Solid-state imaging device, electronic device and mobile object

Abstract

A solid-state imaging device according to one embodiment of the present disclosure comprises a semiconductor layer, a first capacitance part, and a second capacitance part. The semiconductor layer is laminated on a first Si substrate and includes a photoelectric conversion region and a floating diffusion region. The photoelectric conversion region has prescribed wavelength selectivity. The floating diffusion region converts an electric charge, which has successfully been transferred from the photoelectric conversion region, to an electric signal and outputs the signal. The first capacitance part is formed on the first Si substrate and retains a reset voltage of the floating diffusion region when the voltage of the floating diffusion region has been reset. The second capacitance part is formed on the first Si substrate and retains a signal voltage generated by the electric signal.

Description

[Technical Field]

[0001] The present disclosure relates to a solid-state imaging device, an electronic device, and a mobile object. [Background technology]

[0002] Various solid-state imaging devices have been proposed so far (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-157816 [Patent Document 2] Japanese Patent Application Publication No. 2018-107724 Summary of the Invention

[0004] In the above-mentioned solid-state imaging device, from the viewpoint of improving image quality, it is desirable to improve the signal-to-noise ratio (SNR) and to apply a global shutter system. Therefore, it is desirable to provide a solid-state imaging device that can adopt the global shutter system while achieving a high SNR, as well as electronic equipment and mobile objects equipped with the same.

[0005] A solid-state imaging device according to an embodiment of the present disclosure includes a semiconductor layer, a first capacitance section, and a second capacitance section. The semiconductor layer is stacked on a Si substrate and includes a photoelectric conversion region and a floating diffusion region. The photoelectric conversion region has a predetermined wavelength selectivity. The floating diffusion region converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal. The first capacitance section is formed on the Si substrate and holds a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset. The second capacitance section is formed on the Si substrate and holds a signal voltage generated by the electrical signal.

[0006] An electronic device according to an embodiment of the present disclosure includes the above-described solid-state imaging device.

[0007] A moving object according to an embodiment of the present disclosure includes the above-described solid-state imaging device.

[0008] In a solid-state imaging device, an electronic device, and a mobile object according to an embodiment of the present disclosure, two capacitance units (a first capacitance unit and a second capacitance unit) are formed on a Si substrate. This allows noise contained in the signal voltage to be removed, for example, by calculating the difference between the reset voltage held in the first capacitance unit and the signal voltage held in the second capacitance unit. As a result, the generation of kTC noise can be suppressed. Furthermore, in the present disclosure, a floating diffusion region is provided in the semiconductor layer separately from a photoelectric conversion region, and charges generated in the photoelectric conversion region are transferred to the floating diffusion region. Here, noise can be removed by the two capacitance units provided downstream of the floating diffusion region, allowing the capacitance of the floating diffusion region to be reduced. This increases conversion efficiency and improves SN ratio. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a solid-state imaging device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of a circuit configuration of a sensor pixel. [Figure 3] FIG. 2 is a diagram illustrating an example of a cross-sectional configuration of a sensor pixel. [Figure 4] FIG. 10 is a diagram illustrating a modified example of the circuit configuration of the S / H unit. [Figure 5] FIG. 10 is a diagram illustrating a modified example of the circuit configuration of the sensor pixel. [Figure 6] FIG. 10 is a diagram illustrating a modified example of the circuit configuration of the amplifier unit. [Figure 7] FIG. 10 is a diagram illustrating a modified example of the cross-sectional configuration of the sensor pixel. [Figure 8] FIG. 10 is a diagram illustrating a modified example of the cross-sectional configuration of the sensor pixel. [Figure 9] FIG. 10 is a diagram illustrating a modified example of the cross-sectional configuration of the sensor pixel. [Figure 10] FIG. 10 is a diagram illustrating a modified example of the cross-sectional configuration of the sensor pixel. [Figure 11] FIG. 1 is a diagram illustrating an example of a schematic configuration of an imaging system including a solid-state imaging device according to the above embodiment and its modified example. [Figure 12] 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; [Figure 13] FIG. 2 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit. [Figure 14] FIG. 1 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. [Figure 15] FIG. 2 is a block diagram showing an example of the functional configuration of a camera head and a CCU. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] Furthermore, in this specification and drawings, multiple components having substantially the same or similar functional configurations may be distinguished by adding different numbers after the same reference numeral. However, if there is no need to particularly distinguish between multiple components having substantially the same or similar functional configurations, only the same reference numeral will be used. Furthermore, similar components in different embodiments may be distinguished by adding different letters after the same reference numeral. However, if there is no need to particularly distinguish between similar components, only the same reference numeral will be used.

[0012] In addition, the drawings referred to in the following description are intended to facilitate the description and understanding of one embodiment of the present disclosure, and for clarity, the shapes, dimensions, ratios, etc. shown in the drawings may differ from the actual shapes, dimensions, ratios, etc. Furthermore, the solid-state imaging element shown in the drawings may be appropriately modified in design in consideration of the following description and known technologies. In addition, in the description using a cross-sectional view of the solid-state imaging element, the vertical direction of the stacked structure of the solid-state imaging element corresponds to the relative direction when the incident surface on which light is incident on the solid-state imaging element is set as the top, and may differ from the vertical direction according to the actual gravitational acceleration.

[0013] Furthermore, in the following description, expressions relating to size and shape do not only mean values ​​identical to mathematically defined numerical values ​​or geometrically defined shapes, but also include cases where there are industrially acceptable differences in the manufacturing process of solid-state imaging devices, or shapes similar to those shapes.

[0014] Furthermore, in the following description of the circuit configuration, unless otherwise specified, "connection" means electrical connection between multiple elements. In addition, in the following description, "connection" includes not only direct and electrical connection between multiple elements, but also indirect and electrical connection via other elements.

[0015] The explanation will be given in the following order. 1. Embodiment (Solid-State Imaging Device) 2. Modification (Solid-state imaging device) 3. Application example (imaging system) 4. Application Examples Mobile application example Application example to endoscopic surgery system

[0016] <1. Embodiment> [composition] A solid-state imaging device 1 according to an embodiment of the present disclosure will be described. The solid-state imaging device 1 is, for example, a global shutter type image sensor formed of a CMOS (Complementary Metal Oxide Semiconductor) image sensor or the like. The solid-state imaging device 1 captures an image by receiving light from a subject, photoelectrically converting the light, and generating an image signal. The solid-state imaging device 1 outputs a pixel signal corresponding to the incident light.

