OPTICAL DETECTION UNIT, ELECTRONIC DEVICE AND OPTICAL DETECTION SYSTEM

Abstract

An optical detection unit according to an embodiment of the present disclosure comprises: a first photoelectric transducer that photoelectrically converts a wavelength component in a visible light range; a second photoelectric transducer that photoelectrically converts a wavelength component in a near-infrared range, wherein the second photoelectric transducer is stacked on top of the first photoelectric transducer;and a first wiring layer provided between the first photoelectric converter and the second photoelectric converter, wherein the first wiring layer comprises one or more wires formed using a material that transmits a wavelength component in a longer wavelength region than the visible light region, wherein the one or more wires are used to read out charges generated by photoelectric conversion in the first photoelectric converter.

Description

Photodetection device and electronic device, and photodetection system

[0001] The present disclosure relates to, for example, a photodetector device in which photoelectric conversion elements are stacked with wiring layers between, an electronic device, and a photodetection system.

[0002] For example, Patent Document 1 discloses an imaging element in which photoelectric conversion elements are stacked with wiring layers interposed therebetween.

[0003] JP 2013-70030 A

[0004] Incidentally, as described above, there is a demand for improved image quality in a photodetector device in which photoelectric conversion elements are stacked with wiring layers between them.

[0005] It would be desirable to provide photodetection devices, electronic devices, and photodetection systems that can improve image quality in both the visible and near-infrared regions.

[0006] An optical detection device according to one embodiment of the present disclosure includes a first photoelectric conversion unit that performs photoelectric conversion of wavelength components in the visible light region, a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and performs photoelectric conversion of wavelength components in the near-infrared region, and a first wiring layer that is provided between the first and second photoelectric conversion units and includes one or more wirings formed using a material that transmits wavelength components in a wavelength region longer than the visible light region, and that is used to read out electric charges generated by photoelectric conversion in the first photoelectric conversion unit.

[0007] An electronic device according to an embodiment of the present disclosure includes the photodetector according to the embodiment of the present disclosure.

[0008] An optical detection system according to one embodiment of the present disclosure includes a light source unit that emits near-infrared light and an optical detection device that detects ambient light and near-infrared light reflected from a subject, and includes the optical detection device according to one embodiment of the present disclosure as the optical detection device.

[0009] In a photodetector according to an embodiment of the present disclosure, an electronic device according to an embodiment, and a photodetection system according to an embodiment, one or more wirings included in a first wiring layer provided between a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region and a second photoelectric conversion unit that photoelectrically converts wavelength components in the near-infrared region are formed using a material that transmits wavelength components in a region longer than the visible light region, thereby reducing attenuation of light incident on the second photoelectric conversion unit.

[0010] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to an embodiment of the present disclosure. FIG. 2 is a plan view schematically illustrating an example of a configuration of the photodetector shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating an example of a manufacturing method of the photodetector shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating a step subsequent to FIG. 3A. FIG. 3 is a cross-sectional view schematically illustrating a step subsequent to FIG. 3B. FIG. 4 is a cross-sectional view schematically illustrating another example of a manufacturing method of the photodetector shown in FIG. 1. FIG. 4 is a cross-sectional view schematically illustrating a step subsequent to FIG. 4B. FIG. 4 is a cross-sectional view schematically illustrating a step subsequent to FIG. 4C. FIG. 5 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to Modification 1 of the present disclosure. FIG. 6 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to Modification 2 of the present disclosure. FIG. 6 is a cross-sectional view schematically illustrating an example of a manufacturing method of the photodetector shown in FIG. 7A. FIG. 7B. FIG. 7 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to Modification 3 of the present disclosure. FIG. 8 is a cross-sectional view schematically illustrating an example of a manufacturing method of the photodetector shown in FIG. 9A. FIG. 9B. 25A is a schematic cross-sectional view showing a step subsequent to FIG. 9C. FIG. 25B is a schematic cross-sectional view showing a step subsequent to FIG. 9D. FIG. 25C is a schematic cross-sectional view showing a step subsequent to FIG. 9E. FIG. 25D is a schematic cross-sectional view showing a step subsequent to FIG. 9E. FIG. 25E is a schematic cross-sectional view explaining another example of a manufacturing method for the light detection device shown in FIG. 8. FIG. 25A is a schematic cross-sectional view showing a step subsequent to FIG. 10A. FIG. 25B is a schematic cross-sectional view showing a step subsequent to FIG. 10C. FIG. 25C is a schematic cross-sectional view showing a step subsequent to FIG. 10E. FIG. 25F is a schematic cross-sectional view showing a step subsequent to FIG. 10F. FIG. 25A is a block diagram showing an overall configuration of the light detection device shown in FIG. 1 etc. FIG. 25B is a block diagram showing an example of the configuration of an electronic device using the light detection device shown in FIG. 23. FIG. 25B is a schematic diagram showing an example of the overall configuration of a light detection system using the light detection device shown in FIG. 23. FIG. 25A is a diagram showing an example of the circuit configuration of the light detection system shown in FIG. 25A. FIG. 25B is a diagram showing an example of a schematic configuration of an endoscopic surgery system. FIG. 25C is a block diagram showing an example of the functional configuration of a camera head and a CCU. FIG. 25D is a block diagram showing an example of a schematic configuration of a vehicle control system. FIG. 25C is an explanatory diagram showing an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0011] An embodiment of the present disclosure will be described in detail below with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of the components shown in the drawings. The order of description is as follows: 1. Embodiment (an example in which wiring in a wiring layer between stacked light receiving sections is formed using polysilicon) 1-1. Configuration of a photodetector 1-2. Method for manufacturing a photodetector 1-3. Actions and effects 2. Modifications 2-1. Modification 1 (an example in which a bandpass filter is arranged between stacked light receiving sections) 2-2. Modification 2 (an example in which a readout circuit and a logic circuit are provided on different substrates and stacked) 2-3. Modification 3 (an example in which a near-infrared light receiving section is formed using black silicon) 3. Application examples 4. Application examples

[0012] 1. Embodiment Fig. 1 schematically illustrates an example of a cross-sectional configuration of a photodetector (photodetector 1) according to an embodiment of the present disclosure. Fig. 2 schematically illustrates an example of a planar configuration of the photodetector 1 illustrated in Fig. 1. The photodetector 1 is used in, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras, or a range image sensor that measures distance using a ToF (Time-of-Flight) method.

