Image sensor and electronic device

Abstract

The utility model discloses an image sensor and electronic equipment, image sensor includes circuit connection layer, optical structure layer and semiconductor structure layer, and semiconductor structure layer has the array distribution's photosensitive pixel area and the partition structure that will multiple photosensitive pixel area mutually interval apart and penetrate semiconductor structure layer in, be equipped with the segmentation structure that will photosensitive pixel area divide into at least two subareas in each photosensitive pixel area, and the segmentation structure is located semiconductor structure layer far away from the one side of circuit connection layer, and the height of segmentation structure is less than the height of partition structure. Through setting up the segmentation structure that will photosensitive pixel area divide into multiple subareas in each photosensitive pixel area, and the segmentation structure is located semiconductor structure layer close to the one side of optical structure layer and the height is less than the height of partition structure, utilize small pixel distribution effective contribution FWC, make each small pixel contribution's FWC sum greater than the FWC of large area photosensitive pixel area contribution before unsegmentation.

Description

Technical Field

[0001] This utility model relates to the field of image sensor technology, and in particular to an image sensor and electronic device. Background Technology

[0002] An image sensor is a device that converts light signals into electrical signals. Commercially available image sensor chips typically fall into two main categories: charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) image sensor chips. Compared to traditional CCD sensors, CMOS image sensors offer advantages such as low power consumption, low cost, and compatibility with CMOS processes, leading to their increasingly widespread application. Currently, CMOS image sensors are used not only in consumer electronics, such as miniature digital cameras (DSCs), mobile phone cameras, camcorders, and digital SLRs (DSLRs), but also in automotive electronics, surveillance, biotechnology, and medicine.

[0003] The pixel unit of a CMOS image sensor is the core component that enables the sensor to sense light. The most commonly used pixel unit is an active pixel structure that includes a photodiode and multiple transistors. In these devices, the photodiode is the photosensitive unit, which collects light and performs photoelectric conversion, while the other MOS transistors are control units, mainly responsible for controlling the selection, reset, signal amplification, and readout of the photodiode.

[0004] When pixel size is small, the full well capacity (FWC) decreases due to limited area. Lower FWC leads to lower dynamic range and lower signal-to-noise ratio (SNR) due to strong light conditions. To improve FWC, existing technologies use larger pixels. However, while the pixel area increases, the increase in FWC is typically much smaller than the increase in area. This is because the doping concentration distribution created by the aperture area of ​​a mask is higher in the center and lower at the edges. For larger pixels, this difference between the center and edges becomes greater. Since the potential in the center of the pixel has a maximum limit, the increased pixel area is not effectively utilized to contribute to FWC. Furthermore, pixel transfer is also an important issue that needs to be considered in this field. Utility Model Content

[0005] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide an image sensor and electronic device to solve the problem of low utilization of full-well capacity of large-size pixels in the existing technology.

[0006] The objective of this utility model is achieved through the following technical solution: This invention provides an image sensor, including a circuit connection layer, an optical structure layer, and a semiconductor structure layer. The semiconductor structure layer has photosensitive pixel areas distributed in an array and a partition structure that separates multiple photosensitive pixel areas and penetrates the semiconductor structure layer. Each photosensitive pixel area has a partition structure that divides the photosensitive pixel area into at least two sub-regions. The partition structure is located on the side of the semiconductor structure layer away from the circuit connection layer, and the height of the partition structure is less than the height of the separation structure.

[0007] Furthermore, each photosensitive pixel region includes a deep photosensitive region and a shallow photosensitive region stacked on top of each other. The deep photosensitive region is located on the side of the semiconductor structure layer away from the circuit connection layer, and the shallow photosensitive region is located on the side of the semiconductor structure layer close to the circuit connection layer. The segmentation structure divides the deep photosensitive region into multiple sub-regions, and a charge transport channel region is configured in the shallow photosensitive region based on the segmentation structure. The charge transport channel region is located on the side of the semiconductor structure layer close to the circuit connection layer.

[0008] Furthermore, the segmentation structure has a transmission depth between itself and the surface of the semiconductor structure layer near the optical structure layer, and the photosensitive pixel region has a charge transport channel. The transmission depth at different locations is the same or has a negative correlation with the distance between the location and the charge transport channel.

[0009] Furthermore, the height of the segmented structure is equal to the height of the deep photosensitive region; and / or, the doping concentration of the deep photosensitive region is the same as or different from the doping concentration of the shallow photosensitive region.

[0010] Furthermore, the photosensitive pixel area is a first type of conductive semiconductor, and the separator structure and the segmentation structure are second type of conductive semiconductors, which are different from the first type of conductive semiconductor.