[0017] The global shutter method is a method of performing global exposure in which exposure is basically started and ended simultaneously for all pixels. Here, "all pixels" refers to all pixels that appear in an image, excluding dummy pixels and the like. Furthermore, the global shutter method also includes a method of performing global exposure in units of multiple rows (e.g., several tens of rows) rather than simultaneously for all pixels, while moving the area where global exposure is performed, as long as the time difference and image distortion are small enough to not be a problem. Furthermore, the global shutter method also includes a method of performing global exposure on pixels in a predetermined area, rather than on all pixels that appear in an image. Note that the present disclosure is not limited to application to CMOS image sensors.

[0018] 1 shows an example of a schematic configuration of a solid-state imaging device 1. The solid-state imaging device 1 includes a pixel array section 10 in which a plurality of sensor pixels 11 that perform photoelectric conversion are arranged in a matrix. The sensor pixels 11 correspond to a specific example of a "pixel" in the present disclosure. The solid-state imaging device 1 further includes a peripheral circuit 20 that is arranged in a peripheral region of the pixel array section 10. The peripheral circuit 20 includes a vertical drive circuit 21, a column signal processing circuit 22, a horizontal drive circuit 23, an output circuit 24, and a system control circuit 25.

[0019] The pixel array unit 10 has a plurality of sensor pixels 11 arranged two-dimensionally in a matrix, for example. The pixel array unit 10 has a plurality of pixel rows each consisting of a plurality of sensor pixels 11 arranged in a horizontal direction (the horizontal direction on the paper) and a plurality of pixel columns each consisting of a plurality of sensor pixels 11 arranged in a vertical direction (the vertical direction on the paper). The pixel array unit 10 has a plurality of pixel drive lines for each pixel row and one vertical signal line VSL for each pixel column. The pixel drive lines transmit control signals for reading signals from each sensor pixel 11. Ends of the plurality of pixel drive lines are connected to a plurality of output terminals of a vertical drive circuit 21 corresponding to each pixel row.

[0020] The vertical drive circuit 21 is configured with a shift register, an address decoder, etc., and is a pixel drive unit that drives, for example, each pixel row of the sensor pixels 11. The pixel signals output from each sensor pixel 11 in the pixel row selected and scanned by the vertical drive circuit 21 are supplied to the column signal processing circuit 22 through each vertical signal line VSL.

[0021] The column signal processing circuits 22 are arranged for each column of the pixel array unit 10, and perform signal processing such as noise removal for each pixel column on pixel signals output from the sensor pixels 11 of a predetermined unit pixel row. The column signal processing circuits 22 perform, for example, correlated double sampling (CDS) processing to remove fixed pattern noise specific to each pixel. The column signal processing circuits 22 include, for example, a single-slope A / D converter. The single-slope A / D converter includes, for example, a comparator and a counter circuit, and performs AD (Analog-Digital) conversion on the pixel signals.

[0022] The horizontal drive circuit 23 is configured by, for example, a shift register. The horizontal drive circuit 23 sequentially outputs horizontal scanning pulses to select each of the above-mentioned column signal processing circuits 22 in turn, and causes each column signal processing circuit 22 to output a pixel signal to a horizontal signal line.

[0023] The output circuit 24 performs signal processing on pixel signals sequentially supplied from each of the column signal processing circuits 22 via horizontal signal lines, and outputs the resulting signals. The output circuit 24 may function as a functional unit that performs buffering, for example, and may perform processes such as black level adjustment, column variation correction, and various digital signal processing. Buffering refers to temporarily storing pixel signals to compensate for differences in processing speed and transfer speed when exchanging pixel signals.

[0024] The system control circuit 25 receives externally applied clocks, data instructing the operation mode, and the like, and outputs data such as internal information of the sensor pixels 11. The system control circuit 25 also has a timing generator that generates various timing signals. The system control circuit 25 controls the driving of peripheral circuits such as the vertical drive circuit 21, the column signal processing circuit 22, and the horizontal drive circuit 23 based on the various timing signals generated by the timing generator.

[0025] Fig. 2 shows an example of a circuit configuration of the sensor pixel 11. As shown in Fig. 2, the sensor pixel 11 includes, for example, a photoelectric conversion unit 11a, an amplifier unit 11b, an S / H (Sample and Hold) unit 11c, and a readout unit 11d.

[0026] The photoelectric conversion unit 11a includes, for example, a drain transistor OFG, a charge storage transistor ASE, a transfer transistor TRG, a photoelectric conversion element PD, and a floating diffusion FD. The drain transistor OFG, the charge storage transistor ASE, and the transfer transistor TRG are configured, for example, by N-type MOS transistors. Pixel drive lines are connected to the gates of the drain transistor OFG, the charge storage transistor ASE, and the transfer transistor TRG, respectively.

[0027] The drain of the discharge transistor OFG is connected to the power supply line VDR, and the source is connected to the photoelectric conversion element PD via the charge storage transistor ASE. The discharge transistor OFG initializes (resets) the photoelectric conversion element PD in response to a reset signal applied to the gate electrode. For example, when the discharge transistor OFG, the charge storage transistor ASE, and the transfer transistor TRG are turned on, the potential of the photoelectric conversion element PD is reset to the level of the power supply voltage VDD. In other words, the photoelectric conversion element PD is initialized.

[0028] The charge-storage transistor ASE controls the potential of the photoelectric conversion element PD in response to a drive signal applied to its gate electrode. For example, when the charge-storage transistor ASE is turned on, the potential of the photoelectric conversion element PD deepens, and when the charge-storage transistor ASE is turned off, the potential of the photoelectric conversion element PD shallows. The transfer transistor TRG is connected between the charge-storage transistor ASE and the floating diffusion FD, and transfers the charge held in the photoelectric conversion element PD to the floating diffusion FD in response to a drive signal applied to its gate electrode. For example, when the charge-storage transistor ASE and the transfer transistor TRG are turned on, the charge stored in the photoelectric conversion element PD is transferred to the floating diffusion FD via the charge-storage transistor ASE and the transfer transistor TRG.

