Image sensing device

Abstract

The invention relates to an image sensing device. In an embodiment, an image sensing device includes a pixel array in which a plurality of unit pixels are disposed, in which the unit pixels include a plurality of sub-pixels, in which a first isolation region is formed in an edge region of the sub-pixels, and in which a second isolation region is formed from the first isolation region in a direction of a central portion of the sub-pixels, the second isolation region includes a first inner isolation region protruding from one region of the first isolation region in the direction of the central portion of the sub-pixel, and a second inner isolation region formed on the same straight line as the first inner isolation region and protruding from another region of the first isolation region in the direction of the central portion of the sub-pixel, and wherein the third isolation region is formed in an orthogonal direction between the first inner isolation region and the second inner isolation region.

Description

Technical Field

[0001] Various embodiments of the disclosed technology relate to an image sensing device. Background Art

[0002] An image sensing device refers to a semiconductor device that captures an optical image and converts it into an electrical signal. With the development of the automotive, medical, computer, and telecommunications industries, the demand for high-performance image sensing devices in various devices such as smart phones, digital cameras, game devices, the Internet of Things, robots, security cameras, and medical micro-cameras has been increasing.

[0003] The most common types of image sensing devices are charge-coupled device (CCD) image sensing devices and complementary metal oxide semiconductor (CMOS) image sensing devices. Summary of the Invention

[0004] The disclosed technology may be implemented in some embodiments to provide an image sensing device that can improve the Gr / Gb signal difference by forming a light scattering region and at the same time minimize optical loss.

[0005] In an embodiment, an image sensing device may include: a pixel array including a plurality of unit pixels, wherein each unit pixel includes: a plurality of sub-pixels; wherein a first isolation region may be formed in an edge region of the plurality of sub-pixels; wherein a second isolation region may be formed from the first isolation region toward a central portion of each sub-pixel, wherein the second isolation region includes: a first inner isolation region protruding from a region of the first isolation region toward the central portion of the sub-pixel; and a second inner isolation region aligned with the first inner isolation region and protruding from another region of the first isolation region toward the central portion of the sub-pixel; and wherein a third isolation region is formed in a direction orthogonal to the direction in which the first inner isolation region and the second inner isolation region are arranged.

[0006] In an example, each sub-pixel includes: a first isolation region; a second isolation region including a first inner isolation region and a second inner isolation region; an isolation layer formed above the first inner isolation region and the second inner isolation region; a third isolation region formed below the isolation layer; a color filter formed above the isolation layer; and a microlens formed above the color filter.

[0007] In an example, the second inner isolation region is formed at a position spaced apart from the first inner isolation region by a certain distance.

[0008] In an example, the third isolation region is formed in a direction crossing between the first inner isolation region and the second inner isolation region from a side of the first isolation region perpendicular to the first inner isolation region or the second inner isolation region.

[0009] In the example, the third isolation region includes at least one of an oxide, a nitride, or a nitrogen oxide.

[0010] In the example, the third isolation region includes a material different from that of the second isolation region.

[0011] In the example, the second isolation region includes a material having a refractive index higher than that of silicon.

[0012] In the example, the second isolation region includes polysilicon.

[0013] In the example, the third isolation region includes a material having a refractive index lower than that of silicon.

[0014] In the example, the depth of the third isolation region is less than the depth of the second isolation region.

[0015] In the example, the third isolation region is in contact with the second isolation region.

[0016] In the example, the third isolation region is spaced apart from the second isolation region.

[0017] In an embodiment, an image sensing device may include: a pixel array including a plurality of unit pixels, wherein each unit pixel includes: a first sub-pixel including a green color filter; a second sub-pixel including a red color filter; a third sub-pixel including a blue color filter; wherein a first isolation region may be formed in an edge region of the first sub-pixel, wherein a fourth isolation region may be formed in an edge region of the second sub-pixel, wherein a second isolation region may be formed from the first isolation region towards a central portion of the first sub-pixel, wherein a fifth isolation region may be formed to protrude from the fourth isolation region in a direction perpendicular to the direction in which the second isolation region is formed, wherein the second isolation region includes: a first inner isolation region protruding from one region of the first isolation region towards the central portion of the first sub-pixel; and a second inner isolation region aligned with the first inner isolation region and protruding from another region of the first isolation region towards the central portion of the first sub-pixel, wherein the fifth isolation region includes: a third inner isolation region protruding from one region of the fourth isolation region towards the central portion of the second sub-pixel; and a fourth inner isolation region aligned with the third inner isolation region and protruding from another region of the fourth isolation region towards the central portion of the second sub-pixel, wherein the third isolation region may be formed in a direction orthogonal to the direction in which the first inner isolation region and the second inner isolation region are arranged; and wherein a sixth isolation region may be formed in a direction orthogonal to the direction in which the third inner isolation region and the fourth inner isolation region are arranged.

[0018] In the example, the first sub-pixel includes: a first isolation region; a second isolation region including a first inner isolation region and a second inner isolation region; an isolation layer formed over the first isolation region and the second isolation region; a third isolation region formed under the isolation layer; a green color filter formed over the isolation layer; and a microlens formed over the green color filter.