[0013] The photodetector 1 is configured such that a light receiving section 10 including a photoelectric conversion section 12 that photoelectrically converts wavelength components in the visible light region, and a light receiving section 30 including a photoelectric conversion section 32 that photoelectrically converts wavelength components in the near-infrared region are stacked in this order from the light incident side with a wiring layer 20 in between. In the photodetector 1 of this embodiment, one or more wirings formed in the wiring layer 20 are formed using a material (for example, polysilicon (Poly-Si)) that transmits wavelength components in a region longer than the visible light region.

[0014] (1-1. Configuration of the Photodetector) The photodetector 1 is formed by stacking a light receiving section 10, a wiring layer 20, a light receiving section 30, a wiring layer 40, a wiring layer 50, and a circuit board 60 in this order from the light incident side. In this embodiment, the light receiving section 10 has a photoelectric conversion section 12 formed on a silicon substrate 11, which photoelectrically converts wavelength components in the visible light region, and the light receiving section 30 has a photoelectric conversion section 32 formed embedded in a silicon substrate 31, which photoelectrically converts wavelength components in the near-infrared region. The wiring layer 20 is provided with one or more wirings (e.g., gate wiring 22 and wiring 23), and these one or more wirings (e.g., gate wiring 22 and wiring 23) are formed using a material (e.g., polysilicon (Poly-Si)) that transmits wavelength components in a region longer than the visible light region. A color filter 14 and an on-chip lens 15 are arranged on the light incident side of the light receiving section 10.

[0015] The light receiving unit 10 includes a silicon substrate 11 and a photoelectric conversion unit 12 formed for each unit pixel P (see FIG. 11 ) that photoelectrically converts wavelength components in the visible light region. The photoelectric conversion unit 12 corresponds to a specific example of a "first photoelectric conversion unit" in the present disclosure. The photoelectric conversion unit 12 is, for example, a PIN (Positive Intrinsic Negative) photodiode PD, and has a pn junction in a predetermined region of the silicon substrate 11. The silicon substrate 11 has a first surface 11S1 that serves as a light incident surface and a second surface 11S2 opposite to the first surface 11S1.

[0016] The silicon substrate 11 has an isolation portion 13 between adjacent unit pixels P. Specifically, the isolation portion 13 is provided in a lattice pattern surrounding each unit pixel P in the pixel section 100A in which a plurality of unit pixels P are arranged in an array in the row and column directions. The isolation portion 13 serves to electrically isolate adjacent unit pixels P. The isolation portion 13 has, for example, a full trench isolation (FTI) structure that penetrates between the first surface 11S1 and the second surface 11S2 of the silicon substrate 11. Alternatively, the isolation portion 13 may have, for example, a deep trench isolation (DTI) structure or a shallow trench isolation (STI) structure that extends from one surface (e.g., the first surface 11S1) of the silicon substrate 11 to the other surface (e.g., the second surface 11S2) and has a bottom within the silicon substrate 11.

[0017] The isolation portion 13 is made of, for example, silicon oxide (SiO ｘ ) film. Alternatively, a light-shielding film may be embedded in the insulating film in the isolation portion 13. This allows the adjacent unit pixels P to be electrically and optically isolated from each other.

[0018] Although not shown, a floating diffusion FD and a transfer transistor TR that outputs signal charges output from each unit pixel P to a readout circuit are provided on the second surface 11S2 of the silicon substrate 11.

[0019] On the first surface 11S1 side of the silicon substrate 11, color filters 14 (14R, 14G, 14B) are provided for each unit pixel P. The color filters 14 selectively transmit red light (R) having a wavelength of, for example, 570 nm or more and 700 nm or less, green light (G) having a wavelength of, for example, 460 nm or more and 600 nm or less, and blue light (B) having a wavelength of, for example, 400 nm or more and 520 nm or less. Specifically, as shown in FIG. 2, for example, four unit pixels P are arranged in two rows and two columns, with two green pixels Pg arranged on a diagonal line and a red pixel Pr and a blue pixel Pb arranged on a diagonal line perpendicular to the diagonal line. Each color filter 14R, 14G, 14B is arranged for a corresponding color pixel Pr, Pg, Pb, thereby photoelectrically converting the corresponding color light in each color pixel Pr, Pg, Pb. That is, in the pixel section 100A, unit pixels P (red pixel Pr, green pixel Pg, and blue pixel Pb) that photoelectrically convert red light (R), green light (G), and blue light (B) are arranged in a Bayer pattern.

[0020] An on-chip lens 15 is provided on the color filter 14. The on-chip lens 15 focuses light incident from above onto the photoelectric conversion units 12 and 32. For example, the on-chip lens 15 is made of silicon oxide (SiO ｘ ) The on-chip lens 15 may be provided for each unit pixel P, for example, or may be provided for each of a plurality of unit pixels P (for example, four unit pixels P arranged in two rows and two columns as described above).

[0021] A wiring layer 20 is provided on the second surface 11S2 side of the silicon substrate 11. In the wiring layer 20, one or more wirings are provided in an interlayer insulating layer 21. The one or more wirings include a gate wiring 22 such as the gate of the transfer transistor TR, and a wiring 23 for supplying a voltage to be applied to the silicon substrate 11 and the photoelectric conversion unit 12 and extracting charges generated in the photoelectric conversion unit 12.

[0022] The gate wiring 22, wiring 23, and other components formed within the interlayer insulating layer 21, including the vias electrically connecting the wiring components, are formed using a material that transmits wavelength components in a wavelength range longer than the visible light range. An example of such a material is polysilicon (Poly-Si). The gate wiring 22, wiring 23, and other components formed within the interlayer insulating layer 21 are electrically connected to a circuit board 60 (described later) via a plurality of through-wires 33 that penetrate the light-receiving unit 30.

[0023] The light receiving unit 30 includes, for example, a semiconductor substrate embedded in a silicon substrate 31 and a photoelectric conversion unit 32 provided thereon. The photoelectric conversion unit 32 corresponds to a specific example of a "second photoelectric conversion unit" in the present disclosure. The semiconductor substrate corresponds to a specific example of a "semiconductor substrate" in the present disclosure, and is, for example, a Ge substrate containing germanium (Ge), a compound semiconductor substrate of silicon (Si) and Ge (e.g., a SiGe substrate), or an In.Ga.As substrate containing indium (In).gallium (Ga).arsenic (As). The semiconductor substrate has a third surface 32S1 facing the second surface 11S2 of the silicon substrate 11 and a fourth surface 32S2 opposite the third surface 32S1.

