Light detection device

Abstract

A light detection device according to an embodiment of the present disclosure comprises: a semiconductor substrate having a first surface and a second surface facing each other, and having an effective pixel region in which a plurality of pixels are arranged in an array and a peripheral pixel region provided around the effective pixel region; a light guide part including a plurality of structures each having a size equal to or less than the wavelength of the incident light and disposed in the effective pixel region and the peripheral pixel region, and a medium provided so as to fill the space between the plurality of adjacent structures and having a refractive index different from the refractive index of the plurality of structures, the light guide part being provided over the effective pixel region and the peripheral pixel region on a first surface side of the semiconductor substrate; and a photoelectric conversion part embedded in the semiconductor substrate in each of the plurality of pixels and photoelectrically converting light incident via the light guide part.

Description

Photodetector

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

[0002] For example, Patent Document 1 discloses a photodetector device that has a spectroscopic section including a structure configured to be able to disperse light incident on pixel Pg, and that improves the resolution of green (G) and the image quality by splitting the light in the spectroscopic section and propagating the light to adjacent pixels Pr and Pb.

[0003] Japanese Patent Application Laid-Open No. 2023-152522

[0004] Incidentally, there is a demand for improved device characteristics in photodetectors.

[0005] It would be desirable to provide a photodetector that allows for improved device performance.

[0006] An optical detection device according to one embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, and having an effective pixel region in which a plurality of pixels are arranged in an array, and a peripheral pixel region provided around the effective pixel region; a light guide portion provided on the first surface side of the semiconductor substrate across the effective pixel region and the peripheral pixel region, the light guide portion including a plurality of structures each having a size equal to or smaller than the wavelength of incident light and arranged in the effective pixel region and a medium having a refractive index different from that of the plurality of structures and provided so as to fill the spaces between adjacent structures; and 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.

[0007] In a photodetector according to an embodiment of the present disclosure, a plurality of structures each having a size equal to or smaller than the wavelength of incident light that constitute a light guide section provided across an effective pixel region and a peripheral pixel region on the first surface side of a semiconductor substrate are arranged in the effective pixel region as well as in a peripheral pixel region around the effective pixel region, thereby preventing deformation of the shapes of the plurality of structures arranged in the effective pixel region.

[0008] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the photodetector illustrated in FIG. 1. FIG. 3 is a plan view schematically illustrating an example of a configuration of an effective pixel region and a peripheral pixel region of the photodetector illustrated in FIG. 1. FIG. 4 is a diagram illustrating an example of a circuit configuration of a unit pixel of the photodetector illustrated in FIG. 1. FIG. 5A is a schematic view illustrating an example of a layout of a plurality of structures in the effective pixel region. FIG. 5B is a schematic view illustrating an example of a layout of a plurality of structures in the peripheral pixel region. FIG. 6A is a schematic view illustrating another example of a layout of a plurality of structures in the effective pixel region. FIG. 6B is a schematic view illustrating another example of a layout of a plurality of structures in the peripheral pixel region. FIG. 7A is a cross-sectional view schematically illustrating an example of a manufacturing process for the photodetector illustrated in FIG. 1. FIG. 7B is a cross-sectional view schematically illustrating a process subsequent to FIG. 7A. FIG. 7C is a cross-sectional view schematically illustrating a process subsequent to FIG. 7B. FIG. 7D is a cross-sectional view schematically illustrating a process subsequent to FIG. 7C. FIG. 7E is a cross-sectional view schematically illustrating a process subsequent to FIG. 7D. 7F is a schematic cross-sectional view showing a step subsequent to FIG. 7E. FIG. 7G is a schematic cross-sectional view showing a step subsequent to FIG. 7F. FIG. 7H is a schematic cross-sectional view showing a step subsequent to FIG. 7G. FIG. 7I is a schematic cross-sectional view showing a step subsequent to FIG. 7H. FIG. 7J is a schematic cross-sectional view showing a step subsequent to FIG. 7I. FIG. 7K is a schematic cross-sectional view showing a step subsequent to FIG. 7J. FIG. 7L is a schematic cross-sectional view showing a step subsequent to FIG. 7K. FIG. 8 is a schematic cross-sectional view showing an example of a configuration of a photodetector according to Modification 1 of the present disclosure. FIG. 9 is a schematic cross-sectional view showing an example of a configuration of a photodetector according to Modification 2 of the present disclosure. FIG. 10 is a schematic cross-sectional view showing an example of a configuration of a photodetector according to a second embodiment of the present disclosure. FIG. 11A is a schematic view showing an example of a layout (B) of color filters and multiple structures in each pixel of the effective pixel region of the photodetector shown in FIG. 10. FIG. 11B is a schematic view showing an example of a layout of multiple structures in each pixel of the peripheral pixel region of the photodetector shown in FIG. 10. Fig. 11C is a schematic diagram illustrating another example of the layout of a plurality of structures in each pixel in the peripheral pixel region of the photodetector shown in Fig. 10. Fig. 12 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 3 of the present disclosure.FIG. 13 is a cross-sectional schematic diagram illustrating an example of the configuration of a light detection device according to Modification 4 of the present disclosure. FIG. 14 is a functional block diagram illustrating an example of an electronic device (camera) using the light detection device shown in FIG. 1. FIG. 15A is a schematic diagram illustrating an example of the overall configuration of a light detection system using the light detection device shown in FIG. 1. FIG. 15B is a diagram illustrating an example of the circuit configuration of the light detection system shown in FIG. 15A. FIG. 16 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 17 is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 18 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 19 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 order of description is as follows: 1. First Embodiment (an example of a photodetector in which a plurality of structures constituting a light guide section are arranged in an effective pixel region and a peripheral pixel region) 2. Modifications 2-1. Modification 1 (another example of a photodetector configuration) 2-2. Modification 2 (another example of a photodetector configuration) 3. Second Embodiment (an example of a photodetector in which a single-layer color filter and a plurality of structures constituting a light guide section are arranged in the peripheral pixel region, and a color filter that absorbs the light is arranged at the end of the light dispersed by the plurality of structures) 4. Modifications 4-1. Modification 3 (another example of a photodetector configuration) 4-2. Modification 4 (another example of a photodetector configuration) 5. Application Examples 6. Application Examples

[0010] 1. First Embodiment FIG. 1 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 1) according to a first 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 configuration of an effective pixel region 100A and a peripheral pixel region 100B therearound 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 an effective pixel region (effective pixel region 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. 14 ), converts the amount of incident light imaged on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal as a pixel signal. The photodetector 1 has an effective pixel region 100A as an imaging area on a semiconductor substrate 11, and also has a peripheral pixel region 100B surrounding the effective pixel region 100A. The peripheral pixel region 100B has, for example, a pixel control unit 111, a signal processing unit 112, a control unit 113, and a processing unit 114. The photodetector 1 also has, for example, a plurality of control lines Lread and a plurality of signal lines VSL.

[0012] In the effective pixel region 100A, for example, a plurality of unit pixels P are two-dimensionally arranged 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 in the effective pixel area 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 lines VSL are signal lines capable of transmitting signals from the unit pixels P, and are connected to the unit pixels P in the effective pixel region 100A and the signal processing unit 112. In the effective pixel region 100A, for example, one or more signal lines VSL are wired for each pixel column made up of a plurality of unit pixels P lined up in the vertical direction (column direction). The signal lines VSL are configured to be able to transmit signals output from the unit pixels 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 in the effective pixel area 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 in the effective pixel area 100A via a control line Lread. The pixel control unit 111 is controlled by the control unit 113 and controls the unit pixels P in the effective pixel area 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 signals read out from the unit pixels P via the signal lines 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 in the effective pixel area 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 effective pixel area 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 integrally configured.

[0023] The effective pixel area 100A is an area where a subject image formed by the imaging lens is photoelectrically converted by a photodiode (PD) provided for each unit pixel P to generate a signal for generating an image. A first dummy pixel area that generates a pixel signal to assist in image generation may be provided on the periphery of the effective pixel area. Furthermore, a second dummy pixel area that does not generate a pixel signal may be provided outside the first dummy pixel area.

[0024] 3, the peripheral pixel region 100B has an optical black (OPB) region 100b that outputs a background signal and is provided on the periphery of the effective pixel region 100A. In the OPB region 100b, for example, similar to the effective pixel region 100A, a plurality of unit pixels P are two-dimensionally arranged in a matrix, and a photodiode (PD) is provided for each unit pixel P.

