Photodetection device and electronic equipment

Abstract

A photodetection device according to an embodiment of the present disclosure comprises: a first photoelectric conversion unit; a second photoelectric conversion unit that is disposed on the light incident side of the first photoelectric conversion unit; and a multilayer wiring layer that is provided between the first photoelectric conversion unit and the second photoelectric conversion unit and that includes a wiring layer, at least a portion of which is formed by using a conductive material that is transparent with respect to wavelengths of at least portions of the visible light band and the near-infrared band.

Description

Photodetector and electronic equipment

[0001] The present disclosure relates to a photodetector and an electronic device in which a plurality of photoelectric conversion units are stacked.

[0002] For example, Patent Document 1 discloses a surface-type CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0003] International Publication No. 2014 / 017314

[0004] In surface-type CMOS image sensors, metal wiring is present on the photodiode (PD) located below, which causes a loss of light incident on the PD located below, resulting in a decrease in sensitivity. Therefore, in photodetector devices in which multiple photoelectric conversion units are stacked, there is a need to improve the sensitivity of the lower photoelectric conversion units.

[0005] It is desirable to provide a photodetector and electronic equipment that can improve the sensitivity of the lower photoelectric conversion section in a configuration in which a plurality of photoelectric conversion sections are stacked.

[0006] An optical detection device according to one embodiment of the present disclosure includes a first photoelectric conversion unit, a second photoelectric conversion unit arranged on the light incident side of the first photoelectric conversion unit, and a multilayer wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the multilayer wiring layer including a wiring layer at least a portion of which is formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band.

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

[0008] In a photodetector according to an embodiment of the present disclosure and an electronic device according to an embodiment, a multilayer wiring layer is provided between a first photoelectric conversion unit and a second photoelectric conversion unit that are stacked in order toward a light incident side. The multilayer wiring layer includes a wiring layer formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band. This reduces loss of light incident on the first photoelectric conversion unit disposed below the multilayer wiring layer.

[0009] FIG. 1 is a cross-sectional view illustrating an example of a photodetector according to an embodiment of the present disclosure. FIG. 2 is a plan view schematically illustrating an example of a layout of transistors constituting readout circuits of the first photoelectric conversion unit and the second photoelectric conversion unit of the photodetector shown in FIG. 1. FIG. 3 is an equivalent circuit diagram of the photodetector shown in FIG. 1. FIG. 4A is a cross-sectional view illustrating a method for manufacturing the photodetector shown in FIG. 1. FIG. 4B is a cross-sectional view illustrating a step subsequent to FIG. 4A. FIG. 4C is a cross-sectional view illustrating a step subsequent to FIG. 4B. FIG. 4D is a cross-sectional view illustrating a step subsequent to FIG. 4C. FIG. 4E is a cross-sectional view illustrating a step subsequent to FIG. 4D. FIG. 4F is a cross-sectional view illustrating a step subsequent to FIG. 4E. FIG. 4G is a cross-sectional view illustrating a step subsequent to FIG. 4F. FIG. 4H is a cross-sectional view illustrating a step subsequent to FIG. 4G. FIG. 4I is a cross-sectional view illustrating a step subsequent to FIG. 4H. FIG. 5 is a cross-sectional view illustrating an example of a photodetector according to Modification 1 of the present disclosure. FIG. 6 is a cross-sectional view illustrating an example of a photodetector according to Modification 1 of the present disclosure. FIG. 7 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 2 of the present disclosure. FIG. 8 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 2 of the present disclosure. FIG. 9 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 2 of the present disclosure. FIG. 10 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 3 of the present disclosure. FIG. 11 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 4 of the present disclosure. FIG. 12 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 5 of the present disclosure. FIG. 13 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 5 of the present disclosure. FIG. 14 is a cross-sectional configuration diagram showing an example of a photodetector according to Modification 5 of the present disclosure. FIG. 15 is a block diagram showing the overall configuration of the photodetector shown in FIG. 1 etc. FIG. 16 is a block diagram showing an example of the configuration of an electronic device using the photodetector shown in FIG. 1A. FIG. 17A is a schematic diagram showing an example of the overall configuration of a photodetection system using the photodetector shown in FIG. 1A. FIG. 17B is a diagram showing an example of the circuit configuration of the photodetection system shown in FIG. 17A. Fig. 18 is a diagram showing an example of a schematic configuration of an endoscopic surgery system, Fig. 19 is a block diagram showing an example of a functional configuration of a camera head and a CCU, and Fig. 20 is a block diagram showing an example of a schematic configuration of a vehicle control system.Fig. 21 is an explanatory diagram showing an example of the installation positions of the vehicle outside information detection unit and the imaging unit. Fig. 22 is a cross-sectional configuration diagram showing an example of a light detection device as another modified example of the present disclosure.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is one 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 of a photodetector in which a part of a multilayer wiring layer provided between a first photoelectric conversion unit and a second photoelectric conversion unit is formed using a light-transmitting conductive material) 2. Modifications 2-1. Modification 1 (another example of the configuration of the photodetector) 2-2. Modification 2 (another example of the configuration of the photodetector) 2-3. Modification 3 (another example of the configuration of the photodetector) 2-4. Modification 4 (another example of the configuration of the photodetector) 2-5. Modification 5 (another example of the configuration of the photodetector) 3. Application Examples 4. Application Examples

[0011] 1 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1) according to an embodiment of the present disclosure. The photodetector 1 is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0012] The photodetector 1 has a multilayer wiring layer 30 between a first photoelectric conversion unit 10 and a second photoelectric conversion unit 20 arranged on the light incident side S1 of the first photoelectric conversion unit 10. The multilayer wiring layer 30 includes a first wiring layer 311 electrically connected to the first photoelectric conversion unit 10, a second wiring layer 312 electrically connected to the first wiring layer 311, and a third wiring layer 313 electrically connected to the second wiring layer 312 and the second photoelectric conversion unit 20. In the photodetector 1 of this embodiment, at least one of the first wiring layer 311, the second wiring layer 312, and the third wiring layer 313 is formed using a conductive material that is transparent to wavelengths in at least a part of the visible light band and the near-infrared band.

[0013] Here, the first photoelectric conversion section 10 corresponds to a specific example of a "first photoelectric conversion section" according to an embodiment of the present disclosure. The second photoelectric conversion section 20 corresponds to a specific example of a "second photoelectric conversion section" according to an embodiment of the present disclosure. The multilayer wiring layer 30 corresponds to a specific example of a "multilayer wiring layer" according to an embodiment of the present disclosure.

[0014] [Configuration of Photodetector] The configuration of the photodetector 1 of this embodiment will be described with reference to Figures 1 and 2. Figure 2 schematically shows an example of the layout of transistors constituting the readout circuits (readout circuits 13 and 14) of the first photoelectric conversion unit 10 and the second photoelectric conversion unit 20 of the photodetector 1 shown in Figure 1. In Figures 1 and 2, the stacking direction of the first photoelectric conversion unit 10 and the second photoelectric conversion unit 20 is defined as the Z-axis direction, and the plane directions parallel to the stacking plane perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to one another.

