Light detection device

Abstract

A light detection device according to an embodiment of the present disclosure comprises: a semiconductor substrate that has a first surface and a second surface facing each other, and has a pixel part in which a plurality of pixels is arranged in an array and a peripheral part provided around the pixel part; a light guide part that is provided on the first surface side of the semiconductor substrate, includes a plurality of structures each having a size equal to or smaller than the wavelength of incident light and a medium provided so as to fill gaps between the plurality of structures adjacent to each other and having a refractive index different from that of the plurality of structures, and is provided to spread over the pixel part and the peripheral part; a photoelectric conversion part that is formed to be embedded in the semiconductor substrate in each of the plurality of pixels and photoelectrically converts light incident via the light guide part; a light absorption layer that is provided on a surface on the reverse side of the light guide part from the semiconductor substrate side in the peripheral part; and a protection film that covers the surface of the light absorption layer.

Description

Photodetector

[0001] The present disclosure relates to a photodetector having a wavelength separation structure.

[0002] For example, Patent Document 1 discloses an image sensor having a light-shielding film on top of pixels included in an optical black area arranged outside the pixel array.

[0003] JP 2022-74089 A

[0004] Incidentally, there is a demand for improved reliability in photodetection devices used as image sensors.

[0005] It would be desirable to provide a photodetector device that can improve reliability.

[0006] An optical detection device according to one embodiment of the present disclosure includes: a semiconductor substrate having a first surface and a second surface opposite to each other, the semiconductor substrate having a pixel portion in which a plurality of pixels are arranged in an array, and a peripheral portion provided around the pixel portion; a light guide portion provided on the first surface side of the semiconductor substrate, the light guide portion including a plurality of structures each having a size equal to or smaller than the wavelength of incident light and a medium provided so as to fill spaces between adjacent structures and having a refractive index different from that of the plurality of structures, the light guide portion being provided across the pixel portion and the peripheral portion; a photoelectric conversion portion embedded in the semiconductor substrate for each of the plurality of pixels, which performs photoelectric conversion on light incident via the light guide portion; a light absorption layer provided in the peripheral portion on the surface of the light guide portion opposite the semiconductor substrate side; and a protective film covering the surface of the light absorption layer.

[0007] In a photodetector according to an embodiment of the present disclosure, a semiconductor substrate has a pixel section in which a plurality of pixels are arranged in an array and a peripheral section provided around the pixel section, and a light guide section is provided on a first surface side serving as a light incident surface, the light guide section including a plurality of structures each having a size equal to or smaller than the wavelength of the incident light and a medium having a refractive index different from that of the plurality of structures, the light guide section being provided so as to fill the spaces between adjacent structures, and the light guide section is provided across the pixel section and the peripheral section, and a light absorption layer having a surface covered with a protective film is provided on the light guide section in the peripheral section, thereby suppressing surface reflection in the peripheral section.

[0008] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to an embodiment of the present disclosure. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the photodetector shown in FIG. 1. FIG. 3 is a schematic view illustrating an example of a pixel unit and its periphery in the photodetector shown in FIG. 1. FIG. 4 is a diagram illustrating an example of a circuit configuration of a unit pixel of the photodetector shown in FIG. 1. FIG. 5A is a cross-sectional view schematically illustrating an example of a manufacturing process for the photodetector shown in FIG. 1. FIG. 5B is a cross-sectional view schematically illustrating a process subsequent to FIG. 5A. FIG. 5C is a cross-sectional view schematically illustrating a process subsequent to FIG. 5B. FIG. 5D is a cross-sectional view schematically illustrating a process subsequent to FIG. 5C. FIG. 5E is a cross-sectional view schematically illustrating a process subsequent to FIG. 5D. FIG. 5F is a cross-sectional view schematically illustrating a process subsequent to FIG. 5E. FIG. 5G is a cross-sectional view schematically illustrating a process subsequent to FIG. 5F. FIG. 5H is a cross-sectional view schematically illustrating a process subsequent to FIG. 5G. FIG. 5I is a cross-sectional view schematically illustrating a process subsequent to FIG. 5H. FIG. 5J is a cross-sectional view schematically illustrating a process subsequent to FIG. 5I. 5K is a schematic cross-sectional view illustrating a step subsequent to FIG. 5J. FIG. 5L is a schematic cross-sectional view illustrating a step subsequent to FIG. 5K. FIG. 6 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 1 of the present disclosure. FIG. 7 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 2 of the present disclosure. FIG. 8 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 3 of the present disclosure. FIG. 9 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 4 of the present disclosure. FIG. 10 is a schematic cross-sectional view illustrating another example of the configuration of a photodetector according to Modification 4 of the present disclosure. FIG. 11 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 5 of the present disclosure. FIG. 12A is a schematic cross-sectional view illustrating an example of a manufacturing process for the photodetector shown in FIG. 11. FIG. 12B is a schematic cross-sectional view illustrating a step subsequent to FIG. 12A. FIG. 12C is a schematic cross-sectional view illustrating a step subsequent to FIG. 12B. FIG. 13 is a schematic cross-sectional view illustrating an example of a configuration of a photodetector according to Modification 6 of the present disclosure. Fig. 14A is a schematic cross-sectional view showing an example of a manufacturing process for the photodetector shown in Fig. 13. Fig. 14B is a schematic cross-sectional view showing a process subsequent to Fig. 14A. Fig. 14C is a schematic cross-sectional view showing a process subsequent to Fig. 14B. Fig. 15 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 7 of the present disclosure. Fig. 16 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 8 of the present disclosure.17 is a cross-sectional schematic diagram illustrating another example of the configuration of a light detection device according to Modification 8 of the present disclosure. FIG. 18 is a cross-sectional schematic diagram illustrating another example of the configuration of a light detection device according to Modification 8 of the present disclosure. FIG. 19 is a cross-sectional schematic diagram illustrating another example of the configuration of a light detection device according to Modification 8 of the present disclosure. FIG. 21B is a functional block diagram illustrating an example of an electronic device (camera) using the light detection device shown in FIG. 2. FIG. 21C is a schematic diagram illustrating an example of the overall configuration of a light detection system using the light detection device shown in FIG. 2. FIG. 21B is a diagram illustrating an example of the circuit configuration of the light detection system shown in FIG. 21A. FIG. 21B is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 21C is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 21D is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 21E is an explanatory diagram illustrating an example of the installation positions of an outside-vehicle information detection unit and an imaging unit.

[0009] An embodiment of the present disclosure will be described in detail below with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of the components shown in the drawings. The description will be given in the following order: 1. Embodiment (Example of a photodetector having a light-shielding section covered with a protective layer on a peripheral optical layer) 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) 2-6. Modification 6 (Another example of the configuration of the photodetector) 2-7. Modification 7 (Another example of the configuration of the photodetector) 2-8. Modification 8 (Another example of the configuration of the photodetector) 3. Application Examples 4. Application Examples

[0010] 1. Embodiment FIG. 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. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the photodetector 1 illustrated in FIG. 1. FIG. 3 is a schematic diagram illustrating an example of a pixel unit and its surrounding configuration of the photodetector 1 illustrated in FIG. 1. The photodetector 1 is applicable to, for example, a complementary metal oxide semiconductor (CMOS) image sensor used in electronic devices such as digital still cameras and video cameras, and has a pixel unit (pixel unit 100A) in which a plurality of pixels are two-dimensionally arranged in a matrix as an imaging area. The photodetector 1 is, for example, a so-called back-illuminated photodetector in this CMOS image sensor or the like.

[0011] [Schematic Configuration of Photodetector] The photodetector 1 captures incident light (image light) from a subject via an optical lens system (e.g., optical system 1001, see FIG. 20 ), 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 a peripheral section 100B surrounding the pixel section 100A. The peripheral section 100B has, for example, a pixel control section 111, a signal processing section 112, a control section 113, and a processing section 114. The photodetector 1 also has, for example, a plurality of control lines Lread and a plurality of signal lines VSL.