[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, a photoelectric conversion unit 12 and a readout circuit 31. The photoelectric conversion unit 12 is configured to receive light and generate a signal. The readout circuit 31 is configured to be able to output a signal based on charges photoelectrically converted. The readout circuit 31 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 31 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 31 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 31 may be configured to change the conversion efficiency (gain) when converting electric charge into voltage. For example, the readout circuit 31 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 31, 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 31 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 multiple unit pixels P are two-dimensionally arranged in a matrix in the effective pixel region 100A. Each of the multiple unit pixels 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 30 provided on the side opposite the light incident side S1 of the light receiving section 10. As described above, the photodetector 1 includes the effective pixel region 100A in which the multiple unit pixels P are two-dimensionally arranged in a matrix, and a peripheral pixel region 100B surrounding the effective pixel region 100A. The light receiving section 10, the optical layer 20, and the multilayer wiring layer 30 are provided, for example, across the effective pixel region 100A and the peripheral pixel region 100B. The optical layer 20 includes, for example, a light guide section 26 including multiple nanostructures 26A and a medium 26B filling the spaces between adjacent multiple structures 26A. In the photodetector 1, for example, as shown in FIG. 1, a plurality of structures 26A constituting the light guide section 26 are arranged in the effective pixel region 100A and the OPB region 100b of the peripheral pixel region 100B.

[0044] Here, light-guiding section 26 corresponds to a specific example of a "light-guiding section" in an embodiment of the present disclosure. Multiple structures 26A correspond to a specific example of a "multiple structures" in an embodiment of the present disclosure, and medium 26B corresponds to a specific example of a "medium" in an 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 corresponds to a specific example of a "semiconductor substrate" in an embodiment of the present disclosure and is made of, for example, a silicon substrate (Si). 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 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. A gate electrode, a gate insulating film, and the like are provided on the second surface 11S2 of the semiconductor substrate 11.

[0047] The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" in an embodiment of the present disclosure. 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. For example, one photoelectric conversion unit 12 is embedded in each unit pixel P.

[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, for example, in a grid pattern across the effective pixel region 100A and the surrounding OPB region 100b. 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 light-shielding film 21, a partition 22, a color filter 23, a spacer layer 24, a planarization layer 25, and a light-guiding section 26, and is configured to guide light incident from the light incident side S1 to the light-receiving section 10 side.

[0053] The light-shielding film 21 is provided, for example, between adjacent unit pixels P in the effective pixel region 100A, and continuously in the OPB region in the peripheral pixel region 100B. In the effective pixel region 100A, the light-shielding film 21 prevents light obliquely incident from the light incident side S1 from leaking into adjacent unit pixels P, and is provided, for example, in a lattice pattern. In the peripheral pixel region 100B, the light-shielding film 21 blocks light incident on the photoelectric conversion unit 12 provided in the OPB region 100b. In the effective pixel region, the light-shielding film 21 is provided between the light-receiving unit 10 (specifically, the dielectric layer 14) and the partition wall 22, and in the peripheral pixel region 100B, the light-shielding film 21 is provided between the partition wall 22 and the color filter 23. The light-shielding film 21 can be formed using, for example, tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), or an alloy thereof.

[0054] The partition 22 is a frame body provided at the boundary between adjacent unit pixels P and having an opening 22H for each unit pixel P. In other words, the partition 22 is provided so as to surround the unit pixel P, similar to the isolation portion 13 and the light-shielding film 21 provided in the effective pixel region 100A, and is provided in a grid pattern in the effective pixel region 100A, for example.

[0055] The partition wall 22 is intended to prevent light obliquely incident from the light incident side S1 from leaking into an adjacent unit pixel P. The partition wall 22 is made of, for example, a material having a lower refractive index than the color filter 23.

[0056] The partition 22 may also serve as a light shield for the unit pixel P, which determines the optical black level. The partition 22 may also serve as a light shield to suppress noise generation in peripheral circuits provided in the peripheral pixel region 100B. In this case, the above-described light-shielding film 21 can be omitted. When the partition 22 also serves as the light-shielding film 21, the partition 22 is 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 of materials for forming the partition 22 include metal compounds such as TiN. The partition 22 may be formed, for example, as a single-layer film or a laminated film. When a laminated film is used, a layer made of, for example, Ti, tantalum (Ta), W, cobalt (Co), molybdenum (Mo), or alloys, nitrides, oxides, or carbides thereof may be provided as an underlayer.

[0057] The color filters 23 selectively transmit light of a predetermined wavelength, and include, for example, a red filter 23R that selectively transmits red light (R), a green filter 23G that selectively transmits green light (G), and a blue filter 23B that selectively transmits blue light (B). The color filters 23R, 23G, and 23B are provided across the effective pixel area 100A and the surrounding OPB area 100b.

[0058] In the effective pixel region 100A, the color filters 23R, 23G, and 23B are formed by filling the openings 22H of the partition walls 22 with a resin material in which a desired pigment or dye is dispersed. For example, for four unit pixels P arranged in two rows and two columns, the color filters 23R, 23G, and 23B are arranged such that two green filters 23G are arranged on a diagonal line and one red filter 23R and one blue filter 23B are arranged on each of the orthogonal diagonal lines. In the unit pixels P provided with the color filters 23R, 23G, and 23B, for example, the corresponding color light is selectively photoelectrically converted in the respective photoelectric conversion units 12.

[0059] That is, in the effective pixel area 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.

[0060] The color filters 23 may include complementary color filters that selectively transmit cyan (C), magenta (M), and yellow (Y) in addition to the red filter 23R, green filter 23G, and blue filter 23B. Furthermore, the color filters 23 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 23 may include a filter that selectively transmits infrared light.

[0061] The thickness of the color filter 23 may be different for each color, taking into consideration the color reproducibility and sensor sensitivity of the optical spectrum.

[0062] In the OPB region 100b, the red filters 23R and green filters 23G of the color filters 23R, 23G, and 23B are arranged in parallel, alternating in the row and column directions for each unit pixel P. The blue filters 23B are stacked on the red filters 23R and green filters 23G, and are provided so as to cover the side surfaces of the red filters 23R and green filters 23G arranged on the periphery of the OPB region 100b. Note that the above structure is an example and is not limited to this.

[0063] The spacer layer 24 is provided between the light receiving section 10 and the light guiding section 26. The spacer layer 24 is formed across the effective pixel region 100A and the peripheral pixel region 100B so as to be stacked on, for example, the partition walls 22 and the color filters 23 provided in the effective pixel region 100A and the color filters 23 provided in the OPB region 100b. The spacer layer 24 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), or the like.

[0064] The spacer layer 24 may be formed using a low refractive index material other than the insulating material, or may be formed using another material that transmits light in the wavelength range to be measured. The spacer layer 24 can also be referred to as a transparent layer that transmits light. The thickness of the spacer layer 24 is, for example, 2 μm or more and 3 μm or less.

[0065] 7D , the planarization layer 25 is intended to fill in the steps of the spacer layer 24 that are generated in the peripheral pixel region 100B when the spacer layer 24 is provided so as to cover the stacked color filters 23, thereby planarizing the surface. The planarization layer 25 can be formed using, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (AlO), or the like.

[0066] The light guide unit 26 is configured as, for example, a light guide element capable of guiding light by imparting a phase delay to incident light. The light guide unit 26 is a light guide element that utilizes metamaterial (metasurface) technology. The light guide unit 26 can also be referred to as a metasurface layer (or metamaterial layer). For example, as shown in FIG. 1 , the light guide unit 26 is provided across the effective pixel region 100A and the peripheral pixel region 100B.

[0067] The light guide 26 has a plurality of structures 26A and a medium 26B provided around the plurality of structures 26A. The light guide 26 uses the plurality of structures 26A, 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 guide 26. For example, light that has passed through an optical system such as an imaging lens is incident on the plurality of structures 26A. The plurality of structures 26A 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 26A may also have a size equal to or smaller than the wavelength range of infrared light.

[0068] Each of the multiple structures 26A is, for example, a columnar (pillar-shaped) structure, and can be referred to as a nanopillar. The multiple structures 26A can be referred to as a metasurface element. As an example, the multiple structures 26A have a cylindrical shape. The multiple structures 26A are arranged side by side in the X-axis direction or the Y-axis direction, with the medium 26B sandwiched therebetween.

[0069] The shape of the plurality of structures 26A 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 another shape (e.g., a freeform shape).

[0070] The multiple structures 26A are also referred to as metaatoms, nanoatoms, nanoposts, metasurface structures, microstructures, etc.