[0015] The photodetector 1 is a so-called vertical spectroscopic photodetector in which a first photoelectric conversion unit 10 and a second photoelectric conversion unit 20 are stacked in the vertical direction (Z-axis direction). The second photoelectric conversion unit 20 is disposed on a light incident side S1 of the first photoelectric conversion unit 10, and a multilayer wiring layer 30 is provided between the first photoelectric conversion unit 10 and the second photoelectric conversion unit 20. A logic substrate 50 is disposed on the side opposite the light incident side S1 of the first photoelectric conversion unit 10. On the light incident side S1 of the second photoelectric conversion unit 20, for example, a protective layer 41, a low-refractive index layer 42, a color filter layer 43, and an on-chip lens layer 44 are stacked in the Z-axis direction in this order from the second photoelectric conversion unit 20 side.

[0016] (First Photoelectric Conversion Unit) The first photoelectric conversion unit 10 is, for example, an indirect TOF (hereinafter referred to as iTOF) sensor that acquires a distance image (distance information) by optical time-of-flight (TOF). The first photoelectric conversion unit 10 includes, for example, a semiconductor substrate 11 having a pair of opposing surfaces (a first surface 11S1 and a second surface 11S2), a photoelectric conversion region 12, floating diffusions FD1 and FD2, readout circuits 13 and 14, VSS contact regions 15, 17, and 18, and VDD contact regions 15 and 19. The first photoelectric conversion section 10 has, for example, a surface-illuminated structure, and the floating diffusions FD1 and FD2, the readout circuits 13 and 14, the VSS contact regions 15, 17, and 18, and the VDD contact regions 15 and 19 are provided on a first surface 11S1 of the semiconductor substrate 11 facing the light incident side S1.

[0017] The semiconductor substrate 11 is, for example, an n-type silicon (Si) substrate, and has a p-well in a predetermined region.

[0018] The photoelectric conversion region 12 is a photoelectric conversion element configured by, for example, a PIN (Positive Intrinsic Negative) type photodiode (PD), and includes a pn junction formed in a predetermined region of the semiconductor substrate 11. The photoelectric conversion region 12 detects and receives light from the subject, for example, wavelengths in the near-infrared band, and generates and accumulates electric charges according to the amount of received light through photoelectric conversion.

[0019] As described above, the first surface 11S1 of the semiconductor substrate 11 is provided with, for example, floating diffusions FD1 and FD2, readout circuits 13 and 14, VSS contact regions 15, 17, and 18, and VDD contact regions 15 and 19. The floating diffusion FD1 is a floating diffusion region that converts charges transferred from the photoelectric conversion region 12 into electronic signals (e.g., voltage signals) and outputs the signals. The readout circuit 13 is connected to the floating diffusion FD1. The floating diffusion FD2 is a floating diffusion region that converts charges transferred from a photoelectric conversion layer 23 (described later) into electrical signals (e.g., voltage signals) and outputs the electrical signals. The readout circuit 14 is connected to the floating diffusion FD2.

[0020] FIG. 3 is an equivalent circuit diagram of the photodetector 1 shown in FIG.

[0021] The read circuit 13 includes a transfer transistor TR1, an amplifier transistor (modulation element) AMP1, a reset transistor RST1, and a selection transistor SEL1.

[0022] The transfer transistor TR1 is connected between the photoelectric conversion region 12 and the floating diffusion FD1. When a drive signal is applied to the gate electrode of the transfer transistor TR1 and the transfer transistor TR1 is activated, the transfer gate of the transfer transistor TR1 is turned on. As a result, signal charges converted in the photoelectric conversion region 12 are transferred to the floating diffusion FD1 via the transfer transistor TR1. The transfer transistor TR1 is, for example, configured as a vertical transistor. The transfer transistor TR1 is connected to a transfer gate line TG1.

[0023] The floating diffusion FD1 is connected between the transfer transistor TR1 and the amplifier transistor AMP1. The floating diffusion FD1 converts the signal charges transferred by the transfer transistor TR1 into a voltage signal and outputs the voltage signal to the amplifier transistor AMP1.

[0024] The reset transistor RST1 is connected between the floating diffusion FD1 and the power supply line VDD. When a drive signal is applied to the gate electrode of the reset transistor RST1 and the reset transistor RST1 is activated, the reset gate of the reset transistor RST1 is turned on. As a result, the potential of the floating diffusion FD1 is reset to the power supply level.

[0025] The amplifier transistor AMP1 has a gate electrode connected to the floating diffusion FD1 and a drain electrode connected to the power supply line VDD. The amplifier transistor AMP1 serves as the input of a readout circuit for the voltage signal held by the floating diffusion FD1, a so-called source follower circuit. That is, the amplifier transistor AMP1 has its source electrode connected to a signal line (data output line) VSL1 via the select transistor SEL1, thereby forming a source follower circuit together with a constant current source connected to one end of the signal line VSL1. The gate electrode of the amplifier transistor AMP1 is connected to the other source / drain region (floating diffusion FD1) of the reset transistor RST1.

[0026] Each selection transistor SEL1 is connected between the source electrode of the amplifier transistor AMP1 and a signal line VSL1. Specifically, the gate electrode of the selection transistor SEL1 is connected to the selection line SELL1. When a drive signal is applied to each gate electrode of the selection transistor SEL1 and the selection transistor SEL1 is activated, the selection transistor SEL1 is rendered conductive and the pixel P is rendered selected. As a result, a readout signal (pixel signal) output from the amplifier transistor AMP1 is output to the signal line VSL1 via the selection transistor SEL1.

[0027] In the photodetector 1, a near-infrared light pulse is irradiated onto a subject, and the light pulse reflected from the subject is received by the photoelectric conversion region 12 of the first photoelectric conversion unit 10. In the photoelectric conversion region 12, a plurality of electric charges are generated in response to the incident near-infrared light pulse. The plurality of electric charges generated in the photoelectric conversion region 12 are alternately distributed to the floating diffusions FD1 connected to the pair of transfer transistors TR1, for example, by alternately supplying drive signals to the pair of transfer transistors TR1 for equal periods of time. By changing the shutter phase of the drive signal applied to the transfer transistors TR1 relative to the irradiated light pulse, the amount of electric charge accumulated in one floating diffusion FD1 and the amount of electric charge accumulated in the other floating diffusion FD1 become phase-modulated values. By demodulating these values, the round-trip time of the light pulse can be estimated, thereby determining the distance between the photodetector 1 and the subject.

[0028] The read circuit 14 includes an amplifier transistor AMP2, a reset transistor RST2, and a selection transistor SEL2.

[0029] The floating diffusion FD2 is connected between the read electrode 21A and the amplifier transistor AMP2. The floating diffusion FD2 converts the signal charges transferred by the read electrode 21A into a voltage signal and outputs the voltage signal to the amplifier transistor AMP2.

[0030] The reset transistor RST2 is connected between the floating diffusion FD2 and the power supply line VDD. The gate electrode of the reset transistor RST2 is connected to a reset line RSTL2, and a drive signal is applied via this reset line RSTL2. When the reset transistor RST2 is activated, the reset gate of the reset transistor RST2 is rendered conductive. As a result, the potential of the floating diffusion FD2 is reset to the power supply level.

