Photodetector

Abstract

A photodetector includes a first base body including a first semiconductor substrate on which a first photoelectric conversion element is arranged, a second base body, and a light shielding body. The first photoelectric conversion element converts incident light into an electric charge. The second substrate is disposed on a side opposite to the light incident side of the first substrate, and includes a second semiconductor substrate on which a second photoelectric conversion element is disposed. The second photoelectric conversion element converts incident light into an electric charge. The light shielding body is disposed along a side surface periphery of the second photoelectric conversion element when viewed from the light incident side. The light shielding body extends at least through the second semiconductor substrate in the thickness direction from the light incident side surface of the second base. The light shielding body blocks light from the second photoelectric conversion element.

Description

Technical Field

[0001] This invention relates to a photodetector. Background Technology

[0002] Patent Document 1 discloses a solid-state imaging device. This solid-state imaging device includes a structure comprising a first photoelectric conversion layer, a second photoelectric conversion layer, and a third photoelectric conversion layer stacked sequentially from the light incident side. A first isolator is disposed around the first photoelectric conversion layer. Similarly, a second isolator is disposed around the second photoelectric conversion layer, and a third isolator is disposed around the second photoelectric conversion layer. Solid-state imaging devices with this structure can perform color separation of light for each stacked photoelectric conversion layer. Citation List Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-232761 Summary of the Invention

[0004] In the aforementioned solid-state imaging device, the isolator is disposed in the region corresponding to the side of the photoelectric conversion layer. However, light leakage paths exist between the stacked interfaces of the photoelectric conversion layer and the isolator, where photoelectric conversion layers arranged adjacent to each other in the planar direction. For example, a second isolator is disposed between second photoelectric conversion layers arranged adjacent to each other in the planar direction. Light leakage paths exist between the stacked interfaces of the layer where the first photoelectric conversion layer is disposed and the second isolator. Therefore, it is desirable to develop a photodetector that can effectively suppress or prevent color mixing between photoelectric conversion layers arranged adjacent to each other.

[0005] A photodetector according to a first embodiment of the present invention includes a first substrate, a second substrate, and a light-shielding body. The first substrate includes a first semiconductor substrate in which a first photoelectric conversion element is disposed. The first photoelectric conversion element converts incident light into electrical charge. The second substrate is disposed on the side of the first substrate opposite to the light-incident side and includes a second semiconductor substrate in which a second photoelectric conversion element is disposed. The second photoelectric conversion element converts incident light into electrical charge. Viewed from the light-incident side, the light-shielding body is disposed around the side of the second photoelectric conversion element. The light-shielding body extends at least through the second semiconductor substrate in the thickness direction from the surface of the second substrate located on the light-incident side. The light-shielding body blocks light from the second photoelectric conversion element.

[0006] In the photodetector according to the second embodiment of the present invention, the first photoelectric conversion element in the photodetector according to the first embodiment includes a photodiode. Additionally, the second photoelectric conversion element includes an avalanche diode, which multiplies the carriers generated by photons of incident light.

[0007] The photodetector of the third embodiment of this disclosure further includes a third substrate in the photodetector according to the first or second embodiment. The third substrate is disposed on the side of the second substrate opposite to the first substrate and includes a third semiconductor substrate on which circuitry is mounted. The circuitry is electrically connected to at least one of the first and second photoelectric conversion elements. Attached Figure Description

[0008] Figure 1 This is a vertical cross-sectional view of the main part of the photodetector according to the first embodiment of the present invention. Figure 2 yes Figure 1 Plan view of the main part of the photodetector (along...) Figure 1 (The planar construction diagram obtained from the section line AA shown). Figure 3 yes Figure 1 Plan view of the main part of the photodetector (along...) Figure 1 (The planar construction diagram obtained from the section line BB shown). Figure 4 It is shown Figure 1 The circuit diagram of the first photoelectric conversion element and its readout circuit in the photodetector is shown. Figure 5 It is shown Figure 1 The circuit diagram shown is of the second photoelectric conversion element and its readout circuit in the photodetector. Figure 6 Is with Figure 1 A first process cross-sectional view is provided to illustrate the manufacturing method of the photodetector according to the first embodiment, step by step. Figure 7 This is a cross-sectional view of the second process. Figure 8 This is a cross-sectional view of the third process. Figure 9 This is a cross-sectional view of the fourth process. Figure 10 This is a cross-sectional view of the fifth process. Figure 11 This is a cross-sectional view of the sixth process. Figure 12 This is a vertical cross-sectional view of the main part of the photodetector according to the second embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 13 This is a vertical cross-sectional view of the main part of the photodetector according to the third embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 14 yes Figure 13 Plan view of the main part of the photodetector (along...) Figure 13 The cross-sectional line CC shown is obtained from the planar structural diagram, and is consistent with... Figure 3 Correspondingly. Figure 15 This is a planar structural diagram of the main part of the photodetector according to a modified example of the third embodiment, and is consistent with... Figure 14 Correspondingly. Figure 16 This is a vertical cross-sectional view of the main part of the photodetector according to the fourth embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 17 This is a vertical cross-sectional view of the main part of the photodetector according to the fifth embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 18 This is a vertical cross-sectional view of the main part of the photodetector according to the sixth embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 19 This is a vertical cross-sectional view of the main part of the photodetector according to the seventh embodiment of the present invention, and is consistent with... Figure 1 Correspondingly. Figure 20 This is a block diagram illustrating a schematic example of the construction of a vehicle control system. Figure 21 This diagram illustrates an example of the installation location of the vehicle exterior information detection unit and the imaging unit. Detailed Implementation

[0009] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the description will proceed in the following order. 1. First Embodiment The first embodiment is a first example of applying this technology to a photodetector. In the first embodiment, the pixel structure, circuit structure, and manufacturing method of the photodetector will be described. In particular, in the first embodiment, the structure of the photoelectric conversion element, the structure of the light-shielding body, and the manufacturing method thereof will be described. 2. Second Embodiment The second embodiment is a second example of changing the structure of the light-shielding body in the solid-state imaging device according to the first embodiment. 3. Third Embodiment The third embodiment is a third example of changing the structure of the light-shielding body in the solid-state imaging device according to the second embodiment. 4. Fourth Embodiment The fourth embodiment is a fourth example of changing the connection structure of the light-shielding body in the solid-state imaging apparatus according to the third embodiment. 5. Fifth Embodiment The fifth embodiment is a fifth example of changing the structure of the light-shielding body in the solid-state imaging apparatus according to the fourth embodiment. 6. Sixth Embodiment The sixth embodiment is a sixth example of changing the structure of the light-shielding body in the solid-state imaging apparatus according to the first embodiment. 7. Seventh Embodiment The seventh embodiment is a seventh example of changing the structure of the light-shielding body in the solid-state imaging apparatus according to the first embodiment. 8. Application examples on mobile devices This application example illustrates how this technology can be applied to a vehicle control system, which is an example of a mobile body control system. 9. Other embodiments <1. First Embodiment>

[0010] Reference Figures 1 to 11 The photodetector 1 according to the first embodiment of this disclosure is described. Here, in the accompanying drawings, for convenience, the arrow X indicates a planar direction of the photodetector 1 placed on the plane. The arrow Y indicates another planar direction orthogonal to the arrow X. Additionally, the arrow Z indicates an upward direction orthogonal to both the arrow X and arrow Y. That is, the arrow X, arrow Y, and arrow Z coincide exactly with the X-axis, Y-axis, and Z-axis of the three-dimensional coordinate system, respectively. Furthermore, the opposite direction of the arrow Z is the incident direction of the incident light L. It should be noted that each of these directions is indicated for the purpose of making the specification easier to understand and does not limit the directions in this technology. [Construction of Photodetector 1] (1) Circuit structure of photodetector 1

[0011] Figure 4 An example of the circuit construction of the first photoelectric conversion element 11 and its first readout circuit RE1 in the photodetector 1 according to the first embodiment is shown. Figure 5 An example of the circuit construction of the second photoelectric conversion element 21 and its second readout circuit RE2 in the photodetector 1 is shown.

