Pixel structure and image sensor

Abstract

The present application belongs to the field of semiconductor device technology, and relates to a pixel structure and an image sensor, wherein the pixel structure includes a plurality of pixel units and a first metal wire. The plurality of pixel units are arranged in a honeycomb shape, and the pixel units of odd rows are in different column positions from the pixel units of adjacent even rows. Each pixel unit is hexagonal, and each pixel unit includes a photosensitive area and a first side wiring area and a second side wiring area that are symmetrical in the column direction. The first metal wire connects at least one pixel unit of an odd row and at least one pixel unit of an even row in the same column, and in the same column, the first metal wire is routed in the first side wiring area of ​​the pixel units of odd rows, and is routed in the second side wiring area of ​​the pixel units of even rows. Therefore, the present application can improve or avoid the problem of metal light blocking in the photosensitive area of ​​the pixel unit, thereby achieving the purpose of improving the detection effect of the image sensor.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a pixel structure and an image sensor. Background Art

[0002] With the development of image sensor technology, the application fields of image sensors are becoming more and more extensive. For example, image sensors can be applied to medical radiation imaging, industrial flaw detection, security inspection and other fields.

[0003] At present, the pixel structure of image sensors for fluorescent sequencing applications can use hexagonal pixel units arranged in a honeycomb pattern. However, the hexagonal pixel units arranged in a honeycomb pattern are different from the pixel unit array arranged in a traditional checkerboard array. Because the pixel units in adjacent rows of the hexagonal pixel units arranged in a honeycomb pattern are not at the same column position coordinates while maintaining the same row position coordinates, if the hexagonal pixel units arranged in a honeycomb pattern use vertical metal wires like the pixel unit array arranged in a traditional checkerboard array, it will cause the problem of metal blocking light in the photosensitive area of ​​the pixel unit, which will directly affect the detection effect of the image sensor.

[0004] In view of the above problems, those skilled in the art have been seeking solutions.

[0005] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the invention

[0006] The technical problem to be solved by the present application is that, in view of the defects of the above-mentioned prior art, a pixel structure and an image sensor are provided to optimize the routing of the hexagonal pixel unit array with a honeycomb arrangement, improve or avoid the problem of metal light blocking in the photosensitive area of ​​the pixel unit, thereby achieving the purpose of improving the detection effect of the image sensor.

[0007] This application is implemented as follows:

[0008] The present application provides a pixel structure, including a plurality of pixel units and a first metal line. The plurality of pixel units are arranged in a honeycomb shape, and the pixel units in odd rows are in different column positions from the pixel units in adjacent even rows. Each pixel unit is hexagonal, and each pixel unit includes a photosensitive area and a first side wiring area and a second side wiring area that are symmetrical in the column direction. The first metal line connects at least one pixel unit in an odd row and at least one pixel unit in an even row in the same column, and in the same column, the first metal line is routed in the first side wiring area of ​​the pixel units in the odd rows, and is routed in the second side wiring area of ​​the pixel units in the even rows.

[0009] Optionally, the first metal line includes at least one straight line segment, at least one first oblique line segment and / or at least one second oblique line segment. Two adjacent straight line segments of the first metal line are connected by the first oblique line segment or the second oblique line segment, and the first oblique line segment of the first metal line and the second oblique line segment of the first metal line have different inclination directions. The first side wiring area of ​​the pixel unit of the odd-numbered rows and the second side wiring area of ​​the pixel unit of the even-numbered rows both include the straight line segment, the first oblique line segment and / or the second oblique line segment of the first metal line.

[0010] Optionally, each pixel unit includes a hexagonal effective pixel boundary, and the hexagonal effective pixel boundary includes a column-oriented vertical edge, a first inclined edge, and a second inclined edge. The straight line segment of the first metal line is parallel to the adjacent column-oriented vertical edge, the first oblique line segment of the first metal line is parallel to the adjacent first inclined edge, and the second oblique line segment of the first metal line is parallel to the adjacent second inclined edge. The straight line segment of the first metal line forms a first corner with the first oblique line segment of the adjacent first metal line, and forms a second corner with the second oblique line segment of the adjacent first metal line, and the first corner and the second corner are both 120°.

[0011] Optionally, a second metal line is further included. The second metal line connects at least one pixel unit in an odd row and at least one pixel unit in an even row in the same column, and in the same column, the second metal line is routed in the second side routing area of ​​the pixel unit in the odd row and is routed in the first side routing area of ​​the pixel unit in the even row.

[0012] Optionally, the second metal line is symmetrical to the adjacent first metal line.

[0013] Optionally, the first metal line is a power signal transmission line, and the second metal line is a data readout line.

[0014] Optionally, the photosensitive area of ​​each pixel unit is a photodiode located at the center thereof, wherein the photodiode includes one of a hexagonal photodiode, an octagonal photodiode, and a circular photodiode.

[0015] Optionally, the side length of the hexagonal effective pixel boundary of each pixel unit is 3 μm. The side length of the hexagonal photodiode is 1.8 μm. Or, the octagonal photodiode includes four long sides and four short sides, wherein the length of the long side is 1.6 μm and the length of the short side is 1.13 μm.