[0011] Furthermore, the first conductive semiconductor is an n-type semiconductor, and the second conductive semiconductor is a p-type semiconductor.

[0012] Furthermore, the doping concentrations of the partition structure and the segmentation structure may be the same or different; and / or, the segmentation structure includes a plurality of sub-segmentation structures along a normal direction perpendicular to the surface of the semiconductor structure layer, and the doping concentration of each sub-segmentation structure decreases toward the circuit connection layer.

[0013] Furthermore, the segmentation structure includes a first doped region and a second doped region stacked on top of each other, wherein the doping concentrations of the first doped region and the second doped region are different; or, the segmentation structure includes a first doped region and a second doped region stacked on top of each other, wherein one of the first doped region and the second doped region has the same doping concentration as the segmentation structure, and the other has a different doping concentration than the segmentation structure.

[0014] Furthermore, the segmentation structure divides the photosensitive pixel region into N 2 There are 2 subregions, where N is an integer greater than or equal to 2.

[0015] Furthermore, the partition structure includes a grooved isolation structure that penetrates the partition structure.

[0016] Furthermore, the segmentation structure includes a unit deep trench isolation, the semiconductor structure layer is located between the circuit connection layer and the optical structure layer, the unit deep trench isolation is located on the side of the segmentation structure closer to the optical structure layer, and the height of the unit deep trench isolation is less than the height of the segmentation structure.

[0017] Furthermore, the circuit connection layer is provided with transmission transistors, and each transmission transistor corresponds to a photosensitive pixel area.

[0018] Furthermore, the photosensitive pixel area corresponds one-to-one with the floating diffusion node working area; or, at least two photosensitive pixel areas correspond to one floating diffusion node working area, wherein when four photosensitive pixel areas correspond to one floating diffusion node working area, the charge transport path of each photosensitive pixel area is symmetrical with respect to the center of the floating diffusion node working area.

[0019] This application also provides an electronic device, including the image sensor described above.

[0020] The beneficial effects of this invention are as follows: By setting a segmentation structure in each photosensitive pixel area, the segmentation structure divides the photosensitive pixel area into multiple sub-regions. Furthermore, the segmentation structure is located on the side of the semiconductor structure layer away from the circuit connection layer and its height is less than the height of the dividing structure. This divides the photosensitive pixel area into multiple small pixels within a certain depth range. For each small pixel, the distribution of small pixels can effectively contribute to the field of view (FWC), making the sum of the FWC contributed by each small pixel greater than the FWC contributed by the large photosensitive pixel area before segmentation. The photosensitive pixel area near the circuit connection layer is not segmented by the segmentation structure and remains connected, ensuring smooth transmission to the transmission transistor. Therefore, only one transmission transistor is needed for each photosensitive pixel area. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the basic structure of an image sensor system.

[0022] Figure 2 This is a schematic diagram of the pixel circuit of an image sensor.

[0023] Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 1 of this utility model.

[0024] Figure 4 This is a schematic diagram of the cross-sectional structure of the image sensor in the shallow photosensitive area in Embodiment 1 of this utility model.

[0025] Figure 5 This is a schematic diagram of the cross-sectional structure of the image sensor in the deep photosensitive area in Embodiment 1 of this utility model.

[0026] Figures 6a-6e This is a flowchart illustrating the structure of four methods for manufacturing the image sensor in Embodiment 1 of this utility model.

[0027] Figure 7 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 2 of this utility model.

[0028] Figure 8 This is a schematic diagram of the cross-sectional structure of the image sensor in the deep photosensitive area in Embodiment 2 of this utility model.

[0029] Figure 9 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 3 of this utility model.

[0030] Figure 10 This is a flowchart illustrating the fabrication method of the image sensor in Embodiment 3 of this utility model.

[0031] Figure 11 This is one of the schematic diagrams of the longitudinal section structure of the image sensor in Embodiment 4 of this utility model.

[0032] Figure 12 This is the second schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 4 of this utility model.

[0033] Figure 13 This is the third schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 4 of this utility model. Detailed Implementation

[0034] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation methods, structures, features, and effects of the image sensor and electronic device proposed according to this utility model: Figure 1This is a basic circuit diagram of an image sensor. (For example...) Figure 1 As shown, the image sensor 100 includes a readout circuit 104 and a control circuit 108 connected to the pixel array 102. A functional logic circuit 106 is connected to the readout circuit 104 to perform logic control on the reading of the pixel array. The readout circuit 104 and the control circuit 108 are connected to the status register 112 to realize the readout control of the pixel array 102. The pixel array 101 includes multiple pixel units arranged in rows (R1, R2, R3…Ry) and columns (C1, C2, C3…Cx). The pixel signals output by the pixel array 102 are output to the readout circuit 104 via the column lines.

