WO2020070887A1 - Solid-state imaging device - Google Patents

Solid-state imaging device

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Publication number
WO2020070887A1
WO2020070887A1 PCT/JP2018/037422 JP2018037422W WO2020070887A1 WO 2020070887 A1 WO2020070887 A1 WO 2020070887A1 JP 2018037422 W JP2018037422 W JP 2018037422W WO 2020070887 A1 WO2020070887 A1 WO 2020070887A1
Authority
WO
WIPO (PCT)
Prior art keywords
photoelectric conversion
substrate
region
filter
imaging device
Prior art date
Application number
PCT/JP2018/037422
Other languages
French (fr)
Japanese (ja)
Inventor
祐輔 山本
友作 小山
嘉晴 安食
良章 竹本
Original Assignee
オリンパス株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by オリンパス株式会社 filed Critical オリンパス株式会社
Priority to PCT/JP2018/037422 priority Critical patent/WO2020070887A1/en
Publication of WO2020070887A1 publication Critical patent/WO2020070887A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
    • H04N23/12—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths with one sensor only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith

Definitions

  • the present invention relates to a solid-state imaging device, and more particularly, to an imaging device that simultaneously acquires a visible light image and an infrared light image.
  • FIG. 1 is a cross-sectional view of such an imaging device.
  • the imaging device 100 includes a first substrate 101, a second substrate 102, a color filter 103, and a connection unit 104.
  • Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and outputs a pixel signal corresponding to the amount of received light.
  • RGB color filters 103 are formed on the light receiving surface side (upper side in the figure) of the first substrate.
  • the first substrate 101 is a back-illuminated (BSI) imaging substrate, and the thickness of the first substrate 101 is as thin as about several ⁇ m. Therefore, part of the light incident from the light receiving surface side of the first substrate 101 is transmitted, and is incident on the light receiving surface side of the second substrate 102.
  • silicon has a high light absorptivity for light having a short wavelength, and a low light absorptivity of silicon for light having a long wavelength. Therefore, in the first substrate 101 having a small thickness, part of infrared light having a long wavelength is transmitted without being absorbed, and is incident on the second substrate 102. Therefore, the first substrate 101 can detect visible light, and the second substrate 102 can detect infrared light. As described above, the visible light image and the infrared light image can be simultaneously observed using the first substrate 101 and the second substrate 102.
  • BSI back-illuminated
  • FIG. 16 is a diagram showing details of a cross section of an imaging device according to the related art.
  • Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and each pixel includes a photoelectric conversion layer and a wiring layer.
  • the first substrate 101 includes a first photoelectric conversion layer 111 and a first wiring layer 121.
  • the second substrate 102 includes a second photoelectric conversion layer 112 and a second wiring layer 122.
  • a photoelectric conversion unit (photodiode) is formed in the photoelectric conversion layer, and receives light transmitted through the RGB color filter 103 and performs photoelectric conversion.
  • a first photoelectric conversion unit 113 is formed in the first photoelectric conversion layer 111.
  • a second photoelectric conversion unit 114 is formed on the second photoelectric conversion layer 112.
  • the wiring layer is formed by stacking layers composed of a plurality of wirings 123, and each layer is insulated by an interlayer insulating film 124.
  • the wiring 123 and the MOS transistor 115 include a control line for driving each pixel and a circuit for reading a signal of each pixel.
  • the ratio of wiring in each pixel increases, and the aperture ratio of each pixel decreases. Therefore, the amount of light incident on the second photoelectric conversion layer 112 further decreases, and the sensitivity of the second photoelectric conversion unit 114 further decreases.
  • the present invention suppresses a decrease in the amount of light incident on a second photoelectric conversion layer (lower photodiode) in a stacked imager (imaging device) that simultaneously detects visible light and infrared light. It is an object of the present invention to provide a pixel structure for performing the above.
  • a first substrate having a plurality of first photoelectric conversion units and a second substrate having a plurality of second photoelectric conversion units are provided so as to be stacked on the first substrate.
  • a solid-state imaging device comprising: a substrate; and wherein in the first substrate, at least two first photoelectric conversion units among the plurality of first photoelectric conversion units form a first photoelectric conversion group;
  • a plurality of first photoelectric conversion units included in the first photoelectric conversion group share one floating diffusion unit, and one of the plurality of first photoelectric conversion units and one of the first photoelectric conversion units and its surroundings Wherein there is a first high-density region in which the sum of the area of the wiring and the area of the transistor is higher than that of the remaining first photoelectric conversion units among the plurality of first photoelectric conversion units;
  • the plurality of second photoelectric conversion units are A solid-state imaging device, wherein at least one second photoelectric conversion unit is provided corresponding to the first photoelectric conversion group, and the plurality of second photoelectric conversion units exist below
  • At least two second photoelectric conversion units among the plurality of second photoelectric conversion units form a second photoelectric conversion group, and a plurality of second photoelectric conversion groups included in the second photoelectric conversion group are included.
  • One floating diffusion portion is shared by the second photoelectric conversion portions, and the sum of the area of the wiring and the transistor is one of the plurality of second photoelectric conversion portions in and around the second photoelectric conversion portion.
  • the second high-density region of the second photoelectric conversion unit having a higher density than the remaining second photoelectric conversion unit may be located at the same position as the first high-density region.
  • the first high-density region may include at least an amplification transistor.
  • the second high-density region may include at least an amplification transistor.
  • a color filter that is disposed on the first substrate and has a transmission band in a visible region and an infrared region, wherein the plurality of first photoelectric conversion units are configured to reduce an exposure amount of light transmitted through the color filter.
  • the signal charge may be output.
  • the color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region, wherein the first high-density region includes the R filter. May be provided at a surface position of the first photoelectric conversion unit immediately below the first photoelectric conversion unit.
  • the first wiring layer of the first substrate and the second wiring layer of the second substrate are provided so as to face each other, and in the first substrate, the wiring in the first wiring layer is
  • the second wiring board may be arranged in the second high-density region, and the wiring in the second wiring layer may be arranged in the second high-density region in the second substrate.
  • a first wiring layer of the first substrate is provided below the first photoelectric conversion unit, and a second wiring layer of the second substrate is provided below the second photoelectric conversion unit.
  • the wiring in the first wiring layer may be arranged in the first high-density region.
  • a filter that cuts visible light and transmits infrared light may be provided between the first substrate and the second substrate.
  • the color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region.
  • the first photoelectric conversion unit includes the color filter. And a thickness of the first photoelectric conversion layer in a region where the B filter is disposed and a thickness of the first photoelectric conversion layer in a region where the G filter is disposed. The thickness of the first photoelectric conversion layer in a region where the R filter is arranged may be thicker than the thickness.
  • the color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region.
  • the second photoelectric conversion unit includes a second photoelectric conversion unit. The second photoelectric conversion unit corresponding to the R filter may not be present in the second photoelectric conversion layer, which is disposed in a photoelectric conversion layer.
  • Pixel structure in a stacked imager (imaging device) that simultaneously detects visible light and infrared light, a decrease in the amount of light incident on the second photoelectric conversion layer (lower photodiode) is suppressed.
  • Pixel structure can be provided.
  • FIG. 2 is a cross-sectional view illustrating a cross section of the imaging device according to the embodiment of the present invention.
  • FIG. 2 is a schematic diagram illustrating an arrangement of pixels included in a first substrate on which a color filter is formed in an embodiment of the present invention.
  • FIG. 3 is a schematic diagram illustrating an arrangement of pixels included in a second substrate in the embodiment of the present invention.
  • FIG. 4 is a schematic diagram illustrating an arrangement relationship between pixels in a set of unit pixel regions included in a first substrate and pixels included in a second substrate in the embodiment of the present invention.
  • 5 is a graph illustrating transmission characteristics of a color filter according to the embodiment of the present invention. It is an image figure of the imaging device concerning a 1st embodiment of the present invention.
  • FIG. 2 is a diagram illustrating a circuit configuration related to a pixel unit in a unit pixel region of the imaging device according to the first embodiment of the present invention.
  • FIG. 2 is a diagram illustrating an arrangement diagram of a color filter having a unit pixel area reduction of the imaging device according to the first embodiment of the present invention.
  • FIG. 2 is a diagram illustrating a pixel layout of a unit pixel region of the imaging device according to the first embodiment of the present invention.
  • FIG. 6 is a diagram illustrating details of a cross section of the imaging device according to Modification Example 1 of the first embodiment of the present invention.
  • FIG. 3 is a diagram illustrating an example of spectral sensitivity of RGB pixels. It is the graph which plotted the light quantity at the time of 450 nm, 530 nm, 620 nm, and 800 nm light having traveled arbitrary distance in Si.
  • FIG. 11 is a diagram illustrating details of a cross section of an imaging device according to a conventional technique.
  • FIG. 1 is a cross-sectional view showing a cross section of an imaging device 100 (solid-state imaging device) according to an embodiment of the present invention.
  • the imaging device 100 includes a first substrate 101, a second substrate 102, a color filter 103 (first filter), and a connection unit 104.
  • Each of the first substrate 101 and the second substrate 102 is formed on a silicon chip and has a plurality of pixels.
  • An RGB color filter 103 is provided on the light receiving surface side of the first substrate 101. The arrangement of the color filters 103 and the wavelength of light transmitted by the color filters 103 will be described later.
  • the color filter 103 has transmission bands in the visible region and the infrared region.
  • the color filter 103 is made of an organic material (pigment), the red color filter (R filter) transmits red visible light and infrared light, and the green color filter (G filter) is green visible light.
  • a blue color filter (B filter) have a characteristic of transmitting blue visible light and infrared light.
  • the first substrate 101 and the second substrate 102 are stacked.
  • the second substrate 102 is disposed on the side opposite to the light receiving surface of the first substrate 101.
  • the light receiving surface of the second substrate 102 is on the side where the first substrate 101 exists.
  • a connection portion 104 is formed between the first substrate 101 and the second substrate 102, and the first substrate 101 and the second substrate 102 are electrically connected to each other through the connection portion 104. ing. That is, the first substrate 101 and the second substrate 102 are bonded to each other via the connection portion 104.
  • the first substrate 101 is a back-illuminated imaging substrate, and the thickness of the first substrate 101 is as thin as about several ⁇ m. Therefore, part of the light incident from the light receiving surface side of the first substrate 101 is transmitted, and is incident on the light receiving surface side of the second substrate 102.
  • the light absorption of silicon differs depending on the wavelength.
  • the light absorptivity of silicon for light with a short wavelength is high, and the light absorptivity of silicon for light with a long wavelength is low. That is, in the thin first substrate 101 having a thickness of about 3 ⁇ m, of light incident on the imaging device 100, visible light having a short wavelength is almost absorbed, but infrared light having a long wavelength is not partially absorbed. Through the first substrate.
  • the second substrate 102 is a front-illuminated imaging substrate and is thicker than the first substrate 101.
  • the second substrate 102 detects infrared light transmitted through the first substrate 101.
  • the first substrate 101 is not limited to a back-illuminated imaging substrate, and may be any substrate that absorbs visible light and transmits infrared light.
  • FIG. 2 is a schematic diagram showing an arrangement of pixels included in the first substrate 101 provided with the color filters 103 in the embodiment of the present invention.
  • an example is shown in which a total of 32 pixels are arranged two-dimensionally in 4 rows and 8 columns.
  • the number and arrangement of the pixels included in the first substrate 101 are not limited to the illustrated example, but may be any number and arrangement.
  • the color filters 103 are arranged in a Bayer array, and four pixels vertically and horizontally adjacent to each other are defined as a set of unit pixel areas 200. Therefore, as shown in the figure, one set of unit pixel regions 200 has one pixel 201 provided with a color filter 103 that transmits red and infrared light wavelength regions, and transmits one green pixel and infrared light wavelength region. And a pixel 203 provided with a color filter 103 that transmits the wavelength region of blue and infrared light.
  • Each of the pixels 201 to 203 included in the first substrate 101 includes a photoelectric conversion element (first photoelectric conversion element) and a signal readout circuit.
  • Each photoelectric conversion element outputs a first signal charge corresponding to an exposure amount to a readout circuit.
  • the signal readout circuit outputs the first signal charge output from the photoelectric conversion element as a first electric signal.
  • FIG. 3 is a schematic diagram showing an arrangement of pixels included in the second substrate 102 in the embodiment of the present invention.
  • an example is shown in which a total of 32 pixels are arranged two-dimensionally in 4 rows and 8 columns.
  • the number and arrangement of the pixels included in the second substrate 102 are not limited to the illustrated example, but may be any number and arrangement.
  • Each of the pixels 301 to 303 included in the second substrate 102 includes a photoelectric conversion element (second photoelectric conversion element) and a signal readout circuit.
  • Each photoelectric conversion element outputs a second signal charge corresponding to the exposure amount to the readout circuit.
  • the signal readout circuit outputs the second signal charge output from the photoelectric conversion element as a second electric signal.