[0016] Optionally, the upper surface of each pixel unit corresponds to a circular microlens unit, and the radius of the microlens unit is 2.5 μm.

[0017] Optionally, each pixel unit further includes a transmission transistor and a restart transistor connected in sequence. The transmission transistor is connected to the bottom of the column of the photosensitive area, and a floating node is included between the transmission transistor and the restart transistor.

[0018] Optionally, the gate of the transfer transistor is shaped like an inverted trapezoid at the lower end of the column, and the restart transistor is connected to the short bottom side of the inverted trapezoid.

[0019] Optionally, the floating node is multiplexed with the source end of the restart transistor, and a linear arrangement structure is adopted to reduce the area of ​​the active region at the floating node.

[0020] Optionally, a dual conversion gain control transistor is further connected between the transfer transistor and the restart transistor. The dual conversion gain control transistor is multiplexed with the floating node and the source end of the restart transistor, and a linear arrangement structure is adopted to reduce the area of ​​the active region at the floating node.

[0021] Optionally, at least two columns of pixel units are included, and a source follower is further included. The source follower is arranged at the intersection of three hexagonal pixel units.

[0022] Optionally, a driving signal line for row direction routing is also included, and the routing process of the driving signal line bypasses the source follower in the horizontal direction. The driving signal line includes at least one of a driving signal line of a transmission transistor, a driving signal line of a dual conversion gain control transistor, and a driving signal line of a restart transistor.

[0023] Optionally, a row selection transistor is provided next to the source follower. The row selection transistor and the source follower share a source. The drive signal line also includes a drive signal line of the row selection transistor.

[0024] Optionally, the first metal line is connected to the source of the source follower and covers the source of the source follower, and a metal light blocking layer is provided on the first metal line, and the metal light blocking layer is located above the source of the source follower. And / or, the second metal line is connected to the drain of the source follower and covers the drain of the source follower, and a metal light blocking layer is provided on the second metal line, and the metal light blocking layer is located above the drain of the source follower.

[0025] The present application also provides an image sensor, comprising the pixel structure described above.

[0026] The present application provides a pixel structure and an image sensor, wherein the pixel structure includes a plurality of pixel units and a first metal line. The plurality of pixel units are arranged in a honeycomb shape, and the pixel units in odd rows are in different column positions from the pixel units in adjacent even rows. Each pixel unit is a hexagon, and each pixel unit includes a photosensitive area and a first side routing area and a second side routing area that are symmetrical in the column direction. The first metal line connects at least one pixel unit in an odd row and at least one pixel unit in an even row in the same column, and in the same column, the first metal line is routed in the first side routing area of ​​the pixel unit in the odd row and in the second side routing area of ​​the pixel unit in the even row. Therefore, the pixel structure provided by the present application, for the pixel units arranged in a honeycomb shape, in the same column, allows the metal line to be bent and routed between the pixel units in the odd rows and the pixel units in the adjacent even rows to bypass the photosensitive area of ​​each pixel unit, so that the present application can improve or avoid the problem of metal light blocking in the photosensitive area of ​​the pixel unit, thereby achieving the purpose of improving the detection effect of the image sensor.

[0027] In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites preferred embodiments and describes them in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a first plan schematic diagram of the pixel structure provided in the first embodiment of the present application.

[0029] Figure 2 This is a first schematic diagram of a pixel unit of a pixel structure provided in the first embodiment of the present application.

[0030] Figure 3 This is a second schematic diagram of a pixel unit of the pixel structure provided in the first embodiment of the present application.

[0031] Figure 4 It is a second plan schematic diagram of the pixel structure provided in the first embodiment of the present application.

[0032] Figure 5 It is a third plan schematic diagram of the pixel structure provided in the first embodiment of the present application.

[0033] Figure 6 It is a fourth plan schematic diagram of the pixel structure provided in the first embodiment of the present application.

[0034] Figure 7 It is a first layout schematic diagram of the transmission circuit provided in the first embodiment of the present application.

[0035] Figure 8 It is a first layout schematic diagram of a source follower provided in the first embodiment of the present application.

[0036] Fig. 9It is a second layout schematic diagram of the transmission circuit provided in the first embodiment of the present application.

[0037] Fig.10 It is a second schematic layout diagram of the source follower provided in the first embodiment of the present application.

[0038] Fig.11 It is a third schematic layout diagram of the source follower provided in the first embodiment of the present application.

[0039] Fig.12 It is a plan view schematic diagram of a pixel structure provided in the second embodiment of the present application.

[0040] Fig.13 It is a second layout diagram of the source follower provided in the second embodiment of the present application.

[0041] Fig.14 It is a second layout diagram of the source follower provided in the second embodiment of the present application.

[0042] Fig.15 It is a third schematic layout diagram of the source follower provided in the second embodiment of the present application. DETAILED DESCRIPTION

[0043] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] First embodiment:

[0045] In order to clearly describe the pixel structure provided by the first embodiment of the present application, see Figures 1 to 11 .