[0024] The photoelectric conversion units 32 are arranged so that their centers, in a plan view, substantially coincide with the intersections of four photoelectric conversion units 12 arranged in a 2-row by 2-column array, as shown in Fig. 2. That is, for example, the IR pixels Pir that photoelectrically convert wavelength components in the near-infrared region of 1100 nm or more are arranged one for each of four color pixels (one red pixel Pr, one blue pixel Pb, and two green pixels Pg) arranged in a 2-row by 2-column array. Note that the arrangement of the IR pixels Pir is not limited to this, and for example, one IR pixel Pir may be arranged for each of 16 color pixels arranged in a 4-row by 4-column array.

[0025] A plurality of through-wires 33 penetrate the light receiving section 30, electrically connecting the gate wiring 22, wiring 23, etc. provided in the wiring layer 20 to the circuit board 60. The through-wires 33 are formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). The plurality of through-wires 33 are provided, for example, at the four corners of the photoelectric conversion section 32, or, as shown in FIG. 2, for example, so as to surround the photoelectric conversion section 32. This makes it possible to reduce the intrusion of obliquely incident light from adjacent pixels.

[0026] The semiconductor substrate constituting the photoelectric conversion unit 32 can be formed, for example, by providing an opening of a predetermined depth in the silicon substrate 31 and growing a semiconductor layer in the opening using an epitaxial crystal growth method. The photoelectric conversion unit 32 is not limited to being formed in the silicon substrate 31, and may be formed, for example, embedded in an insulating layer 34 (see, for example, FIG. 4C ). Alternatively, the silicon substrate 31 may be left only in a portion facing the fourth surface 32S2 of the photoelectric conversion unit 32, and the periphery of the photoelectric conversion unit 32 and the silicon substrate 31 may be embedded in the insulating layer 34. The insulating layer 34 may be formed, for example, in silicon oxide (SiO ｘ ), TEOS, silicon nitride (SiN ｘ ) and silicon oxynitride (SiO ｘ N ｙ ) or a laminated film made of two or more of these.

[0027] A wiring layer 40 is provided on the fourth surface 32S2 side of the photoelectric conversion unit 32. The wiring layer 40 includes one or more wirings provided within an interlayer insulating layer 41. The one or more wirings are, for example, wirings 42 for supplying voltages to be applied to the through wirings 33 and the photoelectric conversion unit 32, or for extracting charges generated in the photoelectric conversion unit 32. Like the through wirings 33, the wirings 42 are formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). One or more pad portions 43 are further embedded in the interlayer insulating layer 41 and are exposed on the surface of the interlayer insulating layer 41. The one or more pad portions 43 are formed using, for example, copper (Cu).

[0028] A circuit board 60, on which a wiring layer 50 is further provided, is disposed on the fourth surface 32S2 side of the photoelectric conversion unit 32. The circuit board 60 corresponds to a specific example of a "circuit board" in the present disclosure. The circuit board 60 is provided with a readout circuit including, for example, a reset transistor, an amplification transistor, and a selection transistor, which generates pixel signals based on signal charges generated by photoelectric conversion of each photoelectric conversion unit 12 and each photoelectric conversion unit 32, and a logic circuit which processes the pixel signals output from the readout circuit. One or more pad units 52 are further embedded in the interlayer insulating layer 51 and are exposed on the surface of the interlayer insulating layer 51. The one or more pad units 52 are formed using, for example, copper (Cu).

[0029] In the photodetector 1, for example, CuCu bonding is performed between one or more pad portions 43 exposed on the surface of the wiring layer 40 and one or more pad portions 52 exposed on the surface of the wiring layer 50. As a result, the light receiving portion 10 and the light receiving portion 30 are electrically connected to the circuit board 60.

[0030] (1-2. Method for Manufacturing Photodetector) The photodetector 1 can be manufactured, for example, as follows: Figures 3A to 3C show an example of a method for manufacturing the photodetector 1 in the order of steps.

[0031] First, a light-receiving section 10 having a photoelectric conversion section 12 and an isolation section 13 formed therein is formed in a silicon substrate 11. Then, a wiring layer 20 including wiring (gate wiring 22 and wiring 23) formed using polysilicon is provided on the second surface 11S2 side of the silicon substrate 11. A silicon substrate 31 is bonded to a support substrate 81. An opening having a predetermined depth is formed in the silicon substrate 31. A semiconductor layer made of, for example, germanium (Ge) is then formed in the opening by epitaxial crystal growth, such as metal organic chemical vapor deposition (MOCVD). The photoelectric conversion section 32 is then formed by controlling the p-type or n-type impurity concentration by, for example, ion implantation, to form the light-receiving section 30. These are then bonded together, with the wiring layer 20 and the light-receiving section 30 facing each other, as shown in FIG. 3A .

[0032] 3B , the support substrate 81 is removed, and the silicon substrate 31 is thinned to a predetermined thickness, and then the silicon substrate 31 is etched to form through-holes that reach the wiring 23. Thereafter, a metal material such as aluminum (Al) is embedded in the through-holes by, for example, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, an atomic layer deposition (ALD) method, or a vapor deposition method, to form contact vias and the like that are connected to the through-wiring 33 and the photoelectric conversion unit 32.

[0033] Next, after planarizing the surface of the silicon substrate 31 by, for example, CMP (Chemical Mechanical Polishing), a wiring layer 40 including wiring 42 and pad portions 43 is formed on the silicon substrate 31. Next, as shown in FIG. 3C , for example, the wiring layer 50 of a circuit substrate 60 having a separately formed wiring layer 50 is arranged opposite the wiring layer 40, and the pad portions 43, 52 are bonded and attached. Thereafter, a color filter 14 and an on-chip lens 15 are formed in this order on the first surface 11S1 side of the silicon substrate 11. This completes the photodetector 1 shown in FIG. 1 .

[0034] 4A to 4D show another example of a method for manufacturing the photodetector 1 in the order of steps.

[0035] As in the above-described manufacturing method, first, a light receiving section 10 having a photoelectric conversion section 12 and an isolation section 13 formed therein is formed in a silicon substrate 11, and then a wiring layer 20 including wiring (gate wiring 22 and wiring 23) formed using polysilicon is provided on the second surface 11S2 side of the silicon substrate 11. Furthermore, a semiconductor layer 32A made of, for example, germanium (Ge) is formed on the silicon substrate 82 by an epitaxial crystal growth method such as MOCVD. These are then bonded together with the wiring layer 20 and the semiconductor layer 32A facing each other, as shown in FIG. 4A .