  • FIG. 4 shows an arrangement relationship between pixels 201 to 203 of a set of unit pixel regions 200 included in the first substrate 101 and pixels 301 to 303 included in the second substrate 102 in the embodiment of the present invention.
  • the pixel 301 is disposed at a position where the infrared light transmitted through the pixel 201 provided with the color filter 103 transmitting red light and infrared light is incident.
  • the pixel 302 is arranged at a position where the infrared light transmitted through the pixel 202 provided with the color filter 103 transmitting the green light and the infrared light is incident.
  • the pixel 303 is disposed at a position where the infrared light transmitted through the pixel 203 provided with the color filter 103 transmitting blue light and infrared light is incident. That is, the pixels 201 to 203 included in the first substrate 101 and the pixels 301 to 303 included in the second substrate 102 have a one-to-one correspondence.
  • FIG. 5 is a graph showing the transmission characteristics of the color filter 103 according to the embodiment of the present invention.
  • the horizontal axis of the graph shown in the drawing represents the wavelength, and the vertical axis represents the transmittance of the color filter 103 at each wavelength.
  • the line 511 indicates that the blue color filter 103 transmitting the blue light and the infrared light has a wavelength of about 400 nm to 500 nm (blue light) and a wavelength of about 700 nm or more (blue). Infrared light).
  • the line 512 indicates that the green color filter 103 transmitting the green light and the infrared light has a wavelength of about 500 nm to 600 nm (green light) and a wavelength of about 700 nm or more (infrared light). ).
  • a line 513 indicates that the green color filter 103 transmitting red light and infrared light transmits light having a wavelength of about 600 nm or more (red light and infrared light).
  • the light source uses illumination light including wavelengths from a visible region to an infrared region. Then, an illuminating light is applied to a target object such as a living tissue or a finger, and the transmitted light or the reflected light is incident on the imaging device 100.
  • the red color filter 103 transmits red light and infrared light.
  • the green color filter 103 transmits green light and infrared light.
  • the blue color filter 103 transmits blue light and infrared light.
  • Each of the pixels 201 to 203 of the first substrate 101 detects visible light transmitted through each of the color filters 103 and outputs a first electric signal. Specifically, the pixel 201 provided with the red color filter 103 outputs a first electric signal corresponding to red light. The pixel 202 provided with the green color filter 103 outputs a first electric signal corresponding to green light. The pixel 203 provided with the blue color filter 103 outputs a first electric signal corresponding to blue light.
  • a processing unit (not shown) generates a visible light image based on the first electric signal output from each of the pixels 201 to 203. Strictly speaking, the first substrate 101 absorbs not only visible light but also infrared light.
  • the first electric signal output from the first substrate 101 includes, in addition to the visible light component, a slightly detected infrared light component.
  • the infrared light considered in the present embodiment is weak light such as fluorescence, and light that is weaker than visible light enters the substrate. Therefore, in the first signal, a signal generated by visible light is more dominant than a signal generated by infrared light. Therefore, in this specification, description is made such that each pixel of the first substrate 101 detects visible light.
  • the infrared light transmitted through the first substrate 101 is incident on the second substrate 102.
  • Each of the pixels 301 to 303 included in the second substrate 102 has sensitivity at least in the infrared region.
  • Each of the pixels 301 to 303 of the second substrate 102 outputs a second electric signal according to light having a wavelength of infrared light.
  • a processing unit (not shown) generates an infrared light image based on the second electric signal output from each of the pixels 301 to 303.
  • the first substrate 101 and the second substrate 102 are stacked. Further, the first substrate 101 transmits infrared light. Accordingly, the pixels 201 to 203 included in the first substrate 101 can output the first electric signal based on the visible light. Further, the pixels 301 to 303 included in the second substrate 102 can output a second electric signal based on infrared light. Further, a visible light image can be generated from the first electric signal, and an infrared light image can be generated from the second electric signal.
  • the imaging device 100 can simultaneously output a first electric signal capable of generating a visible light image and a second electric signal capable of generating an infrared light image.
  • the imaging device 100 according to the embodiment of the present invention does not require a dichroic mirror, a plurality of lenses, and imaging devices for detecting visible light and detecting infrared light. Therefore, size reduction and cost reduction of the device can be realized. Therefore, according to the embodiment of the present invention, the imaging device 100 can simultaneously acquire the visible light image and the infrared light image at low cost.
  • FIG. 6 is an image diagram of the imaging device according to the first embodiment of the present invention.
  • the layers of the color filter 103, the first substrate 101, and the second substrate 102 are arranged in order from the upper side of the drawing (the light receiving surface side of the first substrate).
  • a unit pixel region 200 is configured from a plurality of pixels (four pixels of 2 ⁇ 2 pixels in the present embodiment), and the entire photoelectric conversion layer is configured by repeating the unit pixel region.
  • FIG. 7 is a diagram showing details of a cross section of the imaging device according to the first embodiment of the present invention.
  • Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and each pixel includes a photoelectric conversion layer and a wiring layer.
  • the first substrate 101 includes a first photoelectric conversion layer 111 and a first wiring layer 121.
  • the second substrate 102 includes a second photoelectric conversion layer 112 and a second wiring layer 122.
  • a photoelectric conversion unit (photodiode) is formed in the photoelectric conversion layer, and receives light transmitted through the RGB color filter 103 and performs photoelectric conversion.
  • a first photoelectric conversion unit 113 is formed in the first photoelectric conversion layer 111.
  • a second photoelectric conversion unit 114 is formed on the second photoelectric conversion layer 112.
  • the wiring layer is formed by stacking layers composed of a plurality of wirings 123, and each layer is insulated by an interlayer insulating film 124.
  • the wiring 123 and the MOS transistor 115 include a control line for driving each pixel and a circuit for reading a signal of each pixel.
  • wirings and transistors are laid under one pixel (R pixel in the present embodiment) in the unit pixel region. Therefore, in order to minimize wiring and transistors below the other pixels (the G pixel and the B pixel), the ratio of the wiring in the pixel is reduced, and a space is generated as shown in FIG.
  • the light transmitted without being absorbed by the first photoelectric conversion layer 111 forms the first wiring layer 121 of the first substrate 101 before being incident on the second photoelectric conversion layer 112 of the second substrate 102.
  • the light is reflected on the wirings to be formed and the wirings forming the second wiring layer 122 in the second substrate 102.
  • the ratio of the wiring in the G pixel and the B pixel is reduced, the amount of light incident on the second substrate 102 in the G pixel and the B pixel is increased. Thereby, the sensitivity of the second photoelectric conversion unit 114 is improved in the G pixel and the B pixel.
  • FIG. 8 is a diagram illustrating a circuit configuration related to a pixel unit in a unit pixel region of the imaging device according to the present embodiment. Note that the circuit configuration is common to the first substrate and the second substrate.
  • one photodiode (pixel) PD1 to PD4 shares one floating diffusion portion (FD).
  • the four photodiodes share a reset transistor (r-Tr), an amplification transistor (a-Tr), and a selection transistor (s-Tr) other than the transfer transistors (t-Tr1 to t-Tr4). is there.
  • the photodiodes PD1 to PD4 of each pixel accumulate charges corresponding to the amount of incident light.
  • the electric charge accumulated in each photodiode is transferred to the floating diffusion section via the transfer transistor of each pixel.
  • the amplification transistor forms a current source and a source follower via the selection transistor, and outputs an electric signal corresponding to the electric charge accumulated in the floating diffusion portion to the vertical signal line as an output signal. Note that the reset transistor resets the charge in the floating diffusion portion to the power supply voltage VDD.
  • FIG. 9 is a diagram illustrating an arrangement diagram of a color filter of a unit pixel area of the imaging apparatus according to the present embodiment.
  • FIG. 10 is a diagram illustrating a pixel layout of a unit pixel region of the imaging device according to the present embodiment. Note that the unit pixel region has a common layout configuration for the first substrate 101 and the second substrate 102, and FIG. 10 is an image diagram of the unit pixel area on the first substrate 101 or the second substrate 102.
  • the reset transistor (r-Tr) is formed with the diffusion regions 212 and 213 as a source and a drain, respectively, and with a gate electrode. Further, the amplification transistor (a-Tr) is formed to have the diffusion regions 214 and 215 as drains and sources, respectively, and to have a gate electrode. Further, the selection transistor (s-Tr) is formed with the diffusion regions 215 and 216 as drains and sources, respectively, and having a gate electrode.
  • the photodiodes PD1 to PD4 of each pixel are connected to respective transfer transistors (t-Tr1 to t-Tr4). That is, the photodiodes PD1 to PD4 of each pixel are connected to the floating diffusion unit 211 via the transfer transistor.
  • a thick line 217 in the drawing is a wiring of a floating diffusion (FD wiring), and the FD wiring electrically connects the floating diffusion portion 211 to the gate electrode of the amplification transistor and the source 212 of the reset transistor.
  • the source of the amplification transistor and the drain of the selection transistor are formed by a common diffusion region 215, and are electrically connected.
  • the source of the selection transistor is electrically connected to the vertical signal line.
  • the drain 213 of the reset transistor and the drain 214 of the amplification transistor are electrically connected to the power supply VDD.
  • a signal line (not shown) for controlling the transfer transistor is wired along the first substrate 101 or the second substrate 102 along the horizontal direction (column direction), and is connected to the gate electrode of each transfer transistor. ing.
  • a signal line for controlling the reset transistor, the first substrate 101 or the second substrate 102 is arranged along the horizontal direction (column direction), and is connected to the gate electrode of the reset transistor.
  • a signal line for controlling the selection transistor is arranged along the first substrate 101 or the second substrate 102 along the horizontal direction (column direction), and is connected to the gate electrode of the selection transistor.
  • the transfer transistor is disposed in each pixel, but the amplification transistor, the reset transistor, and the selection transistor It is arranged at the pixel (R pixel, PD2 in FIG. 10) on which the color filter is arranged.
  • the proportion of wiring occupied by B pixels (pixels on which a color filter of B is arranged, PD3 in FIG. 10) and G pixels (pixels on which a color filter of G is arranged, PD1 and PD4 in FIG. 10) other than the R pixel decreases I do. Therefore, the amount of light incident on the pixel (PD3) provided with the B color filter and the pixels (PD1 and PD4) provided with the G color filter in the second photoelectric conversion unit 114 increases, and The sensitivity is improved.
  • the photodiode PD2 of the pixel provided with the R color filter in the second photoelectric conversion unit 114 becomes unnecessary, and the other photodiodes PD1 and PD3 , PD4 can be arranged so as to increase the area. Accordingly, the photodiode area of the pixel provided with the B color filter and the pixel provided with the G color filter in the second photoelectric conversion layer 112 increases, and the amount of light incident on these photodiodes further increases. And further improvement in sensitivity can be expected.
  • circuits and transistors are spread under the R pixels. It is sufficient that at least a transfer transistor is disposed in a portion other than the R pixel, and a reset transistor, a selection transistor, and the like are disposed immediately below the R pixel. Further, the signal of the second pixel area (PD2) below the R pixel in FIG. 10 can be corrected using the signal of the adjacent unit pixel area (not shown) in the second photoelectric conversion unit.
  • the aperture ratio of the B pixel and the G pixel other than the R pixel is improved (the wiring area is reduced), and the amount of light incident on the second photoelectric conversion unit is increased. Then, as compared with the conventional structure, the SN ratio of the signal detected by the second photoelectric conversion unit is improved. In the region under the B pixel and the G pixel in the second photoelectric conversion unit, the rate of laying down the transistors is reduced, so that the PD region can be expanded, which leads to an improvement in sensitivity.
  • FIG. 11 is a diagram illustrating details of a cross section of the imaging device according to the first modification.
  • a filter visible light cut filter
  • FIG. 7 The difference from the first embodiment shown in FIG. 7 is that a filter (visible light cut filter) that cuts visible light and transmits only infrared light is inserted between the first substrate 101 and the second substrate 102.
  • the interlayer multilayer film 130 is formed. That is, the interlayer multilayer film 130 including the visible light cut filter is provided between the upper pixel and the lower pixel.
  • the second photoelectric conversion unit 114 can efficiently detect infrared light.
  • FIG. 12 is a diagram illustrating details of a cross section of the imaging device according to the second modification.
  • the difference from the first embodiment shown in FIG. 7 is that, on the second substrate 102, the positions of the second wiring layer 122 and the second photoelectric conversion layer 112 are switched. That is, the second substrate 102 of the present modified example has a backside illumination (BSI) structure.
  • BSA backside illumination
  • the second wiring layer 122 which has been a factor of reflection and scattering, is eliminated, so that the amount of light incident on the second photoelectric conversion unit 114 increases.
  • the sensitivity of the second photoelectric conversion unit 114 is improved. Further, the infrared light transmitted through the second photoelectric conversion unit 114 is reflected by the wiring in the second wiring layer 122 and is incident on the second photoelectric conversion unit 114 again. The sensitivity of 114 is further improved.