[0046] The pixel structure provided in the first embodiment of the present application includes a plurality of pixel units P1 and a first metal line L1.

[0047] Wherein, a plurality of pixel units P1 are arranged in a honeycomb shape (for example, Figure 1 , two rows of multiple pixel units P1 arranged in a honeycomb pattern are shown, and the pixel units P1 in the odd rows are at different column positions from the pixel units P1 in the adjacent even rows. Each pixel unit P1 is hexagonal, and each pixel unit P1 includes a photosensitive area PD and a first side wiring area K1 and a second side wiring area K2 that are symmetrical in the column direction.

[0048] In an optional implementation, each pixel unit P1 is preferably a regular hexagon.

[0049] In an optional implementation, the photosensitive region PD in the pixel unit P1 may be a photodiode or a grating, etc. Preferably, the photosensitive region PD in the pixel unit P1 is a photodiode, wherein the photodiode may be obtained by forming an n-type doping region on a substrate.

[0050] In an optional embodiment, the photosensitive area PD of each pixel unit P1 is located at the center thereof, wherein the photosensitive area PD may include one or more of a hexagonal photosensitive area PD1 (e.g., a regular hexagonal photodiode), an octagonal photosensitive area PD2 (e.g., an octagonal photodiode), a circular photosensitive area (e.g., a circular photodiode), and the like.

[0051] In an optional embodiment, each pixel unit P1 includes a hexagonal effective pixel boundary B1. The photosensitive area PD of the pixel unit P1 is located at the center of the area surrounded by the hexagonal effective pixel boundary B1, and there is a certain distance between the photosensitive area PD of the pixel unit P1 and the hexagonal effective pixel boundary B1, so as to form a blank area (or wiring area, active area) between the photosensitive area PD of the pixel unit P1 and the hexagonal effective pixel boundary B1. Preferably, for the convenience of description, the blank area formed between the photosensitive area PD of the pixel unit P1 and the hexagonal effective pixel boundary B1 is divided into a first side wiring area K1 and a second side wiring area K2 by a virtual column-wise symmetry line.

[0052] See also Figure 2 In an optional embodiment, considering the use of a hexagonal effective pixel shape (i.e., having a hexagonal effective pixel boundary B1), in order to match the hexagonal effective pixel boundary B1 and achieve the maximum effective photosensitivity area, we have also optimized the shape of the photodiode, and the photosensitivity area PD can be set to a hexagonal photodiode PD1. Therefore, the hexagonal photodiode PD1 located at the center of the area surrounded by the hexagonal effective pixel boundary B1 can well receive the effective fluorescent signal transmitted by the light-guiding fiber in the optical fiber panel and then converged by the microlens on the surface of the pixel unit P1 (preferably, the upper surface of each pixel unit P1 corresponds to a microlens unit), and the distance between each side of the hexagonal photodiode PD1 and each side of the hexagonal effective pixel boundary B1 is fixed and consistent, which can achieve a better isolation effect between the pixel units P1, that is, it can better suppress crosstalk. In order to facilitate understanding of the size matching relationship between the microlens unit corresponding to the upper surface of the pixel unit P1, the hexagonal photodiode PD1 in the pixel unit P1, and the hexagonal effective pixel boundary B1, the following example is given: For example, the microlens unit corresponding to the upper surface of each pixel unit P1 can be a circular microlens unit with a radius of 2.5 μm ( Figure 2), and the side length of the hexagonal effective pixel boundary B1 of each pixel unit P1 can be 3μm. In addition, the side length of the hexagonal photodiode PD1 located at the center of the area surrounded by the hexagonal effective pixel boundary B1 can be 1.8μm. Through optical simulation analysis, it can be seen that the above-mentioned size matching relationship has an absorption efficiency of more than 90% for the incident light converged by the microlens unit by the pixel unit P1.

[0053] See also Figure 3 In other optional embodiments, taking into account the use of a hexagonal effective pixel shape, in order to match the hexagonal effective pixel boundary B1 and achieve the maximum effective photosensitivity area, we have also optimized the shape of the photodiode, and the photosensitivity area PD can be set to an octagonal photodiode PD2. Therefore, the octagonal photodiode PD2 located at the center of the hexagonal effective pixel shape can well receive the effective fluorescent signal transmitted by the light-guiding fiber in the optical fiber panel and then converged by the microlens on the surface of the pixel unit P1 (preferably, the upper surface of each pixel unit P1 corresponds to a microlens unit), and the octagonal photodiode PD2 has a photosensitivity area PD domain that is closer to a circle. Therefore, the application of the octagonal photodiode PD2 can not only achieve a better isolation effect between the pixel units P1, but also better receive the fluorescent signal converged by the microlens unit. In order to facilitate understanding of the size matching relationship between the microlens unit corresponding to the upper surface of the pixel unit P1, the octagonal photodiode PD2 in the pixel unit P1, and the hexagonal effective pixel boundary B1, an example is given below: For example, the microlens unit corresponding to the upper surface of each pixel unit P1 can be a circular microlens unit with a radius of 2.5 μm ( Figure 3 ), and the side length of the hexagonal effective pixel boundary B1 of each pixel unit P1 can be 3μm. In addition, the octagonal photodiode PD2 located at the center of the area surrounded by the hexagonal effective pixel boundary B1 includes four long sides and four short sides, wherein the length of the long side can be 1.6μm, and the length of the short side can be 1.13μm. Through optical simulation analysis, it can be seen that the above-mentioned size matching relationship has an absorption efficiency of more than 90% for the incident light converged by the microlens unit by the pixel unit P1.