[0036] 4B, the silicon substrate 82 is removed, and the semiconductor layer 32A is processed by etching, and then the p-type or n-type impurity concentration is controlled by, for example, ion implantation to form the photoelectric conversion unit 32. Subsequently, as shown in FIG. 4C, an insulating layer 34 is formed by, for example, a CVD method so as to bury the photoelectric conversion unit 32.

[0037] Next, as shown in FIG. 4D , the insulating layer 34 is etched to form through-holes reaching the wiring 23. Then, a metal material such as aluminum (Al) is embedded in the through-holes by, for example, CVD, PVD, ALD, or vapor deposition to form the through-holes 33 and contact vias connected to the photoelectric conversion unit 32. Then, similar to the manufacturing method described above, the surface of the insulating layer 34 is planarized by, for example, CMP, and a wiring layer 40 including wiring 42 and pad portions 43 is formed on the insulating layer 34. Next, the wiring layer 50 of a circuit board 60 having a separately formed wiring layer 50 is placed face-to-face with the wiring layer 40, and the pad portions 43 and 52 are bonded and bonded together. Finally, a color filter 14 and an on-chip lens 15 are formed in this order on the first surface 11S1 of the silicon substrate 11. This completes the photodetector 1 in which the photoelectric conversion unit 32 is embedded in the insulating layer 34.

[0038] (1-3. Actions and Effects) In the photodetector 1 of this embodiment, one or more wires included in the wiring layer 20 provided between the stacked light receiving section 10 including the photoelectric conversion section 12 that photoelectrically converts wavelength components in the visible light region and the light receiving section 30 including the photoelectric conversion section 32 that photoelectrically converts wavelength components in the near-infrared region are formed using a material that transmits wavelength components in a region longer than the visible light region. This reduces the reduction in light incident on the photoelectric conversion section 32. This is described below.

[0039] In recent years, photodetection devices (e.g., solid-state imaging devices) in which multiple sensors are stacked have been proposed to obtain a variety of photoelectric conversion outputs. However, in solid-state imaging devices with a typical stacked structure, as the number of pixels in the upper sensor closer to the light incident side increases, the wiring density of the wiring layer formed below the upper sensor increases, resulting in a problem that the amount of light incident on the lower sensor decreases, resulting in a deterioration in the image quality of the lower sensor.

[0040] In contrast to this, in the present embodiment, the wiring layer 20 is provided between the light receiving unit 10 including the photoelectric conversion unit 12 that photoelectrically converts wavelength components in the visible light region and the light receiving unit 30 including the photoelectric conversion unit 32 that photoelectrically converts wavelength components in the near-infrared region, which are stacked in this order from the light incident side. For example, the gate wiring 22 and wiring 23 included in the wiring layer 20 are formed using, for example, polysilicon that transmits wavelength components in a region longer than the visible light region. This reduces the reduction in light incident on the photoelectric conversion unit 32 due to reflection and absorption by the gate wiring 22, wiring 23, and vias connecting them.

[0041] As described above, in the photodetector 1 of this embodiment, it is possible to improve the image quality of the light receiving unit 30 (IR sensor) including the photoelectric conversion unit 32 that photoelectrically converts wavelength components in the near-infrared region, which is disposed below the light receiving unit 10 (visible light sensor) including the photoelectric conversion unit 12 that photoelectrically converts wavelength components in the visible light region. Furthermore, it is possible to miniaturize and increase the number of pixels in the red pixel Pr, green pixel Pg, and blue pixel Pb provided in the light receiving unit 10, and it is also possible to improve the image quality of the light receiving unit 10 (visible light sensor).

[0042] Furthermore, in this embodiment, a plurality of through-wires 33 are provided around the IR pixel Pir (a photoelectric conversion unit 32 that photoelectrically converts wavelength components in the infrared region) to electrically connect the gate wiring 22, wiring 23, etc. to the circuit board 60, thereby making it possible to reduce the intrusion of obliquely incident light from adjacent pixels.

[0043] Next, modifications 1 to 3 of the present disclosure will be described. In the following, the same components as those in the above embodiment will be given the same reference numerals, and the description thereof will be omitted as appropriate.

[0044] 2. Modifications (2-1. Modification 1) FIG. 5 is a schematic diagram illustrating an example of a cross-sectional configuration of a light detection device (light detection device 2) according to Modification 1 of the present disclosure.

[0045] A bandpass filter 35 having a transmission band in the near-infrared light region may be provided between the red pixel Pr, the green pixel Pg, and the blue pixel Pb and the IR pixel Pir. For example, the bandpass filter 35 may be provided between the wiring layer 20 and the light receiving unit 30. This suppresses the incidence of visible light (e.g., red light (R) on the long wavelength side) that has not been fully absorbed by the photoelectric conversion unit 12. In other words, color mixing of visible light in the IR pixel Pir is reduced.

[0046] Note that the IR pixel Pir may be corrected in accordance with the output of the red pixel Pr instead of the band-pass filter 35. This makes it possible to prevent color mixing between adjacent pixels caused by visible light reflected by the band-pass filter 35 entering the adjacent pixels.

[0047] 6 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 3) according to Modification 2 of the present disclosure. Photodetector 3 of this modification differs from the above embodiment in that the readout circuit and logic circuit formed on circuit board 60 are formed on separate boards (Readout Integrated Circuit (ROIC) board 60A and logic board 60B) and then stacked.

[0048] In the photodetector 3, a light receiving unit 10, a wiring layer 20, a light receiving unit 30, a wiring layer 40, a wiring layer 50A, an ROIC substrate 60A, a wiring layer 50B, a wiring layer 50C, and a logic substrate 60B are stacked in this order from the light incident side. The light receiving unit 10 has a photoelectric conversion unit 12 embedded in a silicon substrate 11 that photoelectrically converts wavelength components in the visible light range, and the light receiving unit 30 has a photoelectric conversion unit 32 embedded in a silicon substrate 31 that photoelectrically converts wavelength components in the near-infrared range. The wiring layer 20 is provided with one or more wirings (e.g., gate wiring 22 and wiring 23), which are formed using a material (e.g., polysilicon) that transmits wavelength components in a range longer than the visible light range. A color filter 14 and an on-chip lens 15 are arranged on the light incident side of the light receiving unit 10.