[0031] The amplifier transistor AMP2 is a modulation element that modulates the amount of charge generated in the second photoelectric conversion unit 20 into a voltage. The amplifier transistor AMP2 has a gate electrode connected to the floating diffusion FD2 and a drain electrode connected to the power supply line VDD. The source electrode of the amplifier transistor AMP2 is connected to a signal line (data output line) VSL2 via a selection transistor SEL2.

[0032] The selection transistor SEL2 is connected between the source electrode of the amplifier transistor AMP2 and a signal line (data output line) VSL2. The gate electrode of the selection transistor SEL2 is connected to the selection line SELL2, and a drive signal is applied via this selection line SELL2. When the selection transistor SEL2 is in an active state, the selection transistor SEL2 is turned on, and the pixel P2 is turned to a selected state. As a result, a readout signal (pixel signal) output from the amplifier transistor AMP2 is output to the signal line VSL2 via the selection transistor SEL2.

[0033] The read circuit 14 may further include an FD conversion gain switching transistor FDG. The FD conversion gain switching transistor FDG is arranged between the floating diffusion FD2 and the reset transistor RST2. That is, for example, the source of the FD conversion gain switching transistor FDG is electrically connected to the floating diffusion FD2, and the drain of the FD conversion gain switching transistor FDG is electrically connected to the source of the reset transistor RST2.

[0034] The FD conversion gain switching transistor FDG is used to change the gain of charge-to-voltage conversion in the floating diffusion FD2. Generally, pixel signals are small when shooting in dark locations. Based on Q = CV, when performing charge-to-voltage conversion, if the capacitance (FD capacitance C) of the floating diffusion FD2 is large, V when converted to a voltage by the amplifier transistor AMP2 will be small. On the other hand, in bright locations, pixel signals are large, so if the FD capacitance C is not large, the floating diffusion FD2 will not be able to fully absorb the charge from the photodiode PD. Furthermore, the FD capacitance C must be large so that V when converted to a voltage by the amplifier transistor AMP2 does not become too large (in other words, so that it becomes small). Taking these factors into consideration, when the FD conversion gain switching transistor FDG is turned on, the gate capacitance of the FD conversion gain switching transistor FDG increases, increasing the overall FD capacitance C. On the other hand, when the FD conversion gain switching transistor FDG is turned off, the overall FD capacitance C decreases. In this way, by switching the FD conversion gain switching transistor FDG on and off, the FD capacitance C can be made variable, and the conversion efficiency can be switched.

[0035] The reset lines RSTL1 and RSTL2, the selection lines SELL1 and SELL2, and the transfer gate line TG1 are each connected to a vertical drive circuit 111 that constitutes a drive circuit. The signal lines (data output lines) VSL1 and VSL2 are connected to a column signal processing circuit 112 that constitutes a drive circuit (see FIG. 15 for all of them).

[0036] (Second Photoelectric Conversion Unit) The second photoelectric conversion unit 20 includes, for example, a lower electrode 21, an insulating layer (interlayer insulating layer 31), a semiconductor layer 22, a photoelectric conversion layer 23, and an upper electrode 24, which are stacked in order from the position closest to the first photoelectric conversion unit 10. The lower electrode 21 includes, for example, a readout electrode 21A, a charge storage electrode 21B, and a shield electrode 21C, which are spaced apart from one another. The readout electrode 21A, the charge storage electrode 21B, and the shield electrode 21C are provided, for example, on the same layer. The readout electrode 21A is electrically connected to the semiconductor layer 22 through an opening H provided in the interlayer insulating layer 31 and is connected to the floating diffusion FD2 via wiring provided in the multilayer wiring layer 30. The charge storage electrode 21B faces the semiconductor layer 22 via the interlayer insulating layer 31. The charge storage electrode 21B, together with the interlayer insulating layer 31 and the semiconductor layer 22, forms a type of capacitor, and accumulates charges generated in the photoelectric conversion layer 23 in a portion of the semiconductor layer 22, for example, a region of the semiconductor layer 22 corresponding to the charge storage electrode 21B via the interlayer insulating layer 31. In the second photoelectric conversion unit 20, for example, one charge storage electrode 21B is provided corresponding to each color filter (red filter 43R, green filter 32G, and blue filter 43B) of the color filter layer 43 and each on-chip lens 44L. The charge storage electrode 21B is connected to, for example, the vertical drive circuit 111 (see FIG. 15 ). A predetermined potential is applied to the shield electrode 21C, electrically isolating adjacent unit pixels P2.

[0037] The semiconductor layer 22, the photoelectric conversion layer 23, and the upper electrode 24 may be provided in common to some of the unit pixels P2 in the pixel section 100A, or may be provided in common to all of the unit pixels P in the pixel section 100A. The same applies to the modified examples described later in this embodiment.

[0038] Further, other organic layers may be provided between the semiconductor layer 22 and the photoelectric conversion layer 23 and between the photoelectric conversion layer 23 and the upper electrode 24 .

[0039] The lower electrode 21 and the upper electrode 24 are made of a conductive film having optical transparency. Examples of the conductive film having optical transparency include ITO (indium tin oxide). However, in addition to ITO, the constituent materials of the lower electrode 21 and the upper electrode 24 may also include tin oxide (SnOx)-based materials with dopants added thereto, and zinc oxide-based materials obtained by adding dopants to zinc oxide (ZnO). Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, and indium zinc oxide (IZO) with indium (In) added. The constituent materials of the lower electrode 21 and the upper electrode 24 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ The lower electrode 21 and the upper electrode 24 may further include spinel oxides and YbFe ２ O ４ Oxides having such a structure may also be used.

[0040] The material constituting the semiconductor layer 22 preferably has a large band gap (for example, a band gap of 3.0 eV or more) and a higher mobility than the material constituting the photoelectric conversion layer 23. Specific examples of such a material include oxide semiconductor materials such as IGZO, transition metal dichalcogenides, silicon carbide, diamond, graphene, and carbon nanotubes, as well as organic semiconductor materials such as condensed polycyclic hydrocarbon compounds and condensed heterocyclic compounds.

[0041] The photoelectric conversion layer 23 converts light energy into electrical energy and is formed, for example, by including two or more organic materials that function as p-type and n-type semiconductors. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 23 has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction interface formed by mixing a p-type semiconductor and an n-type semiconductor, and excitons generated upon light absorption separate into electrons and holes at this p / n junction interface.

[0042] In addition to the p-type and n-type semiconductors, the photoelectric conversion layer 23 may further include three types of so-called dye materials that photoelectrically convert light in a predetermined wavelength band while transmitting light in other wavelength bands. The p-type semiconductor, n-type semiconductor, and dye material preferably have different maximum absorption wavelengths. This allows absorption of light in a wide range of wavelengths in the visible light region.

[0043] The photoelectric conversion layer 23 can be formed by, for example, mixing the various organic semiconductor materials described above and using a spin coating technique. Alternatively, the photoelectric conversion layer 23 may be formed by, for example, vacuum deposition or printing.

[0044] The photoelectric conversion layer 23 may be formed using semiconductor quantum dots in addition to an organic material.

[0045] As described above, the second photoelectric conversion unit 20 detects some or all of the wavelengths in the visible light range. It is also preferable that the second photoelectric conversion unit 20 does not have sensitivity to the infrared light range.

