Imaging element and imaging device

Abstract

This imaging element comprises: a first substrate that has a first photoelectric conversion unit which converts light into electric charge and which is formed of a first inorganic semiconductor material; and a second substrate that is laminated together with the first substrate and has a second photoelectric conversion unit which is formed of a second inorganic semiconductor material different from the first inorganic semiconductor material and which converts, into electric charge, light that has passed through the first photoelectric conversion unit.

Description

Image sensor and imaging device

[0001] The present invention relates to an image sensor and an imaging device. This application claims priority based on Japanese Patent Application No. 2024-231750, filed on December 27, 2024, the contents of which are incorporated herein by reference.

[0002] Infrared sensors are known (see Patent Document 1). It is required that they output a visible light signal along with an infrared signal.

[0003] Japanese Patent Publication No. 2015-103735

[0004] An image sensor according to one aspect of the invention comprises a first substrate having a first photoelectric conversion unit made of a first inorganic semiconductor material, which converts light into electric charge, and a second substrate laminated together with the first substrate, which has a second photoelectric conversion unit made of a second inorganic semiconductor material different from the first inorganic semiconductor material, which converts light transmitted through the first photoelectric conversion unit into electric charge.

[0005] Figure 1 is a block diagram showing an example of the configuration of an imaging device according to one embodiment of the present invention. Figure 2 is a partially schematic diagram showing a two-layer image sensor according to one embodiment. Figure 3 is a partially cross-sectional view of the image sensor in Figure 2. Figure 3 is a circuit diagram corresponding to a part of the unit group in Figure 2. Figure 5 is a partially schematic cross-sectional view showing an example of the positional relationship between the first and second photoelectric conversion units and the first and second readout units. Figure 6 is a partially schematic diagram showing a three-layer image sensor according to one embodiment. Figure 7 is a partially cross-sectional view of the image sensor in Figure 6. Figure 8 is a circuit diagram corresponding to a part of the unit group in Figure 6. Figure 9 is a schematic diagram showing an example of stacking the first layer BSI readout circuit and the second layer ROIC in Figure 5. Figure 10 is a partially schematic diagram showing a modified example of the image sensor in Figure 6.

[0006] Embodiments of the present invention will be described in detail with reference to the drawings. Figure 1 is a block diagram showing an example of the configuration of an imaging device according to one embodiment of the present invention. The camera (imaging device) 100 comprises an imaging optical system consisting of a photographic lens 120 and a camera body 110. The photographic lens 120 is mounted on the camera body 110. The camera 100 may be configured with the camera body 110 and the photographic lens 120 as an integrated unit. The photographic lens 120 guides the subject light beam incident along the optical axis to the image sensor 200A. The camera body 110 comprises an image sensor 200A, a control unit 101, an image generation unit 102, a recording unit 104, and a display unit 105.

[0007] The photographic lens 120 is composed of multiple optical lenses and forms an image of the subject light beam from the scene onto the light-receiving surface of the image sensor 200A. In Figure 1, a single virtual lens is used to represent the photographic lens 120.

[0008] The control unit 101 includes a CPU and peripheral components such as memory. The control unit 101 controls the operation of the camera 100, including driving the image sensor 200A, reading signals from the image sensor 200A, controlling the image generation unit 102, adjusting the focus of the shooting lens 120, and displaying and recording image data. Some or all of the control functions for driving the image sensor 200A and reading signals from the image sensor 200A may be mounted on the image sensor 200A. The control unit 101 also communicates with the shooting lens 120 to receive lens information and transmit camera information (such as defocus amount and aperture value).

[0009] The image generation unit 102 is an image processing engine that applies various image processing to the signal input from the image sensor 200A. The image generation unit 102 generates first image data based on the signal read from the read circuit 215 (described later) and second image data based on the signal read from the read circuit 216 (described later). The image generation unit 102 applies various image processing to the signal input from the image sensor 200A and generates data for displaying a live view image on the display unit 105 (live view image data) and image data to be stored on a storage medium such as a memory card (still image data). The generated live view image is displayed on the display unit 105 under the control of the control unit 101. The generated still image data is stored on a storage medium by the recording unit 104 under the control of the control unit 101.

[0010] The recording unit 104 has a card slot into which a storage medium such as a memory card can be inserted. The recording unit 104 stores image data and various data generated by the image generation unit 102 on the recording medium inserted in the card slot. The recording unit 104 also has internal memory. In this case, the recording unit 104 can also record image data and various data generated by the image generation unit 102 into its internal memory. The display unit 105 is, for example, a liquid crystal monitor (also called a rear monitor) mounted on the back of the camera body 110.

[0011] Figure 2 is a partially schematic diagram showing a stacked structure (two-layer structure) image sensor according to the first embodiment, and Figure 3 is a partially cross-sectional view of the image sensor in Figure 2. In Figure 3, incident light is mainly indicated by white arrows and is incident toward the image sensor 200A along the Z direction (Z axis direction). Also, as shown in the coordinate axes, the direction to the left of the paper perpendicular to the Z axis is the X direction (X axis direction), and the direction toward the front of the paper perpendicular to the Z axis and X axis is the Y direction (Y axis direction). In some of the following figures, the coordinate axes are displayed with reference to the coordinate axes in Figure 3 so that the orientation of each figure can be seen.