[0029] The floating diffusion FD is a floating diffusion region that converts the charges transferred from the photoelectric conversion element PD via the transfer transistor TRG into an electrical signal (for example, a voltage signal) and outputs the electrical signal. The floating diffusion FD is connected to the amplifier 11b at the subsequent stage.

[0030] The amplifier unit 11b has, for example, an amplifier transistor AMP1 and a select transistor SEL1. The amplifier transistor AMP1 and the select transistor SEL1 are configured, for example, by N-type MOS transistors. A floating diffusion FD is connected to the gate of the amplifier transistor AMP1. The drain of the amplifier transistor AMP1 is connected to a power supply line VDD, and the source is connected to the drain of the select transistor SEL1. The gate of the select transistor SEL1 is connected to a row select line. The drain of the select transistor SEL1 is connected to the source of the amplifier transistor AMP1, and the source is connected to a constant voltage line. The amplifier unit 11b is, for example, a source follower circuit that reads out the voltage of the floating diffusion FD.

[0031] The S / H unit 11c includes a capacitance element C1 for holding a P-phase voltage that is a reference for the signal, and a capacitance element C2 for holding a D-phase voltage that is an output after photoelectric conversion. The capacitance elements C1 and C2 are, for example, MIM (metal-insulator-metal l ) type, MOS capacitor, or trench capacitor. A MOS capacitor is a capacitive element that uses the capacitance of a gate oxide film between the gate and the Si substrate. A trench capacitor is an element in which the gate is buried in the Si substrate and the capacitance can be increased by increasing the area of ​​the oxide film. The S / H unit 11c further includes a sampling transistor SAM and a clipping transistor CLP. The sampling transistor SAM and the clipping transistor CLP are, for example, configured by N-type MOS transistors.

[0032] A row selection line is connected to the gate of the sampling transistor SAM. The drain of the sampling transistor SAM is connected to the connection point between the amplification transistor AMP1 and the selection transistor SEL1, and the source is connected to the connection point a1 between the capacitance elements C1 and C2. The sampling transistor SAM is inserted in series in a signal path P1 from the floating diffusion FD to the readout unit 11d. One ends of the capacitance elements C1 and C2 are connected to the source of the sampling transistor SAM. The other end of the capacitance element C1 is connected to the ground line GND. The other end of the capacitance element C2 is connected to the readout unit 11d. The capacitance element C1 is connected to a branch of the signal path P1. The capacitance element C2 is inserted in series in the signal path P1. A row selection line is connected to the gate of the clip transistor CLP. The drain of the clip transistor CLP is connected to the power supply line VRR, and the source is connected to the terminal of the capacitance element C2 on the readout unit 11d side.

[0033] The S / H unit 11c holds the voltage (reset voltage) of the floating diffusion FD when the voltage of the floating diffusion FD is reset in the capacitance element C1. The S / H unit 11c further holds the signal voltage generated by the electrical signal (e.g., a voltage signal) output from the floating diffusion FD in the capacitance element C2.

[0034] The readout unit 11d reads out a reset voltage from the capacitive element C1 and a signal voltage from the capacitive element C2. The readout unit 11d amplifies the signal output from the S / H unit 11c and outputs it to the vertical signal line VSL. The readout unit 11d includes, for example, an amplification transistor AMP2 and a selection transistor SEL2. The gate of the amplification transistor AMP2 is connected to the capacitive element C2 via a signal path P1. The drain of the amplification transistor AMP2 is connected to a power supply line VDD, and the source is connected to the drain of the selection transistor SEL2. The gate of the selection transistor SEL2 is connected to a row selection line. The drain of the selection transistor SEL2 is connected to the source of the amplification transistor AMP2, and the drain is connected to the vertical signal line VSL. The readout unit 11d is, for example, a source follower circuit that reads out the voltage of the terminal of the capacitive element C2 on the readout unit 11d side.

[0035] 3 shows an example of a cross-sectional configuration of the sensor pixel 11. The sensor pixel 11 is configured, for example, by bonding two substrates (a light-receiving substrate 30 and a signal processing substrate 40) together. The two substrates (the light-receiving substrate 30 and the signal processing substrate 40) are bonded together by, for example, joining the pad electrode 36 on the light-receiving substrate 30 side and the pad electrode 42a on the signal processing substrate 40 side to each other.

[0036] The sensor pixel 11 further includes a color filter layer 51, a black matrix 52, a protective layer 53, and a lens 54, for example, on the light incident surface S1 side of the light receiving substrate 30. The color filter layer 51 is disposed opposite the photodiode PD and is in contact with the light incident surface S1 of the light receiving substrate 30, for example. The color filter layer 51 is disposed for each sensor pixel 11, for example. The black matrix 52 is disposed in the same layer as the color filter layer 51 and is in contact with the light incident surface S1 of the light receiving substrate 30, for example. The black matrix 52 is disposed at the boundary of the sensor pixel 11 and covers the side surface of the color filter layer 51. The protective layer 53 is formed in contact with the surfaces of the color filter layer 51 and the black matrix 52 and protects the color filter layer 51 and the black matrix 52. The protective layer 53 is made of, for example, a well-known insulating material (e.g., SiO2 or SiN). The lens 54 is disposed opposite the photodiode PD and is in contact with the protective layer 53, for example. The lens 54 is arranged for each sensor pixel 11, for example.

[0037] The light-receiving substrate 30 is stacked on the signal processing substrate 40. The light-receiving substrate 30 has, for example, a semiconductor layer 31. The semiconductor layer 31 includes a photodiode PD, which is a photoelectric conversion region, and a floating diffusion FD. A discharge transistor OFG, a charge storage transistor ASE, and a transfer transistor TRG are formed on the surface of the semiconductor layer 31 facing the signal processing substrate 40. An insulating layer 34 is formed in contact with the surface of the semiconductor layer 31 facing the signal processing substrate 40. Parts of the insulating layer 34 form gate insulating films for the discharge transistor OFG, the charge storage transistor ASE, and the transfer transistor TRG.

[0038] A plurality of openings are provided in the insulating layer 34. The floating diffusion FD is electrically connected to the gate of the amplification transistor AMP1 via wiring in the insulating layers 35 and 42b, which will be described later. The drain of the discharge transistor OFG is electrically connected to the power supply line VDR via wiring in the insulating layers 35 and 42b, which will be described later. The gates of the charge storage transistor ASE, the transfer transistor TRG, and the discharge transistor OFG are connected to a plurality of pixel drive lines via wiring in the insulating layers 35 and 42b, which will be described later. The plurality of pixel drive lines are provided, for example, in the insulating layer 42b.