  • FIG. 13 is a diagram illustrating details of a cross section of the imaging device according to the second embodiment of the present invention.
  • the difference from the first embodiment shown in FIG. 7 is that the thickness of the first photoelectric conversion layer 111 in the region where the blue color filter is provided and the first photoelectric conversion layer 111 in the region where the green color filter is provided Is different from the thickness of the first photoelectric conversion layer 111 in the region where the red color filter is provided. That is, the thickness of the first photoelectric conversion layer 111 is changed for each of the B pixel, the G pixel, and the R pixel.
  • the thickness of the region provided with the blue color filter and the thickness of the region provided with the green color filter are larger than the thickness of the region provided with the red color filter. Should be thinner. That is, the thickness of the first photoelectric conversion layer of the B pixel and the thickness of the first photoelectric conversion layer of the G pixel ⁇ the thickness of the first photoelectric conversion layer of the R pixel.
  • absorption of infrared light in the first photoelectric conversion layer 111 in the region where the blue color filter is provided and the first photoelectric conversion layer 111 in the region where the green color filter is provided is suppressed.
  • the amount of infrared light incident on the second photoelectric conversion layer 112 in the region where the blue color filter is provided and the second photoelectric conversion layer 112 in the region where the green color filter is provided increases, The sensitivity of the second photoelectric conversion layer 112 is improved.
  • the manufacturing method of the above-mentioned imaging device is as follows. First, holes for embedding the light transmitting material 140 are formed by dry-etching the first photoelectric conversion layer 111 in a region where the blue color filter and the green color filter are provided. Next, the light transmitting material 140 is embedded in the hole formed by dry etching.
  • the light transmitting material 140 is formed from a material having a high light transmitting property, and is formed using a transparent material such as SiO 2 or SiN or a transparent resin. After the light transmitting material 140 is embedded, the surface of the first photoelectric conversion layer 111 is flattened in order to form the color filter 103.
  • FIG. 14 is a diagram illustrating an example of the spectral sensitivity of the RGB pixels. That is, the first photoelectric conversion portion 113 in the region where the blue color filter is provided, the first photoelectric conversion portion 113 in the region where the green color filter is provided, and the first photoelectric conversion portion 113 in the region where the red color filter is provided.
  • the wavelengths at which the sensitivity of the first photoelectric conversion unit 113 is highest can be regarded as 450 nm, 530 nm, and 620 nm, respectively.
  • the wavelength of light (infrared light) detected by the second photoelectric conversion unit 114 is 800 nm.
  • FIG. 15 is a graph plotting the light amounts when 450 nm, 530 nm, 620 nm, and 800 nm light travels an arbitrary distance in Si.
  • the vertical axis of the graph indicates the amount of light, and the intensity of light incident on the Si surface is set to 1.
  • the horizontal axis of the graph indicates the distance [um] traveled by the light.
  • the thickness of the Si layer having a general BSI structure is about 3.0 ⁇ m, and at this time, about 25% of 800 nm light is absorbed.
  • the thickness of the Si layer is about 1.0 ⁇ m, about 10% of the 800 nm light is absorbed.
  • the thickness of the Si layer is set to about 1.6 ⁇ m, about 14% of the 800 nm light is absorbed. Therefore, by adjusting the thickness of the Si layer for each pixel, the amount of infrared light absorbed by the upper pixel can be reduced.
  • the first photoelectric conversion layer 111 in the region where the blue color filter is provided is provided.
  • the first photoelectric conversion layer 111 in the region where the green color filter is provided is provided.
  • both the first substrate 101 and the second substrate 102 form a unit pixel region 200 (photoelectric conversion group) from four 2 ⁇ 2 pixels (photoelectric conversion units), and the floating diffusion unit (
  • the present invention is not limited to this. It is sufficient that two or more photodiodes (pixels) on the upper side (first substrate 101) share the FD. That is, on the first substrate 101, at least two pixels (first photoelectric conversion units 113) form a unit pixel region (first photoelectric conversion group), and a plurality of pixels included in the first photoelectric conversion group. It is sufficient that the first photoelectric conversion unit shares one floating diffusion unit.
  • the sum of the area of the wiring and the area of the transistor at one of the first photoelectric conversion units 113 and at any position around the first photoelectric conversion unit 113 is equal to the sum of the area of the plurality of first photoelectric conversion units.
  • the first high-density region in FIG. 10, around the region where the PD 2 is located) that has a higher density than the remaining first photoelectric conversion units may be present.
  • At least one photodiode (pixel) on the lower side (second substrate 102) should correspond to the unit pixel region (first photoelectric conversion group) on the upper side (first substrate 101). That is, on the second substrate 102, it is sufficient that at least one second photoelectric conversion unit is provided corresponding to the first photoelectric conversion group. As described above, a plurality of pixels share the FD in the first substrate 101, but a plurality of pixels do not need to share the FD in the second substrate 102.
  • the second photoelectric conversion unit only needs to exist below the above-described first non-high-density area (the area where PD1, PD3, and PD4 exist in FIG. 10).
  • each pixel on the first substrate 101 and the second substrate 102 has the same size
  • the present invention is not limited to this.
  • the size (pixel size) of a pixel arranged on the first substrate 101 and a pixel arranged on the second substrate 102 may be different.
  • At least two second photoelectric conversion units 114 form a second photoelectric conversion group, and a plurality of second photoelectric conversion units 114 included in the second photoelectric conversion group share one floating diffusion unit.
  • the sum of the area of the wiring and the area of the transistor at one of the second photoelectric conversion units 113 and at any position around the second photoelectric conversion unit 113 among the plurality of second photoelectric conversion units 113 is determined.
  • the second high-density region existing at a higher density than the remaining second photoelectric conversion unit is any one of the first photoelectric conversion unit of the first substrate 101 where the first high-density region exists and one of the first photoelectric conversion unit and its surroundings. It should just be under the position of.
  • the present invention is not limited to this.
  • only the amplification transistor having the largest area may be arranged in the high-density region (first high-density region, second high-density region).
  • the first high-density region is provided at the surface position of the first photoelectric conversion unit immediately below the R filter, but the present invention is not limited to this.
  • the first high-density region may be provided at a surface position of the first photoelectric conversion unit in a region immediately below the G filter.
  • first wiring layer 121 of the first substrate 101 and the second wiring layer 122 of the second substrate 102 are provided to face each other (FIGS. 7, 11, and 13)
  • first substrate 101 wirings (and transistors) in the first wiring layer 121 are arranged in a first high-density region.
  • the wiring (and the transistor) in the second wiring layer 122 is arranged in the second high-density region.
  • a first wiring layer 121 of the first substrate 101 is provided below the first photoelectric conversion unit 113, and a second wiring layer 122 of the second substrate 102 is provided below the second photoelectric conversion unit 114.
  • the wiring (and the transistor) in the first wiring layer 121 is arranged in the first high-density region.
  • the wiring (and the transistor) in the second wiring layer 122 may be arranged in the second high-density region, or the wiring (and the transistor) in the second wiring layer 122 may be arranged.
  • Transistors may be evenly arranged.
  • the photodiode PD2 of the pixel provided with the R filter in the second photoelectric conversion layer 112 becomes unnecessary, the photodiodes PD1, PD3, and PD4 are arranged so that the areas of the other photodiodes PD1, PD3, and PD4 are large. Is also good. That is, the second photoelectric conversion layer 112 may not include the second photoelectric conversion unit (photodiode PD2) corresponding to the R filter.
  • the present invention can be widely applied to a stacked-type imaging device that simultaneously acquires a visible light image and an infrared light image, and suppresses a decrease in the amount of light incident on the second photoelectric conversion layer (lower photodiode). it can.
  • imaging device 101 first substrate 102 second substrate 103 color filter 104 connection portion 111 first photoelectric conversion layer 112 second photoelectric conversion layer 113 first photoelectric conversion portion (pixel) 114 second photoelectric conversion unit (pixel) 115 MOS transistor 121 1st wiring layer 122 2nd wiring layer 123 wiring 124 Interlayer insulating film 130 Interlayer multilayer film (visible light cut filter) 140 light transmitting material 200 unit pixel area (photoelectric conversion group) 201 to 203, 301 to 303 ...
  • Pixel 211 Floating diffusion part 212 to 216 Diffusion area 217 FD wiring PD1, PD3, PD4 Photodiode (area other than high density area) PD2 photodiode (high density area) a-Tr amplifying transistor r-Tr reset transistor s-Tr selection transistor t-Tr1 to t-Tr4 transfer transistor

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Abstract

This solid-state imaging device is provided with: a first substrate that includes a plurality of first photoelectric conversion units; and a second substrate that is disposed so as to be layered on the first substrate and that includes a plurality of second photoelectric conversion units. In the first substrate, at least two of the plurality of first photoelectric conversion units form a first photoelectric conversion group, and the plurality of first photoelectric conversion units included in the first photoelectric conversion group share one floating diffusion part. In one of the plurality of first photoelectric conversion units and the surrounding area thereof, a first high density region having a higher density than the remaining first photoelectric conversion units of the plurality of first photoelectric conversion units in terms of the sum of a wiring area and a transistor area, is present. In the second substrate, at least one of the plurality of second photoelectric conversion units is disposed so as to correspond to the first photoelectric conversion group. The plurality of second photoelectric conversion units are present under a region other than the first high density region.

Description

固体撮像装置Solid-state imaging device
　本発明は、固体撮像装置、より詳しくは、可視光画像と赤外光画像を同時に取得する撮像装置に関する。 The present invention relates to a solid-state imaging device, and more particularly, to an imaging device that simultaneously acquires a visible light image and an infrared light image.
　近年、蛍光観察用内視鏡システムや静脈認証システム等に用いるために、可視光観察と共に赤外光観察を行なう撮像装置や撮像システムが盛んになっており、可視光観察では視認が難しい被写体からの情報を得ている。このため、可視光画像と赤外光画像同時に取得することが可能な撮像装置が広く提案されている（例えば、特許文献１参照）。 In recent years, imaging devices and systems that perform infrared light observation together with visible light observation have become popular for use in endoscope systems for fluorescence observation, vein authentication systems, and the like. The information has been obtained. For this reason, an imaging device capable of simultaneously acquiring a visible light image and an infrared light image has been widely proposed (for example, see Patent Document 1).
　図１は、このような撮像装置の断面図である。撮像装置１００は、第１の基板１０１と、第２の基板１０２と、カラーフィルタ１０３と、接続部１０４とを備えている。第１の基板１０１と第２の基板１０２は、それぞれ複数の画素を備えており、受光した光量に応じた画素信号を出力する。第１の基板の受光面側（図の上側）には、ＲＧＢのカラーフィルタ１０３が形成されている。 FIG. 1 is a cross-sectional view of such an imaging device. The imaging device 100 includes a first substrate 101, a second substrate 102, a color filter 103, and a connection unit 104. Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and outputs a pixel signal corresponding to the amount of received light. RGB color filters 103 are formed on the light receiving surface side (upper side in the figure) of the first substrate.
　第１の基板１０１は裏面照射型（ＢＳＩ型）の撮像基板であり、第１の基板１０１の厚さは数ｕｍ程度と薄い。そのために、第１の基板１０１の受光面側から入射した光の一部は透過し、第２の基板１０２の受光面側に入射する。なお、波長が短い光に対するシリコンの光吸収率は高く、波長が長い光に対するシリコンの光吸収率は低い。そのため、厚さが薄い第１の基板１０１では、波長の長い赤外光の一部が吸収されずに透過し、第２の基板１０２に入射する。従って、第１の基板１０１では可視光を検出し、第２の基板１０２では赤外光を検出することができる。このように、第１の基板１０１と第２の基板１０２を用いて、可視光画像と赤外光画像を同時に観察することができる。 (1) The first substrate 101 is a back-illuminated (BSI) imaging substrate, and the thickness of the first substrate 101 is as thin as about several μm. Therefore, part of the light incident from the light receiving surface side of the first substrate 101 is transmitted, and is incident on the light receiving surface side of the second substrate 102. Note that silicon has a high light absorptivity for light having a short wavelength, and a low light absorptivity of silicon for light having a long wavelength. Therefore, in the first substrate 101 having a small thickness, part of infrared light having a long wavelength is transmitted without being absorbed, and is incident on the second substrate 102. Therefore, the first substrate 101 can detect visible light, and the second substrate 102 can detect infrared light. As described above, the visible light image and the infrared light image can be simultaneously observed using the first substrate 101 and the second substrate 102.
　図１６は、従来技術に係る撮像装置の断面の詳細を示す図である。第１の基板１０１と第２の基板１０２はそれぞれ複数の画素を備えており、各画素は光電変換層と配線層とから構成されている。第１の基板１０１は、第１の光電変換層１１１と第１の配線層１２１とから構成されている。第２の基板１０２は、第２の光電変換層１１２と第２の配線層１２２とから構成されている。 FIG. 16 is a diagram showing details of a cross section of an imaging device according to the related art. Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and each pixel includes a photoelectric conversion layer and a wiring layer. The first substrate 101 includes a first photoelectric conversion layer 111 and a first wiring layer 121. The second substrate 102 includes a second photoelectric conversion layer 112 and a second wiring layer 122.