[0012] The image sensor 200A includes a microlens 211, a color filter 212, a visible light sensor 210, and an infrared light sensor 220. The infrared light sensor 220 is positioned on the opposite side of the visible light sensor 210 from the light incident side. The visible light sensor 210 receives light in the visible light band, and the infrared light sensor 220 receives light in the infrared light band and / or the short-wavelength infrared light band (light with a wavelength longer than the wavelength of visible light). The visible light band of the light received by the visible light sensor 210 is, for example, 360 nm to 760 nm. The infrared light band and / or short-wavelength infrared light band of the light received by the infrared light sensor 220 is, for example, 750 nm to 3000 nm.

[0013] The visible light sensor 210 has a substrate (first substrate) 214 on which a photoelectric conversion unit 213A (described later) is provided, and a wiring layer 217. The substrate 214 is, for example, a semiconductor substrate. The visible light sensor 210 may also have a passivation film (not shown) that protects the substrate 214 and functions as a planarization film.

[0014] The microlenses 211 and color filters 212 can also be provided stacked (bonded) to the visible light sensor 210. The microlenses 211 are provided for each photoelectric conversion unit 213A provided on the substrate 214 and focus the incident light on the photoelectric conversion unit 213A. The color filters 212 have color filters 212(B), 212(Gb), 212(Gr), and 212(R). The color filters 212(B), 212(Gr, Gb), and 212(R) are provided for each photoelectric conversion unit 213A and each transmits light in a predetermined wavelength range. The color filters 212(B), 212(Gr, Gb), and 212(R) are arranged in a so-called Bayer array (see Figure 2). Note that the microlenses 211 may be provided for each of the multiple photoelectric conversion units 213A, for example, one microlens 211 may be provided for each of the four photoelectric conversion units. The color filter 212 may be provided for each of the multiple photoelectric conversion units 213A, for example, one color filter 212(B) may be provided for each of the four photoelectric conversion units.

[0015] The photoelectric conversion unit 213A is provided on the substrate 214 and receives light that has passed through the microlens 211 and the color filter 212. The photoelectric conversion unit 213A is, for example, a photodiode that generates an electric charge by photoelectric conversion of incident light. Multiple photoelectric conversion units 213A are provided in the X direction (row direction) and the Y direction (column direction). For example, the photoelectric conversion units 213A are arranged two-dimensionally in the X-Y plane. The substrate 214 has a readout circuit 215 (first readout unit) for reading out a signal based on the electric charge photoelectrically converted by the photoelectric conversion unit 213A, and a readout circuit 216 (second readout unit) for reading out a signal based on the electric charge photoelectrically converted by the photoelectric conversion unit 221A, which will be described later. The wiring layer 217 has wiring 217A for reading signals based on charge photoelectrically converted by the photoelectric conversion unit 213A, and wiring 217B for reading signals based on charge photoelectrically converted by the photoelectric conversion unit 221A of the infrared light sensor 220. Wiring 217A has a plurality of control lines 217Aa for controlling the readout circuit 215 (also called the readout circuit for the BSI type image sensor) (a plurality of control lines 217Aa1, 217Aa2, 217Aa3, 217Aa4 (see Figure 4) for controlling the transfer unit TX1, transfer unit TX2, reset unit RST, selection unit SEL, etc., described later), and a signal line 217Ab for outputting signals via the readout circuit 215 (see Figure 4). The BSI type image sensor is a so-called back-illuminated image sensor. The wiring layer 217 also has output lines for outputting signals read via the read circuit 215 and signal line 217Ab to the outside, although these are not shown. The wiring 217B has multiple control lines 217Ba (reset unit RST2 and selection unit SEL, which will be described later) for controlling the read circuit (ROIC) 216. ＩＲThe ROIC has a plurality of control lines 217Ba1, 217Ba2 (see Figure 4) for controlling each of these, and a signal line 217Bb for outputting a signal via the readout circuit 216 (see Figure 4). The ROIC is a readout integrated circuit. The wiring layer 217, although not shown, has an output line for outputting the signal read out via the readout circuit 216 and the signal line 217Bb to the outside. Note that wiring 217B may be provided on a separate wiring layer from wiring 217A, and wirings 217A and 217B may be composed of multilayer wiring. Signal lines 217Ab and signal lines 217Bb may be provided as different signal lines, or they may be provided as a common signal line. Furthermore, the wiring layer 217 has an opening S1 so that light transmitted through the photoelectric conversion unit 213A is incident on the infrared light sensor 220. The wiring layer 217 is provided between the substrate 214 and the infrared light sensor 220 in the optical axis direction LD of the microlens 211.