[0039] An insulating layer 35 is formed in contact with the surface of the insulating layer 34 facing the signal processing substrate 40. The insulating layer 35 is a layer that protects the transfer transistor TRG and the like formed in the semiconductor layer 31. A plurality of pad electrodes 36 are formed on the surface of the insulating layer 35 facing the signal processing substrate 40. A connection portion 37 that electrically connects the floating diffusion FD and the pad electrode 36 to each other is formed in the insulating layer 35. A connection portion 37 that electrically connects the drain of the emission transistor OFG to a pad electrode 36 different from the pad electrode 36 electrically connected to the floating diffusion FD is further formed in the insulating layer 35. The connection portion 37 is, for example, a vertical wiring that penetrates the insulating layer 35 in the thickness direction.

[0040] A dark current suppression layer 32 and a transparent electrode layer 33 are laminated in this order from the light incident surface S1 side on the surface of the semiconductor layer 31 on the light incident surface S1 side. The dark current suppression layer 32 suppresses dark current generated in the semiconductor layer 31. The transparent electrode layer 33 is an electrode on the light incident surface S1 side of the photodiode PD. The transparent electrode layer 33 is provided in a position facing the light incident surface S1.

[0041] The semiconductor layer 31 is a layer made of a material different from the Si substrate (described later) included in the signal processing substrate 40. The semiconductor layer 31 (photodiode PD) is, for example, an InGaAs layer, an organic photoelectric conversion layer, a Ge layer, a SiGe layer, an amorphous silicon layer, or a quantum dot layer. The insulating layer 345 is, for example, made of a well-known insulating material (for example, SiO2 or SiN). When the semiconductor layer 31 is an InGaAs layer, the dark current suppression layer 32 is, for example, an InP layer. The transparent electrode layer 33 is, for example, made of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide).

[0042] The signal processing substrate 40 has, for example, a semiconductor substrate 41. The semiconductor substrate 41 is, for example, a Si substrate. On the semiconductor substrate 41, for example, an amplifier section 11b, an S / H section 11c (capacitance elements C1, C2), and a readout section 11d are formed. A wiring layer 42 is laminated on the surface of the semiconductor substrate 41 on the light-receiving substrate 30 side. The wiring layer 42 is composed of, for example, a plurality of pad electrodes 42a, a plurality of wires that electrically connect the plurality of pad electrodes 42a and the capacitance elements C1, C2, etc. to each other, and an insulating layer 42b that insulates and separates them. A plurality of pad electrodes 36 The pad electrodes 42a are bonded to each other by being joined together.

[0043] [Operation] Next, the operation of the solid-state imaging device 1 will be described. First, the solid-state imaging device 1 turns on and off the drain transistor OFG, the charge-storage transistor ASE, and the transfer transistor TRG. This starts the accumulation of signal charges generated by photoelectric conversion in the photodiode PD in the semiconductor layer 31. Next, the solid-state imaging device 1 turns on the selection transistor SEL1, then turns on the sampling transistor SAM, and turns on and off the clipping transistor CLP. This resets the voltage of the floating diffusion FD, the voltage V1 at the connection point a1 between the capacitance elements C1 and C2, and the voltage V2 at the connection point a2 between the capacitance element C2 and the clipping transistor CLP to predetermined values. A potential difference corresponding to the voltage V1 at the connection point a1 at this time is applied to the capacitance element C1.

[0044] Next, the solid-state imaging device 1 turns on and off the transfer transistor TRG. As a result, the signal charge accumulated in the semiconductor layer 31 (photodiode PD) is transferred from the semiconductor layer 31 (photodiode PD) to the floating diffusion FD. After that, the voltage of the floating diffusion FD is amplified by the amplifier transistor AMP1 and applied to the connection point a1 via the sampling transistor SAM. Fluctuations in the voltage V1 at the connection point a1 are propagated to the connection point a2 by capacitive coupling, causing the voltage V2 at the connection point a2 to fluctuate. After that, the solid-state imaging device 1 turns off the sampling transistor SAM and the selection transistor SEL1.

[0045] Next, the solid-state imaging device 1 performs rolling readout for each pixel row. Specifically, the solid-state imaging device 1 first turns on the selection transistor SEL2 for each pixel row. Then, the voltage V2 (signal voltage) at the connection point a2 is input to the column signal processing circuit 22 via the vertical signal line VSL for each pixel row. The column signal processing circuit 22 performs A / D conversion on the input signal voltage. After turning on the selection transistor SEL2 for each pixel row, the solid-state imaging device 1 turns on and off the clipping transistor CLP. As a result, the voltage V2 at the connection point a2 becomes a voltage value corresponding to the potential difference accumulated in the capacitive element C1. At this time, the voltage V2 (reset voltage) at the connection point a2 is input to the column signal processing circuit 22 via the vertical signal line VSL for each pixel row. The column signal processing circuit 22 performs A / D conversion on the input reset voltage. The column signal processing circuit 22 outputs a voltage corresponding to the difference between the signal voltage and the reset voltage to the output circuit 24 as a pixel signal. In this way, driving by the global shutter method can be performed.

[0046] [effect] Next, the effects of the solid-state imaging device 1 will be described.

[0047] In recent years, as pixel size in CCD and CMOS image sensors has decreased, the amount of light incident on each pixel has decreased, resulting in a decrease in sensitivity and a drop in the S / N ratio. In particular, reducing kTC noise that occurs during reset operations has become a challenge in improving image quality. Furthermore, adopting a global shutter system is also important in improving image quality. Therefore, there is a demand for a solid-state imaging device that can adopt the global shutter system while reducing kTC noise.

[0048] On the other hand, in this embodiment, two capacitance elements C1 and C2 are formed on the semiconductor substrate 41 (Si substrate). This allows, for example, noise contained in the signal voltage to be removed by calculating the difference between the reset voltage held in the capacitance element C1 and the signal voltage held in the capacitance element C2. As a result, the generation of kTC noise can be suppressed. Furthermore, in this embodiment, the floating diffusion FD is provided separately from the photodiode PD in the semiconductor layer 31, and charge generated in the floating diffusion FD is transferred to the photodiode PD. Here, since noise can be removed by the two capacitance elements C1 and C2 provided downstream of the floating diffusion FD, the capacitance of the floating diffusion FD can be reduced. This increases the conversion efficiency and improves the SNR.