[0071] The medium 26B is provided so as to fill the periphery of the plurality of structures 26A. The plurality of structures 26A are provided within the medium 26B, and can be said to be arranged by replacing part of the medium 26B. The medium 26B can also be said to be a medium layer or a protective layer (protective member).

[0072] In the light-guiding section 26, a plurality of structures 26A are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 26A 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 26A may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0073] The plurality of structures 26A have a refractive index that is different from the refractive index of the surrounding medium 26B. For example, the plurality of structures 26A have a refractive index that is higher than the refractive index of the medium 26B.

[0074] Examples of materials that can be used to form the structures 26A include titanium oxide (TiO), silicon, polysilicon (Poly-Si), amorphous silicon (a-Si), and germanium (Ge).

[0075] The plurality of structures 26A may be formed using titanium (Ti), hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), indium (In), niobium (Nb), or the like, or an oxide, nitride, oxynitride, or composite thereof. The plurality of structures 26A may be formed by including other metal compounds (metal oxides, metal nitrides, etc.).

[0076] The plurality of structures 26A may be formed using GaP, GaN, GaAs, SiC, etc. The plurality of structures 26A 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 26A may be formed using different materials.

[0077] The medium 26B is made of, for example, an inorganic material such as an oxide, a nitride, or an oxynitride. The medium 26B 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 26B may also be made of TEOS.

[0078] The medium 26B may be formed using a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The medium 26B may be made of a material in which any of these resins contains fluorine. The medium 26B 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 26A and the medium 26B 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 26A and the medium 26B may be formed using air. For example, the plurality of structures 26A may be formed to include air (voids).

[0080] The light-guiding unit 26 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 26A and the medium surrounding them. The light-guiding unit 26 can adjust the propagation direction of the light by, for example, imparting a phase delay to the incident light using the plurality of structures 26A and the medium 26B.

[0081] The materials of the plurality of structures 26A and the medium 26B (optical constants of each material), the size (width (diameter), height, etc.) and pitch (arrangement interval) of the plurality of structures 26A, etc. are determined so that light of a desired wavelength range among the 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 26A and the medium 26B can be set.

[0082] As an example, in the photodetector 1, the material, size, arrangement number, etc. of the plurality of structures 26A 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 26A 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 26 may be configured as, for example, a spectroscopic unit (spectroscopic element) capable of separating incident light. The optical layer 20 (or the light guide 26) 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 26) may also be referred to as an optical element configured to redirect light.

[0084] In the present embodiment, the plurality of structures 26A are arranged across the effective pixel region 100A and the OPB region 100b, as shown in FIG. 1 . FIG. 5A shows an example of the layout of the plurality of structures 26A arranged in each unit pixel P (red pixel Pr, green pixel Pg, and blue pixel Pb) in the effective pixel region 100A. FIG. 5B shows an example of the layout of the plurality of structures 26A arranged in each unit pixel P in the OPB region 100b. As shown in FIGS. 5A and 5B , the plurality of structures 26A arranged in the OPB region 100b are arranged in the same layout as the plurality of structures 26A arranged in the effective pixel region 100A. By arranging the plurality of structures 26A in the OPB region 100b in this manner, deformation of the shapes of the plurality of structures 26A arranged in the effective pixel region 100A is prevented during the manufacturing process, and the plurality of structures 26A having a uniform shape is formed across the entire effective pixel region 100A. In addition, the plurality of structures 26A arranged in the OPB region 100b reduce flare caused by surface reflection in the light guiding section 26 extending into the peripheral pixel region 100B.

[0085] 6A shows another example of the layout of the plurality of structures 26A arranged in each unit pixel P (red pixel Pr, green pixel Pg, and blue pixel Pb) in the effective pixel region 100A. FIG. 6B shows another example of the layout of the plurality of structures 26A arranged in each unit pixel P in the OPB region 100b. As shown in FIG. 6A , the plurality of structures 26A arranged in each unit pixel P (red pixel Pr, green pixel Pg, and blue pixel Pb) in the effective pixel region 100A are freeform columnar structures in a planar view, while the plurality of structures 26A arranged in the OPB region 100b are circular columnar structures having the same diameter in a planar view. In this way, the plurality of structures 26A arranged in the OPB region 100b may have a different layout from the plurality of structures 26A arranged in the effective pixel region 100A.

[0086] 1, the plurality of structures 26A arranged in the OPB region 100b may be arranged to extend outside the OPB region 100b. The plurality of structures 26A arranged outside the OPB region 100b propagate the incident light L toward the OPB region 100b. This further reduces flare caused by surface reflection in the light-guiding section 26 extending into the peripheral pixel region 100B.

[0087] 1, the plurality of structures 26A arranged above the unit pixels P arranged in the vicinity of the effective pixel region 100A (for example, the unit pixels P adjacent to the effective pixel region 100A in the OPB region 100b) may be configured to propagate incident light L to the unit pixels P arranged in the adjacent effective pixel region 100A. This improves the output of the unit pixels P arranged on the periphery of the effective pixel region 100A.

[0088] The multilayer wiring layer 30 is stacked on the second surface 11S2 side of the semiconductor substrate 11. The multilayer wiring layer 30 includes, for example, a conductor film and an insulating film, and has a plurality of wirings, vias, etc. The multilayer wiring layer 30 has a configuration in which a plurality of wirings are stacked with an insulating film interposed therebetween as an interlayer insulating film. The multilayer wiring layer 30 includes, for example, two or three or more layers of wirings.

[0089] The wiring of the multilayer wiring layer 30 is formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring of the multilayer wiring layer 30 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).

[0090] The semiconductor substrate 11 and the multilayer wiring layer 30 are provided with the above-described readout circuit 31, for example, for each unit pixel P or for each plurality of unit pixels P. In addition to the above-described readout circuit 31, the multilayer wiring layer 30 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.

[0091] [Method of Manufacturing Photodetector] FIGS. 7A to 7L show the steps of a method of manufacturing the photodetector 1 in order of process.

[0092] 7A, the light-shielding film 21, the partition walls 22, and the color filters 23 (color filters 23R, 23G, and 23B) are formed on the first surface 11S1 of the semiconductor substrate 11. Next, as shown in FIG. 7B, the spacer layer 24 is formed by, for example, chemical vapor deposition (CVD).

[0093] 7C, a planarization layer 25 is formed on the spacer layer 24 by, for example, CVD. Next, as shown in Fig. 7D, the surface of the planarization layer 25 is planarized by, for example, chemical mechanical polishing (CMP). Next, as shown in Fig. 7E, a medium 26B made of a low refractive index material (for example, SiN / TEOS) is formed on the planarization layer 25.

[0094] Next, as shown in Fig. 7E, a medium 26B made of a low refractive index material (e.g., SiN / TEOS) is formed on the planarization layer 25. Subsequently, as shown in Fig. 7F, a hard mask 41 is formed on the medium 26B. Next, as shown in Fig. 7G, a hard mask 42 is patterned on the hard mask 41 using photolithography.

[0095] 7H, the hard mask 41 is processed by, for example, dry etching to form an opening 41H. Next, as shown in FIG. 7I, the medium 26B is processed to form an opening 26H. Then, as shown in FIG. 7J, the hard mask 41 is removed by, for example, wet etching.

[0096] Next, as shown in FIG. 7K, a high refractive index material (e.g., TiO ２ ) is embedded in opening 26H. Next, as shown in FIG. 7L, the high refractive index film formed on medium 26B is removed using, for example, CMP. This forms light guide 26 in which multiple structures 26A are embedded in medium 26B. This completes the photodetector shown in FIG. 1.

[0097] The above-described manufacturing method is merely an example, and other manufacturing methods may be adopted.

[0098] [Functions and Effects] In the photodetector 1 of this embodiment, a light guide section 26 is provided on the first surface 11S1 side, which is the light incident side S1 of the semiconductor substrate 11, in which a plurality of structures 26A are arranged in the OPB region 100b of the effective pixel region 100A and the peripheral pixel region 100B. Each of the plurality of structures 26A has a size equal to or smaller than the wavelength of the incident light, and a medium 26B having a refractive index different from that of the plurality of structures 26A is filled between adjacent structures 26A. This prevents the shape of the plurality of structures 26A arranged in the effective pixel region 100A from being distorted. This is described below.

[0099] 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.

[0100] 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.

[0101] However, when the medium containing the nanopost structures extends outside the effective pixel area, the difference in the density of the nanopost structures within the medium between the effective pixel area and the area outside it tends to cause defects in the formation of the nanopost structures located near the edge of the effective pixel area, which leads to deterioration of the device characteristics.