[0016] The infrared light sensor 220 has a light-receiving layer 221 and a wiring layer 222. The light-receiving layer 221 has a photoelectric conversion unit 221A that receives light transmitted through the color filters 212(B) and 212(Gr) and the photoelectric conversion unit 213A. The light-receiving layer 221 also has other photoelectric conversion units 221A that receive light from the color filters 212(Gb) and 212(R). The photoelectric conversion unit 221A is, for example, a photodiode that converts incident light photoelectrically to generate an electric charge. The photoelectric conversion unit 221A photoelectrically converts light transmitted through a plurality of photoelectric conversion units 213A provided in the X and Y directions. The light-receiving layer 221 is provided on a substrate 230 (second substrate) and is made of, for example, InGaAs. The light-receiving layer 221 is provided between the wiring layer 222 and the substrate 230 in the optical axis LD of the microlens 211. The substrate 230 also serves as a support substrate for the light-receiving layer 221. The wiring layer 222 has wiring 222A for outputting the charge photoelectrically converted by the photoelectric conversion unit 221A to the readout circuit 216. Wiring 222A is connected to wiring 217B in the wiring layer 217 of the visible light sensor 210. The readout circuit 216, like the readout circuit 215, is provided between the color filter 212 and the wiring layer 217 in the optical axis LD of the microlens 211. The wiring layer 222 also has an opening S2 so that light transmitted through the opening S1 of the visible light sensor 210 is incident on the photoelectric conversion unit 221A. The wiring layer 222 is provided between the wiring layer 217 and the light-receiving layer 221 in the optical axis LD of the microlens 211. In this embodiment, the light-receiving area of ​​the photoelectric conversion unit 221A is larger than the light-receiving area of ​​the photoelectric conversion unit 213A. The visible light sensor 210 is configured such that light transmitted through two pixels is incident on one pixel of the infrared light sensor 220. Alternatively, the visible light sensor 210 may be configured such that light transmitted through one or three or more pixels is incident on one pixel of the infrared light sensor 220. In this embodiment, the LD in the optical axis direction of the microlens is arranged in the order of color filter 212, substrate 214, wiring layer 217, wiring layer 222, light receiving layer 221, and substrate 230, but layers such as planarization films or oxide films may be provided between each of these.

[0017] Figure 4 is a circuit diagram showing the readout circuits 215 and 216 in Figure 2. As an example, Figure 4 describes a circuit that includes two photoelectric conversion units 213Aa and 213Ab, corresponding to the right-hand color filters 212(B) and 212(Gr) in the readout circuits 215 and 216 in Figure 2, and a photoelectric conversion unit 221A located below them. In Figure 4, the symbol Vdd indicates the power supply voltage.

[0018] The image sensor 200A includes a pixel section 20x. The pixel section 20x has a plurality of photoelectric conversion units 213A as photoelectric conversion units for the visible light band, a photoelectric conversion unit 221A as a photoelectric conversion unit for the infrared light band, a readout circuit 215 as a BSI type image sensor, and a readout circuit 216 as a ROIC. The pixel section 20x includes photoelectric conversion units 213Aa and 213Ab as photoelectric conversion units for the visible light band. The pixel section 20x includes the above-mentioned readout circuit 215, which includes a transfer unit TX1, a transfer unit TX2, a reset unit RST, an amplification unit SF, a selection unit SEL (output unit), and an FD area (floating diffusion, storage unit). Here, the photoelectric conversion unit 213Aa is, for example, a photodiode that receives light transmitted through the color filter 212(B) and generates an electric charge, and the photoelectric conversion unit 213Ab is a photodiode that receives light transmitted through the color filter 212(Gr) and generates an electric charge. The transfer unit TX1, the transfer unit TX2, the reset unit RST, the amplification unit SF, and the selection unit SEL are each composed of, for example, transistors. Note that the readout circuit 215 does not necessarily have a selection unit SEL. The photoelectric conversion units 213Aa and 213Ab share a part of the readout circuit 215, and as shown by the dashed line in Figure 4, circuit 215Aa is a readout circuit for reading a signal based on the electric charge photoelectrically converted by the photoelectric conversion unit 213Aa, and circuit 215Ab is a readout circuit for reading a signal based on the electric charge photoelectrically converted by the photoelectric conversion unit 213Ab. Circuits 215Aa and 215Ab share the reset section RST, the amplification section SF, the selection section SEL, and the FD area. Furthermore, the pixel section 20x includes a photoelectric conversion section 221A as a photoelectric conversion section in the infrared light band. The pixel section 20x, as the readout circuit 216 described above, includes an amplifier OP, a capacitor C, a reset section RST2, and a selection section SEL. ＩＲ It is equipped with the following. The reading circuit 216 is a selection unit SELＩＲ It is not necessary to have it.

[0019] Transfer unit TX1 transfers the charge generated by the photoelectric conversion unit 213Aa to the FD region. Transfer unit TX2 transfers the charge generated by the photoelectric conversion unit 213Ab to the FD region. In the following description, when transfer unit TX1 and transfer unit TX2 are not distinguished, they will be collectively referred to as transfer unit TX. Transfer unit TX turns on and transfers charge when the control signal φTx reaches a High level, and turns off when the control signal φTx reaches a Low level.

[0020] The FD region converts the transferred charge into a voltage. The amplification unit SF forms a source follower circuit and outputs a signal based on the charge accumulated in the FD region. The reset unit RST discharges the charge from the FD region and the photoelectric conversion units 213Aa and 213Ab to reset them to the reference potential. The reset unit RST turns on when the control signal φRST reaches a high level and turns off when the control signal φRST reaches a low level. The selection unit SEL outputs the signal output from the amplification unit SF to the signal line 217Ab.

