Light detection device and distance measurement system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SONY SEMICON SOLUTIONS CORP
- Filing Date
- 2023-07-13
- Publication Date
- 2026-06-05
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to a light detection device and a distance measurement system, and more particularly to a light detection device and a distance measurement system that are capable of achieving improved performance. [Background technology]
[0002] Conventionally, distance measurement systems have been developed that acquire distance images by arranging multiple SPADs (Single Photon Avalanche Diodes) in an array and calculating the distance to an object using the ToF (Time of Flight) method. For example, conventional distance measurement systems have adopted a two-layer structure in which a pixel layer in which the SPADs are arranged and a circuit layer in which the distance measurement circuit is arranged are stacked.
[0003] Patent Document 1 discloses an imaging device having a layered structure in which a layer having photoelectric conversion elements and a plurality of layers having circuits are stacked. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2020-524943 A Summary of the Invention [Problem to be solved by the invention]
[0005] However, in a photodetector with a two-layer structure as described above, all circuits are mounted on one circuit layer, making it difficult to improve distance measurement performance, power consumption, chip size, etc., and there is a demand for improving these performances. Note that, in the imaging device disclosed in the above-mentioned Patent Document 1, although circuits are arranged in multiple layers, so-called peripheral circuits are not provided, and the layers are not configured to be divided according to function.
[0006] The present disclosure has been made in consideration of such circumstances, and is intended to enable further improvement in performance. [Means for solving the problem]
[0007] An optical detection device of one aspect of the present disclosure comprises a first semiconductor substrate on which photon detection elements that detect photons are arranged in an array, a second semiconductor substrate on which a front-stage circuit that converts an analog signal output by the photon detection element in response to detecting a photon into a digital signal and outputs the digital signal is arranged for each of the photon detection elements, and a third semiconductor substrate on which a distance measurement circuit that measures distance based on the digital signal output from the front-stage circuit is arranged for each of the photon detection elements, and is configured in a layered structure in which at least the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are stacked.
[0008] A ranging system according to one aspect of the present disclosure includes an illumination device that emits illumination light, and a light receiving device that receives reflected light from the illumination light, the light receiving device having a first semiconductor substrate on which photon detection elements that detect photons are arranged in an array, a second semiconductor substrate on which a front-stage circuit that converts an analog signal output by the photon detection element in response to detecting a photon into a digital signal and outputs the digital signal is arranged for each of the photon detection elements, and a third semiconductor substrate on which a ranging circuit that measures distance based on the digital signal output from the front-stage circuit is arranged for each of the photon detection elements, and the light detection device has a layered structure in which at least the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are stacked.
[0009] In one aspect of the present disclosure, photon detection elements that detect photons are arranged in an array on a first semiconductor substrate, a front-stage circuit that converts an analog signal output by the photon detection element in response to detecting a photon into a digital signal and outputs the digital signal is arranged for each photon detection element on a second semiconductor substrate, and a distance measurement circuit that measures distance based on the digital signal output from the front-stage circuit is arranged for each photon detection element on a third semiconductor substrate.The first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are at least stacked to form a stacked structure. [Brief description of the drawings]
[0010] [Figure 1] 1 is a diagram illustrating a configuration example of a first embodiment of a photodetector to which the present technology is applied. [Diagram 2] 2 is a diagram showing an example of a cross-sectional configuration of the photodetector of FIG. 1; [Diagram 3] 1 is a diagram illustrating a configuration example of a second embodiment of a photodetector to which the present technology is applied. [Figure 4] 4 is a diagram showing an example of a cross-sectional configuration of the photodetector of FIG. 3. [Diagram 5] 11 is a diagram illustrating a configuration example of a third embodiment of a photodetector to which the present technology is applied. FIG. [Figure 6] 6 is a diagram showing an example of a cross-sectional configuration of the photodetector of FIG. 5. [Figure 7] 1 is a cross-sectional view showing an example of a connection structure of a connection pad via a Cu-Cu joint. [Figure 8] FIG. 13 is a diagram illustrating a configuration example of a fourth embodiment of a photodetector to which the present technology is applied. [Figure 9] 1 is a block diagram showing an example configuration of a ranging system to which the present technology is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.
[0012] <First Configuration Example of Photodetector> A first embodiment of a photodetector to which the present technology is applied will be described with reference to FIGS. 1 and 2. FIG.