[0046] In the second photoelectric conversion section 20, light incident from the upper electrode 24 side is absorbed by the photoelectric conversion layer 23. The resulting excitons (electron-hole pairs) migrate to the interface between the electron donor and electron acceptor constituting the photoelectric conversion layer 23, where they undergo exciton dissociation, i.e., dissociation into electrons and holes. The generated charges, i.e., electrons and holes, migrate to the upper electrode 24 or the semiconductor layer 22 due to diffusion caused by the difference in charge concentration or an internal electric field caused by the potential difference between the upper electrode 24 and the charge storage electrode 21B, and are detected as photocurrent. For example, the readout electrode 21A is set to a positive potential and the upper electrode 24 is set to a negative potential. In this case, holes generated by photoelectric conversion in the photoelectric conversion layer 23 migrate to the upper electrode 24. Electrons generated by photoelectric conversion in the photoelectric conversion layer 23 are attracted to the charge storage electrode 21B and accumulated in a portion of the semiconductor layer 22, for example, a region of the semiconductor layer 22 corresponding to the charge storage electrode 21B via the interlayer insulating layer 31.

[0047] Charges (e.g., electrons) stored in the region of the semiconductor layer 22 corresponding to the charge storage electrode 21B via the interlayer insulating layer 31 are read out as follows. Specifically, a potential V2 is applied to the read electrode 21A, and a potential V1 is applied to the charge storage electrode 21B. Here, the potential V2 is made higher than the potential V1 (V1<V2). In this way, the electrons stored in the region of the semiconductor layer 22 corresponding to the charge storage electrode 21B are transferred to the read electrode 21A.

[0048] By providing the semiconductor layer 22 below the photoelectric conversion layer 23 and storing charges (e.g., electrons) in the region of the semiconductor layer 22 corresponding to the charge storage electrode 21B via the interlayer insulating layer 31, the following effects can be obtained. That is, compared to storing charges (e.g., electrons) in the photoelectric conversion layer 23 without providing the semiconductor layer 22, recombination of holes and electrons during charge storage is prevented, the transfer efficiency of the stored charges (e.g., electrons) to the readout electrode 21A can be increased, and the generation of dark current can be suppressed. Although the above description illustrates the case where electrons are read out, holes may also be read out. When holes are read out, the potential in the above description is described as the potential sensed by the holes.

[0049] (Multilayer Wiring Layer) The multilayer wiring layer 30 has a plurality of wiring layers stacked within the interlayer insulating layer 31 with the interlayer insulating layer 31 between them. Specifically, the multilayer wiring layer 30 has a gate wiring layer 32 including gate electrodes of various transistors that constitute the readout circuits 13, 14 of the first photoelectric conversion unit 10 and the second photoelectric conversion unit 20 described above, a wiring layer M1 including a transfer gate line TG1, and wiring layers M2-1 to M2-m and M3-1 to M3-m including reset lines RSTL1, RSTL2, select lines SELL1, SELL2, signal lines VSL1, VSL2, etc. In addition, the multilayer wiring layer 30 includes a via V1 connected to the floating diffusions FD1 and FD2, the VSS contact regions 15, 17, and 18, and the VDD contact regions 15 and 19, a via V2 connected to a gate wiring layer 32 including various gate electrodes, and vias V3, V4, and V5 connecting the above wirings.

[0050] In this embodiment, at least a portion of the wiring including the vias V1, V2, V3, V4, and V5 provided within the interlayer insulating layer 31 is formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and near-infrared band.

[0051] For example, among the above wirings, as shown in FIG. 1, the gate wiring layer 32 provided near the first surface 11S1 of the first photoelectric conversion unit 10 and provided above the photoelectric conversion region 12, the wiring layer M1 extending to above the photoelectric conversion region 12, and the vias V1 and V2 connecting these are included in the first wiring layer 311, and for example, the wiring layers M2-1 to M2-m and a plurality of pad portions 33 and When the vias V3, V4, and V5 connecting these are defined as the second wiring layer 312, and the wiring layers M3-1 to M3-m provided above the photoelectric conversion region 12 on the second photoelectric conversion unit 20 side, including the lower electrode 21 of the second photoelectric conversion unit 20, are defined as the third wiring layer 313, the first wiring layer 311 and the third wiring layer 313, which are so-called local wiring, are formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and near-infrared band. The second wiring layer 312, which is so-called global wiring and desirably has low resistance, is formed using a metal material with a lower electrical resistivity than the above conductive material. This reduces the loss of light incident on the first photoelectric conversion unit 10. Furthermore, since it is not necessary to design the first photoelectric conversion unit 10 while taking into account the effect of light loss, the degree of freedom in the arrangement and wiring layout of the transistors constituting the readout circuits 13 and 14 is improved.

[0052] In addition, among the first wiring layer 311 and the third wiring layer 313, vias that are desirable to have lower resistance (for example, via V2 connecting the amplifier transistor AMP1 and the wiring layer M1 in Figure 2) and vias provided between unit pixels P1 (for example, via V1 connected to the VSS contact regions 15, 17, and 18 and the VDD contact regions 16 and 19 in Figure 2) may be formed using a metal material.

[0053] Examples of conductive materials that are transparent to wavelengths in at least a portion of the visible light band and near-infrared band include polysilicon (Poly-Si), ITO, IZO, ZnO, etc. Examples of metal materials include copper (Cu), aluminum (Al), ruthenium (Ru), cobalt (Co), rhodium (Rh), molybdenum (Mo), etc.

[0054] The first wiring layer 311, the second wiring layer 312, and the third wiring layer 313 have different electrical resistivities. For example, when the electrical resistivity of the first wiring layer is R1, the electrical resistivity of the second wiring layer is R2, and the electrical resistivity of the third wiring layer is R3, the relationship is R2<R3<R1.

[0055] The interlayer insulating layer 31 is composed of a single layer film made of one type of inorganic insulating material, such as silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiON), or a laminate film made of two or more types of these. Furthermore, the material constituting the interlayer insulating layer 31 may be an organic insulating material, such as polymethyl methacrylate (PMMA), polyvinylphenol (PVP), polyvinyl alcohol (PVA), polyimide, polycarbonate (PC), polyethylene terephthalate (PET), polystyrene, N-2(aminoethyl)3-aminopropyltrimethoxysilane (AEAPTMS), 3-mercaptopropyltrimethoxysilane (MPTMS), tetraethoxysilane (TEOS), or octadecyltrichlorosilane (OTS).

[0056] As described above, for example, a protective layer 41, a low-refractive index layer 42, a color filter layer 43, and an on-chip lens layer 44 are stacked in the Z-axis direction on the light incident side S1 of the second photoelectric conversion unit 20 in this order from the second photoelectric conversion unit 20 side. The protective layer 41 and the low-refractive index layer 42 may each be provided in common to a plurality of unit pixels P2.

[0057] The protective layer 41 has a configuration in which transparent insulating films such as aluminum oxide (AlO) are laminated.

[0058] The low refractive index layer 42 suppresses crosstalk to adjacent unit pixels P2 and also serves as a separation wall that separates the color filter layer 43 into individual pixels.