[0102] In contrast to this, in the present embodiment, the plurality of structures 26A arranged in the effective pixel region 100A are provided in the peripheral pixel region 100B, for example, up to the OPB region 100b, thereby preventing the shape of the plurality of structures 26A in the effective pixel region 100A from being distorted.

[0103] As a result, in the photodetector 1 of this embodiment, a plurality of structures 26A having a uniform shape are formed over the entire effective pixel region 100A, thereby making it possible to improve the device characteristics.

[0104] Furthermore, if the medium containing the nanopost structures is extended outside the effective pixel region, there is a concern that flare may worsen due to reflection on the medium surface. In contrast, in the photodetector 1 of this embodiment, the multiple structures 26A are arranged even outside the OPB region 100b. This reduces flare due to surface reflection on the light-guiding section 26 extending into the peripheral pixel region 100B. This makes it possible to further improve the device characteristics.

[0105] Furthermore, in the photodetector 1 of this embodiment, the multiple structures 26A arranged above the unit pixels P adjacent to the effective pixel region 100A in the OPB region 100b are configured to propagate incident light to the unit pixels P arranged in the adjacent effective pixel region 100A. This improves the output of the unit pixels P arranged on the periphery of the effective pixel region 100A. This makes it possible to further improve the device characteristics.

[0106] Next, a first embodiment of the present disclosure, modifications 1 to 4, and application examples will be described. In the following, the same components as those in the above embodiment will be assigned the same reference numerals, and their description will be omitted as appropriate.

[0107] 8 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 first embodiment.

[0108] In the first embodiment, an example was shown in which the light-guiding section 26 penetrates the medium 26B in the thickness direction (Z-axis direction), and both ends of the plurality of structures 26A form the same plane as the medium 26B, but this is not limited to this. In the photodetector 1A of this modified example, the plurality of structures 26A penetrating the medium 26B in the Z-axis direction further penetrate the planarization layer 25 and extend into the spacer layer 24. Except for this point, the photodetector 1A has substantially the same configuration as the photodetector 1 of the first embodiment.

[0109] In this manner, in this modification, the plurality of structures 26A are extended into the spacer layer 24. This suppresses misalignment of the plurality of structures 26A with respect to each unit pixel P. In addition, peeling of the light guide section 26 can be prevented. This makes it possible to improve reliability.

[0110] 9 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 first embodiment.

[0111] The photodetector 1B of this modification is configured such that a plurality of structures 26A arranged in the OPB region 100b propagate incident light in a predetermined direction. Except for this point, the photodetector 1B has substantially the same configuration as the photodetector 1 of the first embodiment.

[0112] As an example, in this modification, the plurality of structures 26A arranged in the OPB region 100b separate incident light into red light (R) and green light (G) and blue light (B), as shown in Fig. 9. The separated red light (R) is propagated to a region in which the green filter 23G and the blue filter 23B arranged in the OPB region 100b are stacked, and the green light (G) and blue light (B) are propagated to a region in which the red filter 23R and the blue filter 23B arranged in the OPB region 100b are stacked.

[0113] In this manner, in this modification, the multiple structures 26A arranged in the OPB region 100b are configured to propagate incident light in a predetermined direction. This reduces the generation of stray light due to reflection near the first surface 11S1 of the semiconductor substrate 11. Therefore, it is possible to further improve the device characteristics compared to the photodetector 1 of the first embodiment.

[0114] 10 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 2) according to a second embodiment of the present disclosure. The photodetector 2 is applicable to, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and has an effective pixel region 100A as an imaging area in which a plurality of pixels are two-dimensionally arranged in a matrix. The photodetector 2 is, for example, a so-called back-illuminated photodetector in this CMOS image sensor.

[0115] [Configuration of the Photodetector] As described above, the photodetector 2 is a back-illuminated imaging device. The multiple unit pixels P are two-dimensionally arranged in a matrix in the effective pixel region 100A. Each of the multiple unit pixels P includes, for example, a stack of a light receiving section 50, an optical layer 60 provided on the light incident side S1 of the light receiving section 50, and a multilayer wiring layer 70 provided on the side opposite the light incident side S1 of the light receiving section 50. As described above, the photodetector 2 includes the effective pixel region 100A in which the multiple unit pixels P are two-dimensionally arranged in a matrix, and a peripheral pixel region 100B surrounding the effective pixel region 100A. The light receiving section 50, the optical layer 60, and the multilayer wiring layer 70 are provided, for example, across the effective pixel region 100A and the peripheral pixel region 100B. The optical layer 60 includes, for example, a light guide section 66 including multiple nanostructures 66A and a medium 66B filling the spaces between adjacent multiple structures 66A. 10 , in the photodetector 2, a plurality of structures 66A constituting the light guide section 66 are arranged in the effective pixel region 100A and the peripheral pixel region 100B, for example, in the OPB region 100b. Furthermore, the optical layer 60 has color filters 63 that selectively transmit light of a predetermined wavelength below the light guide section 66 in the effective pixel region 100A and the peripheral pixel region 100B, for example, in the OPB region 100b. In the OPB region 100b, the color filters 63 that absorb light of a predetermined wavelength separated into the plurality of structures 66A are arranged in the propagation direction of the light.

[0116] Here, the light guide portion 66 corresponds to a specific example of a "light guide portion" in an embodiment of the present disclosure. The plurality of structures 66A corresponds to a specific example of a "plurality of structures" in an embodiment of the present disclosure, and the medium 66B corresponds to a specific example of a "medium" in an embodiment of the present disclosure. The color filter 63 corresponds to a specific example of a "color filter" in an embodiment of the present disclosure.

[0117] The light receiving unit 50 includes a semiconductor substrate 51 having a first surface 51S1 and a second surface 51S2 facing each other, and a plurality of photoelectric conversion units 52 embedded in the semiconductor substrate 51. The light receiving unit 50 further includes a separation unit 53.

[0118] The semiconductor substrate 51 corresponds to a specific example of a "semiconductor substrate" in an embodiment of the present disclosure and is made of, for example, Si. The semiconductor substrate 51 may be an SOI substrate, a SiGe substrate, a SiC substrate, or the like. The semiconductor substrate 51 may be made of a III-V compound semiconductor material, or may be formed using other semiconductor materials. A first surface 51S1 of the semiconductor substrate 51 is a light-receiving surface (light incident surface). A second surface 51S2 of the semiconductor substrate 51 is an element formation surface on which elements such as transistors are formed. A gate electrode, a gate insulating film, and the like are provided on the second surface 51S2 of the semiconductor substrate 51.

[0119] The photoelectric conversion unit 52 corresponds to a specific example of a "photoelectric conversion unit" in an embodiment of the present disclosure. The photoelectric conversion unit 52 is, for example, a PIN-type photodiode (PD), and has a pn junction in a predetermined region of the semiconductor substrate 51. For example, one photoelectric conversion unit 52 is embedded in each unit pixel P.

[0120] The separation portions 53 are provided between adjacent unit pixels P. In other words, the separation portions 53 are provided so as to surround the unit pixels P, and are provided, for example, in a grid pattern across the effective pixel region 100A and the surrounding OPB region 100b. The separation portions 53 electrically and optically separate adjacent unit pixels P, and extend, for example, from the first surface 51S1 side of the semiconductor substrate 51 toward the second surface 51S2 side.

[0121] The isolation portion 53 can be formed by diffusing p-type impurities, for example. Alternatively, the isolation portion 53 may have an STI structure or an FFTI structure in which an opening is formed in the semiconductor substrate 51 from the first surface 51S1 side and an insulating film is buried in the opening. An air gap may be formed in the STI structure or the FFTI structure.

[0122] A dielectric layer 54, which also serves to prevent reflection on the first surface 51S1 of the semiconductor substrate 51, is provided on the first surface 51S1 of the semiconductor substrate 51. The dielectric layer 54 may be, for example, a film having a positive fixed charge or a film having a negative fixed charge.

[0123] The dielectric layer 54 may be made of a semiconductor material or a conductive material having a band gap wider than the band gap of the semiconductor substrate 51. Specifically, for example, HfO ｘ , AlO ｘ , ZrO ｘ , TaO ｘ , TiO ｘ , LaO ｘ , PrO ｘ , CeO ｘ , NdO ｘ , PmO ｘ , SmO ｘ , EuO ｘ , GdO ｘ , TbO ｘ , DyO ｘ , HoO ｘ , TmO ｘ , YbO ｘ , LuO ｘ , Y.O. ｘ , HfN ｘ , AlN ｘ , HfO ｘ N ｙ and AlO ｘ N ｙ The dielectric layer 54 may be a single layer film or a laminated film made of different materials.