[0013] FIG. 1 is a diagram illustrating the layered structure of the photodetector 11. As shown in FIG.
[0014] As shown in FIG. 1, the photodetector 11 has a three-layer structure in which a first semiconductor substrate 12, a second semiconductor substrate 13, and a third semiconductor substrate 14 are stacked.
[0015] The first semiconductor substrate 12 is a pixel layer having a pixel array 22 in which a plurality of SPADs 21 are arranged in an array. The SPAD 21 is a photon detection element having a pixel structure that utilizes avalanche multiplication to amplify electrons from a single incident photon.
[0016] The second semiconductor substrate 13 is a circuit layer in which a plurality of PFE (Pixel Front-End) circuits 31 are arranged corresponding to the individual SPADs 21 of the first semiconductor substrate 12. The PFE circuit 31 is composed of circuit elements that need to receive a high voltage among the pixel circuits provided for each SPAD 21, and is a front-stage circuit that converts an analog signal output by the SPAD 21 in response to detecting a photon into a digital signal and outputs the digital signal.
[0017] The third semiconductor substrate 14 is a circuit layer in which a plurality of distance measuring circuits 41 are arranged corresponding to the individual SPADs 21 of the first semiconductor substrate 12. The distance measuring circuits 41 are subsequent circuits that measure distance based on a digital signal output from the PFE circuit 31 of the pixel circuits provided for each SPAD 21.
[0018] In the photodetector 11, the SPADs 21 and the PFE circuits 31 are electrically connected to each other via through vias 51, and the PFE circuits 31 and the distance measuring circuits 41 are electrically connected to each other via Cu-Cu joints 52. The through vias 51 are formed by embedding metal that will become wiring in fine holes formed to penetrate the first semiconductor substrate 12 and the second semiconductor substrate 13. The Cu-Cu joints 52 are formed by joining Cu pads formed on the respective bonding surfaces of the first semiconductor substrate 12 and the second semiconductor substrate 13 to each other.
[0019] FIG. 2 is a diagram showing an example of a cross-sectional configuration of the photodetector 11. As shown in FIG.
[0020] 2, the photodetector 11 is configured by stacking a first semiconductor substrate 12 on which the SPAD 21 is provided, a second semiconductor substrate 13 on which the PFE circuit 31 is provided, and a third semiconductor substrate 14 on which the distance measurement circuit 41 is provided. The SPAD 21 and the PFE circuit 31 are connected via a through via 51, and the PFE circuit 31 and the distance measurement circuit 41 are connected via a Cu-Cu joint 52.
[0021] In this way, the photodetector 11 can shorten the cathode wiring from the SPAD 21 to the PFE circuit 31 by configuring the PFE circuit 31, which needs to receive a high voltage, on the second semiconductor substrate 13 for each SPAD 21. This enables the photodetector 11 to reduce the cathode capacitance, which is important for the distance measurement performance (POS, etc.) and power consumption of the SPAD 21.
[0022] For example, in a conventional photodetector with a PFE circuit and a ranging circuit on one circuit layer, when the pixel size of the SPAD is small, it was necessary to centralize the PFE circuit, which requires high voltage, and the ranging circuit, which operates at low voltage, in order to improve area efficiency. This resulted in a wiring layout that extended the cathode wiring from the SPAD to the PFE circuit, making it difficult to reduce the cathode capacitance.
[0023] In contrast, the photodetector 11 is configured such that the PFE circuit 31 and the distance measurement circuit 41 are provided on different circuit layers, allowing the PFE circuit 31 to be arranged for each SPAD 21. This allows a wiring layout that shortens the cathode wiring from the SPAD 21 to the PFE circuit 31 compared to the conventional layout, thereby reducing the cathode capacitance. Note that since the distance measurement circuit 41 is configured to receive digital signals, the effect on the characteristics is negligible even if the wiring from the PFE circuit 31 becomes longer.
[0024] In addition, the photodetector 11 has a configuration in which the PFE circuit 31 and the distance measurement circuit 41 are provided on different circuit layers, allowing a larger number of counter bits to be provided per pixel, improving distance measurement accuracy. Also, compared to a conventional configuration in which the PFE circuit and the distance measurement circuit are provided on a single circuit layer, the photodetector 11 can achieve finer pixels with the same performance.