　光電変換層には光電変換部（フォトダイオード）が形成されており、ＲＧＢのカラーフィルタ１０３を透過した光を受光し、光電変換する。第１の光電変換層１１１には第１の光電変換部１１３が形成されている。第２の光電変換層１１２には第２の光電変換部１１４が形成されている。 光電 A photoelectric conversion unit (photodiode) is formed in the photoelectric conversion layer, and receives light transmitted through the RGB color filter 103 and performs photoelectric conversion. A first photoelectric conversion unit 113 is formed in the first photoelectric conversion layer 111. On the second photoelectric conversion layer 112, a second photoelectric conversion unit 114 is formed.
　配線層は複数の配線１２３から構成された層が積み重なっており、各層は層間絶縁膜１２４により絶縁されている。配線１２３とＭＯＳトランジスタ１１５は、各画素を駆動させるための制御線や各画素の信号を読み出すための回路を含む。 (4) The wiring layer is formed by stacking layers composed of a plurality of wirings 123, and each layer is insulated by an interlayer insulating film 124. The wiring 123 and the MOS transistor 115 include a control line for driving each pixel and a circuit for reading a signal of each pixel.
特開２０１４－１３５５３５号公報JP 2014-135535 A
　図１６において、第１の光電変換層１１１で吸収されずに透過した光は、第２の基板１０２における第２の光電変換層１１２に入射する前に、第１の基板１０１における第１の配線層１２１を構成する配線および第２の基板１０２における第２の配線層１２２を構成する配線に当たって反射する。そのために、第２の光電変換層１１２に入射する光量が減少してしまい、第２の光電変換部１１４の感度が低下する。 In FIG. 16, light transmitted through the first photoelectric conversion layer 111 without being absorbed is incident on the first wiring of the first substrate 101 before being incident on the second photoelectric conversion layer 112 of the second substrate 102. The light is reflected on the wiring forming the layer 121 and the wiring forming the second wiring layer 122 in the second substrate 102. Therefore, the amount of light incident on the second photoelectric conversion layer 112 decreases, and the sensitivity of the second photoelectric conversion unit 114 decreases.
　更に、画素の微細化が進むにつれて、各画素における配線の占める割合が増加し、各画素の開口率が低下する。そのため、第２の光電変換層１１２に入射する光量は更に減少し、第２の光電変換部１１４の感度は更に低下する。 Furthermore, as pixels become finer, the ratio of wiring in each pixel increases, and the aperture ratio of each pixel decreases. Therefore, the amount of light incident on the second photoelectric conversion layer 112 further decreases, and the sensitivity of the second photoelectric conversion unit 114 further decreases.
　上述の事情を鑑み、本発明は、可視光と赤外光を同時に検出する積層型イメージャ（撮像装置）において、第２の光電変換層（下側のフォトダイオード）に入射する光量の低下を抑制するための画素構造を提供することを目的とする。 In view of the above circumstances, the present invention suppresses a decrease in the amount of light incident on a second photoelectric conversion layer (lower photodiode) in a stacked imager (imaging device) that simultaneously detects visible light and infrared light. It is an object of the present invention to provide a pixel structure for performing the above.
　本発明の第一の態様は、複数の第１の光電変換部を有する第１の基板と、前記第１の基板に積層して設けられ、複数の第２の光電変換部を有する第２の基板と、を備える固体撮像装置であって、前記第１の基板において、前記複数の第１の光電変換部のうち少なくとも２つの第１の光電変換部が第１の光電変換グループを形成し、前記第１の光電変換グループに含まれる複数の第１の光電変換部で１つのフローティングディフュージョン部を共有し、前記複数の第１の光電変換部のうち１つの第１の光電変換部とこの周囲において、配線とトランジスタの面積の和が、前記複数の第１の光電変換部のうち残りの第１の光電変換部よりも高密度で存在する第１の高密度領域が存在し、前記第２の基板において、前記複数の第２の光電変換部は、前記第１の光電変換グループに対応して少なくとも１つ設けられ、前記第１の高密度領域でない領域の下に、前記複数の第２の光電変換部が存在することを特徴とする固体撮像装置である。 According to a first aspect of the present invention, a first substrate having a plurality of first photoelectric conversion units and a second substrate having a plurality of second photoelectric conversion units are provided so as to be stacked on the first substrate. A solid-state imaging device comprising: a substrate; and wherein in the first substrate, at least two first photoelectric conversion units among the plurality of first photoelectric conversion units form a first photoelectric conversion group; A plurality of first photoelectric conversion units included in the first photoelectric conversion group share one floating diffusion unit, and one of the plurality of first photoelectric conversion units and one of the first photoelectric conversion units and its surroundings Wherein there is a first high-density region in which the sum of the area of the wiring and the area of the transistor is higher than that of the remaining first photoelectric conversion units among the plurality of first photoelectric conversion units; Wherein the plurality of second photoelectric conversion units are A solid-state imaging device, wherein at least one second photoelectric conversion unit is provided corresponding to the first photoelectric conversion group, and the plurality of second photoelectric conversion units exist below a region other than the first high-density region. It is.
　前記第２の基板において、前記複数の第２の光電変換部のうち少なくとも２つの第２の光電変換部が第２の光電変換グループを形成し、前記第２の光電変換グループに含まれる複数の第２の光電変換部で１つのフローティングディフュージョン部を共有し、前記複数の第２の光電変換部のうち１つの第２の光電変換部とこの周囲において、配線とトランジスタの面積の和が前記複数の第２の光電変換部のうち残りの第２の光電変換部よりも高密度で存在する第２の高密度領域が、前記第１の高密度領域と同じ位置にあってもよい。 In the second substrate, at least two second photoelectric conversion units among the plurality of second photoelectric conversion units form a second photoelectric conversion group, and a plurality of second photoelectric conversion groups included in the second photoelectric conversion group are included. One floating diffusion portion is shared by the second photoelectric conversion portions, and the sum of the area of the wiring and the transistor is one of the plurality of second photoelectric conversion portions in and around the second photoelectric conversion portion. The second high-density region of the second photoelectric conversion unit having a higher density than the remaining second photoelectric conversion unit may be located at the same position as the first high-density region.
　前記第１の高密度領域は、少なくとも増幅トランジスタを含んでもよい。 (4) The first high-density region may include at least an amplification transistor.
　前記第２の高密度領域は、少なくとも増幅トランジスタを含んでもよい。 The second high-density region may include at least an amplification transistor.
　前記第１の基板の上に配置され、可視領域と赤外領域に透過帯域を有するカラーフィルタをさらに備え、前記複数の第１の光電変換部は、前記カラーフィルタを透過した光の露光量に応じた第１の信号電荷を出力し、複数の前記第２の光電変換部は、少なくとも赤外領域に感度を有し、前記第１の基板を透過した光の露光量に応じた第２の信号電荷を出力してもよい。 A color filter that is disposed on the first substrate and has a transmission band in a visible region and an infrared region, wherein the plurality of first photoelectric conversion units are configured to reduce an exposure amount of light transmitted through the color filter. Outputs a first signal charge corresponding to the second signal, and the plurality of second photoelectric conversion units have sensitivity in at least an infrared region, and output a second signal charge corresponding to an exposure amount of light transmitted through the first substrate. The signal charge may be output.
　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、前記第１の高密度領域は、前記Ｒフィルタの直下の前記第１の光電変換部の面位置に設けられてもよい。 The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region, wherein the first high-density region includes the R filter. May be provided at a surface position of the first photoelectric conversion unit immediately below the first photoelectric conversion unit.
　前記第１の基板の第１の配線層と、前記第２の基板の第２の配線層は向かい合わせて設けられ、前記第１の基板において、前記第１の配線層内の配線は前記第１の高密度領域内に配置され、前記第２の基板において、前記第２の配線層内の配線は前記第２の高密度領域内に配置されてもよい。 The first wiring layer of the first substrate and the second wiring layer of the second substrate are provided so as to face each other, and in the first substrate, the wiring in the first wiring layer is The second wiring board may be arranged in the second high-density region, and the wiring in the second wiring layer may be arranged in the second high-density region in the second substrate.
　前記第１の基板の第１の配線層は前記第１の光電変換部の下に設けられ、前記第２の基板の第２の配線層は、前記第２の光電変換部の下に設けられ、前記第１の基板において、前記第１の配線層内の配線は前記第１の高密度領域内に配置されてもよい。 A first wiring layer of the first substrate is provided below the first photoelectric conversion unit, and a second wiring layer of the second substrate is provided below the second photoelectric conversion unit. In the first substrate, the wiring in the first wiring layer may be arranged in the first high-density region.
　前記第１の基板と前記第２の基板との間に、可視光をカットし赤外光を透過するフィルタが設けられてもよい。 フ ィ ル タ A filter that cuts visible light and transmits infrared light may be provided between the first substrate and the second substrate.
　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、前記第１の光電変換部は、前記カラーフィルタの下の第１の光電変換層内に配置され、前記Ｂフィルタが配置される領域の第１の前記光電変換層の厚みおよび前記Ｇフィルタが配置される領域の前記第１の光電変換層の厚みよりも、前記Ｒフィルタが配置される領域の前記第１の光電変換層の厚みが厚くてもよい。 The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region. The first photoelectric conversion unit includes the color filter. And a thickness of the first photoelectric conversion layer in a region where the B filter is disposed and a thickness of the first photoelectric conversion layer in a region where the G filter is disposed. The thickness of the first photoelectric conversion layer in a region where the R filter is arranged may be thicker than the thickness.
　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、前記第２の光電変換部は、第２の光電変換層内に配置され、前記第２の光電変換層において、前記Ｒフィルタに対応する前記第２の光電変換部が存在しなくてもよい。 The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region. The second photoelectric conversion unit includes a second photoelectric conversion unit. The second photoelectric conversion unit corresponding to the R filter may not be present in the second photoelectric conversion layer, which is disposed in a photoelectric conversion layer.
　本発明の各態様によれば、可視光と赤外光を同時に検出する積層型イメージャ（撮像装置）において、第２の光電変換層（下側のフォトダイオード）に入射する光量の低下を抑制するための画素構造を提供することができる。 According to each aspect of the present invention, in a stacked imager (imaging device) that simultaneously detects visible light and infrared light, a decrease in the amount of light incident on the second photoelectric conversion layer (lower photodiode) is suppressed. Pixel structure can be provided.
本発明の実施形態における撮像装置の断面を示した断面図である。FIG. 2 is a cross-sectional view illustrating a cross section of the imaging device according to the embodiment of the present invention. 本発明の実施形態において、カラーフィルタが形成された第１の基板に含まれる画素の配列を示した概略図である。FIG. 2 is a schematic diagram illustrating an arrangement of pixels included in a first substrate on which a color filter is formed in an embodiment of the present invention. 本発明の実施形態において、第２の基板に含まれる画素の配列を示した概略図である。FIG. 3 is a schematic diagram illustrating an arrangement of pixels included in a second substrate in the embodiment of the present invention. 本発明の実施形態において、第１の基板に含まれる１組の単位画素領域の画素と、第２の基板に含まれる画素との配置関係を示した概略図である。FIG. 4 is a schematic diagram illustrating an arrangement relationship between pixels in a set of unit pixel regions included in a first substrate and pixels included in a second substrate in the embodiment of the present invention. 本発明の実施形態におけるカラーフィルタの透過特性を示したグラフである。5 is a graph illustrating transmission characteristics of a color filter according to the embodiment of the present invention. 本発明の第１実施形態に係る撮像装置のイメージ図である。It is an image figure of the imaging device concerning a 1st embodiment of the present invention. 本発明の第１実施形態に係る撮像装置の断面の詳細を示す図である。It is a figure showing the detail of the section of the imaging device concerning a 1st embodiment of the present invention. 本発明の第１実施形態に係る撮像装置の単位画素領域における画素部に関する回路構成を示す図である。FIG. 2 is a diagram illustrating a circuit configuration related to a pixel unit in a unit pixel region of the imaging device according to the first embodiment of the present invention. 本発明の第１実施形態に係る撮像装置の単位画素領減のカラーフィルタの配置図を示す図である。FIG. 2 is a diagram illustrating an arrangement diagram of a color filter having a unit pixel area reduction of the imaging device according to the first embodiment of the present invention. 本発明の第１実施形態に係る撮像装置の単位画素領域の画素レイアウトを示す図である。FIG. 2 is a diagram illustrating a pixel layout of a unit pixel region of the imaging device according to the first embodiment of the present invention. 本発明の第１実施形態の変形例１に係る撮像装置の断面の詳細を示す図である。FIG. 6 is a diagram illustrating details of a cross section of the imaging device according to Modification Example 1 of the first embodiment of the present invention. 本発明の第１実施形態の変形例２に係る撮像装置の断面の詳細を示す図である。It is a figure showing the detail of the section of the imaging device concerning modification 2 of a 1st embodiment of the present invention. 本発明の第２実施形態に係る撮像装置の断面の詳細を示す図である。It is a figure showing the detail of the section of the imaging device concerning a 2nd embodiment of the present invention. ＲＧＢ画素の分光感度の一例を示す図である。FIG. 3 is a diagram illustrating an example of spectral sensitivity of RGB pixels. ４５０ｎｍ、５３０ｎｍ、６２０ｎｍ、および８００ｎｍの光がＳｉ内を任意の距離進んだ場合の光量をプロットしたグラフである。It is the graph which plotted the light quantity at the time of 450 nm, 530 nm, 620 nm, and 800 nm light having traveled arbitrary distance in Si. 従来技術に係る撮像装置の断面の詳細を示す図である。FIG. 11 is a diagram illustrating details of a cross section of an imaging device according to a conventional technique.