[0021] The photoelectric conversion unit 221A is positioned below the photoelectric conversion units 213Aa and 213Ab in the optical axis direction LD (see Figure 3). The apertures S1 and S2 (see Figure 3) are provided, for example, below the photoelectric conversion units 213Aa and 213Ab. The wiring layer 217 photoelectric conversion unit 221A outputs a signal based on the charge generated by photoelectric conversion of infrared light incident through the apertures S1 and S2 to the amplifier OP. The amplifier OP and capacitor C amplify the signal based on the charge photoelectrically converted by the photoelectric conversion unit 221A and output to the selection unit SEL ＩＲ Output to: SEL selection section ＩＲ The signal output from amplifier OP is output to signal line 217Ab. The reset unit RST2 discharges the charge from capacitor C and resets it to the reference potential.

[0022] Furthermore, the image sensor 200A has an A / D conversion circuit (signal processing unit) 23 connected to the signal line 217Ab. The A / D conversion circuit 23 converts the analog signals output from the readout circuit 215 and / or the readout circuit 216 into digital signals. The A / D conversion circuit 23 is provided on the substrate 214. The image sensor 200A does not necessarily have an A / D conversion circuit 23. In that case, the analog signals output from the readout circuit 215 and / or the readout circuit 216 are output to the outside of the image sensor 200A via the signal line 217Ab and converted into digital signals by an A / D conversion circuit (signal processing unit) (not shown) provided outside the image sensor 200A. Alternatively, the analog signal output from the readout circuit 215 may be converted into a digital signal by the A / D conversion circuit 23, and the analog signal output from the readout circuit 216 may be output directly to the outside of the image sensor 200A.

[0023] Figure 5 is a partially schematic cross-sectional view showing an example of the positional relationship between the photoelectric conversion units 213A, 221A and the readout circuits 215, 216. In Figure 5, as an example, a plurality of photoelectric conversion units 213A located in the upper layer and one photoelectric conversion unit 221A located in the lower layer will be used for explanation. As shown in Figure 5, with reference to the side from which light is incident, in the first layer of the visible light sensor 210, the photoelectric conversion units 213A are arranged evenly across the entire surface in the in-plane direction. In the second layer of the visible light sensor 210, the readout circuits 215 are arranged evenly corresponding to the two photoelectric conversion units 213A, 213A. In the third layer of the visible light sensor 210, the aperture S1 is also provided evenly corresponding to the two photoelectric conversion units 213A, 213A. In the projection plane in the direction of the optical axis, the portion where the readout circuits 215 are not arranged corresponds to the aperture S1. Read circuits 215, 216 may be arranged on both sides of the opening S1, or read circuits 215, 215 may be arranged, or read circuits 216, 216 may be arranged. In other words, the opening S1 is defined by read circuit 215 and / or read circuit 216.

[0024] The substrate 214 is provided with a photoelectric conversion unit 213A as a photodiode and readout circuits 215, 216 (transistors). Light transmitted through the photoelectric conversion unit 213A is configured to enter an opening S1 provided in the wiring 217A (217B) of the wiring layer 217. The readout circuits 215, 216 are shielded from light transmitted through the microlens 211. Wiring such as control lines and signal lines is provided in the wiring layer 217, and this wiring is arranged to avoid the opening S1. Similarly, wiring such as control lines and signal lines is provided in the wiring layer 222, and this wiring is arranged to avoid the opening S1. The photoelectric conversion unit 221A as a photodiode is provided on the substrate 230 which is joined to the substrate 214, and is configured to enter light that has passed through the opening S1. Wiring such as control lines and signal lines is provided in the wiring 222A, and this wiring is arranged to avoid the opening S2. In this embodiment, the photoelectric conversion unit 221A converts light that has passed through the photoelectric conversion unit 213A and through the aperture S1 defined by the readout circuit 215 and the readout circuit 216 into photoelectric light. The photoelectric conversion unit 221A also converts light that has passed through the aperture S2 formed by the wiring 222A into photoelectric light.

[0025] As shown in Figure 5, the light-receiving area of ​​one photoelectric conversion unit 221A may be the same as the sum of the light-receiving areas of multiple photoelectric conversion units 213A, or the light-receiving area of ​​one photoelectric conversion unit 221A may be the same as the light-receiving area of ​​one photoelectric conversion unit 213A.

[0026] Figure 6 is a partially schematic diagram showing a three-layer image sensor according to the second embodiment, and Figure 7 is a partially cross-sectional view of the image sensor in Figure 6. The configuration of the image sensor 200B in Figure 6 is basically the same as the configuration of the image sensor 200A in Figure 3, and the main differences are described below.

[0027] The image sensor 200B, similar to the first embodiment, includes a visible light sensor 210 and an infrared light sensor 220. The image sensor 200B includes a substrate 241 provided between the visible light sensor 210 and the infrared light sensor 220, and the substrate 241 has a wiring layer 242 and a wiring layer 243. The substrate 241 is provided between substrate 214 and substrate 230, and through electrodes 241a, composed of TSV or the like, are formed on the substrate 241. The wiring layer 242 is provided on the infrared light sensor 220 side of the substrate 241, is provided between substrate 241 and wiring layer 222, and has wiring 242A for outputting from the photoelectric conversion unit 221B to the readout circuit 244. The wiring layer 243 is provided on the visible light sensor 210 side of the substrate 241, is provided between substrate 241 and wiring layer 217, and has wiring 243A. The wirings 242A and 243A may be composed of multilayer wiring.