[0019] In the example, the first inner isolation region is formed at a position spaced apart from the second inner isolation region by a certain distance.

[0020] In the example, the third isolation region is formed in a direction crossing between the first inner isolation region and the second inner isolation region from a side of the first isolation region perpendicular to the first inner isolation region or the second inner isolation region.

[0021] In the example, the third isolation region includes at least one of an oxide, a nitride, or a nitrogen oxide.

[0022] In the example, the third inner isolation region is formed at a position spaced apart from the fourth inner isolation region by a certain distance.

[0023] In the example, the sixth isolation region is formed in a direction crossing between the third inner isolation region and the fourth inner isolation region from a side of the fourth isolation region perpendicular to the third inner isolation region or the fourth inner isolation region.

[0024] In the example, the seventh isolation region may be formed in an edge region of the third sub-pixel, the eighth isolation region may be formed to protrude from the seventh isolation region in a direction perpendicular to the direction in which the second isolation region is formed, the eighth isolation region includes: a fifth inner isolation region protruding from one region of the seventh isolation region toward a central portion of the third sub-pixel; and a sixth inner isolation region aligned with the fifth inner isolation region and protruding from another region of the seventh isolation region toward the central portion of the third sub-pixel, and the ninth isolation region may be formed in a direction orthogonal to the direction in which the fifth inner isolation region and the sixth inner isolation region are arranged. Description of the Drawings

[0025] Figure 1 is a block diagram of an image sensing device based on an embodiment.

[0026] Figure 2 is a diagram for describing a pixel array based on an embodiment.

[0027] Figure 3 is a diagram for describing a first sub-pixel of a pixel array based on an embodiment.

[0028] Figure 4 is along Figure 3 a cross-sectional view taken along line A - A' of the first sub-pixel.

[0029] Figure 5 is a cross-sectional view taken along line B-B' of the first sub-pixel of Figure 3 .

[0030] Figure 6 is a diagram for describing a second sub-pixel of a pixel array based on an embodiment.

[0031] Figure 7 is a cross-sectional view taken along line C-C' of the second sub-pixel of Figure 6 .

[0032] Figure 8 is a diagram for describing a third sub-pixel of a pixel array based on an embodiment.

[0033] Figure 9 is a cross-sectional view taken along line D-D' of the third sub-pixel of Figure 8 . DETAILED DESCRIPTION

[0034] Features and certain advantages related to specific implementations of the disclosed technology are described by way of example embodiments with reference to the accompanying drawings.

[0035] The disclosed technology can be implemented in some embodiments to provide an image sensing device capable of improving the signal difference (Gr / Gb) between Gr pixels and Gb pixels. In some implementations, the signal difference (Gr / Gb) indicates the signal difference between green pixels (Gb) in a blue row and green pixels (Gr) in a red row.

[0036] In the case of a dual photodiode (2PD) type image sensing device, light incident on a microlens is scattered by a deep trench isolation region (DTI) and passes through the wall surface of adjacent pixels, acting as crosstalk.

[0037] In the case of the red wavelength, the penetration amount into adjacent pixels is greater than that of the blue wavelength or the green wavelength. Therefore, the signal of the Gr pixel or the Gb pixel can increase according to the 2PD direction of the red pixel.

[0038] According to the 2PD direction of the red pixel, the Gr / Gb signal difference can have a value less than or greater than 1, resulting in degradation. In some implementations, by forming a light scattering region in the direction crossing (or extending) between inner isolation regions, the output signal difference (Gr / Gb) between Gr pixels and Gb pixels of a Bayer pattern can be improved while minimizing light loss. That is, by forming a light scattering region in the direction crossing (or extending) between inner isolation regions, the difference between Gr and Gb can be minimized, such that the Gr / Gb signal difference has a value close to 1.

[0039] Figure 1 is a block diagram of an image sensing device according to an embodiment.

[0040] Referring Figure 1 , an image sensing device according to an embodiment may include a pixel array 1100, a row driver 1200, a correlated double sampler (CDS) 1300, an analog-to-digital converter (ADC) 1400, an output buffer 1500, a column driver 1600, a timing controller 1700, and a bias generator 1800. Figure 1 The components of the image sensing device shown are discussed only by way of example, and the disclosed technology is not limited to Figure 1 the technology shown.

[0041] The pixel array 1100 may include a plurality of pixels arranged in multiple rows and columns. In one embodiment, the plurality of pixels may be arranged in a two-dimensional pixel array including rows and columns. In another example, the plurality of unit imaging pixels may be arranged in a three-dimensional pixel array. The plurality of pixels may detect incident light to capture an image carried by the incident light by converting an optical signal or incident light into an electrical signal based on a unit pixel or a pixel group, and pixels in the pixel group share at least some internal circuits. Such electrical signals generated by different pixels or different pixel groups uniformly represent the image carried in the incident light. The pixel array 1100 may receive drive signals including a row selection signal, a pixel reset signal, and a transfer signal from the row driver 1200. When the drive signals are received, corresponding pixels in the pixel array 1100 may be activated to perform operations corresponding to the row selection signal, the pixel reset signal, and the transfer signal.