[0054] Therefore, the pixel structure provided in this embodiment can detect fluorescent signals of different intensities and different chip manufacturing process conditions, and photodiodes of different shapes can be used according to actual conditions.

[0055] Among them, the first metal line L1 connects at least one odd-numbered row of pixel units P1 and at least one even-numbered row of pixel units P1 in the same column, and in the same column, the first metal line L1 is routed in the first side routing area K1 of the odd-numbered row of pixel units P1, and is routed in the second side routing area K2 of the even-numbered row of pixel units P1.

[0056] Therefore, the pixel structure provided in this embodiment is for the pixel units P1 arranged in a honeycomb shape (i.e., a honeycomb pixel array). In the same column, the metal wires are bent (or "snaked") between the pixel units P1 in odd rows and the pixel units P1 in adjacent even rows, so as to bypass the photosensitive area PD of each pixel unit P1 (e.g., Figure 1 As shown in the figure), the above wiring method can well connect multiple pixel units P1 in the column direction in the honeycomb pixel array, so that the pixel units P1 in different row positions connected thereto have basically similar topological structures relative to the first metal wire L1 of the column-oriented wiring, which can reduce the problem of poor uniformity caused by excessive layout differences. In addition, the structure of the first metal wire L1 bypassing the photosensitive area PD can improve or avoid the problem of metal blocking light, thereby increasing the effective photosensitive area of ​​the photodiode, and having better performance when detecting signals with large fluorescence intensity.

[0057] In an alternative embodiment, see Figures 4 to 6 , the first metal line L1 includes at least one straight line segment L101, at least one first oblique line segment L102 and / or at least one second oblique line segment L103. Among them, two adjacent straight line segments L101 of the first metal line L1 are connected by the first oblique line segment L102 or the second oblique line segment L103, and the first oblique line segment L102 of the first metal line L1 and the second oblique line segment L103 of the first metal line L1 have different inclination directions. Therefore, the first side routing area K1 of the pixel unit P1 of the odd-numbered rows and the second side routing area K2 of the pixel unit P1 of the even-numbered rows may include the straight line segment L101, the first oblique line segment L102 and / or the second oblique line segment L103 of the first metal line L1.

[0058] In an alternative embodiment, see Figures 4 to 6, the straight line segment L101 of the first metal line L1 is parallel to the column-direction vertical edge included in the effective pixel boundary B1 of the adjacent hexagon, the first oblique line segment L102 of the first metal line L1 is parallel to the first oblique edge included in the effective pixel boundary B1 of the adjacent hexagon, and the second oblique line segment L103 of the first metal line L1 is parallel to the second oblique edge included in the effective pixel boundary B1 of the adjacent hexagon, that is, the first metal line L1 is parallel to the boundary line of the effective pixel boundary B1 of the adjacent hexagon. Among them, the straight line segment L101 of the first metal line L1 forms a first corner with the first oblique line segment L102 of the adjacent first metal line L1, and forms a second corner with the second oblique line segment L103 of the adjacent first metal line L1, and the first corner and the second corner are both 120°.

[0059] In an optional embodiment, the first metal line L1 is parallel to the boundary line of the effective pixel boundary B1 of the adjacent hexagon and does not overlap therewith. This ensures that the first metal line L1 can be arranged vertically in a column when subsequently connected to other components (such as the source follower SF) vias, thereby reducing the impact of the first metal line L1 on other connected components.

[0060] In other optional implementations, the first metal line L1 is parallel to a boundary line of an adjacent hexagonal effective pixel boundary B1 and may overlap therewith.

[0061] In an alternative embodiment, see Figure 7 The pixel structure provided in this embodiment may further include a transfer transistor TX and a restart transistor RST, and the transfer transistor TX and the restart transistor RST are included in each pixel unit P1. Preferably, the transfer transistor TX and the restart transistor RST included in each pixel unit P1 are connected in sequence, wherein the transfer transistor TX is connected to the bottom of the column direction of the photosensitive area PD, and a floating node FD is included between the transfer transistor TX and the restart transistor RST.

[0062] In an alternative embodiment, see Figure 7 The gate of the transmission transistor TX is in the shape of an inverted trapezoid at the lower end of the column, and the restart transistor RST is connected to the short bottom side of the inverted trapezoid.