[0028] Wiring 222A of wiring layer 222 is connected to wiring 242A of wiring layer 242. Wiring 242A is connected to wiring 243A of wiring layer 243 via through electrode 241a. Wiring 243A is connected to wiring 217A of wiring layer 217.

[0029] The wiring layer 217 has signal lines, which will be described later, that output the signal read by the read circuit 215 and the signal read by the read circuit 244. The wiring layer 217 is provided between the substrate 214 and the wiring layer 243 in the optical axis LD of the microlens 211.

[0030] In the image sensor 200B, the photoelectric conversion unit 213A is provided on substrate 214 (first substrate), and the photoelectric conversion unit 221B is provided on substrate 230. The light-receiving layer 221 is provided on substrate 230 (second substrate), which is bonded to substrate 241. The readout circuit 244 is provided on substrate 241 (third substrate), which is positioned between substrate 214 and substrate 230. Note that the readout circuit 244 may include circuits such as transistors provided on substrate 241. The readout circuit 215 is provided on substrate 214. That is, the readout circuit 215 and the readout circuit 244 are provided on different substrates. In this way, in the optical axis LD of the microlens 211, substrates 214, 241, and 230 are stacked (bonded) to each other in this order, and the readout circuit 215 on substrate 214 and the readout circuit 244 on substrate 241 are electrically connected.

[0031] The readout circuit 215 is located on the microlens 211 side of the photoelectric conversion unit 221B. Similarly, the readout circuit 244 is also located on the microlens 211 side of the photoelectric conversion unit 221B. Furthermore, in the optical axis direction LD of the microlens 211, the photoelectric conversion unit 213A, the readout circuit 215, the readout circuit 244, and the photoelectric conversion unit 221B are arranged in this order.

[0032] The readout circuit 244 is preferably provided on the readout circuit 215 side (wiring layer 217 side) of the substrate 241 in the optical axis direction LD of the microlens 211. By providing the readout circuit 244 on the readout circuit 215 side of the substrate 241, the readout circuit 244 and the readout circuit 215 can be easily connected.

[0033] In this embodiment, in the optical axis LD of the microlens 211, a readout circuit 244 is provided in the lower layer (third layer) of the photoelectric conversion unit 213Aa that receives light transmitted through the color filter 212(B), and a light-shielding portion 224 is provided in a part of the infrared light sensor 220 located in the lower layer (second layer) of the readout circuit 244. The light-shielding portion 224 is provided to block transmitted light so that light transmitted through the readout circuit 244 located in the upper layer does not enter the photoelectric conversion unit 221B. An opening S3 is provided in the lower layer (third layer) of the photoelectric conversion unit 213Ab that receives light transmitted through the color filter 212(Gr), and a photoelectric conversion unit 221B is provided in a part of the infrared light sensor 220 located in the lower layer (second layer) of the opening S3. Similarly, an opening S3 is provided in the lower layer (third layer) of the photoelectric conversion unit 213A that receives light transmitted through the color filter 212 (Gb), and a photoelectric conversion unit 221B is provided in a part of the infrared light sensor 220 located in the lower layer (second layer) of the opening S3. A readout circuit 244 is arranged in the lower layer (third layer) of the photoelectric conversion unit 213A that receives light transmitted through the color filter 212 (R), and a light shielding part 224 is provided in a part of the infrared light sensor 220 located in the lower layer (second layer) of the readout circuit 244.

[0034] In this embodiment, the photoelectric conversion unit 221B is provided to convert light transmitted through the opening S1, opening S3, and opening S2 in that order into photoelectric light.

[0035] Figure 8 is a circuit diagram corresponding to a portion of the readout circuits 215 and 244 in Figure 6. Similar to Figure 4, Figure 8 shows a circuit including two photoelectric conversion units 213Aa and 213Ab, which correspond to the right-hand color filters 212(B) and 212(Gr) of the readout circuits 215 and 244 in Figure 6, and a photoelectric conversion unit 221B located below them.

[0036] In the circuit of FIG. 8, a readout circuit 215 is provided on the substrate 214 constituting the first layer, and a readout circuit 244 is provided on the substrate 241 constituting the second layer. The substrate 214 is joined to the substrate 241, and the readout circuit 215 and the readout circuit 244 are connected by connection portions 251 and 252. The pixel portion 20x (see FIG. 4) includes, as the readout circuit 215, a transfer portion TX1, a transfer portion TX2, a reset portion RST, an amplification portion SF, a selection portion SEL (output portion), and an FD region (accumulation portion). Further, the pixel portion 20x includes, as the readout circuit 244 described above, an amplifier OP, a capacitor C, a reset portion RST2, and a selection portion SEL ＩＲ and is provided with. Thus, the circuit configurations of the readout circuit 244 and the readout circuit 215 may be the same as the circuit configuration of FIG. 4, and the readout circuit 244 and the readout circuit 215 may be provided on different substrates.