[0025] <Second Configuration Example of Photodetector> A second embodiment of a photodetector to which the present technology is applied will be described with reference to Fig. 3 and Fig. 4. In the photodetector 11A shown in Fig. 3 and Fig. 4, the same components as those in the photodetector 11 in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0026] FIG. 3 is a diagram illustrating the layered structure of the photodetector 11A.
[0027] As shown in Figure 3, the photodetector 11A has a common configuration with the photodetector 11 in Figure 1 in that it is composed of a three-layer structure stacked with a first semiconductor substrate 12A on which SPADs 21 are arranged in an array, a second semiconductor substrate 13A on which a PFE circuit 31 is arranged for each SPAD 21, and a third semiconductor substrate 14A on which a ranging circuit 41 is arranged for each SPAD 21.
[0028] The photodetector 11A has a different configuration from the photodetector 11 of FIG. 1 in that peripheral circuits 61-1 and 61-2 are arranged in the peripheral region of the second semiconductor substrate 13A, and peripheral circuits 61-3 and 61-4 are arranged in the peripheral region of the third semiconductor substrate 14A.
[0029] That is, the photodetector 11A is configured such that the peripheral circuits 61-1 to 61-4 are distributed over the second semiconductor substrate 13A and the third semiconductor substrate 14A. For example, the peripheral circuits 61-1 and 61-2 arranged on the second semiconductor substrate 13A and the peripheral circuits 61-3 and 61-4 arranged on the third semiconductor substrate 14A are arranged to overlap each other in a plan view of the photodetector 11A. Of course, an arrangement in which they do not overlap may be adopted.
[0030] The peripheral circuits 61-1 and 61-2 include thick-film circuits such as a power on reset circuit (PoR), a voltage regulator circuit (LDO: Low Drop Out), a bias circuit, a temperature circuit, a circuit protector circuit, and a Decap circuit.
[0031] The peripheral circuits 61-3 and 61-4 include thin-film circuits such as a PLL (Phase Locked Loop) circuit, an interface circuit, a distance measurement circuit, and other digital circuits. The peripheral circuits 61-3 and 61-4 may include not only thin-film circuits, but also both thin-film and thick-film circuits.
[0032] FIG. 4 is a diagram showing an image of connections in a configuration in which a PoR circuit is mounted as a peripheral circuit 61-1 provided on the second semiconductor substrate 13A.
[0033] 4, the second semiconductor substrate 13A is provided with peripheral circuits 61-1 and 61-2. The third semiconductor substrate 14A is provided with connection pads 71-1 to 71-4, and is provided with an HV block 72 that operates at a high voltage, an MV block 73 that operates at a medium voltage, and an LV block 74 that operates at a low voltage as the peripheral circuits 61-3 and 61-4.
[0034] The connection pads 71-1 to 71-4 are connected to the peripheral circuit 61-1 via the Cu-Cu joints 52a to 52d, respectively. An XCLR signal is input via the connection pad 71-1, a high voltage VDDH is input via the connection pad 71-2, a medium voltage VDDM is input via the connection pad 71-3, and a low voltage VDDL is input via the connection pad 71-4.
[0035] The HV block 72, the MV block 73, and the LV block 74 are connected to the peripheral circuit 61-1 via Cu-Cu joints 52e to 52g, respectively. An XSHUTDOWN signal is input from the peripheral circuit 61-1 to the HV block 72, an XCLR_MV signal is input from the peripheral circuit 61-1 to the MV block 73, and an XCLR_LV signal is input from the peripheral circuit 61-1 to the LV block 74.
[0036] In the photodetector 11A configured in this manner, the peripheral circuit 61 is distributed between the second semiconductor substrate 13A and the third semiconductor substrate 14A, thereby making it possible to reduce the chip size.
[0037] <Third Configuration Example of the Photodetector> A third embodiment of a photodetector to which the present technology is applied will be described with reference to Fig. 5 to Fig. 7. In the photodetector 11B shown in Fig. 5 to Fig. 7, components common to the photodetector 11 in Fig. 1 and the photodetector 11A in Fig. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0038] FIG. 5 is a diagram illustrating the layered structure of the photodetector 11B.
[0039] As shown in Fig. 5, the photodetector 11B has a three-layer structure in which a first semiconductor substrate 12B on which SPADs 21 are arranged in an array, a second semiconductor substrate 13B on which a PFE circuit 31 is arranged for each SPAD 21, and a third semiconductor substrate 14B on which a distance measurement circuit 41 is arranged for each SPAD 21 are stacked, and has a configuration in common with the photodetector 11 in Fig. 1 and the photodetector 11A in Fig. 3 in that peripheral circuits 61-1 and 61-2 are arranged in the peripheral region of the second semiconductor substrate 13B, and peripheral circuits 61-3 and 61-4 are arranged in the peripheral region of the third semiconductor substrate 14B.