[0124] The optical layer 60 includes, for example, a light-shielding film 61, a partition 62, a color filter 63, a spacer layer 64, a planarization layer 65, and a light-guiding section 66, and is configured to guide light incident from the light incident side S1 to the light-receiving section 50 side.

[0125] The light-shielding film 61 is provided, for example, between adjacent unit pixels P in the effective pixel region 100A, and is provided continuously in the OPB region in the peripheral pixel region 100B. In the effective pixel region 100A, the light-shielding film 61 prevents light obliquely incident from the light incident side S1 from leaking into adjacent unit pixels P, and is provided, for example, in a lattice pattern. In the peripheral pixel region 100B, the light-shielding film 61 blocks light incident on the photoelectric conversion unit 52 provided in the OPB region 100b. In the effective pixel region, the light-shielding film 61 is provided between the light-receiving unit 50 (specifically, the dielectric layer 54) and the partition wall 62, and in the peripheral pixel region 100B, the light-shielding film 61 is provided between the partition wall 62 and the color filter 63. The light-shielding film 61 can be formed using, for example, W, Ag, Cu, Ti, Al, or an alloy thereof.

[0126] The partition 62 is a frame body provided at the boundary between adjacent unit pixels P and having an opening 62H for each unit pixel P. In other words, the partition 62 is provided so as to surround the unit pixel P, similar to the isolation portion 53 and the light-shielding film 61 provided in the effective pixel region 100A, and is provided in a grid pattern in the effective pixel region 100A, for example.

[0127] The partition wall 62 is intended to prevent light obliquely incident from the light incident side S1 from leaking into an adjacent unit pixel P. The partition wall 62 is made of, for example, a material having a lower refractive index than the color filter 63.

[0128] The partition 62 may also serve as a light shield for the unit pixel P, which determines the optical black level. The partition 62 may also serve as a light shield to suppress noise generation in peripheral circuits provided in the peripheral pixel region 100B. In this case, the above-described light-shielding film 61 can be omitted. When the partition 62 also serves as the light-shielding film 61, the partition 62 is formed using, for example, a material having light-shielding properties. Examples of such materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for forming the partition 62 include metal compounds such as TiN. The partition 62 may be configured as, for example, a single-layer film or a laminated film. When the partition 62 is configured as a laminated film, a layer made of, for example, Ti, Ta, W, Co, or Mo, or an alloy, nitride, oxide, or carbide thereof, may be provided as an underlayer.

[0129] The color filters 63 selectively transmit light of a predetermined wavelength, and include, for example, a red filter 63R that selectively transmits red light (R), a green filter 63G that selectively transmits green light (G), and a blue filter 63B that selectively transmits blue light (B). The color filters 63R, 63G, and 63B are provided across the effective pixel area 100A and the surrounding OPB area 100b.

[0130] In the effective pixel region 100A, each of the color filters 63R, 63G, and 63B is formed by filling an opening 62H of the partition wall 62 with a resin material in which a desired pigment or dye is dispersed. For example, for four unit pixels P arranged in two rows and two columns, each of the color filters 63R, 63G, and 63B has two green filters 63G arranged diagonally, and one red filter 63R and one blue filter 63B arranged on each of the orthogonal diagonals. In each unit pixel P provided with each of the color filters 63R, 63G, and 63B, the corresponding color light is selectively photoelectrically converted in the corresponding photoelectric conversion unit 52, for example.

[0131] That is, in the effective pixel area 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, as shown in FIG. 11A . 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 2 to obtain RGB pixel signals.

[0132] The color filter 63 may include complementary color filters that selectively transmit cyan (C), magenta (M), and yellow (Y) in addition to the red filter 63R, green filter 63G, and blue filter 63B. Furthermore, the color filter 63 may include a filter corresponding to white (W), that is, a filter that transmits light of all wavelengths incident on the photodetector 2. In addition, the color filter 63 may include a filter that selectively transmits infrared light.

[0133] The thickness of the color filter 63 may be different for each color, taking into consideration the color reproducibility and sensor sensitivity of the optical spectrum.

[0134] In the OPB region 100b, although the layout of each color filter 63R, 63G, 63B is different, similarly to the effective pixel region 100A, for example, for four unit pixels P arranged in 2 rows and 2 columns, two green filters 63G are arranged diagonally, and one red filter 63R and one blue filter 63B are arranged on each of the orthogonal diagonals, for example, in a Bayer pattern as shown in FIG. 11B.

[0135] The layout of the color filters 63R, 63G, and 63B disposed in the effective pixel area 100A and the OPB area 100b, respectively, will be described later together with the layout of the plurality of structures 66A that form the light guide section 66.

[0136] The spacer layer 64 is provided between the light receiving section 50 and the light guiding section 66. The spacer layer 64 is formed across the effective pixel region 100A and the peripheral pixel region 100B so as to be stacked on, for example, the partition walls 62 and the color filters 63 provided in the effective pixel region 100A and the color filters 63 provided in the OPB region 100b. The spacer layer 64 can be formed using, for example, SiO, SiN, AlO, etc.

[0137] The spacer layer 64 may be formed using a low refractive index material other than the insulating material, or may be formed using another material that transmits light in the wavelength range to be measured. The spacer layer 64 can also be called a transparent layer that transmits light. The thickness of the spacer layer 64 is, for example, 2 μm or more and 3 μm or less.

[0138] As described above, the planarization layer 65 is provided in the peripheral pixel region 100B to fill in the steps of the spacer layer 64 that are generated when the spacer layer 64 is provided so as to cover the stacked color filters 63, thereby planarizing the surface. The planarization layer 65 can be formed using, for example, SiO, SiN, AlO, etc.

[0139] The light guide unit 66 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 66 is a light guide element that utilizes metamaterial (metasurface) technology. The light guide unit 66 can also be referred to as a metasurface layer (or metamaterial layer). For example, as shown in FIG. 10 , the light guide unit 66 is provided across the effective pixel region 100A and the peripheral pixel region 100B.

[0140] The light guiding unit 66 has a plurality of structures 66A and a medium 66B provided around the plurality of structures 66A. The light guiding unit 66 uses the plurality of structures 66A, which are nanostructures, to propagate light toward the photoelectric conversion unit 52. Light from a subject, which is the object to be measured, is incident on the light guiding unit 66. For example, light that has passed through an optical system such as an imaging lens is incident on the plurality of structures 66A. The plurality of structures 66A 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 66A may also have a size equal to or smaller than the wavelength range of infrared light.

[0141] Each of the multiple structures 66A is, for example, a columnar (pillar-shaped) structure, and can be referred to as a nanopillar. The multiple structures 66A can be referred to as a metasurface element. As an example, the multiple structures 66A have a cylindrical shape. The multiple structures 66A are arranged side by side in the X-axis direction or the Y-axis direction, with the medium 66B sandwiched therebetween.

[0142] The shape of the plurality of structures 66A can be changed as appropriate, and may be a circle or a square in a plan view, or may be an ellipse, a polygon, a cross, or another shape (for example, a freeform shape).

[0143] The multiple structures 66A are also referred to as metaatoms, nanoatoms, nanoposts, metasurface structures, microstructures, etc.

[0144] The medium 66B is provided so as to fill the periphery of the plurality of structures 66A. The plurality of structures 66A are provided within the medium 66B, and can be said to be arranged by replacing part of the medium 66B. The medium 66B can also be said to be a medium layer or a protective layer (protective member).

[0145] In the light-guiding section 66, a plurality of structures 66A are arranged at intervals equal to or less than a predetermined wavelength of incident light. As an example, the plurality of structures 66A 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 66A may be arranged at intervals equal to or less than the wavelength range of infrared light.

[0146] The structures 66A have a refractive index that is different from the refractive index of the surrounding medium 66B. For example, the structures 66A have a refractive index that is higher than the refractive index of the medium 66B.

[0147] Examples of materials that can be used to form the structures 66A include TiO, silicon, Poly-Si, a-Si, and Ge.

[0148] The plurality of structures 66A may be formed using a single element such as Ti, Hf, Zr, Al, Ta, In, or Nb, or an oxide, nitride, or oxynitride thereof, or a composite thereof. The plurality of structures 66A may be formed by including other metal compounds (metal oxides, metal nitrides, etc.).

[0149] The plurality of structures 66A may be formed using GaP, GaN, GaAs, SiC, etc. The plurality of structures 66A may be formed using SiO, SiN, SiON, SiC, SiOC, or other silicon compounds. The plurality of structures 66A may be configured using different materials.