[0037] FIG. 9 is a schematic diagram showing an example of joining of the readout circuit 244 and the readout circuit 215 of FIG. 5. In FIG. 9, as an example, two pixel portions 20x (photoelectric conversion portions 213Aa, 213Ab) and 20x (photoelectric conversion portions 213Ac, 213Ad) are used for explanation. In FIG. 9, the symbol Vdd indicates the power supply voltage, and the symbol GND indicates the ground voltage. As shown in FIG. 9, the transfer portion TX1, the transfer portion TX2, the reset portion RST, the selection portion SEL, and the selection portion SEL that constitute one pixel portion 20x ＩＲ are provided. The transfer portion TX1, the transfer portion TX2, the reset portion RST, the selection portion SEL, and the selection portion SEL ＩＲ are respectively connected to the control lines L1, L2, L3, L4, and L5, and are controlled via the connected control lines L1, L2, L3, L4, and L5. Further, a signal line L6 is provided, and the signals read by the readout circuits 215 and 244 are output. The transfer portion TX1, the transfer portion TX2, the reset portion RST, the selection portion SEL, and the selection portion SEL that constitute the other pixel portion 20x ＩＲ are also respectively connected to the control lines L1, L2, L3, and L4, and the signals read by the readout circuits 215 and the readout circuit 244 are output via the signal line L7.

[0038] FIG. 10 is a partial schematic diagram showing a modified example of the imaging device of FIG. 6. The configuration of the imaging device 200C in FIG. 10 is basically the same as the configuration of the imaging device 200B in FIG. 7, and the main differences will be described below.

[0039] The imaging device 200C includes a visible light sensor 210, an infrared light sensor 220 disposed on the side opposite to the light incident direction of the visible light sensor 210, and a wiring structure 240 provided between the visible light sensor 210 and the infrared light sensor 220. The wiring structure 240 has a substrate 241 and a wiring layer 242. The substrate 241 is provided between the substrate 214 and the substrate 230, and no through electrodes are formed on the substrate 241. Also, the readout circuit (second readout unit) 245 is provided on the infrared light sensor 220 side of the substrate 241 in the optical axis direction LD of the microlens 211. Note that the readout circuit 245 may include circuits such as transistors provided on the substrate 241.

[0040] The wiring 222A of the wiring layer 222 is connected to the wiring 242A of the wiring layer 242 in the wiring structure 240. The wiring layer 242 has signal lines for outputting signals read by the readout circuit 245. Also, the wiring layer 217 also has signal lines for outputting signals read by the readout circuit 215. Thus, signal lines for outputting signals read by the readout circuit 215 may be provided in the wiring layer 217, and signal lines for outputting signals read by the readout circuit 245 may be provided in the wiring layer 242.

[0041] As described above, according to the present embodiment, since the readout circuit 215 and the readout circuit 216 are provided between the photoelectric conversion unit 213A and the photoelectric conversion unit 221A in the optical axis direction LD of the microlens 211, the readout circuit 216 that reads a signal based on the charge photoelectrically converted by the photoelectric conversion unit 221A can be joined to the readout circuit 215 that reads a signal based on the charge photoelectrically converted by the photoelectric conversion unit 213A. Therefore, it becomes easy to drive the visible light sensor 210 and the infrared light sensor 220 synchronously, and a visible light signal can be output together with an infrared light signal.

[0042] Also, in the two-layer structure, the photoelectric conversion unit 213A and the readout circuit 216 are provided on the substrate 214, and the photoelectric conversion unit 221A is provided on the substrate 230 joined to the substrate 214 (see FIG. 3). By providing the readout circuit 216 on the substrate 214, the readout circuit 216 can be easily joined to the readout circuit 215, and the thinning of the imaging device 200A can be achieved.

[0043] Also, since the readout circuit 215 is provided on the substrate 214, the readout circuit 216 can be more easily joined to the readout circuit 215 in the two-layer structure.

[0044] The wiring layer 217 is provided between the photoelectric conversion unit 213A and the photoelectric conversion unit 221A in the optical axis direction of the microlens 211. When the visible light sensor 210 is a back-illuminated type, the signal lines for outputting the signal read by the readout circuit 215 as a readout circuit for a BSI type image sensor and the signal read by the readout circuit 216 can be shared, and the circuit configuration can be simplified.

[0045] Also, in the three-layer structure, the photoelectric conversion unit 213A is provided on the substrate 214, the photoelectric conversion unit 221B is provided on the substrate 230, and the readout circuit 244 is provided on the substrate 241 provided between the substrate 214 and the substrate 230 (see FIG. 7). Even when the readout circuit 216 cannot be provided on the substrate 214, the readout circuit 216 can be easily and surely joined to the readout circuit 215.

[0046] The photoelectric conversion unit 221A photoelectrically converts the light that has passed through the opening S1 formed by the readout circuit 216 among the light that has passed through the photoelectric conversion unit 213A, so that the reduction of the transmitted light of the photoelectric conversion unit 213A can be suppressed.

[0047] Further, the photoelectric conversion unit 221A photoelectrically converts the light that has passed through the opening S1 formed by the readout circuits 215 and 216 among the light that has passed through the photoelectric conversion unit 213A, so that the reduction of the incident light to the photoelectric conversion unit 221A by the readout circuits 215 and 216 can be suppressed, and the sensitivity can be improved.