[0035] In one embodiment, after each pixel unit acquires image data, the image data is read out by a readout circuit 104 specifying the readout mode in the status register 112, and then transmitted to the functional logic circuit 106. In specific applications, the readout circuit 104 may include an analog-to-digital converter (ADC) circuit, an amplifier circuit, and others. In some application embodiments, the status register 112 may include a programmed selection system to determine whether the readout system reads out in a rolling shutter mode or a global shutter mode. The functional logic circuit 106 may store only image data or image data applied or processed by image effects. In one application example, the readout circuit 104 may read out one row of image data at a time along the readout column lines, or it may read out image data in various other ways. The operation of the control circuit 108 can be determined by the current setting of the status register 112. For example, the control circuit 108 generates a shutter signal to control image acquisition. In some application examples, this shutter signal may be a global shutter signal that causes all pixels of the pixel array 102 to simultaneously acquire their image data through a single acquisition window. In some other applications, this shutter signal can be a rolling exposure signal, with each pixel row being read continuously through an acquisition window.

[0036] Figure 2 This is a schematic diagram of the pixel circuitry of an image sensor, which can show the connection diagram of a transistor in the image sensor. For example... Figure 2As shown, each sensor pixel circuit 200 includes a light sensing element 210 (e.g., a photodiode, PD) and a pixel support circuit 211. The photodiode 210 may be a buried photodiode used in current image sensors. In one application example, the pixel support circuit 211 includes a reset transistor (RST) 220, a source follower (SF) transistor 225, and a row select transistor (RS) 230, connected to a transfer transistor (TX) 215 and the photodiode 210 as shown. In another application example, not shown, the pixel support circuit 211 includes a reset transistor 220, a source follower transistor 225, and a row select transistor 230 disposed on a circuit chip, connected to the photodiode 210 in another chip based on the transfer transistor 215. During operation, the photocharge generated by the light sensing element 210 responds to incident light during exposure. The transfer transistor 215 is connected to a transfer signal that controls the transfer transistor 215 to transfer the charge accumulated in the photodiode 210 to the floating diffusion region (FD) 217. In one embodiment, the transfer transistor 215 may be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). A reset transistor 220 is connected between VDD and the floating diffusion region 217, responding to a reset signal RST to reset the sensor pixel circuitry 200 (e.g., discharging or charging the floating diffusion region 217 and photodiode 210 to the current voltage). The floating diffusion region 217 is connected to the gate of the source follower transistor 225. The source follower transistor 225 is connected between VDD and the row select transistor 230 to respond to and output the potential of the floating diffusion region FD 217. The row select transistor 230 is connected from the source follower transistor 225 to the pixel circuitry output to the readout column, or bit line 235, in response to a row select control signal.

[0037] [Example 1] Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 1 of this utility model. Figure 4 This is a schematic diagram of the cross-sectional structure of the image sensor in the shallow photosensitive area in Embodiment 1 of this utility model. Figure 5 This is a schematic diagram of the cross-sectional structure of the image sensor in the deep photosensitive area in Embodiment 1 of this utility model.

[0038] like Figures 3 to 5As shown, an image sensor provided in Embodiment 1 of this utility model includes a circuit connection layer 300, an optical structure layer 500, and a semiconductor structure layer 400. In this embodiment, a back-illuminated sensor is used as an example for illustration. Other implementations may also be front-illuminated image sensors. In this example, the semiconductor structure layer 400 is located between the circuit connection layer 300 and the optical structure layer 500. The semiconductor structure layer 400 has photosensitive pixel areas 410 arranged in an array and a partition structure 420 that separates the multiple photosensitive pixel areas 410 from each other and penetrates the semiconductor structure layer 400. The partition structure 420 is a frame structure that separates the multiple photosensitive pixel areas 410 from each other. A photosensitive element (photodiode, PD) is provided in the photosensitive pixel area 21. Each photosensitive pixel area 410 is provided with a segmentation structure 430 that divides the photosensitive pixel area 410 into at least two sub-regions. The segmentation structure 430 is located on the side of the semiconductor structure layer 400 away from the circuit connection layer 300. In this example, it is located on the side closer to the optical structure layer 500. The height of the segmentation structure 430 is less than the height of the partition structure 420, that is, the height of the segmentation structure 430 is less than the height of the photosensitive pixel area 410. The segmentation structure 430 only divides the area of ​​the photosensitive pixel area 410 on the side closer to the optical structure layer 500 into multiple sub-regions.

