Image sensing device

Abstract

An image sensing device includes: a semiconductor substrate; a plurality of photoelectric conversion elements supported by the semiconductor substrate and configured to convert light into an electrical signal; and a color filter layer disposed above the semiconductor substrate and configured to include different color filters, the different color filters filtering incident light toward the photoelectric conversion elements according to a wavelength range of the incident light corresponding to the color of the incident light to allow the filtered light to be detected by the photoelectric conversion element corresponding to the color of the incident light. The color filter layer includes a plurality of first color filters, which are part of the different color filters and are configured to allow light in a wavelength range corresponding to a first color and are arranged adjacent to each other. The distance between at least one of the plurality of first color filters and a corresponding photoelectric conversion element formed below at least one of the plurality of first color filters is different from the distance between the remaining first color filters and the corresponding photoelectric conversion elements, respectively.

Description

Technical Field

[0001] The technologies and implementations disclosed in this patent document generally relate to image sensing devices. Background Art

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

[0003] Various embodiments of the disclosed technology relate to an image sensing device capable of obtaining both a long exposure pixel signal and a normal pixel signal using only one exposure.

[0004] According to an embodiment of the disclosed technology, an image sensing device may include: a semiconductor substrate; a plurality of photoelectric conversion elements supported by the semiconductor substrate and configured to convert light into electrical signals; and a color filter layer disposed above the semiconductor substrate and configured to include different color filters, where the different color filters filter incident light toward the photoelectric conversion elements according to the wavelength range of the incident light corresponding to the color of the incident light, so that the filtered light can be detected by the photoelectric conversion elements corresponding to the color of the incident light. The color filter layer may include a plurality of first color filters, which are part of the different color filters and are configured to allow light in a wavelength range corresponding to a first color and are arranged adjacent to each other. The distances between at least one of the first color filters and the corresponding photoelectric conversion elements formed below at least one of the first color filters are respectively different from the distances between the remaining first color filters and the corresponding photoelectric conversion elements.

[0005] According to another embodiment of the disclosed technology, an image sensing device may include: a first sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a first color into electrical signals; a second sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a second color into electrical signals; and a third sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a third color into electrical signals. Each of the first to third sub-pixel blocks includes at least one unit pixel including a photoelectric conversion element spaced apart from the corresponding color filter by a first distance and the remaining unit pixels including a photoelectric conversion element spaced apart from the corresponding color filter by a second distance, and wherein the first distance is different from the second distance.

[0006] It is to be understood that the foregoing general description and the following detailed description of the disclosed technology are exemplary and explanatory and are intended to provide further explanation of the claimed disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. is a schematic diagram illustrating an exemplary layout of an image sensing device exemplifying some implementations of the disclosed technology.

[0008] Figure 2 exemplifies some implementations based on the disclosed technology Figure 1 schematic diagram of an exemplary layout of the pixel array shown.

[0009] Figure 3A exemplifies some implementations based on the disclosed technology along Figure 2 cross-sectional view of an example of a pixel array taken along the line A-A' shown.

[0010] Figure 3B exemplifies some implementations based on the disclosed technology along Figure 2 cross-sectional view of an example of a pixel array taken along the line B-B' shown.

[0011] Figures 4A to 4C exemplifies some implementations based on the disclosed technology for forming Figure 3A cross-sectional view of an example of a method for forming trenches having different depths shown.

[0012] Figure 5A exemplifies some implementations based on the disclosed technology along Figure 2 cross-sectional view of another example of a pixel array taken along the line A-A' shown.

[0013] Figure 5B exemplifies some implementations based on the disclosed technology along Figure 2 cross-sectional view of another example of a pixel array taken along the line B-B' shown. DETAILED DESCRIPTION

[0014] This patent document provides implementations and examples of an image sensing device, and the disclosed features can be implemented to achieve one or more advantages in imaging applications. Some implementations of the disclosed technology propose a design of an image sensing device that can acquire both a long exposure pixel signal and a normal pixel signal using only one exposure.

[0015] Figure 1 FIG. is a block diagram of an example of an image sensing device exemplifying some implementations of the disclosed technology. Figure 2 exemplifies some implementations based on the disclosed technology Figure 1Schematic diagram of an exemplary layout of the pixel array 100 shown.