[0042] The row driver 1200 may activate the pixel array 1100 based on commands and control signals provided by the timing controller 1700 to perform certain operations on the pixels in the corresponding row. In one embodiment, the row driver 1200 may select at least one pixel arranged in at least one row of the pixel array 1100. The row driver 1200 may generate a row selection signal to select at least one row among a plurality of rows. The row driver 1200 may sequentially enable the pixel reset signal and the transfer signal for the pixels corresponding to at least one selected row. Accordingly, a reference signal and an image signal, which are analog signals generated by each pixel of the selected row, may be sequentially transmitted to the CDS 1300. Here, the reference signal may be an electrical signal provided to the CDS 1300 when a sensing node (e.g., a floating diffusion node) of a pixel is reset, and the image signal may be an electrical signal provided to the CDS 1300 when photo charges generated by the pixel are accumulated in the sensing node. The reference signal representing reset noise inherent in the pixel and the image signal representing the intensity of the incident light may be collectively referred to as pixel signals.

[0043] A CMOS image sensor can use correlated double sampling (CDS) to remove an undesired offset value of a pixel known as fixed pattern noise by sampling the pixel signal twice and removing the difference between the two samplings. In some embodiments, correlated double sampling (CDS) can remove the undesired offset value of a pixel by comparing the pixel output voltages obtained before and after the optical charge generated by a unit pixel in response to incident light is accumulated in a sensing node, such that the pixel output voltage based only on the incident light can be measured. In one embodiment, CDS 1300 can sequentially sample and hold a reference signal and an image signal provided to each of a plurality of column lines from a pixel array 1100. That is, CDS1300 can sample and hold a reference signal and an image signal corresponding to each column of the pixel array 1100.

[0044] CDS1300 can transmit the reference image signal and the image signal of each column to ADC 1400 as a correlated double sampling signal based on a control signal from a timing controller 1700.

[0045] ADC 1400 is used to convert the CDS signal into a digital signal for each column and output the digital signal. In one embodiment, ADC 1400 can be implemented as a ramp comparison type ADC. The ramp comparison type ADC can include a comparator circuit for comparing an analog pixel signal with a ramp signal that ramps up or down over time and a counter for counting until the ramp signal matches the analog pixel signal. In one embodiment, ADC 1400 can convert the correlated double sampling signal generated by CDS1300 for each column into a digital signal and output the digital signal.

[0046] ADC 1400 can include a plurality of column counters corresponding to each column of the pixel array 1100. Each column of the pixel array 1100 is coupled to a column counter, and image data can be generated by converting the correlated double sampling signal corresponding to each column into a digital signal using the column counter. In another embodiment, ADC 1400 can include a global counter to convert the correlated double sampling signal corresponding to each column into a digital signal using a global code provided from the global counter.

[0047] Output buffer 1500 can temporarily hold column-based image data provided from ADC 1400 to output the image data. Output buffer 1500 can temporarily store the image data output from ADC 1400 based on a control signal from timing controller 1700. Output buffer 1500 can be used as an interface to compensate for a data rate difference or a transmission (or processing) rate difference between the image sensing device and other devices.

[0048] The column driver 1600 can select columns of the output buffer 1500 based on control signals from the timing controller 1700, and sequentially output the image data temporarily stored in the selected columns of the output buffer 1500. In one embodiment, when receiving an address signal from the timing controller 1700, the column driver 1600 can generate a column selection signal based on the address signal and select columns of the output buffer 1500, and output the image data from the selected columns of the output buffer 1500 as an output signal.

[0049] The timing controller 1700 can control at least one of the line driver 1200, the CDS 1300, the ADC 1400, the output buffer 1500, the column driver 1600, or the bias generator 1800.

[0050] The timing controller 1700 can provide a clock signal required for the operation of the corresponding components of the image sensing device, a control signal for timing control, an address signal for selecting a row or a column, a signal for controlling the level of the bias voltage applied to the pixel array 1100, etc. to at least one of the line driver 1200, the CDS 1300, the ADC 1400, the output buffer 1500, the column driver 1600, or the bias generator 1800. In an embodiment of the present disclosure, the timing controller 1700 can include a logic control circuit, a phase-locked loop (PLL) circuit, a timing control circuit, a communication interface circuit, etc.

[0051] The bias generator 1800 can generate a bias voltage for suppressing the dark current generated in the pixels of the pixel array 1100 and supply the generated bias voltage to the pixel array 1100.

[0052] The bias voltage can be determined and stored in a one-time programmable (OTP) memory during the wafer probe test of the image sensing device. For example, the bias voltage can be experimentally determined as a value that can maximize the dark current suppression effect while minimizing unnecessary power consumption without degrading the performance of the image sensing device.

[0053] The bias generator 1800 can generate a voltage corresponding to the bias voltage stored in the OTP memory. In an embodiment, the OTP memory can be included in the image sensing device, and specifically, can be included in the bias generator 1800.

[0054] In an embodiment, the bias voltage can be one of multiple values.

[0055] For example, multiple values can respectively correspond to multiple operation modes of the image sensing device. The dark current generated in low light and the dark current generated in high light can be different from each other, and the bias voltage provided by the bias generator 1800 to effectively suppress the dark current in each environment can vary according to the mode.