[0012] The pixel section 100A has, for example, a plurality of unit pixels P arranged two-dimensionally in a matrix. In the unit pixels P, for example, a control line Lread (specifically, a row selection line and a reset control line) is wired for each pixel row, and a signal line VSL is wired for each pixel column.

[0013] The control line Lread is a signal line capable of transmitting a signal that controls the unit pixel P, and is connected to the pixel control unit 111 and the pixel P of the pixel section 100A. The control line Lread is configured to transmit a control signal for reading out a signal from the unit pixel P. The control line Lread can also be said to be a drive line (pixel drive line) that transmits a signal that drives the unit pixel P.

[0014] The signal line VSL is a signal line capable of transmitting a signal from the unit pixel P, and is connected to the unit pixel P of the pixel section 100A and the signal processing section 112. In the pixel section 100A, for example, one or more signal lines VSL are wired for each pixel column made up of a plurality of unit pixels P aligned in the vertical direction (column direction). The signal line VSL is configured to be able to transmit a signal output from the unit pixel P. In the photodetector device 1, a plurality of signal lines VSL may be provided for one pixel column.

[0015] The pixel control unit 111 is configured to be able to control each unit pixel P of the pixel unit 100A. The pixel control unit 111 is a control circuit and is configured by a plurality of circuits including, for example, a buffer, a shift register, an address decoder, etc. The pixel control unit 111 generates signals for controlling the unit pixels P and outputs them to each unit pixel P of the pixel unit 100A via a control line Lread. The pixel control unit 111 is controlled by the control unit 113 and controls the unit pixels P of the pixel unit 100A.

[0016] The pixel control unit 111 generates signals for controlling the unit pixels P, such as a signal for controlling the transfer transistor, a signal for controlling the selection transistor, and a signal for controlling the reset transistor of the unit pixel P, and supplies these signals to each unit pixel P via a control line Lread. The pixel control unit 111 can control the reading of pixel signals from each unit pixel P. The pixel control unit 111 can also be referred to as a pixel driving unit configured to be able to drive each unit pixel P. The pixel control unit 111 and the control unit 113 can also be referred to collectively as a pixel control unit.

[0017] The signal processing unit 112 is configured to be able to perform signal processing of input pixel signals. The signal processing unit 112 is a signal processing circuit and includes, for example, a load circuit, an analog-to-digital (AD) conversion circuit, and a horizontal selection switch. The load circuit is, for example, configured by a current source capable of supplying current to the amplification transistor of the unit pixel P. The load circuit, together with the amplification transistor of the unit pixel P, forms, for example, a source follower circuit.

[0018] The signal processing unit 112 may have an amplifier circuit configured to amplify a signal read from the unit pixel P via the signal line VSL. A load circuit, an amplifier circuit, an AD conversion circuit, etc. are provided for each of the multiple signal lines VSL, for example. A load circuit, an amplifier circuit, an AD conversion circuit, etc. may be provided for each pixel column of the pixel unit 100A.

[0019] A signal output from each unit pixel P selected and scanned by the pixel control unit 111 is input to the signal processing unit 112 via a signal line VSL. The signal processing unit 112 can perform signal processing such as AD conversion and correlated double sampling (CDS) of the signal from the unit pixel P. The signal from each unit pixel P transmitted through each signal line VSL is subjected to signal processing by the signal processing unit 112 and output to the processing unit 114.

[0020] The processing unit 114 is configured to be able to perform signal processing on the input signal. The processing unit 114 is a processing circuit, and is configured, for example, by a circuit that performs various types of signal processing on pixel signals. The processing unit 114 may include a processor and a memory. The processing unit 114 performs signal processing on pixel signals input from the signal processing unit 112 and outputs the processed pixel signals. The processing unit 114 can perform various types of signal processing, such as noise reduction processing and gradation correction processing.

[0021] The control unit 113 is configured to be able to control each unit of the photodetector 1. The control unit 113 receives an externally provided clock, data instructing an operation mode, and the like, and can also output data such as internal information of the photodetector 1. The control unit 113 is a control circuit and has, for example, a timing generator configured to be able to generate various timing signals. The control unit 113 performs drive control of the pixel control unit 111, the signal processing unit 112, and the like, based on the various timing signals (pulse signals, clock signals, and the like) generated by the timing generator.

[0022] The pixel unit 100A, the pixel control unit 111, the signal processing unit 112, etc. may be provided on a single substrate. Furthermore, the pixel control unit 111, the signal processing unit 112, the control unit 113, the processing unit 114, etc. may be provided on a single semiconductor substrate, or may be provided separately on multiple semiconductor substrates. The photodetector 1 may have a layered structure formed by stacking multiple substrates. Some or all of the signal processing unit 112, the control unit 113, and the processing unit 114 may be configured integrally.

[0023] 3, the pixel unit 100A has an effective pixel area 100a1 in which a subject image formed by an imaging lens is photoelectrically converted in a photodiode (PD) to generate a signal for generating an image, and a dummy pixel area 100a2 disposed outside the effective pixel area 100a1 to generate pixel signals for assisting image generation. Note that the pixel unit 100A may further have a dummy pixel area outside the dummy pixel area 100a2 that does not generate pixel signals.

[0024] In the peripheral portion 100B, for example, an optical black (OPB) region 100b that outputs a background signal is provided on the periphery of the pixel portion 100A. In the OPB region 100b, for example, a photodiode (PD) is provided, similarly to the pixel portion 100A.

[0025] [Circuit Configuration of Unit Pixel] Fig. 4 shows an example of the circuit configuration of a unit pixel P of the photodetector 1 shown in Fig. 1. The unit pixel P has, for example, one photoelectric conversion unit 12 and a readout circuit 41. The photoelectric conversion unit 12 is configured to receive light and generate a signal. The readout circuit 41 is configured to be able to output a signal based on charges photoelectrically converted. The readout circuit 41 can read out a pixel signal based on the charges photoelectrically converted by the photoelectric conversion unit 12.

[0026] The photoelectric conversion unit 12 is a so-called light receiving element and is configured to be able to generate electric charges by photoelectric conversion. The photoelectric conversion unit 12 is, for example, a photodiode (PD) and converts incident light into electric charges. The photoelectric conversion unit 12 can perform photoelectric conversion to generate electric charges according to the amount of received light.

[0027] The read circuit 41 includes, for example, a transfer transistor TRG, a floating diffusion FD, an amplification transistor AMP, a selection transistor SEL, and a reset transistor RST. The transfer transistor TRG, the amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each a MOS transistor (MOSFET) having a gate, a source, and a drain terminal.

[0028] For example, the transfer transistor TRG, the amplification transistor AMP, the selection transistor SEL, and the reset transistor RST are each configured as an NMOS transistor. Note that each transistor configuring the read circuit 41 may be configured as a PMOS transistor.

[0029] The transfer transistor TRG is configured to be able to transfer charges photoelectrically converted in the photoelectric conversion unit 12 to the floating diffusion FD. The transfer transistor TRG is controlled by a signal STRG to electrically connect or disconnect the photoelectric conversion unit 12 and the floating diffusion FD. The transfer transistor TRG can transfer charges photoelectrically converted and accumulated in the photoelectric conversion unit 12 to the floating diffusion FD.

[0030] The floating diffusion FD is an accumulation unit configured to be able to accumulate transferred charges. The floating diffusion FD can accumulate charges photoelectrically converted by the photoelectric conversion unit 12. The floating diffusion FD can also be considered a holding unit capable of holding the transferred charges. The floating diffusion FD accumulates the transferred charges and converts them into a voltage according to the capacitance of the floating diffusion FD.

[0031] The amplification transistor AMP is configured to generate and output a signal based on the charge accumulated in the floating diffusion FD. The amplification transistor AMP can generate and output a signal based on the charge converted by the photoelectric conversion unit 12.