[0049] Furthermore, in this embodiment, the capacitive element C2 is inserted in series into the signal path P1 from the floating diffusion FD to the readout section 11d, and the capacitive element C1 is connected to a branch of the signal path P1. This allows the capacitive element C1 to hold the reset voltage, and the capacitive element C2 to hold the signal voltage. As a result, for example, by performing a rolling readout for each pixel row, noise contained in the signal voltage can be removed using the signal voltage read out from the capacitive element C2 and the reset voltage read out from the capacitive element C1. Therefore, the occurrence of kTC noise can be suppressed.

[0050] In this embodiment, an amplifier unit 11b is provided in the signal path P1 between the floating diffusion FD and the capacitive element C1, which allows the potential fluctuation in the floating diffusion FD to be output to the source of the amplifier transistor AMP1 with little loss.

[0051] In this embodiment, the pad electrode 36and the pad electrodes 42a are connected by being bonded to each other. This makes it possible to shorten the signal path electrically connecting the light-receiving substrate 30 and the signal-processing substrate 40 compared to when they are connected via bumps, for example. As a result, it is possible to reduce noise entering the signal path from the outside, for example.

[0052] <2. Modifications> Modifications of the solid-state imaging device 1 according to the above embodiment will be described below.

[0053] [Variation A] FIG. 4 shows a modified example of the circuit configuration of the S / H unit 11c. In the above embodiment, the two capacitive elements C1 and C2 provided in the S / H unit 11c may both be branched and connected to the signal path P1, for example, as shown in FIG. 4. Even in this case, the capacitive element C1 can be made to hold the reset voltage, and the capacitive element C2 can be made to hold the signal voltage. As a result, for example, by performing a rolling readout for each pixel row, noise contained in the signal voltage can be removed using the signal voltage read out from the capacitive element C2 and the reset voltage read out from the capacitive element C1. Therefore, the occurrence of kTC noise can be suppressed.

[0054] In this modification, an amplifier unit 11b is provided in the signal path P1 between the floating diffusion FD and the capacitive element C1, which allows the potential fluctuation in the floating diffusion FD to be output to the source of the amplifier transistor AMP1 with little loss.

[0055] [Variation B] FIG. 5 illustrates a modified circuit configuration of the sensor pixel 11. In the above-described embodiment, for example, as shown in FIG. 5, the sensor pixel 11 may be provided with two S / H units 11c and two readout units 11d. In this case, one S / H unit 11c is provided with a capacitive element C1, and the other S / H unit 11c is provided with a capacitive element C2. The capacitive element C1 branches off and is connected to a signal path P2 from the floating diffusion FD to one S / H unit 11c. The capacitive element C2 branches off and is connected to a signal path P3 from the floating diffusion FD to the other S / H unit 11c. Even in this case, the capacitive element C1 can be made to hold a reset voltage, and the capacitive element C2 can be made to hold a signal voltage. As a result, for example, by performing a rolling readout for each pixel row and using the signal voltage read out from the capacitive element C2 and the reset voltage read out from the capacitive element C1, noise contained in the signal voltage can be removed. This makes it possible to suppress kTC noise.

[0056] In this modification, the signal path P2 between the floating diffusion FD and the capacitive element C1 and the signal path P3 between the floating diffusion FD and the capacitive element C2 share a common path. The amplifier 11b is inserted into this common path. This allows the circuit size of the sensor pixel 11 to be smaller than when one amplifier 11b is provided for each of the capacitive elements C1 and C2. Furthermore, reducing the circuit size of the sensor pixel 11 can reduce, for example, external noise entering the signal path.

[0057] [Variation C] 6 shows a modified circuit configuration of the amplifier unit 11b. In the above-described embodiment and its modifications, the amplifier unit 11b may be configured as a common-source circuit, as shown in FIG. 6. Even in this case, the potential fluctuation in the floating diffusion FD can be output to the source of the amplifier transistor AMP1 with little loss.

[0058] [Variation D] 7 shows a modified example of the cross-sectional configuration of the sensor pixel 11. In the above-described embodiment and its modified examples, for example, as shown in FIG. 7, a high-concentration impurity region 31A doped with a high concentration of impurities may be provided in the semiconductor layer 31. The high-concentration impurity region 31A is formed, for example, in the surface of the semiconductor layer 31 where the floating diffusion FD is exposed. The high-concentration impurity region 31A is further formed, for example, in the surface of the semiconductor layer 31 where the drain of the emission transistor OFG is exposed. By providing the high-concentration impurity region 31A in the semiconductor layer 31 in this way, it is possible to improve the ohmic contact between the semiconductor layer 31 (for example, the floating diffusion FD, the drain of the emission transistor OFG) and the connection portion 37.

[0059] [Variation E] Fig. 8 shows a modified example of the cross-sectional configuration of the sensor pixel 11. In the above-described embodiment and the modified example, for example, as shown in Fig. 8, the semiconductor layer 31 may be composed of a semiconductor layer 31a in which the photodiode PD is formed and a semiconductor layer 31b provided between the semiconductor layer 31a and the insulating layer 34.

[0060] The semiconductor layer 31a is, for example, a layer made of a material different from the Si substrate (described later) included in the signal processing substrate 40. The semiconductor layer 31a is, for example, an InGaAs layer, an organic photoelectric conversion layer, a Ge layer, a SiGe layer, an amorphous silicon layer, or a quantum dot layer. The semiconductor layer 31b is a layer that transfers the signal charge accumulated in the semiconductor layer 31a to the floating diffusion FD. The semiconductor layer 31b is also a layer that discharges the signal charge remaining in the semiconductor layer 31a to the drain of the discharge transistor OFG. The semiconductor layer 31b is, for example, made of a light-transmitting semiconductor material.

[0061] In this way, by providing the semiconductor layer 31b, the signal charges can be transferred and discharged efficiently, which makes it difficult for the signal charges to remain in the semiconductor layer 31b, thereby suppressing the generation of noise caused by the signal charges remaining in the semiconductor layer 31b.

[0062] [Variation F] Fig. 9 shows a modified example of the cross-sectional configuration of the sensor pixel 11. In the above-described embodiment and the modified example, for example, as shown in Fig. 9, the sensor pixel 11 may further include a peripheral circuit board 60.