[0048] Furthermore, since the light-receiving area of ​​the photoelectric conversion unit 221A is larger than that of the photoelectric conversion unit 213A, light transmitted through the photoelectric conversion unit 213A can be received by the photoelectric conversion unit 221A with high sensitivity.

[0049] Multiple photoelectric conversion units 213A are provided in the X direction, and the photoelectric conversion unit 221A converts light transmitted through the multiple photoelectric conversion units 213A provided in the X direction into photoelectric energy, thus providing an image sensor composed of a sensor array arranged in one dimension.

[0050] Multiple photoelectric conversion units 213A are provided in the X and Y directions, and the photoelectric conversion unit 221A converts light transmitted through the multiple photoelectric conversion units 213A provided in the X and Y directions into photoelectrics, thereby providing an image sensor 200A composed of a two-dimensionally arranged sensor array.

[0051] The readout circuit 215 reads signals based on the charges converted photoelectrically by the multiple photoelectric conversion units 213A, so it can acquire multiple color information corresponding to multiple wavelengths in the visible light band.

[0052] The readout circuit 215 has an FD region to which charges converted photoelectrically by multiple photoelectric conversion units 213A are transferred, and a selection unit SEL that outputs a signal based on the charges accumulated in the FD region. Therefore, it can output multiple signals corresponding to multiple wavelengths in the visible light band with high accuracy.

[0053] Furthermore, since the photoelectric conversion unit 221A converts light with a wavelength longer than the wavelength of light converted by the photoelectric conversion unit 213A, for example, by receiving visible light in the photoelectric conversion unit 213A and infrared light in the photoelectric conversion unit 221A, it becomes possible to simultaneously acquire color information of the subject and invisible information using near-infrared light using a single image sensor.

[0054] Furthermore, since the camera 100 has a generation unit 111 that generates first image data based on the signal read from the readout circuit 215 and second image data based on the signal read from the readout circuit 216, a highly practical camera 100 that can handle various scenes can be provided.

[0055] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention.

[0056] 20x Pixel section 21 Block signal line 22 Signal line 23 A / D conversion circuit 100 Camera (image sensor) 101 Control unit 102 Image generation unit 104 Recording unit 105 Display unit 110 Camera body 111 Generation unit 120 Shooting lens 200A Image sensor 200B Image sensor 200C Image sensor 210 Visible light sensor 211 Microlens 212 Color filter 213A Photoelectric conversion unit 213Aa Photoelectric conversion unit 213Ab Photoelectric conversion unit 213Ac Photoelectric conversion unit 213Ad Photoelectric conversion unit 214 Substrate 215 Readout circuit 215Aa Circuit 215Ab Circuit 216 Readout circuit 217 Wiring layer 217A Wiring 217Aa Control line 217Ab Signal line 217Ba Control line 217Bb Signal line 217B Wiring 220 Infrared light sensor 221 Light receiving layer 221A Photoelectric conversion unit 221B Photoelectric conversion unit 222 Wiring layer 222A Wiring 224 Light shielding unit 230 Substrate 240 Wiring structure 241 Substrate 241a Through electrode 242 Wiring layer 242A Wiring 243 Wiring layer 243A Wiring 244 Read circuit 245 Read circuit 251 Connection part 252 Connection part

Claims

1. An image sensor comprising: a first substrate having a photoelectric conversion unit that converts light into electric charge, the first photoelectric conversion unit being made of a first inorganic semiconductor material; and a second substrate laminated together with the first substrate, the second substrate having a photoelectric conversion unit that converts light transmitted through the first photoelectric conversion unit into electric charge, the second photoelectric conversion unit being made of a second inorganic semiconductor material different from the first inorganic semiconductor material.

2. An image sensor according to claim 1, comprising: a first readout unit for reading out a signal based on the charge converted by the first photoelectric conversion unit; and a second readout unit for reading out a signal based on the charge converted by the second photoelectric conversion unit.

3. The image sensor according to claim 2, wherein the second readout unit is an image sensor provided on the first substrate.

4. The image sensor according to claim 3, wherein the first readout unit is an image sensor provided on the first substrate.

5. The image sensor according to claim 2, wherein the second readout unit is provided on a third substrate provided between the first substrate and the second substrate in the stacking direction in which the first substrate and the second substrate are stacked.

6. An image sensor according to claim 3, comprising a wiring layer having wiring for outputting the second signal read out by the second readout unit.

7. The image sensor according to claim 6, wherein the wiring outputs the first signal read out by the first readout unit.

8. The image sensor according to claim 7, wherein the wiring includes a first signal line for outputting the first signal and a second signal line for outputting the second signal.

9. The image sensor according to claim 6, wherein the wiring layer is provided between the first substrate and the second substrate in the stacking direction in which the first substrate and the second substrate are stacked.

10. An image sensor according to claim 9, wherein the wiring layer has an opening that allows light transmitted through the first photoelectric conversion unit to enter the second photoelectric conversion unit.

11. The image sensor according to claim 8, wherein the first substrate has a signal processing unit that performs signal processing on the second signal.

12. The image sensor according to claim 11, wherein the signal processing unit performs signal processing on the first signal read out by the first readout unit.