[0150] The medium 66B is made of, for example, an inorganic material such as an oxide, a nitride, or an oxynitride. The medium 66B may also be made of, for example, SiO, SiN, SiON, SiC, SiOC, or other silicon compounds. The medium 66B may also be made of TEOS.

[0151] The medium 66B may be formed using a siloxane-based resin, a styrene-based resin, an acrylic-based resin, or the like. The medium 66B may be made of a material in which any of these resins contains fluorine. The medium 66B 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.

[0152] The materials of the plurality of structures 66A and the medium 66B 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 66A and the medium 66B may be formed using air. For example, the plurality of structures 66A may be formed to include air (voids).

[0153] The light-guiding unit 66 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 66A and the medium surrounding them. The light-guiding unit 66 can adjust the propagation direction of the light by, for example, imparting a phase delay to the incident light using the plurality of structures 66A and the medium 66B.

[0154] The materials of the plurality of structures 66A and the medium 66B (optical constants of each material), the size (width (diameter), height, etc.) and pitch (arrangement interval) of the plurality of structures 66A, etc. are determined so that light of a desired wavelength range among the 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 66A and the medium 66B can be set.

[0155] As an example, in the photodetector 2, the material, size, arrangement number, etc. of the multiple structures 66A in each unit pixel P are determined so that light in a specific wavelength band to be detected travels to the photoelectric conversion unit 52 of the desired unit pixel P. For example, the multiple structures 66A 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.

[0156] The light guide 66 may be configured as, for example, a spectroscopic unit (spectroscopic element) capable of separating incident light. The optical layer 60 (or the light guide 66) may also be referred to as a splitter (color splitter). The optical layer 60 may also be referred to as a color splitter layer or a wavelength separation layer. The optical layer 60 (or the light guide 66) may also be referred to as an optical element configured to redirect light.

[0157] In this embodiment, the color filter 63 and the plurality of structural bodies 66A are arranged across the effective pixel region 100A and the OPB region 100b, as shown in Fig. 10 . Fig. 11A shows an example of the layout of the color filters 63R, 63G, and 63B and the plurality of structural bodies 66A arranged in each unit pixel P (red pixel Pr, green pixel Pg, and blue pixel Pb) in the effective pixel region 100A. Fig. 11B shows an example of the layout of the color filters 63R, 63G, and 63B and the plurality of structural bodies 66A arranged in each unit pixel P in the OPB region 100b. Fig. 11C shows another example of the layout of the color filters 63R, 63G, and 63B and the plurality of structural bodies 66A arranged in each unit pixel P in the OPB region 100b.

[0158] Each unit pixel P arranged in the effective pixel region 100A and the OPB region 100b is provided with a color filter 63 and a plurality of structural bodies 66A corresponding to red light (R), green light (G), or blue light (B). In Figures 11A to 11C, in order to distinguish the color filter 63 and the plurality of structural bodies 66A arranged in each unit pixel P from one another, an identification number (1, 2, 3, 4) is added to the end of the reference numeral for the color filter 63 and the plurality of structural bodies 66A of each unit pixel P. Identification number 1 corresponds to blue light (B), identification numbers 2 and 3 correspond to green light (G), and identification number 4 corresponds to red light (R).

[0159] For example, in the four unit pixels P arranged in two rows and two columns in the lower left corner shown in Figure 11A, the multiple structures 66A (multiple structures 664) arranged in the red pixel Pr propagate, of the incident light, red light (R) to the color filter 63 (red filter 634) and photoelectric conversion unit 12 of that pixel, green light (G) to the color filter 63 (green filters 632, 633) and photoelectric conversion unit 12 of the green pixel Pg, and blue light (B) to the color filter 63 (blue filter 631) and photoelectric conversion unit 12 of the blue pixel Pb. The multiple structures 66A (multiple structures 662 or multiple structures 663) arranged in the green pixel Pg propagate, of the incident light, green light (G) to the color filter 63 (green filter 632 or green filter 633) and photoelectric conversion unit 12 of that pixel, red light (R) to the color filter 63 (red filter 634) and photoelectric conversion unit 12 of the red pixel Pr, and blue light (B) to the color filter 63 (blue filter 631) and photoelectric conversion unit 12 of the blue pixel Pb. The plurality of structures 66A (plurality of structures 661) arranged in the blue pixel Pb propagate, of the incident light, blue light (B) to the color filter 63 (blue filter 631) and photoelectric conversion unit 12 of that pixel, green light (G) to the color filter 63 (green filters 632, 633) of the green pixel Pg and photoelectric conversion unit 12, and red light (R) to the color filter 63 (red filter 634) of the red pixel Pr and photoelectric conversion unit 12. In other words, in the effective pixel region 100A, color filters 63 that transmit light of a predetermined wavelength separated into the plurality of structures 66A are arranged.

[0160] 11B , for example, a green filter 632 is arranged in the unit pixel P having a plurality of structures 661, a blue filter 631 is arranged in the unit pixel P having a plurality of structures 662, a red filter 634 is arranged in the unit pixel P having a plurality of structures 623, and a green filter 633 is arranged in the unit pixel P having a plurality of structures 664. In other words, in the OPB region 100b, as described above, color filters 63 that absorb light of a predetermined wavelength separated into a plurality of structures 66A are arranged in the propagation direction of the light.

[0161] 11C , in the four unit pixels P arranged in 2 rows and 2 columns at the bottom left, a green filter 632 may be arranged in the unit pixel P having a plurality of structures 661, a red filter 634 may be arranged in the unit pixel P having a plurality of structures 662, a blue filter 631 may be arranged in the unit pixel P having a plurality of structures 623, and a green filter 633 may be arranged in the unit pixel P having a plurality of structures 664.

[0162] The multilayer wiring layer 70 is stacked on the second surface 51S2 side of the semiconductor substrate 51. The multilayer wiring layer 70 includes, for example, a conductor film and an insulating film, and has a plurality of wirings, vias, etc. The multilayer wiring layer 70 has a configuration in which a plurality of wirings are stacked with an insulating film interposed therebetween as an interlayer insulating film. The multilayer wiring layer 70 includes, for example, two or three or more layers of wirings.

[0163] The wiring of the multilayer wiring layer 70 is formed using a metal material such as aluminum (Al), copper (Cu), or tungsten (W). The wiring of the multilayer wiring layer 70 may be formed using polysilicon (Poly-Si) or other conductive materials. The interlayer insulating film may be formed using silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or the like.

[0164] The semiconductor substrate 51 and the multilayer wiring layer 70 are provided with the above-described readout circuit 31, for example, for each unit pixel P or for each plurality of unit pixels P. In addition to the above-described readout circuit 31, the multilayer wiring layer 70 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.

[0165] [Functions and Effects] In the photodetector 1 of this embodiment, a light guide section 66 in which a color filter 63 and a plurality of structural bodies 66A are arranged is provided in the OPB region 100b of the effective pixel region 100A and the peripheral pixel region 100B on the first surface 11S1 side, which is the light incident side S1 of the semiconductor substrate 11. In the OPB region 100b, the color filter 63 that absorbs light of a predetermined wavelength separated into the plurality of structural bodies 66A is arranged in the propagation direction of the light. This reduces the thickness of the color filter 63 arranged in the OPB region 100b. This is described below.

[0166] 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.

[0167] An optical black (OPB) region that determines a black reference signal is disposed outside the so-called active pixel region that outputs an image signal for generating an image. Reflected light propagating from the OPB region to the active pixel region is one of the factors that degrades the characteristics of the image sensor, and measures have been taken to address this. In a typical image sensor, a color filter, consisting of a stack of multiple filters that selectively transmit light of different wavelengths, is disposed in the OPB region to prevent the reflected light from the OPB region to the active pixel region. However, disposing a multilayer color filter in the OPB region creates a step between the active region and the OPB region, which can cause unevenness in the lens formation process or defocusing in the process of forming the nanopost structure described above.

[0168] In contrast, in the present embodiment, as described above, a light-guiding section 66 having a color filter 63 and a plurality of structures 66A arranged in the OPB region 100b of the effective pixel region 100A and the peripheral pixel region 100B is provided on the first surface 11S1 side, which is the light incident side S1 of the semiconductor substrate 11. In the OPB region 100b, a color filter 63 that absorbs light of a predetermined wavelength separated by the plurality of structures 66A is arranged in the propagation direction of the light. This makes it possible to suppress propagation of reflected light from the OPB region to the active pixel region without arranging a multi-layer color filter as described above in the OPB region 100b. In other words, compared to a typical image sensor, the thickness of the color filter 63 arranged in the OPB region 100b can be reduced, thereby eliminating the step between the effective pixel region 100A and the OPB region 100b.