[0032] The gate of the amplifier transistor AMP is electrically connected to the floating diffusion FD, and the voltage converted by the floating diffusion FD is input to the gate of the amplifier transistor AMP. The drain of the amplifier transistor AMP is connected to, for example, a power supply line to which a power supply voltage VDD is supplied.

[0033] The source of the amplifier transistor AMP is connected to a signal line VSL via a selection transistor SEL. The amplifier transistor AMP is configured to generate a signal based on the charge accumulated in the floating diffusion FD, i.e., a signal based on the voltage of the floating diffusion FD, and output the signal to the signal line VSL.

[0034] The selection transistor SEL is configured to be able to control the output of a pixel signal. The selection transistor SEL is, for example, electrically connected in series with the amplification transistor AMP. The selection transistor SEL is configured to be controlled by a signal SSEL and to be able to output a signal from the amplification transistor AMP to a signal line VSL. The selection transistor SEL can control the output timing of the pixel signal.

[0035] The selection transistor SEL is configured to be able to output a signal based on the charge converted by the photoelectric conversion unit 12. The selection transistor SEL can output a pixel signal of the unit pixel P to a signal line VSL. The selection transistor SEL may be electrically connected in series between a power supply line to which a power supply voltage VDD is applied and the amplification transistor AMP. The selection transistor SEL may also be omitted as appropriate.

[0036] The reset transistor RST is configured to be able to reset the voltage of the floating diffusion FD. The reset transistor RST is, for example, electrically connected to a power supply line to which a power supply voltage VDD is applied, and is configured to reset the charge of the unit pixel P.

[0037] The reset transistor RST is controlled by a signal SRST and can reset the charge accumulated in the floating diffusion FD and reset the voltage of the floating diffusion FD. The reset transistor RST can, for example, electrically connect a power supply line and the floating diffusion FD and discharge the charge accumulated in the floating diffusion FD. The reset transistor RST can also discharge the charge accumulated in the photoelectric conversion unit 12 via the transfer transistor TRG.

[0038] The pixel control unit 111 of the photodetection device 1 supplies control signals to the gates of the transfer transistor TRG, selection transistor SEL, reset transistor RST, etc. of each unit pixel P via the control line Lread, turning the transistors on (conducting state) or off (non-conducting state).

[0039] The multiple control lines Lread for each pixel row of the photodetector 1 include, for example, a wiring for transmitting a signal STRG that controls the transfer transistor TRG, a wiring for transmitting a signal SSEL that controls the selection transistor SEL, and a wiring for transmitting a signal SRST that controls the reset transistor RST.

[0040] The readout circuit 41 may be configured to change the conversion efficiency (gain) when converting electric charge into voltage. For example, the readout circuit 41 may have a switching transistor used to set the conversion efficiency. As an example, the switching transistor is electrically connected between the floating diffusion FD and the reset transistor RST.

[0041] In the readout circuit 41, when the switching transistor is turned on, the capacitance added to the floating diffusion FD of the unit pixel P increases, and the conversion efficiency is switched. The switching transistor can change the capacitance connected to the gate of the amplification transistor AMP to change the conversion efficiency.

[0042] The transfer transistor TRG, selection transistor SEL, reset transistor RST, switching transistor, etc. are on / off controlled by a pixel control unit 111. The pixel control unit 111 controls the readout circuit 41 of each unit pixel P to output a pixel signal from each unit pixel P to a signal line VSL. The pixel control unit 111 can control the reading out of the pixel signal of each unit pixel P to the signal line VSL.

[0043] [Configuration of the Photodetector] As described above, the photodetector 1 is a back-illuminated imaging device. The pixel section 100A includes a plurality of unit pixels P arranged two-dimensionally in a matrix. Each unit pixel P includes, for example, a light-receiving section 10, an optical layer 20 provided on the light-incident side S1 of the light-receiving section 10, and a multilayer wiring layer 40 provided on the side opposite the light-incident side S1 of the light-receiving section 10. As described above, the photodetector 1 includes the pixel section 100A in which the unit pixels P are arranged two-dimensionally in a matrix, and a peripheral section 100B surrounding the pixel section 100A. The light-receiving section 10, the optical layer 20, and the multilayer wiring layer 40 are provided across the pixel section 100A and the peripheral section 100B. The optical layer 20 includes, for example, a light guide section 27 including a plurality of nanostructures 27A and a medium 27B filling the spaces between adjacent structures 27A. In the photodetector 1, as shown in FIG. 3, for example, a light-shielding portion 32 having a surface covered with a protective layer 33 is provided on the light-guiding portion 27 in the peripheral portion 100B.

[0044] Here, light-guiding section 27 corresponds to a specific example of a "light-guiding section" according to one embodiment of the present disclosure. Multiple structures 27A correspond to a specific example of a "multiple structures" according to one embodiment of the present disclosure, and medium 27B corresponds to a specific example of a "medium" according to one embodiment of the present disclosure. Light-shielding section 32 corresponds to a specific example of a "light-absorbing layer" according to one embodiment of the present disclosure, and protective layer 33 corresponds to a specific example of a "protective film" according to one embodiment of the present disclosure.

[0045] The light receiving section 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion sections 12 formed and embedded in the semiconductor substrate 11. The light receiving section 10 further includes a separation section 13.

[0046] The semiconductor substrate 11 is made of, for example, a silicon (Si) substrate. The semiconductor substrate 11 may be an SOI (Silicon On Insulator) substrate, a SiGe (Silicon Germanium) substrate, a SiC (Silicon Carbide) substrate, or the like. The semiconductor substrate 11 may be made of a III-V group compound semiconductor material, or may be formed using other semiconductor materials. A first surface 11S1 of the semiconductor substrate 11 is a light-receiving surface (light incident surface). A second surface 11S2 of the semiconductor substrate 11 is an element formation surface on which elements such as transistors are formed. Gate electrodes, gate insulating films, and the like are provided on the second surface 11S2 of the semiconductor substrate 11.

[0047] The photoelectric conversion unit 12 is, for example, a positive intrinsic negative (PIN) type photodiode (PD), and has a pn junction in a predetermined region of the semiconductor substrate 11. The photoelectric conversion unit 12 is formed by embedding one photoelectric conversion unit 12 in each unit pixel P, for example.

[0048] The separation portion 13 is provided between adjacent unit pixels P. In other words, the separation portion 13 is provided so as to surround the unit pixels P, and is provided in a lattice pattern across the pixel portion 100A and the OPB region 100b around its periphery. The separation portion 13 electrically and optically separates adjacent unit pixels P, and extends, for example, from the first surface 11S1 side of the semiconductor substrate 11 toward the second surface 11S2 side.

[0049] The isolation portion 13 can be formed by diffusing p-type impurities, for example. Alternatively, the isolation portion 13 may have a shallow trench isolation (STI) structure or a full trench isolation (FFTI) structure in which an opening is formed in the semiconductor substrate 11 from the first surface 11S1 side and an insulating film is buried in the opening. An air gap may be formed in the STI structure or the FFTI structure.

[0050] A dielectric layer 14, which also serves to prevent reflection on the first surface 11S1 of the semiconductor substrate 11, is provided on the first surface 11S1 of the semiconductor substrate 11. The dielectric layer 14 may be, for example, a film having a positive fixed charge or a film having a negative fixed charge.

[0051] The dielectric layer 14 may be made of a semiconductor material or a conductive material having a band gap wider than that of the semiconductor substrate 11. Specifically, for example, hafnium oxide (HfO ｘ ), aluminum oxide (AlO ｘ ), zirconium oxide (ZrO ｘ ), tantalum oxide (TaO ｘ ), titanium oxide (TiO ｘ ), lanthanum oxide (LaO ｘ ), praseodymium oxide (PrO ｘ ), cerium oxide (CeO ｘ ), neodymium oxide (NdO ｘ ), promethium oxide (PmO ｘ ), samarium oxide (SmO ｘ ), europium oxide (EuO ｘ ), gadolinium oxide (GdO ｘ ), terbium oxide (TbO ｘ ), dysprosium oxide (DyO ｘ ), holmium oxide (HoO ｘ ), thulium oxide (TmO ｘ ), ytterbium oxide (YbO ｘ ), lutetium oxide (LuO ｘ ), yttrium oxide (YO ｘ ), hafnium nitride (HfN ｘ ), aluminum nitride (AlN ｘ ), hafnium oxynitride (HfO ｘ N ｙ ) and aluminum oxynitride (AlO ｘ N ｙ The dielectric layer 14 may be a single layer film or a laminated film made of different materials.

