Sensor chips, electronic devices and distance measuring devices

Abstract

A sensor chip according to an embodiment of the present invention includes pixels, each of which includes: a photoelectric conversion unit, the photoelectric conversion unit having a light incident surface on which light is incident and a multiplication region for multiplying carrier avalanches using a high electric field region; a light reflecting unit, the light reflecting unit being arranged to be opposite to a surface on the opposite side of the light incident surface of the photoelectric conversion unit; and a light focusing unit, the light focusing unit being arranged between the photoelectric conversion unit and the light reflecting unit.

Description

Technical Field

[0001] The present disclosure relates to, for example, a sensor chip having an avalanche photodiode, an electronic device including the sensor chip, and a distance measuring device. Background Art

[0002] Avalanche photodiode (APD) is a photodiode in which a high electric field region is provided in the depletion layer that expands due to the application of a predetermined reverse voltage to the pn junction. By forming a high electric field region, avalanche multiplication (avalanche breakdown) can occur, which involves a repetitive process in which carriers (electrons) generated by the photoelectric effect are accelerated by the electric field and cause impact ionization.

[0003] APDs can be driven in a linear mode near the breakdown voltage, and can also be driven in a Geiger mode at a voltage above the breakdown voltage. Geiger mode APDs are also called single photon avalanche diodes (SPADs), and can detect a single photon entering the photodiode.

[0004] Patent Document 1 discloses a sensor chip in which pixels including avalanche photodiodes are arranged in an array.

[0005] Citation list

[0006] Patent Literature

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-88488 Summary of the invention

[0008] Regarding sensors including SPADs, it is desired to improve PDE (Photon Detection Efficiency).

[0009] It is desirable to provide a sensor chip including a SPAD and capable of improving PDE, an electronic device including such a sensor chip, and a distance measuring device including such a sensor chip.

[0010] A sensor chip according to an embodiment of the present disclosure includes a pixel, wherein the pixel includes a photoelectric conversion unit, a light reflecting unit, and a light collecting unit. The photoelectric conversion unit includes a light incident surface on which light is incident and a multiplication region that multiplies carrier avalanches through a high electric field region. The light reflecting unit is arranged to be opposite to a surface on the opposite side of the light incident surface of the photoelectric conversion unit. The light collecting unit is arranged between the photoelectric conversion unit and the light reflecting unit.

[0011] An electronic device according to an embodiment of the present disclosure includes an optical system, a sensor chip, and a signal processing circuit, and includes the sensor chip according to the embodiment of the present disclosure described above as a sensor chip.

[0012] A distance measuring device according to an embodiment of the present disclosure includes an optical system, a sensor chip, and a signal processing circuit that calculates a distance to a measurement target based on an output signal of the sensor chip, and includes the sensor chip according to an embodiment of the present disclosure described above as a sensor chip.

[0013] In the sensor chip according to the embodiment of the present disclosure, the electronic device according to the embodiment, and the distance measuring device according to the embodiment, the light focusing section is provided between the photoelectric conversion section and the light reflecting section, thereby focusing the light passing through the photoelectric conversion section toward the light reflecting section. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram showing an example of a cross-sectional configuration of a sensor chip according to an embodiment of the present disclosure.

[0015] Figure 2 It is shown Figure 1 A diagram showing an example of a planar configuration of a diffractive lens of a sensor chip is shown.

[0016] Figure 3 : is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification A.

[0017] Figure 4 : is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification B.

[0018] Figure 5 is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification C.

[0019] Figure 6 : is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification D.

[0020] Figure 7 : is a diagram showing an example of a cross-sectional structure of a sensor chip according to Modification E.

[0021] Figure 8 It is shown Figure 7 FIG. 1 is a diagram showing an example of a planar structure of a contact layer of a sensor chip.

[0022] Fig. 9 : is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification F.

[0023] Fig.10 : is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification G.

[0024] Fig.11 is a diagram showing an example of a cross-sectional configuration of a sensor chip according to Modification H.

[0025] Fig.12 : is a diagram showing an example of a cross-sectional structure of a sensor chip according to modification example 1.

[0026] Fig.13 : is a diagram showing an example of a cross-sectional structure of a sensor chip according to Modification Example J.

[0027] Fig.14 : is a block diagram showing an example of a schematic configuration of an electronic device including the sensor chip according to any of the above-described embodiments and their modified examples.

[0028] Fig.15 is a block diagram showing an example of a schematic configuration of a vehicle control system.

[0029] Fig.16 It is a diagram for assisting in explaining an example of the installation positions of the vehicle exterior information detection unit and the imaging unit. DETAILED DESCRIPTION

[0030] In the following, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. Note that the description is given in the following order.

[0031] 1. Embodiment (sensor chip)... Figure 1 and Figure 2

[0032] An example of a diffractive lens in which a laminated body including an insulating film and a conductive film is provided between a SPAD and a light reflecting film.

[0033] 2. Modification (Sensor Chip)

[0034] Modification A: Example in which the diffractive lens includes an insulating film embedded in a groove of a semiconductor substrate ... Figure 3

[0035] Modification B: Example in which the diffractive lens includes a conductive film or an insulating film ... Figure 4

[0036] Modification C: An example in which an inner lens is provided between the SPAD and the light reflecting film... Figure 5

[0037] Modification D: Example in which the diffractive lens includes a first wiring line ... Figure 6

[0038] Modification E: Example in which a contact layer is provided in each first wiring included in the diffractive lens ... Figure 7 and Figure 8

[0039] Modification F: Example in which the cathode of the SPAD is provided in the middle of the pixel... Fig. 9

[0040] Modification G: An example in which a light reflecting film is provided on the second wiring and the light reflecting film is opposite to a part of the pixel (including the center of the pixel) ... Fig.10

[0041] Modification H: An example in which a light reflecting film is provided on the first wiring and the light reflecting film is opposite to a part of the pixel (including the center of the pixel) ... Fig.11

[0042] Modification I: Example in which the light incident surface has no irregularities... Fig.12

[0043] Modification J: Example without on-chip lens... Fig.13

[0044] 3. Application example: An example in which the sensor chip according to any one of the above-mentioned embodiments and their modified examples is applied to an electronic device... Fig.14

[0045] 4. Application example: An example in which the sensor chip according to any one of the above-mentioned embodiments and their modified examples is applied to a moving object... Fig.15 and Fig.16

[0046] 5. Other variations

[0047] <1. Example>

[0048] [Construction example]

[0049] Figure 1 An example of a cross-sectional configuration of a sensor chip 1 according to an embodiment of the present disclosure is shown. The sensor chip 1 includes a pixel array in which two or more pixels P are arranged in an array. The pixel P corresponds to a specific example of a "pixel" of the present disclosure.

[0050] Each pixel P has a structure in which a SPAD 2 and a wiring layer 26 are stacked. The wiring layer 26 includes a light reflecting film LR, and a diffraction lens DL is provided between the SPAD 2 and the light reflecting film LR. The SPAD 2 corresponds to a specific example of a “photoelectric conversion unit” of the present disclosure. The light reflecting film LR corresponds to a specific example of a “light reflecting unit” of the present disclosure. The diffraction lens DL corresponds to a specific example of a “light focusing unit” of the present disclosure.