[0049] The ROIC substrate 60A is disposed on the fourth surface 32S2 side of the photoelectric conversion unit 32. The ROIC substrate 60A is provided with a plurality of readout circuits 53 that generate pixel signals based on signal charges generated by photoelectric conversion of each photoelectric conversion unit 12 and each photoelectric conversion unit 32. Specifically, for example, a wiring layer 50A having pad units 52 extending to the surface is provided on the surface of the ROIC substrate 60A facing the wiring layer 40, and a wiring layer 50B on which the readout circuits 53 are formed is provided on the surface opposite to the surface facing the wiring layer 40.

[0050] The logic substrate 60B is disposed on the fourth surface 32S2 side of the photoelectric conversion unit 32, with the ROIC substrate 60A in between. The logic substrate 60B is provided with a logic circuit and the like that processes pixel signals output from the readout circuit 53. Specifically, for example, a wiring layer 50C on which the logic circuit and the like are formed is provided on the surface of the logic substrate 60B facing the wiring layer 50B.

[0051] The ROIC substrate 60A and the logic substrate 60B are electrically connected to the light receiving unit 10 and the light receiving unit 30, respectively, by through-wires 54 and 55 that penetrate the ROIC substrate 60A. The through-wires 54 and 55 are formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W).

[0052] 7A to 7C show an example of a method for manufacturing the photodetector 3 in the order of steps.

[0053] The light receiving section 10, the wiring layer 20, the light receiving section 30, and the wiring layer 40 are formed, for example, in the same manner as in the above embodiment. The ROIC substrate 60A and the logic substrate 60B can be formed, for example, as follows: First, a wiring layer 50B including a readout circuit 53 is formed on the ROIC substrate 60A, and a wiring layer 50C including a logic circuit and the like is formed on the logic substrate 60B. Then, as shown in FIG. 7A , the wiring layer 50B and the wiring layer 50C are arranged opposite each other and bonded together.

[0054] Next, as shown in FIG. 7B , the ROIC substrate 60A is thinned to a predetermined thickness by, for example, CMP, and then through-hole wirings 54 and 55 are formed, penetrating the ROIC substrate 60A and reaching the wiring layers 50B and 50C. Subsequently, as shown in FIG. 7C , a wiring layer 50A including a pad portion 52 is formed on the ROIC substrate 60A, and then the wiring layer 40 formed on the previously formed light receiving portion 30 and the wiring layer 50A are arranged facing each other, and the pad portions 43 and 52 are bonded and attached. Thereafter, a color filter 14 and an on-chip lens 15 are formed in this order on the first surface 11S1 side of the silicon substrate 11. This completes the photodetector 3 shown in FIG. 6 .

[0055] As described above, in this modification, a plurality of readout circuits that generate pixel signals based on signal charges generated by photoelectric conversion of each photoelectric conversion unit 12 and each photoelectric conversion unit 32 are formed on the ROIC substrate 60A, and logic circuits and the like that process pixel signals output from the readout circuits 53 are formed on the logic substrate 60B, and the ROIC substrate 60A and the logic substrate 60B are stacked together. This enables further miniaturization and an increase in the number of pixels of the red pixels Pr, green pixels Pg, and blue pixels Pb. This makes it possible to further improve the image quality in both the visible light region and the near-infrared region.

[0056] 8 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 4) according to Modification 3 of the present disclosure. Photodetector 4 of this modification differs from the above-described embodiment in that, instead of the photodetector 30 of the above-described embodiment, a photodetector 70 is provided in which a photoelectric conversion unit 72 that photoelectrically converts wavelength components in the near-infrared region is formed in black silicon (Black-Si) that is embedded in a silicon substrate 71.

[0057] 9A to 9F show an example of a method for manufacturing the photodetector 4 in the order of steps.

[0058] First, pixel transistors 74 are formed on a surface 71S2 of a silicon substrate 71 bonded to a substrate (not shown), and then a wiring layer 40 is formed. Next, a support substrate 83 is bonded to the wiring layer 40, and the substrate bonded to the silicon substrate 71 is removed, and then the silicon substrate 71 is thinned from the surface 71S1 to a predetermined thickness.

[0059] Next, as shown in FIG. 9A, a black silicon region is formed on the surface 71S1 side of the silicon substrate 71 using, for example, dry etching or a laser, and the light receiving section 70 is formed using this black silicon region as the photoelectric conversion section 72.

[0060] Next, as shown in FIG. 9B , the pre-formed light-receiving section 10 provided with the wiring layer 20 is placed face-to-face with the light-receiving section 70 and bonded together. Subsequently, as shown in FIG. 9C , the support substrate 83 is removed, and an opening is formed that penetrates the silicon substrate 71 to reach the wiring 23 while avoiding the black silicon region (photoelectric conversion section 72). An oxide film (not shown) is then formed in the opening, and the oxide film at the bottom of the opening is etched back, after which the through-wiring 33 is formed. Next, as shown in FIG. 9D , an interlayer insulating layer 41 is further formed on the surface of the wiring layer 40, and one or more pad sections 43 are embedded in the surface.

[0061] Next, as shown in FIG. 9E, the wiring layer 50 of the previously formed logic substrate 60B and the wiring layer 40 are arranged facing each other, and the pad portions 43, 52 are bonded and attached. Next, as shown in FIG. 9F, the silicon substrate 11 of the light receiving portion 10 is thinned and flattened to a predetermined thickness by, for example, CMP. Thereafter, the color filter 14 and the on-chip lens 15 are formed in this order on the first surface 11S1 side of the silicon substrate 11. This completes the photodetector 4 shown in FIG. 8.

[0062] 10A to 10G show another example of a method for manufacturing the photodetector 4 in the order of steps.

[0063] 10A, a black silicon region is formed in a silicon substrate 71, for example, by dry etching or a laser, and then a p-type or n-type impurity concentration is controlled by, for example, ion implantation to provide a photoelectric conversion unit 72, thereby forming a light receiving unit 70. Next, as shown in FIG. 10B, an interlayer insulating layer 21 including a pinning film is formed on a surface 71S1 of the silicon substrate 71 on which the photoelectric conversion unit 72 is provided.