[0039] By setting a segmentation structure 430 in the photosensitive pixel area 410, the segmentation structure 430 is used to divide the photosensitive pixel area 410 into multiple sub-regions. The segmentation structure 430 is located on the side of the semiconductor structure layer 400 away from the circuit connection layer 300 and its height is less than the height of the partition structure 420. This divides the photosensitive pixel area 410 into multiple small pixels (i.e., sub-regions) within a certain depth range. The number of segments can be set according to actual needs. For each small pixel, the distribution of small pixels can effectively contribute to the field of view (FWC), making the sum of the FWC contributed by each small pixel greater than the FWC contributed by the large area of ​​the photosensitive pixel area 410 before segmentation. The side of the photosensitive pixel area 410 closest to the circuit connection layer 300 is not segmented by the segmentation structure 430 and is connected together, which facilitates smooth transmission to the transmission transistor (TX) 310. Therefore, only one transmission transistor 310 is needed for one photosensitive pixel area 410; that is, multiple sub-regions within one photosensitive pixel area 410 share one transmission transistor 310.

[0040] In this embodiment, each photosensitive pixel area 410 includes a deep photosensitive area 411 and a shallow photosensitive area 412 stacked on top of each other. The deep photosensitive area 411 is located on the side of the semiconductor structure layer 400 away from the circuit connection layer 300, and the shallow photosensitive area 412 is located on the side of the semiconductor structure layer 400 closer to the circuit connection layer 300. The segmentation structure 430 divides the deep photosensitive area 411 into multiple sub-regions, while the shallow photosensitive areas 412 within a photosensitive pixel area 410 are interconnected. The height of the segmentation structure 430 is equal to the height of the deep photosensitive area 411. The heights of the deep photosensitive area 411 and the shallow photosensitive area 412 can be set according to actual needs; the height of the deep photosensitive area 411 can be equal to or greater than the height of the shallow photosensitive area 412. Based on the segmentation structure 430, a charge transport channel region is configured in the shallow photosensitive area 412. The charge transport channel region is located on the side of the semiconductor structure layer 400 near the circuit connection layer 300. This facilitates the transfer of electrons in the segmented sub-regions of the deep photosensitive area based on the formed charge transport channel, thereby promoting electron transfer in the overall photosensitive area.

[0041] Furthermore, the photosensitive pixel region 410 is a first conductivity type semiconductor, and the separator structure 420 and the segmentation structure 430 are second conductivity type semiconductors, which are different from the first conductivity type semiconductor. In this embodiment, the first conductivity type semiconductor is an n-type semiconductor, and the second conductivity type semiconductor is a p-type semiconductor, that is, p-doping is performed on one side of the photosensitive pixel region 410 of the n-type semiconductor, thereby forming the segmentation structure 430. In one implementation, the segmentation structure 430 includes multiple sub-segmentation structures along the normal direction perpendicular to the surface of the semiconductor structure layer 400, and the doping concentration of each sub-segmentation structure decreases towards the circuit connection layer 300. Among them, the doping concentrations of the separator structure 420 and the segmentation structure 430 are different. The doping concentrations of the separator structure 420 and the segmentation structure 430 can be set according to actual needs. The doping concentration of the separator structure 420 can be greater than the doping concentration of the segmentation structure 430, or it can be less than the doping concentration of the segmentation structure 430. Of course, in other implementations, the doping concentrations of the separator structure 420 and the segmentation structure 430 can also be the same. In one implementation, the doping concentration of the segmentation structure 430 can be set to have a concentration gradient. That is, the segmentation structure 430 includes multiple sub-segmentation structures along the normal direction perpendicular to the surface of the semiconductor structure layer 400. For example, this can be achieved by additional doping. The concentration distribution at different depths can effectively improve the vertical transmission problem of the photoelectric conversion element. For example, the photosensitive doped region 410 is n-type and the segmentation structure 430 is p-type. The concentration of the segmentation structure is smaller in the direction close to the transmission transistor. Alternatively, the concentration can be the same within a certain distance range in depth, forming a trend of gradually decreasing doping concentration, which is beneficial to photoelectric transmission and improves imaging quality.

[0042] As an example, there is a transmission depth between the segmentation structure 430 and the surface of the semiconductor structure layer 400 away from the circuit connection layer 300. That is, the charge transport channel region formed based on the segmentation structure has the aforementioned transmission depth, and the photosensitive pixel region 410 has a charge transport channel. The transmission depth corresponding to different positions of the segmentation structure 430 is the same or has a negative correlation with the distance between that position and the charge transport channel. The negative correlation between the transmission depth corresponding to different positions and the distance between that position and the charge transport channel can be that the distance between the projection of that position onto the surface of the semiconductor structure layer 400 away from the circuit connection layer 300 and the projection of the transport transistor onto the same surface is negatively correlated. This negative correlation could mean that the transmission depth gradually decreases as the distance decreases, or that the transmission depth is the same within a certain range of that distance, resulting in a gradually decreasing trend. Based on the above configuration, it is beneficial to promote electron transport in the deep segmented areas and improve the overall transport efficiency under the design of the segmentation structure in this application.