[0040] 1 and the photodetector 11A of FIG. 3 in that a plurality of connection pads 81 are arranged along an edge of the second semiconductor substrate 13B, and a plurality of connection pads 82 are arranged along an edge of the third semiconductor substrate 14B. The plurality of connection pads 81 provided on the second semiconductor substrate 13B and the plurality of connection pads 82 provided on the third semiconductor substrate 14B are arranged so as to overlap each other in a plan view of the photodetector 11B.
[0041] In the photodetector 11B, the multiple connection pads 81 provided on the second semiconductor substrate 13B and the multiple connection pads 82 provided on the third semiconductor substrate 14B that are used in common can be connected to each other via the Cu-Cu joints 52. In the example shown in Fig. 5, a voltage supplied to the peripheral circuit 61-2 via the connection pad 81a and a voltage supplied to the peripheral circuit 61-4 via the connection pad 82a are made common. Therefore, the connection pads 81a and 82a are arranged at positions that overlap each other in a plan view, and the connection pads 81a and 82a are connected to each other via the Cu-Cu joints 52.
[0042] In the photodetector 11B, among the multiple connection pads 81 provided on the second semiconductor substrate 13B, those connected only to the peripheral circuit 61 of the second semiconductor substrate 13B and among the multiple connection pads 82 provided on the second semiconductor substrate 13B, those connected only to the peripheral circuit 61 of the second semiconductor substrate 13B can be arranged at positions that overlap in a planar view. In the example shown in Fig. 5, the connection pad 81b connected only to the peripheral circuit 61-1 and the connection pad 82b connected only to the peripheral circuit 61-3 are arranged at positions that overlap in a planar view.
[0043] Therefore, by arranging the connection pads 81 and the connection pads 82 in this manner, the photodetector 11B can reduce the number of connection pads 81 and the connection pads 82 required, and as a result, the chip size can be reduced. Even if the photodetector 11B has a configuration in which the number of connection pads 81 and the connection pads 82 does not affect the chip size, it is possible to improve characteristics such as reducing impedance.
[0044] FIG. 6 is a diagram showing an image of connections in a configuration in which a PoR circuit is mounted as a peripheral circuit 61-1 provided on a second semiconductor substrate 13B.
[0045] 6, the second semiconductor substrate 13B is provided with connection pads 71-1 and 71-2, and is mounted with peripheral circuits 61-1 and 61-2. The third semiconductor substrate 14B is provided with connection pads 71-3 to 71-6, and is mounted with an HV block 72 that operates at a high voltage, an MV block 73 that operates at a medium voltage, and an LV block 74 that operates at a low voltage, as peripheral circuits 61-3 and 61-4.
[0046] The connection pads 71-1 and 71-2 are directly connected to the peripheral circuit 61-1, and the connection pads 71-3 to 71-6 are connected to the peripheral circuit 61-1 via the Cu-Cu joints 52a to 52c, respectively. An XCLR signal is input via the connection pad 71-1, a high voltage VDDH is input via the connection pads 71-2 and 71-3, a medium voltage VDDM is input via the connection pad 71-4, a low voltage VDDL is input via the connection pad 71-5, and a Test signal is input via the connection pad 71-6.
[0047] The HV block 72, MV block 73, and LV block 74 are connected to the peripheral circuit 61-1 via the Cu-Cu joints 52d to 52f, respectively. An XSHUTDOWN signal is input from the peripheral circuit 61-1 to the HV block 72, an XCLR_MV signal is input from the peripheral circuit 61-1 to the MV block 73, and an XCLR_LV signal is input from the peripheral circuit 61-1 to the LV block 74. Furthermore, in the photodetector 11B, a Test signal is input to the LV block 74 via the connection pad 71-6.
[0048] In the photodetector 11B, a connection pad 71-2 and a connection pad 71-3 used for inputting a high voltage VDDH are connected via a Cu-Cu joint 52a.