[0056] In some implementations, multiple values can respectively correspond to multiple regions of the pixel array 1100. The generated dark current can be different from each other according to the positions of the pixels in the pixel array 1100, and the bias voltage provided by the bias generator 1800 to effectively suppress the dark current regardless of the positions of the pixels can vary according to the regions.

[0057] The bias voltage can be a negative voltage with a negative sign, but the present disclosure is not limited thereto.

[0058] Figure 2 is a diagram for describing a pixel array based on an embodiment. Figure 3 is a diagram for describing a first sub-pixel of a pixel array based on an embodiment.

[0059] Referring to Figure 2 , the image sensing device based on the embodiment can be a dual photodiode (2PD) type image sensing device.

[0060] In an embodiment, the pixel array 1100 can include multiple unit pixels (or unit image sensing pixels), and each unit pixel can include: a first sub-pixel 300 including a green color filter to generate a first sub-pixel signal associated with the detected green light, a second sub-pixel 400 including a red color filter to generate a second sub-pixel signal associated with the detected red light, and a third sub-pixel 500 including a blue color filter to generate a third sub-pixel signal associated with the detected blue light. For example, each unit pixel can include a combination of two first sub-pixels 300, one second sub-pixel 400, and one third sub-pixel 500. The sub-pixel signal generated by the sub-pixel is associated with the unit pixel signal generated by the unit pixel where the sub-pixel is located. In some implementations, the term "pixel" can be used to indicate an image sensing pixel or an image sensor pixel that is a photosensitive element in the image sensing device.

[0061] In some embodiments, each unit pixel can include four sub-pixels. In one example, each sub-pixel can include a color filter of the same color. In one example, two photodiodes can be formed under each color filter.

[0062] Referring to Figure 2 and Figure 3, the first isolation region 310 may be formed in the edge region of the first sub-pixel 300 (e.g., the boundary region between the first sub-pixels 300). The first isolation region 310 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent first sub-pixels 300, and may be formed by a deep trench isolation (DTI) process.

[0063] The first isolation region 310 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0064] The second isolation region 320 may be formed inside the first isolation region 310. The second isolation region 320 may be formed from the first isolation region 310 toward the central portion of the first sub-pixel 300.

[0065] The second isolation region 320 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent photodiodes, and may be formed by a deep trench isolation (DTI) process.

[0066] The second isolation region 320 may include the same material as that of the first isolation region 310.

[0067] The second isolation region 320 may include a material having a refractive index higher than that of silicon (Si).

[0068] The second isolation region 320 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0069] In an embodiment, the second isolation region 320 may include a first inner isolation region 321 and a second inner isolation region 322.

[0070] The first inner isolation region 321 may protrude from a region of the first isolation region 310 toward the central portion of the first sub-pixel 300.

[0071] The second inner isolation region 322 may be aligned with the first inner isolation region 321 (e.g., formed on the same straight line as the first inner isolation region 321), and may protrude from another region of the first isolation region 310 (the region opposite to the region where the first inner isolation region 321 is formed) toward the central portion of the first sub-pixel 300.

[0072] In an embodiment, the first inner isolation region 321 may be formed at a position spaced apart from the second inner isolation region 322 by a certain distance.

[0073] The third isolation region 330 may be formed between the first inner isolation region 321 and the second inner isolation region 322.

[0074] The third isolation region 330 may be formed in a direction orthogonal to the direction in which the first inner isolation region 321 and the second inner isolation region 322 are disposed.

[0075] In some implementations, one end of the third isolation region 330 is connected to one side of the first isolation region 310, and the other end of the third isolation region 330 is connected to the opposite side of one side of the first isolation region 310.

[0076] The third isolation region 330 may include a material different from that of the second isolation region 320.

[0077] The third isolation region 330 may include a material having a refractive index lower than that of silicon (Si).

[0078] In an embodiment, the third isolation region 330 may include an oxide.

[0079] In an embodiment, the third isolation region 330 may include at least one of an oxide, a nitride, or a nitroxide.

[0080] The third isolation region 330 may have a depth different from that of the second isolation region 320.

[0081] The depth of the third isolation region 330 may be less than the depth of the second isolation region 320.

[0082] In an embodiment, an oxide layer (not shown) may be formed on the sidewalls of the second isolation region 320. In one example, the third isolation region 330 may be in contact with the oxide layer (not shown) of the second isolation region 320. In another example, the third isolation region 330 may be spaced apart from the oxide layer (not shown) of the second isolation region 320.

[0083] Figure 4 is a cross-sectional view taken along line A-A' of the first sub-pixel Figure 3 Figure 5 is a cross-sectional view taken along line B-B' of the first sub-pixel Figure 3

[0084] Referring to Figure 4 and Figure 5 , the first sub-pixel 300 may include a first isolation region 310, a first inner isolation region 321, a second inner isolation region 322, a third isolation region 330, a green color filter 340, a photodiode 350, a color filter layer isolation region 360, a microlens 370, a substrate 380, and an isolation layer 390. ​​

[0085] The first isolation region 310 may be formed between adjacent first sub-pixels 300.

[0086] The first inner isolation region 321 and the second inner isolation region 322 may be formed under the isolation layer 390.