　以下、本発明の実施形態について図面を参照して説明する。なお、図１～図５は、従来技術と同様であるが、本発明の理解を助けるために以下説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 are the same as those in the related art, but will be described below to help understand the present invention.
　図１は、本発明の実施形態における撮像装置１００（固体撮像装置）の断面を示した断面図である。図示する例では、撮像装置１００は、第１の基板１０１と、第２の基板１０２と、カラーフィルタ１０３（第１のフィルタ）と、接続部１０４とを備えている。第１の基板１０１と第２の基板１０２は、それぞれシリコンチップ上に形成されており複数の画素を備えている。第１の基板１０１の受光面側には、ＲＧＢのカラーフィルタ１０３が設けられている。カラーフィルタ１０３の配置およびカラーフィルタ１０３が透過する光の波長については後述する。 FIG. 1 is a cross-sectional view showing a cross section of an imaging device 100 (solid-state imaging device) according to an embodiment of the present invention. In the illustrated example, the imaging device 100 includes a first substrate 101, a second substrate 102, a color filter 103 (first filter), and a connection unit 104. Each of the first substrate 101 and the second substrate 102 is formed on a silicon chip and has a plurality of pixels. An RGB color filter 103 is provided on the light receiving surface side of the first substrate 101. The arrangement of the color filters 103 and the wavelength of light transmitted by the color filters 103 will be described later.
　カラーフィルタ１０３は可視領域と赤外領域に透過帯域を有する。カラーフィルタ１０３は有機材料（顔料）により生成されており、赤色のカラーフィルタ（Ｒフィルタ）は、赤色の可視光と赤外光を透過し、緑色のカラーフィルタ（Ｇフィルタ）は緑色の可視光と赤外光を透過し、青色のカラーフィルタ（Ｂフィルタ）は青色の可視光と赤外光を透過する特性を持つ。 The color filter 103 has transmission bands in the visible region and the infrared region. The color filter 103 is made of an organic material (pigment), the red color filter (R filter) transmits red visible light and infrared light, and the green color filter (G filter) is green visible light. And a blue color filter (B filter) have a characteristic of transmitting blue visible light and infrared light.
　また、第１の基板１０１と第２の基板１０２とは段積み（スタック）されている。図示する例では、第１の基板１０１の受光面とは反対側に、第２の基板１０２が配置されている。第２の基板１０２の受光面は、第１の基板１０１が存在する側である。また、第１の基板１０１と第２の基板１０２との間には接続部１０４が構成されており、第１の基板１０１と第２の基板１０２は接続部１０４を介して電気的に接続されている。すなわち、第１の基板１０１と第２の基板１０２とは接続部１０４を介して貼り合わせている。 {Circle around (1)} The first substrate 101 and the second substrate 102 are stacked. In the illustrated example, the second substrate 102 is disposed on the side opposite to the light receiving surface of the first substrate 101. The light receiving surface of the second substrate 102 is on the side where the first substrate 101 exists. Further, a connection portion 104 is formed between the first substrate 101 and the second substrate 102, and the first substrate 101 and the second substrate 102 are electrically connected to each other through the connection portion 104. ing. That is, the first substrate 101 and the second substrate 102 are bonded to each other via the connection portion 104.
　ここで、第１の基板１０１は裏面照射型の撮像基板であり、第１の基板１０１の厚さは数ｕｍ程度と薄い。そのために、第１の基板１０１の受光面側から入射した光の一部は透過し、第２の基板１０２の受光面側に入射する。なお、シリコンの光吸収率は波長によって異なる。波長が短い光に対するシリコンの光吸収率は高く、波長が長い光に対するシリコンの光吸収率は低い。すなわち、厚さが約３ｕｍの薄い第１の基板１０１では、撮像装置１００に入射した光のうち、波長が短い可視光はほとんど吸収されるが、波長が長い赤外光は一部吸収されずに、第１の基板を透過する。従って、第２の基板１０２には、赤外光が入射する。第２の基板１０２は、表面照射型の撮像基板であり、第１の基板１０１よりも厚い。第２の基板１０２では、第１の基板１０１を透過した赤外光を検出する。なお、第１の基板１０１は、裏面照射型の撮像基板に限らず、可視光を吸収し、赤外光を透過する基板であればどのような基板でもよい。 Here, the first substrate 101 is a back-illuminated imaging substrate, and the thickness of the first substrate 101 is as thin as about several μm. Therefore, part of the light incident from the light receiving surface side of the first substrate 101 is transmitted, and is incident on the light receiving surface side of the second substrate 102. Note that the light absorption of silicon differs depending on the wavelength. The light absorptivity of silicon for light with a short wavelength is high, and the light absorptivity of silicon for light with a long wavelength is low. That is, in the thin first substrate 101 having a thickness of about 3 μm, of light incident on the imaging device 100, visible light having a short wavelength is almost absorbed, but infrared light having a long wavelength is not partially absorbed. Through the first substrate. Therefore, infrared light is incident on the second substrate 102. The second substrate 102 is a front-illuminated imaging substrate and is thicker than the first substrate 101. The second substrate 102 detects infrared light transmitted through the first substrate 101. Note that the first substrate 101 is not limited to a back-illuminated imaging substrate, and may be any substrate that absorbs visible light and transmits infrared light.
　図２は、本発明の実施形態において、カラーフィルタ１０３が設けられた第１の基板１０１に含まれる画素の配列を示した概略図である。図示する例では、４行８列の二次元状に配列された計３２個の画素の例を示している。なお、第１の基板１０１に含まれる画素の数および配列は図示する例に限らず、どのような数および配列でもよい。 FIG. 2 is a schematic diagram showing an arrangement of pixels included in the first substrate 101 provided with the color filters 103 in the embodiment of the present invention. In the illustrated example, an example is shown in which a total of 32 pixels are arranged two-dimensionally in 4 rows and 8 columns. The number and arrangement of the pixels included in the first substrate 101 are not limited to the illustrated example, but may be any number and arrangement.
　本発明の実施形態では、カラーフィルタ１０３の配列はベイヤー配列であり、縦と横に隣接する４つの画素を１組の単位画素領域２００とする。そのため、図示する通り、１組の単位画素領域２００には、赤色と赤外光の波長領域を透過するカラーフィルタ１０３が設けられた１つの画素２０１と、緑色と赤外光の波長領域を透過するカラーフィルタ１０３が設けられた２つの画素２０２と、青色と赤外光の波長領域を透過するカラーフィルタ１０３が設けられた１つの画素２０３とで構成されている。 In the embodiment of the present invention, the color filters 103 are arranged in a Bayer array, and four pixels vertically and horizontally adjacent to each other are defined as a set of unit pixel areas 200. Therefore, as shown in the figure, one set of unit pixel regions 200 has one pixel 201 provided with a color filter 103 that transmits red and infrared light wavelength regions, and transmits one green pixel and infrared light wavelength region. And a pixel 203 provided with a color filter 103 that transmits the wavelength region of blue and infrared light.
　第１の基板１０１に含まれる各画素２０１～２０３は、それぞれ光電変換素子（第１の光電変換素子）および信号読み出し回路を備えている。各光電変換素子は、露光量に応じた第１の信号電荷を読み出し回路に出力する。信号読み出し回路は、光電変換素子が出力した第１の信号電荷を第１の電気信号として出力する。 Each of the pixels 201 to 203 included in the first substrate 101 includes a photoelectric conversion element (first photoelectric conversion element) and a signal readout circuit. Each photoelectric conversion element outputs a first signal charge corresponding to an exposure amount to a readout circuit. The signal readout circuit outputs the first signal charge output from the photoelectric conversion element as a first electric signal.
　図３は、本発明の実施形態において、第２の基板１０２に含まれる画素の配列を示した概略図である。図示する例では、４行８列の二次元状に配列された計３２個の画素の例を示している。なお、第２の基板１０２に含まれる画素の数および配列は図示する例に限らず、どのような数および配列でもよい。 FIG. 3 is a schematic diagram showing an arrangement of pixels included in the second substrate 102 in the embodiment of the present invention. In the illustrated example, an example is shown in which a total of 32 pixels are arranged two-dimensionally in 4 rows and 8 columns. The number and arrangement of the pixels included in the second substrate 102 are not limited to the illustrated example, but may be any number and arrangement.
　第２の基板１０２に含まれる各画素３０１～３０３は、それぞれ光電変換素子（第２の光電変換素子）および信号読み出し回路を備えている。各光電変換素子は、露光量に応じた第２の信号電荷を読み出し回路に出力する。信号読み出し回路は、光電変換素子が出力した第２の信号電荷を第２の電気信号として出力する。 Each of the pixels 301 to 303 included in the second substrate 102 includes a photoelectric conversion element (second photoelectric conversion element) and a signal readout circuit. Each photoelectric conversion element outputs a second signal charge corresponding to the exposure amount to the readout circuit. The signal readout circuit outputs the second signal charge output from the photoelectric conversion element as a second electric signal.
　図４は、本発明の実施形態において、第１の基板１０１に含まれる１組の単位画素領域２００の画素２０１～２０３と、第２の基板１０２に含まれる画素３０１～３０３との配置関係を示した概略図である。図示する例では、赤色の光と赤外光とを透過するカラーフィルタ１０３が設けられた画素２０１を透過した赤外光が入射する位置に、画素３０１は配置されている。また、緑色の光と赤外光とを透過するカラーフィルタ１０３が設けられた画素２０２を透過した赤外光が入射する位置に、画素３０２は配置されている。また、青色の光と赤外光とを透過するカラーフィルタ１０３が設けられた画素２０３を透過した赤外光が入射する位置に、画素３０３は配置されている。すなわち、第１の基板１０１に含まれる画素２０１～２０３と、第２の基板１０２に含まれる画素３０１～３０３とは１対１で対応している。 FIG. 4 shows an arrangement relationship between pixels 201 to 203 of a set of unit pixel regions 200 included in the first substrate 101 and pixels 301 to 303 included in the second substrate 102 in the embodiment of the present invention. FIG. In the illustrated example, the pixel 301 is disposed at a position where the infrared light transmitted through the pixel 201 provided with the color filter 103 transmitting red light and infrared light is incident. The pixel 302 is arranged at a position where the infrared light transmitted through the pixel 202 provided with the color filter 103 transmitting the green light and the infrared light is incident. Further, the pixel 303 is disposed at a position where the infrared light transmitted through the pixel 203 provided with the color filter 103 transmitting blue light and infrared light is incident. That is, the pixels 201 to 203 included in the first substrate 101 and the pixels 301 to 303 included in the second substrate 102 have a one-to-one correspondence.
　次に、カラーフィルタ１０３が透過する光の波長について説明する。図５は、本発明の実施形態におけるカラーフィルタ１０３の透過特性を示したグラフである。図示するグラフの横軸は波長を示し、縦軸は各波長におけるカラーフィルタ１０３の透過率を示している。図示する例では、線５１１は、青色の光と赤外光とを透過する青色のカラーフィルタ１０３が、約４００ｎｍ～５００ｎｍの波長の光（青色の光）と、約７００ｎｍ以上の波長の光（赤外光）とを透過することを示している。また、線５１２は、緑色の光と赤外光とを透過する緑色のカラーフィルタ１０３が、約５００ｎｍ～６００ｎｍの波長の光（緑色の光）と、約７００ｎｍ以上の波長の光（赤外光）とを透過することを示している。また、線５１３は、赤色の光と赤外光とを透過する緑色のカラーフィルタ１０３が、約６００ｎｍ以上の波長の光（赤色の光および赤外光）を透過することを示している。 Next, the wavelength of light transmitted by the color filter 103 will be described. FIG. 5 is a graph showing the transmission characteristics of the color filter 103 according to the embodiment of the present invention. The horizontal axis of the graph shown in the drawing represents the wavelength, and the vertical axis represents the transmittance of the color filter 103 at each wavelength. In the illustrated example, the line 511 indicates that the blue color filter 103 transmitting the blue light and the infrared light has a wavelength of about 400 nm to 500 nm (blue light) and a wavelength of about 700 nm or more (blue). Infrared light). The line 512 indicates that the green color filter 103 transmitting the green light and the infrared light has a wavelength of about 500 nm to 600 nm (green light) and a wavelength of about 700 nm or more (infrared light). ). A line 513 indicates that the green color filter 103 transmitting red light and infrared light transmits light having a wavelength of about 600 nm or more (red light and infrared light).