[0051] The sensor chip 1 is a back-illuminated sensor chip that detects light incident from the back side of the semiconductor substrate 10. The SPAD 2 is provided in the semiconductor substrate 10 and includes a multiplication region MR in which a high electric field region avalanches carriers (electrons). The SPAD 2 includes a light incident surface 10A. One surface of the semiconductor substrate 10 corresponds to the light incident surface 10A of the SPAD 2. The light incident surface 10A is a surface obtained by grinding the back side of the semiconductor substrate 10. The light incident surface 10A is also referred to as the back side of the semiconductor substrate 10. In addition, the other surface of the semiconductor substrate 10 (the surface on the opposite side of the light incident surface 10A) is also referred to as the surface 10C of the semiconductor substrate 10. The light reflecting film LR is provided in a manner opposite to the surface 10C of the semiconductor substrate 10.

[0052] The semiconductor substrate 10 is provided with a pixel separation groove 30 for separating adjacent pixels P. A pixel separation film TI is embedded in the pixel separation groove 30. The pixel separation film TI has, for example, a stacked structure of an insulating film 31 and a light-shielding metal film 32. The insulating film 31 includes silicon oxide (SiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), aluminum oxide (Al2O3), etc. The metal film 32 includes tungsten (W), aluminum (Al), etc. In addition, a gap V is provided inside the metal film 32. Therefore, adjacent pixels P are electrically and optically separated from each other. Note that it is not necessary to provide a gap V inside the metal film 32.

[0053] Now, the SPAD 2 provided in the semiconductor substrate 10 is described. A well layer 11 is provided in a region of the semiconductor substrate 10 separated by the pixel separation film TI. In the well layer 11, a p-type semiconductor region 14 on the light incident surface 10A side and an n-type semiconductor region 15 on the surface 10C side of the semiconductor substrate 10 are provided in a manner to provide a pn junction. The cathode 16 is provided in a manner extending from the n-type semiconductor region 15 to the surface 10C side of the semiconductor substrate 10. In addition, a pinning layer 12 is provided between the side surface of the well layer 11 and the pixel separation film TI. The pinning layer 12 is a p-type semiconductor region. An anode 13 is provided at the end of the pinning layer 12 on the surface 10C side of the semiconductor substrate 10. The anode 13 is a p-type semiconductor region.

[0054] The semiconductor substrate 10 includes, for example, silicon (Si). The well layer 11 may be an n-type semiconductor region or a p-type semiconductor region. Preferably, the well layer 11 has, for example, a thickness of about 1×10 14 Atom / cm -3 The low concentration n-type or p-type semiconductor region below makes the well layer 11 more easily depleted, thereby improving the PDE of the SPAD 2.

[0055] The p-type semiconductor region 14 is a p-type semiconductor region (p+) having a high impurity concentration. The n-type semiconductor region 15 is an n-type semiconductor region (n+) having a high impurity concentration.

[0056] The cathode 16 is an n-type semiconductor region (n++) having a high impurity concentration. The cathode 16 is connected to the n-type semiconductor region 15 and is provided so as to be able to apply a predetermined bias voltage to the n-type semiconductor region 15 .

[0057] The pinning layer 12 is a p-type semiconductor region (p). The pinning layer 12 is arranged in a manner that surrounds the side of the well layer 11 along the pixel separation film TI. The pinning layer 12 accumulates holes. The anode 13 is connected to the pinning layer 12, and it is possible to adjust the bias voltage from the anode 13. This increases the hole concentration of the pinning layer 12, thereby making the pinning stronger. Therefore, the generation of dark current, such as that generated at the interface between the pixel separation film TI and the well layer 11, can be suppressed. The pinning layer 12 can, for example, have a structure in which a p-type semiconductor region (p+) and a p-type semiconductor region (p) are stacked in sequence when viewed from the pixel separation film TI.

[0058] The anode 13 is a p-type semiconductor region (p++) having a high impurity concentration. The anode 13 is connected to the pinned layer 12 and is provided so as to be able to apply a predetermined bias voltage to the pinned layer 12 .

[0059] The SPAD 2 is constructed in such a manner that applying a high negative voltage to the anode 13 causes a predetermined reverse voltage to be applied to the pn junction, which causes a depletion layer to expand from the pn junction of the p-type semiconductor region 14 and the n-type semiconductor region 15, thereby forming a high electric field region. When the high electric field region is formed, a multiplication region MR capable of avalanche multiplication of carriers is formed. Since avalanche multiplication occurs in the multiplication region MR, the SPAD 2 is capable of multiplying carriers generated by a single photon incident from the light incident surface 10A and detecting the multiplied carriers. The SPAD 2 is constructed as described above.

[0060] A second concavo-convex portion 10D is provided on the surface 10C (the surface on the opposite side of the light incident surface 10A) of the semiconductor substrate 10 (the first concavo-convex portion 10B will be described later). The second concavo-convex portion 10D includes a laminate of an insulating film 20 and a conductive film 21. For example, the insulating film 20 includes silicon oxide, and the conductive film 21 includes polycrystalline silicon. The insulating film 20 and the conductive film 21 are respectively formed of the same layers as the gate insulating film and the gate electrode of a MOS (Metal-Oxide-Semiconductor) transistor provided in a region of the semiconductor substrate 10 where no pixel P is provided.

[0061] Figure 2An example of a planar configuration of a diffraction lens DL of a sensor chip 1 is shown. A laminate of an insulating film 20 and a conductive film 21 provides a second concave-convex portion 10D having irregularities periodically formed in a concentric circle shape. The second concave-convex portion 10D corresponds to a specific example of a “second concave-convex portion” of the present disclosure. The second concave-convex portion 10D serves as a diffraction lens DL. The diffraction lens DL is an optical component that diffracts light to achieve the same effect as a lens. The diffraction lens DL is configured to include fine irregularities having a size of approximately the wavelength of light and periodically arranged in a concentric circle shape.

[0062] like Figure 1 As shown, the sidewall insulating film 22 is provided in a manner covering the sidewall of the conductive film 21 and the surface 10C of the semiconductor substrate 10. For example, the sidewall insulating film 22 includes silicon nitride. The passivation insulating film 23 is provided in a manner covering the conductive film 21 and the sidewall insulating film 22. For example, the passivation insulating film 23 includes silicon oxide.

[0063] The wiring layer 26 is provided in a manner covering the passivation insulating film 23. The wiring layer 26 includes two or more laminated wirings embedded in the insulating film 24. The two or more wirings include, for example, a first wiring 25B, a second wiring 25D, and a third wiring 25F. Note that although Figure 1 An example of stacked wiring including three layers is shown, but the number of layers of the stacked wiring is not particularly limited. Two or more wirings are connected by a contact layer 25A, a first vertical connection layer 25C and a second vertical connection layer 25E. The first wiring 25B, the second wiring 25D, the third wiring 25F, the contact layer 25A, the first vertical connection layer 25C and the second vertical connection layer 25E each include a metal film of copper or the like. The insulating film 24 includes, for example, silicon oxide. Although the insulating film 24 is shown as a single layer in the figure, it is a stack of insulating films corresponding to the layers of two or more wirings. The contact layer 25A is arranged in a manner that passes through the sidewall insulating film 22 and the passivation insulating film 23 and connects the anode 13 or the cathode 16 to the first wiring 25B. The two or more wirings embedded in the wiring layer 26 are configured to be able to apply a predetermined bias voltage to the anode 13 and the cathode 16, respectively. The portion of the first wiring 25B opposite to the SPAD 2 is used as a light reflection film LR. The light reflection film LR is configured to reflect light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 back toward the SPAD 2. The third wiring 25F is exposed from the insulating film 24 and functions as a terminal for external connection.

