device according to claim 14, wherein: From any one of the first horizontal edge region, the second horizontal edge region, the first vertical edge region and the second vertical edge region toward a diagonal edge region adjacent to any one of the regions, the position of the first grid structure gradually approaches the vertex where the first grid structure is located in the diagonal edge region adjacent to any one of the regions.

16. An image sensing device, the image sensing device comprising: an image sensing pixel array comprising an array of image sensing pixels to detect incident light to generate pixel signals representative of an image carried by the incident light; an objective lens positioned relative to the image sensing pixel array to receive incident light and direct the incident light to the image sensing pixel array for detection; as well as a plurality of isolation structures, the plurality of isolation structures being disposed between adjacent image sensing pixels of the image sensing pixel array, each isolation structure being configured to include a portion filled with air to provide optical isolation between adjacent image sensing pixels, wherein a plurality of the isolation structures located in the central region of the image sensing pixel array around the optical axis of the objective lens passing through the center of the image sensing pixel array are symmetrically located on four sides of each image sensing pixel, and Among them, the multiple isolation structures located in the peripheral area of ​​the image sensing pixel array away from the optical axis of the objective lens include a curved isolation structure, which covers a vertex of each image sensing pixel farthest from the optical axis of the objective lens and a portion of the adjacent side of the vertex.

17. The image sensing device according to claim 16, wherein: Each insulation structure is constructed to include a hollow section filled with air.

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