[0012] like Figure 4 and Figure 5 As shown, the photodetector 1 according to the first embodiment includes two types of photoelectric conversion elements, namely a first photoelectric conversion element 11 and a second photoelectric conversion element 21. These two photoelectric conversion elements (i.e., the first photoelectric conversion element 11 and the second photoelectric conversion element 21) form a pixel 2 (see...). Figure 1 ). like Figure 4As shown, the first photoelectric conversion element 11 is electrically connected to the first readout circuit RE1. Meanwhile, as... Figure 5 As shown, the second photoelectric conversion element 21 is electrically connected to the second readout circuit RE2. This will be explained in detail below. (1-1) Circuit structure of photoelectric conversion element 11 and first readout circuit RE1

[0013] like Figure 4 As shown, the first photoelectric conversion element 11 includes a photodiode. The photodiode is formed at the pn junction portion between the anode region and the cathode region. The first photoelectric conversion element 11 converts incident light L (see...) Figure 1 The visible light is converted into electrical charge (electrical signal). Here, the first photoelectric conversion element 11 converts visible light into electrical charge. Visible light includes the red, green, and blue light bands. The anode region of the first photoelectric conversion element 11 is electrically connected to a fixed power supply. Here, the anode region is connected, for example, to a grounded power supply VSS. The cathode region is electrically connected to the floating diffuser FD via the transfer transistor TG. The floating diffuser FD is electrically connected to the first readout circuit RE1.

[0014] One of the two main electrodes of the transmission transistor TG is electrically connected to the first photoelectric conversion element 11. The other main electrode is electrically connected to the floating diffuser FD. The gate electrode receives the transmission signal.

[0015] In the first embodiment, a first readout circuit RE1 is provided for the four first photoelectric conversion elements 11 and the four transmission transistors TG, serving as a pixel circuit. The first readout circuit RE1 is configured to read out the charge converted from light at the first photoelectric conversion elements 11. The first readout circuit RE1 includes at least a reset transistor RST, an amplification transistor AMD, and a selection transistor SEL. Additionally, the first readout circuit RE1 may also include a floating diffuser gain switching transistor (not shown).

[0016] In the reset transistor RST, one of its two main electrodes is electrically connected to the floating diffuser FD. The other main electrode is electrically connected to the power supply voltage VDD. The gate electrode receives the reset signal. One of the two main electrodes of the amplifying transistor AMP is electrically connected to the power supply voltage VDD. The other main electrode is electrically connected to one of the two main electrodes of the select transistor SEL. The floating diffuser FD is electrically connected to the gate electrode. The other main electrode of the select transistor SEL is electrically connected to the output signal line (vertical signal line) VSL. The gate electrode receives the select signal.

[0017] Here, including but not limited to the aforementioned transmission transistor TG and the reset transistor RST of the first readout circuit RE1, all transistors use insulated gate field-effect transistors (IGFETs). The term "IGFET" as used herein includes MOSFETs (metal-oxide-semiconductor field-effect transistors) and MISFETs (metal-insulator-semiconductor field-effect transistors).

[0018] In the photodetector 1, the first readout circuit RE1 is also connected to an image processing circuit (not shown). This image processing circuit includes, for example, an analog-to-digital converter (ADC) and a digital signal processor (DSP). The first photoelectric conversion element 11 converts light into electrical charge, which is an analog signal. This analog signal is amplified in the first readout circuit RE1. The ADC converts the analog signal output from the first readout circuit RE1 into a digital signal. The DSP performs functional processing on the digital signal. That is, the image processing circuit performs signal processing for generating an image.

[0019] It should be noted that a first readout circuit RE1 can be configured for one, two, or eight first photoelectric conversion elements 11 and one, two, or eight transmission transistors TG. Here, "first readout circuit RE1" or "image processing circuit" (not shown) corresponds to the "circuit" electrically connected to the first photoelectric conversion element 11 according to the present technology. (1-2) Circuit construction of the second photoelectric conversion element 21 and the second readout circuit RE2

[0020] like Figure 5 As shown, the second photoelectric conversion element 21 includes a single-photon avalanche diode (hereinafter referred to as "SPAD"). The SPAD includes a multiplication region in which carriers generated by photons of incident light L are multiplied. In the first embodiment, the second photoelectric conversion element 21 uses photons of infrared light to generate carriers. Furthermore, the SPAD is formed at the pn junction portion between the anode region and the cathode region. It should be noted that the second photoelectric conversion element 21 is not limited to infrared light, but can also generate charge carriers using photons from visible light. These charge carriers can be used for imaging. The anode region of the SPAD receives the anode voltage VA. The anode voltage VA is a large negative voltage that allows for avalanche multiplication. In other words, the anode voltage VA is a voltage higher than or equal to the breakdown voltage. The anode voltage VA is, for example, -20V.

[0021] As an alternative to a SPAD, the second photoelectric conversion element 21 can be configured to include an avalanche photodiode (APD) or a silicon photomultiplier (SiPM) operating in the nonlinear region. Alternatively, the second photoelectric conversion element 21 may also include a photodiode, similar to the first photoelectric conversion element 11.

[0022] The second photoelectric conversion element 21 is electrically connected to the second readout circuit RE2. That is, the cathode region of the SPAD is connected to the second readout circuit RE2. For example, a 1V voltage to be clamped on the side of the second readout circuit RE2 is applied to the cathode region of the second photoelectric conversion element 21. Here, the second readout circuit RE2 includes a quench element Qe, an inverter INV, a counter COU, a phase-locked loop (PLL), and an interface circuit IF. The quench element Qe draws the avalanche current and resets the second readout circuit RE2. It should be noted that the second photoelectric conversion element 21 can be connected to the second readout circuit RE2 via a protection circuit (not shown).

[0023] Furthermore, the interface circuit IF is configured to be electrically connected to, for example, a time measurement circuit (not shown). The photodetector 1 can form a ranging system including this time measurement circuit.

[0024] Here, "second readout circuit RE2" or "time measurement circuit" (not shown) corresponds to the "circuit" electrically connected to the second photoelectric conversion element 21 according to the present technology. (2) Overall structure of photodetector 1

[0025] Next, the specific device structure of the photodetector 1 will be described. Figure 1 An example of a vertical cross-sectional structure corresponding to multiple pixels 2 of the photodetector 1 is shown. Figure 2 An example of a planar structure of a plurality of pixels 2 of a photodetector 1 and an optical filter 4 arranged in the pixels 2 is shown. Figure 3 An example of a planar structure of the second photoelectric conversion element 21 and the light shield 6 of the photodetector 1 is shown.

[0026] like Figure 1As shown, the photodetector 1 according to the first embodiment includes a first substrate 10, a second substrate 20, and a third substrate 30, and is configured to have a three-layer substrate structure. The first substrate 10, the second substrate 20, and the third substrate 30 are stacked sequentially in a direction opposite to the direction of arrow Z. Here, the direction opposite to the direction of arrow Z coincides with the light incident direction L; therefore, in other words, the first substrate 10, the second substrate 20, and the third substrate 30 are arranged sequentially along the incident direction of the incident light L.

[0027] The first substrate 10 includes a first semiconductor substrate 12 on which a first photoelectric conversion element 11 is disposed. The second substrate 20 includes a second semiconductor substrate 22 on which a second photoelectric conversion element 21 is disposed. Furthermore, the third substrate 30 includes a third semiconductor substrate 32 on which a circuit 31 is disposed. The circuit 31 includes one or more of a first readout circuit RE1, an image processing circuit, a second readout circuit RE2, and a time measurement circuit.