[0064] A first concave-convex portion 10B is provided on the back side of the semiconductor substrate 10 (the light incident surface 10A of the SPAD 2). The first concave-convex portion 10B corresponds to a specific example of the "first concave-convex portion" of the present disclosure. The first concave-convex portion 10B includes, for example, a quadrangular pyramid concave shape (an inverted pyramid shape) arranged in an array. The first concave-convex portion 10B diffuses the light by diffracting and scattering the light incident to the SPAD 2. By diffusing the incident light L, the optical path length in the SPAD 2 can be increased, thereby improving the PDE. The first concave-convex portion 10B is formed, for example, by etching the light incident surface 10A of the semiconductor substrate 10.

[0065] An inter-pixel light shielding film 33 is provided on the back side of the semiconductor substrate 10, and the inter-pixel light shielding film 33 is in contact with the pixel separation film TI. The inter-pixel light shielding film 33 includes, for example, a light shielding metal such as W or Al. The inter-pixel light shielding film 33 is configured to help prevent light obliquely incident on the light incident surface 10A from being incident on the pixel P to be incident on and from being incident on another pixel P adjacent thereto.

[0066] The anti-reflection film 35 is arranged in a manner that follows the irregularity of the first concavo-convex shape portion 10B and covers the light incident surface 10A of the SPAD 2. For example, as the anti-reflection film 35, an insulating film having a stacked structure in which a fixed charge film and an oxide film are stacked and having a high dielectric constant (High-k) provided by an ALD (Atomic Layer Deposition) method can be used. For example, the anti-reflection film 35 includes a stack of a first anti-reflection film 35A, a second anti-reflection film 35B, and a third anti-reflection film 35C. The first anti-reflection film 35A, the second anti-reflection film 35B, and the third anti-reflection film 35C include, for example, hafnium oxide, aluminum oxide, titanium oxide (TiO2) or STO (Strontium Titan Oxide: strontium titanium oxide), respectively. For example, a structure in which the first anti-reflection film 35A includes hafnium oxide, the second anti-reflection film 35B includes aluminum oxide, and the third anti-reflection film 35C includes silicon oxide can be used. The second anti-reflection film 35B is provided in the same layer as the insulating film 31 included in the pixel separation film TI. In addition, the third anti-reflection film 35C is provided on the entire surface and covers the inter-pixel light shielding film 33 .

[0067] In addition, on the back side of the semiconductor substrate 10, an on-chip lens 34 is provided in the upper layer of the anti-reflection film 35 in such a manner as to cover the light incident surface 10A. The on-chip lens 34 includes, for example, a light-transmitting material such as a thermoplastic positive photosensitive resin or silicon nitride. The on-chip lens 34 is configured to converge the incident light L incident on the light incident surface 10A to the multiplication region MR. A protective film 36 is provided on the entire surface of the upper layer of the on-chip lens 34.

[0068] [Manufacturing method]

[0069] Next, the manufacturing process of the sensor chip 1 is described. For example, by ion implantation, the well layer 11, the pinning layer 12, the anode 13, the p-type semiconductor region 14, the n-type semiconductor region 15, the cathode 16, and the p-type semiconductor region 17 are formed on the semiconductor substrate 10. Then, for example, by a CVD (Chemical Vapor Deposition) method, an insulating film 20 and a conductive film 21 are formed on the surface 10C of the semiconductor substrate 10, and the insulating film 20 and the conductive film 21 are etched into a concentric shape to form a second concave-convex shape portion 10D (diffraction lens DL). Next, a sidewall insulating film 22 and a passivation insulating film 23 are formed. After that, the insulating film and the conductive film are repeatedly formed to form a wiring layer 26. Next, on the back surface of the semiconductor substrate 10, grinding of the semiconductor substrate 10 (forming the light incident surface 10A), formation of the pixel separation film TI, formation of the first concavo-convex shape portion 10B, formation of the anti-reflection film 35, formation of the inter-pixel light shielding film 33, formation of the on-chip lens 34, and formation of the protective film 36 are performed. Thus, the sensor chip 1 is manufactured.

[0070] [operate]

[0071] In the sensor chip 1, in the SPAD 2 of each pixel P, a high negative voltage is applied to the anode 13, thereby applying a predetermined reverse voltage to the pn junction. This causes the depletion layer to expand from the pn junction of the p-type semiconductor region 14 and the n-type semiconductor region 15, thereby providing a high electric field region. The obtained high electric field region provides a multiplication region MR capable of avalanche multiplication of carriers. The multiplication region MR multiplies the carriers generated by a single photon incident from the light incident surface 10A to generate a multiplied signal charge. The obtained signal charge is extracted from the SPAD 2 and signal processing is performed by a signal processing circuit.

[0072] The sensor chip 1 can be used as a distance measuring sensor based on the ToF (Time of Flight) method. In the ToF method, the signal delay time between the signal based on the signal charge and the reference signal is converted into the distance to the measurement target. The signal processing circuit calculates the signal delay time based on the signal based on the signal charge obtained from the SPAD 2 of each pixel P and the reference signal, for example. The obtained signal delay time is converted into a distance. Therefore, the distance to the measurement target is measured.

[0073] [Function and Effect]

[0074] The sensor chip 1 of this embodiment includes a diffraction lens DL arranged between the SPAD 2 and the light reflecting film LR, and can focus the light incident from the light incident surface 10A, passing through the SPAD 2 without being photoelectrically converted and reaching the surface 10C side of the semiconductor substrate 10 onto the light reflecting film LR through the diffraction lens DL.

[0075] The light reflection film LR is adapted to reflect light that has passed through the SPAD 2 without undergoing photoelectric conversion and has reached the surface 10C side of the semiconductor substrate 10 in the direction toward the SPAD 2. In the absence of a diffraction lens DL, the light that has reached the surface 10C side of the semiconductor substrate 10 does not necessarily hit the light reflection film LR, and sometimes escapes from the gap of the light reflection film LR to the outside of the pixel P. This results in a reduction in PDE. In addition, light that escapes from a pixel P enters another pixel P, sometimes causing crosstalk to occur.

[0076] As described above, the sensor chip 1 of the present embodiment is provided with a diffraction lens DL. Therefore, the light reaching the surface 10C side of the semiconductor substrate 10 can be converged onto the light reflection film LR. This makes it possible to increase the light reflected by the light reflection film LR and returned to the SPAD 2. By returning the light to the SPAD 2, the chance of the light being photoelectrically converted is increased, which is beneficial to the PDE. This can improve the PDE. In addition, the light is suppressed from escaping to the outside of the pixel P. Therefore, crosstalk can be suppressed.