[0063] The peripheral circuit board 60 has, for example, a semiconductor substrate 61. The semiconductor substrate 61 is, for example, a Si substrate. The semiconductor substrate 61 has, for example, a readout unit 11d formed thereon. The amplifier unit 11b and the S / H unit 11c (capacitance elements C1 and C2) are formed on the semiconductor substrate 61. A wiring layer 62 is laminated on the surface of the semiconductor substrate 61 facing the signal processing board 40. The wiring layer 62 is composed of, for example, a plurality of pad electrodes 62a, a plurality of wires that electrically connect the plurality of pad electrodes 62a to the readout unit 11d, etc., and an insulating layer 62b that insulates and separates them.

[0064] In this modification, a wiring layer 43 is laminated on the surface of the signal processing board 40 facing the peripheral circuit board 60. The wiring layer 43 is composed of, for example, a plurality of pad electrodes 43a, a plurality of wires electrically connecting the plurality of pad electrodes 43a to the S / H section 11c (capacitor elements C1, C2) and the like, and an insulating layer 43b insulating and isolating them. The plurality of pad electrodes 62a and the plurality of pad electrodes 43a are bonded to each other and thereby attached to each other.

[0065] In this way, by providing the peripheral circuit board 60, greater flexibility can be provided in the circuit layout of the circuits (e.g., the amplifier section 11b and the S / H section 11c (capacitive elements C1, C2)) formed on the semiconductor substrate 41 of the signal processing board 40.

[0066] [Variation G] FIG. 10 shows a modified cross-sectional configuration of the sensor pixel 11. In the above-described embodiment and its modifications, for example, as shown in FIG. 10, a wiring layer 38 may be further provided in contact with the surface of the light-receiving substrate 30 facing the signal processing substrate 40. In this case, the wiring layer 38 is composed of, for example, a plurality of pad electrodes 38a, a plurality of pixel drive lines 38b, and an insulating layer 38c that insulates and separates them. The plurality of pad electrodes 38a and the plurality of pad electrodes 42a are joined by being attached to each other. The plurality of pixel drive lines 38b are connected to the gates of the discharge transistor OFG, the charge storage transistor ASE, and the transfer transistor TRG. The plurality of pixel drive lines 38b are also connected to the vertical drive circuit 21.

[0067] In this way, by providing the wiring layer 38, it is not necessary to provide multiple pixel driving lines 38b in the wiring layer 42 of the signal processing substrate 40. This makes it possible to reduce the number of pad electrodes that join the light receiving substrate 30 and the signal processing substrate 40 compared to when the wiring layer 38 is not provided. As a result, it is possible to reduce the size of the sensor pixels 11.

[0068] <3. Application Examples> The solid-state imaging device 1 according to the above-described embodiment and its modified examples can be applied to imaging devices such as digital still cameras and video cameras, portable terminal devices with imaging functions, copiers using solid-state imaging elements in image reading units, and other electronic devices that use solid-state imaging elements in image capture units. Furthermore, the embodiments of the present disclosure can also be applied to robots, drones, automobiles, medical equipment (endoscopes), and the like that include the solid-state imaging device 1. The solid-state imaging device 1 according to the above-described embodiment and its modified examples can be formed as a single chip, or can be formed as a module with imaging functions in which an imaging unit and a signal processing unit or an optical system are packaged together. An example of an imaging system including the solid-state imaging device 1 according to the above-described embodiment and its modified examples will be described below with reference to FIG. 11. FIG. 11 is an explanatory diagram showing an example of an imaging system 2 including the solid-state imaging device 1 according to the above-described embodiment and its modified examples.

[0069] 11 , the imaging system 2 includes, for example, the solid-state imaging device 1 according to the above-described embodiment and its modification, an optical system 141, a shutter device 142, a control circuit 143, a DSP circuit 144, a frame memory 145, a display unit 146, a storage unit 147, an operation unit 148, and a power supply unit 149. In the imaging system 2, the solid-state imaging device 1 according to the above-described embodiment and its modification, the DSP circuit 144, the frame memory 145, the display unit 146, the storage unit 147, the operation unit 148, and the power supply unit 149 are connected to each other via a bus line 150.

[0070] The optical system 141 includes one or more lenses and guides light from a subject (incident light) to the solid-state imaging device 1, forming an image on the light-receiving surface of the solid-state imaging device 1. The shutter device 142 is disposed between the optical system 141 and the solid-state imaging device 1 and controls the light irradiation period and light-blocking period of the solid-state imaging device 1 under the control of the control circuit 143. The solid-state imaging device 1 accumulates signal charges for a certain period in accordance with the light that is imaged on the light-receiving surface via the optical system 141 and the shutter device 142. The signal charges accumulated in the solid-state imaging device 1 are transferred as pixel signals (image data) to the DSP circuit 144 in accordance with a drive signal (timing signal) supplied from the control circuit 143. In other words, the solid-state imaging device 1 receives image light (incident light) incident via the optical system 141 and the shutter device 142 and outputs pixel signals corresponding to the received image light (incident light) to the DSP circuit 144. The control circuit 143 outputs a drive signal that controls the transfer operation of the solid-state imaging device 1 and the shutter operation of the shutter device 142 to drive the solid-state imaging device 1 and the shutter device 142 .

[0071] The DSP circuit 144 is a signal processing circuit that processes pixel signals (image data) output from the solid-state imaging device 1. The frame memory 145 temporarily stores the image data processed by the DSP circuit 144 on a frame-by-frame basis. The display unit 146 is formed of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and displays moving or still images captured by the solid-state imaging device 1. The storage unit 147 records image data of moving or still images captured by the solid-state imaging device 1 in a recording medium such as a semiconductor memory or a hard disk. The operation unit 148 issues operation commands for various functions of the imaging system 2 in accordance with user operations. The power supply unit 149 appropriately supplies various power sources to the solid-state imaging device 1, the DSP circuit 144, the frame memory 145, the display unit 146, the storage unit 147, and the operation unit 148 as operating power sources.

[0072] In this application example, the solid-state imaging device 1 according to the above-described embodiment and its modification example is applied to an imaging system 2. This allows the solid-state imaging device 1 to be made smaller or have higher definition, and therefore a small or high-definition imaging system 2 can be provided.