[0063] In an optional embodiment, the source end of the restart transistor RST and the floating node FD are multiplexed, and a linear arrangement structure is adopted (it can be understood that the source, drain and gate are arranged on a straight line perpendicular to the column direction) to minimize the area of ​​the active region at the floating node FD by avoiding turns, thereby reducing the parasitic capacitance at the floating node FD, and thus generating a larger voltage change when transmitting the same electrons, which is beneficial to the processing of the back-end transmission circuit and the signal recognition circuit, and reduces the influence of the internal noise of the circuit, and can improve the small-intensity light signal to ensure the accuracy of detection (for example, improving the small-intensity fluorescence signal, and even the detection accuracy in single-molecule fluorescence detection).

[0064] Therefore, the pixel structure provided in this embodiment is designed for optimizing the signal readout and signal conversion capabilities, and is designed for the transmission channel for storing electrons in the photosensitive area PD, and the position of the floating node FD where the electronic signal is converted into a voltage signal: in the gate terminal control of the input transistor, in order to match the change in the width of the active area of ​​the photosensitive area PD toward the floating node FD, the gate shape is optimized and an inverted trapezoidal structure is adopted to achieve a change in the width of the channel, so that the electrons in the PN junction in the photosensitive area PD can be better transmitted to the floating node FD area, and the residual electrons under high signal intensity are reduced to avoid erroneous information during the next readout. In addition, in the floating node FD area, the parasitic capacitance is reduced by optimizing and reducing its active area area, and a larger voltage change can be generated when the same electrons are transmitted, which is beneficial to the processing of the back-end transmission circuit and the signal recognition circuit, and reduces the influence of the internal noise of the circuit, and can improve the light signal of small intensity to ensure the accuracy of detection (for example, improving the detection accuracy of the fluorescence signal of small intensity, and even in the single molecule fluorescence detection).

[0065] In an alternative embodiment, see Figure 8 , the pixel structure provided in this embodiment may include at least two columns of pixel units P1, and also include a source follower SF. The source follower SF is arranged at the intersection of the three hexagonal pixel units P1. It can be understood that, on the source follower SF used to transmit the voltage signal of the floating node FD to the readout signal line, the layout of the source follower SF in this embodiment is also specially designed: since the source follower SF is in the first stage of signal readout amplification, the transistor input noise at this position will be directly superimposed with the photovoltage signal (such as the fluorescence voltage signal), so its noise has the greatest impact and needs to be suppressed the most. Therefore, in order to reduce the noise of the source follower SF, the source follower SF is placed at a position away from the photosensitive area PD (for example, the source follower SF is arranged at the intersection of the effective pixel boundary B1 of the three hexagonal pixel units P1, so as to realize that the source follower SF is placed at a position away from the photodiode), reducing the influence of the diffusion of electrons generated by the photosensitive area PD on the source follower SF, and reducing the influence of wiring and substrate on the source follower SF.

[0066] In an alternative embodiment, see Figure 8 , the source or drain of the source follower SF can be connected to the first metal line L1 (for example, when the first metal line L1 is a power signal transmission line, it is connected to the source of the source follower SF; or when the first metal line L1 is a data readout line, it is connected to the drain of the source follower SF), and the first metal line L1 covers the source or drain of the source follower SF, so that the noise caused by the electrons generated by the undesirable light incident on the source or drain of the source follower SF can be reduced. Preferably, a metal light blocking layer (not shown in the figure) is provided on the first metal line L1, and the metal light blocking layer is located above the source or drain of the source follower SF, so that the noise caused by the electrons generated by the undesirable light incident on the source or drain of the source follower SF can be further reduced.

[0067] In an alternative embodiment, see Figure 8 , the pixel structure provided in this embodiment may also include a driving signal line routed in the row direction, and the routing process of the driving signal line bypasses the source follower SF in the horizontal direction or on the same horizontal plane. Among them, the driving signal line may include at least one of the driving signal line DL1 of the transfer transistor, the driving signal line DL3 of the restart transistor, and the like. Therefore, in the pixel structure provided in this embodiment, on the metal routing in the row direction, the driving signal line DL1 of the transfer transistor, the driving signal line DL3 of the restart transistor, and the like bypass the source follower SF (it can be understood that they do not pass over the active area and the gate of the source follower SF), which can reduce the interference caused by the change in the strength of the driving voltage signal.

[0068] In an alternative embodiment, see Fig. 9 , each pixel unit P1 of the pixel structure provided in this embodiment may also include a dual conversion gain control transistor DCG, and the dual conversion gain control transistor DCG is connected between the transmission transistor TX and the restart transistor RST, and is located between the floating node FD and the restart transistor RST. Preferably, the conversion gain control transistor is multiplexed with the source end of the floating node FD and the restart transistor RST, and a linear arrangement structure is adopted to reduce the area of ​​the active area at the floating node FD. In addition, see Fig.10 When the driving signal line DL2 of the dual conversion gain control transistor is routed in the row direction, the routing of the driving signal line DL1 of the transmission transistor, the driving signal line DL3 of the restart transistor, etc. can be referred to, and will not be repeated here.