[0059] The color filter layer 43 includes, for example, a red filter 43R that mainly transmits red light, a green filter 43G that mainly transmits green light, and a blue filter 43B that mainly transmits blue light, and each of these filters is provided for each unit pixel P2. The unit pixel P2 provided with the red filter 43R, green filter 43G, or blue filter 43B receives light of the opposite color, thereby obtaining a full-color visible light image.

[0060] The on-chip lens layer 44 has an on-chip lens 44L provided for each unit pixel P2. The surface of the on-chip lens layer 44 may be covered with an anti-reflection film.

[0061] [Method for Manufacturing Photodetector] The photodetector 1 can be manufactured, for example, as follows.

[0062] First, as shown in FIG. 4A, the photoelectric conversion region 12 of the semiconductor substrate 11 is formed by burying. Next, as shown in FIG. 4A, the transistors constituting the readout circuits 13 and 14 are formed, and an interlayer insulating layer 31 is deposited.

[0063] Subsequently, as shown in FIG. 4B, openings penetrating the interlayer insulating layer 31 are formed at predetermined positions using, for example, photolithography and etching.

[0064] Next, as shown in FIG. 4C , a conductive film that is transparent to wavelengths in at least a portion of the visible light band and near-infrared band that constitutes the first wiring layer 311 is formed, for example, by sputtering, and the opening that penetrates the interlayer insulating layer 31 is filled.

[0065] 4D, the conductive film formed on the interlayer insulating layer 31 is removed by, for example, chemical mechanical polishing (CMP), thereby forming vias V1 and V2.

[0066] 4E, a conductive film that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band is formed, and then the conductive film is processed using photolithography and etching to form a wiring layer M1. Subsequently, as shown in FIG. 4E, an interlayer insulating layer 31 is further formed.

[0067] Next, as shown in FIG. 4F, the interlayer insulating layer 31 formed on the wiring layer M1 is removed by, for example, CMP, to flatten the surface.

[0068] 4G, wiring layers M2-1 to M2-m are formed in order, and then an interlayer insulating layer 31 is further formed to embed the wiring layers M2-1 to M2-m. Next, as shown in FIG. 4G, the surface is planarized by, for example, CMP, and then an interlayer insulating layer 31 is further formed, and openings are formed at predetermined positions using, for example, photolithography and etching. Next, as shown in FIG. 4G, a copper film, for example, that forms the pad portion 33 is formed by, for example, sputtering, to embed the openings.

[0069] 4H, the copper film formed on the interlayer insulating layer 31 is removed by, for example, CMP, thereby forming the pad portion 33.

[0070] 4I, similarly, wiring layers M3-1 to M2-n and lower electrode 21 are sequentially formed, and then an interlayer insulating layer 31 is further deposited to embed wiring layers M3-1 to M2-n. Next, the surface is planarized by, for example, CMP, and an opening H is formed. Then, a semiconductor layer 22, a photoelectric conversion layer 23, and an upper electrode 24 are sequentially deposited to form the second photoelectric conversion unit 20.

[0071] Thereafter, the logic substrate 50 is bonded to the second surface 11S2 side of the semiconductor substrate 11, and the protective layer 41, the low refractive index layer 42, and the color filter layer 43 are formed in this order on the light incident side S1 of the second photoelectric conversion unit 20, and finally the on-chip lens layer 44 is bonded. In this way, the photodetector 1 shown in FIG. 1 is completed.

[0072] [Functions and Effects] In the photodetector 1 of this embodiment, a portion of the wiring layer included in the multilayer wiring layer 30 provided between the first photoelectric conversion section 10 and the second photoelectric conversion section 20, which are stacked in order toward the light incident side, is formed using a conductive material that is transparent to wavelengths in at least part of the visible light band and the near-infrared band. This reduces the loss of light incident on the first photoelectric conversion section disposed below the multilayer wiring layer. This is described below.

[0073] As described above, for example, in a surface-type CMOS image sensor in which an organic photodiode is stacked on a silicon photodiode, metal wiring is disposed between the silicon photodiode and the organic photodiode. Such surface-type CMOS image sensors have a problem in that sensitivity is reduced due to loss of light incident on the silicon photodiode disposed below the metal wiring. Furthermore, because pixel transistors using metal wiring are present, attempts to miniaturize pixels result in metal wiring and vias connected to the pixel transistors overlapping the silicon photodiode, which also results in a problem in that sensitivity is reduced due to loss of light incident on the silicon photodiode.

[0074] In contrast to this, in this embodiment, as described above, a portion of the wiring layer included in the multilayer wiring layer 30 provided between the first photoelectric conversion section 10 and the second photoelectric conversion section 20 stacked in order toward the light incident side is formed using a conductive material that is transparent to wavelengths in at least some of the visible light band and near-infrared band. Specifically, among the multiple wiring layers formed within the multilayer wiring layer 30, the local wiring, i.e., the first wiring layer 311 including the wiring layer M1 extending above the photoelectric conversion region 12 and the vias V1 and V2 connecting them, and the lower electrode 21 of the second photoelectric conversion unit 20, as well as the third wiring layer 313 including wiring layers M3-1 to M3-m provided above the photoelectric conversion region 12 on the second photoelectric conversion unit 20 side, are formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band. The global wiring, i.e., the second wiring layer 312 including the wiring layers M2-1 to M2-m provided between adjacent unit pixels P1, the multiple pad portions 33 and 34, and the vias V3, V4, and V5 connecting them, are formed using a metal material with a lower electrical resistivity than the conductive material. This reduces the loss of light incident on the first photoelectric conversion unit 10.

[0075] As described above, in the photodetector 1 of this embodiment, it is possible to improve the sensitivity of the first photoelectric conversion section 10 disposed below the multilayer wiring layer 30 .

[0076] Furthermore, in the photodetector device 1 of this embodiment, there is no need for a design that takes into account the effect of light loss on the first photoelectric conversion unit 10 arranged below the multilayer wiring layer 30, which makes it possible to improve the freedom of arrangement and wiring layout of each transistor that constitutes the readout circuits 13 and 14.

[0077] Next, modified examples 1 to 5 and application examples of the present disclosure will be described. Note that components corresponding to those in the above embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0078] 5 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1A) according to Modification 1 of the present disclosure. FIG. 6 is a schematic diagram illustrating another example of a cross-sectional configuration of the photodetector 1A according to Modification 1 of the present disclosure. Like the photodetector 1 of the above embodiment, the photodetector 1A is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0079] 5, the photodetector 1A differs from the photodetector 1 of the above embodiment in that an IR pass filter 35 that selectively transmits, for example, wavelengths in the near-infrared region is provided above the photoelectric conversion region 12. The IR pass filter 35 is disposed, for example, in the second wiring layer 312 that includes global wiring formed of a metal material between adjacent unit pixels P1 between the first wiring layer 311 and the third wiring layer 313.

[0080] In this manner, in this modified example, an IR pass filter 35 is provided above the photoelectric conversion region 12, thereby improving the light collection rate for the first photoelectric conversion section 10 compared to the above embodiment.