[0016] Referring to Figure 1 and Figure 2 , the image sensing device may include a pixel array 100, a correlated double sampler (CDS) 200, an analog-to-digital converter (ADC) 300, a buffer 400, a row driver 500, a timing generator 600, a control register 700, and a ramp signal generator 800.

[0017] The pixel array 100 may include a plurality of sub-pixel blocks PB_R, PB_G, and PB_B arranged continuously in a two-dimensional (2D) structure, where the sub-pixel blocks are arranged in the row direction and the column direction. Each of the sub-pixel blocks PB_R, PB_G, and PB_B may include a plurality of unit pixels (PX), which are configured to generate an electrical signal (i.e., a pixel signal) corresponding to the incident light through the photoelectric conversion of the incident light received from the outside. In this case, each of the sub-pixel blocks PB_R, PB_G, and PB_B may include a structure in which unit pixels (PX) having color filters of the same color are arranged adjacent to each other in an (N×N) array (where "N" is a natural number of 2 or greater). In Figure 1 and Figure 2 , the pixel array 100 may include sub-pixel blocks PB_R, PB_G, and PB_B, each sub-pixel block having a four-element structure in which four unit pixels of the same color are arranged in a (2×2) array. In some implementations, the sub-pixel block PB_R may include a structure in which four red pixels having a red color filter configured to selectively transmit visible light in a first wavelength band while blocking light in other wavelength bands are arranged in a (2×2) array. The sub-pixel block PB_G may include a structure in which four green pixels having a green color filter configured to selectively transmit visible light in a second wavelength band while blocking light in other wavelength bands are arranged in a (2×2) array. The sub-pixel block PB_B may include a structure in which four blue pixels having a blue color filter configured to selectively transmit visible light in a third wavelength band while blocking light in other wavelength bands are arranged in a (2×2) array. The sub-pixel blocks PB_R, PB_G, and PB_B may be arranged continuously and regularly in a Bayer pattern.

[0018] Each sub-pixel block PB_R, PB_G, or PB_B may include long exposure pixels PX LR , PX LG or PX LB . More specifically, the sub-pixel block PB_R may include long exposure pixels (PX LR ) for HDR implementation. The sub-pixel block PB_G may include long exposure pixels (PX LG)。The sub-pixel block PB_B may include long-exposure pixels (PX LB ) for HDR implementation. In the following description, among the sub-pixel blocks PB_R, PB_G, and PB_B, except for the long-exposure pixels PX LR , PX LG and PX LB , the remaining unit pixels will be defined as normal pixels PX NR , PX NG and PX NB hereinafter. More specifically, among the unit pixels in the (2×2) array except for the long-exposure pixels (PX LR ), the remaining unit pixels will be defined as normal pixels (PX NR ) hereinafter, among the unit pixels in the (2×2) array except for the long-exposure pixels (PX LG ), the remaining unit pixels will be defined as normal pixels (PX NG ) hereinafter, and among the unit pixels in the (2×2) array except for the long-exposure pixels (PX LB ), the remaining unit pixels will be defined as normal pixels (PX NB ) hereinafter. The long-exposure pixels PX LR , PX LG and PX LB may refer to pixels formed as follows: compared with the normal pixels PX NR , PX NG and PX NB , the photoelectric conversion elements of the long-exposure pixels PX LR , PX LG and PX LB can be quickly saturated during the same exposure time. Therefore, although the pixel array 100 is exposed only once, the pixel array 100 can generate a pixel signal corresponding to the saturated photoelectric conversion element (i.e., the long-exposure pixel signal) and a pixel signal corresponding to the non-saturated photoelectric conversion element (i.e., the normal pixel signal).

[0019] For this reason, the photoelectric conversion element of the long-exposure pixel (PX LR ) can be different in size (or volume) from each of the photoelectric conversion elements of the normal pixel (PX NR ), the photoelectric conversion element of the long-exposure pixel (PX LG ) can be different in size (or volume) from each of the photoelectric conversion elements of the normal pixel (PX NG ), and the photoelectric conversion element of the long-exposure pixel (PX LB ) can be different in size (or volume) from each of the photoelectric conversion elements of the normal pixel (PX NB ). In addition, according to the color of the corresponding pixel, the long-exposure pixels PX LR , PX LGand PX LB The photoelectric conversion elements can be formed to have different sizes. The long exposure pixels PX LR , PX LG and PX LB will be described in detail later.