[0052] The optical layer 20 includes, for example, a partition wall 21, a color filter 22, a light-shielding film 23, a sealing film 24, an insulating layer 25, a planarization layer 26, and a light-guiding section 27, and is configured to guide light incident from the light incident side S1 to the light-receiving section 10 side.

[0053] The partition 21 is a frame body provided at the boundary between adjacent unit pixels P and having an opening 21H for each unit pixel P. In other words, similar to the separation portion 13, the partition 21 is provided so as to surround the unit pixel P, and is provided in a lattice pattern across the pixel portion 100A and the OPB region 100b around its periphery.

[0054] The partition wall 21 is intended to prevent light obliquely incident from the light incident side S1 from leaking into an adjacent unit pixel P. The partition wall 21 is made of a material having a lower refractive index than the color filter 22, for example.

[0055] The partition 21 may also serve as a light shield for the unit pixel P, which determines the optical black level. The partition 21 may also serve as a light shield to suppress noise generation in peripheral circuits provided in the peripheral portion 100B. In this case, the partition 21 may be formed using, for example, a material having light-shielding properties. Examples of such materials include tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), or alloys thereof. Other examples include metal compounds such as TiN. The partition 21 may be configured as, for example, a single-layer film or a multilayer film. When configured as a multilayer film, a layer made of, for example, Ti, tantalum (Ta), W, cobalt (Co), or molybdenum (Mo), or an alloy, nitride, oxide, or carbide thereof, may be provided as an underlayer.

[0056] The color filters 22 selectively transmit light of a predetermined wavelength, and include, for example, a red filter 22R that selectively transmits red light (R), a green filter 22G that selectively transmits green light (G), and a blue filter 22B that selectively transmits blue light (B). Each of the color filters 22R, 22G, and 22B is formed by filling the opening 21H of the partition wall 21 with a resin material in which a desired pigment or dye is dispersed.

[0057] For example, for four unit pixels P arranged in two rows and two columns, two green filters 22G are arranged on a diagonal line, and one red filter 22R and one blue filter 22B are arranged on a diagonal line that intersects the diagonal line. In the unit pixels P provided with the color filters 22R, 22G, and 22B, for example, the corresponding color light is selectively photoelectrically converted in the respective photoelectric conversion units 12.

[0058] That is, in the pixel section 100A, unit pixels P (red pixels Pr) that selectively receive and photoelectrically convert red light (R), unit pixels P (green pixels Pg) that selectively receive and photoelectrically convert green light (G), and unit pixels P (blue pixels Pb) that selectively receive and photoelectrically convert blue light (B) are arranged in a Bayer pattern. The red pixels Pr, green pixels Pg, and blue pixels Pb generate pixel signals of the red light (R) component, the green light (G) component, and the blue light (B) component, respectively. This enables the photodetector 1 to obtain RGB pixel signals.

[0059] The color filters 22 may include complementary color filters that selectively transmit cyan (C), magenta (M), and yellow (Y) in addition to the red filter 22R, green filter 22G, and blue filter 22B. Furthermore, the color filters 22 may include a filter corresponding to white (W), i.e., a filter that transmits light of all wavelengths incident on the photodetector 1. In addition, the color filters 22 may include a filter that selectively transmits infrared light.

[0060] The thickness of the color filter 22 may be different for each color, taking into consideration the color reproducibility and sensor sensitivity of the optical spectrum.

[0061] The light-shielding film 23 is intended to block light incident on the photoelectric conversion unit 12 provided in the OPB region 100b. The light-shielding film 23 is provided in the OPB region 100b between the light-receiving unit 10 (specifically, the dielectric layer 14) and the partition wall 21 and color filter 22. The light-shielding film 23 can be formed using, for example, tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), or an alloy thereof.

[0062] The OPB region 100n is further provided with a sealing film 24 that covers the partition walls 21, the color filters 22, and the light-shielding film 23. The sealing film 24 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or the like.

[0063] The insulating layer 25 is provided between the light receiving unit 10 and the light guiding unit 27. The insulating layer 25 is formed across the pixel unit 100A and the peripheral unit 100B so as to be stacked on, for example, the partition walls 211 and the color filters 22 provided in the pixel unit 100A, and the sealing film 24 that covers the partition walls 211, the color filters 22, and the light-shielding film 23 provided in the OPB region 100b. The insulating layer 25 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), or the like.

[0064] The insulating layer 25 may be formed using a low refractive index material other than the above insulating materials, or may be formed using other materials that transmit light in the wavelength range to be measured. The insulating layer 25 can also be called a transparent layer or spacer layer that transmits light.

[0065] 5D , the planarization layer 26 serves to fill in steps in the insulating layer 25 that are generated when the insulating layer 25 is provided so as to cover the partition walls 211, the color filters 22, and the sealing film 24 that covers the partition walls 21, the color filters 22, and the light-shielding film 23, thereby planarizing the surface. The planarization layer 26 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), or the like.

[0066] The light guide unit 27 is configured as, for example, a light guide element that can guide light by imparting a phase delay to incident light. The light guide unit 27 is a light guide element that utilizes metamaterial (metasurface) technology. The light guide unit 27 can also be referred to as a metasurface layer (or metamaterial layer). In the photodetector 1, for example, as shown in FIG. 1 , the light guide unit 27 is provided across the pixel unit 100A and the peripheral unit 100B.

[0067] The light guiding unit 27 has a plurality of structures 27A and a medium 27B provided around the plurality of structures 27A. The light guiding unit 27 uses the plurality of structures 27A, which are nanostructures, to propagate light toward the photoelectric conversion unit 12. Light from a subject, which is the object to be measured, is incident on the light guiding unit 27. For example, light that has passed through an optical system such as an imaging lens is incident on the plurality of structures 27A. The plurality of structures 27A have a size equal to or smaller than a predetermined wavelength of the incident light, for example, a size equal to or smaller than the wavelength range of visible light. Note that the plurality of structures 27A may also have a size equal to or smaller than the wavelength range of infrared light.

[0068] Each of the plurality of structures 27A is, for example, a columnar (pillar-shaped) structure, and can be referred to as a nanopillar. The plurality of structures 27A can be referred to as a metasurface element. As an example, the plurality of structures 27A have a cylindrical shape. The plurality of structures 27A are arranged side by side in the X-axis direction or the Y-axis direction, with the medium 27B sandwiched therebetween.

[0069] The shape of the plurality of structures 27A can be changed as appropriate, and may be a circle or a rectangle in a plan view, or may be an ellipse, a polygon, a cross, or any other shape.

[0070] The multiple structures 27A are also referred to as metaatoms, nanoatoms, nanoposts, metasurface structures, microstructures, etc.

[0071] The medium 27B is provided so as to fill the periphery of the plurality of structures 27A. The plurality of structures 27A are provided within the medium 27B, and can be said to be arranged by replacing part of the medium 27B. The medium 27B can also be said to be a medium layer or a protective layer (protective member).

[0072] In the light-guiding section 27, a plurality of structures 27A are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 27A are provided in the X-axis direction and the Y-axis direction at intervals equal to or less than the wavelength range of visible light. Note that in the unit pixel P, the plurality of structures 27A may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0073] The structures 27A have a refractive index that is different from the refractive index of the surrounding medium 27B. For example, the structures 27A have a refractive index that is higher than the refractive index of the medium 27B.

[0074] Examples of materials that can be used to form the structures 27A include titanium oxide (TiO), silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), and germanium (Ge).