[0077] In particular, when the first concavo-convex portion 10B is provided on the light incident surface 10A, the light entering the SPAD 2 is diffused by the first concavo-convex portion 10B, so that the optical path length in the SPAD 2 can be increased, thereby improving the PDE. At the same time, on the surface 10C side of the semiconductor substrate 10, the increase in light that does not hit the light reflecting film LR sometimes leads to a decrease in PDE. In the sensor chip 1, in order to improve the PDE, the first concavo-convex portion 10B is provided on the light incident surface 10A. In addition, on the surface 10C side of the semiconductor substrate 10, the light is converged onto the light reflecting film LR to increase the light reflected toward the SPAD 2. This can also improve the PDE.

[0078] As described above, in the sensor chip 1 of the present embodiment, the PDE in the pixel can be improved. In addition, by suppressing the escape of light to the outside of the pixel P, crosstalk can be suppressed.

[0079] <2. Modifications>

[0080] In the following, a modification of the sensor chip 1 according to the above-described embodiment is described. Note that in the following modification, the same configuration as that in the above-described embodiment is given the same reference numeral.

[0081] [Variation A]

[0082] In the above-mentioned sensor chip 1, the second concavo-convex shape portion 10D (diffractive lens DL) has a structure including a laminated body of an insulating film 20 and a conductive film 21. However, the present disclosure is not limited thereto. The second concavo-convex shape portion 10D (diffractive lens DL) may have a structure including an insulating film 27B embedded in a groove 27A provided on the surface (surface 10C of the semiconductor substrate 10) on the side opposite to the light incident surface 10A of the SPAD 2.

[0083] Figure 3 An example of a cross-sectional structure of a pixel P of a sensor chip 1A as a modification A is shown. A groove 27A is provided on the surface of the SPAD 2 on the side opposite to the light incident surface 10A (the surface 10C of the semiconductor substrate 10). An insulating film 27B is embedded in the groove 27A. For example, the insulating film 27B includes silicon oxide. The insulating film 27B includes concave-convex shaped portions that are concentrically and periodically arranged to provide a second concave-convex shaped portion 10D. The second concave-convex shaped portion 10D functions as a diffraction lens DLA. The insulating film 27B embedded in the groove 27A is formed by the same layer as the STI (Shallow Trench Isolation) element separation film that is provided in the area of ​​the semiconductor substrate 10 where the pixel P is not provided. Except for the above description, the sensor chip 1A has the same structure as the sensor chip 1.

[0084] In the pixel P of the sensor chip 1A, as in the sensor chip 1, light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DL, and is reflected by the light reflection film LR toward the SPAD 2. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. In addition, the diffraction lens DL can be implemented without a side wall.

[0085] [Variation Example B]

[0086] In the above-mentioned sensor chip 1, the second concavo-convex shape portion 10D (diffractive lens DL) has a structure including a laminated body of an insulating film 20 and a conductive film 21. However, the present disclosure is not limited thereto. The second concavo-convex shape portion 10D (diffractive lens DL) may have a structure including a conductive film 28 provided on the surface of the SPAD 2 on the side opposite to the light incident surface 10A (the surface 10C of the semiconductor substrate 10).

[0087] Figure 4An example of a cross-sectional structure of a pixel P of a sensor chip 1B as a modified example B is shown. A conductive film 28 is provided on the surface of the SPAD 2 on the side opposite to the light incident surface 10A (the surface 10C of the semiconductor substrate 10) via a sidewall insulating film 22 and a passivation insulating film 23. The sidewall insulating film 22 is the same layer as the sidewall insulating film provided on the side wall of the gate electrode of the transistor in the unillustrated region of the semiconductor substrate 10. For example, the conductive film 28 includes polycrystalline silicon. The conductive film 28 includes concave-convex shaped portions that are concentrically and periodically provided to provide a second concave-convex shaped portion 10D. The second concave-convex shaped portion 10D functions as a diffraction lens DLB. The conductive film 28 is formed by the same layer as the film provided as wiring in the region where the pixel P is not provided. Except for the above description, the sensor chip 1B has the same structure as the sensor chip 1.

[0088] In the pixel P of the sensor chip 1B, as in the sensor chip 1, the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DLB, and is reflected by the light reflection film LR toward the SPAD 2. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. In addition, the diffraction lens DL can be implemented without a side wall.

[0089] The film included in the second concavo-convex portion 10D is not limited to the conductive film 28. When the film included in the second concavo-convex portion 10D includes an insulating film such as silicon oxide or silicon nitride, the same effect as described above can be obtained. In addition, the conductive film 28 or the insulating film included in the second concavo-convex portion 10D may be a multilayer film.

[0090] [Variant C]

[0091] The sensor chip 1 described above has a configuration in which a diffraction lens DL is provided between the SPAD 2 and the light reflection film LR. However, the present disclosure is not limited thereto. A configuration in which an inner lens IL is provided instead of the diffraction lens DL may be provided.

[0092] Figure 5 An example of a cross-sectional configuration of a pixel P of a sensor chip 1C is shown as Modification C. An inner lens IL is provided between the SPAD 2 and the light reflecting film LR. The inner lens IL includes, for example, a material having a refractive index higher than that of silicon oxide. Figure 5 The inner lens IL is shown to have a shape protruding from the light reflecting film LR toward the SPAD 2. However, this is not restrictive. For example, the inner lens IL may also have a shape protruding from the SPAD 2 toward the light reflecting film LR. Except for the above description, the sensor chip 1C has the same configuration as the sensor chip 1.

[0093] In the pixel P of the sensor chip 1C, as in the sensor chip 1, light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged by the inner lens IL onto the light reflection film LR, and is reflected by the light reflection film LR toward the SPAD 2. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed.

[0094] [Variant D]

[0095] In the above-mentioned sensor chip 1, the second concavo-convex shape portion 10D (diffractive lens DL) has a structure of a laminated body including an insulating film 20 and a conductive film 21. However, the present disclosure is not limited thereto. The second concavo-convex shape portion 10D (diffractive lens DL) may include a conductive film in the same layer as any layer of the layers of two or more wirings embedded in the wiring layer 26.

[0096] Figure 6 An example of a cross-sectional configuration of a pixel P of a sensor chip 1D as a modification D is shown. Two or more stacked wirings are embedded in the wiring layer 26. The two or more wirings include, for example, a first wiring 25B, a second wiring 25D, a third wiring 25F, and a fourth wiring 25H. Note that although Figure 6 An example including four layers of stacked wiring is shown, but there is no particular restriction on the number of stacked layers of the wiring. These wirings are connected by a contact layer 25A, a first vertical connection layer 25C, a second vertical connection layer 25E, and a third vertical connection layer 25G. The first wiring 25B, the second wiring 25D, the third wiring 25F, the fourth wiring 25H, the contact layer 25A, the first vertical connection layer 25C, the second vertical connection layer 25E, and the third vertical connection layer 25G, for example, respectively include a metal film of copper or the like. The second concave-convex shape portion 10D is arranged on a conductive film of the same layer as the first wiring 25B to provide a diffraction lens DLC. The first wiring 25B is the layer closest to SPAD 2 in the stacked wiring. In addition, the portion of the second wiring 25D opposite to SPAD 2 constitutes a light reflection film LR. The third wiring 25F is arranged inside the insulating film 24. The fourth wiring 25H is exposed from the insulating film 24 and is used as a terminal for external connection. The sensor chip 1D has the same configuration as the sensor chip 1 except for the above description.