[0020] As described above, each unit pixel PX can output a pixel signal to the correlated double sampler (CDS) 200. The CMOS image sensor can use correlated double sampling (CDS) to remove an undesired pixel offset value by sampling the pixel signal twice to remove the difference between the two samplings. In one example, correlated double sampling (CDS) can remove an undesired pixel offset value by comparing the pixel output voltages obtained before and after the optical signal is incident on the pixel, so that only the pixel output voltage based on the incident light can be measured. In some embodiments of the disclosed technology, the correlated double sampler (CDS) 200 can sequentially sample and hold the voltage levels of the reference signal and the image signal provided to each of the multiple column lines from the pixel array 100. For example, the correlated double sampler (CDS) 200 can perform sampling of the voltage levels of the received pixel signal and the reference voltage level in response to the clock signal received from the timing generator 600, and can send an analog signal corresponding to the difference between the voltage levels of the received pixel signal and the reference voltage level to the analog-to-digital converter (ADC) 300.

[0021] The analog-to-digital converter (ADC) 300 can be used to convert the analog CDS signal into a digital signal. In some implementations, the ADC 300 can be implemented as a ramp comparison type ADC. The ramp comparison type ADC can include a comparator circuit for comparing the analog pixel signal with a reference signal such as a ramp up or down ramp signal and a timer for counting until the voltage of the ramp signal matches the analog pixel signal. In some embodiments of the disclosed technology, the ADC 300 can convert the correlated double sampling signal generated by the CDS 200 for each column into a digital signal and output the digital signal. The ADC 300 can perform a counting operation and a calculation operation based on the correlated double sampling signal for each column and the ramp signal received from the ramp signal generator 800. In this way, the ADC 300 can eliminate or reduce noises such as reset noise that appear in the imaging pixels when generating digital image data.

[0022] The ADC 300 may include a plurality of column counters. Each column of the pixel array 100 is coupled to a column counter, and image data may be generated by converting the correlated double-sampled signals received from each column into digital signals by using the column counters. In another embodiment of the disclosed technology, the ADC 300 may include a global counter to convert the correlated double-sampled signals corresponding to columns into digital signals by using global codes provided from the global counter.

[0023] The buffer 400 may temporarily hold or latch each of the digital signals received from the analog-to-digital converter (ADC) 300, may sense or detect and amplify each of the digital signals, and may output each of the amplified digital signals. Accordingly, the buffer 400 may include a memory (not shown) and a sense amplifier (not shown). The memory may store count values, and the count values may be associated with the output signals of the plurality of unit pixels PX. The sense amplifier may sense and amplify each of the count values received from the memory.

[0024] The row driver 500 may be used to drive the pixel array 100 in response to the output signal of the timing generator 600. In some implementations, the row driver 500 may select one or more imaging pixels arranged in one or more rows of the pixel array 100. The row driver 500 may generate row selection signals to select one or more rows among the plurality of rows. The row decoder 500 may sequentially enable a pixel reset signal for resetting the imaging pixels corresponding to at least one selected row and a transmission signal for the pixels corresponding to at least one selected row.

[0025] The timing generator 600 may generate timing signals to control the row driver 500, the correlated double-sampler (CDS) 200, the analog-to-digital converter (ADC) 300, and the ramp signal generator 800.

[0026] The control register 700 may generate control signals to control the ramp signal generator 800, the timing generator 600, and the buffer 400.

[0027] The ramp signal generator 800 may generate a ramp signal in response to the control signal of the control register 700 and the timing signal received from the timing generator 600, and may output the ramp signal to the analog-to-digital converter (ADC) 300.