[0075] The plurality of structures 27A may be formed using a single element such as titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), or niobium (Nb), or an oxide, nitride, or oxynitride thereof, or a composite thereof. The plurality of structures 27A may be formed by including other metal compounds (metal oxides, metal nitrides, etc.).

[0076] The plurality of structures 27A may be formed using GaP, GaN, GaAs, SiC, etc. The plurality of structures 27A may be formed using silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), oxygen-doped silicon carbide (SiOC), or other silicon compounds. The plurality of structures 27A may be formed using different materials.

[0077] The medium 27B is made of, for example, an inorganic material such as an oxide, a nitride, or an oxynitride. The medium 27B may be made of, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), oxygen-doped silicon carbide (SiOC), or other silicon compounds. The medium 27B may also be made of TEOS.

[0078] The medium 27B may be formed using a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The medium 27B may be made of a material in which any of these resins contains fluorine. The medium 27B may be formed using a material in which any of these resins is filled with beads (filler) having a refractive index higher (or lower) than that of the resin.

[0079] The materials of the plurality of structures 27A and the medium 27B can be selected depending on the refractive index difference with the surrounding medium, the wavelength range of the incident light to be measured, etc. Note that a portion of the plurality of structures 27A and the medium 27B may be made using air. For example, the plurality of structures 27A may be made to include air (voids).

[0080] The light-guiding unit 27 can control the wavefront of the light by, for example, causing a phase delay in the incident light due to a difference in refractive index between the plurality of structures 27A and the medium surrounding them. The light-guiding unit 27 can adjust the propagation direction of the light by, for example, imparting a phase delay to the incident light using the plurality of structures 27A and the medium 27B.

[0081] The materials of the plurality of structures 27A and medium 27B (optical constants of each material), the size (width (diameter), height, etc.) and pitch (arrangement interval) of the plurality of structures 27A, etc. are determined so that light of a desired wavelength range among incident light from the measurement target travels in a desired direction. For example, the material (refractive index), dimensions, pitch, and material (refractive index) of the plurality of structures 27A and medium 27B can be set.

[0082] As an example, in the photodetector 1, the material, size, arrangement number, etc. of the plurality of structures 27A in each unit pixel P are determined so that light in a specific wavelength band to be detected travels to the photoelectric conversion unit 12 of the desired unit pixel P. For example, the plurality of structures 27A provided in the red pixel Pr, the green pixel Pg, and the blue pixel Pb may be formed so as to have different sizes (e.g., width, height), arrangement positions, etc.

[0083] The light guide 27 may be configured as, for example, a spectroscopic unit (spectroscopic element) capable of separating incident light. The optical layer 20 (or the light guide 27) may also be referred to as a splitter (color splitter). The optical layer 20 may also be referred to as a color splitter layer or a wavelength separation layer. The optical layer 20 (or the light guide 27) may also be referred to as an optical element configured to redirect light.

[0084] On the light incident side S1 of the optical layer 20, a protective layer 31, a light blocking portion 32, and a protective layer 33 are provided in this order.

[0085] The protective layer 31 is provided to protect the surface of the light guide section 27, and is provided across the pixel section 100A and the peripheral section 100B. The protective layer 31 is configured, for example, of a single layer film made of any of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), etc., or a laminated film made of two or more of these materials.

[0086] The light-shielding portion 32 is intended to prevent surface reflection in the peripheral portion 100B. For example, as shown in FIG. 3 , the light-shielding portion 32 is provided in the peripheral portion 100B so as to surround the pixel portion 100A, and the surface thereof is covered with a protective layer 33.

[0087] The light-shielding portion 32 is formed of, for example, a black color filter or a metal film having light-shielding properties, such as tungsten (W). Examples of materials for the black color filter include titanium oxide filler dispersed resin, carbon black pigment dispersed resin, and organic pigment dispersed resin. The thickness of the light-shielding portion 32 is, for example, 0.1 μm or more and 3 μm or less.

[0088] The protective layer 33 is intended to prevent surface reflection in the light-shielding portion 32. The protective layer 33 covers the surface of the light-shielding portion 32, specifically, the top and side surfaces of the light-shielding portion 32, and extends onto the surrounding protective layer 31.

[0089] The protective layer 33 is configured to include, for example, any one of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), oxygen-doped silicon carbide (SiOC), nitrogen-doped silicon carbide (SiNC), aluminum oxide (AlO), hafnium oxide (HfO), tantalum oxide (TaO), and indium oxide (InO).

[0090] The multilayer wiring layer 40 is stacked on the semiconductor substrate 11. The multilayer wiring layer 40 includes, for example, a conductor film and an insulating film, and has a plurality of wires and vias. The multilayer wiring layer 40 has a configuration in which a plurality of wires are stacked with an insulating film interposed therebetween as an interlayer insulating film. The multilayer wiring layer 40 includes, for example, two or three or more layers of wires.

[0091] The wiring of the multilayer wiring layer 40 is formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring of the multilayer wiring layer 40 may be formed using polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), or silicon oxynitride (SiON).

[0092] The semiconductor substrate 11 and the multilayer wiring layer 40 are provided with the above-described readout circuit 41, for example, for each unit pixel P or for each plurality of unit pixels P. In addition to the above-described readout circuit 41, the multilayer wiring layer 40 may also be formed with, for example, a pixel control unit 111, a signal processing unit 112, a control unit 113, a processing unit 114, and the like.

[0093] [Method of Manufacturing Photodetector] FIGS. 5A to 5L show the steps of a method of manufacturing the photodetector 1 in order of process.

[0094] First, as shown in Fig. 5A, partition walls 21, color filters 22, light-shielding films 23, and sealing films 24 are formed on the first surface 11S1 of the semiconductor substrate 11. Next, as shown in Fig. 5B, an insulating layer 25 is formed by, for example, chemical vapor deposition (CVD), and then, as shown in Fig. 5C, a planarizing layer 26 is formed on the insulating layer 25 by, for example, CVD.

[0095] 5D, the surface of the planarization layer 26 is planarized by, for example, chemical mechanical polishing (CMP). Next, as shown in FIG. 5E, a medium 27B made of a low refractive index material (e.g., SiN / TEOS) is formed on the planarization layer 26. Next, as shown in FIG. 5F, a hard mask 51 is patterned on the medium 27B by photolithography, and then the medium 27B is processed by, for example, dry etching to form an opening 27H.

[0096] Next, as shown in FIG. 5G, the hard mask 51 is removed, and then, as shown in FIG. 5H, a high refractive index material (e.g., TiO ２ 5I, the high refractive index film formed on medium 27B is removed by, for example, CMP, thereby forming light guide 27 in which multiple structures 27A are embedded in medium 27B.

[0097] Next, as shown in Fig. 5J, a protective layer 31 is formed on the light-guiding portion 27 by, for example, sputtering. Subsequently, as shown in Fig. 5K, a light-shielding portion 32 is formed in the peripheral portion 100B by, for example, photolithography. Next, as shown in Fig. 5L, a continuous protective layer 33 is formed on the protective layer 31 and the light-shielding portion 32 by, for example, sputtering. This completes the photodetector shown in Fig. 1.

[0098] The above-described manufacturing method is merely an example, and other manufacturing methods may be adopted.

[0099] [Functions and Effects] In the photodetector 1 of this embodiment, a light-shielding portion 32 whose surface is covered with a protective layer 33 is provided on a light-guiding portion 27 configured to include a plurality of structures 27A and a medium 27B filling the spaces between adjacent structures 27A, the light-guiding portion 27 being provided on the first surface 11S1 side of the semiconductor substrate 11 in which a photoelectric conversion portion 12 is embedded and formed for each unit pixel P. This will be described below.