[0049] In the photodetector 11B, a connection pad 71-1 used for inputting a signal XCLR supplied only to the peripheral circuit 61-1 is provided on the second semiconductor substrate 13B, and a connection pad 71-6 used for inputting a Test signal supplied only to the LV block 74 is provided on the third semiconductor substrate 14B. Therefore, the connection pad 71-1 and the connection pad 71-6 can be arranged at a position where they overlap when the photodetector 11A is viewed from above, similar to the connection pad 81b and the connection pad 82b described with reference to FIG. 5. The connection pad 71-6 used for inputting a Test signal is only used for inspecting the LV block 74 before the second semiconductor substrate 13B is stacked on the third semiconductor substrate 14B, and is not used after the second semiconductor substrate 13B is stacked on the third semiconductor substrate 14B.
[0050] In addition, a connection pad 81 that supplies signals, power, GND, etc. used only on the second semiconductor substrate 13B and a connection pad 82 that supplies signals, power, GND, etc. used only on the third semiconductor substrate 14B can be arranged in a position where they overlap when viewed in a plane with the photodetector 11A.
[0051] FIG. 7 is a diagram illustrating a connection structure of a connection pad 81a and a connection pad 82a connected via a Cu-Cu joint 52. As shown in FIG.
[0052] 7, in the light-detecting device 11B, an opening for wire-bonding wiring from outside to the connection pad 81a is provided so as to penetrate the first semiconductor substrate 12B and reach the connection pad 81a. The connection pad 81a and the Cu-Cu bond 52 are connected via a through electrode 91, and the connection pad 82a and the Cu-Cu bond 52 are connected via a through electrode 92.
[0053] <Fourth Configuration Example of the Photodetector> A fourth embodiment of a photodetector to which the present technology is applied will be described with reference to Fig. 8. In a photodetector 11C shown in Fig. 8, components common to the photodetector 11 in Fig. 1 and the photodetector 11A in Fig. 3 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.
[0054] 8, the photodetector 11C has a three-layer structure in which a first semiconductor substrate 12C on which SPADs 21 are arranged in an array, a second semiconductor substrate 13C on which a PFE circuit 31 is arranged for each SPAD 21, and a third semiconductor substrate 14C on which a distance measurement circuit 41 is arranged for each SPAD 21 are stacked, and has a configuration in common with the photodetector 11 in Fig. 1 and the photodetector 11A in Fig. 3 in that peripheral circuits 61-1 and 61-2 are arranged in the peripheral region of the second semiconductor substrate 13C, and peripheral circuits 61-3 and 61-4 are arranged in the peripheral region of the third semiconductor substrate 14C.
[0055] 1 and the photodetector 11A in Fig. 3 in that an ESD (Electro-Static Discharge) protection element 62 is disposed in the peripheral region of the first semiconductor substrate 12C. For example, the ESD protection element 62 is disposed in a vacant region of the first semiconductor substrate 12C so as to overlap with the peripheral circuits 61-1 to 61-4 when the photodetector 11C is viewed in plan.
[0056] The ESD protection element 62 can be configured by a dummy pixel provided with a surge current path (current path) for passing an ESD surge current in order to protect the SPAD 21 from ESD. In particular, the surge current path of the ESD protection element 62 is configured to be able to pass an amount of current required to protect the SPAD 21 from an ESD surge voltage in the reverse direction of the SPAD 21.
[0057] The photodetector 11C thus configured can protect the SPAD 21 from ESD by providing the ESD protection element 62.
[0058] Furthermore, the photodetector 11C has the ESD protection element 62 disposed in the peripheral region of the first semiconductor substrate 12C, which allows for a smaller chip size than, for example, a configuration in which the ESD protection element 62 is disposed on the second semiconductor substrate 13C or the third semiconductor substrate 14C. In other words, the photodetector 11C can effectively utilize the empty region other than the pixel array 22 on the first semiconductor substrate 12C.
[0059] In this embodiment, the photodetector 11 has been described as having a three-layer structure; however, it is sufficient that the photodetector 11 has a layered structure in which at least the first semiconductor substrate 12, the second semiconductor substrate 13, and the third semiconductor substrate 14 are stacked, and the present technology may be applied to a photodetector 11 having a layered structure of three or more layers.
[0060] <Example of distance measurement system configuration> FIG. 9 is a block diagram showing an example configuration of a distance measuring system to which the present technology is applied.
[0061] As shown in FIG. 9, the distance measurement system 101 is configured to include an illumination device 102 that irradiates laser light toward an object to be measured, a light receiving device 103 that receives the reflected laser light reflected by the object to be measured, and a control device 104 that controls the illumination device 102 and the light receiving device 103.