[0028] Refer to Figure 2 , the pixel array 100 includes a plurality of sub-pixel blocks PB_R, PB_G, and PB_B, and each sub-pixel block includes a plurality of unit pixels (PX). In one implementation, each sub-pixel block PB_R may include one long-exposure pixel (PX LR ), and each sub-pixel block PB_G may include one long-exposure pixel (PXLG ), and each sub-pixel block PB_B may include one long-exposure pixel (PX LB ). In another implementation, each of the sub-pixel blocks PB_R, PB_G, and PB_B may include multiple long-exposure pixels. In some implementations, the exposure degree of the light applied to the image sensing device can be changed by increasing or decreasing the time of each exposure. For example, in HDR imaging, exposure changes can be made by changing the exposure time. In some embodiments of the disclosed technology, each sub-pixel block in the pixel array may include at least one long-exposure pixel, and this long-exposure pixel can be achieved by varying the thickness of the layer disposed under the color filter layer. Although Figure 2 each of the sub-pixel blocks PB_R, PB_G, and PB_B is illustrated as including one long-exposure pixel (i.e., long-exposure pixels PX LR , PX LG and PX LB ), the scope of the disclosed technology is not limited thereto. In another exemplary implementation, one sub-pixel block (or two sub-pixel blocks) selected among the sub-pixel blocks PB_R, PB_G, and PB_B may include such long-exposure pixels PX LR , PX LG or PX LB . Although Figure 2 the long-exposure pixels PX LR , PX LG or PX LB are illustrated as being formed at the same positions in the sub-pixel blocks PB_R, PB_G, or PB_B, the positions of the long-exposure pixels PX LR , PX LG and PX LB in the sub-pixel blocks PB_R, PB_G, and PB_B can vary.

[0029] Figure 3A is an example cross-sectional view of the pixel array 100 taken along the line A-A' as shown in Figure 2 illustrating some implementations based on the disclosed technology. Figure 3B is an example cross-sectional view of the pixel array 100 taken along the line B-B' as shown in Figure 2 illustrating some implementations based on the disclosed technology.

[0030] In some embodiments of the disclosed technology, each sub-pixel block in the pixel array may include multiple pixels, such that the long-exposure pixels include a material layer and a photoelectric conversion element different from other pixels (such as normal pixels or long-exposure pixels). In one example, the long-exposure pixels may include an anti-reflection layer and / or a silicon layer, which are formed under the color filter and have a different thickness from other anti-reflection layers and / or silicon layers formed under other pixels (such as normal pixels or long-exposure pixels). In one example, the long-exposure pixels may include a smaller photoelectric conversion element than those of other pixels (such as normal pixels or long-exposure pixels). In one example, the long-exposure pixels may be formed such that the distance between the long-exposure photoelectric conversion element and its corresponding color filter is longer than the distance between a normal photoelectric conversion element and its corresponding color filter. Referring to Figure 3A and Figure 3B , the semiconductor substrate 110 may include a first surface and a second surface facing away from each other. The semiconductor substrate 110 may include a single-crystalline material layer. For example, the semiconductor substrate 110 may include a material layer containing silicon. In some implementations, the semiconductor substrate 110 may include a single-crystalline silicon layer. The semiconductor substrate 110 may include multiple photoelectric conversion elements. As Figure 3A and Figure 3B shown, each unit pixel PX is one of the photoelectric conversion elements 112a, 112b, 112c, and 112d. The photoelectric conversion elements 112a, 112b, 112c, and 112d may convert incident light (e.g., visible light) filtered by the color filter layer 130 into an electrical signal.

[0031] According to the type and color of the corresponding pixel, the semiconductor substrate 110 in the corresponding pixel is formed to have different thicknesses. For example, in each sub-pixel block PB_R, PB_G, or PB_B, the region where the long-exposure pixel PX LR , PX LG or PX LB is formed and the region where the normal pixel PX NR , PX NG or PX NB is formed may have different thicknesses from each other. More specifically, in the sub-pixel block PB_R, the first region where the long-exposure pixel (PX LR ) is formed and the second region where the normal pixel (PX NR ) is formed may have different thicknesses from each other. In the sub-pixel block PB_G, the third region where the long-exposure pixel (PX LG ) is formed and the fourth region where the normal pixel (PX NG ) is formed may have different thicknesses from each other. In the sub-pixel block PB_B, the region where the long-exposure pixel (PX LB)'s fifth region and the sixth region formed therein with normal pixels (PX NB ) can have different thicknesses from each other. Here, the first region, the third region, and the fifth region where the long-exposure pixels PX LR , PX LG , PX LB are formed have a smaller depth than the regions where the normal pixels PX NR , PX NG or PX NB are formed. In one example, the long-exposure pixels PX LR , PX LG , PX LB can be formed such that the distance between their long-exposure photoelectric conversion elements and the color filters is longer than the distance between the normal photoelectric conversion elements and their corresponding color filters.