[0069] In an alternative embodiment, see Fig.11The pixel structure provided in this embodiment may further include a row selection transistor RS, which is arranged next to the source follower SF. Preferably, the row selection transistor RS and the source follower SF share a source. Fig.11 When the driving signal line DL4 of the row selection transistor is routed in the row direction, the routing of the driving signal line DL1 of the transmission transistor, the driving signal line of the restart transistor DL3 and the like may be referred to, and will not be described in detail herein.

[0070] The pixel structure provided in the first embodiment of the present application includes a plurality of pixel units P1 and a first metal line L1; the plurality of pixel units P1 are arranged in a honeycomb shape, and the column positions of the pixel units P1 in odd rows are different from those of the pixel units P1 in adjacent even rows; wherein each pixel unit P1 is hexagonal, and each pixel unit P1 includes a photosensitive area PD and a first side wiring area K1 and a second side wiring area K2 that are symmetrical in the column direction; the first metal line L1 connects at least one pixel unit P1 in an odd row and at least one pixel unit P1 in an even row in the same column, and in the same column, the first metal line L1 is routed in the first side wiring area K1 of the pixel units P1 in the odd rows, and is routed in the second side wiring area K2 of the pixel units P1 in the even rows. Therefore, the pixel structure provided in the first embodiment of the present application, for the pixel units P1 arranged in a honeycomb shape, allows the metal lines to be bent and routed between the pixel units P1 in odd rows and the pixel units P1 in adjacent even rows in the same column, so as to bypass the photosensitive area PD of each pixel unit P1. Therefore, the pixel structure provided in the first embodiment of the present application can improve or avoid the problem of metal light blocking in the photosensitive area PD of the pixel unit P1, thereby achieving the purpose of improving the detection effect of the image sensor.

[0071] Second embodiment:

[0072] In order to clearly describe the pixel structure provided by the second embodiment of the present application, see Figures 1 to 15 .

[0073] See also Figure 1 and Fig.12 The pixel structure provided in the second embodiment of the present application differs from the pixel structure provided in the first embodiment of the present application in that it further includes a second metal line L2. Preferably, the first metal line L1 can be a power signal transmission line, and the second metal line L2 can be a data readout line.

[0074] See also Fig.12 In the pixel structure provided in the second embodiment of the present application, the first metal line L1 connects at least one pixel unit P1 of an odd row and at least one pixel unit P1 of an even row in the same column, and in the same column, the first metal line L1 is routed in the first side routing area K1 of the pixel unit P1 of the odd row, and is routed in the second side routing area K2 of the pixel unit P1 of the even row.

[0075] See also Fig.12 In the pixel structure provided in the second embodiment of the present application, the second metal line L2 connects at least one odd-numbered pixel unit P1 and at least one even-numbered pixel unit P1 in the same column, and in the same column, the second metal line L2 is routed in the second side routing area K2 of the odd-numbered pixel unit P1, and is routed in the first side routing area K1 of the even-numbered pixel unit P1.

[0076] Therefore, the pixel structure provided in this embodiment is for the pixel units P1 arranged in a honeycomb shape (i.e., a honeycomb pixel array). In the same column, the first metal line L1 and the second metal line L2 are respectively bent and routed (or "snaked") between the pixel units P1 in the odd rows and the pixel units P1 in the adjacent even rows, so as to bypass the photosensitive area PD of each pixel unit P1 (e.g., Fig.12 As shown in the figure), the above wiring method can well connect multiple pixel units P1 in the column direction in the honeycomb pixel array, so that the pixel units P1 in different row positions connected thereto have basically similar topological structures relative to the first metal wire L1 and the second metal wire L2 of the column-oriented wiring, which can reduce the problem of poor uniformity caused by excessive layout differences. In addition, the structure of the first metal wire L1 and the structure of the second metal wire L2 that bypass the photosensitive area PD can improve or avoid the problem of metal blocking light, thereby increasing the effective photosensitive area of ​​the photodiode, and having better performance when detecting signals with large fluorescence intensity.

[0077] In an optional embodiment, the second metal line L2 is symmetrical to the adjacent first metal line L1.

[0078] In an optional embodiment, the second metal line L2 includes at least one straight line segment, at least one first oblique line segment and / or at least one second oblique line segment. Two adjacent straight line segments of the second metal line L2 are connected by the first oblique line segment or the second oblique line segment, and the first oblique line segment of the second metal line L2 and the second oblique line segment of the second metal line L2 have different inclination directions. Therefore, the second side routing area K2 of the pixel unit P1 of the odd-numbered rows and the first side routing area K1 of the pixel unit P1 of the even-numbered rows both include the straight line segment, the first oblique line segment and / or the second oblique line segment of the second metal line L2.

[0079] In an optional embodiment, the straight line segment of the second metal line L2 is parallel to the axial vertical side included in the effective pixel boundary B1 of the adjacent hexagon, the first oblique line segment of the second metal line L2 is parallel to the first oblique side included in the effective pixel boundary B1 of the adjacent hexagon, and the second oblique line segment of the second metal line L2 is parallel to the second oblique side included in the effective pixel boundary B1 of the adjacent hexagon, that is, the second metal line L2 is parallel to the boundary line of the effective pixel boundary B1 of the adjacent hexagon. The straight line segment of the second metal line L2 forms a first corner with the first oblique line segment of the adjacent second metal line L2, and forms a second corner with the second oblique line segment of the adjacent second metal line L2, and the first corner and the second corner are both 120°.