[0028] It should be noted that in this technology, the photodetector 1 can be configured to have a double-layer substrate structure including a first substrate 10 and a second substrate 20. Alternatively, the photodetector 1 can include a fourth substrate or more substrates and can be configured to have a substrate structure including four or more layers. (3) Construction of the first substrate 10 and the first photoelectric conversion element 11

[0029] The first substrate 10 includes a first semiconductor substrate 12 and a first wiring layer 13 disposed on a surface 12B of the first semiconductor substrate 12 located on the opposite side of the direction of arrow Z. In the first embodiment, the first semiconductor substrate 12 is a single-crystal silicon (Si) substrate. More specifically, the single-crystal Si substrate includes an n-type semiconductor region as a first conductivity type and a p-type semiconductor region as a second conductivity type in a predetermined region. Here, the predetermined region is, for example, the region where the first photoelectric conversion element 11 is disposed. That is, although the detailed structure is not shown and described, the first photoelectric conversion element 11 is configured as a photodiode including a p-type semiconductor region as an anode region and an n-type semiconductor region as a cathode region in the first semiconductor substrate 12.

[0030] Furthermore, the first semiconductor substrate 12 can be one or more substrates selected from crystalline Si, amorphous Si, microcrystalline Si, crystalline selenium, amorphous selenium, and chalcopyrite compounds. Chalcopyrite compounds include CIGS (CuInGaSe), CIS (CuInSe2), CuInS2, CuAlS2, CuAlSe2, CuGaS2, CuGaSe2, AgAlS2, AgAlSe2, AgInS2, and AgInSe2. Alternatively, the first semiconductor substrate 12 may be one or more compound semiconductor substrates selected from GaAs, InP, AlGaAs, InGaP, AlGaInP, InGaAsP, CdSe, CdS, In2Se3, In2S3, Bi2Se3, Bi2S3, ZnSe, ZnS, PbSe, and PbS, which are III-V compound semiconductors.

[0031] Multilayer wiring 131 and plug wiring 132 that electrically connect components to wiring 131 are arranged in the first wiring layer 13. Here, the transmission transistor TG is shown as a component in a simplified manner. Wiring 131 uses wiring materials such as Cu or transparent electrode materials such as IZO (indium zinc oxide) or ITO (indium tin oxide). For example, plug wiring 132 uses wiring materials such as W. Each of the wiring 131 and the plug wiring 132 is embedded in the insulating layer 135. In fact, the insulating layer 135 is formed by stacking multiple layers of insulating film. The insulating film may be, for example, SiO2. (4) Construction of pixel 2

[0032] Here, when viewed from the incident direction of the incident light L (hereinafter referred to as "in the planar view"), the planar shape of pixel 2 is formed as a rectangle. Here, the planar shape of pixel 2 is formed as a square. Although not shown in detail, the planar shape of the first photoelectric conversion element 11 is formed as a rectangle, just like the planar shape of pixel 2, and is formed as a similar shape that is smaller than the planar shape of pixel 2.

[0033] A plurality of first photoelectric conversion elements 11 are arranged in a pixel 2. More specifically, in the first embodiment, a total of twelve first photoelectric conversion elements 11 are regularly arranged in the peripheral portion along each side of a pixel 2. That is, four first photoelectric conversion elements 11 are arranged in a row along the Y direction on each of the two sides of the pixel 2 that face each other along the X direction. At the same time, two first photoelectric conversion elements 11 are arranged in a row along the X direction on each of the two sides of the pixel 2 that face each other along the Y direction. The first photoelectric conversion element 11 is not located in the middle portion of pixel 2. This area forms the incident path for incident light L incident on the second photoelectric conversion element 21.

[0034] Pixel isolators 121 are arranged between first photoelectric conversion elements 11 that are adjacent to each other along the X and Y directions. Although their detailed structure and description are omitted, for example, pixel isolators 121 have trenches and include embedded members. For example, the trenches are formed from a surface 12A of the first semiconductor substrate 12 in the Z direction along the thickness direction of the first semiconductor substrate 12. The embedded members are embedded in the trenches. The trenches of the pixel isolator 121 only need to electrically and optically isolate adjacent first photoelectric conversion elements 11 from each other, regardless of whether the trenches extend through the first semiconductor substrate 12. Furthermore, similar to the trenches, the embedded element only needs to be able to electrically and optically isolate adjacent first photoelectric conversion elements 11 from each other. For example, SiO2 can be practically used as the insulating material for the embedded element.

[0035] It should be noted that the arrangement pattern of the first photoelectric conversion element 11 described in the first embodiment is merely an example. For example, in this technology, in a pixel 2, three photoelectric conversion elements 11 can be arranged along the X-direction and three photoelectric conversion elements 11 can be arranged along the Y-direction, corresponding to the red wavelength range, green wavelength range, and blue wavelength range (hereinafter referred to as "RGB"). Alternatively, in a pixel 2, similarly, one photoelectric conversion element 11 can be arranged along the X-direction and one photoelectric conversion element 11 can be arranged along the Y-direction. Alternatively, in a pixel 2, similarly, two photoelectric conversion elements 11 can be arranged along the X-direction and two photoelectric conversion elements 11 can be arranged along the Y-direction. In addition, in this technology, the second photoelectric conversion element 21 may not be arranged in the middle part of the pixel 2, but in the peripheral part of the pixel 2. (5) Construction of optical filter 4

[0036] like Figure 1 and Figure 2 As shown, the optical filter 4 is arranged in the direction of arrow Z of the first photoelectric conversion element 11, separated by a protective film (not indicated by reference numerals). In other words, the optical filter 4 is arranged on the surface 12A of the first semiconductor substrate 12, separated by a protective film. The optical filter 4 is arranged for each of the first photoelectric conversion elements 11.

[0037] Similar to the planar shape of the first photoelectric conversion element 11, the planar shape of the optical filter 4 is rectangular. Furthermore, the planar dimensions of the optical filter 4 are substantially the same as those of the first photoelectric conversion element 11. In the first embodiment, the first photoelectric conversion element 11 is configured to perform photoelectric conversion on light in the visible light band. Therefore, three types of optical filters 4 are arranged in one pixel 2. These three types of optical filters 4 are optical filters 4 that transmit light in the red wavelength range, optical filters 4 that transmit light in the blue wavelength range, and optical filters 4 that transmit light in the green wavelength range. In the figure, the optical filter 4 that transmits light in the red wavelength range is indicated by the reference numeral "R". Similarly, the optical filter 4 that transmits light in the blue wavelength range is indicated by the reference numeral "B", and the optical filter 4 that transmits light in the green wavelength range is indicated by the reference numeral "G". In a pixel 2, four optical filters 4 indicated by reference numeral R, four optical filters 4 indicated by reference numeral B, and four optical filters 4 indicated by reference numeral G are arranged alternately in an appropriate manner. Here, four first photoelectric conversion elements 11, each with four corresponding filters 4 indicated by the same reference numerals, are connected to a readout circuit RE1 (see Figure 1). Figure 4 ).

[0038] Optical filter 4 includes, for example, a pigment onto a resin material to apply color. More specifically, the resin can be, for example, an organic resin material such as a phthalocyanine derivative. (6) Construction of optical lens 5

[0039] like Figure 1 As shown, the optical lens 5 is arranged on the side of the optical filter 4 opposite to the first photoelectric conversion element 11. Although not shown, the optical lens 5 is formed in a circular shape for each first photoelectric conversion element 11 in the plan view. In addition, when viewed from the direction of arrow Y (hereinafter referred to as "in the side view"), the optical lens 5 is bent toward the incident side of the incident light L and is formed in a curved shape for focusing the incident light L. In other words, the optical lens 5 is a so-called on-chip lens and is integrally formed above the plurality of first photoelectric conversion elements 11. The optical lens 5 includes, for example, a transparent resin material. (7) Construction of the second substrate 20 and the second photoelectric conversion element 21

[0040] like Figure 1 As shown, the second substrate 20 includes a second semiconductor substrate 22, a second wiring layer 23, and an insulator 24. The second wiring layer 23 is disposed on the surface 22B of the second semiconductor substrate 22 in the direction opposite to arrow Z. The insulator 24 is disposed on the surface 22A of the second semiconductor substrate 22 in the direction of arrow Z. The first substrate 10 is stacked on the surface 22A of the second semiconductor substrate 22, with the insulator 24 in between.

[0041] In the first embodiment, the second semiconductor substrate 22 uses a material similar to that of the first semiconductor substrate 12. That is, the second semiconductor substrate 22 is a single-crystal Si substrate.