[0100] In recent years, as a countermeasure to the decrease in pixel sensitivity due to the advancement of miniaturization, a technology has been attracting attention that uses nanopost structures to scatter light and spatially separate wavelengths, thereby increasing the effective light-collecting area of ​​each color beyond that of a single pixel. Nanopost structures have a high refractive index relative to the surrounding medium, which creates a phase difference between the nanopost structure and the medium according to wavelength. Therefore, by optimizing the radius, length, and arrangement of the nanoposts, it is possible to distribute the visible wavelength band corresponding to each color pixel that makes up the pixel unit. This allows for higher sensitivity compared to full-color image sensors that acquire RGB color information using conventional color filters.

[0101] Incidentally, a technology has been reported in which, outside the so-called active pixel region that outputs image signals for image generation, a pixel signal to assist image generation or a dummy pixel region or optical black (OPB) region that does not output pixel signals is placed, and a medium including nanopost structures is extended up to the top of the region to protect the pixels from contamination during the manufacturing process.

[0102] However, if the medium containing the nanopost structures is extended outside the effective pixel area, there is a concern that reflection from the medium surface will worsen flare. There is also a concern that image quality will be degraded by stray light generated by reflection near the surface of the semiconductor substrate on which the light receiving section is formed below the nanopost structures. To address these concerns, as mentioned above, a method has been disclosed in which a light-shielding film is provided above the pixels included in the OPB area to block light incident on the pixels included in the OPB area, but this method does not provide a sufficient effect against flare.

[0103] In contrast, in this embodiment, a light-shielding portion 32 having a surface covered with a protective layer 33 is provided on the light-guiding portion 27, which includes a plurality of structures 27A and a medium 27B filling the spaces between adjacent structures 27A and extends to the peripheral portion 100B. This suppresses surface reflection in the peripheral portion. For example, the photodetector 1 can reduce reflectance by, for example, 90% compared to a case in which a light-shielding film is provided on the top of the pixels included in the OPB region, as described above. Furthermore, the reflectance can be reduced by, for example, 50% compared to a case in which a bare light-shielding portion 32 not covered with the protective layer 33 is provided on the light-guiding portion 27 extending to the peripheral portion 100B.

[0104] As described above, in the photodetector 1 of this embodiment, surface reflection in the peripheral portion 100B can be suppressed, and therefore, stray light due to reflection in the vicinity of the first surface 11S1 of the semiconductor substrate 11, as well as flare due to surface reflection in the light guiding portion 27 extending to the peripheral portion 100B, can be sufficiently reduced. This makes it possible to improve reliability.

[0105] Next, Modifications 1 to 8 and application examples of the present disclosure will be described. In the following, the same components as those in the above embodiment will be given the same reference numerals, and the description thereof will be omitted as appropriate.

[0106] 6 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1A) according to a first modification of the present disclosure. The photodetector 1A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0107] In the above embodiment, an example in which the protective layer 33 is provided to cover the upper surface and side surfaces of the light-shielding portion 32 with a substantially uniform thickness is shown, but the present invention is not limited to this. In the light-detecting device 1A of this modification, a protective layer 63 having a plurality of microlenses 63L is provided on the light-shielding portion 32.

[0108] In this way, in this modification, a plurality of microlenses 63L are provided above the light-shielding portion 32, and the scattering effect of the microlenses 63L can further suppress surface reflection in the light-shielding portion 32. This makes it possible to improve reliability.

[0109] 7 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1B) according to a second modification of the present disclosure. The photodetector 1B is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0110] In the above embodiment, an example in which the protective layer 33 is provided to cover the upper surface and side surfaces of the light-shielding portion 32 with a substantially uniform thickness is shown, but the present invention is not limited to this. In the light-detecting device 1B of this modified example, a protective layer 73 having a concave-convex structure 73X is provided on the light-shielding portion 32.

[0111] In this manner, in this modification, the concave-convex structure 73X is provided above the light-shielding portion 32, which can further suppress surface reflection in the light-shielding portion 32. This makes it possible to improve reliability.

[0112] 8 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1C) according to a third modification of the present disclosure. The photodetector 1C is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0113] In the above embodiment, an example in which the protective layer 33 is provided to cover the upper surface and side surfaces of the light-shielding portion 32 with a substantially uniform thickness is shown, but the present invention is not limited to this. In the photodetector 1C of this modified example, a multilayer interference film 83 is further laminated on the protective layer 33 that covers the light-shielding portion 32.

[0114] The multilayer interference film 83 has a configuration in which layers having different refractive indices are alternately stacked. As an example, the multilayer interference film 83 may be a multilayer film in which silicon oxide films and oxynitride films are alternately stacked, or a multilayer film in which silicon oxide films and tantalum oxide films are alternately stacked.

[0115] In this way, in this modification, the multilayer interference film 83 is further laminated on the protective layer 33, which can further suppress surface reflection in the light-shielding portion 32. Therefore, it is possible to improve reliability.

[0116] (2-4. Modification 4) Fig. 9 is a schematic diagram showing an example of a cross-sectional configuration of a photodetector according to Modification 4 of the present disclosure (photodetector 1D). Fig. 10 is a schematic diagram showing another example of a cross-sectional configuration of a photodetector according to Modification 4 of the present disclosure (photodetector 1E). The photodetectors 1D and 1E are, for example, CMOS image sensors used in electronic devices such as digital still cameras and video cameras, and are, for example, so-called back-illuminated photodetectors, similar to the above-described embodiment.

[0117] In the above embodiment, an example in which light guiding section 27 consisting of one layer is provided has been described, but the present invention is not limited to this. Photodetector devices 1D and 1E of this modification differ from the above embodiment in that light guiding sections are stacked in two or three stages (light guiding sections 27, 28, and 29).

[0118] Like the light guide unit 27, the light guide units 28 and 29 are configured as light guide elements that can, for example, impart a phase delay to incident light and guide the light. The light guide units 28 and 29 are light guide elements that utilize metamaterial (metasurface) technology. The light guide units 28 and 29 can also be referred to as metasurface layers (or metamaterial layers). In the photodetector devices 1D and 1D, like the light guide unit 27 of the above embodiment, the light guide units 28 and 29 are provided across the pixel unit 100A and the peripheral unit 100B.

[0119] The light guides 28 and 29 each include a plurality of structures 28A and 29A and a medium 28B and 29B surrounding the plurality of structures 28A and 29A. The light guides 28 and 29 utilize the plurality of structures 28A and 29A, which are nanostructures, to propagate light toward the photoelectric conversion unit 12. Light from a subject, which is a measurement target, is incident on the light guides 28 and 29. For example, light that has passed through an optical system such as an imaging lens is incident on the plurality of structures 28A and 29A. The plurality of structures 28A and 29A have a size equal to or smaller than a predetermined wavelength of the incident light, for example, a size equal to or smaller than the wavelength range of visible light. Note that the plurality of structures 28A and 29A may also have a size equal to or smaller than the wavelength range of infrared light.

[0120] The plurality of structures 28A, 29A are each, for example, columnar (pillar-shaped) structures, and can be referred to as nanopillars. The plurality of structures 28A, 29A can be referred to as metasurface elements. As an example, the plurality of structures 28A, 29A have a cylindrical shape. The plurality of structures 28A, 29A are arranged side by side in the X-axis direction or the Y-axis direction, with the medium 28B, 29B sandwiched therebetween.

[0121] The shapes of the plurality of structures 28A, 29A can be changed as appropriate, and may be circular or rectangular in plan view, or may be elliptical, polygonal, cross-shaped, or any other shape.

[0122] The multiple structures 28A, 29A are also referred to as metaatoms, nanoatoms, nanoposts, metasurface structures, microstructures, etc.

[0123] The media 28B and 29B are provided so as to fill the peripheries of the plurality of structures 28A and 29A, respectively. The plurality of structures 28A and 29A are provided within the media 28B and 29B, respectively, and can be said to be arranged by replacing part of the media 28B and 29B. The media 28B and 29B can also be said to be medium layers or protective layers (protective members).