[0097] In the pixel P of the sensor chip 1D, as in the sensor chip 1, the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DLC, and is reflected toward the SPAD 2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. By changing the layout shape of two or more wirings embedded in the wiring layer 26, a structure including the diffraction lens DL and the light reflection film LR can be realized.

[0098] [Variant E]

[0099] The sensor chip 1D has a configuration in which a second concavo-convex portion 10D (diffractive lens DLC) is provided in a layer (first wiring 25B) of the stacked wiring closest to the SPAD 2. However, the present disclosure is not limited thereto. The contact layer 25A may be provided between each first wiring 25B and the SPAD 2 constituting the second concavo-convex portion 10D in a concentric circular shape.

[0100] Figure 7 An example of a cross-sectional configuration of a pixel P of a sensor chip 1E as a modification E is shown. The configuration of two or more stacked wirings embedded in the wiring layer 26 is the same as that of the sensor chip 1D. In the sensor chip 1E, a contact layer 25A is provided between each of the first wirings 25B constituting the second concave-convex shape portion 10D in a concentric circular shape and the SPAD 2.

[0101] The planar structure of the second concavo-convex portion 10D including the first wiring 25B is Figure 2 The planes shown are of identical construction and are arranged concentrically and periodically. Figure 8 FIG. 2 shows an example of a planar configuration of a contact layer 25A of a sensor chip 1E. The contact layer 25A is provided between each of the first wirings 25B and the SPAD 2 constituting the concentric second concavo-convex shape portion 10D. Figure 8 The contact layer 25A is provided in the dot-shaped layout shape shown. The dot-shaped contact layer 25A overlaps with any one of the concentric second concave-convex shape parts 10D. That is, the contact layer 25A is provided in a manner connected to any one of the second concave-convex shape parts 10D. Except for the above description, the sensor chip 1E has the same structure as the sensor chip 1D. Note that the contact layer 25A is not limited to Figure 8 For example, the contact layer 25A may also have a concentric layout shape like the second concavo-convex shape portion 10D. Alternatively, they may have a linear layout shape.

[0102] In the pixel P of the sensor chip 1E, as in the sensor chip 1D, the light that has passed through the SPAD2 and reached the surface 10C side of the semiconductor substrate 10 is converged by the diffraction lens DLC onto the light reflection film LR, and is reflected toward the SPAD2 by the light reflection film LR. Therefore, PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. By changing the layout shape of two or more wirings embedded in the wiring layer, a diffraction lens DL and a light reflection film LR can be provided. The contact layer 25A is arranged to be connected to each concentric first wiring 25B. Therefore, the position of the cathode 16 can be changed within the range that can be connected to the contact layer 25A. This increases the degree of freedom of design. In the case where the cathode 16 is connected to the first wiring 25B that is not the outermost one of the concentric first wirings 25B, the layout shape of the second wiring 25D and the wiring in its upper layer is selected so that it can be connected to the first wiring 25B to which the cathode 16 is connected. In this case, as will be described later in Modification G, the size of the light reflection film LR can be reduced. Thereby, the pixel capacity can be reduced.

[0103] In the sensor chip 1E, the second concavoconvex portion 10D includes a conductive layer in the same layer as the first wiring 25B. However, the second concavoconvex portion 10D may include a conductive film in the same layer as the wiring that is not closest to the SPAD 2 (the second wiring 25D and the wiring in the upper layer thereof).

[0104] [Variant F]

[0105] The sensor chip 1E described above has a configuration in which the cathode 16 is provided at a position closer to the end than the middle of the pixel P. However, the present disclosure is not limited thereto. The cathode 16 may also be provided at the middle of the pixel P in a direction parallel to the light incident surface 10A.

[0106] Fig. 9 An example of a cross-sectional configuration of a pixel P of a sensor chip 1F as a modified example F is shown. The second concavo-convex portion 10D includes a laminate of an insulating film 20 and a conductive film 21. A cathode 16 is provided in the middle portion of the pixel P in a direction parallel to the light incident surface 10A, and a contact layer 25A and a first wiring 25B are provided in a manner connected to the cathode 16. The light reflecting film LR includes a conductive film of the same layer as the second wiring 25D. Except for the above description, the sensor chip 1F has the same configuration as the sensor chip 1E.

[0107] In the pixel P of the sensor chip 1F, as in the sensor chip 1E, light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DL, and is reflected toward the SPAD 2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed.

[0108] [Variant G]

[0109] The above-mentioned sensor chip 1F has a configuration in which the light reflecting film LR is disposed opposite to almost the entire area of ​​the pixel P in a direction parallel to the light incident surface 10A. However, the present disclosure is not limited thereto. The sensor chip 1F may also have a configuration in which the light reflecting film LR is disposed opposite to a portion of the pixel P including a middle portion in a direction parallel to the light incident surface 10A.

[0110] Fig.10 An example of a cross-sectional configuration of a pixel P of a sensor chip 1G as a modification G is shown. The light reflecting film LR includes a conductive layer of the same layer as the second wiring 25D, and is provided to oppose a portion of the pixel P including a middle portion in a direction parallel to the light incident surface 10A. That is, as Fig. 9 As shown, the area extending in the direction parallel to the light incident surface 10A is smaller than the area of ​​the light reflecting film LR having a configuration disposed opposite to almost the entire area of ​​the pixel. Except for the above description, the sensor chip 1G has the same configuration as the sensor chip 1F.

[0111] In the pixel P of the sensor chip 1G, as in the sensor chip 1F, the light that has passed through the SPAD2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DL, and is reflected toward the SPAD2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the light is suppressed from escaping to the outside of the pixel P, so that the crosstalk can be suppressed. By reducing the size of the light reflection film LR, the pixel capacity can be reduced.

[0112] [Variation H]

[0113] In the above-described sensor chip 1G, two or more wirings embedded in the wiring layer 26 are a laminate of four-layer wirings. However, the present disclosure is not limited thereto. Two or more wirings embedded in the wiring layer 26 may include three or fewer layers.

[0114] Fig.11An example of a cross-sectional configuration of a pixel P of a sensor chip 1H as a modification H is shown. Two or more wirings embedded in the wiring layer 26 are a three-layer stack including a first wiring 25B, a second wiring 25D, and a third wiring 25F. These wirings are connected by a contact layer 25A, a first vertical connection layer 25C, and a second vertical connection layer 25E. The light reflection film LR includes a conductive layer of the same layer as the first wiring 25B, and is disposed opposite to a portion of the pixel P including a middle portion in a direction parallel to the light incident surface 10A. Except for the above description, the sensor chip 1H has the same configuration as the sensor chip 1G.

[0115] In the pixel P of the sensor chip 1H, as in the sensor chip 1G, the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged by the diffraction lens DL onto the light reflection film LR, and is reflected toward the SPAD 2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. In addition to reducing the size of the light reflection film LR, the pixel capacity can also be reduced by reducing the number of layers of wiring embedded in the wiring layer 26.