[0042] like Figure 1 and Figure 3 As shown, within the region of pixel 2, the second photoelectric conversion element 21 overlaps with the first photoelectric conversion element 11, and the second photoelectric conversion element 21 is arranged in the second semiconductor substrate 22 of the second substrate 20. That is, the first photoelectric conversion element 11 and the second photoelectric conversion element 21 are stacked sequentially along the incident direction of the incident light L. In other words, the first photoelectric conversion element 11 and the second photoelectric conversion element 21 are stacked perpendicularly along the direction of arrow Z.

[0043] Although detailed structures and descriptions are omitted, in the first embodiment, the second photoelectric conversion element 21 includes a SPAD. That is, the second photoelectric conversion element 21 includes: an anode region comprising a p-type semiconductor region in the second semiconductor substrate 22; and a cathode region comprising an n-type semiconductor region in the second semiconductor substrate 22.

[0044] A second photoelectric conversion element 21 is arranged for each pixel 2. For example... Figure 3 As shown, the second photoelectric conversion element 21 is arranged in the middle part of pixel 2. In the planar view, the planar shape of the second photoelectric conversion element 21 is formed as a rectangle similar to the planar shape of pixel 2. Furthermore, the light-shielding body 6 is arranged around the side of the second photoelectric conversion element 21. The light-shielding body 6 is arranged to overlap with the positions corresponding to the spaces between pixels 2 in the planar view. The planar shape of the light-shielding body 6 is formed as a grid shape. The light-shielding body 6 electrically and optically isolates the second photoelectric conversion elements 21 that are adjacent to each other in each of the X and Y directions from each other. The structure of the light-shielding body 6 will be explained later.

[0045] The second wiring layer 23 includes a multilayer wiring 231 and a plug wiring 232 that electrically connects the component to the wiring 231. Here, the component is the second photoelectric conversion element 21. Wiring 231 uses wiring materials such as Cu, for example. Plug wiring 232 uses wiring materials such as W, for example. Each of wiring 231 and plug wiring 232 is embedded in insulating layer 235. In fact, insulating layer 235 is formed by stacking multiple layers of insulating film. The insulating film may be, for example, SiO2.

[0046] The insulator 24 serves as a protective layer for bonding the second semiconductor substrate 22 of the second substrate 20 to the first wiring layer 13 of the first substrate 10. For example, the insulator 24 is made of SiO2. (8) Structure of light-shielding body 6

[0047] like Figure 1 and Figure 3 As shown, when viewed from the incident side of the incident light L (in the plan view), the light-shielding body 6 is arranged around the side of the second photoelectric conversion element 21. In addition, the light-shielding body 6 is configured to extend at least through the second semiconductor substrate 22 in the thickness direction from the surface of the second substrate 20 located on the incident side of the incident light L.

[0048] More specifically, in the first embodiment, the second substrate 20 includes an insulator 24 on the surface 22A of the second semiconductor substrate 22 located on the side of the first substrate 10. A light-shielding body 6 extends from the surface 24A of the insulator 24 located on the side of the first substrate 10 through the second semiconductor substrate 22. That is, the position of the end face 6A of the light-shielding body 6 in the direction of arrow Z coincides with the position of the surface 24A of the insulator 24. Furthermore, the second substrate 20 includes a second wiring layer 23 on the surface 22B of the second semiconductor substrate 22 located on the side of the third substrate 30. A light-shielding body 6 is arranged to extend to and reach the wiring 231 of the second wiring layer 23. That is, the position of the end face 6B of the light-shielding body 6 opposite to the direction of arrow Z coincides with the position of the surface of the wiring 231 in the direction of arrow Z. In other words, the end face 6B of the light-shielding body 6 is in contact with the wiring 231.

[0049] The light-shielding body 6 has a groove 61 and includes an embedded member 62. The embedded member 62 is embedded in the groove 61 and has light-shielding properties.

[0050] The trench 61 is formed to extend from the surface 24A of the insulator 24 of the second substrate 20 through the insulator 24 and the second semiconductor substrate 22, and to a depth reaching the wiring 231 of the second wiring layer 23.

[0051] In the first embodiment, the embedded part 62 includes a first embedded part 621 and a second embedded part 622. The first embedded part 621 is arranged along the inner wall of the trench 61. The first embedded part 621 is, for example, an embedding blocking metal. The embedding blocking metal is, for example, a metal material such as W or TiW. In addition, the first embedded part 621 uses an insulating material such as SiO2 as an embedding insulator. The second embedded part 622 is embedded through the first embedded part 621, which is located between the inner wall of the trench 61 and the second embedded part 622. The second embedded part 622 is made of a material with light-shielding properties or a material with excellent light-reflecting properties. Specifically, the second embedded part 622 includes one or more metallic materials selected from Cu, W, Al, Ag, Ta and Co, or an alloy material formed by combining two or more of these materials. (9) Construction of the third substrate 30 and circuit 31

[0052] like Figure 1 As shown, the third substrate 30 includes a third semiconductor substrate 32 and a third wiring layer 33. The third wiring layer 33 is disposed on the surface 32A of the third semiconductor substrate 32 in the direction of arrow Z. The third semiconductor substrate 32 has a surface 32B in the opposite direction of arrow Z. The second substrate 20 is stacked on the surface 32A of the third semiconductor substrate 32, separated by the third wiring layer 33.

[0053] In the first embodiment, the third semiconductor substrate 32 uses a material similar to that of the first semiconductor substrate 12. That is, the third semiconductor substrate 32 is a single-crystal Si substrate.

[0054] Circuit 31 is disposed on surface 32A of third semiconductor substrate 32. Although detailed structure and description are omitted, semiconductor elements such as transistors Tr constituting one or both of the first readout circuit RE1 and the second readout circuit RE2 are disposed in circuit 31. The first readout circuit RE1 is electrically connected to the first photoelectric conversion element 11. The second readout circuit RE2 is electrically connected to the second photoelectric conversion element 21.

[0055] At least multiple layers of wiring 331 are arranged in the third wiring layer 33. These multiple layers of wiring 331 electrically connect components, etc. Here, the components are semiconductor components that form circuit 31. Wiring 331 uses a wiring material such as Cu. Wiring 331 is embedded in an insulating layer 335. In fact, the insulating layer 335 is formed by stacking multiple layers of insulating films. The insulating film is, for example, SiO2.

[0056] The uppermost wiring 331 on the second substrate 20 side of the third wiring layer 33 and the uppermost wiring 231 on the third substrate 30 side of the second wiring layer 23 are respectively used as terminals. These terminals are electrically connected to each other and mechanically joined. Since each of wirings 231 and 331 here is made of Cu, for example, wirings 231 and 331 are joined to each other by Cu-Cu bonding. [Manufacturing method of photodetector 1]

[0057] Next, refer to Figures 6 to 11The manufacturing method of the aforementioned photodetector 1 will be described. Figures 6 to 11 A series of process cross-sectional examples are shown to illustrate the manufacturing method of the photodetector 1 according to the first embodiment.

[0058] First, such as Figure 6 As shown, the second substrate 20 is stacked on the third substrate 30. (As described above) Figure 1 As shown, the third substrate 30 includes a third semiconductor substrate 32 and a third wiring layer 33; however, the third substrate 30 is shown here in a simplified manner. The second substrate 20 includes a second semiconductor substrate 22 and a second wiring layer 23. A second photoelectric conversion element 21 is formed in the second semiconductor substrate 22. In addition, wiring 231 and an insulating layer 235 are formed in the second wiring layer 23.

[0059] In the second substrate 20, an insulator 24 is formed on the surface 22A of the second semiconductor substrate 22 (see...). Figure 7 When forming the insulator 24, a second substrate 20 is formed, including the second semiconductor substrate 22, the second wiring layer 23 and the insulator 24. like Figure 7 As shown, a mask 7 is formed on the insulator 24. The mask 7 is an etching mask with openings in the formation region of the light-shielding body 6 (see reference). Figure 1 and Figure 3 Mask 7, for example, uses a photoresist.