[0169] As described above, in the photodetector 2 of this embodiment, the height of the unit pixels P can be made uniform between the effective pixel region 100A and the OPB region 100b, which reduces unevenness in the process of forming lenses and the occurrence of defocus in the process of forming the above-mentioned nanopost structures, etc., thereby making it possible to improve device characteristics.

[0170] 12 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 2A) according to Modification 3 of the present disclosure. The photodetector 2A 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 second embodiment.

[0171] In the above-described second embodiment, an example is shown in which a color filter 63 that absorbs light of a predetermined wavelength separated into a plurality of structures 66A is arranged in the OPB region 100b in the propagation direction of the light in order to suppress the propagation of reflected light from the OPB region to the active pixel region, but the present invention is not limited to this.

[0172] The photodetector 2A of this modified example is a photodetector that does not have a color filter 63 in the effective pixel region 100A. The photodetector 2A suppresses propagation of reflected light from the OPB region to the active pixel region by forming an uneven structure X that absorbs light of a predetermined wavelength on the surface of the light-shielding film 61 that extends into the OPB region 100b.

[0173] The concavo-convex structure X has a plurality of regions (for example, a first region 61A, a second region 61B, and a third region 61C) having concavo-convex shapes that absorb light of different wavelengths. The first region 61A corresponds to the blue filter 631 in the second embodiment, the second region 61B corresponds to the green filters 632 and 633 in the second embodiment, and the third region 61C corresponds to the red filter 634 in the second embodiment. In other words, in the OPB region 100b, as described above, any of the first region 61A, the second region 61B, and the third region 61C that absorbs light of a predetermined wavelength separated into the plurality of structures 66A is arranged in the propagation direction of the light.

[0174] In this way, in the photodetector 2A of this modification, the uneven structure X that absorbs light of a predetermined wavelength is formed on the surface of the light-shielding film 61 extending into the OPB region 100b. This makes it possible to suppress the propagation of reflected light from the OPB region to the active pixel region even in a photodetector that does not have a color filter 63 in the active pixel region 100A. Therefore, similar to the second embodiment, it is possible to improve the device characteristics.

[0175] 13 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector (photodetector 2B) according to a fourth modification of the present disclosure. The photodetector 2B 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 second embodiment.

[0176] In the second embodiment described above, an example was shown in which the surface of the light-shielding film 61 was processed to form the uneven structure X that absorbs light of a predetermined wavelength on the surface of the light-shielding film 61, but the present invention is not limited to this. In the photodetector 2B of this modification, an uneven structure is formed on the first surface 51S1 of the semiconductor substrate 51, and the uneven structure X is formed on the surface of the light-shielding film 61 by the uneven structure formed on the semiconductor substrate 51. Except for this point, the photodetector 2B has substantially the same configuration as the photodetector 2A of the third modification described above.

[0177] In this way, in the photodetector 2B of this modified example, a concave-convex structure is formed on the first surface 51S1 of the semiconductor substrate 51, and the concave-convex structure X is formed on the surface of the light-shielding film 61 based on the concave-convex structure formed on the semiconductor substrate 51. Even with this configuration, the photodetector 2B of this modified example can achieve the same effects as the photodetector 2A of the modified example 3 described above.

[0178] <5. Application Examples>

[0179] (Application Example 1) Furthermore, the above-described photodetector (for example, the photodetector 1) 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.

[0180] FIG. 14 is a block diagram showing an example of the configuration of electronic device 1000. As shown in FIG.

[0181] As shown in FIG. 14, the electronic device 1000 includes an optical system 1001, a photodetector 1, and a DSP (Digital Signal Processor) 1002, and is configured by connecting the DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 via a bus 1008, and is capable of capturing still images and moving images.

[0182] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from a subject and forms an image on the imaging surface of the photodetector 1 .

[0183] The photodetector 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal for each pixel, and supplies the signal to the DSP 1002 as a pixel signal.

[0184] The DSP 1002 performs various signal processing on the signal from the photodetector 1 to acquire an image, and temporarily stores the image data in the memory 1003. The image data stored in the memory 1003 is recorded in the recording device 1005 or supplied to the display device 1004 to display the image. In addition, the operation system 1006 accepts various operations by the user and supplies operation signals to each block of the electronic device 1000, and the power supply system 1007 supplies the power necessary to drive each block of the electronic device 1000.

[0185] 15A is a schematic diagram illustrating an example of the overall configuration of a light detection system 2000 including the light detection device 1. FIG. 15B 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 2002 may be, for example, the light detection device 1. 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.

[0186] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 15A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the object 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the object 2100 can be obtained from light L1, and distance information between the object 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be installed in, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 can be configured, for example, by a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can be, for example, an iTOF method, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100, for example, by using the time-of-flight (TOF) of light. The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can also be, for example, a structured light method or a stereo vision method. For example, in the structured light method, a predetermined pattern of light is projected onto the subject 2100, and the distance between the photodetector system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby measuring the distance between the photodetector system 2000 and the subject. The light emitting device 2001 and the light detecting device 2002 can be controlled synchronously by a system control unit 2003 .

[0187] 6. Application Example Application Example to an Endoscopic Surgery System The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0188] FIG. 16 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.

[0189] 16 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] FIG. 17 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.

[0210] 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 .

[0211] 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.

[0212] 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.

[0213] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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.

[0219] 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.

[0220] (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).

[0221] FIG. 18 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.

[0222] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 18, 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] 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. 18, 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.

[0232] FIG. 19 is a diagram showing an example of the installation position of the imaging unit 12031.

[0233] In FIG. 19, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0234] 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.

[0235] 19 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.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] The present disclosure has been described above by giving the first and second embodiments, variants 1 to 4, and application examples and applied examples. However, the present technology is not limited to the above-described embodiments, and various modifications are possible.

[0241] For example, in the above-described embodiments, an example is shown in which a single layer of light-guiding section 26 is provided, which has a plurality of structures 26A and medium 26B that is arranged around the plurality of structures 26A and has a refractive index different from that of the plurality of structures 26A. However, this is not limited to this, and a plurality of light-guiding sections may be stacked.

[0242] The photodetector of the present disclosure may be any device that receives incident light and converts the light into an electric charge. The output signal may be a signal of image information or a signal of ranging information. The photodetector may be applied to an image sensor, a ranging sensor, etc. Note that the present disclosure is not limited to back-illuminated image sensors, but may also be applied to front-illuminated image sensors.

[0243] Furthermore, the photodetector according to the present disclosure may also be applied as a distance measuring sensor capable of measuring distances using a time-of-flight (TOF) method. The light receiving element (photoelectric conversion unit) of each pixel may be an avalanche photodiode (APD). The light receiving element may be configured, for example, by a single-photon avalanche diode (SPAD). The photodetector may also be applied as a sensor capable of detecting events, for example, an event-driven sensor (also called an event vision sensor (EVS), event-driven sensor (EDS), dynamic vision sensor (DVS), etc.).