13. An image sensor according to claim 11, wherein the signal processing unit has a conversion unit that converts the second signal into a digital signal.

14. The image sensor according to claim 13, wherein the conversion unit converts the first signal read out by the first readout unit into a digital signal.

15. An image sensor according to claim 5, comprising a first wiring layer having wiring for outputting the second signal read out by the second readout unit.

16. The image sensor according to claim 15, wherein the wiring outputs the first signal read out by the first readout unit.

17. The image sensor according to claim 16, wherein the wiring includes a first signal line for outputting the first signal and a second signal line for outputting the second signal.

18. An image sensor according to claim 15, wherein the first wiring layer is provided between the first substrate and the second substrate in the stacking direction.

19. An image sensor according to claim 18, wherein the first wiring layer is provided between the first substrate and the third substrate in the stacking direction.

20. The image sensor according to claim 18, wherein the second readout unit has a first aperture that causes light transmitted through the first photoelectric conversion unit to enter the second photoelectric conversion unit.

21. The image sensor according to claim 20, wherein the first wiring layer has a second aperture that allows light transmitted through the first photoelectric conversion unit to enter the second photoelectric conversion unit.

22. An image sensor according to claim 18, comprising: a second wiring layer that outputs a signal based on the charge converted by the second photoelectric conversion unit to the first wiring layer; a third wiring layer that outputs a signal based on the charge converted by the second photoelectric conversion unit to the second readout unit; and a connection unit that electrically connects the second wiring layer and the third wiring layer.

23. An image sensor according to claim 22, wherein the third substrate, the second wiring layer, and the third wiring layer are stacked in the order of the second wiring layer, the third substrate, and the third wiring layer in the stacking direction, and the connection portion is a through electrode that penetrates the third substrate and electrically connects the second wiring layer and the third wiring layer.

24. The image sensor according to claim 18, wherein the first substrate has a signal processing unit that performs signal processing on the second signal.

25. The image sensor according to claim 24, wherein the signal processing unit performs signal processing on the first signal read out by the first readout unit.

26. The image sensor according to claim 24, wherein the signal processing unit has a conversion unit that converts the second signal into a digital signal.

27. The image sensor according to claim 26, wherein the conversion unit converts the first signal read out by the first readout unit into a digital signal.

28. An image sensor according to claim 1, wherein the second photoelectric conversion unit converts light transmitted through the first photoelectric conversion unit and the third photoelectric conversion unit, which is made of the first inorganic semiconductor material and converts light into electric charge.

29. An image sensor according to claim 28, wherein the light-receiving area of ​​the second photoelectric conversion unit is larger than the light-receiving area of ​​the first photoelectric conversion unit.

30. An image sensor according to claim 28, wherein the third photoelectric conversion unit is arranged in a first direction alongside the first photoelectric conversion unit.

31. An image sensor according to claim 30, comprising a photoelectric conversion unit for converting light into electric charge, the photoelectric conversion unit comprising a fourth photoelectric conversion unit made of the first inorganic semiconductor material, wherein the fourth photoelectric conversion unit is arranged alongside the first photoelectric conversion unit in a second direction different from the first direction, and the second photoelectric conversion unit converts light transmitted through the first photoelectric conversion unit, the third photoelectric conversion unit, and the fourth photoelectric conversion unit into electric charge.

32. An image sensor according to claim 28, wherein the first readout unit reads out a signal based on the charge converted by the first photoelectric conversion unit and the third photoelectric conversion unit.

33. The image sensor according to claim 32, wherein the first readout unit includes a floating diffusion to which the charge converted in the first photoelectric conversion unit and the third photoelectric conversion unit is transferred, and an output unit that outputs a signal based on the charge accumulated in the floating diffusion unit.

34. An image sensor according to claim 1, wherein the second photoelectric conversion unit converts light with a wavelength longer than the wavelength of light converted by the first photoelectric conversion unit into an electric charge.

35. An image sensor according to claim 1, wherein the first photoelectric conversion unit converts visible light into electric charge, and the second photoelectric conversion unit converts infrared light into electric charge.

36. An image sensor according to claim 1, wherein the second inorganic semiconductor material is InGaAs.

37. An image sensor according to claim 2, wherein the first readout section and the second readout section are shielded from light so as not to be incident on them.

38. An image sensor comprising: a first substrate having a first photoelectric conversion unit that converts visible light into electric charge and a first readout unit that reads out the electric charge converted by the first photoelectric conversion unit; and a second substrate having a second photoelectric conversion unit that converts infrared light transmitted through the first photoelectric conversion unit into electric charge, wherein the first substrate has a second readout unit that reads out the electric charge converted by the second photoelectric conversion unit.

39. An imaging device comprising the image sensor described in any one of claims 1 to 38.

40. An imaging device according to claim 39, comprising a generation unit that generates first image data based on a signal read out from a first reading unit that reads out a signal based on a charge converted by the first photoelectric conversion unit, and second image data based on a signal read out from a second reading unit that reads out a signal based on a charge converted by the second photoelectric conversion unit.

41. An imaging device according to claim 40, comprising a display unit that displays an image based on the first image data and an image based on the second image data.

42. An imaging device according to claim 40, comprising a recording unit for recording an image based on the first image data and an image based on the second image data.

Images