[0060] like Figure 8 As shown, an etching process is performed using mask 7, and a trench 61 is formed in the second substrate 20. The trench 61 is formed to extend from the surface 24A of the insulator 24 through the insulator 24 and the second semiconductor substrate 22, reaching the depth of the wiring 231 of the second wiring layer 23. During the etching process, an anisotropic etching method, such as reactive ion etching (RIE), is used. Additionally, the wiring 231 serves as an etch stop layer to control the depth of the trench 61.

[0061] like Figure 9 As shown, the embedded part 62 is embedded in the trench 61. Here, the embedded part 62 includes a first embedded part 621 and a second embedded part 622. That is, firstly, the first embedded part 621 is formed along the inner wall of the trench 61, and then, the second embedded part 622 is formed in the trench 61 through the first embedded part 621 between the second embedded part 622 and the trench 61.

[0062] like Figure 10 As shown, unwanted embedded parts 62 formed on the surface 24A of the insulator 24 are removed. During removal, methods such as chemical mechanical polishing (CMP) or etching back are used. When the unwanted embedded part 62 is removed, a light-shielding body 6 is formed, including the groove 61 and the embedded part 62. The position of the end face 6A of the light-shielding body 6 in the direction of arrow Z coincides with the position of the surface 24A of the insulator 24.

[0063] like Figure 11 As shown, the first substrate 10 is layered on top of the second substrate 20 in the direction of arrow Z. Although detailed descriptions are omitted, as described above... Figure 1 As shown, the first substrate 10 includes a first semiconductor substrate 12 containing a first photoelectric conversion element 11 and a first wiring layer 13 located on the side of the second substrate 20 of the first semiconductor substrate 12.

[0064] As mentioned above Figure 1 As shown, an optical filter 4 is formed on the first photoelectric conversion element 11 in the first substrate 10, and an optical lens 5 is formed on the optical filter 4. After completing this series of processes, the above is finished. Figure 1 The photodetector 1 shown. [Functions and Effects]

[0065] As described above, the photodetector 1 according to the first embodiment includes, as follows: Figures 1 to 3 A first base 10 and a second base 20 are shown. The first substrate 10 includes a first semiconductor substrate 12, in which a first photoelectric conversion element 11 is disposed to convert incident light L into charge. The second substrate 20 is disposed on the side of the first substrate 10 opposite to the incident side of the incident light L, and includes a second semiconductor substrate 22, in which a second photoelectric conversion element 21 is disposed to convert incident light L into charge. The photodetector 1 also includes a light-shielding body 6. Viewed from the incident side of the incident light L, the light-shielding body 6 is arranged around the side of the second photoelectric conversion element 21. The light-shielding body 6 extends at least through the second semiconductor substrate 22 in the thickness direction from the surface 24A of the second substrate 20 (of the insulator 24) located on the incident side of the incident light L. The light-shielding body 6 blocks light from the second photoelectric conversion element 21. In the photodetector 1 with this configuration, a light-shielding body 6 is arranged around the side of the second photoelectric conversion element 21, and the light-shielding body 6 is formed to extend from the surface 24A of the second substrate 20 through the second semiconductor substrate 22. That is, in the second substrate 20, since the light-shielding body 6 is arranged to extend from the region around the side of the second photoelectric conversion element 21 to the first substrate 10, the path of light leakage Le between adjacent second photoelectric conversion elements 21, which is caused by the light generated by the second photoelectric conversion element 21, is blocked. The light generated by the second photoelectric conversion element 21 is also allowed to propagate to the first substrate 10 side, and is also reflected on the first substrate 10 side. The light-shielding body 6 can substantially reduce most of the light leakage Le between adjacent second photoelectric conversion elements 21. Therefore, color mixing between the second photoelectric conversion elements 21 arranged adjacent to each other can be effectively suppressed or prevented.

[0066] Furthermore, in photodetector 1, such as Figure 1 and Figure 3 As shown, the first substrate 10 includes a first wiring layer 13 on the second substrate 20 side of the first semiconductor substrate 12. The second substrate 22 includes an insulator 24 on the first substrate 10 side of the second semiconductor substrate 22. Furthermore, a light-shielding body 6 extends from the surface 24A of the insulator 24 located on the first substrate 10 side through the second semiconductor substrate 22. Therefore, in the second substrate 20, since the light-shielding body 6 is arranged from the second semiconductor substrate 22 to the surface 24A of the insulator 24, the path of light leakage Le between adjacent second photoelectric conversion elements 21 can be effectively reduced. Therefore, color mixing between adjacent second photoelectric conversion elements 21 can be effectively suppressed or prevented.

[0067] Furthermore, in photodetector 1, such as Figure 1 As shown, the second substrate 20 includes a second wiring layer 23 on the side of the second semiconductor substrate 22 opposite to the first substrate 10. The second wiring layer 23 includes wirings 231. Furthermore, the light shield 6 is arranged to extend to and reach the wirings 231 of the second wiring layer 23. Therefore, in the second substrate 20, since the light-shielding body 6 is arranged from the second semiconductor substrate 22 to the wiring 231 of the second wiring layer 23, the path of light leakage Le between adjacent second photoelectric conversion elements 21 can be effectively reduced on the second wiring layer 23 side. Therefore, color mixing between adjacent second photoelectric conversion elements 21 can be effectively suppressed or prevented.

[0068] Furthermore, in photodetector 1, such as Figure 1 and Figure 3As shown, the second photoelectric conversion element 21 is a SPAD, which multiplies the carriers generated by the photons of the incident light L. Therefore, leakage of adjacent carriers multiplied by the SPAD can be effectively suppressed or prevented between adjacent second photoelectric conversion elements 21. Here, in the photodetector 1, the first photoelectric conversion element 11 and the second photoelectric conversion element 21 are arranged coaxially with respect to the optical axis of the incident light L. Therefore, since a circuit structure that allows the two optical axes to coincide with each other is not required, the circuit structure of the first readout circuit RE1, the second readout circuit RE2, and subsequent circuits can be simplified.

[0069] In addition, such as Figure 1 As shown, the photodetector 1 includes a third substrate 30. The third substrate 30 is disposed on the side of the second substrate 20 opposite to the first substrate 10, and includes a third semiconductor substrate 32 on which a circuit 31 is mounted. The circuit 31 is electrically connected to at least one of the first photoelectric conversion element 11 and the second photoelectric conversion element 21. Therefore, a photodetector 1 comprising a first photoelectric conversion element 11, a second photoelectric conversion element 21, and a circuit 31 can be obtained, and color mixing between the second photoelectric conversion elements 21 arranged adjacent to each other can be effectively suppressed or prevented. <2. Second Embodiment>

[0070] Reference Figure 12 The photodetector 1 according to the second embodiment of this disclosure is described. It should be noted that in the second and subsequent embodiments, components that are the same or substantially the same as those in the photodetector 1 according to the first embodiment are indicated by the same reference numerals, and redundant descriptions will be omitted. [Construction of Photodetector 1]

[0071] Figure 12 An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the second embodiment is shown. like Figure 12 As shown, the photodetector 1 includes a second terminal 63 in the light shield 6. The second terminal 63 is disposed on the surface 24A of the insulator 24 in the second substrate 20 and is connected to the embedded part 62 of the light shield 6.

[0072] In the second embodiment, the second terminal 63 comprises the same material as the second embedded member 622 of the embedded member 62. Alternatively, the second terminal 63 may differ from the second embedded member 622, but may comprise one or more materials selected from the example materials of the second embedded member 622. In other words, the second terminal 63 is formed as part of the light-shielding body 6, and the light-shielding body 6 is configured to include the second terminal 63. Specifically, the surface side of the second terminal 63 located on the first substrate 10 side is formed as the end face 6A of the light-shielding body 6. The position of the end face 6A coincides with the position of the surface 24A of the insulator 24.

[0073] Furthermore, the width of the second terminal 63 is greater than the width of the groove 61 of the light-shielding body 6 in the same direction. Here, in the side view, the second terminal 63 is formed to protrude horizontally from the groove 61.

[0074] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the first embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0075] As described above, the photodetector 1 according to the second embodiment can achieve similar functions and effects as the photodetector 1 according to the first embodiment.