[0081] 5 shows an example in which the IR pass filter 35 has a rectangular cross section, but the present invention is not limited to this. As shown in Fig. 6, the IR pass filter 35 may have a substantially trapezoidal cross section that widens from the first photoelectric conversion unit 10 side toward the second photoelectric conversion unit 20. This can further improve the light collection efficiency for the first photoelectric conversion unit 10.

[0082] (2-2. Modification 2) FIG. 7 is a schematic diagram showing an example of a cross-sectional configuration of a photodetector (photodetector 1B) according to Modification 2 of the present disclosure. FIG. 8 is a schematic diagram showing another example of a cross-sectional configuration of a photodetector (photodetector 1B) according to Modification 2 of the present disclosure. FIG. 9 is a schematic diagram showing an example of a cross-sectional configuration of a photodetector (photodetector 1B) according to Modification 2 of the present disclosure. Like the photodetector 1 of the above embodiment, the photodetector 1B is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0083] In the above-described first modification, an example in which the IR pass filter 35 is disposed in the second wiring layer 312 is shown, but the present invention is not limited to this. In the photodetector 1B of this modification, the IR pass filter 35 is extended to the first surface 11S1 of the semiconductor substrate 11 or its vicinity.

[0084] In this manner, in this modified example, the IR pass filter 35 is extended to the first surface 11S1 of the semiconductor substrate 11 or its vicinity, thereby improving the light collection rate for the first photoelectric conversion section 10 compared to the above modified example 1.

[0085] 8, a light reflecting film 36 may be provided on the inclined side surface of the IR pass filter 35. This makes it possible to further improve the light collection efficiency for the first photoelectric conversion section 10.

[0086] 9, a high refractive index layer 37 may be laminated on the first photoelectric conversion unit 10 side of the IR pass filter 35. The high refractive index layer 37 may be formed using, for example, a material with a higher refractive index than the IR pass filter 35. This can further improve the light collection efficiency for the first photoelectric conversion unit 10.

[0087] 10 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1C) according to Modification 3 of the present disclosure. Similar to the photodetector 1 of the above embodiment, the photodetector 1C is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0088] In the photodetector 1C of this modified example, pad portions 33 and 34 formed using a metal material are extended so as to cover part of the photoelectric conversion region 12. Here, the pad portions 33 and 34 correspond to a specific example of a "light-shielding film" according to an embodiment of the present disclosure.

[0089] In this manner, in this modification, the pad portions 33 and 34 are extended to cover, in plan view, a part of the photoelectric conversion region 12. This enables the unit pixel P1 to detect a phase difference.

[0090] 11 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1D) according to Modification 4 of the present disclosure. Similar to the photodetector 1 of the above embodiment, the photodetector 1D is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0091] In the above embodiment, an example has been shown in which the first photoelectric conversion unit 10 detects wavelengths in the near-infrared band, and the second photoelectric conversion unit 20 detects wavelengths in the visible light band, but the present invention is not limited to this. In the photodetector 1D of this modified example, the second photoelectric conversion unit 20 selectively detects green light, and by arranging red filters 38R or blue filters 38B in parallel in the XY plane in the second wiring layer 312, the corresponding color light is detected in each photoelectric conversion region 12. Even with this configuration, the same effects as in the above embodiment can be obtained.

[0092] (2-5. Modification 5) FIG. 12 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1E) according to Modification 5 of the present disclosure. FIG. 13 is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector (photodetector 1E) according to Modification 5 of the present disclosure. FIG. 14 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1E) according to Modification 5 of the present disclosure. Like the photodetector 1 of the above embodiment, the photodetector 1E is a CMOS image sensor used in electronic devices such as digital still cameras and video cameras.

[0093] In the above embodiment, an example is shown in which the first wiring layer 311 and the third wiring layer 313, which are local wiring, are formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band, and the second wiring layer 312, which is global wiring, is formed using a metal material, but this is not limited to this.

[0094] 12 , the first wiring layer 311, the second wiring layer 312, and the third wiring layer 313 may all be formed using a conductive material that is transparent to wavelengths in at least part of the visible light band and the near-infrared band. As a result, in the photodetector 1E of this modification, although the resistance of the global wiring is higher than in the above embodiment, the loss of light incident on the first photoelectric conversion unit 10 is further reduced, thereby making it possible to further improve the sensitivity of the first photoelectric conversion unit 10 disposed below the multilayer wiring layer 30. Furthermore, in the photodetector 1E of this modification, it is possible to further improve the degree of freedom in the arrangement and wiring layout of the transistors that constitute the readout circuits 13 and 14.

[0095] 12, when the first wiring layer 311, the second wiring layer 312, and the third wiring layer 313 are all formed using a conductive material that is transparent to wavelengths in at least a part of the visible light band and the near-infrared band, for example, wiring can also be arranged above the photoelectric conversion region 12 in the second wiring layer 312 as shown in FIG. 13. In other words, it is possible to further improve the degree of freedom in wiring layout.

[0096] 14 , in addition to the first wiring layer 311 and the third wiring layer 313, a portion of the second wiring layer 312 may be formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band. Specifically, in the second wiring layer 312, the reset lines RSTL1 and RSTL2, the select lines SELL1 and SELL2, the signal lines VSL1 and VSL2, and the power supply line VDD, which are desirably low in resistance, may be formed using a metal material, and the other wiring layers may be formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band. As a result, in the photodetector 1E of this modified example, compared to the above embodiment, it is possible to further improve the sensitivity of the first photoelectric conversion unit 10 disposed below the multilayer wiring layer 30 while suppressing the resistance of the global wiring.

[0097] 3. Application Examples Application Example 1 FIG. 15 shows an example of the overall configuration of the photodetector (for example, photodetector 1) shown in FIG. 1 and the like.

[0098] 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 semiconductor 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.

[0099] 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.

[0100] 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.

[0101] 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 semiconductor substrate 11 through the horizontal signal lines 121.

[0102] 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.

[0103] The circuit portion consisting of the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 may be formed directly on the semiconductor substrate 11, or may be disposed on an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0104] The control circuit 115 receives a clock and data instructing an operation mode from outside the semiconductor 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.

[0105] The input / output terminal 116 is used to exchange signals with the outside.

[0106] (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.

[0107] FIG. 16 is a block diagram showing an example of the configuration of electronic device 1000. As shown in FIG.

[0108] As shown in FIG. 16, the electronic device 1000 includes an optical system 1001, a photodetector 1, and a DSP (Digital Signal Processor) 1002, and is configured by connecting the DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 via a bus 1008, and is capable of capturing still images and moving images.

[0109] 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 .

[0110] The photodetector 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal for each pixel, and supplies the signal to the DSP 1002 as a pixel signal.

[0111] 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.

[0112] 17A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 1. FIG. 17B 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.

[0113] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 17A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the object 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 object 2100 can be obtained from light L1, and distance information between the object 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 .

[0114] 6. Application Example Application Example to an 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.

[0115] FIG. 18 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.

[0116] 18 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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 site, etc.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] The light source device 11203 may also be configured to supply 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. Fluorescence observation can involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (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 supply narrow-band light and / or excitation light compatible with such special light observation.

[0128] FIG. 19 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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 .

[0138] 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.

[0139] 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.