[0064] 10C, the light receiving section 10 provided with the wiring layer 20 formed in advance is placed and bonded together with the wiring layer 20 facing the interlayer insulating layer 21 provided on the light receiving section 70. Next, as shown in Fig. 10D, the silicon substrate 71 is thinned to a predetermined thickness by, for example, CMP, and then, as shown in Fig. 10E, pixel transistors 74 are formed on a surface 71S2 of the silicon substrate.

[0065] 10F, through-hole wiring 33 is formed, penetrating the silicon substrate 71 and reaching the wiring 23, and a wiring layer 40 is formed, in which one or more pad portions 43 are exposed on the surface. Next, as shown in FIG. 10G, the silicon substrate 11 of the light-receiving portion 10 is thinned to a predetermined thickness by, for example, CMP. Thereafter, a color filter 14 and an on-chip lens 15 are formed in this order on the first surface 11S1 side of the silicon substrate 11. This completes the photodetector 4 shown in FIG. 8. Although this manufacturing method imposes a thermal load on the light-receiving portion 10, which is provided with red pixels Pr, green pixels Pg, and blue pixels Pb, it is easier to manufacture than the above manufacturing method.

[0066] In this way, in this modification, the photoelectric conversion unit (photoelectric conversion unit 72) that photoelectrically converts wavelength components in the near-infrared region is formed on black silicon, which makes it possible to form pixel transistors 74 in the light receiving unit 70.

[0067] In this modification, an example in which black silicon is embedded in the silicon substrate 71 has been shown, but black silicon may be substituted for the silicon substrate 71. As in the above embodiment, the photoelectric conversion unit 72 may be embedded in an insulating layer, or only a portion of the silicon substrate 71 may be left, and the periphery of the photoelectric conversion unit 72 and the silicon substrate 71 may be embedded in an insulating layer.

[0068] 3. Application Examples Application Example 1 FIG. 11 shows an example of the overall configuration of the photodetector (for example, the photodetector 1) shown in FIG. 1 and the like.

[0069] The photodetector 1 is, for example, a CMOS image sensor that captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of incident light imaged on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the signal as a pixel signal. The photodetector 1 has a pixel section 100A as an imaging area on a silicon substrate 11, and also has, in a peripheral region of the pixel section 100A, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and input / output terminals 116.

[0070] The pixel section 100A has, for example, a plurality of unit pixels P arranged two-dimensionally in a matrix. For example, pixel drive lines Lread (specifically, row selection lines and reset control lines) are wired to each unit pixel P for each pixel row, and vertical signal lines Lsig are wired to each pixel column. The pixel drive lines Lread transmit drive signals for reading signals from the pixels. One end of each pixel drive line Lread is connected to an output terminal of the vertical drive circuit 111 corresponding to each row.

[0071] The vertical drive circuit 111 is a pixel drive unit that includes a shift register, an address decoder, etc., and drives each unit pixel P of the pixel unit 100A, for example, row by row. Signals output from each unit pixel P of a pixel row selected and scanned by the vertical drive circuit 111 are supplied to a column signal processing circuit 112 through each vertical signal line Lsig. The column signal processing circuit 112 is configured with an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

[0072] The horizontal drive circuit 113 is configured with a shift register, an address decoder, etc., and scans and sequentially drives each horizontal selection switch of the column signal processing circuit 112. By selective scanning by this horizontal drive circuit 113, signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to horizontal signal lines 121 and transmitted to the outside of the silicon substrate 11 through the horizontal signal lines 121.

[0073] The output circuit 114 processes and outputs signals sequentially supplied from each of the column signal processing circuits 112 via the horizontal signal line 121. The output circuit 114 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like, for example.

[0074] The circuit portion consisting of the vertical drive circuit 111, column signal processing circuit 112, horizontal drive circuit 113, horizontal signal line 121, and output circuit 114 may be formed directly on the silicon substrate 11, or may be disposed in an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0075] The control circuit 115 receives a clock and data instructing an operation mode from outside the silicon substrate 11, and outputs data such as internal information of the photodetector 1. The control circuit 115 further has a timing generator that generates various timing signals, and controls the driving of peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

[0076] The input / output terminal 116 is used to exchange signals with the outside.

[0077] (Application Example 2) Furthermore, the light detection device 1 as described above can be applied to various electronic devices, such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, or other devices with imaging functions.

[0078] FIG. 12 is a block diagram showing an example of the configuration of the electronic device 1000. As shown in FIG.

[0079] As shown in FIG. 12, the electronic device 1000 includes an optical system 1001, a photodetector 1, and a DSP (Digital Signal Processor) 1002. The DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 are connected via a bus 1008, and is capable of capturing still and moving images.

[0080] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from a subject and forms an image on the imaging surface of the photodetector 1 .

[0081] The above-described photodetector 1 is applied as the photodetector 1. The photodetector 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal to the DSP 1002 as a pixel signal.

[0082] The DSP 1002 performs various signal processing on the signal from the photodetector 1 to acquire an image, and temporarily stores the image data in the memory 1003. The image data stored in the memory 1003 is recorded in the recording device 1005 or supplied to the display device 1004 to display the image. In addition, the operation system 1006 accepts various operations by the user and supplies operation signals to each block of the electronic device 1000, and the power supply system 1007 supplies the power necessary to drive each block of the electronic device 1000.

[0083] 13A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 1. FIG. 13B is a diagram illustrating an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 serving as a light source unit that emits infrared light L2, and a light detection device 2002 serving as a light receiving unit having a photoelectric conversion element. The light detection device 1 described above can be used as the light detection device 2002. The light detection system 2000 may further include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0084] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by a subject (object to be measured) 2100 ( FIG. 13A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the subject 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be installed in, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 can be configured, for example, by a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can be, for example, an iTOF method, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100, for example, by using the time-of-flight (TOF) of light. The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can also be, for example, a structured light method or a stereo vision method. For example, in the structured light method, a predetermined pattern of light is projected onto the subject 2100, and the distance between the photodetector system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby measuring the distance between the photodetector system 2000 and the subject. The light emitting device 2001 and the light detecting device 2002 can be controlled synchronously by a system control unit 2003 .

[0085] 4. Application Example Application Example to Endoscopic Surgery System 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 applied to an endoscopic surgery system.

[0086] 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.

[0087] 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 tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0088] 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.

[0089] 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 toward 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.

[0090] 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.

[0091] 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 types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0092] 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.