[0116] [Modification Example 1]

[0117] In the above-described sensor chip 1, the first concavo-convex shape portion 10B is provided on the light incident surface 10A of the SPAD 2. However, the present disclosure is not limited thereto. The light incident surface 10A may also be a flat surface.

[0118] Fig.12 An example of a cross-sectional structure of a pixel P of a sensor chip 1I as Modification 1 is shown. The light incident surface 10A of the SPAD 2 is a flat surface. The anti-reflection film 35 covering the light incident surface 10A is also formed flat. Except for the above description, the sensor chip 1I has the same structure as the sensor chip 1.

[0119] In the pixel P of the sensor chip 1I, as in the sensor chip 1, the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DL, and is reflected toward the SPAD 2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. Although light scattering formed by the first concave-convex shape portion 10B does not occur, by returning the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 to the SPAD 2 side, the same effect can be obtained in terms of contribution to sensitivity.

[0120] [Variant J]

[0121] In the above-described sensor chip 1I, the on-chip lens 34 is disposed to be opposed to the light incident surface 10A of the SPAD 2. However, the present disclosure is not limited thereto. A configuration without the on-chip lens 34 may be provided.

[0122] Fig.13 An example of a cross-sectional structure of a pixel P of a sensor chip 1J as a modification J is shown. The light incident surface 10A of the SPAD 2 is a flat surface, and the anti-reflection film 35 provided in a manner covering the light incident surface 10A also has a flat surface. The on-chip lens 34 is not provided on the light incident surface 10A. Except for the above description, the sensor chip 1J has the same structure as the sensor chip 1.

[0123] In the pixel P of the sensor chip 1J, as with the sensor chip 1I, the light that has passed through the SPAD2 and reached the surface 10C side of the semiconductor substrate 10 is converged onto the light reflection film LR by the diffraction lens DL, and is reflected toward the SPAD2 by the light reflection film LR. Therefore, the PDE can be improved. In addition, the escape of light to the outside of the pixel P is suppressed, so that crosstalk can be suppressed. Although light scattering formed by the first concave-convex shape portion 10B does not occur, the same effect can be obtained in terms of contribution to sensitivity by returning the light that has passed through the SPAD 2 and reached the surface 10C side of the semiconductor substrate 10 to the SPAD 2 side. In particular, since the on-chip lens 34 is not provided, the amount of light that passes through the SPAD 2 and reaches the surface 10C side of the semiconductor substrate 10 increases. By converging the light on the light reflection film LR by the diffraction lens DL and reflecting the light toward the SPAD 2 by the light reflection film LR, the effect of improving the PDE can be enhanced.

[0124] <3. Application Examples>

[0125] The above-described sensor chip 1 and sensor chips 1A to 1J (represented by sensor chip 1 ) are suitable for various electronic devices including, for example, cameras such as digital cameras or digital video cameras, mobile phones with a camera function, or any other devices with a camera function.

[0126] Fig.14 : is a block diagram showing an example of a schematic configuration of an electronic device including the sensor chip 1 according to any of the above-described embodiments and their modified examples.

[0127] Fig.14 The electronic device 201 shown includes an optical system 202, a shutter device 203, a sensor chip 1, a drive circuit 205, a signal processing circuit 206, a monitor 207, and a memory 208, and is capable of performing imaging of still images and moving images.

[0128] The optical system 202 includes one or more lenses. The optical system 202 guides light (incident light) from a subject to the sensor chip 1 to form an image on a light receiving surface of the sensor chip 1 .

[0129] The shutter device 203 is provided between the optical system 202 and the sensor chip 1. The shutter device 203 controls the light irradiation period and the light shielding period of the sensor chip 1 according to the control of the drive circuit 205.

[0130] The sensor chip 1 has a package including the above-described sensor chip. The sensor chip 1 generates signal charges based on light formed as an image on a light receiving surface via an optical system 202 and a shutter device 203. The signal charges generated in the sensor chip 1 are supplied to a signal processing circuit 206.

[0131] The signal processing circuit 206 performs various signal processing on the signal charge supplied from the sensor chip 1. An image (image data) obtained as a result of the signal processing performed by the signal processing circuit 206 is supplied to the monitor 207 and displayed, or supplied to the memory 208 and stored (recorded).

[0132] By using the sensor chip 1 , the electronic device 201 constructed as described above can improve the PDE, thereby obtaining a high-definition imaging image.

[0133] <4. Application Examples>

[0134] The technology according to the present disclosure (the present technology) is applicable to various products. For example, the technology according to the present disclosure can be implemented as a device installed on any type of mobile body, such as a car, an electric car, a hybrid car, a motorcycle, a bicycle, a personal mobile device, an airplane, a drone, a ship, or a robot.

[0135] Fig.15 : is a block diagram showing an example of a schematic configuration of a vehicle control system as an example of a moving body control system to which the technology according to the embodiment of the present disclosure can be applied.

[0136] The vehicle control system 12000 includes a plurality of electronic control units connected to each other via a communication network 12001. Fig.15 In 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. In addition, as a functional configuration of the integrated control unit 12050, a microcomputer 12051, a sound / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0137] The drive system control unit 12010 controls the operation of the devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 serves as a control device for the following devices: a drive force generating device such as an internal combustion engine or a drive motor for generating the drive force of the vehicle; a drive force transmitting 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 the braking force of the vehicle.

[0138] 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 serves as a control device for each of the following devices: a keyless entry system; a smart key system; a power window device; or various lights such as a headlight, a taillight, a brake light, a turn signal light, or a fog light. In this case, it is possible to input radio waves or signals of various switches sent from a mobile device that replaces the key to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals and controls the door lock device, the power window device, or the lights of the vehicle.

[0139] The vehicle exterior information detection unit 12030 detects information on the exterior of the vehicle including the vehicle control system 12000. For example, the vehicle exterior information detection unit 12030 is connected to the camera unit 12031. The vehicle exterior information detection unit 12030 causes the camera unit 12031 to capture an image of the exterior of the vehicle and receives the captured image. Based on the received image, the vehicle exterior information detection unit 12030 can perform detection processing on objects such as pedestrians, vehicles, obstacles, signs, or letters on the road surface, or detection processing of the distance thereto.

[0140] The imaging unit 12031 is an optical sensor for receiving light and outputting an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or can output the electrical signal as distance measurement information. In addition, the light received by the imaging unit 12031 may be visible light, or may be non-visible light such as infrared rays.

[0141] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection unit 12041 for detecting the driver's state. For example, the driver state detection unit 12041 includes a camera for photographing 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 can determine whether the driver is dozing off.

[0142] Based on the information outside or inside the vehicle acquired by the outside information detection unit 12030 or the inside information detection unit 12040, the microcomputer 12051 can calculate the control target value of the driving force generating device, the steering mechanism, or the braking device, and can output a control command to the driving system control unit 12010. For example, the microcomputer 12051 can perform cooperative control for realizing the functions of the advanced driver assistance system (ADAS), which includes: collision avoidance or collision mitigation of the vehicle, following driving based on the following distance, speed maintenance driving, vehicle collision warning, or lane departure warning of the vehicle.