[0140] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] The above describes an example of an endoscopic surgery system to which the technology disclosed herein can be applied. The technology disclosed herein can be applied to the imaging unit 11402 among the components described above. Applying the technology disclosed herein to the imaging unit 11402 improves detection accuracy.

[0146] 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.

[0147] (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).

[0148] FIG. 20 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.

[0149] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 20 , 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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 the passengers of the vehicle or the outside of the vehicle of information. In the example of Fig. 20, 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.

[0159] FIG. 21 is a diagram showing an example of the installation position of the imaging unit 12031.

[0160] In FIG. 21, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0161] 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.

[0162] 21 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] The present disclosure has been described above with reference to the embodiment and modifications 1 to 5, as well as their application or applied examples (hereinafter, "embodiments"). However, the present disclosure is not limited to the above-described embodiments and various modifications are possible. For example, in the above-described embodiments, an example in which the multilayer wiring layer 30 and the second photoelectric conversion section 20 are formed in this order has been described, but the present disclosure is not limited to this. For example, as shown in FIG. 22 , the second photoelectric conversion section 20 may be formed separately and then bonded to the first photoelectric conversion section 10. Specifically, after forming the pad section 33 as described above, the second photoelectric conversion section 20 is formed separately on the side opposite the light incident side S1, including a portion of the multilayer wiring layer 30 including the third wiring layer 313. Next, the pad sections 33, 34 exposed on the respective bonding surfaces of the multilayer wiring layer 30 provided on the first photoelectric conversion section 10 side and the second photoelectric conversion section 20 side are bonded to each other. This electrically connects the first photoelectric conversion section 10 and the second photoelectric conversion section 20. In this case, a bonding interface X1 is formed within the multilayer wiring layer 30.

[0168] In addition, in the above embodiment, color filter layers 43 including red filters 43R, green filters 43G, and blue filters 43B are provided, and red light, green light, and blue light are received, respectively, to obtain a full-color visible light image. However, a black-and-white visible light image may also be obtained without providing color filter layers 43.

[0169] Furthermore, the photodetector of the present disclosure (for example, the photodetector 1) may be in the form of a module in which the imaging section and the signal processing section or the optical system are packaged together.

[0170] Furthermore, in the above-described embodiments, a solid-state imaging device is described as an example that converts the amount of incident light focused on an imaging surface via an optical lens system into an electrical signal on a pixel-by-pixel basis and outputs the signal as a pixel signal. However, the photodetector of the present disclosure is not limited to such a solid-state imaging device. For example, any device may be used that detects and receives light from a subject, generates and accumulates charges according to the amount of received light through photoelectric conversion, and stores the charges. The output signal may be a signal of image information or a signal of ranging information.

[0171] Furthermore, in the above-described embodiment and the like, the first photoelectric conversion unit 10 serving as the first photoelectric conversion unit is an iTOF sensor, but the present disclosure is not limited to this. That is, the first photoelectric conversion unit 10 is not limited to one that detects light having a wavelength in the infrared light range, and may be one that detects light with wavelengths in other wavelength ranges.

[0172] Furthermore, the materials constituting the components of the photodetector of the present disclosure are not limited to those listed in the above embodiments.

[0173] Furthermore, in the above-described embodiment and the like, an example has been shown in which the unit pixel P1 of the first photoelectric conversion unit 10 has a larger planar area than the unit pixel P2 of the second photoelectric conversion unit, but this is not limiting. For example, the area of ​​the unit pixel P1 may be reduced, and the unit pixel P1 and the unit pixel P2 may have the same size.

[0174] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0175] The present technology may also be configured as follows. According to the present technology configured as follows, the loss of light incident on a first photoelectric conversion unit disposed below a wiring layer is reduced. This makes it possible to improve the sensitivity of the first photoelectric conversion unit disposed below. (1) A photodetector comprising: a first photoelectric conversion unit; a second photoelectric conversion unit disposed on the light incident side of the first photoelectric conversion unit; and a multilayer wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the multilayer wiring layer including a wiring layer at least a portion of which is formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band. (2) The photodetector according to (1), wherein the wiring layer includes one or more wirings extending in an in-plane direction within an interlayer insulating layer and one or more vias extending in a thickness direction within the interlayer insulating layer, and at least a portion of the one or more wirings and the one or more vias are formed using the conductive material. (3) The photodetector according to (1) or (2), wherein the multilayer wiring layer includes a first wiring layer electrically connected to the first photoelectric conversion unit, a second wiring layer electrically connected to the first wiring layer, and a third wiring layer electrically connected to the second wiring layer and the second photoelectric conversion unit, wherein within the multilayer wiring layer, the first wiring layer is provided on the first photoelectric conversion unit side, the third wiring layer is provided on the second photoelectric conversion unit side, and the second wiring layer is provided between the first wiring layer and the third wiring layer, at least a portion of the first wiring layer and the third wiring layer is formed using the conductive material, and the second wiring layer is formed using a metal material having a lower electrical resistivity than the first wiring layer and the third wiring layer. (4) The photodetector according to (3), wherein the first wiring layer and the third wiring layer are local wiring, and the second wiring layer is global wiring. (5) The photodetector device according to (3) or (4), wherein the first wiring layer, the second wiring layer, and the third wiring layer have different electrical resistivities, and when the electrical resistivity of the first wiring layer is R1, the electrical resistivity of the second wiring layer is R2, and the electrical resistivity of the third wiring layer is R3, there is a relationship of R2<R3<R1.(6) The photodetector according to any one of (3) to (5), wherein the first wiring layer and the second wiring layer are formed using polysilicon, and the third wiring layer is formed using copper or aluminum. (7) The photodetector according to any one of (3) to (6), wherein the second wiring layer is a mixture of wiring formed using the metal material and wiring formed using the conductive material. (8) The photodetector according to any one of (3) to (7), wherein the multilayer wiring layer includes a readout circuit that reads out charges generated in the first photoelectric conversion unit and a first via extending in a thickness direction within the layer, and at least one of the gate electrodes of one or more transistors constituting the readout circuit and the first via is formed as the first wiring layer using the conductive material. (9) The photodetector according to (8), further comprising a semiconductor substrate on which the first photoelectric conversion unit is provided, wherein the first wiring layer includes one or more wirings, and the first via is connected to at least any of the one or more wirings, the gate electrodes of the one or more transistors, and the semiconductor substrate. (10) The photodetector according to (8) or (9), wherein the multilayer wiring layer includes a power supply line, a vertical signal line, a drive signal line, and a second via electrically connecting the power supply line, the vertical signal line, and the drive signal line to the readout circuit, respectively, and the power supply line, the vertical signal line, the drive signal line, and the second via are formed using the metal material of the second wiring layer. (11) The photodetector according to any one of (3) to (10), wherein a portion of the third wiring layer is provided in a region overlapping the first photoelectric conversion unit in a plan view. (12) The photodetector according to any one of (3) to (11), wherein the multilayer wiring layer further includes an optical filter between the first wiring layer and the third wiring layer, the optical filter selectively transmitting wavelengths in a predetermined wavelength band. (13) The photodetector according to (12), wherein the optical filter selectively transmits wavelengths in a near-infrared band.(14) The photodetector according to any one of (3) to (13), wherein a first optical filter that selectively transmits wavelengths in a first wavelength band among wavelengths transmitted through the second photoelectric conversion unit and a second optical filter that selectively transmits wavelengths in a second wavelength band different from the first wavelength band among wavelengths transmitted through the second photoelectric conversion unit are arranged in parallel in an in-plane direction between the first wiring layer and the third wiring layer. (15) The photodetector according to any one of (12) to (15), wherein the optical filter has a substantially trapezoidal cross-sectional shape that widens from the first photoelectric conversion unit side toward the second photoelectric conversion unit side. (16) The photodetector according to any one of (12) to (15), wherein a light-reflecting film is provided on a side surface of the optical filter. (17) The photodetector according to any one of (12) to (16), wherein the multilayer wiring layer further includes a high-refractive index layer having a higher refractive index than the optical filter, stacked on the first photoelectric conversion unit side or the second photoelectric conversion unit side of the optical filter. (18) The photodetector according to any one of (1) to (17), wherein the first photoelectric conversion unit has a larger planar area than the second photoelectric conversion unit. (19) The photodetector according to any one of (1) to (18), wherein the first photoelectric conversion unit is partially covered by a light-shielding film. (20) The photodetector according to any one of (1) to (19), wherein the first photoelectric conversion unit is a photodiode embedded in a semiconductor substrate, and the second photoelectric conversion unit is a photoelectric conversion layer including an organic material or semiconductor quantum dots. (21) The photodetector according to any one of (1) to (20), wherein the first photoelectric conversion unit has a surface-illuminated structure. (22) An electronic device including a photodetector having a first photoelectric conversion unit, a second photoelectric conversion unit arranged on a light incident side of the first photoelectric conversion unit, and a multilayer wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the multilayer wiring layer including a wiring layer at least a portion of which is formed using a conductive material that is transparent to wavelengths in at least a part of a visible light band and a near-infrared band.