[0032] As described above, since the portion of the semiconductor substrate 110 disposed between the color filter and the photoelectric conversion element corresponding to the long-exposure pixels PX LR , PX LG or PX LB has a greater depth than the normal pixels PX NR , PX NG or PX NB , the sizes of the photoelectric conversion elements 112b, 112c, or 112d of the long-exposure pixels PX LR , PX LG or PX LB can be smaller than the sizes of each of the photoelectric conversion elements 112a of the normal pixels PX NR , PX NG or PX NB . Therefore, during the same exposure time, the photoelectric conversion elements 112b, 112c, and 112d of the long-exposure pixels PX LR , PX LG and PX LB can saturate faster than the photoelectric conversion elements 112a of the normal pixels PX NR , PX NG and PX NB .

[0033] The long-exposure pixels PX LR , PX LG and PX LB receive visible light in different wavelength bands according to the colors of the corresponding pixels. Therefore, the long-exposure pixels PX LR , PX LG , PX LBFormed such that the distance between its long-exposure photoelectric conversion element and the color filter can vary according to the wavelength band corresponding to the color of the pixel. If the portions of the semiconductor substrate 110 corresponding to the long-exposure pixels PX LR 、PX LG 、PX LB have the same thickness regardless of their corresponding wavelength bands (colors), then the amount of light absorbed by the photoelectric conversion elements 112b, 112c, and 112d can vary according to the color of the corresponding pixel. Therefore, the substrates of the long-exposure pixels PX LR 、PX LG or PX LB are formed thinner than the substrates of the normal pixels PX NR 、PX NG or PX NB , and the thickness of the substrates of the long-exposure pixels PX LR 、PX LG or PX LB can be formed differently according to the colors of the long-exposure pixels PX LR 、PX LG and PX LB .

[0034] For example, the portion of the substrate corresponding to the long-exposure pixel PX LR including a red color filter and configured to convert red visible light having a first wavelength band can be formed thicker than the portion of the substrate corresponding to the long-exposure pixel PX LG including a green color filter and configured to convert green visible light having a second wavelength band shorter than the first wavelength band. In addition, the portion of the substrate corresponding to the long-exposure pixel PX LG including a green color filter can be formed thicker than the portion of the substrate corresponding to the long-exposure pixel PX LB including a blue color filter and configured to convert blue visible light having a third wavelength band shorter than the second wavelength band. Therefore, the distance between the photoelectric conversion element 112b of the long-exposure pixel PX LR and the corresponding red color filter can be closer than the distance between the photoelectric conversion element 112c of the long-exposure pixel PX LG and the corresponding green color filter. In some implementations, the photoelectric conversion element 112b of the long-exposure pixel PX LR including a red color filter can have a larger size (volume) than the photoelectric conversion element 112c of the long-exposure pixel PX LG including a green color filter. Additionally, the distance between the photoelectric conversion element 112c of the long-exposure pixel PX LG and the corresponding green color filter can be closer than the distance between the photoelectric conversion element 112c of the long-exposure pixel PX LBThe distance between the photoelectric conversion element 112d and the corresponding blue color filter is closer. In some implementations, the long exposure pixel PX including the green color filter LG The photoelectric conversion element 112c may have a larger size (volume) than the long exposure pixel PX including the blue color filter LB The photoelectric conversion element 112d.

[0035] To form the portions of the semiconductor substrate 110 having different thicknesses as described above, trenches 114a, 114b, and 114c with different depths may be formed in the substrate regions of the long exposure pixels PX LR 、PX LG and PX LB respectively. By adjusting the depths of the trenches 114a, 114b, and 114c, the semiconductor substrates 110 of the long exposure pixels PX LR 、the semiconductor substrates 110 of the long exposure pixels PX LG and the semiconductor substrates 110 of the long exposure pixels PX LB may have different thicknesses from each other.