[0087] In an embodiment, the third isolation region 330 may be formed under the isolation layer 390 and may include a region where at least one of an oxide, a nitride, or a nitrogen oxide is formed (e.g., deposited) in a groove in the etched region of the substrate 380. In an embodiment, the third isolation region 330 may be formed with a thin thickness on the surface of the substrate 380.

[0088] In an embodiment, the third isolation region 330 may be formed in a direction that crosses (or extends) between the first inner isolation region 321 and the second inner isolation region 322 from a side of the first isolation region 310 perpendicular to the first inner isolation region 321 or the second inner isolation region 322. In an embodiment, the first inner isolation region 321, the second inner isolation region 322, and the third isolation region 330 may form a cross structure.

[0089] Since the third isolation region 330 with a thin thickness is formed in a direction that crosses (or extends) between the first inner isolation region 321 and the second inner isolation region 322, scattered light can be dispersed in two directions (up and down, and left and right) instead of being dispersed in one direction (up and down, or left and right), and thus the output signal (Gr / Gb) difference between the Gr pixel and the Gb pixel of the Bayer pattern can be improved. In addition, compared with the pixel isolation region of the cross structure (DTI), optical loss can be minimized and the Gr / Gb signal difference can be improved. In the case of the pixel isolation region of the cross structure (DTI), optical loss may occur due to optical absorption.

[0090] The green color filter 340 may be formed above the isolation layer 390. The green color filter 340 may filter and transmit visible light in the incident light incident on the microlens 370 and may allow only green light in the visible light to pass through.

[0091] The photodiode 350 may be formed in the inner region of the substrate 380 and may be formed under the third isolation region 330, and an n-type impurity region and a p-type impurity region may be vertically stacked in the photodiode 350. The n-type impurity region and the p-type impurity region may be formed by an ion implantation process.

[0092] The color filter layer isolation region 360 may be formed above the first isolation region 310.

[0093] The microlens 370 may be formed above the green color filter 340 and may be used to collect incident light entering from the outside.

[0094] In an embodiment, the substrate 380 may include a silicon (Si) material in a single crystal state.

[0095] The isolation layer 390 may be formed above the first isolation region 310 and the second isolation region 320 and may include at least one of an oxide, a nitride, or a nitrogen oxide.

[0096] Figure 6 It is a diagram for describing a second sub-pixel of a pixel array based on an embodiment.

[0097] Referring to Figure 2 and Figure 6 , the fourth isolation region 410 may be formed in an edge region (a boundary region between the second sub-pixels 400) of the second sub-pixel 400. The fourth isolation region 410 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent sub-pixels and may be formed by a deep trench isolation (DTI) process.

[0098] The fourth isolation region 410 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0099] The fifth isolation region 420 may be formed inside the fourth isolation region 410. The fifth isolation region 420 may be formed from the fourth isolation region 410 toward the central portion of the second sub-pixel 400.

[0100] The fifth isolation region 420 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent photodiodes and may be formed by a deep trench isolation (DTI) process.

[0101] The fifth isolation region 420 may include the same material as that of the fourth isolation region 410.

[0102] The fifth isolation region 420 may include a material having a refractive index higher than that of silicon (Si).

[0103] The fifth isolation region 420 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0104] In an embodiment, the fifth isolation region 420 may include a third inner isolation region 421 and a fourth inner isolation region 422.

[0105] The third inner isolation region 421 may protrude from a region of the fourth isolation region 410 toward the central portion of the second sub-pixel 400.

[0106] The fourth inner isolation region 422 may be aligned with the third inner isolation region 421 (e.g., formed on the same straight line as the third inner isolation region 421), and may protrude from another region of the fourth isolation region 410 (a region opposite to the region where the third inner isolation region 421 is formed) toward the central portion of the second sub-pixel 400.

[0107] In an embodiment, the third inner isolation region 421 may be formed at a position spaced apart from the fourth inner isolation region 422 by a certain distance.

[0108] The sixth isolation region 430 may be formed between the third inner isolation region 421 and the fourth inner isolation region 422.

[0109] The sixth isolation region 430 may be formed in a direction orthogonal to the direction in which the third inner isolation region 421 and the fourth inner isolation region 422 are arranged.

[0110] In some implementations, one end of the sixth isolation region 430 is connected to one side of the fourth isolation region 410, and the other end of the sixth isolation region 430 is connected to the opposite side of one side of the fourth isolation region 410.

[0111] The sixth isolation region 430 may include a material different from that of the fifth isolation region 420.

[0112] The sixth isolation region 430 may include a material having a refractive index lower than that of silicon (Si).

[0113] In an embodiment, the sixth isolation region 430 may include an oxide.

[0114] In an embodiment, the sixth isolation region 430 may include at least one of an oxide, a nitride, or a nitrogen oxide.

[0115] The sixth isolation region 430 may have a depth different from that of the fifth isolation region 420.

[0116] The depth of the sixth isolation region 430 may be less than the depth of the fifth isolation region 420.

[0117] In an embodiment, an oxide layer (not shown) may be formed on the sidewalls of the fifth isolation region 420, and the sixth isolation region 430 may be formed to contact the oxide layer (not shown) of the fifth isolation region 420 or be spaced apart from the oxide layer (not shown) of the fifth isolation region 420.