[0093] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies irradiation light to the endoscope 11100 when photographing the surgical area, etc.

[0094] 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 irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0095] 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.

[0096] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as 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, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0097] 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 from so-called blocked-up shadows and blown-out highlights.

[0098] The light source device 11203 may also be configured to provide light in a predetermined wavelength range compatible with 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 involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light onto the body tissue. Fluorescence observation can involve irradiating excitation light onto the body tissue and observing the fluorescence from the tissue (autofluorescence observation), or by 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 provide narrow-band light and / or excitation light compatible with such special light observation.

[0099] 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.

[0100] 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 via a transmission cable 11400 so that they can communicate with each other.

[0101] The lens unit 11401 is an optical system provided at the connection portion 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.

[0102] The imaging unit 11402 may include one imaging element (a so-called single-chip type) or multiple imaging elements (a so-called multi-chip type). When the imaging unit 11402 is configured as 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 to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to a 3D (dimensional) display. The 3D display allows 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 as a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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 a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0108] 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 .

[0109] 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.

[0110] 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.

[0111] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0112] 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.

[0113] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing 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.

[0114] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0115] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0116] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the imaging unit 11402 among the components described above. By applying the technology according to the present disclosure to the imaging unit 11402, detection accuracy is improved.

[0117] Although an endoscopic surgery system has been described as an example here, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0118] (Application Example to Mobile Object) The technology according to the present disclosure 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 mobile object, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0119] FIG. 16 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.

[0120] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 16, 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.

[0121] 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, and a braking device for generating a braking force of the vehicle.

[0122] 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 can 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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 drive system 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 vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0127] 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.

[0128] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside 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 aimed at preventing glare, such as switching from high beams to low beams.

[0129] 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 vehicle occupants or the outside of the vehicle. In the example of Fig. 16, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0130] FIG. 17 is a diagram showing an example of the installation position of the imaging unit 12031.

[0131] In FIG. 17, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0132] 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 on the front nose and the imaging unit 12105 provided on 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 on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0133] 17 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, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0134] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0135] For example, based on the distance information obtained from the imaging units 12101 to 12104, 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), 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 (e.g., 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 autonomous driving, which runs autonomously without relying on driver operation.

[0136] 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 a collision risk that indicates the 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 drive system control unit 12010.

[0137] 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 a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether 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.

[0138] The foregoing has described an example of a mobile object control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the image capture unit 12031 of the above-described configuration. Specifically, the photodetection devices according to the above-described embodiments and their modifications (e.g., photodetection device 1) can be applied to the image capture unit 12031. By applying the technology according to the present disclosure to the image capture unit 12031, it is possible to obtain high-resolution captured images with little noise, thereby enabling high-precision control using the captured images in the mobile object control system.

[0139] While the present disclosure has been described above with reference to the embodiment, modifications 1 to 3, and application examples, the present disclosure is not limited to the above-described embodiment, etc., and various modifications are possible. For example, in the above-described embodiment, an example was shown in which the readout circuits that generate pixel signals based on the signal charges generated by the photoelectric conversion potentials of the photoelectric conversion units 12 of the red pixel Pr, the green pixel Pg, and the blue pixel Pb are provided on the circuit board 60, but the transistors that make up these readout circuits may be provided on the second surface 11S2 of the silicon substrate 11.

[0140] In the above-described embodiment, the chip on which the light receiving unit 10 and the light receiving unit 30 are formed and the chip on which the circuit board 60 for the readout circuit, logic circuit, etc. are formed are the same size, but this is not limiting. For example, the chip on which the circuit board 60 is formed may be larger than the chip on which the light receiving unit 10 and the light receiving unit 30 are formed.

[0141] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0142] The present disclosure may also be configured as follows. According to the present technology configured as follows, one or more wirings included in a first wiring layer provided between a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region and a second photoelectric conversion unit that photoelectrically converts wavelength components in the near-infrared region, which are stacked on each other, are formed using a material that transmits wavelength components in a wavelength region longer than the visible light region. This reduces the attenuation of light incident on the second photoelectric conversion unit. This makes it possible to improve image quality in both the visible light region and the near-infrared region. (1) A photodetector comprising: a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region; a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and photoelectrically converts wavelength components in the near-infrared region; and a first wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the first wiring layer including one or more wirings formed using a material that transmits wavelength components in a wavelength region longer than the visible light region, and used to read out charges generated by photoelectric conversion in the first photoelectric conversion unit. (2) The photodetector according to (1), wherein the one or more wirings are formed using polysilicon. (3) The photodetector according to (1) or (2), wherein the first photoelectric conversion unit is provided on a first semiconductor substrate having a first surface serving as a light incident surface and a second surface opposite the first surface. (4) The photodetector according to (3), wherein a plurality of pixels that photoelectrically convert any of wavelength components in a red band, a green band, and a blue band are arranged in an array on the first semiconductor substrate, and the first photoelectric conversion unit is embedded in the first semiconductor substrate for each of the plurality of pixels. (5) The photodetector according to (3) or (4), wherein the second photoelectric conversion unit is embedded in a second semiconductor substrate having a third surface and a fourth surface opposite the third surface, and the second semiconductor substrate is arranged such that the third surface faces the second surface of the first semiconductor substrate via the first wiring layer.(6) The photodetector according to (5), further comprising a circuit board disposed on the fourth surface side of the second semiconductor substrate and provided with one or more readout circuits that generate pixel signals based on charges generated by photoelectric conversion in the first photoelectric conversion unit and the second photoelectric conversion unit, and a logic circuit that processes the pixel signals. (7) The photodetector according to (5) or (6), further comprising a first circuit board provided with one or more readout circuits that generate pixel signals based on charges generated by photoelectric conversion in the first photoelectric conversion unit and the second photoelectric conversion unit, respectively, and a second circuit board provided with a logic circuit that processes the pixel signals, the first circuit board and the second circuit board being stacked in this order on the fourth surface side of the second semiconductor substrate. (8) The photodetector according to (6) or (7), further comprising one or more through-wirings penetrating between the third surface and the fourth surface of the second semiconductor substrate, wherein the one or more wiring layers and the one or more readout circuits are electrically connected to each other via the one or more through-wirings. (9) The photodetector according to (8), wherein the one or more through-wirings are provided around the second photoelectric conversion unit. (10) The photodetector according to any one of (1) to (9), wherein the second photoelectric conversion unit is provided for each of the plurality of first photoelectric conversion units. (11) The photodetector according to any one of (1) to (10), wherein the second photoelectric conversion unit is provided for each of the four first photoelectric conversion units arranged in 2 rows x 2 columns. (12) The photodetector according to (11), wherein, in a plan view, an intersection of the four first photoelectric conversion units arranged in 2 rows and 2 columns coincides with a center of the second photoelectric conversion unit. (13) The photodetector according to any one of (1) to (12), further comprising a pass filter between the first photoelectric conversion unit and the second photoelectric conversion unit, the pass filter selectively transmitting wavelength components in the near-infrared region. (14) The photodetector according to any one of (3) to (13), wherein the first semiconductor substrate is a silicon substrate.(15) The photodetector according to any one of (5) to (14), wherein the second semiconductor substrate is a substrate containing germanium, silicon germanium, indium gallium arsenide, or black silicon. (16) An electronic device including a photodetector having: a first photoelectric conversion unit that performs photoelectric conversion of wavelength components in a visible light region, a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and performs photoelectric conversion of wavelength components in a near-infrared region, and a first wiring layer that is provided between the first photoelectric conversion unit and the second photoelectric conversion unit and includes one or more wirings formed using a material that transmits wavelength components in a wavelength region longer than the visible light region, and that is used to read out charges generated by photoelectric conversion in the first photoelectric conversion unit. (17) A photodetection system comprising: a light source unit that emits near-infrared light; and a photodetector device that detects ambient light reflected from a subject and the near-infrared light, wherein the photodetector device has: a first photoelectric conversion unit that performs photoelectric conversion of wavelength components in the visible light region; a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and performs photoelectric conversion of wavelength components in the near-infrared region; and a first wiring layer that is provided between the first photoelectric conversion unit and the second photoelectric conversion unit and includes one or more wirings formed using a material that transmits wavelength components in a wavelength region longer than the visible light region, and that is used to read out charges generated by photoelectric conversion in the first photoelectric conversion unit.