[0036] In some implementations, an antireflection layer 120 may be formed in the trenches 114a, 114b, and 114c above the first surface of the semiconductor substrate 110. In one example, the antireflection layer 120 may include a single-layer structure formed of at least one of the group including an oxide film, a nitride film, and an oxynitride film. In another example, the antireflection layer 120 may include a multilayer structure formed by laminating at least two of an oxide film, a nitride film, and an oxynitride film.

[0037] The color filter layer 130 may be formed over the antireflection layer 120. The color filter layer 130 may include a plurality of color filters (i.e., RGB color filters), each color filter being formed to selectively filter only visible light having a wavelength corresponding to a specific color such that the filtered light is fed to the corresponding photoelectric conversion elements 112a, 112b, 112c, and 112d. More specifically, the color filter layer 130 including a plurality of red filters (Rs), a plurality of green filters (Gs), and a plurality of blue filters (Bs) may filter incident light, and visible light of a specific wavelength (e.g., red light, green light, or blue light) is fed to the corresponding photoelectric conversion elements 112a, 112b, 112c, and 112d while blocking light of other wavelengths. Each red filter (R) allows red visible light having a first wavelength band to pass through. Each green filter (G) allows green visible light having a second wavelength band to pass through. Each blue filter (B) allows blue visible light having a third wavelength band to pass through. Each unit pixel (PX) includes one of the filters R, G, and B. The red filter (R) may include a polymeric organic material containing a red pigment, the green filter (G) may include a polymeric organic material containing a green pigment, and the blue filter (B) may include a polymeric organic material containing a blue pigment. For example, each of the filters R, G, and B may include a resist material.

[0038] The grid structure 140 may define regions in which the filters R, G, and B are formed and may be formed between the filters R, G, and B, thereby preventing crosstalk between adjacent filters R, G, and B. In some implementations, the area of the region defined by the grid structure 140 (i.e., the aperture area) is the same for long exposure pixels (PX LR 、PX LG 、PX LB ) and normal pixels (PX NR 、PX NG 、PX NB ).

[0039] The lens layer 150 may include an outer coating 152 and a plurality of microlenses 154. In some implementations, the outer coating 152 and the microlenses 154 may be formed of the same material. The outer coating 152 may be formed over the color filter layer 130. The outer coating 152 may be used to planarize an uneven surface after the color filter layer 130 is formed. The microlenses 154 may be formed over the outer coating 152. Each of the microlenses 154 may be formed in a hemispherical shape and may be formed over each corresponding unit pixel (PX). The microlenses 154 may converge incident light onto the corresponding filters R, G, and B.

[0040] Figures 4A to 4C illustrates some implementations based on the disclosed technology for formingFigure 3A Cross-sectional view of an example of a method with trenches of different depths.

[0041] Referring to Figure 4A , a mask pattern 162 is formed to define an area where long-exposure pixels PX are to be formed above the first surface of the semiconductor substrate 110. LB That is, the mask pattern 162 can expose the area where the long-exposure pixels PX LB are to be formed. In one example, the mask pattern 162 can include a photoresist pattern.

[0042] Subsequently, the semiconductor substrate 110 can be etched using the mask pattern 162 as an etching mask to form trenches 114c'. In this case, the depth of the trenches 114c' can correspond to Figure 3A the difference between the depth of the trenches 114c shown and the depth of the trenches 114b.

[0043] Referring to Figure 4B , after removing the mask pattern 162, a mask pattern 164 is formed to define an area where long-exposure pixels PX LB and PX LG are to be formed above the first surface of the semiconductor substrate 110. That is, the mask pattern 164 can be formed to expose the trenches 114c' and the long-exposure pixels PX Figure 4A formed in the process of LG .

[0044] Thereafter, the semiconductor substrate 110 can be etched using the mask pattern 164 as an etching mask to form trenches 114c'' and 114b'. In this case, the depth of the trenches 114c'' can correspond to Figure 3A the difference between the depth of the trenches 114c shown and the depth of the trenches 114a, and the depth of the trenches 114b' can correspond to the difference between the depth of the trenches 114b and the depth of the trenches 114a.