[0118] Figure 7 is a cross-sectional view taken along line C-C' of the second sub-pixel of Figure 6 .

[0119] Referring to Figure 6 and Figure 7 , the second sub-pixel 400 may include a fourth isolation region 410, a third inner isolation region 421, a fourth inner isolation region 422, a sixth isolation region 430, a red color filter 440, a photodiode 450, a color filter layer isolation region 460, a microlens 470, a substrate 480, and an isolation layer 490.

[0120] The fourth isolation region 410 may be formed between adjacent sub-pixels.

[0121] The third inner isolation region 421 and the fourth inner isolation region 422 may be formed under the isolation layer 490.

[0122] In an embodiment, the sixth isolation region 430 may be formed under the isolation layer 490 and may be a region where at least one of an oxide, a nitride, or a nitrogen oxide is formed (e.g., deposited) in a groove in an etched region of the substrate 480. In an embodiment, the sixth isolation region 430 may be formed with a thin thickness on the surface of the substrate 480.

[0123] In an embodiment, the sixth isolation region 430 may be formed in a direction that crosses (or extends) between the third inner isolation region 421 and the fourth inner isolation region 422 from a side of the fourth isolation region 410 perpendicular to the third inner isolation region 421 or the fourth inner isolation region 422. In an embodiment, the third inner isolation region 421, the fourth inner isolation region 422, and the sixth isolation region 430 may form a cross structure.

[0124] Since the sixth isolation region 430 having a thin thickness is formed in a direction that crosses (or extends) between the third inner isolation region 421 and the fourth inner isolation region 422, scattered light can be dispersed in two directions (up and down, and left and right directions) instead of being dispersed in one direction (up and down, or left and right directions), and thus the output signal (Gr / Gb) difference between the Gr pixel and the Gb pixel can be improved. In addition, compared with the pixel isolation region of the cross structure (DTI), optical loss can be minimized and the Gr / Gb signal difference can be improved. In the case of the pixel isolation region of the cross structure (DTI), optical loss may occur due to optical absorption.

[0125] The sixth isolation region 430 of the second sub-pixel 400 including the red color filter 440 may be formed in a direction perpendicular to the direction in which the third isolation region 330 of the first sub-pixel 300 is formed.

[0126] The red color filter 440 may be formed over the isolation layer 490. The red color filter 440 may filter and transmit visible light in the incident light incident on the microlens 470, and may allow only red light in the visible light to pass through.

[0127] The photodiode 450 may be formed in the inner region of the substrate 480 and may be formed under the sixth isolation region 430, and the n-type impurity region and the p-type impurity region may be vertically stacked in the photodiode 450. The n-type impurity region and the p-type impurity region may be formed by an ion implantation process.

[0128] The color filter layer isolation region 460 may be formed over the fourth isolation region 410.

[0129] The microlens 470 may be formed over the red color filter 440, and may be used to collect incident light entering from the outside.

[0130] In an embodiment, the substrate 480 may include a silicon (Si) material in a single crystal state.

[0131] The isolation layer 490 may be formed over the fourth isolation region 410 and the fifth isolation region 420, and may include at least one of an oxide, a nitride, or a oxynitride.

[0132] Figure 8 It is a diagram for describing a third sub-pixel of a pixel array based on an embodiment.

[0133] Referring to Figure 2 and Figure 8 , the seventh isolation region 510 may be formed in the edge region (the boundary region between the third sub-pixels 500) of the third sub-pixel 500. The seventh isolation region 510 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent sub-pixels, and may be formed by a deep trench isolation (DTI) process.

[0134] The seventh isolation region 510 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0135] The eighth isolation region 520 may be formed inside the seventh isolation region 510. The eighth isolation region 520 may be formed from the seventh isolation region 510 in the direction of the central portion of the third sub-pixel 500.

[0136] The eighth isolation region 520 may be formed in a deep recess in the vertical direction to prevent crosstalk between adjacent photodiodes, and may be formed by a deep trench isolation (DTI) process.

[0137] The eighth isolation region 520 may include the same material as that of the seventh isolation region 510.

[0138] The eighth isolation region 520 may include a material having a refractive index higher than that of silicon (Si).

[0139] The eighth isolation region 520 may include at least one of a silicon oxynitride (SiON) layer, a silicon oxide (SiO) layer, a silicon nitride (SiN) layer, or a polysilicon (Poly Si).

[0140] In an embodiment, the eighth isolation region 520 may include a fifth inner isolation region 521 and a sixth inner isolation region 522.

[0141] The fifth inner isolation region 521 may protrude from a region of the seventh isolation region 510 toward the central portion of the third sub-pixel 500.

[0142] The sixth inner isolation region 522 may be aligned with the fifth inner isolation region 521 (e.g., formed on the same straight line as the fifth inner isolation region 521), and may protrude from another region of the seventh isolation region 510 (a region opposite to the region where the fifth inner isolation region 521 is formed) toward the central portion of the third sub-pixel 500.

[0143] In an embodiment, the fifth inner isolation region 521 may be formed at a position spaced apart from the sixth inner isolation region 522 by a certain distance.

[0144] The ninth isolation region 530 may be formed between the fifth inner isolation region 521 and the sixth inner isolation region 522.