[0176] This application claims priority based on Japanese Patent Application No. 2024-023906, filed on February 20, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0177] 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; a second photoelectric conversion unit arranged on the light incident side of the first photoelectric conversion unit; and a multilayer wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the multilayer wiring layer including a wiring layer at least partially formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band.

2. The photodetector device of claim 1, wherein the wiring layer includes one or more wirings extending in an in-plane direction within the interlayer insulating layer and one or more vias extending in a thickness direction within the interlayer insulating layer, and at least a portion of the one or more wirings and the one or more vias are formed using the conductive material.

3. The photodetector device of claim 1, wherein the multilayer wiring layer includes a first wiring layer electrically connected to the first photoelectric conversion unit, a second wiring layer electrically connected to the first wiring layer, and a third wiring layer electrically connected to the second wiring layer and the second photoelectric conversion unit, and within the multilayer wiring layer, the first wiring layer is provided on the first photoelectric conversion unit side, the third wiring layer is provided on the second photoelectric conversion unit side, and the second wiring layer is provided between the first wiring layer and the third wiring layer, at least a portion of the first wiring layer and the third wiring layer is formed using the conductive material, and the second wiring layer is formed using a metal material having a lower electrical resistivity than the first wiring layer and the third wiring layer.

4. The photodetector device according to claim 3, wherein the first wiring layer and the third wiring layer are local wiring, and the second wiring layer is global wiring.

5. The photodetector device according to claim 3, wherein the first wiring layer, the second wiring layer, and the third wiring layer have different electrical resistivities, and when the electrical resistivity of the first wiring layer is R1, the electrical resistivity of the second wiring layer is R2, and the electrical resistivity of the third wiring layer is R3, there is a relationship R2<R3<R1.

6. The photodetector device according to claim 3, wherein the first wiring layer and the second wiring layer are formed using polysilicon, and the third wiring layer is formed using copper or aluminum.

7. The photodetector according to claim 3, wherein the second wiring layer is a mixture of wiring formed using the metal material and wiring formed using the conductive material.

8. The photodetector device described in claim 3, wherein the multilayer wiring layer includes a readout circuit that reads out charges generated in the first photoelectric conversion portion and a first via extending in the thickness direction within the layer, and at least one of the gate electrodes of one or more transistors constituting the readout circuit and the first via is formed using the conductive material as the first wiring layer.

9. The photodetector device according to claim 8, further comprising a semiconductor substrate on which the first photoelectric conversion section is provided, the first wiring layer including one or more wirings, and the first via being connected to at least one of the one or more wirings, the gate electrodes of the one or more transistors, and the semiconductor substrate.

10. The photodetector device described in claim 8, wherein the multilayer wiring layer includes a power supply line, a vertical signal line, a drive signal line, and a second via that electrically connects the power supply line, the vertical signal line, and the drive signal line to the readout circuit, respectively, and the power supply line, the vertical signal line, the drive signal line, and the second via are formed using the metal material as the second wiring layer.

11. The photodetector according to claim 3, wherein a portion of the third wiring layer is provided in a region that overlaps the first photoelectric conversion portion in a plan view.

12. The photodetector according to claim 3, wherein the multilayer wiring layer further includes an optical filter between the first wiring layer and the third wiring layer that selectively transmits wavelengths in a predetermined wavelength band.

13. The photodetector according to claim 12, wherein the optical filter selectively transmits wavelengths in the near-infrared band.

14. A photodetector device as described in claim 3, wherein a first optical filter that selectively transmits wavelengths in a first wavelength band among the wavelengths that have passed through the second photoelectric conversion unit, and a second optical filter that selectively transmits wavelengths in a second wavelength band different from the first wavelength band among the wavelengths that have passed through the second photoelectric conversion unit, are arranged in parallel in the in-plane direction between the first wiring layer and the third wiring layer.

15. The photodetector according to claim 12, wherein the optical filter has a substantially trapezoidal cross section that widens from the first photoelectric conversion section side toward the second photoelectric conversion section side.

16. The photodetector according to claim 12, wherein a light-reflecting film is provided on the side surface of the optical filter.

17. The photodetector device described in claim 12, wherein the multilayer wiring layer further has a high refractive index layer having a higher refractive index than the optical filter, stacked on the first photoelectric conversion section side or the second photoelectric conversion section side of the optical filter.

18. The photodetector according to claim 1, wherein the first photoelectric conversion section has a larger planar area than the second photoelectric conversion section.

19. The photodetector according to claim 1, wherein the first photoelectric conversion section is partially covered with a light-shielding film.

20. The photodetector device according to claim 1, wherein the first photoelectric conversion unit is a photodiode embedded in a semiconductor substrate, and the second photoelectric conversion unit is a photoelectric conversion layer containing an organic material or semiconductor quantum dots.

21. The photodetector according to claim 1, wherein the first photoelectric conversion portion has a surface-illuminated structure.

22. An electronic device equipped with a photodetector having: a first photoelectric conversion unit; a second photoelectric conversion unit arranged on the light incident side of the first photoelectric conversion unit; and a multilayer wiring layer provided between the first photoelectric conversion unit and the second photoelectric conversion unit, the multilayer wiring layer including a wiring layer at least a portion of which is formed using a conductive material that is transparent to wavelengths in at least a portion of the visible light band and the near-infrared band.

Images