[0143] In addition, the microcomputer 12051 is capable of controlling the driving force generating device, steering mechanism, or braking device, etc. based on the information related to the outside or inside of the vehicle obtained by the outside information detection unit 12030 or the inside information detection unit 12040, thereby performing collaborative control for realizing automatic driving that enables the vehicle to drive autonomously without relying on the driver's operation.

[0144] Furthermore, based on the information outside the vehicle acquired by the vehicle exterior information detection unit 12030, the microcomputer 12051 can output a control command to the body system control unit 12020. For example, the microcomputer 12051 can control the headlights and change the high beam to the low beam, for example, according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030, thereby performing cooperative control for preventing glare.

[0145] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device, which can visually or auditorily notify passengers on the vehicle or the outside of the vehicle of information. Fig.15 In the example of FIG. 1 , as output devices, an audio speaker 12061, a display portion 12062, and an instrument panel 12063 are shown. For example, the display portion 12062 may include at least one of an on-board display and a head-up display.

[0146] Fig.16 This is a diagram showing an example of the installation position of the camera unit 12031.

[0147] exist Fig.16 In the figure, the camera unit 12031 includes camera units 12101, 12102, 12103, 12104 and 12105.

[0148] The camera units 12101, 12102, 12103, 12104 and 12105 are, for example, arranged at the front nose, rearview mirror, rear bumper and rear door of the vehicle 12100 and at the upper part of the windshield in the vehicle. The camera unit 12101 arranged at the front nose and the camera unit 12105 arranged at the upper part of the windshield in the vehicle mainly acquire images in front of the vehicle 12100. The camera units 12102 and 12103 arranged at the rearview mirror mainly acquire images from the side of the vehicle 12100. The camera unit 12104 arranged at the rear bumper or rear door mainly acquires images from the rear of the vehicle 12100. The camera unit 12105 arranged at the upper part of the windshield in the vehicle is mainly used to detect the vehicle in front, pedestrians, obstacles, traffic lights, traffic signs or lanes, etc.

[0149] By the way, Fig.16 Examples of the imaging ranges of the imaging units 12101 to 12104 are shown. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided at the front nose. The imaging ranges 12112 and 12113 respectively indicate the imaging ranges of the imaging units 12102 and 12103 provided at the rearview mirror. The imaging range 12114 indicates the imaging range of the imaging unit 12104 provided at the rear bumper or the rear door. For example, by superimposing the image data imaged by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 seen from above is obtained.

[0150] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

[0151] For example, the microcomputer 12051 can determine the distance to each three-dimensional object within the imaging range 12111 to 12114 and the change of the distance over time (relative speed relative to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104, thereby extracting the following three-dimensional object as the leading vehicle: in particular, the three-dimensional object is closest to the vehicle 12100 on the driving road of the vehicle 12100 and is traveling at a predetermined speed (for example, greater than or equal to 0 km / h) in almost the same direction as the vehicle 12100. In addition, the microcomputer 12051 can pre-set the following distance to be maintained in front of the leading vehicle, and can perform automatic braking control (including follow-up stop control) or automatic acceleration control (including follow-up start control) and the like. Therefore, cooperative control for realizing automatic driving and the like that enables the vehicle to travel autonomously without relying on the driver's operation can be performed.

[0152] For example, based on the distance information obtained from the camera units 12101 to 12104, the microcomputer 12051 can classify the three-dimensional object data about the three-dimensional object into three-dimensional object data of two-wheeled vehicles, standard vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that the driver of the vehicle 12100 can visually identify and obstacles that are difficult for the driver of the vehicle 12100 to visually identify. Then, the microcomputer 12051 determines a collision risk for indicating the risk of collision with each obstacle. In the case where the collision risk is equal to or higher than the set value and therefore there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver through the audio speaker 12061 or the display unit 12062, and performs forced deceleration or evasive steering through the drive system control unit 12010. Therefore, the microcomputer 12051 can assist driving to avoid collision.

[0153] At least one of the camera units 12101 to 12104 may be an infrared camera for detecting infrared rays. For example, the microcomputer 12051 is capable of identifying a pedestrian by determining whether the pedestrian exists in the image captured by the camera units 12101 to 12104. For example, such pedestrian recognition is performed by the following process: extracting feature points in the image captured by the camera units 12101 to 12104 as infrared cameras; and determining whether the object is a pedestrian by pattern matching a series of feature points representing the outline of the object. When the microcomputer 12051 determines that a pedestrian exists in the image captured by the camera units 12101 to 12104 and identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 so that a rectangular outline for emphasis is superimposed and displayed on the identified pedestrian. The sound / image output unit 12052 may also control the display unit 12062 so that an icon or the like for representing a pedestrian is displayed at a desired position.

[0154] An example of a mobile body control system to which the technology according to the present disclosure is applicable has been described above. The technology according to the present disclosure is applicable to the camera unit 12031 in the above-mentioned components. Specifically, the sensor chip 1 according to any one of the above-mentioned embodiments and their modified examples is applicable to the camera unit 12031. By applying the technology according to the present disclosure to the camera unit 12031, PDE can be improved, thereby obtaining a high-definition camera image. Therefore, the camera image in the mobile body control system can be used for high-precision control.

[0155] <5. Other Modifications>

[0156] The present disclosure has been described above with reference to the embodiment and its modified examples A to J, applicable examples, and application examples. However, the present disclosure is not limited to the above-described embodiment and the like, and can be modified in various ways.

[0157] The sensor chip of any one of the above-mentioned embodiments and their variations is suitable for a distance measuring device that calculates the distance to a measurement target based on an output signal of the sensor chip. In this case, the distance measuring device includes a signal processing circuit that calculates the distance to a measurement target based on an output signal of the sensor chip.

[0158] In addition, in the sensor chip of any of the above-mentioned embodiments and modifications, a focusing portion such as a diffraction lens or an inner lens may not be provided outside the effective pixel area (for example, an invalid pixel or a pixel peripheral portion where light is blocked by a light shielding film). In the case of providing a pixel array, there is no particular limitation on the number of pixels. In addition, the embodiments and modifications A to J thereof can be appropriately combined.

[0159] In addition, the SPAD 2 of each pixel P of the embodiment and its variants A to J may have a structure in which an n-type impurity region and a p-type impurity region are replaced with each other. In this case, an n-type impurity region is provided between the side of the well layer 11 and the pixel separation film TI, and a cathode is provided at the end of the n-type impurity region. In addition, an n-type impurity region and a p-type impurity region providing a pn junction are provided inside the well layer 11, and an anode is provided in a manner connected to the p-type impurity region. The driving of the SPAD having such a structure is performed by applying a high negative voltage to the anode 13 and thereby applying a predetermined reverse voltage to the pn junction.

[0160] It should be noted that the effects described herein are merely exemplary. The effects of the present disclosure are not limited to the effects described herein. The present disclosure may have effects other than the effects described herein.