[0145] The ninth isolation region 530 may be formed in a direction orthogonal to the direction between the fifth inner isolation region 521 and the sixth inner isolation region 522.

[0146] It may be configured such that one side of the ninth isolation region 530 contacts one side of the seventh isolation region 510, and the other side of the ninth isolation region 530 contacts the other side of the seventh isolation region 510.

[0147] The ninth isolation region 530 may include a material different from that of the eighth isolation region 520.

[0148] The ninth isolation region 530 may include a material having a refractive index lower than that of silicon (Si).

[0149] In an embodiment, the ninth isolation region 530 may include an oxide.

[0150] In an embodiment, the ninth isolation region 530 may include at least one of an oxide, a nitride, or a nitrogen oxide.

[0151] The ninth isolation region 530 may have a depth different from that of the eighth isolation region 520.

[0152] The depth of the ninth isolation region 530 may be less than the depth of the eighth isolation region 520.

[0153] In an embodiment, an oxide layer (not shown) may be formed on the sidewalls of the eighth isolation region 520. In one example, the ninth isolation region 530 may be in contact with the oxide layer (not shown) of the eighth isolation region 520. In another example, the ninth isolation region 530 may be spaced apart from the oxide layer (not shown) of the eighth isolation region 520.

[0154] Figure 9 is a cross-sectional view taken along line D-D' of the third sub-pixel Figure 8 as shown.

[0155] Referring to Figure 9 , the third sub-pixel 500 may include a seventh isolation region 510, a fifth inner isolation region 521, a sixth inner isolation region 522, a ninth isolation region 530, a blue color filter 540, a photodiode 550, a color filter layer isolation region 560, a microlens 570, a substrate 580, and an isolation layer 590.

[0156] The seventh isolation region 510 may be formed between adjacent sub-pixels.

[0157] The fifth inner isolation region 521 and the sixth inner isolation region 522 may be formed under the isolation layer 590.

[0158] In an embodiment, the ninth isolation region 530 may be formed under the isolation layer 590 and may be a region in a groove where at least one of an oxide, a nitride, or a nitrogen oxide is deposited in an etched region of the substrate 580. In an embodiment, the ninth isolation region 530 may be formed with a thin thickness on the surface of the substrate 580.

[0159] In an embodiment, the ninth isolation region 530 may be formed in a direction crossing (or extending) between the fifth inner isolation region 521 and the sixth inner isolation region 522 from a side of the seventh isolation region 510 perpendicular to the fifth inner isolation region 521 or the sixth inner isolation region 522. In an embodiment, the fifth inner isolation region 521, the sixth inner isolation region 522, and the ninth isolation region 530 may form an intersecting structure.

[0160] Since the ninth isolation region 530 with a thin thickness is formed in the direction where the fifth inner isolation region 521 intersects (or extends) with the sixth inner isolation region 522, scattered light can be dispersed in two directions (upward and downward, and left and right directions) instead of being dispersed in one direction (upward and downward, or left and right directions). Thus, the output signal (Gr / Gb) difference between the Gr pixel and the Gb pixel can be improved. Additionally, compared with the pixel isolation region of the cross structure (DTI), optical loss can be minimized and the Gr / Gb signal difference can be improved. In the case of the pixel isolation region of the cross structure (DTI), optical loss may occur due to optical absorption.

[0161] The ninth isolation region 530 of the third sub-pixel 500 including the blue color filter 540 can be formed in a direction perpendicular to the direction in which the third isolation region 330 of the first sub-pixel 300 including the green color filter 340 is formed.

[0162] The blue color filter 540 can be formed above the isolation layer 590. The blue color filter 540 can filter and transmit visible light in the incident light incident on the microlens 570, and can only allow blue light in the visible light to pass through.

[0163] The photodiode 550 can be formed in the inner region of the substrate 580 and can be formed below the ninth isolation region 530, and the n-type impurity region and the p-type impurity region can be vertically stacked in the photodiode 550. The n-type impurity region and the p-type impurity region can be formed by an ion implantation process.

[0164] The color filter layer isolation region 560 can be formed above the seventh isolation region 510.

[0165] The microlens 570 can be formed above the blue color filter 540 and can be used to collect incident light entering from the outside.

[0166] In an embodiment, the substrate 580 can include a silicon (Si) material in a single crystal state.

[0167] The isolation layer 590 can be formed above the seventh isolation region 510 and the eighth isolation region 520, and can include at least one of an oxide, a nitride, or a nitrogen oxide.

[0168] Only some implementation manners and examples are described, and other implementation manners, enhancements, and variations can be made based on the content described and illustrated in this patent document.

[0169] Priority Claims and Cross-References to Related Applications

[0170] This patent document claims the priority and benefit of Korean Patent Application No. 10-2023-0156862, filed on November 14, 2023, which is hereby incorporated by reference in its entirety as part of the disclosure of this patent document.