[0073] <4. Application Examples> [Application example 1] The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0074] FIG. 12 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0075] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 12, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0076] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a braking force of the vehicle, etc.

[0077] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches may be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0078] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc., based on the received images.

[0079] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0080] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0081] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drivetrain control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including avoiding or mitigating collisions between vehicles, following based on the distance between vehicles, maintaining vehicle speed, warning of vehicle collisions, or warning of vehicle lane departure.

[0082] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0083] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information about the outside of the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0084] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to passengers in the vehicle or to the outside of the vehicle. In the example of Fig. 12, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0085] FIG. 13 is a diagram showing an example of the installation position of the imaging unit 12031.

[0086] In FIG. 13, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.

[0087] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0088] 13 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

[0089] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

[0090] For example, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104, thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (for example, 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of automatic driving, which runs autonomously without relying on driver operation.

[0091] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drivetrain control unit 12010.

[0092] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the images captured by the image capturing units 12101 to 12104. The pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104, which are infrared cameras, and then performing pattern matching on a series of feature points that indicate the outline of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0093] An example of a mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 of the above-described configuration. Specifically, the solid-state imaging device 1 according to the above-described embodiment and its modified example can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to obtain a highly sensitive captured image, thereby enabling high-precision control using the captured image in the mobile object control system.

[0094] [Application example 2] FIG. 14 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0095] 14 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment instrument 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0096] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0097] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens towards an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0098] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected onto the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0099] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102, and performs various image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0100] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0101] The light source device 11203 is configured from a light source such as an LED (Light Emitting Diode), and supplies irradiation light to the endoscope 11100 when photographing an operation site or the like.

[0102] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiating light, magnification, focal length, etc.) of the endoscope 11100.

[0103] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0104] The light source device 11203 that supplies illumination light to the endoscope 11100 when photographing the surgical site can be configured from a white light source configured from, for example, an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, making it possible to adjust the white balance of the captured image in the light source device 11203. In this case, it is also possible to capture images corresponding to each RGB in a time-division manner by irradiating the object of observation with laser light from each RGB laser light source in a time-division manner and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0105] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free of so-called blocked-up shadows and blown-out highlights.

[0106] The light source device 11203 may also be configured to supply light in a predetermined wavelength band corresponding to special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light with a narrower band than the light irradiated during normal observation (i.e., white light), thereby capturing high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, known as narrow-band imaging. Alternatively, special light observation may be performed using fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation can involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (autofluorescence observation), or locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0107] FIG. 15 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0108] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other by a transmission cable 11400 so that they can communicate with each other.

[0109] The lens unit 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0110] The imaging unit 11402 is configured with an imaging element. The imaging element constituting the imaging unit 11402 may be one (a so-called single-chip type) or multiple (a so-called multi-chip type). When the imaging unit 11402 is configured with a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured with a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. 3D display enables the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is configured with a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0111] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0112] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0113] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0114] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0115] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0116] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0117] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0118] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0119] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data sent from the camera head 11102 .

[0120] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0121] Furthermore, the control unit 11413 causes the display device 11202 to display a captured image showing the surgical site, etc., based on the image signal that has been image processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0122] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for communication of electrical signals, an optical fiber for optical communication, or a composite cable of these.

[0123] In the illustrated example, communication is performed by wire using the transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0124] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. Of the configurations described above, the technology according to the present disclosure can be suitably applied to the imaging unit 11402 provided in the camera head 11102 of the endoscope 11100. By applying the technology according to the present disclosure to the imaging unit 11402, it is possible to obtain highly sensitive captured images, thereby providing a high-definition endoscope 11100.

[0125] The present disclosure has been described above by way of embodiments, their modifications, application examples, and applied examples. However, the present disclosure is not limited to the above-described embodiments, etc., and various modifications are possible. Note that the effects described in this specification are merely examples. The effects of the present disclosure are not limited to the effects described in this specification. The present disclosure may have effects other than those described in this specification.

[0126] The present disclosure can also be configured as follows. (1) a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance section formed on the first Si substrate and holding a signal voltage generated by the electrical signal; Equipped with Solid-state imaging device. (2) a readout unit that reads out the reset voltage from the first capacitance unit and the signal voltage from the second capacitance unit; The first capacitance section and the second capacitance section are connected to a signal path branching from the floating diffusion region to the readout section. The solid-state imaging device according to (1). (3) a readout unit that reads out the reset voltage from the first capacitance unit and the signal voltage from the second capacitance unit; the first capacitance section is connected to a signal path branched from the floating diffusion region to the readout section, The second capacitance section is inserted in series in the signal path. The solid-state imaging device according to (1). (4) a first readout unit that reads out the reset voltage from the first capacitance unit; a second readout unit that reads out the signal voltage from the second capacitance unit; Further provided with the first capacitance section is connected to a first signal path branching from the floating diffusion region to the first readout section, The second capacitance section is connected to a second signal path branching from the floating diffusion region to the second readout section. The solid-state imaging device according to (1). (5) The signal path further includes an amplifier circuit between the floating diffusion region and the first capacitance section and the second capacitance section, the amplifier circuit amplifying the electrical signal. (2) A solid-state imaging device. (6) The signal path further includes an amplifier circuit between the floating diffusion region and the first capacitance section and the second capacitance section, the amplifier circuit amplifying the electrical signal. (3) A solid-state imaging device according to (3). (7) a path between the floating diffusion region and the first capacitance section in the first signal path and a path between the floating diffusion region and the second capacitance section in the second signal path have a common path; The solid-state imaging device further includes a circuit inserted in the common path for amplifying the electrical signal. (4) A solid-state imaging device according to (4). (8) The photoelectric conversion region is formed in an InGaAs layer. The solid-state imaging device according to any one of (1) to (7). (9) The photoelectric conversion region is formed in an organic photoelectric conversion layer, a Ge layer, a SiGe layer, an amorphous silicon layer, or a quantum dot layer. The solid-state imaging device according to any one of (1) to (7). (10) a first pad electrode formed on a surface of the semiconductor layer facing the first Si substrate and electrically connected to the floating diffusion region; a second pad electrode formed on a surface of the first Si substrate on the semiconductor layer side and electrically connected to the first capacitance portion and the second capacitance portion; Further provided with The first pad electrode and the second pad electrode are connected by being attached to each other. The solid-state imaging device according to any one of (1) to (9). (11) The readout section is formed on the first Si substrate. (2) A solid-state imaging device. (12) The readout section is formed on the first Si substrate. (3) A solid-state imaging device according to (3). (13) The first readout section and the second readout section are formed on the first Si substrate. (4) A solid-state imaging device according to (4). (14) a second Si substrate on which the readout unit is formed and which is formed separately from the first Si substrate; a third pad electrode formed on a surface of the first Si substrate facing the second Si substrate and electrically connected to the first capacitance portion and the second capacitance portion; a fourth pad electrode formed on a surface of the second Si substrate facing the first Si substrate and electrically connected to the readout unit; Further provided with The third pad electrode and the fourth pad electrode are connected by being attached to each other. (2) A solid-state imaging device. (15) a second Si substrate on which the readout unit is formed and which is formed separately from the first Si substrate; a third pad electrode formed on a surface of the first Si substrate facing the second Si substrate and electrically connected to the first capacitance portion and the second capacitance portion; a fourth pad electrode formed on a surface of the second Si substrate facing the first Si substrate and electrically connected to the readout unit; Further provided with The third pad electrode and the fourth pad electrode are connected by being attached to each other. (3) A solid-state imaging device according to (3). (16) a second Si substrate on which the first readout section and the second readout section are formed and which is formed separately from the first Si substrate; a fifth pad electrode formed on a surface of the first Si substrate facing the second Si substrate and electrically connected to the first capacitance portion; a sixth pad electrode formed on a surface of the first Si substrate facing the second Si substrate and electrically connected to the second capacitance section; a seventh pad electrode formed on a surface of the second Si substrate facing the first Si substrate and electrically connected to the first readout unit; an eighth pad electrode formed on a surface of the second Si substrate facing the first Si substrate and electrically connected to the second readout unit; Further provided with the fifth pad electrode and the seventh pad electrode are joined by being attached to each other; The sixth pad electrode and the eighth pad electrode are joined by being attached to each other. (4) A solid-state imaging device according to (4). (17) a solid-state imaging device; the solid-state imaging device, a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance section formed on the first Si substrate and holding a signal voltage generated by the electrical signal; have electronic equipment. (18) a solid-state imaging device; the solid-state imaging device, a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance section formed on the first Si substrate and holding a signal voltage generated by the electrical signal; have Mobile object.