　次に撮像装置１００の動作について説明する。なお、本発明の実施形態では、光源は可視領域から赤外領域までの波長を含んだ照明光を用いる。そして、生体組織や指などの対象物に照明光を照射し、その透過光または反射光を、撮像装置１００に入射させる。 Next, the operation of the imaging device 100 will be described. In the embodiment of the present invention, the light source uses illumination light including wavelengths from a visible region to an infrared region. Then, an illuminating light is applied to a target object such as a living tissue or a finger, and the transmitted light or the reflected light is incident on the imaging device 100.
　カラーフィルタ１０３が設けられた第１の基板１０１の受光面側に光が入射される。図５に示す透過特性のように、赤色のカラーフィルタ１０３は赤色の光と赤外光とを透過する。また、緑色のカラーフィルタ１０３は、緑色の光と赤外光とを透過する。また、青色のカラーフィルタ１０３は、青色の光と赤外光とを透過する。 Light is incident on the light receiving surface side of the first substrate 101 on which the color filter 103 is provided. Like the transmission characteristics shown in FIG. 5, the red color filter 103 transmits red light and infrared light. The green color filter 103 transmits green light and infrared light. Further, the blue color filter 103 transmits blue light and infrared light.
　第１の基板１０１の各画素２０１～２０３は、それぞれのカラーフィルタ１０３を透過した可視光を検出し、第１の電気信号を出力する。具体的には、赤色のカラーフィルタ１０３が設けられた画素２０１は、赤色の光に応じた第１の電気信号を出力する。また、緑色のカラーフィルタ１０３が設けられた画素２０２は、緑色の光に応じた第１の電気信号を出力する。また、青色のカラーフィルタ１０３が設けられた画素２０３は、青色の光に応じた第１の電気信号を出力する。図示せぬ処理部は、各画素２０１～２０３が出力した第１の電気信号に基づいて可視光画像を生成する。
　なお、厳密には、第１の基板１０１では、可視光以外に、赤外光も吸収される。そのため、第１の基板１０１から出力される第１の電気信号には、可視光成分以外に、わずかながらに検出される赤外光成分も含まれてしまう。ただし、本実施形態で考える赤外光は蛍光などの微弱光であり、基板には、可視光に比べて弱い光が入射する。そのため、第１の信号において、可視光によって生成される信号の方が、赤外光によって生成される信号に比べて支配的である。そこで、本明細書では、第１の基板１０１の各画素は可視光を検出するという記述としている。 Each of the pixels 201 to 203 of the first substrate 101 detects visible light transmitted through each of the color filters 103 and outputs a first electric signal. Specifically, the pixel 201 provided with the red color filter 103 outputs a first electric signal corresponding to red light. The pixel 202 provided with the green color filter 103 outputs a first electric signal corresponding to green light. The pixel 203 provided with the blue color filter 103 outputs a first electric signal corresponding to blue light. A processing unit (not shown) generates a visible light image based on the first electric signal output from each of the pixels 201 to 203.
Strictly speaking, the first substrate 101 absorbs not only visible light but also infrared light. Therefore, the first electric signal output from the first substrate 101 includes, in addition to the visible light component, a slightly detected infrared light component. However, the infrared light considered in the present embodiment is weak light such as fluorescence, and light that is weaker than visible light enters the substrate. Therefore, in the first signal, a signal generated by visible light is more dominant than a signal generated by infrared light. Therefore, in this specification, description is made such that each pixel of the first substrate 101 detects visible light.
　第２の基板１０２には、第１の基板１０１を透過した赤外光が入射される。第２の基板１０２が備えている各画素３０１～３０３は、少なくとも赤外領域に感度を有する。第２の基板１０２の各画素３０１～３０３は、赤外光の波長の光に応じた第２の電気信号を出力する。図示せぬ処理部は、各画素３０１～３０３が出力した第２の電気信号に基づいて赤外光画像を生成する。 (4) The infrared light transmitted through the first substrate 101 is incident on the second substrate 102. Each of the pixels 301 to 303 included in the second substrate 102 has sensitivity at least in the infrared region. Each of the pixels 301 to 303 of the second substrate 102 outputs a second electric signal according to light having a wavelength of infrared light. A processing unit (not shown) generates an infrared light image based on the second electric signal output from each of the pixels 301 to 303.
　上述したとおり、本発明の実施形態によれば、第１の基板１０１と第２の基板１０２とは段積みされている。また、第１の基板１０１は赤外光を透過する。これにより、第１の基板１０１が備えている画素２０１～２０３は、可視光に基づいた第１の電気信号を出力することができる。また、第２の基板１０２が備えている画素３０１～３０３は、赤外光に基づいた第２の電気信号を出力することができる。また、第１の電気信号より、可視光画像を生成することができ、第２の電気信号より、赤外光画像を生成することができる。 As described above, according to the embodiment of the present invention, the first substrate 101 and the second substrate 102 are stacked. Further, the first substrate 101 transmits infrared light. Accordingly, the pixels 201 to 203 included in the first substrate 101 can output the first electric signal based on the visible light. Further, the pixels 301 to 303 included in the second substrate 102 can output a second electric signal based on infrared light. Further, a visible light image can be generated from the first electric signal, and an infrared light image can be generated from the second electric signal.
　また、本発明の実施形態では、光源として可視領域から赤外領域を含んだ光を用いるために、可視光と赤外光の時間的な切替えは必要ない。そのために、撮像装置１００は、可視光画像を生成することができる第１の電気信号と、赤外光画像を生成することができる第２の電気信号とを同時に出力することができる。また、本発明の実施形態における撮像装置１００は、ダイクロイックミラーや複数のレンズ、および可視光検出用と赤外光検出用の撮像装置を必要としない。そのために、装置の小型化や低コスト化を実現することができる。従って、本発明の実施形態によれば、撮像装置１００は、安価で、可視光画像と赤外光画像を同時に取得することができる。 In addition, in the embodiment of the present invention, since light including a visible region to an infrared region is used as a light source, there is no need to temporally switch between visible light and infrared light. Therefore, the imaging device 100 can simultaneously output a first electric signal capable of generating a visible light image and a second electric signal capable of generating an infrared light image. Further, the imaging device 100 according to the embodiment of the present invention does not require a dichroic mirror, a plurality of lenses, and imaging devices for detecting visible light and detecting infrared light. Therefore, size reduction and cost reduction of the device can be realized. Therefore, according to the embodiment of the present invention, the imaging device 100 can simultaneously acquire the visible light image and the infrared light image at low cost.
　次に、本発明の特徴である、可視光と赤外光を同時に検出する積層型の撮像装置において、第２の光電変換層（下側のフォトダイオード）に入射する光量の低下を抑制するための画素構造について説明する。 Next, in the stacked imaging device that simultaneously detects visible light and infrared light, which is a feature of the present invention, in order to suppress a decrease in the amount of light incident on the second photoelectric conversion layer (lower photodiode). Will be described.
　（第１実施形態）
　図６は、本発明の第１実施形態に係る撮像装置のイメージ図である。撮像装置１００において、図の上側（第１の基板の受光面側）から順に、カラーフィルタ１０３、第１の基板１０１、第２の基板１０２の各層が配置される。各層において、複数の画素（本実施形態では２×２画素の４画素）から単位画素領域２００が構成され、単位画素領域の繰り返しにより光電変換層の全体が構成される。 (1st Embodiment)
FIG. 6 is an image diagram of the imaging device according to the first embodiment of the present invention. In the imaging device 100, the layers of the color filter 103, the first substrate 101, and the second substrate 102 are arranged in order from the upper side of the drawing (the light receiving surface side of the first substrate). In each layer, a unit pixel region 200 is configured from a plurality of pixels (four pixels of 2 × 2 pixels in the present embodiment), and the entire photoelectric conversion layer is configured by repeating the unit pixel region.
　図７は、本発明の第１実施形態に係る撮像装置の断面の詳細を示す図である。第１の基板１０１と第２の基板１０２はそれぞれ複数の画素を備えており、各画素は光電変換層と配線層とから構成されている。第１の基板１０１は、第１の光電変換層１１１と第１の配線層１２１とから構成されている。第２の基板１０２は、第２の光電変換層１１２と第２の配線層１２２とから構成されている。 FIG. 7 is a diagram showing details of a cross section of the imaging device according to the first embodiment of the present invention. Each of the first substrate 101 and the second substrate 102 includes a plurality of pixels, and each pixel includes a photoelectric conversion layer and a wiring layer. The first substrate 101 includes a first photoelectric conversion layer 111 and a first wiring layer 121. The second substrate 102 includes a second photoelectric conversion layer 112 and a second wiring layer 122.
　光電変換層には光電変換部（フォトダイオード）が形成されており、ＲＧＢのカラーフィルタ１０３を透過した光を受光し、光電変換する。第１の光電変換層１１１には第１の光電変換部１１３が形成されている。第２の光電変換層１１２には第２の光電変換部１１４が形成されている。 光電 A photoelectric conversion unit (photodiode) is formed in the photoelectric conversion layer, and receives light transmitted through the RGB color filter 103 and performs photoelectric conversion. A first photoelectric conversion unit 113 is formed in the first photoelectric conversion layer 111. On the second photoelectric conversion layer 112, a second photoelectric conversion unit 114 is formed.
　配線層は複数の配線１２３から構成された層が積み重なっており、各層は層間絶縁膜１２４により絶縁されている。配線１２３とＭＯＳトランジスタ１１５は、各画素を駆動させるための制御線や各画素の信号を読み出すための回路を含む。 (4) The wiring layer is formed by stacking layers composed of a plurality of wirings 123, and each layer is insulated by an interlayer insulating film 124. The wiring 123 and the MOS transistor 115 include a control line for driving each pixel and a circuit for reading a signal of each pixel.
　本実施形態では、図７に示すように、単位画素領域のうち１つの画素（本実施形態ではＲ画素）の下側に、配線やトランジスタを敷き詰める。そのため、それ以外の画素（Ｇ画素及びＢ画素）の下側には配線やトランジスタを極力配置しないようにするため、画素における配線の占める割合が低下し、図７に示すように空間が生じる。 In the present embodiment, as shown in FIG. 7, wirings and transistors are laid under one pixel (R pixel in the present embodiment) in the unit pixel region. Therefore, in order to minimize wiring and transistors below the other pixels (the G pixel and the B pixel), the ratio of the wiring in the pixel is reduced, and a space is generated as shown in FIG.
　第１の光電変換層１１１で吸収されずに透過した光は、第２の基板１０２における第２の光電変換層１１２に入射する前に、第１の基板１０１における第１の配線層１２１を構成する配線および第２の基板１０２における第２の配線層１２２を構成する配線に当たって反射する。しかし、本実施形態では、Ｇ画素及びＢ画素における配線の占める割合が低下しているため、Ｇ画素及びＢ画素において第２の基板１０２に入射する光量が増加する。これにより、Ｇ画素及びＢ画素において第２の光電変換部１１４の感度が向上する。 The light transmitted without being absorbed by the first photoelectric conversion layer 111 forms the first wiring layer 121 of the first substrate 101 before being incident on the second photoelectric conversion layer 112 of the second substrate 102. The light is reflected on the wirings to be formed and the wirings forming the second wiring layer 122 in the second substrate 102. However, in the present embodiment, since the ratio of the wiring in the G pixel and the B pixel is reduced, the amount of light incident on the second substrate 102 in the G pixel and the B pixel is increased. Thereby, the sensitivity of the second photoelectric conversion unit 114 is improved in the G pixel and the B pixel.
　撮像装置の回路構成について説明する。図８は、本実施形態に係る撮像装置の単位画素領域における画素部に関する回路構成を示す図である。なお、回路構成は、第１の基板と第２の基板で共通である。 The circuit configuration of the imaging device will be described. FIG. 8 is a diagram illustrating a circuit configuration related to a pixel unit in a unit pixel region of the imaging device according to the present embodiment. Note that the circuit configuration is common to the first substrate and the second substrate.
　２×２画素からなる単位画素領域では、４つのフォトダイオード（画素）ＰＤ１～ＰＤ４で１つのフローティングディフュージョン部（ＦＤ）を共有している。また、４つのフォトダイオードが、転送トランジスタ（ｔ－Ｔｒ１～ｔ－Ｔｒ４）以外のリセットトランジスタ（ｒ－Ｔｒ）、増幅トランジスタ（ａ－Ｔｒ）、および選択トランジスタ（ｓ－Ｔｒ）を共有した構成である。 In a unit pixel region composed of 2 × 2 pixels, one photodiode (pixel) PD1 to PD4 shares one floating diffusion portion (FD). The four photodiodes share a reset transistor (r-Tr), an amplification transistor (a-Tr), and a selection transistor (s-Tr) other than the transfer transistors (t-Tr1 to t-Tr4). is there.