[0161] Note that the present technology may have the following configuration. According to the present technology having the following configuration, PDE can be improved. (1)

[0163] A sensor chip, comprising:

[0164] A pixel, the pixel comprising:

[0165] a photoelectric conversion portion including a light incident surface on which light is incident and a multiplication region for avalanche multiplication of carriers by a high electric field region;

[0166] a light reflecting portion provided to face a surface of the photoelectric conversion portion on the opposite side of the light incident surface; and

[0167] The light focusing portion is provided between the photoelectric conversion portion and the light reflecting portion. (2)

[0169] The sensor chip according to the above (1), wherein the light collecting portion collects the light having passed through the photoelectric conversion portion toward the light reflecting portion. (3)

[0171] The sensor chip according to (1) or (2) above, wherein the light incident surface is provided with a first concavo-convex portion for diffusing the light. (4)

[0173] The sensor chip according to any one of (1) to (3) above, further comprising an on-chip lens disposed opposite to the light incident surface. (5)

[0175] The sensor chip according to any one of (1) to (4) above, wherein the light collecting section includes a diffraction lens. (6)

[0177] The sensor chip according to the above (5), wherein the diffractive lens includes second concavo-convex portions that are provided concentrically and periodically. (7)

[0179] The sensor chip according to the above (6), wherein the second concavo-convex portion is formed of a conductive film. (8)

[0181] The sensor chip according to the above (6), wherein the second concavo-convex portion is formed of a laminate of an insulating film and a conductive film. (9)

[0183] The sensor chip according to the above (6), wherein the second concavo-convex portion is formed of an insulating film. (10)

[0185] The sensor chip according to (9) above, wherein the insulating film is embedded in a groove provided on a surface of the photoelectric conversion portion on the opposite side to the light incident surface. (11)

[0187] The sensor chip according to (6) above, wherein:

[0188] A wiring layer including two or more stacked wirings embedded in an insulating film is provided on a surface of the photoelectric conversion portion on the opposite side to the light incident surface, and

[0189] The second concavo-convex shape portion is composed of a conductive film in the same layer as one of the two or more wirings. (12)

[0191] The sensor chip according to the above (11), wherein a contact portion is provided between each of the conductive films constituting the second concavo-convex portions and the photoelectric conversion portion. (13)

[0193] The sensor chip according to (11) or (12) above, wherein the second concavo-convex shape portion is composed of a conductive film in the same layer as a layer closest to the photoelectric conversion portion among the two or more wirings. (14)

[0195] The sensor chip according to (11) or (12) above, wherein the second concavo-convex shape portion is composed of a conductive film in the same layer as a layer other than a layer closest to the photoelectric conversion portion among the two or more wirings. (15)

[0197] The sensor chip according to (6) above, wherein:

[0198] A wiring layer including two or more stacked wirings embedded in an insulating film is provided on a surface of the photoelectric conversion portion on the opposite side to the light incident surface, and

[0199] The two or more wirings are provided so as to be connected to the cathode of the photoelectric conversion portion at a middle portion of the pixel in a direction parallel to the light incident surface. (16)

[0201] The sensor chip according to any one of (1) to (15) above, wherein the light reflecting portion is provided to be opposed to a portion of the pixel including a middle portion of the pixel in a direction parallel to the light incident surface. (17)

[0203] The sensor chip according to any one of (1) to (4) above, wherein the light collecting section includes an inner lens. (18)

[0205] An electronic device comprising:

[0206] Optical system;

[0207] sensor chip; and

[0208] A signal processing circuit, wherein

[0209] The sensor chip includes pixels, and the pixels include:

[0210] a photoelectric conversion portion including a light incident surface on which light is incident and a multiplication region for avalanche multiplication of carriers by a high electric field region;

[0211] a light reflecting portion provided to face a surface of the photoelectric conversion portion on the opposite side of the light incident surface; and

[0212] The light focusing portion is provided between the photoelectric conversion portion and the light reflecting portion. (19)

[0214] A distance measuring device, comprising:

[0215] Optical system;

[0216] sensor chip; and

[0217] A signal processing circuit, wherein the signal processing circuit calculates the distance to the measurement target according to the output signal of the sensor chip, wherein:

[0218] The sensor chip includes pixels, and the pixels include:

[0219] a photoelectric conversion portion including a light incident surface on which light is incident and a multiplication region for avalanche multiplication of carriers by a high electric field region;

[0220] a light reflecting portion provided to face a surface of the photoelectric conversion portion on the opposite side of the light incident surface; and

[0221] The light focusing portion is provided between the photoelectric conversion portion and the light reflecting portion.

[0222] This application claims priority based on Japanese Patent Application No. 2019-050885 filed with the Japan Patent Office on March 19, 2019, the entire contents of which are incorporated herein by reference.

[0223] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A sensor chip, comprising: A pixel, the pixel comprising: a photoelectric conversion portion including a light incident surface on which light is incident and a multiplication region for avalanche multiplication of carriers by a high electric field region; a light reflecting portion provided to face a surface of the photoelectric conversion portion on the opposite side of the light incident surface; and a light-collecting portion disposed between the photoelectric conversion portion and the light-reflecting portion, The light focusing portion includes a diffractive lens, and the diffractive lens includes second concave-convex portions that are concentrically and periodically arranged. wherein the second concavo-convex portion is formed of a conductive film; or The second concavo-convex portion is formed of a laminate of an insulating film and a conductive film; or A wiring layer is provided on the surface on the opposite side of the light incident surface of the photoelectric conversion portion, the wiring layer including two or more stacked wirings embedded in an insulating film, and the second concave-convex portion is composed of a conductive film in the same layer as one of the two or more wirings.

2. The sensor chip according to claim 1, wherein: The light collecting portion collects the light that has passed through the photoelectric conversion portion toward the light reflecting portion.

3. The sensor chip according to claim 1 or 2, wherein: The light incident surface is provided with a first concavo-convex portion for diffusing the light. 4 . The sensor chip according to claim 1 , further comprising an on-chip lens disposed opposite to the light incident surface.

5. The sensor chip according to claim 1, wherein: A contact portion is provided between each of the conductive films constituting the second concavo-convex portion and the photoelectric conversion portion.

6. The sensor chip according to claim 1, wherein: The second concavo-convex shape portion is composed of a conductive film in the same layer as a layer closest to the photoelectric conversion portion among the two or more wirings.

7. The sensor chip according to claim 1, wherein: The second concavo-convex shape portion is composed of a conductive film in the same layer as a layer other than a layer closest to the photoelectric conversion portion among the two or more wirings.

8. The sensor chip according to claim 1, wherein: A wiring layer including two or more wirings stacked and embedded in an insulating film is provided on a surface of the photoelectric conversion portion on the opposite side to the light incident surface, and The two or more wirings are provided so as to be connected to the cathode of the photoelectric conversion portion at a middle portion of the pixel in a direction parallel to the light incident surface.

9. The sensor chip according to claim 1 or 2, wherein: The light reflecting portion is provided to oppose a portion of the pixel including a middle portion of the pixel in a direction parallel to the light incident surface.

10. The sensor chip according to claim 1 or 2, wherein: The light focusing portion includes an inner lens.

11. An electronic device, comprising: Optical system; Sensor chip; and A signal processing circuit, wherein The sensor chip is the sensor chip according to any one of claims 1 to 10.

12. A distance measuring device, comprising: Optical system; Sensor chip; and A signal processing circuit, wherein the signal processing circuit calculates the distance to the measurement target according to the output signal of the sensor chip, wherein: The sensor chip is the sensor chip according to any one of claims 1 to 10.

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