Claims

1. An image sensing device, comprising: A pixel array, the pixel array comprising a plurality of unit pixels, Wherein, each of the unit pixels includes a plurality of sub-pixels, The first isolation region is formed in the edge region of the plurality of sub-pixels. wherein the second isolation region is formed from the first isolation region toward the central portion of each of the sub-pixels, Wherein, the second isolation area includes: a first inner isolation region protruding from a region of the first isolation region toward the central portion of the sub-pixel; and a second inner isolation region aligned with the first inner isolation region and protruding from another region of the first isolation region toward the central portion of the sub-pixel, and The third isolation region is formed in a direction orthogonal to a direction in which the first inner isolation region and the second inner isolation region are arranged.

2. The image sensing device according to claim 1, in, Each of the sub-pixels comprises: the first isolation area; the second isolation region including the first inner isolation region and the second inner isolation region; an isolation layer formed over the first inner isolation region and the second inner isolation region; forming the third isolation region below the isolation layer; a color filter formed over the isolation layer; and A microlens is formed above the color filter.

3. The image sensing device according to claim 1, in, The second inner isolation region is formed at a position spaced apart from the first inner isolation region by a certain distance.

4. The image sensing device according to claim 3, in, The third isolation region is formed from one side of the first isolation region perpendicular to the first inner isolation region or the second inner isolation region in a direction crossing between the first inner isolation region and the second inner isolation region.

5. The image sensing device according to claim 1, in, The third isolation region includes at least one of oxide, nitride, or oxynitride.

6. The image sensing device according to claim 1, in, The third isolation region includes a material different from a material of the second isolation region.

7. The image sensing device according to claim 1, in, The second isolation region includes a material having a higher refractive index than that of silicon.

8. The image sensing device according to claim 1, in, The second isolation region includes polysilicon.

9. The image sensing device according to claim 1, in, The third isolation region includes a material having a refractive index lower than that of silicon.

10. The image sensing device according to claim 1, in, A depth of the third isolation region is smaller than a depth of the second isolation region.

11. The image sensing device according to claim 1, in, The third isolation region is in contact with the second isolation region.

12. The image sensing device according to claim 1, in, The third isolation region is spaced apart from the second isolation region.

13. An image sensing device, comprising: A pixel array, the pixel array comprising a plurality of unit pixels, Among them, each unit pixel includes: a first sub-pixel, the first sub-pixel comprising a green color filter; a second sub-pixel, the second sub-pixel comprising a red filter; and a third sub-pixel, the third sub-pixel comprising a blue color filter, The first isolation region is formed in an edge region of the first sub-pixel. The fourth isolation region is formed in an edge region of the second sub-pixel. wherein a second isolation region is formed from the first isolation region toward a central portion of the first sub-pixel, wherein a fifth isolation region is formed to protrude from the fourth isolation region in a direction perpendicular to a direction in which the second isolation region is formed, Wherein, the second isolation area includes: a first inner isolation region protruding from a region of the first isolation region toward the central portion of the first sub-pixel; and a second inner isolation region aligned with the first inner isolation region and protruding from another region of the first isolation region toward the central portion of the first sub-pixel, Wherein, the fifth isolation area includes: a third inner isolation region protruding from a region of the fourth isolation region toward a central portion of the second sub-pixel; and a fourth inner isolation region aligned with the third inner isolation region and protruding from another region of the fourth isolation region toward the central portion of the second sub-pixel, wherein the third isolation region is formed in a direction orthogonal to a direction in which the first inner isolation region and the second inner isolation region are arranged, and The sixth isolation region is formed in a direction orthogonal to a direction in which the third inner isolation region and the fourth inner isolation region are arranged.

14. The image sensing device according to claim 13, in, The first sub-pixel comprises: the first isolation area; the second isolation region including the first inner isolation region and the second inner isolation region; an isolation layer formed over the first isolation region and the second isolation region; forming the third isolation region below the isolation layer; the green color filter formed over the isolation layer; and A micro lens is formed above the green filter.

15. The image sensing device according to claim 13, in, The first inner isolation region is formed at a position spaced apart from the second inner isolation region by a certain distance.

16. The image sensing device according to claim 15, in, The third isolation region is formed from one side of the first isolation region perpendicular to the first inner isolation region or the second inner isolation region in a direction crossing between the first inner isolation region and the second inner isolation region.

17. The image sensing device according to claim 13, in, The third isolation region includes at least one of oxide, nitride, or oxynitride.

18. The image sensing device according to claim 13, in, The third inner isolation region is formed at a position spaced apart from the fourth inner isolation region by a certain distance.

19. The image sensing device according to claim 18, in, The sixth isolation region is formed from one side of the fourth isolation region perpendicular to the third inner isolation region or the fourth inner isolation region in a direction crossing between the third inner isolation region and the fourth inner isolation region.

20. The image sensing device according to claim 13, in, A seventh isolation region is formed in an edge region of the third sub-pixel, wherein the eighth isolation region is formed to protrude from the seventh isolation region in a direction perpendicular to a direction in which the second isolation region is formed, Wherein, the eighth isolation area includes: a fifth inner isolation region protruding from a region of the seventh isolation region toward a central portion of the third sub-pixel; and a sixth inner isolation region aligned with the fifth inner isolation region and protruding from another region of the seventh isolation region toward the central portion of the third sub-pixel, and The ninth isolation region is formed in a direction orthogonal to a direction in which the fifth inner isolation region and the sixth inner isolation region are arranged.

Images