[0076] Additionally, in photodetector 1, such as Figure 12 As shown, the light-shielding body 6 includes a second terminal 63. The second terminal 63 is disposed on the surface (24A) side of the second substrate 20 and is connected to the embedded member 62. In addition, the width dimension of the second terminal 63 is larger than the width dimension of the groove 61 of the light-shielding body 6 in the same direction. Therefore, the path of light leakage Le between adjacent second photoelectric conversion elements 21, which is formed between them, is blocked. The second terminal 63 of the light shield 6 can improve the reduction rate of light leakage Le between adjacent second photoelectric conversion elements 21. Therefore, color mixing between the second photoelectric conversion elements 21 arranged adjacent to each other can be suppressed or prevented more effectively.

[0077] In this technology, the width of the second terminal 63 can be smaller than the width of the groove 61 of the light shield 6 in the same direction. <3. Third Embodiment>

[0078] Reference Figures 13 to 15 The photodetector 1 according to the third embodiment of this disclosure is described. [Construction of Photodetector 1]

[0079] Figure 13An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the third embodiment is shown. Figure 14 An example of a planar structure of the second photoelectric conversion element 21 and the light shield 6 of the photodetector 1 is shown.

[0080] like Figure 13 and Figure 14 As shown, in the photodetector 1, according to the second embodiment, the second terminal 63 of the light-shielding body 6 in the photodetector 1 is connected to the embedded member 62 via a plug conductor 64 between them. The plug conductor 64 is continuously arranged around the side of the second photoelectric conversion element 21. Additionally, like the second embedded part 622 of embedded part 62, the plug conductor 64 includes at least a light-shielding material.

[0081] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the second embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0082] As described above, the photodetector 1 according to the third embodiment can achieve similar functions and effects as the photodetector 1 according to the second embodiment. [Variation Example]

[0083] Figure 14 An example of the planar structure of the second photoelectric conversion element 21 and the light shield 6 of the photodetector 1 according to a variation of the third embodiment is shown. In the photodetector 1 according to this modified example, such as Figure 14 As shown, the plug conductors 64 are arranged discontinuously at equal intervals around the side of the second photoelectric conversion element 21. In other words, the plug conductors 64 are formed as dots in the plan view.

[0084] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the third embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0085] As described above, the photodetector 1 according to this modification can achieve similar functions and effects as the photodetector 1 according to the third embodiment. <4. Fourth Embodiment>

[0086] Reference Figure 16 The photodetector 1 according to the fourth embodiment of this disclosure is described. [Construction of Photodetector 1]

[0087] Figure 16An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the fourth embodiment is shown.

[0088] like Figure 16 As shown, in the photodetector 1 according to the third embodiment, the first substrate 10 of the photodetector 1 includes a first wiring layer 13 containing a first terminal 131P on the second substrate 20 side of the first semiconductor substrate 12. The first terminal 131P is formed by the uppermost wiring 131 on the second substrate 20 side of the first wiring layer 13. The second terminal 63 of the light-shielding body 6 of the second substrate 20 and the first terminal 131P are electrically connected and mechanically joined at the stacking interface (joining interface) between the first substrate 10 and the second substrate 20. When each of the second terminal 63 and the first terminal 131P includes, for example, Cu, the second terminal 63 and the first terminal 131P are joined to each other by Cu-Cu bonding.

[0089] When the embedded part 62 of the light-shielding body 6 includes a conductive material, the light-shielding body 6 can be used as a through wiring. That is, it is possible to provide signals or power between the first substrate 10 and the third substrate 30 through the light-shielding body 6.

[0090] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the third embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0091] As described above, the photodetector 1 according to the fourth embodiment enables it to achieve functions and effects similar to those achieved by the photodetector 1 according to the third embodiment. <5. Fifth Embodiment>

[0092] Reference Figure 17 The photodetector 1 according to the fifth embodiment of this disclosure is described. [Construction of Photodetector 1]

[0093] Figure 17 An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the fifth embodiment is shown.

[0094] like Figure 17 As shown, in the photodetector 1, the second terminal 63 of the light-shielding body 6 in the photodetector 1 according to the fourth embodiment is electrically conductive, and a portion of the second terminal 63 is arranged to extend as a lead wire. Here, the second terminal 63 is arranged as a lead wire extending from the end portion of the pixel region where a plurality of pixels 2 are arranged to the peripheral region of the photodetector 1. In addition, like the second terminal 63, the first terminal 131P is arranged to extend as a lead wire.

[0095] The lead-out wiring is electrically connected to an external terminal 8 arranged in the first wiring layer 13 of the first substrate 10 in the peripheral region of the photodetector 1. One end of the bonding wiring is electrically connected to the external terminal 8. The other end of the bonding wiring is electrically connected to an external device (not shown) or wiring board of the photodetector 1.

[0096] Alternatively, the lead-out wiring can be configured to be electrically connected to external terminals disposed on surface 32B of the third semiconductor substrate 32 of the third substrate 30. The electrical connection between the lead-out wiring and the external terminals can use through wiring with a structure similar to that of the light-shielding body 6. Furthermore, the external terminals are electrically connected to external devices or wiring boards (not shown) via microbump electrodes.

[0097] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the fourth embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0098] As described above, the photodetector 1 according to the fifth embodiment can achieve similar functions and effects as the photodetector 1 according to the fourth embodiment. <6. Sixth Embodiment>

[0099] Reference Figure 18 The photodetector 1 according to the sixth embodiment of this disclosure is described. [Construction of Photodetector 1]

[0100] Figure 18 An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the sixth embodiment is shown.

[0101] like Figure 18 As shown, in the photodetector 1, the light-shielding body 6 in the photodetector 1 according to the first embodiment is arranged to extend to a position before the wiring 231 of the second wiring layer 23 of the second substrate 20. Although not shown in detail, the insulating film of the insulating layer 235 is located between the end face 6B of the light-shielding body 6 and the wiring 231.

[0102] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the first embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0103] As described above, the photodetector 1 according to the sixth embodiment can achieve functions and effects similar to those achieved by the photodetector 1 according to the first embodiment. <7. Seventh Embodiment>

[0104] Reference Figure 19The photodetector 1 according to the seventh embodiment of this disclosure is described. [Construction of Photodetector 1]

[0105] Figure 19 An example of a vertical cross-sectional structure corresponding to a plurality of pixels 2 of the photodetector 1 according to the seventh embodiment is shown.

[0106] like Figure 19 As shown, in the photodetector 1, the light-shielding body 6 in the photodetector 1 according to the first embodiment is configured to extend from the second substrate 20 to the first substrate 10. That is, the light-shielding body 6 is arranged to extend from the surface 12A of the first semiconductor substrate 12 of the first substrate 10 through the first semiconductor substrate 12, the first wiring layer 13, the insulator 24 and the second semiconductor substrate 22 and reach the wiring 231 of the second wiring layer 23.

[0107] The components other than those described above are the same or substantially the same as those of the photodetector 1 according to the first embodiment described above, and therefore the description of the same components is omitted. [Functions and Effects]

[0108] As described above, the photodetector 1 according to the seventh embodiment can achieve similar functions and effects as the photodetector 1 according to the first embodiment.

[0109] Furthermore, in photodetector 1, such as Figure 19 As shown, since the light-shielding body 6 is arranged across the first substrate 10 and the second substrate 20, color mixing between the first photoelectric conversion element 11 and the second photoelectric conversion element 21 arranged adjacent to each other can be suppressed or prevented more effectively. <8. Practical Application Examples on Moving Bodies>

[0110] The technology based on this disclosure (the Technology) can be applied to a variety of products. For example, the Technology of this disclosure can be implemented as a device mounted on any type of mobile body. Examples of mobile bodies include automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobile devices, aircraft, drones, ships, and robots.

[0111] Figure 20 This is a block diagram illustrating a schematic construction example of a vehicle control system, which is an example of a mobile body control system to which the technology according to embodiments of the present disclosure can be applied.

[0112] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 20In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. Furthermore, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown as functional components of the integrated control unit 12050.