[0244] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0245] The present disclosure may also be configured as follows. According to the present technology configured as follows, a plurality of structures each having a size equal to or smaller than the wavelength of incident light that constitute a light guide section provided across the effective pixel region and the peripheral pixel region on the first surface side of the semiconductor substrate are arranged in the effective pixel region as well as in the peripheral pixel region around the effective pixel region. This makes it possible to prevent the shape of the plurality of structures arranged in the effective pixel region from being distorted. This makes it possible to improve device characteristics. (1) A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, the semiconductor substrate having an effective pixel region in which a plurality of pixels are arranged in an array, and a peripheral pixel region provided around the effective pixel region; a light guide portion provided on the first surface side of the semiconductor substrate across the effective pixel region and the peripheral pixel region, the light guide portion including a plurality of structures each having a size equal to or less than the wavelength of incident light and arranged in the effective pixel region and a medium having a refractive index different from that of the plurality of structures and provided so as to fill spaces between adjacent structures; and a photoelectric conversion portion embedded in the semiconductor substrate for each of the plurality of pixels, the photodetector comprising: a first surface of the semiconductor substrate and a second surface of the semiconductor substrate; (3) The photodetector according to (2), wherein the plurality of structures separate the incident light into light of a plurality of wavelengths, the color filter has a plurality of filters that selectively transmit light of different wavelengths, one filter that transmits light of a wavelength separated by the plurality of structures is arranged in the effective pixel region in a propagation direction of the light of the wavelength separated by the plurality of structures, and another filter that absorbs light of the wavelength in a propagation direction of the light of the wavelength separated by the plurality of structures is arranged in the peripheral pixel region. (4) The photodetector according to any one of (1) to (3), further comprising a light absorption layer provided on the first surface of the semiconductor substrate in the peripheral pixel region, the light absorption layer having an uneven surface.(5) The photodetector according to (4), wherein the plurality of structures separate the incident light into light of a plurality of wavelengths, the light absorption layer has a plurality of concavo-convex structures as the concavo-convex structures that absorb light of different wavelengths, and in the peripheral pixel region, a single concavo-convex structure that absorbs light of a wavelength separated by the plurality of structures is arranged in the propagation direction of the light of the wavelength separated by the plurality of structures. (6) The photodetector according to (4) or (5), wherein the semiconductor substrate has a concavo-convex structure on the first surface of the peripheral pixel region, and the concavo-convex structure of the light absorption layer is formed by the concavo-convex structure provided on the first surface of the semiconductor substrate. (7) The photodetector according to any one of (1) to (6), wherein the peripheral pixel region includes an optical black region around the effective pixel region, and the plurality of structures are arranged in the effective pixel region and the optical black region. (8) The photodetector according to (7), wherein the plurality of structures have different layouts in the effective pixel region and the optical black region. (9) The photodetector according to (7) or (8), wherein the plurality of structures arranged in the effective pixel region have freeform columnar shapes, and the plurality of structures arranged in the optical black region have circular columnar shapes. (10) The photodetector according to any one of (1) to (9), wherein, of the plurality of structures provided in the peripheral pixel region, the plurality of structures arranged in the vicinity of the effective pixel region guide the incident light to the effective pixel region. (11) The photodetector according to any one of (7) to (10), wherein the plurality of structures are arranged to the outside of the optical black region. (12) The photodetector according to (11), wherein, of the plurality of structures provided in the peripheral pixel region, the plurality of structures arranged outside the optical black region guide the incident light to the optical black region. (13) The photodetector according to any one of (7) to (12), further comprising a spacer layer between the first surface of the semiconductor substrate and the light-guiding section, wherein the plurality of structures arranged in the optical black region extend into the spacer layer.(14) The photodetector according to any one of (7) to (13), further comprising a color filter between the first surface of the semiconductor substrate and the light guiding unit, the color filter being provided in the effective pixel region and the optical black region. (15) The photodetector according to (14), wherein the color filter includes a first filter that transmits light of a first wavelength, a second filter that transmits light of a second wavelength, and a third filter that transmits light of a third wavelength, the first filter and the second filter being arranged in parallel in the optical black region, and the third filter being stacked on the first filter and the second filter. (16) The photodetector according to (15), wherein the plurality of structures arranged in the optical black region separate the incident light into light of the first wavelength, light of the second wavelength, and light of the third wavelength, and in the optical black region, the light of the second wavelength and the light of the third wavelength separated by the plurality of structures are guided to the first filter, and the light of the first wavelength separated by the plurality of structures is guided to the second filter. (17) The photodetector according to (15) or (16), wherein the plurality of pixels include a first pixel, a second pixel, and a third pixel, and the first pixel has the first filter and a first photoelectric conversion unit that photoelectrically converts the light of the first wavelength that has passed through the first filter, the second pixel has the second filter and a second photoelectric conversion unit that photoelectrically converts the light of the second wavelength that has passed through the second filter, and the third pixel has the third filter and a third photoelectric conversion unit that photoelectrically converts the light of the third wavelength that has passed through the third filter. (18) The photodetector according to any one of (15) to (17), wherein the light of the first wavelength is light in a red wavelength region, the light of the second wavelength is light in a green wavelength region, and the light of the third wavelength is light in a blue wavelength region.

[0246] This application claims priority based on Japanese Patent Application No. 2024-099614, filed on June 20, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0247] 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 opposing first and second surfaces, and having an effective pixel area in which a plurality of pixels are arranged in an array, and a peripheral pixel area provided around the effective pixel area; a light guide section provided on the first surface side of the semiconductor substrate across the effective pixel area and the peripheral pixel area, each of which has a size equal to or less than the wavelength of incident light, and which includes a plurality of structures arranged in the effective pixel area and the peripheral pixel area, and a medium provided so as to fill the spaces between adjacent structures and having a refractive index different from that of the plurality of structures; and a photoelectric conversion section embedded in the semiconductor substrate for each of the plurality of pixels, which performs photoelectric conversion on light incident via the light guide section.

2. The photodetector according to claim 1, further comprising a color filter between the first surface of the semiconductor substrate and the light guide section, the color filter being provided across the effective pixel region and the peripheral pixel region.

3. The photodetector according to claim 2, wherein the plurality of structures separate the incident light into light of a plurality of wavelengths, the color filter has a plurality of filters that selectively transmit light of different wavelengths, the effective pixel region has one filter that transmits light of the one wavelength separated by the plurality of structures in the propagation direction of the light of the one wavelength, and the peripheral pixel region has another filter that absorbs light of the one wavelength in the propagation direction of the light of the one wavelength separated by the plurality of structures.

4. The photodetector according to claim 1, further comprising a light absorbing layer provided on the first surface of the semiconductor substrate in the peripheral pixel region, the light absorbing layer having an uneven surface.

5. The photodetector according to claim 4, wherein the plurality of structures separate the incident light into light of a plurality of wavelengths, the light absorption layer has a plurality of uneven structures as the uneven structure that absorb light of different wavelengths, and in the peripheral pixel region, one uneven structure that absorbs light of a wavelength separated by the plurality of structures is arranged in the propagation direction of the light of the wavelength.

6. The photodetector according to claim 4, wherein the semiconductor substrate has a concave-convex structure on the first surface of the peripheral pixel region, and the concave-convex structure of the light absorption layer is formed by the concave-convex structure provided on the first surface of the semiconductor substrate.

7. The photodetector device according to claim 1, wherein the peripheral pixel region includes an optical black region around the effective pixel region, and the plurality of structures are arranged in the effective pixel region and the optical black region.

8. The photodetector device according to claim 7, wherein the plurality of structures have different layouts in the effective pixel area and the optical black area.

9. The photodetector device according to claim 7, wherein the plurality of structures arranged in the effective pixel region have a freeform columnar shape, and the plurality of structures arranged in the optical black region have a circular columnar shape.

10. The photodetector device according to claim 1, wherein, of the plurality of structures provided in the peripheral pixel region, the plurality of structures arranged in the vicinity of the effective pixel region guide the incident light to the effective pixel region.

11. The photodetector device according to claim 7, wherein the plurality of structures are arranged to the outside of the optical black area.

12. The photodetector device of claim 11, wherein, of the plurality of structures provided in the peripheral pixel region, the plurality of structures arranged outside the optical black region guide the incident light to the optical black region.

13. The photodetector device according to claim 7, further comprising a spacer layer between the first surface of the semiconductor substrate and the light guide portion, and the plurality of structures arranged in the optical black region extend into the spacer layer.

14. The photodetector according to claim 7, further comprising a color filter between the first surface of the semiconductor substrate and the light guide section, the color filter being provided in the effective pixel area and the optical black area.

15. The photodetector device of claim 14, wherein the color filters include a first filter that transmits light of a first wavelength, a second filter that transmits light of a second wavelength, and a third filter that transmits light of a third wavelength, and in the optical black region, the first filter and the second filter are arranged in parallel, and the third filter is stacked on the first filter and the second filter.

16. The photodetector device of claim 15, wherein the plurality of structures arranged in the optical black region separate the incident light into light of the first wavelength, light of the second wavelength, and light of the third wavelength, and in the optical black region, the light of the second wavelength and the light of the third wavelength separated by the plurality of structures are guided to the first filter, and the light of the first wavelength separated by the plurality of structures is guided to the second filter.

17. The photodetector according to claim 15, wherein the plurality of pixels include a first pixel, a second pixel, and a third pixel, the first pixel having the first filter and a first photoelectric conversion unit that photoelectrically converts light of the first wavelength that has passed through the first filter, the second pixel having the second filter and a second photoelectric conversion unit that photoelectrically converts light of the second wavelength that has passed through the second filter, and the third pixel having the third filter and a third photoelectric conversion unit that photoelectrically converts light of the third wavelength that has passed through the third filter.

18. The photodetector according to claim 15, wherein the light of the first wavelength is light in the red wavelength region, the light of the second wavelength is light in the green wavelength region, and the light of the third wavelength is light in the blue wavelength region.

Images