[0124] In the light guide sections 28, 29, a plurality of structures 28A, 29A are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 28A, 29A are provided in the X-axis direction and the Y-axis direction at intervals equal to or less than the wavelength range of visible light. Note that in the unit pixel P, the plurality of structures 28A, 29A may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0125] The structures 28A, 29A have a refractive index that is different from the refractive index of the surrounding medium 28B, 29B. For example, the structures 28A, 29A have a refractive index that is higher than the refractive index of the surrounding medium 28B, 29B.

[0126] Examples of materials that can be used to form the structures 28A and 29A include titanium oxide (TiO), silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), and germanium (Ge).

[0127] The plurality of structures 28A, 29A may be formed from a single element such as titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), niobium (Nb), or the like, or from an oxide, nitride, oxynitride, or composite thereof. The plurality of structures 28A, 29A may also be formed from other metal compounds (metal oxides, metal nitrides, etc.).

[0128] The plurality of structures 28A, 29A may be formed using GaP, GaN, GaAs, SiC, etc. The plurality of structures 28A, 29A may be formed using silicon oxide, silicon nitride, silicon nitride oxide, silicon carbide, silicon oxide carbide, or other silicon compounds. The plurality of structures 28A, 29A may be configured using different materials.

[0129] The media 28B and 29B are made of, for example, an inorganic material such as an oxide, a nitride, or an oxynitride. The media 28B and 29B may also be made of, for example, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon oxide carbide, or other silicon compounds. The media 28B and 29B may also be made of TEOS.

[0130] The media 28B, 29B may be made of a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The media 28B, 29B may be made of a material in which any of these resins contains fluorine. The media 28B, 29B may be formed of a material in which any of these resins is filled with beads (filler) having a refractive index higher (or lower) than that of the resin.

[0131] The materials of the plurality of structures 28A, 29A and the media 28B, 29B can be selected depending on the refractive index difference with the surrounding medium, the wavelength range of the incident light to be measured, etc. Note that a portion of the plurality of structures 28A, 29A and the media 28B, 29B may be formed using air. For example, the plurality of structures 28A, 29A may be formed to include air (voids).

[0132] The light guide units 27, 28, and 29 are configured, for example, as light guide elements capable of imparting a phase delay to incident light and guiding the light. In the photodetector devices 1D and 1E, the plurality of structures 27A, 28A, and 29A and the media 27B, 28B, and 29B are arranged so as to impart a desired phase profile to the incident light. For example, the materials (optical constants of each material) of the plurality of structures 27A, 28A, and 29A and the media 27B, 28B, and 29B, the sizes (width (diameter), height, etc.) and pitch (arrangement interval) of the plurality of structures 27A, 28A, and 29A and the media 27B, 28B, and 29B, and the like are determined so that light in the wavelength band to be detected is focused onto the photoelectric conversion unit 12. For example, the materials (refractive index), dimensions, and pitch of the plurality of structures 27A, 28A, and 29A, the materials (refractive index) of the media 27B, 28B, and 29B, and the like can be set.

[0133] Protective layers 34, 35 are provided between light guide section 27 and light guide section 28, and between light guide section 28 and light guide section 29, respectively. Protective layers 34, 35 are configured, for example, as a single layer film made of any of silicon oxide, silicon nitride, silicon oxynitride, etc., or as a laminate film made of two or more of these materials. Note that protective layers 34, 35 may be omitted as appropriate.

[0134] In this manner, in this modification, a light guiding section having a multi-stage structure is provided on the first surface 11S1 side of semiconductor substrate 11. Even in this configuration, by providing light-shielding section 32 whose surface is covered with protective layer 33 on the uppermost light guiding section (here, light guiding section 28 or light guiding section 29), it is possible to obtain the same effect as in the above embodiment.

[0135] 11 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1F) according to a fifth modification of the present disclosure. The photodetector 1F is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0136] In the above-described fourth modification, the light guides are stacked in two or three stages (light guides 27, 28, and 29), and light shielding section 32, the surface of which is covered with protective layer 33, is provided only on the uppermost light guide (here, light guide 28 or light guide 29). However, the present invention is not limited to this. In the photodetector 1F of this modification, light shielding section 36 is also provided on light guide 27, which is a layer below uppermost light guide 28.

[0137] 12A to 12C show the manufacturing method of the photodetector 1F in the order of steps.

[0138] First, in the same manner as in the above embodiment, the light guide section 27 is formed. Next, as shown in Fig. 12A, for example, a recessed section 27X of a predetermined depth is formed in the medium 27B extending to the peripheral section 100B using photolithography and etching.

[0139] 12B, light-shielding portion 36 is formed by, for example, sputtering to fill dug portion 27X, and then light-shielding portion 36 formed on light-guiding portion 27 is removed by, for example, CMP, and the surface is planarized. Next, as shown in FIG. 12C, protective layer 34 and medium 28B are sequentially formed, and then multiple structures 28A, protective layer 31, light-shielding portion 32, and protective layer 33 are sequentially formed in the same manner as in the above embodiment. This completes photodetector 1F shown in FIG. 11.

[0140] The above-described manufacturing method is merely an example, and other manufacturing methods may be adopted.

[0141] In this manner, in this modification, in addition to the light-shielding portion 32 provided on the uppermost light-guiding portion (here, light-guiding portion 28), a light-shielding portion 36 is also provided between light-guiding portion 27 having a multi-stage structure and light-guiding portion 28. Even with this configuration, the same effects as those of the above embodiment can be obtained.

[0142] 13 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1G) according to Modification 6 of the present disclosure. The photodetector 1G is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0143] In the above-described modified example 5, the light-shielding portion 36 is embedded in the medium 27B of the light-guiding portion 27 below the uppermost light-guiding portion 28, but the present invention is not limited to this. In the photodetector 1G of this modified example, the light-shielding portion 36 is provided on the medium 27B.

[0144] 14A to 14C show the manufacturing method of the photodetector 1G in the order of steps.

[0145] First, similarly to the above embodiment, the light guide section 27 is formed. Next, as shown in Fig. 14A, the light shielding section 32 is formed in the peripheral section 100B by using, for example, photolithography. Subsequently, as shown in Fig. 14B, for example, the protective layer 34 and the medium 28B are sequentially formed.

[0146] 14C, the surface of medium 28B is planarized using, for example, CMP. Thereafter, similarly to the above embodiment, a plurality of structures 28A, protective layer 31, light-shielding portion 32, and protective layer 33 are sequentially formed. In this manner, the photodetector 1G shown in FIG. 13 is completed.

[0147] The above-described manufacturing method is merely an example, and other manufacturing methods may be adopted.

[0148] In this manner, in this modification, the light-shielding portion 36 between the light-guiding portion 27 and the light-guiding portion 28 having a multi-stage structure is provided on the light-guiding portion 27. Even with this configuration, the same effects as those of the above embodiment can be obtained.

[0149] 15 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1H) according to Modification 7 of the present disclosure. The photodetector 1H is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector, similar to the above embodiment.

[0150] In the above-mentioned modified examples 5 and 6, an example was shown in which the light-shielding portion 36 was formed in the medium 27B of the light-guiding portion 27 below the uppermost light-guiding portion 28, but it is also possible to form the light-shielding portion 37 on the first surface 11S1 of the semiconductor substrate 11.

[0151] In this manner, in this modification, the light-shielding portion 37 is formed on the first surface 11S1 of the semiconductor substrate 11. Even with this configuration, the same effects as those of the above embodiment can be obtained.

[0152] (2-8. Modification 8) FIG. 16 is a schematic diagram showing an example of a cross-sectional configuration of a photodetector according to Modification 8 of the present disclosure (photodetector 1I). FIG. 17 is a schematic diagram showing another example of a cross-sectional configuration of a photodetector according to Modification 8 of the present disclosure (photodetector 1J). FIG. 18 is a schematic diagram showing another example of a cross-sectional configuration of a photodetector according to Modification 8 of the present disclosure (photodetector 1K). FIG. 19 is a schematic diagram showing another example of a cross-sectional configuration of a photodetector according to Modification 8 of the present disclosure (photodetector 1L). The photodetectors 1I, 1J, 1K, and 1L are, for example, CMOS image sensors used in electronic devices such as digital still cameras and video cameras, and are, for example, so-called back-illuminated photodetectors, similar to the above-described embodiment.