[0113] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 acts as a control device for devices such as: a drive force generating device (e.g., an internal combustion engine, drive motor, etc.) for generating vehicle driving force, a drive force transmission mechanism for transmitting driving force to the wheels, a steering mechanism for adjusting the vehicle's steering angle, and a braking device for generating vehicle braking force.

[0114] The body system control unit 12020 controls the operation of various devices installed on the vehicle body according to various programs. For example, the body system control unit 12020 acts as a control device for devices such as keyless entry systems, smart key systems, power windows, or various lights such as headlights, reversing lights, brake lights, turn signals, or fog lights. In this case, radio waves or signals from various switches transmitted from a portable device that serves as a key alternative can be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals and controls the vehicle's door locking devices, power windows, or lights, etc.

[0115] The exterior information detection unit 12030 detects external information about the vehicle, including the vehicle control system 12000. For example, the exterior information detection unit 12030 is connected to the imaging unit 12031. The exterior information detection unit 12030 causes the imaging unit 12031 to image the exterior of the vehicle and receives the captured images. Based on the received images, the exterior information detection unit 12030 can perform processing for detecting objects such as people, vehicles, obstacles, signs, or characters on the road surface, or processing for detecting their distances.

[0116] 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 may also output an electrical signal as an image, or an electrical signal as distance measurement information. Furthermore, the light received by the imaging unit 12031 can be visible light, or it may be invisible light such as infrared light.

[0117] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. For example, the in-vehicle information detection unit 12040 is connected to a driver state detection unit 12041 for detecting the driver's state. The driver state detection unit 12041 includes, for example, a camera for imaging the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or the driver's concentration level, or it can determine whether the driver is dozing off.

[0118] The microcomputer 12051 can calculate target control values ​​for the drive force generating device, steering mechanism, or braking device based on information about the vehicle's interior and exterior obtained by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform coordinated control to realize functions of advanced driver assistance systems (ADAS), including collision avoidance or shock absorption, following distance-based driving, speed maintenance driving, collision warning, or lane departure warning.

[0119] In addition, based on the environmental information about the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, the microcomputer 12051 can perform coordinated control for autonomous driving by controlling the drive force generating device, steering mechanism or braking device, etc., which enables the vehicle to drive automatically without relying on the driver's operation.

[0120] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12030 based on external information about the vehicle acquired by the external information detection unit 12030. For example, the microcomputer 12051 can perform coordinated control aimed at preventing glare by controlling the headlights to switch from high beams to low beams, for example, based on the position of the vehicle in front or oncoming vehicles detected by the external information detection unit 12030.

[0121] The sound / image output unit 12052 transmits an output signal of at least one of sound and image to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle. Figure 20 In the example, audio speaker 12061, display unit 12062, and instrument panel 12063 are shown as output devices. Display unit 12062 may include, for example, at least one of a vehicle display and a head-up display.

[0122] Figure 21 This is a diagram showing an example of the mounting position of the imaging unit 12031.

[0123] exist Figure 21In the imaging unit 12031, there are imaging units 12101, 12102, 12103, 12104 and 12105.

[0124] Imaging units 12101, 12102, 12103, 12104, and 12105 are installed in locations such as the front nose, rearview mirrors, rear bumper, rear door, and upper part of the interior windshield of vehicle 12100. Imaging unit 12101 at the front nose and imaging unit 12105 at the upper part of the interior windshield primarily acquire images of the front of vehicle 12100. Imaging units 12102 and 12103 at the rearview mirrors primarily acquire images of the sides of vehicle 12100. Imaging unit 12104 at the rear bumper or rear door primarily acquires images of the rear of vehicle 12100. Imaging unit 12105 at the upper part of the interior windshield is primarily used to detect vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes ahead.

[0125] Notice, Figure 21 Examples of the imaging ranges of imaging units 12101 to 12104 are shown. Imaging range 12111 represents the imaging range of imaging unit 12101 located at the front nose. Imaging ranges 12112 and 12113 represent the imaging ranges of imaging units 12102 and 12103 located at the rearview mirrors, respectively. Imaging range 12114 represents the imaging range of imaging unit 12104 located at the rear bumper or rear door. For example, a bird's-eye view image of vehicle 12100 is obtained by overlaying image data captured by imaging units 12101 to 12104.

[0126] At least one of the imaging units 12101 to 12104 may have the function of obtaining distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

[0127] For example, the microcomputer 12051 can determine the distance and time-varying distance (relative speed to the vehicle 12100) of each three-dimensional object within the imaging range 12111 to 12114 based on distance information obtained from the imaging units 12101 to 12104, and extract the nearest three-dimensional object as the preceding vehicle, specifically existing on the driving path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., equal to or greater than 0 km / h). Furthermore, the microcomputer 12051 can pre-set a following distance to be maintained in front of the preceding vehicle and execute automatic braking control (including follow-stop control), automatic acceleration control (including follow-start control), etc. Therefore, coordinated control for autonomous driving can be performed, enabling the vehicle to drive automatically without relying on driver operation, etc.

[0128] For example, microcomputer 12051 can classify three-dimensional object data of three-dimensional objects into two-wheeled vehicles, standard-sized vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from imaging units 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic obstacle avoidance. For example, microcomputer 12051 identifies obstacles around vehicle 12100 as obstacles that can be visually recognized by the driver of vehicle 12100 and obstacles that are difficult to visually recognize by the driver of vehicle 12100. Then, microcomputer 12051 determines a collision risk to indicate the risk of collision with each obstacle. If the collision risk is equal to or higher than a set value and therefore there is a possibility of collision, microcomputer 12051 outputs a warning to the driver through audio speaker 12061 or display unit 12062, and executes forced deceleration or evasive steering through driving system control unit 12010. Microcomputer 12051 can thus assist driving to avoid collisions.

[0129] At least one of the imaging units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the images captured by the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by extracting feature points from the images captured by the imaging units 12101 to 12104, which are infrared cameras; and by performing pattern matching processing on a series of feature points representing the outline of an object to determine whether it is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 to overlay a square outline for emphasis on the identified pedestrian. In addition, the sound / image output unit 12052 can control the display unit 12062 to display icons or the like for indicating pedestrians at a desired location.

[0130] The foregoing describes an example of a vehicle control system to which the technology according to this disclosure can be applied. The technology according to this disclosure can be applied to the imaging unit 12031 in the above-described configuration. By applying the technology according to this disclosure to the imaging unit 12031, it is possible to realize an imaging unit 12031 capable of effectively suppressing or preventing color mixing between adjacent photoelectric conversion elements. <9. Other Embodiments>

[0131] This technology is not limited to the above embodiments, and various modifications can be made without departing from its spirit. For example, among the photodetectors according to the first to seventh embodiments described above, photodetectors according to two or more embodiments can be combined.

[0132] A photodetector according to a first embodiment of the present disclosure includes a first substrate and a second substrate. The first substrate includes a first semiconductor substrate, in which a first photoelectric conversion element is disposed. The first photoelectric conversion element converts incident light into electrical charge. The second substrate is disposed on the side of the first substrate 10 opposite to the light incident side and includes a second semiconductor substrate, in which a second photoelectric conversion element is disposed. The second photoelectric conversion element converts incident light into electrical charge. The photodetector also includes a light-shielding element. When viewed from the light-incident side, the light-shielding element is arranged around the side of the second photoelectric conversion element. The light-shielding element extends at least through the second semiconductor substrate along the thickness direction from the light-incident surface of the second substrate. The light-shielding element blocks light from the second photoelectric conversion element. A photodetector with this structure can effectively suppress or prevent color mixing between second photoelectric conversion elements arranged adjacent to each other.

[0133] In the photodetector according to the second embodiment of this disclosure, the first photoelectric conversion element in the photodetector according to the first embodiment includes a photodiode. Additionally, the second photoelectric conversion element includes an avalanche diode, which multiplies the carriers generated by photons of incident light. Photodetectors with this configuration can effectively suppress or prevent leakage of carriers, especially those multiplied by avalanche diodes, between adjacent second photoelectric conversion elements.