[0143] This application claims priority to U.S. Provisional Patent Application No. 63 / 318,117, filed March 9, 2022, in the United States Patent and Trademark Office, the entire contents of which are incorporated herein by reference.

[0144] 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 photodetector comprising: a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region; a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and photoelectrically converts wavelength components in the near-infrared region; and a first wiring layer that is provided between the first and second photoelectric conversion units and includes one or more wirings formed from a material that transmits wavelength components in a region longer than the visible light region, and that is used to read out electric charges generated by photoelectric conversion in the first photoelectric conversion unit.

2. The photodetector device according to claim 1, wherein the one or more wirings are formed using polysilicon.

3. The photodetector device according to claim 1, wherein the first photoelectric conversion portion is provided on a first semiconductor substrate having a first surface that serves as a light incident surface and a second surface opposite to the first surface.

4. The photodetector device according to claim 3, wherein a plurality of pixels that photoelectrically convert any of wavelength components in the red band, wavelength components in the green band, and wavelength components in the blue band are arranged in an array on the first semiconductor substrate, and the first photoelectric conversion unit is embedded in the first semiconductor substrate for each of the plurality of pixels.

5. The photodetector device described in claim 3, wherein the second photoelectric conversion section is embedded in a second semiconductor substrate having a third surface and a fourth surface opposite to the third surface, and the second semiconductor substrate is arranged so that the third surface faces the second surface of the first semiconductor substrate via the first wiring layer.

6. The photodetector device according to claim 5, further comprising a circuit board disposed on the fourth surface side of the second semiconductor substrate and provided with one or more readout circuits that generate pixel signals based on charges generated by photoelectric conversion in the first photoelectric conversion unit and the second photoelectric conversion unit, and a logic circuit that processes the pixel signals.

7. The photodetector device according to claim 5, further comprising a first circuit board provided with one or more readout circuits that generate pixel signals based on charges generated by photoelectric conversion in each of the first photoelectric conversion unit and the second photoelectric conversion unit, and a second circuit board provided with a logic circuit that processes the pixel signals, wherein the first circuit board and the second circuit board are stacked in this order on the fourth surface side of the second semiconductor substrate.

8. The photodetector device described in claim 6, further comprising one or more through-wirings penetrating between the third surface and the fourth surface of the second semiconductor substrate, wherein the one or more wiring layers and the one or more readout circuits are electrically connected to each other via the one or more through-wirings.

9. The photodetector according to claim 8, wherein the one or more through-wirings are provided around the second photoelectric conversion portion.

10. The photodetector according to claim 1, wherein the second photoelectric conversion section is provided for each of the plurality of first photoelectric conversion sections.

11. The photodetector according to claim 1, wherein the second photoelectric conversion units are provided one for each of the four first photoelectric conversion units arranged in two rows and two columns.

12. The photodetector device according to claim 11, wherein, in a plan view, the intersection of the four first photoelectric conversion units arranged in two rows and two columns coincides with the center of the second photoelectric conversion unit.

13. The photodetector according to claim 1, further comprising a pass filter between the first photoelectric conversion section and the second photoelectric conversion section, which selectively transmits wavelength components in the near-infrared region.

14. The photodetector device of claim 3, wherein said first semiconductor substrate is a silicon substrate.

15. The photodetector device of claim 5, wherein the second semiconductor substrate is a substrate containing germanium, silicon germanium, indium gallium arsenide, or black silicon.

16. An electronic device equipped with a photodetector having: a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region; a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and photoelectrically converts wavelength components in the near-infrared region; and a first wiring layer that is provided between the first photoelectric conversion unit and the second photoelectric conversion unit and includes one or more wirings formed using a material that transmits wavelength components in a region longer than the visible light region, and that is used to read out charges generated by photoelectric conversion in the first photoelectric conversion unit.

17. A photodetection system comprising: a light source unit that emits near-infrared light; and a photodetector device that detects ambient light reflected from a subject and the near-infrared light, wherein the photodetector device has: a first photoelectric conversion unit that photoelectrically converts wavelength components in the visible light region; a second photoelectric conversion unit that is stacked on the first photoelectric conversion unit and photoelectrically converts wavelength components in the near-infrared region; and a first wiring layer that is provided between the first photoelectric conversion unit and the second photoelectric conversion unit and includes one or more wirings formed from a material that transmits wavelength components in a wavelength region longer than the visible light region, and that is used to read out charges generated by photoelectric conversion in the first photoelectric conversion unit.

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