[0045] In other words, since the trenches 114b' are formed after the trenches 114c', during the process of forming the trenches 114b', the trenches 114c' can be additionally etched to an extent corresponding to the depth of the trenches 114b'. In this way, the trenches 114c'' are formed.

[0046] Referring to Figure 4C , after removing the mask pattern 164, a mask pattern 166 is formed to define an area where long-exposure pixels PX LR , PX LG and PX LB are to be formed above the first surface of the semiconductor substrate 110. That is, the mask pattern 166 can be formed to expose the areas formed by Figure 4BThe trenches 114c” and 114b’ formed by the process shown and the regions corresponding to the remaining long-exposure pixels (PX LR ).

[0047] Subsequently, the semiconductor substrate 110 can be etched to the depth of the trench 114a using the mask pattern 166 as an etch mask to form trenches 114c, 114b, and 114a.

[0048] Figure 5A is a cross-sectional view of another example of the pixel array 100 taken along the line A-A’ shown in Figure 2 illustrating some implementations based on the disclosed technology. Figure 5B is a cross-sectional view of another example of the pixel array 100 taken along the line B-B’ shown in Figure 2 illustrating some implementations based on the disclosed technology.

[0049] Referring to Figure 5A and Figure 5B , a barrier film 122 can be additionally formed in each boundary region between the long-exposure pixels (PX LR , PX LG , PX LB ) and the normal pixels (PX NR , PX NG , PX NB ) in the antireflection layer 120. For example, the barrier film 122 can be formed in the antireflection layer 120 between the color filter layer 140 and the first surface of the semiconductor substrate 110 such that the barrier film 122 can vertically overlap with the grid structure 140 between the long-exposure pixels (PX LR , PX LG , PX LB ) and the normal pixels (PX NR , PX NG , PX NB ). In this case, the top surface of the barrier film 122 can contact the bottom surface of the gate structure 140, and the bottom surface of the barrier film 122 can contact the first surface of the semiconductor substrate 110.

[0050] The barrier film 122 can prevent crosstalk caused by the antireflection layer 120 provided between the long-exposure pixels (PX LR , PX LG , PX LB ) and the normal pixels (PX NR , PX NG , PX NB ). Here, the barrier film 122 can include a metal material.

[0051] As is apparent from the above description, an image sensing device according to some implementations of the disclosed technology may implement long exposure pixels having a different structure from other pixels to obtain both a long exposure pixel signal and a normal pixel signal without changing the exposure time.

[0052] Although multiple exemplary embodiments have been described, it should be understood that various modifications and other embodiments of the disclosed embodiments may be designed based on what is described and / or illustrated in this patent document.

[0053] Cross - reference to related applications

[0054] This patent document claims the priority and benefit of Korean Patent Application No. 10 - 2020 - 0114554, filed on September 8, 2020, the entire content of which is incorporated herein by reference as part of the disclosure of this patent document.

Claims

1. An image sensing device, the image sensing device comprising: A semiconductor substrate; A plurality of photoelectric conversion elements supported by the semiconductor substrate and configured to convert light into an electrical signal; And A color filter layer disposed above the semiconductor substrate and configured to include different color filters, the different color filters filtering the incident light toward the photoelectric conversion elements according to the wavelength range of the incident light corresponding to the color of the incident light to allow the filtered light to be detected by the photoelectric conversion elements corresponding to the color of the incident light, Wherein, the color filter layer includes a plurality of first color filters, the plurality of first color filters being part of the different color filters and configured to allow light to be in a wavelength range corresponding to a first color and being arranged adjacent to each other, and Wherein, the distance between at least one of the plurality of first color filters and the corresponding photoelectric conversion element formed below the at least one of the plurality of first color filters is different from the distance between the remaining first color filters and the corresponding photoelectric conversion elements, respectively.

2. The image sensing device according to claim 1, wherein, The plurality of first color filters are arranged such that four of the plurality of first color filters are arranged in a 2×2 matrix.

3. The image sensing device according to claim 1, wherein The color filter layer further includes: A plurality of second color filters configured to allow light to be in a wavelength range corresponding to a second color and arranged adjacent to each other; and A plurality of third color filters configured to allow light to be in a wavelength range of a third color and arranged adjacent to each other.