[0134] The photodetector according to the third embodiment of this disclosure further includes a third substrate in the photodetector according to the first or second embodiment. The third substrate is disposed on the side of the second substrate opposite to the first substrate and includes a third semiconductor substrate on which circuitry is mounted. The circuitry is electrically connected to at least one of the first and second photoelectric conversion elements. A photodetector comprising a first photoelectric conversion element, a second photoelectric conversion element, and a circuit can be obtained, and color mixing between second photoelectric conversion elements arranged adjacent to each other can be effectively suppressed or prevented. <Construction of this technology>

[0135] This technology has any of the following structures. According to this technology having any of the following structures, color mixing between photoelectric conversion elements arranged adjacent to each other in a photodetector can be effectively suppressed or prevented.

[0136] (1) A photodetector, comprising: A first substrate, the first substrate including a first semiconductor substrate, wherein a first photoelectric conversion element for converting incident light into charge is disposed in the first semiconductor substrate; A second substrate, disposed on the side of the first substrate opposite to the light incident side, includes a second semiconductor substrate, in which a second photoelectric conversion element for converting incident light into electrical charge is disposed; and A light-shielding body, when viewed from the light-incident side, is arranged around the side of the second photoelectric conversion element. The light-shielding body extends at least through the second semiconductor substrate in the thickness direction from the surface of the second substrate located on the light-incident side, and blocks light from the second photoelectric conversion element. (2) According to the photodetector described in (1) above, wherein, The first substrate includes a first wiring layer located on the second substrate side of the first semiconductor substrate. The second substrate includes an insulator located on the first substrate side of the second semiconductor substrate, and The light-shielding body extends from the surface of the first substrate side of the insulator through the second semiconductor substrate. (3) The photodetector according to (1) or (2) above, wherein, The second substrate includes a second wiring layer located on the side of the second semiconductor substrate opposite to the first substrate, the second wiring layer including wiring, and The light-shielding body is arranged to extend to a position before the wiring of the second wiring layer. (4) The photodetector according to (1) or (2) above, wherein, The second substrate includes a second wiring layer located on the side of the second semiconductor substrate opposite to the first substrate, the second wiring layer including wiring, and The light-shielding body is arranged to extend to and reach the wiring of the second wiring layer. (5) The photodetector according to any one of (1) to (4) above, wherein, The light-shielding body has grooves and includes embedded parts. The trench is provided at least along the thickness direction of the second semiconductor substrate. The embedded part is embedded in the trench and has light-shielding properties. (6) The photodetector according to (5) above, wherein the embedded member comprises: A first embedded part, wherein the first embedded part is disposed along the inner wall of the trench, and The second embedded part is embedded in the trench, with the first embedded part in between. (7) The photodetector according to (6) above, wherein, The first embedded component includes an embedding blocking metal or an embedding insulator, and The second embedded component comprises one or more metals selected from Cu, W, Al, Ag, Ta and Co, or an alloy formed by combining two or more metals selected from Cu, W, Al, Ag, Ta and Co. (8) The photodetector according to any one of (5) to (7) above, wherein the light shield further includes a second terminal disposed on the surface side of the second substrate and connected to the embedded member. (9) The photodetector according to (8) above, wherein the width dimension of the second terminal is greater than the width dimension of the trench in the same direction. (10) The photodetector according to (8) or (9) above, wherein the second terminal is conductive and a portion of the second terminal is arranged as a lead wire extension. (11) The photodetector according to any one of (8) to (10) above, wherein, The first substrate includes a first wiring layer located on the second substrate side of the first semiconductor substrate, the first wiring layer including a first terminal, and The second terminal is engaged with the first terminal. (12) The photodetector according to any one of (8) to (11) above, wherein the second terminal is connected to the embedded part through the plug electrical conductor. (13) The photodetector according to (12) above, wherein the plug electrical conductor is continuously arranged around the side of the second photoelectric conversion element. (14) The photodetector according to (12) above, wherein the plug electrical conductor is intermittently arranged around the side of the second photoelectric conversion element. (15) The photodetector according to any one of (1) to (14) above, wherein, The first photoelectric conversion element includes a photodiode, and The second photoelectric conversion element includes an avalanche diode that multiplies the charge carriers generated by photons of incident light. (16) The photodetector according to any one of (1) to (15) above further includes a third substrate disposed on the side of the second substrate opposite to the first substrate, and the third substrate includes a third semiconductor substrate on which a circuit is mounted, the circuit being electrically connected to at least one of the first photoelectric conversion element and the second photoelectric conversion element.

[0137] Those skilled in the art will understand that various modifications, combinations, sub-combinations and alterations can be made according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents.

Claims

1. A photodetector, comprising: A first substrate, the first substrate including a first semiconductor substrate, wherein a first photoelectric conversion element for converting incident light into charge is disposed in the first semiconductor substrate; The second substrate is disposed on the side of the first substrate opposite to the light incident side, and includes a second semiconductor substrate in which a second photoelectric conversion element for converting incident light into charge is disposed; as well as A light-shielding body, when viewed from the light-incident side, is arranged around the side of the second photoelectric conversion element. The light-shielding body extends at least through the second semiconductor substrate in the thickness direction from the surface of the second substrate located on the light-incident side, and blocks light from the second photoelectric conversion element.

2. The photodetector according to claim 1, wherein, The first substrate includes a first wiring layer located on the second substrate side of the first semiconductor substrate. The second substrate includes an insulator located on the first substrate side of the second semiconductor substrate, and The light-shielding body extends from the surface of the first substrate side of the insulator through the second semiconductor substrate.

3. The photodetector according to claim 1, wherein, The second substrate includes a second wiring layer located on the side of the second semiconductor substrate opposite to the first substrate, the second wiring layer including wiring, and The light-shielding body is arranged to extend to a position before the wiring of the second wiring layer.

4. The photodetector according to claim 1, wherein, The second substrate includes a second wiring layer located on the side of the second semiconductor substrate opposite to the first substrate, the second wiring layer including wiring, and The light-shielding body is arranged to extend to and reach the wiring of the second wiring layer.

5. The photodetector according to claim 1, wherein, The light-shielding body has grooves and includes embedded parts. The trench is provided at least along the thickness direction of the second semiconductor substrate. The embedded part is embedded in the trench and has light-shielding properties.

6. The photodetector according to claim 5, wherein, The embedded component includes: A first embedded part, wherein the first embedded part is disposed along the inner wall of the trench, and The second embedded part is embedded in the trench, with the first embedded part in between.

7. The photodetector according to claim 6, wherein, The first embedded component includes an embedding blocking metal or an embedding insulator, and The second embedded component comprises one or more metals selected from Cu, W, Al, Ag, Ta and Co, or an alloy formed by combining two or more metals selected from Cu, W, Al, Ag, Ta and Co.

8. The photodetector according to claim 5, wherein, The light-shielding body also includes a second terminal, which is disposed on the surface side of the second substrate and connected to the embedded part.

9. The photodetector according to claim 8, wherein, The width of the second terminal is greater than the width of the groove in the same direction.

10. The photodetector according to claim 8, wherein, The second terminal is conductive, and a portion of the second terminal is arranged as a lead wire extension.

11. The photodetector according to claim 8, wherein, The first substrate includes a first wiring layer located on the second substrate side of the first semiconductor substrate, the first wiring layer including a first terminal, and The second terminal is engaged with the first terminal.

12. The photodetector according to claim 8, wherein, The second terminal is connected to the embedded part through the plug conductor.

13. The photodetector according to claim 12, wherein, The plug conductors are continuously arranged around the side of the second photoelectric conversion element.

14. The photodetector according to claim 12, wherein, The plug conductors are intermittently arranged around the side of the second photoelectric conversion element.

15. The photodetector according to claim 1, wherein, The first photoelectric conversion element includes a photodiode, and The second photoelectric conversion element includes an avalanche diode that multiplies the charge carriers generated by photons of incident light.

16. The photodetector of claim 1, further comprising a third substrate disposed on the side of the second substrate opposite to the first substrate, and the third substrate comprising a third semiconductor substrate on which a circuit is mounted, the circuit being electrically connected to at least one of the first photoelectric conversion element and the second photoelectric conversion element.

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