[0043] Furthermore, the segmentation structure 430 divides the photosensitive pixel area 410 into N 2 There are several sub-regions, where N is an integer greater than or equal to 2. In this embodiment, as shown... Figure 5 As shown, the top view of the segmentation structure 430 is a cross-shaped structure, thereby dividing the photosensitive pixel area 410 into four sub-regions. Optionally, the segmentation structure 430 divides the photosensitive pixel area 410 into multiple sub-regions of equal area, so that each sub-region can fully contribute to FWC and can complete charge transfer as needed.

[0044] In this embodiment, the circuit connection layer 300 includes a transmission transistor 310, which corresponds one-to-one with the photosensitive pixel area 410. The photosensitive pixel area 410 is connected to the transmission transistor 310, thereby transferring the charge accumulated in the photosensitive pixel area 410 to the floating diffusion region (FD). Of course, the circuit connection layer 300 also has other transistors, such as a reset transistor (RST), a source follower (SF) transistor, and a row select transistor (RS), to form a pixel support circuit.

[0045] As an example, each photosensitive pixel area 410 corresponds one-to-one with a floating diffusion node working area, or at least two photosensitive pixel areas 410 correspond to one floating diffusion node working area. In one implementation, when four photosensitive pixel areas correspond to one floating diffusion node working area, the charge transport path of each photosensitive pixel area 410 is symmetrical with respect to the center of the floating diffusion node working area. Specifically, the four photosensitive pixel areas 410 have a central control area at their center, and the floating diffusion node working area is set in the central control area. In a further example, the floating diffusion node working area includes two floating diffusion nodes. Furthermore, a source follower transistor is arranged in the central control area, and the two floating diffusion nodes are distributed on both sides of the source follower transistor and are shared by two different photosensitive pixel areas 410 respectively. Each photosensitive pixel area 410 corresponds to a transmission transistor, which is located at the corner of the photosensitive pixel area 410 and arranged around the central control area. In this example, since each photosensitive pixel area 410 corresponds one-to-one with a transmission transistor, all four photosensitive pixel areas 410 have a transmission path toward the central control area. That is, the charge transmission path of each photosensitive pixel area 410 is symmetrical with respect to the center of the floating diffusion node working area, thereby improving the signal consistency acquired by different photosensitive pixel areas 410.

[0046] The optical structure layer 500 includes a color filter layer 510 and a microlens array structure 520. The color filter layer 510 includes red (R), green (G) and blue (B) color filter layers arranged in an array. Each color filter layer 510 corresponds to a photosensitive pixel area 410. The microlens array structure 520 has a light-focusing effect, which concentrates light onto the photosensitive pixel area 410.

[0047] Figures 6a-6e This is a flowchart illustrating the structure of five manufacturing methods for the image sensor in Embodiment 1 of this utility model. For example... Figure 6a As shown, one of the manufacturing methods includes: A semiconductor substrate is provided. First, a first mask is used as a shield to perform a first n-doping on the semiconductor substrate. The depth of the first n-doping is controlled to form a deep photosensitive region 411. The semiconductor substrate is made of materials such as silicon or germanium. In some embodiments, the semiconductor substrate may also include at least one or more other photosensitive materials, such as silicon-germanium, silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, indium, antimony, semiconductor-on-insulator, or combinations thereof.

[0048] A second mask is then used as a shield to perform a second n-doping on the semiconductor substrate. The depth of the second n-doping is controlled to form a shallow photosensitive area 412. That is, the photosensitive pixel area 410 is formed by two n-doping processes at different depths.

[0049] A third mask is used as a shield to perform the first p-doping on the semiconductor substrate, which penetrates the semiconductor substrate, thereby forming a separation structure 420. The separation structure 420 is used to separate multiple photosensitive pixel areas 410 from each other.

[0050] Using a fourth mask as a shield, a second p-doping is performed on the semiconductor substrate. The depth of the second p-doping is controlled, thereby forming a segmentation structure 430. The segmentation structure 430 is used to deepen the photosensitive area 411. The fabrication order of the segmentation structure 420 and the segmentation structure 430 can be adjusted. The segmentation structure 430 can be formed by the first p-doping first, and then the segmentation structure 420 can be formed by the second p-doping.

[0051] Of course, in other embodiments, after N-type doping is formed on the front side, p-doping of the partition structure 420 and partition structure 430 can be implanted, and the implantation of the two p-dops can be carried out in an existing manner.