[0127] In a solid-state imaging device, an electronic device, and a mobile object according to an embodiment of the present disclosure, two capacitance units (a first capacitance unit and a second capacitance unit) are formed on a Si substrate. This allows noise contained in the signal voltage to be removed, for example, by calculating the difference between the reset voltage held in the first capacitance unit and the signal voltage held in the second capacitance unit. As a result, kTC noise can be suppressed. Furthermore, in the present disclosure, a floating diffusion region is provided in the semiconductor layer separately from a photoelectric conversion region, and charges generated in the floating diffusion region are transferred to the floating diffusion region. Here, noise can be removed by the two capacitance units provided downstream of the floating diffusion region, allowing the capacitance of the floating diffusion region to be reduced. This increases conversion efficiency and improves the signal-to-noise ratio. Therefore, a global shutter system can be adopted while achieving a high signal-to-noise ratio.

[0128] This application claims priority based on Japanese Patent Application No. 2021-077975, filed on April 30, 2021, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0129] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance portion formed on the first Si substrate and configured to hold a signal voltage generated by the electrical signal; a readout unit that reads out the reset voltage from the first capacitance unit and the signal voltage from the second capacitance unit; Equipped with the second capacitance section is inserted in series in a signal path from the floating diffusion region to the readout section, The first capacitance section is connected to the signal path in a branched manner. Solid-state imaging device.

2. The signal path further includes an amplifier circuit between the floating diffusion region and the first capacitance section and the second capacitance section, the amplifier circuit amplifying the electrical signal. The solid-state imaging device according to claim 1 .

3. The photoelectric conversion region is formed in an InGaAs layer. The solid-state imaging device according to claim 1 .

4. The photoelectric conversion region is formed in an organic photoelectric conversion layer, a Ge layer, a SiGe layer, an amorphous silicon layer, or a quantum dot layer. The solid-state imaging device according to claim 1 .

5. a first pad electrode formed on a surface of the semiconductor layer facing the first Si substrate and electrically connected to the floating diffusion region; a second pad electrode formed on a surface of the first Si substrate on the semiconductor layer side and electrically connected to the first capacitance portion and the second capacitance portion; Further provided with The first pad electrode and the second pad electrode are connected by being attached to each other. The solid-state imaging device according to claim 1 .

6. The readout section is formed on the first Si substrate. The solid-state imaging device according to claim 1 .

7. a second Si substrate on which the readout section is formed and which is formed separately from the first Si substrate; a third pad electrode formed on a surface of the first Si substrate facing the second Si substrate and electrically connected to the first capacitance portion and the second capacitance portion; a fourth pad electrode formed on a surface of the second Si substrate facing the first Si substrate and electrically connected to the readout unit; Further provided with The third pad electrode and the fourth pad electrode are joined by being attached to each other. The solid-state imaging device according to claim 1 .

8. a solid-state imaging device; the solid-state imaging device, a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance portion formed on the first Si substrate and configured to hold a signal voltage generated by the electrical signal; a readout unit that reads out the reset voltage from the first capacitance unit and the signal voltage from the second capacitance unit; and the second capacitance section is inserted in series in a signal path from the floating diffusion region to the readout section, The first capacitance section is connected to the signal path in a branched manner. electronic equipment.

9. a solid-state imaging device; the solid-state imaging device, a semiconductor layer stacked on a first Si substrate, the semiconductor layer including a photoelectric conversion region having a predetermined wavelength selectivity and a floating diffusion region that converts charges transferred from the photoelectric conversion region into an electrical signal and outputs the electrical signal; a first capacitance section formed on the first Si substrate and configured to hold a reset voltage of the floating diffusion region when the voltage of the floating diffusion region is reset; a second capacitance portion formed on the first Si substrate and configured to hold a signal voltage generated by the electrical signal; a readout unit that reads out the reset voltage from the first capacitance unit and the signal voltage from the second capacitance unit; and the second capacitance section is inserted in series in a signal path from the floating diffusion region to the readout section, The first capacitance section is connected to the signal path in a branched manner. Mobile object.

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