[0153] The light-shielding portions 32, 36, and 37 shown in the above-described embodiment and modifications 1 to 7 may be electrically connected to the semiconductor substrate 11 by, for example, through-wiring 38 that reaches the semiconductor substrate 11.

[0154] Even with this configuration, the same effects as those of the above embodiment can be obtained.

[0155] <3. Application Examples>

[0156] (Application Example 1) Furthermore, the photodetector 100 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.

[0157] FIG. 20 is a block diagram showing an example of the configuration of electronic device 1000. As shown in FIG.

[0158] As shown in FIG. 20 , electronic device 1000 includes an optical system 1001, a photodetector 100, and a DSP (Digital Signal Processor) 1002. DSP 1002, memory 1003, a display device 1004, a recording device 1005, an operation system 1006, and a power supply system 1007 are connected via a bus 1008, and is capable of capturing still and moving images.

[0159] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from an object and forms an image on the imaging surface of the photodetector 100 .

[0160] The photodetector 100 converts the amount of incident light that is 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.

[0161] The DSP 1002 performs various signal processing on the signal from the photodetector 100 to acquire an image, and temporarily stores the image data in a memory 1003. The image data stored in the memory 1003 is recorded in a recording device 1005 or supplied to a display device 1004 to display the image. An operation system 1006 accepts various operations by a user and supplies operation signals to each block of the electronic device 1000, and a power supply system 1007 supplies power necessary to drive each block of the electronic device 1000.

[0162] 21A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 100. FIG. 21B 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 100 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.

[0163] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by a subject (object to be measured) 2100 ( FIG. 21A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the subject 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be mounted, for example, on 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 .

[0164] 4. Application Example Application Example to Endoscopic Surgery System The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0165] FIG. 22 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.

[0166] 22 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] FIG. 23 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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 .

[0188] 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.

[0189] 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.

[0190] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] (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).

[0198] FIG. 24 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.

[0199] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 24, 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.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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. 24, 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.

[0209] FIG. 25 is a diagram showing an example of the installation position of the imaging unit 12031.

[0210] In FIG. 25, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0211] 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.

[0212] 25 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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] Although the present disclosure has been described above by way of the embodiment, modifications 1 to 8, and application examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, while modifications 1 to 4 have been described above as modifications of the first embodiment, the configurations of each modification and the second embodiment can be combined as appropriate.

[0218] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0219] The present disclosure may also be configured as follows. According to the present technology configured as follows, it is possible to improve reliability. (1) A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, a pixel portion in which a plurality of pixels are arranged in an array, and a peripheral portion provided around the pixel portion; a light guide portion provided on the first surface side of the semiconductor substrate, the light guide portion including a plurality of structures each having a size equal to or smaller than the wavelength of incident light and a medium having a refractive index different from that of the plurality of structures, the light guide portion being provided so as to fill the spaces between adjacent structures and being provided across the pixel portion and the peripheral portion; a photoelectric conversion portion embedded in the semiconductor substrate for each of the plurality of pixels, which performs photoelectric conversion of light incident via the light guide portion; a light absorption layer provided in the peripheral portion on a surface of the light guide portion opposite the semiconductor substrate side; and a protective film covering the surface of the light absorption layer. (2) The photodetector according to (1), wherein the light absorption layer is made of a black color filter or a tungsten film. (3) The photodetector according to (2), wherein the black color filter contains a titanium oxide filler-dispersed resin, a carbon black pigment-dispersed resin, or an organic pigment-dispersed resin. (4) The photodetector according to any one of (1) to (3), wherein the protective film contains any one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, oxygen-doped silicon carbide, nitrogen-doped silicon carbide, aluminum oxide, hafnium oxide, tantalum oxide, indium oxide, and indium oxide. (5) The photodetector according to any one of (1) to (4), further comprising an on-chip lens layer between the light absorption layer and the protective film. (6) The photodetector according to any one of (1) to (5), wherein the protective film has a concave-convex structure above the light absorption layer. (7) The photodetector according to any one of (1) to (6), wherein the protective film is a multilayer interference film in which layers having different refractive indices are stacked. (8) The photodetector according to any one of (1) to (7), wherein the protective film extends from the surface of the light absorption layer to the pixel portion.(9) The photodetector according to any one of (1) to (8), wherein the light guide section has a multilayer structure in which a plurality of layers each containing the plurality of structures and the medium are stacked, and the light absorption layer is provided on at least the outermost surface of the light guide section having the multilayer structure. (10) The photodetector according to (9), wherein the light guide section includes a first layer and a second layer stacked in order from the semiconductor substrate side as the plurality of layers, and the light absorption layer is further provided between the first layer and the second layer. (11) The photodetector according to (10), wherein the light absorption layer provided between the first layer and the second layer is embedded in the first layer. (12) The photodetector according to (10), wherein the light absorption layer provided between the first layer and the second layer is formed on the first layer. (13) The photodetector according to any one of (1) to (12), wherein the light absorption layer and the semiconductor substrate are electrically connected via a through-hole wiring.

[0220] This application claims priority based on Japanese Patent Application No. 2023-206958, filed on December 7, 2023, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0221] 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 semiconductor substrate having a first surface and a second surface facing each other, the semiconductor substrate having a pixel portion in which a plurality of pixels are arranged in an array, and a peripheral portion provided around the pixel portion; a light guiding portion provided on the first surface side of the semiconductor substrate, the light guiding portion including a plurality of structures each having a size equal to or smaller than the wavelength of incident light and a medium having a refractive index different from that of the plurality of structures, the medium being provided so as to fill the spaces between adjacent structures, the light guiding portion being provided across the pixel portion and the peripheral portion; a photoelectric conversion portion formed in the semiconductor substrate for each of the plurality of pixels, which photoelectrically converts light incident via the light guiding portion; a light absorbing layer provided in the peripheral portion on the surface of the light guiding portion opposite the semiconductor substrate; and a protective film covering the surface of the light absorbing layer.

2. The photodetector according to claim 1, wherein the light absorbing layer is made of a black color filter or a tungsten film.

3. The photodetector according to claim 2, wherein the black color filter comprises titanium oxide filler dispersed resin, carbon black pigment dispersed resin or organic pigment dispersed resin.

4. The optical detection device of claim 1, wherein the protective film comprises any one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, oxygen-doped silicon carbide, nitrogen-doped silicon carbide, aluminum oxide, hafnium oxide, tantalum oxide, and indium oxide.

5. The photodetector device according to claim 1, further comprising an on-chip lens layer between said light absorbing layer and said protective film.

6. The light detection device according to claim 1, wherein the protective film has an uneven structure above the light absorption layer.

7. The photodetector according to claim 1, wherein said protective film is a multi-layer interference film in which layers having different refractive indices are stacked.

8. The light detection device according to claim 1, wherein the protective film extends from the surface of the light absorption layer to the pixel portion.

9. The optical detection device according to claim 1, wherein the light guiding section has a multi-layer structure in which a plurality of layers each containing the plurality of structures and the medium are stacked, and the light absorption layer is provided on at least the outermost surface of the light guiding section having the multi-layer structure.

10. The optical detection device described in claim 9, wherein the light-guiding section includes a first layer and a second layer stacked in order from the semiconductor substrate side as the plurality of layers, and the optical absorption layer is further provided between the first layer and the second layer.

11. The optical detection device according to claim 10, wherein the light absorbing layer provided between the first layer and the second layer is embedded in the first layer.

12. The optical detection device according to claim 10, wherein the light absorbing layer provided between the first layer and the second layer is formed on the first layer.

13. The photodetector according to claim 1, wherein the light absorption layer and the semiconductor substrate are electrically connected via a through-wire.

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