[0052] like Figure 6b As shown, one of the manufacturing methods includes: Compared to Figure 6a The fabrication method no longer uses a fourth mask to block the second p-doping of the semiconductor substrate. Instead, it directly forms a segmented structure based on the P-type semiconductor substrate. Generally, the semiconductor substrate used to form the semiconductor structure layer is a P-type substrate, such as a P-epi layer. In this example, other areas are doped directly based on the mask pattern, and the segmented structure is automatically formed in the corresponding defined areas.

[0053] like Figure 6c As shown, one of the manufacturing methods includes: Compared to Figure 6a and Figure 6b The fabrication method uses a fifth mask instead of the first mask as a shield, and then uses a second mask to form the photosensitive doped region 410. That is, the photosensitive doped region 410 is formed by using the fifth mask as a shield, and the subsequent segmentation structure is formed in the photosensitive doped region 410.

[0054] Specifically, a semiconductor substrate is provided, and a fifth photomask is used as a shield to perform n-doping on the semiconductor substrate. The depth of n-doping is controlled so that the n-doping simultaneously forms a deep photosensitive region 411 and a shallow photosensitive region 412. The semiconductor substrate is made of materials such as silicon or germanium. In some embodiments, the semiconductor substrate may also include at least one or more other photosensitive materials, such as silicon-germanium, silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, indium, antimony, semiconductor-on-insulator, or combinations thereof.

[0055] Using a third mask as a shield, the semiconductor substrate undergoes a first p-doping process, penetrating the entire substrate to form a separator structure 420. This separator structure 420 separates multiple photosensitive pixel areas 410 from each other. Using a fourth mask as a shield, the semiconductor substrate undergoes a second p-doping process. The depth of the second p-doping is controlled to form a segmentation structure 430, which separates the deeper photosensitive areas 411. The fabrication order of the separator structure 420 and the segmentation structure 430 can be adjusted; for example, the segmentation structure 430 can be formed first using the first p-doping, followed by the second p-doping to form the separator structure 420. Of course, other methods can also be used to form the separator structures. Figure 6c This is just an example.

[0056] like Figure 6d As shown, one of the manufacturing methods includes: Compared to Figure 6a and Figure 6b The main difference in the fabrication method is that a third mask is used as a shield to perform the first p-doping on the semiconductor substrate, forming a partition structure 420. Simultaneously, the region corresponding to the partition structure 430 is also doped to form the partition structure 430. In other words, three masks are used as shields to perform the first p-doping on the semiconductor substrate, simultaneously forming both the partition structure 420 and the partition structure 430. For the fabrication method of the photosensitive doped region 410, please refer to... Figure 6a or Figure 6c .

[0057] like Figure 6e As shown, one of the manufacturing methods includes: Compared to Figure 6a and Figure 6b The main difference in the fabrication method is as follows: A third mask is used as a shield to perform the first p-doping on the semiconductor substrate, forming the partition structure 420. Simultaneously, the region corresponding to the partition structure 430 is also doped to form the partition structure 430. Then, a fourth mask is used as a shield to perform a second p-doping on the semiconductor substrate, controlling the depth of the second p-doping to achieve the second p-doping of the partition structure 430. In other words, three masks are first used as shields to perform the first p-doping on the semiconductor substrate, simultaneously forming the partition structure 420 and the partition structure 430. Then, a fourth mask is used as a shield to perform a second p-doping on the partition structure 430, resulting in different p-doping concentrations for the partition structure 420 and the partition structure 430. For the fabrication method of the photosensitive doped region 410, please refer to [reference needed]. Figure 6a or Figure 6c .

[0058] [Example 2] Figure 7 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 2 of this utility model. Figure 8 This is a schematic diagram of the cross-sectional structure of the image sensor in the deep photosensitive area of ​​Embodiment 2 of this utility model. Figure 7 and Figure 8 As shown, the image sensor provided in Embodiment 2 of this utility model is the same as that in Embodiment 1 ( Figures 3 to 6e The image sensors in these are basically the same, the differences being: In this embodiment, the segmentation structure 430 divides the photosensitive pixel area 410 into N 2 There are 2 subregions, where N is an integer greater than or equal to 2. For example... Figure 8 As shown, the top view of the segmentation structure 430 is a grid-like structure, thereby dividing the photosensitive pixel area 410 into nine sub-regions. Optionally, the segmentation structure 430 divides the photosensitive pixel area 410 into multiple sub-regions of equal area, so that each sub-region can contribute more fully to the FWC. Of course, in other embodiments, the pattern of the segmentation structure 430 can also be set according to the actual situation to divide each photosensitive pixel area 410 into an appropriate number of sub-regions.