[0062] The illumination device 102 has a laser driving unit 111, a laser light source 112, and a diffusing lens 113. The laser driving unit 111 drives the laser light source 112 under the control of the control device 104, whereby a pulsed irradiation laser light is emitted from the laser light source 112, and the pulsed irradiation laser light is diffused by the diffusing lens 113 and irradiated toward the object to be measured.
[0063] The light receiving device 103 has a condenser lens 121, an optical sensor 122, and a signal processing unit 123. The pulsed reflected laser light reflected by the object to be measured is condensed by the condenser lens 121 onto the light receiving surface of the optical sensor 122. The optical sensor 122 receives the pulsed reflected laser light in pixel units and outputs an output signal. The output signal is subjected to signal processing in the signal processing unit 123 and then supplied to the control device 104.
[0064] The control device 104 controls the laser driving unit 111 to control the timing at which the pulsed irradiated laser light is emitted, and measures the time it takes for the pulsed reflected laser light to be detected by the optical sensor 122, thereby measuring the distance to the object to be measured.
[0065] In the distance measuring system 101, by applying the light detection device 11 according to each of the above-mentioned embodiments to the light sensor 122, for example, it is possible to further improve the distance measuring performance.
[0066] <Examples of configuration combinations> The present technology can also be configured as follows. (1) a first semiconductor substrate having photon detection elements arranged in an array for detecting photons; a first stage circuit for converting an analog signal output by the photon detection element in response to the detection of a photon into a digital signal and outputting the digital signal is disposed on a second semiconductor substrate for each of the photon detection elements; a distance measuring circuit for measuring a distance based on a digital signal output from the front-stage circuit, the distance measuring circuit including: a third semiconductor substrate disposed for each of the photon detection elements; Equipped with The first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are at least stacked to form a laminate structure. Light detection device. (2) The preceding circuit is a circuit that needs to receive a high voltage. The optical detection device according to (1) above. (3) The photon detection element and the front-stage circuit are connected via a through via, The front-stage circuit and the distance measurement circuit are connected via a Cu-Cu joint. The optical detection device according to (1) or (2) above. (4) a first peripheral circuit is disposed in a peripheral region of a region in which the previous stage circuit is disposed on the second semiconductor substrate; A second peripheral circuit is disposed on the third semiconductor substrate in a peripheral region of the region in which the distance measuring circuit is disposed. The photodetector according to any one of (1) to (3) above. (5) The region in which the first peripheral circuit is arranged and the region in which the second peripheral circuit is arranged are arranged so as to overlap each other in a plan view. The optical detection device according to (4) above. (6) The region in which the first peripheral circuit is arranged and the region in which the second peripheral circuit is arranged are arranged without overlapping each other in a plan view. The optical detection device according to (4) above. (7) a thick-film circuit is mounted as the first peripheral circuit; The second peripheral circuit is provided with only a thin-film circuit or with both a thin-film circuit and a thick-film circuit. The photodetector according to (4) above. (8) a plurality of first connection pads disposed along an edge of the second semiconductor substrate; A plurality of second connection pads are disposed along an edge of the third semiconductor substrate. An optical detection device according to any one of (1) to (7) above. (9) Among the plurality of first connection pads and the plurality of second connection pads, those that are used in common are connected to each other via a Cu-Cu joint. The optical detection device according to (8) above. (10) Among the plurality of first connection pads, those connected only to a first peripheral circuit provided on the second semiconductor substrate and among the plurality of second connection pads, those connected only to a second peripheral circuit provided on the third semiconductor substrate are arranged at positions that overlap each other in a plan view. The optical detection device according to (8) or (9) above. (11) In the first semiconductor substrate, an ESD protection element for protecting the photon detection elements from ESD (Electro-Static Discharge) is arranged in a vacant area other than the area in which the photon detection elements are arranged in an array. An optical detection device according to any one of (1) to (10) above. (12) An illumination device that emits irradiation light; a light receiving device that receives reflected light of the irradiated light; Equipped with The light receiving device is a first semiconductor substrate having photon detection elements arranged in an array for detecting photons; a first stage circuit for converting an analog signal output by the photon detection element in response to the detection of a photon into a digital signal and outputting the digital signal is disposed on a second semiconductor substrate for each of the photon detection elements; a distance measuring circuit for measuring a distance based on a digital signal output from the front-stage circuit, the distance measuring circuit including: a third semiconductor substrate disposed for each of the photon detection elements; having A photodetector having a laminated structure in which at least the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are laminated. have Ranging system.