[0080] In an optional embodiment, the second metal line L2 is parallel to the boundary line of the effective pixel boundary B1 of the adjacent hexagon and does not overlap therewith. This ensures that the second metal line L2 can be arranged vertically in a column when subsequently connected to other components (such as the source follower SF) vias, thereby reducing the impact of the second metal line L2 on other connected components.

[0081] In other optional embodiments, the second metal line L2 is parallel to a boundary line of an adjacent hexagonal effective pixel boundary B1 and may overlap with the boundary line.

[0082] In an optional implementation, the pixel units P1 of the odd-numbered rows and the pixel units P1 of the even-numbered rows connected by the second metal wire L2 and the first metal wire L1 have similar or identical topological structures.

[0083] In an alternative embodiment, see Figures 13 to 15 , the second metal line L2 is connected to the drain of the source follower SF and covers the drain of the source follower SF, and a metal light blocking layer (not shown in the figure) is provided on the second metal line L2, and the metal light blocking layer is located above the drain of the source follower SF. In addition, the first metal line L1 is connected to the source of the source follower SF and covers the source of the source follower SF, and a metal light blocking layer is provided on the first metal line L1, and the metal light blocking layer is located above the source of the source follower SF. Therefore, the metal wiring (power signal line and data readout line) in the column direction of the pixel structure provided in this embodiment needs to connect the source and drain of the source follower SF, and a metal light blocking layer is provided at the upper position, and the source and drain are shielded by the vertical metal, so as to reduce the electron introduction noise generated by various undesirable light injection into the active area (such as the source and drain of the source follower SF).

[0084] In an optional embodiment, in the pixel structure provided in the second embodiment of the present application, the specific implementation methods and beneficial effects of multiple pixel units P1, microlens units, first metal lines L1, transfer transistors TX, restart transistors RST, dual conversion gain control transistors DCG, source followers SF, row selection transistors RS, drive signal lines, etc. can refer to the pixel structure provided in the first embodiment of the present application and will not be repeated here.

[0085] The pixel structure provided in the first embodiment of the present application includes a plurality of pixel units P1, a first metal line L1 and a second metal line L2; wherein the plurality of pixel units P1 are arranged in a honeycomb shape, and the pixel units P1 in odd rows are at different column positions from the pixel units P1 in adjacent even rows; wherein each pixel unit P1 is a hexagon, and each pixel unit P1 includes a photosensitive area PD and a first side wiring area K1 and a second side wiring area K2 that are symmetrical in the column direction; the first metal line L1 connects at least one pixel unit P1 in an odd row in the same column and At least one even-numbered row of pixel units P1, and in the same column, the first metal line L1 is routed in the first side routing area K1 of the odd-numbered row of pixel units P1, and is routed in the second side routing area K2 of the even-numbered row of pixel units P1; wherein the second metal line L2 connects at least one odd-numbered row of pixel units P1 and at least one even-numbered row of pixel units P1 in the same column, and in the same column, the second metal line L2 is routed in the second side routing area K2 of the odd-numbered row of pixel units P1, and is routed in the first side routing area K1 of the even-numbered row of pixel units P1. Therefore, the pixel structure provided in the second embodiment of the present application, for the pixel units P1 arranged in a honeycomb shape, makes the first metal wire L1 and the second metal wire L2 bend and route between the pixel units P1 in odd rows and the pixel units P1 in adjacent even rows in the same column, so as to bypass the photosensitive area PD of each pixel unit P1. Therefore, the pixel structure provided in the second embodiment of the present application can improve or avoid the problem of metal light blocking in the photosensitive area PD of the pixel unit P1, thereby achieving the purpose of improving the detection effect of the image sensor.

[0086] In addition, the embodiment of the present application further provides an image sensor, which includes the pixel structure described in the first embodiment or the second embodiment. Therefore, the image sensor provided by the embodiment of the present application can improve or avoid the metal light blocking problem of the photosensitive area PD of the pixel unit P1, thereby achieving the purpose of improving the detection effect.

[0087] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0089] It should be understood that, although the terms first, second, third, etc. may be used to describe various elements in this article, these elements should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this article, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element. Depending on the context, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising", "including" indicate that there are described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". An exception to this definition will occur only when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

[0090] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A pixel structure, characterized in that: comprising a plurality of pixel units and a first metal line; The plurality of pixel units are arranged in a honeycomb shape, and the pixel units in odd-numbered rows are located at different column positions from the pixel units in adjacent even-numbered rows; Each pixel unit is hexagonal, and each pixel unit includes a photosensitive area and a first side wiring area and a second side wiring area that are symmetrical in the column direction; The first metal line connects at least one odd-numbered row of pixel units and at least one even-numbered row of pixel units in the same column, and in the same column, the first metal line is routed in a first side routing area of ​​the pixel units in the odd-numbered rows and in a second side routing area of ​​the pixel units in the even-numbered rows, and the first metal line is bent and routed between the pixel units in two adjacent rows to bypass the photosensitive area of ​​each pixel unit.