[0059] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0060] [Example 3] Figure 9 This is a schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 3 of this utility model. (See diagram below.) Figure 9 As shown, the image sensor provided in Embodiment 3 of this utility model is the same as that in Embodiment 1 ( Figures 3 to 6e Example 2 Figure 8 The image sensors in these are basically the same, the differences being: In this embodiment, the partition structure 430 includes a first doped region 431 and a second doped region 432 stacked on top of each other. In one implementation, one of the first doped region 431 and the second doped region 432 has the same doping concentration as the partition structure 420, while the other has a different doping concentration. That is, the partition structure 430 is formed of two second conductivity type semiconductors with different doping concentrations, one of which has the same p-doping concentration as the partition structure 420. The arrangement of the first doped region 431 and the second doped region 432 is beneficial for controlling signal transmission. Optionally, the first doped region 431 has the same doping concentration as the partition structure 420, while the second doped region 432 has a lower doping concentration than the partition structure 420.

[0061] Figure 10This is a structural flowchart of the image sensor manufacturing method in Embodiment 3 of this utility model. Figure 10 As shown, the method for manufacturing an image sensor includes: After forming photosensitive pixel regions 410 on a semiconductor substrate using n-doping, a third mask is used as a shield to perform the first p-doping on the semiconductor substrate. This first p-doping forms the first doped region 431 of the separation structure 420 and the partition structure 430. The separation structure 420 is used to separate the multiple photosensitive pixel regions 410 from each other. The fabrication method for forming the photosensitive pixel regions 410 can be found in [reference needed]. Figure 6a or Figure 6c Then, a fourth mask is used as a shield to perform a second p-doping on the semiconductor substrate. The depth of the second p-doping is controlled so that the second p-doping forms a second doped region 432, thereby forming a segmented structure 430 together with the first doped region 431 and the second doped region 432.

[0062] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0063] [Example 4] Figure 11 This is one of the schematic diagrams of the longitudinal section structure of the image sensor in Embodiment 4 of this utility model. Figure 12 This is the second schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 4 of this utility model. Figure 13 This is the third schematic diagram of the longitudinal cross-sectional structure of the image sensor in Embodiment 4 of this utility model. (See diagram below.) Figures 11-13 As shown, the image sensor provided in Embodiment 4 of this utility model is the same as that in Embodiment 1 ( Figures 3 to 6e Example 2 Figure 8 Example 3 Figures 9 to 10 The image sensors in these are basically the same, the differences being: In one embodiment, such as Figure 11 As shown, the doping concentrations of the partition structure 420 and the segmentation structure 430 are the same, that is, both the partition structure 420 and the segmentation structure 430 are formed using the same concentration of p doping.

[0064] In another embodiment, such as Figure 12 As shown, a trench isolation structure (DTI) 421 is provided in the partition structure 420. Optionally, the trench isolation structure 421 penetrates the partition structure 420, that is, a trench isolation structure 421 is also provided in the partition structure 420, thereby increasing the isolation effect between adjacent photosensitive pixel areas 410.

[0065] In another embodiment, such as Figure 13As shown, a unit deep trench isolation 433 is provided within the segmentation structure 430. The semiconductor structure layer 400 is located between the circuit connection layer 300 and the optical structure layer 500. The unit deep trench isolation 433 is disposed on the side of the segmentation structure 430 near the optical structure layer 500, and the height of the unit deep trench isolation 433 is less than the height of the segmentation structure 430. By providing unit deep trench isolation 433 within the segmentation structure 430, quantum efficiency (QE) performance, near-infrared (NIR) light sensitivity, and / or crosstalk can be improved. Furthermore, the unit deep trench isolation 433 includes, but is not limited to, a silicon oxide structure, which can be formed based on back-side etching and filling processes. Placing the unit deep trench isolation 433 within the P-doped segmentation structure 430 can further improve high-temperature performance. Optionally, the center of the unit deep trench isolation 433 coincides with the center of the segmentation structure 430. Further, there is a gap between the outer edge of the unit deep trench isolation 433 and the outer edge of the segmentation structure 430. Since the segmentation structure 430 is located on the side of the semiconductor structure layer 400 close to the optical structure layer 500, it is advantageous to set the unit deep trench isolation 433 on the side of the segmentation structure 430 close to the optical structure layer 500; moreover, the same mask can be used to fabricate the unit deep trench isolation 433 and the segmentation structure 430.

[0066] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, and Embodiment 3, and will not be repeated here.

[0067] This application also provides an electronic device including the image sensor described above. The electronic device may be, for example, a digital camera, a camcorder, a portable terminal, a surveillance camera, or a camera used in a medical endoscope.