[0067] In addition, the present embodiment is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present disclosure. In addition, the effects described in this specification are merely examples and are not limiting, and other effects may be obtained. [Explanation of symbols]
[0068] 11 photodetector, 12 first semiconductor substrate, 13 second semiconductor substrate, 14 third semiconductor substrate, 21 SPAD, 22 pixel array, 31 PFE circuit, 41 distance measurement circuit, 51 through via, 52 Cu-Cu junction, 61 peripheral circuit, 62 ESD protection element, 71 connection pad, 72 HV block, 73 MV block, 74 LV block, 81 and 82 connection pad, 91 and 92 through electrode, 101 distance measurement system, 102 lighting device, 103 light receiving device, 104 control device, 111 laser driver, 112 laser light source, 113 diffusing lens, 121 condensing lens, 122 optical sensor, 123 signal processing unit
Claims
1. a first semiconductor substrate having photon detection elements arranged in an array for detecting photons; a first stage circuit for converting an analog signal output by the photon detection element in response to the detection of a photon into a digital signal and outputting the digital signal is disposed on a second semiconductor substrate for each of the photon detection elements; a distance measuring circuit for measuring a distance based on a digital signal output from the front-stage circuit, the distance measuring circuit being disposed for each of the photon detection elements on a third semiconductor substrate; Equipped with The first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are at least stacked to form a laminate structure. Light detection device.
2. The preceding circuit is a circuit that needs to receive a high voltage.
2. The optical detection device according to claim 1.
3. The photon detection element and the front-stage circuit are connected via a through via, The front-stage circuit and the distance measurement circuit are connected via a Cu-Cu joint.
2. The optical detection device according to claim 1.
4. a first peripheral circuit is disposed on the second semiconductor substrate in a peripheral region of a region in which the previous stage circuit is disposed; A second peripheral circuit is disposed on the third semiconductor substrate in a peripheral region of the region in which the distance measuring circuit is disposed.
3. The optical detection device according to claim 2.
5. The region in which the first peripheral circuit is arranged and the region in which the second peripheral circuit is arranged are arranged so as to overlap each other in a plan view.
5. The optical detection device according to claim 4.
6. The region in which the first peripheral circuit is arranged and the region in which the second peripheral circuit is arranged are arranged without overlapping each other in a plan view.
5. The optical detection device according to claim 4.
7. a thick-film circuit is mounted as the first peripheral circuit; As the second peripheral circuit, only a thin-film circuit or both a thin-film circuit and a thick-film circuit are mounted.
5. The optical detection device according to claim 4.
8. a plurality of first connection pads disposed along an edge of the second semiconductor substrate; A plurality of second connection pads are disposed along an edge of the third semiconductor substrate.
2. The optical detection device according to claim 1.
9. Among the plurality of first connection pads and the plurality of second connection pads, those that are used in common are connected to each other via a Cu-Cu joint.
9. The optical detection device according to claim 8.
10. Among the plurality of first connection pads, those connected only to a first peripheral circuit provided on the second semiconductor substrate and among the plurality of second connection pads, those connected only to a second peripheral circuit provided on the third semiconductor substrate are arranged at positions that overlap each other in a plan view.
9. The optical detection device according to claim 8.
11. In the first semiconductor substrate, an ESD protection element for protecting the photon detection elements from ESD (Electro-Static Discharge) is arranged in a vacant area other than the area in which the photon detection elements are arranged in an array.
5. The optical detection device according to claim 4.
12. An illumination device that emits irradiation light; a light receiving device that receives reflected light of the irradiated light; Equipped with The light receiving device is a first semiconductor substrate having photon detection elements arranged in an array for detecting photons; a first stage circuit for converting an analog signal output by the photon detection element in response to the detection of a photon into a digital signal and outputting the digital signal is disposed on a second semiconductor substrate for each of the photon detection elements; a distance measuring circuit for measuring a distance based on a digital signal output from the front-stage circuit, the distance measuring circuit being disposed for each of the photon detection elements on a third semiconductor substrate; having A photodetector having a laminated structure in which at least the first semiconductor substrate, the second semiconductor substrate, and the third semiconductor substrate are laminated. have Ranging system.