　各画素のフォトダイオードＰＤ１～ＰＤ４は、入射光の光量に応じた電荷を蓄積する。各フォトダイオードに蓄積された電荷は、各画素の転送トランジスタを介してフローティングディフュージョン部に転送される。増幅トランジスタは、選択トランジスタを介して電流源とソースフォロワを構成し、フローティングディフュージョン部に蓄積された電荷に応じた電気信号を出力信号として、垂直信号線に出力する。なお、リセットトランジスタは、フローティングディフュージョン部の電荷を電源電圧ＶＤＤにリセットする。 (4) The photodiodes PD1 to PD4 of each pixel accumulate charges corresponding to the amount of incident light. The electric charge accumulated in each photodiode is transferred to the floating diffusion section via the transfer transistor of each pixel. The amplification transistor forms a current source and a source follower via the selection transistor, and outputs an electric signal corresponding to the electric charge accumulated in the floating diffusion portion to the vertical signal line as an output signal. Note that the reset transistor resets the charge in the floating diffusion portion to the power supply voltage VDD.
　垂直信号線に読み出された各画素の出力信号は、図示していない水平出力回路に行毎に一時的に保存された後、撮像素子から出力される。このようにして、撮像素子の各画素から、光量に応じた信号が読み出される。 (4) The output signal of each pixel read to the vertical signal line is temporarily stored for each row in a horizontal output circuit (not shown), and then output from the image sensor. In this way, a signal corresponding to the amount of light is read from each pixel of the image sensor.
　次に撮像装置の画素レイアウトについて説明する。図９は、本実施形態に係る撮像装置の単位画素領減のカラーフィルタの配置図を示す図である。図１０は、本実施形態に係る撮像装置の単位画素領域の画素レイアウトを示す図である。なお、単位画素領域は第１の基板１０１と第２の基板１０２とで共通のレイアウト構成であり、図１０は第１の基板１０１または第２の基板１０２における単位画素領減のイメージ図である。 Next, the pixel layout of the imaging device will be described. FIG. 9 is a diagram illustrating an arrangement diagram of a color filter of a unit pixel area of the imaging apparatus according to the present embodiment. FIG. 10 is a diagram illustrating a pixel layout of a unit pixel region of the imaging device according to the present embodiment. Note that the unit pixel region has a common layout configuration for the first substrate 101 and the second substrate 102, and FIG. 10 is an image diagram of the unit pixel area on the first substrate 101 or the second substrate 102.
　リセットトランジスタ（ｒ－Ｔｒ）は、拡散領域２１２と２１３をそれぞれソースおよびドレインとし、ゲート電極を有して形成される。また、増幅トランジスタ（ａ－Ｔｒ）は、拡散領域２１４と２１５をそれぞれドレインおよびソースとし、ゲート電極を有して形成される。また、選択トランジスタ（ｓ－Ｔｒ）は、拡散領域２１５と２１６をそれぞれドレインおよびソースとし、ゲート電極を有して形成される。 (4) The reset transistor (r-Tr) is formed with the diffusion regions 212 and 213 as a source and a drain, respectively, and with a gate electrode. Further, the amplification transistor (a-Tr) is formed to have the diffusion regions 214 and 215 as drains and sources, respectively, and to have a gate electrode. Further, the selection transistor (s-Tr) is formed with the diffusion regions 215 and 216 as drains and sources, respectively, and having a gate electrode.
　各画素のフォトダイオードＰＤ１～ＰＤ４は、それぞれの転送トランジスタ（ｔ－Ｔｒ１～ｔ－Ｔｒ４）に接続している。すなわち、転送トランジスタを介して、各画素のフォトダイオードＰＤ１～ＰＤ４は、フローティングディフュージョン部２１１に接続している。図中の太線２１７はフローティングディフュージョンの配線（ＦＤ配線）であり、ＦＤ配線によって、フローティングディフュージョン部２１１と、増幅トランジスタのゲート電極、およびリセットトランジスタのソース２１２が電気的に接続している。 (4) The photodiodes PD1 to PD4 of each pixel are connected to respective transfer transistors (t-Tr1 to t-Tr4). That is, the photodiodes PD1 to PD4 of each pixel are connected to the floating diffusion unit 211 via the transfer transistor. A thick line 217 in the drawing is a wiring of a floating diffusion (FD wiring), and the FD wiring electrically connects the floating diffusion portion 211 to the gate electrode of the amplification transistor and the source 212 of the reset transistor.
　増幅トランジスタのソースと選択トランジスタのドレインは共通の拡散領域２１５で形成されており、電気的に後続している。選択トランジスタのソースは、垂直信号線に電気的に接続している。また、リセットトランジスタのドレイン２１３、および増幅トランジスタのドレイン２１４が電源ＶＤＤに電気的に接続している。 (4) The source of the amplification transistor and the drain of the selection transistor are formed by a common diffusion region 215, and are electrically connected. The source of the selection transistor is electrically connected to the vertical signal line. In addition, the drain 213 of the reset transistor and the drain 214 of the amplification transistor are electrically connected to the power supply VDD.
　転送トランジスタを制御するための信号線（図示なし）は、第１の基板１０１または第２の基板１０２を横方向（列方向）に沿って配線されており、各転送トランジスタのゲート電極と接続している。同様に、リセットトランジスタを制御するための信号線、第１の基板１０１または第２の基板１０２を横方向（列方向）に沿って配置されており、リセットトランジスタのゲート電極と接続している。同様に、選択トランジスタを制御するための信号線は、第１の基板１０１または第２の基板１０２を横方向（列方向）に沿って配置されており、選択トランジスタのゲート電極と接続している。 A signal line (not shown) for controlling the transfer transistor is wired along the first substrate 101 or the second substrate 102 along the horizontal direction (column direction), and is connected to the gate electrode of each transfer transistor. ing. Similarly, a signal line for controlling the reset transistor, the first substrate 101 or the second substrate 102 is arranged along the horizontal direction (column direction), and is connected to the gate electrode of the reset transistor. Similarly, a signal line for controlling the selection transistor is arranged along the first substrate 101 or the second substrate 102 along the horizontal direction (column direction), and is connected to the gate electrode of the selection transistor. .
　上述のように、第１の光電変換層１１１および第２の光電変換層１１２の画素レイアウトでは、転送トランジスタは各画素に配置されているが、増幅トランジスタ、リセットトランジスタ、および選択トランジスタは、Ｒのカラーフィルタが配置された画素（Ｒ画素、図１０ではＰＤ２）に配置されている。Ｒ画素以外のＢ画素（Ｂのカラーフィルタが配置された画素、図１０ではＰＤ３）とＧ画素（Ｇのカラーフィルタが配置された画素、図１０ではＰＤ１とＰＤ４）における配線の占める割合が減少する。そのため、第２の光電変換部１１４のうちＢのカラーフィルタが設けられた画素（ＰＤ３）およびＧのカラーフィルタが設けられた画素（ＰＤ１とＰＤ４）に入射する光量が増加し、これらの画素における感度が向上する。 As described above, in the pixel layout of the first photoelectric conversion layer 111 and the second photoelectric conversion layer 112, the transfer transistor is disposed in each pixel, but the amplification transistor, the reset transistor, and the selection transistor It is arranged at the pixel (R pixel, PD2 in FIG. 10) on which the color filter is arranged. The proportion of wiring occupied by B pixels (pixels on which a color filter of B is arranged, PD3 in FIG. 10) and G pixels (pixels on which a color filter of G is arranged, PD1 and PD4 in FIG. 10) other than the R pixel decreases I do. Therefore, the amount of light incident on the pixel (PD3) provided with the B color filter and the pixels (PD1 and PD4) provided with the G color filter in the second photoelectric conversion unit 114 increases, and The sensitivity is improved.
　さらに、第２の光電変換層１１２の画素レイアウトでは、第２の光電変換部１１４のうちＲのカラーフィルタが設けられた画素のフォトダイオードＰＤ２は不要となるため、それ以外のフォトダイオードＰＤ１、ＰＤ３、ＰＤ４の面積が大きくなるように配置することができる。これにより、第２の光電変換層１１２におけるＢのカラーフィルタが設けられた画素およびＧのカラーフィルタが設けられた画素のフォトダイオードの面積が大きくなり、これらのフォトダイオードに入射する光量がさらに増加し、さらに感度の向上が見込める。 Further, in the pixel layout of the second photoelectric conversion layer 112, the photodiode PD2 of the pixel provided with the R color filter in the second photoelectric conversion unit 114 becomes unnecessary, and the other photodiodes PD1 and PD3 , PD4 can be arranged so as to increase the area. Accordingly, the photodiode area of the pixel provided with the B color filter and the pixel provided with the G color filter in the second photoelectric conversion layer 112 increases, and the amount of light incident on these photodiodes further increases. And further improvement in sensitivity can be expected.
　上述のように、本実施形態では、Ｒ画素の下に回路やトランジスタを敷き詰めた。Ｒ画素以外の箇所には最低でも転送トランジスタを配置していればよく、Ｒ画素直下にリセットトランジスタや選択トランジスタ等を配置する。また、図１０におけるＲ画素の下の第２の画素領域（ＰＤ２）の信号は、第２の光電変換部において隣接する単位画素領域（図示なし）の信号を用いて補正することができる。 As described above, in the present embodiment, circuits and transistors are spread under the R pixels. It is sufficient that at least a transfer transistor is disposed in a portion other than the R pixel, and a reset transistor, a selection transistor, and the like are disposed immediately below the R pixel. Further, the signal of the second pixel area (PD2) below the R pixel in FIG. 10 can be corrected using the signal of the adjacent unit pixel area (not shown) in the second photoelectric conversion unit.
　これにより、本実施形態では、Ｒ画素以外のＢ画素およびＧ画素の開口率は向上（配線領域が減少）し、第２の光電変換部に入射する光量が増加する。そして、従来の構造に比べて、第２の光電変換部で検出される信号のＳＮ比が向上する。第２の光電変換部のうちＢ画素およびＧ画素の下の領域においても、トランジスタを敷き詰める割合が少なくなるために、ＰＤ領域を広げることが可能となり、感度向上につながる。 According to this, in the present embodiment, the aperture ratio of the B pixel and the G pixel other than the R pixel is improved (the wiring area is reduced), and the amount of light incident on the second photoelectric conversion unit is increased. Then, as compared with the conventional structure, the SN ratio of the signal detected by the second photoelectric conversion unit is improved. In the region under the B pixel and the G pixel in the second photoelectric conversion unit, the rate of laying down the transistors is reduced, so that the PD region can be expanded, which leads to an improvement in sensitivity.
　（変形例１）
　第１実施形態の変形例１について説明する。図１１は、変形例１に係る撮像装置の断面の詳細を示す図である。図７に示す第１実施形態との違いは、第１の基板１０１と第２の基板１０２との問に、可視光をカットし赤外光のみを透過するフィルタ（可視光カットフィルタ）を挿入し、層間多層膜１３０を形成している点である。すなわち、上の画素と下の画素との間に、可視光カットフィルタからなる層間多層膜１３０を設けている。 (Modification 1)
Modification 1 of the first embodiment will be described. FIG. 11 is a diagram illustrating details of a cross section of the imaging device according to the first modification. The difference from the first embodiment shown in FIG. 7 is that a filter (visible light cut filter) that cuts visible light and transmits only infrared light is inserted between the first substrate 101 and the second substrate 102. The point is that the interlayer multilayer film 130 is formed. That is, the interlayer multilayer film 130 including the visible light cut filter is provided between the upper pixel and the lower pixel.
　第１の基板１０１において、波長が５００ｎｍ以下の光は全て吸収される。そのため、第２の光電変換部１１４のうち青色のカラーフィルタが設けられた領域には、赤外光のみが入射する。一方、第２の光電変換部１１４のうち緑色のカラーフィルタが設けられた領域には、第１の基板で吸収されなかった緑色の光が入射する。そこで、第１の基板１０１と第２の基板１０２との問に可視光カットフィルタを設けることにより、第２の光電変換部１１４に赤外光のみが入射する。このような構成により、本変形例では、第１実施形態の効果に加えて、第２の光電変換部１１４において赤外光を効率よく検出することができる。 (4) In the first substrate 101, all light having a wavelength of 500 nm or less is absorbed. Therefore, only infrared light is incident on a region of the second photoelectric conversion unit 114 where the blue color filter is provided. On the other hand, green light that has not been absorbed by the first substrate enters a region of the second photoelectric conversion unit 114 where the green color filter is provided. Therefore, by providing a visible light cut filter between the first substrate 101 and the second substrate 102, only infrared light enters the second photoelectric conversion unit 114. With such a configuration, in the present modification, in addition to the effect of the first embodiment, the second photoelectric conversion unit 114 can efficiently detect infrared light.