[0068] In this document, the directional terms such as up, down, left, right, front, and back are defined according to the position of the structures in the accompanying drawings and the relative positions of the structures, and are only used for clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second," etc., used herein are only used for distinction in name and are not used to limit the number or order.

[0069] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present utility model. These are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. An image sensor, characterized in that, The system includes a circuit connection layer (300), an optical structure layer (500), and a semiconductor structure layer (400). The semiconductor structure layer (400) has photosensitive pixel areas (410) arranged in an array and a partition structure (420) that separates the multiple photosensitive pixel areas (410) from each other and penetrates the semiconductor structure layer (400). Each photosensitive pixel area (410) is provided with a partition structure (430) that divides the photosensitive pixel area (410) into at least two sub-regions. The partition structure (430) is located on the side of the semiconductor structure layer (400) away from the circuit connection layer (300), and the height of the partition structure (430) is less than the height of the partition structure (420).

2. The image sensor according to claim 1, characterized in that, Each photosensitive pixel area (410) includes a deep photosensitive area (411) and a shallow photosensitive area (412) stacked on top of each other. The deep photosensitive area (411) is located on the side of the semiconductor structure layer (400) away from the circuit connection layer (300), and the shallow photosensitive area (412) is located on the side of the semiconductor structure layer (400) close to the circuit connection layer (300). The segmentation structure (430) divides the deep photosensitive area (411) into multiple sub-regions, and a charge transport channel region is configured in the shallow photosensitive area (412) based on the segmentation structure (430). The charge transport channel region is located on the side of the semiconductor structure layer (400) close to the circuit connection layer (300).

3. The image sensor according to claim 2, characterized in that, The segmentation structure (430) has a transmission depth with the surface of the semiconductor structure layer (400) near the circuit connection layer (300), and the photosensitive pixel area (410) has a charge transport channel. The transmission depth of the segmentation structure (430) at different positions is the same or has a negative correlation with the distance between the position and the charge transport channel.

4. The image sensor according to claim 2, characterized in that, The height of the segmented structure (430) is equal to the height of the deep photosensitive region (411); and / or, the doping concentration of the deep photosensitive region (411) is the same as or different from the doping concentration of the shallow photosensitive region (412).

5. The image sensor according to claim 1, characterized in that, The photosensitive pixel area (410) is a first type of conductive semiconductor, and the separator structure (420) and the partition structure (430) are second type of conductive semiconductors, which are different from the first type of conductive semiconductor.

6. The image sensor according to claim 5, characterized in that, The doping concentrations of the partition structure (420) and the segmentation structure (430) may be the same or different; and / or, the segmentation structure (430) includes a plurality of sub-segmentation structures along a normal direction perpendicular to the surface of the semiconductor structure layer (400), and the doping concentration of each sub-segmentation structure decreases toward the circuit connection layer (300).

7. The image sensor according to claim 1, characterized in that, The segmentation structure (430) includes a first doped region (431) and a second doped region (432) stacked on top of each other, wherein the doping concentrations of the first doped region (431) and the second doped region (432) are different; or, the segmentation structure (430) includes a first doped region (431) and a second doped region (432) stacked on top of each other, wherein one of the first doped region (431) and the second doped region (432) has the same doping concentration as the segmentation structure (420), and the other has a different doping concentration than the segmentation structure (420).

8. The image sensor according to any one of claims 1-7, characterized in that, The segmentation structure (430) divides the photosensitive pixel area (410) into N 2 There are 2 subregions, where N is an integer greater than or equal to 2.

9. The image sensor according to any one of claims 1-7, characterized in that, The partition structure (420) is provided with a grooved isolation structure (421), which penetrates the partition structure (420).

10. The image sensor according to any one of claims 1-7, characterized in that, The segmentation structure (430) is provided with a unit deep trench isolation (433). The semiconductor structure layer (400) is located between the circuit connection layer (300) and the optical structure layer (500). The unit deep trench isolation (433) is provided on the side of the segmentation structure (430) close to the optical structure layer (500). The height of the unit deep trench isolation (433) is less than the height of the segmentation structure (430).

11. The image sensor according to any one of claims 1-7, characterized in that, The circuit connection layer (300) is provided with a transmission transistor (310), and the transmission transistor (310) corresponds one-to-one with the photosensitive pixel area (410).

12. The image sensor according to claim 11, characterized in that, The photosensitive pixel area (410) corresponds one-to-one with the floating diffusion node working area; or, at least two photosensitive pixel areas (410) correspond to one floating diffusion node working area, wherein when four photosensitive pixel areas (410) correspond to one floating diffusion node working area, the charge transport path of each photosensitive pixel area (410) is symmetrical with respect to the center of the floating diffusion node working area.

13. An electronic device, characterized in that, Including the image sensor as described in any one of claims 1-12.

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