4. The image sensing device according to claim 3, wherein, The distance between at least one of the plurality of second color filters and the corresponding photoelectric conversion element formed below the at least one of the plurality of second color filters is different from the distance between the remaining second color filters and the corresponding photoelectric conversion elements, respectively.

5. The image sensing device according to claim 3, wherein, The distance between at least one of the plurality of third color filters and the corresponding photoelectric conversion element formed below the at least one of the plurality of third color filters is different from the distance between the remaining third color filters and the corresponding photoelectric conversion elements, respectively.

6. The image sensing device according to claim 3, wherein, The semiconductor substrate includes: A first trench, at least one of the plurality of first color filters being formed in the first trench; A second trench, at least one of the plurality of second color filters being formed in the second trench; and A third trench, at least one of the plurality of third color filters being formed in the third trench, Wherein, the first trench to the third trench have different depths from each other.

7. The image sensing device according to claim 1, the image sensing device further comprising: An antireflection layer disposed between the photoelectric conversion elements and the color filter layer.

8. The image sensing device according to claim 7, wherein, The portion of the antireflection layer corresponding to at least one of the plurality of first color filters has a thickness different from that of the portion of the antireflection layer corresponding to the remaining first color filters.

9. The image sensing device according to claim 1, further comprising: An antireflection layer disposed between a first surface of the semiconductor substrate and the color filter layer.

10. The image sensing device according to claim 9, further comprising: A blocking film disposed in the antireflection layer and configured to vertically overlap a grid structure disposed between at least one of the plurality of first color filters and the remaining first color filters.

11. An image sensing device, comprising: A first sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a first color into an electrical signal; A second sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a second color into an electrical signal; And A third sub-pixel block including a plurality of unit pixels arranged adjacent to each other and configured to convert light in a wavelength range corresponding to a third color into an electrical signal, wherein each of the first sub-pixel block to the third sub-pixel block includes at least one unit pixel including a photoelectric conversion element spaced apart from a corresponding color filter by a first distance and the remaining unit pixels including a photoelectric conversion element spaced apart from the corresponding color filter by a second distance, and wherein the first distance is different from the second distance.

12. The image sensing device according to claim 11, wherein Each of the first sub-pixel block to the third sub-pixel block includes four pixels of the same color arranged adjacent to each other in a 2×2 matrix array.

13. The image sensing device according to claim 11, wherein In each of the first sub-pixel block to the third sub-pixel block, the photoelectric conversion element of the at least one unit pixel has a thickness different from that of the photoelectric conversion element of the remaining unit pixels.

14. The image sensing device according to claim 11, wherein, The first sub-pixel block includes: A plurality of first normal pixels, each of the plurality of first normal pixels including a first photoelectric conversion element having a first height; and At least one first long exposure pixel including a second photoelectric conversion element having a second height lower than the first height.

15. The image sensing device according to claim 14, wherein, The second sub-pixel block includes: A plurality of second normal pixels, each of the plurality of second normal pixels including a third photoelectric conversion element having the first height; and At least one second long exposure pixel including a fourth photoelectric conversion element having a third height lower than the second height.

16. The image sensing device according to claim 15, wherein, The third sub-pixel block includes: A plurality of third normal pixels, each of the plurality of third normal pixels including a fifth photoelectric conversion element having the first height; and At least one third-longest exposure pixel, wherein the at least one third-longest exposure pixel includes a sixth photoelectric conversion element having a fourth height lower than the third height.

17. The image sensing device according to claim 11, wherein, The first sub-pixel block to the third sub-pixel block are arranged in a Bayer pattern.

18. The image sensing device according to claim 11, further comprising: An antireflection layer, the antireflection layer being disposed between the photoelectric conversion element and the color filter layer.

19. The image sensing device according to claim 11, further comprising: An antireflection layer, the antireflection layer being disposed above a first surface of the semiconductor substrate.

20. The image sensing device according to claim 19, further comprising: A barrier film, the barrier film being disposed in the antireflection layer in a boundary region between the at least one unit pixel and the remaining unit pixels other than the at least one unit pixel.

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