2. The pixel structure according to claim 1, characterized in that: The first metal line comprises at least one straight line segment, at least one first oblique line segment and / or at least one second oblique line segment; Wherein, two adjacent straight line segments of the first metal wire are connected by a first oblique line segment or a second oblique line segment, and the first oblique line segment of the first metal wire and the second oblique line segment of the first metal wire have different inclination directions; The first side wiring area of ​​the pixel units in the odd rows and the second side wiring area of ​​the pixel units in the even rows both include straight line segments, first oblique line segments and / or second oblique line segments of the first metal wire.

3. The pixel structure according to claim 2, characterized in that: Each pixel unit includes a hexagonal effective pixel boundary, and the hexagonal effective pixel boundary includes a column-direction vertical edge, a first inclined edge, and a second inclined edge; The straight line segment of the first metal line is parallel to the adjacent column-direction vertical edge, the first oblique line segment of the first metal line is parallel to the adjacent first inclined edge, and the second oblique line segment of the first metal line is parallel to the adjacent second inclined edge; The straight line segment of the first metal wire forms a first corner with the first oblique line segment of the adjacent first metal wire, and forms a second corner with the second oblique line segment of the adjacent first metal wire, and both the first corner and the second corner are 120°.

4. The pixel structure according to claim 1, wherein: Also comprising a second metal wire; The second metal line connects at least one odd-numbered row of pixel units and at least one even-numbered row of pixel units in the same column, and in the same column, the second metal line is routed in the second side routing area of ​​the pixel units in the odd-numbered rows and in the first side routing area of ​​the pixel units in the even-numbered rows.

5. The pixel structure according to claim 4, characterized in that: The second metal line is symmetrical to the adjacent first metal line.

6. The pixel structure according to claim 4, characterized in that: The first metal line is a power signal transmission line, and the second metal line is a data readout line.

7. The pixel structure according to any one of claims 1 to 6, characterized in that: The photosensitive area of ​​each pixel unit is a photodiode located at the center thereof; The photodiode includes one of a hexagonal photodiode, an octagonal photodiode, and a circular photodiode.

8. The pixel structure according to claim 7, characterized in that: The side length of the hexagonal effective pixel boundary of each pixel unit is 3 μm.

9. The pixel structure according to claim 7, wherein: The side lengths of the hexagonal photodiodes are all 1.8 μm; or, The octagonal photodiode includes four long sides and four short sides, wherein the length of the long sides is 1.6 μm, and the length of the short sides is 1.13 μm.

10. The pixel structure according to any one of claims 1 to 6, characterized in that: Each pixel unit further includes a transmission transistor and a restart transistor connected in sequence; The transmission transistor is connected to one side of the photosensitive region at the bottom of the column, and a floating node is included between the transmission transistor and the restart transistor.

11. The pixel structure according to claim 10, wherein: The gate of the transfer transistor is in an inverted trapezoidal shape at the lower end of the column; The restart transistor is connected to the short bottom side of the inverted trapezoid.

12. The pixel structure according to claim 10, wherein: The floating node is multiplexed with the source end of the restart transistor, and a linear arrangement structure is adopted to reduce the area of ​​the active region at the floating node.

13. The pixel structure according to claim 10, characterized in that: A dual conversion gain control transistor is also connected between the transmission transistor and the restart transistor; The dual conversion gain control transistor is multiplexed with the floating node and the source end of the restart transistor, and a linear arrangement structure is adopted to reduce the area of ​​the active region at the floating node.

14. The pixel structure according to claim 10, wherein: comprising at least two columns of pixel units, and also comprising a source follower; The source follower is arranged at the intersection of three hexagonal pixel units.

15. The pixel structure according to claim 14, wherein: It also includes a driving signal line routed in a row direction, and the routing process of the driving signal line bypasses the source follower in a horizontal direction; The driving signal line includes at least one of a driving signal line of the transmission transistor, a driving signal line of the dual conversion gain control transistor, and a driving signal line of the restart transistor.

16. The pixel structure according to claim 15, characterized in that: A row selection transistor is provided next to the source follower; The row selection transistor shares a source with the source follower; The driving signal lines also include driving signal lines for the row selection transistors.

17. The pixel structure according to claim 14, wherein: The first metal line is connected to the source of the source follower and covers the source of the source follower, and a metal light blocking layer is provided on the first metal line, and the metal light blocking layer is located above the source of the source follower; and / or, The second metal line is connected to the drain of the source follower and covers the drain of the source follower. A metal light blocking layer is arranged on the second metal line. The metal light blocking layer is located above the drain of the source follower.

18. An image sensor, characterized in that: Comprising the pixel structure as claimed in any one of claims 1 to 17.

Images