　（変形例２）
　第１実施形態の変形例２について説明する。図１２は、変形例２に係る撮像装置の断面の詳細を示す図である。図７に示す第１実施形態との違いは、第２の基板１０２において、第２の配線層１２２と第２の光電変換層１１２の位置を入れ替えて配置している点である。すなわち、本変形例の第２の基板１０２は、裏面照射型（ＢＳＩ)構造となっている。 (Modification 2)
Modification 2 of the first embodiment will be described. FIG. 12 is a diagram illustrating details of a cross section of the imaging device according to the second modification. The difference from the first embodiment shown in FIG. 7 is that, on the second substrate 102, the positions of the second wiring layer 122 and the second photoelectric conversion layer 112 are switched. That is, the second substrate 102 of the present modified example has a backside illumination (BSI) structure.
　第２の光電変換部１１４に入射する光の光路において、反射や散乱の要因となっていた第２の配線層１２２が無くなったため、第２の光電変換部１１４に入射する光量が増加し、第２の光電変換部１１４の感度が向上する。また、第２の光電変換部１１４を透過した赤外光は、第２の配線層１２２内の配線に反射して、再び第２の光電変換部１１４に入射するため、第２の光電変換部１１４の感度がさらに向上する。 In the optical path of the light incident on the second photoelectric conversion unit 114, the second wiring layer 122, which has been a factor of reflection and scattering, is eliminated, so that the amount of light incident on the second photoelectric conversion unit 114 increases. The sensitivity of the second photoelectric conversion unit 114 is improved. Further, the infrared light transmitted through the second photoelectric conversion unit 114 is reflected by the wiring in the second wiring layer 122 and is incident on the second photoelectric conversion unit 114 again. The sensitivity of 114 is further improved.
　なお、本変形例では、第２の配線層１２２を透過する光を考慮しなくてよいので、１つの画素（本実施形態ではＲ画素）の下側に、配線やトランジスタを集約する必要がない。すなわち、図１２に示すように、第２の配線層１２２では、各画素における配線の占める割合をほぼ同等にしてもよい。 In this modification, since it is not necessary to consider the light transmitted through the second wiring layer 122, it is not necessary to integrate wirings and transistors below one pixel (R pixel in the present embodiment). . That is, as shown in FIG. 12, in the second wiring layer 122, the proportion of the wiring in each pixel may be substantially equal.
　（第２実施形態）
　本発明の第２実施形態について説明する。図１３は、本発明の第２実施形態に係る撮像装置の断面の詳細を示す図である。図７に示す第１実施形態との違いは、青色のカラーフィルタが設けられた領域の第１の光電変換層１１１の厚み、緑色のカラーフィルタが設けられた領域の第１の光電変換層１１１の厚み、および赤色のカラーフィルタが設けられた領域の第１の光電変換層１１１の厚みが異なる点である。すなわち、Ｂ画素、Ｇ画素、Ｒ画素毎に、第１の光電変換層１１１の厚みを変える。 (2nd Embodiment)
A second embodiment of the present invention will be described. FIG. 13 is a diagram illustrating details of a cross section of the imaging device according to the second embodiment of the present invention. The difference from the first embodiment shown in FIG. 7 is that the thickness of the first photoelectric conversion layer 111 in the region where the blue color filter is provided and the first photoelectric conversion layer 111 in the region where the green color filter is provided Is different from the thickness of the first photoelectric conversion layer 111 in the region where the red color filter is provided. That is, the thickness of the first photoelectric conversion layer 111 is changed for each of the B pixel, the G pixel, and the R pixel.
　具体的には、第１の光電変換層１１１のうち、赤色のカラーフィルタが設けられた領域の厚みよりも、青色のカラーフィルタが設けられた領域と緑色のカラーフィルタが設けられた領域の厚みが薄くなるようにする。すなわち、Ｂ画素の第１の光電変換層の厚み、Ｇ画素の第１の光電変換層の厚み＜Ｒ画素の第１の光電変換層の厚みとなるようにする。 Specifically, in the first photoelectric conversion layer 111, the thickness of the region provided with the blue color filter and the thickness of the region provided with the green color filter are larger than the thickness of the region provided with the red color filter. Should be thinner. That is, the thickness of the first photoelectric conversion layer of the B pixel and the thickness of the first photoelectric conversion layer of the G pixel <the thickness of the first photoelectric conversion layer of the R pixel.
　このような構成により、青色のカラーフィルタが設けられた領域の第１の光電変換層１１１と緑色のカラーフィルタが設けられた領域の第１の光電変換層１１１における赤外光の吸収を抑えることができる。すなわち、第１の光電変換層１１１におけるＢ画素およびＧ画素の赤外光の吸収を抑えることができる。また、青色のカラーフィルタが設けられた領域の第２の光電変換層１１２と、緑色のカラーフィルタが設けられた領域の第２の光電変換層１１２に入射する赤外光の光量が増加し、第２の光電変換層１１２の感度が向上する。 With such a structure, absorption of infrared light in the first photoelectric conversion layer 111 in the region where the blue color filter is provided and the first photoelectric conversion layer 111 in the region where the green color filter is provided is suppressed. Can be. That is, absorption of infrared light of the B pixel and the G pixel in the first photoelectric conversion layer 111 can be suppressed. Further, the amount of infrared light incident on the second photoelectric conversion layer 112 in the region where the blue color filter is provided and the second photoelectric conversion layer 112 in the region where the green color filter is provided increases, The sensitivity of the second photoelectric conversion layer 112 is improved.
　上述の撮像措置の製造方法は以下のようになる。まず、青色のカラーフィルタおよび緑色のカラーフィルタが設けられた領域の第１の光電変換層１１１をドライエッチングすることにより、光透過材料１４０を埋め込むための穴を形成する。次に、ドライエッチングによって形成された穴に、光透過材料１４０を埋め込む。光透過材料１４０は光透過性が高い材料から形成されており、例えばＳｉＯ２やＳｉＮ等の透明材質や透明樹脂を用いて形成される。光透過材料１４０を埋め込んだ後、カラーフィルタ１０３を形成するために、第１の光電変換層１１１の表面を平坦化する。 製造 The manufacturing method of the above-mentioned imaging device is as follows. First, holes for embedding the light transmitting material 140 are formed by dry-etching the first photoelectric conversion layer 111 in a region where the blue color filter and the green color filter are provided. Next, the light transmitting material 140 is embedded in the hole formed by dry etching. The light transmitting material 140 is formed from a material having a high light transmitting property, and is formed using a transparent material such as SiO 2 or SiN or a transparent resin. After the light transmitting material 140 is embedded, the surface of the first photoelectric conversion layer 111 is flattened in order to form the color filter 103.
　本実施形態の原理について説明する。一般的には、Ｂ画素、Ｇ画素、Ｒ画素の感度がピークとなる波長は、図１４に示すように、それぞれ約４５０ｎｍ、５３０ｎｍ、６２０ｎｍである。図１４は、ＲＧＢ画素の分光感度の一例を示す図である。すなわち、青色のカラーフィルタが設けられた領域の第１の光電変換部１１３、緑色のカラーフィルタが設けられた領域の第１の光電変換部１１３、および赤色のカラーフィルタが設けられた領域の第１の光電変換部１１３の感度が最も高い波長は、それぞれ４５０ｎｍ、５３０ｎｍ、６２０ｎｍとみなすことができる。また、第２の光電変換部１１４で検出する光（赤外光）の波長を８００ｎｍとする。 原理 The principle of the present embodiment will be described. Generally, the wavelengths at which the sensitivities of the B pixel, the G pixel, and the R pixel peak are about 450 nm, 530 nm, and 620 nm, respectively, as shown in FIG. FIG. 14 is a diagram illustrating an example of the spectral sensitivity of the RGB pixels. That is, the first photoelectric conversion portion 113 in the region where the blue color filter is provided, the first photoelectric conversion portion 113 in the region where the green color filter is provided, and the first photoelectric conversion portion 113 in the region where the red color filter is provided. The wavelengths at which the sensitivity of the first photoelectric conversion unit 113 is highest can be regarded as 450 nm, 530 nm, and 620 nm, respectively. The wavelength of light (infrared light) detected by the second photoelectric conversion unit 114 is 800 nm.
　図１５は、４５０ｎｍ、５３０ｎｍ、６２０ｎｍ、および８００ｎｍの光がＳｉ内を任意の距離進んだ場合の光量をプロットしたグラフである。グラフの縦軸は光量を示し、Ｓｉ面に入射した光の強度を１としている。グラフの横軸は光が進んだ距離［ｕｍ］を示す。 FIG. 15 is a graph plotting the light amounts when 450 nm, 530 nm, 620 nm, and 800 nm light travels an arbitrary distance in Si. The vertical axis of the graph indicates the amount of light, and the intensity of light incident on the Si surface is set to 1. The horizontal axis of the graph indicates the distance [um] traveled by the light.
　図１５に示すように、４５０ｎｍの光は、Ｓｉ内を約１．０ｕｍ進んだ時にほとんど吸収される。また、５３０ｎｍの光は、Ｓｉ内を約１．６ｕｍ進んだ時に８０％吸収される。そのため、青色のカラーフィルタが設けられた領域の光電変換部１１３および緑色のカラーフィルタが設けられた領域の第１の光電変換部１１３で十分な感度を得るためには、それぞれ約１．０ｕｍ、約１．６ｕｍの膜厚があれば問題ない。 ４５０ As shown in FIG. 15, light of 450 nm is almost absorbed when traveling about 1.0 μm in Si. The 530 nm light is absorbed by 80% when it travels about 1.6 μm in Si. Therefore, in order to obtain sufficient sensitivity in the photoelectric conversion unit 113 in the region where the blue color filter is provided and the first photoelectric conversion unit 113 in the region where the green color filter is provided, each of about 1.0 μm, There is no problem if the thickness is about 1.6 μm.
　一般的なＢＳＩ構造のＳｉ層の膜厚は約３．０ｕｍであり、この時、８００ｎｍの光は約２５％吸収される。一方、Ｓｉ層の膜厚を約１．０ｕｍにした場合、８００ｎｍの光は約１０％吸収される。また、Ｓｉ層の膜厚を約１．６ｕｍにした場合、８００ｎｍの光は約１４％吸収される。そのため、画素毎にＳｉ層の膜厚を調整することによって、上の画素で吸収される赤外光の光量を低減させることができる。 膜厚 The thickness of the Si layer having a general BSI structure is about 3.0 μm, and at this time, about 25% of 800 nm light is absorbed. On the other hand, when the thickness of the Si layer is about 1.0 μm, about 10% of the 800 nm light is absorbed. When the thickness of the Si layer is set to about 1.6 μm, about 14% of the 800 nm light is absorbed. Therefore, by adjusting the thickness of the Si layer for each pixel, the amount of infrared light absorbed by the upper pixel can be reduced.
　例えば、青色のカラーフィルタが設けられた領域のＳｉ層の膜厚を約３．０ｕｍから約１．０ｕｍに薄くすることによって、青色のカラーフィルタが設けられた領域の第１の光電変換層１１１で吸収される赤外光の光量を約１５％低減できる。また、緑色のカラーフィルタが設けられた領域のＳｉ層の膜厚を約３．０ｕｍから約１．６ｕｍに薄くすることによって、緑色のカラーフィルタが設けられた領域の第１の光電変換層１１１で吸収される赤外光の光量を約１１％低減できる。 For example, by reducing the thickness of the Si layer in the region where the blue color filter is provided from about 3.0 μm to about 1.0 μm, the first photoelectric conversion layer 111 in the region where the blue color filter is provided is provided. Can reduce the amount of infrared light absorbed by about 15%. Further, by reducing the thickness of the Si layer in the region where the green color filter is provided from about 3.0 μm to about 1.6 μm, the first photoelectric conversion layer 111 in the region where the green color filter is provided is provided. Can reduce the amount of infrared light absorbed by about 11%.
　このように、Ｂ画素の第１の光電変換層の厚み、Ｇ画素の第１の光電変換層の厚み＜Ｒ画素の第１の光電変換層の厚みとなるようにすることにより、Ｂ画素およびＧ画素の第１の光電変換層１１１で吸収される赤外光の光量を低減でき、Ｂ画素およびＧ画素の第２の光電変換部１１４に入射する赤外光の光量が増加するため、感度が向上できる。 By setting the thickness of the first photoelectric conversion layer of the B pixel and the thickness of the first photoelectric conversion layer of the G pixel <the thickness of the first photoelectric conversion layer of the R pixel in this manner, the B pixel and the Since the amount of infrared light absorbed by the first photoelectric conversion layer 111 of the G pixel can be reduced and the amount of infrared light incident on the second photoelectric conversion unit 114 of the B pixel and the G pixel increases, the sensitivity increases. Can be improved.
　以上、本発明の一実施形態について説明したが、本発明の技術範囲は上記実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲において構成要素の組み合わせを変えたり、各構成要素に種々の変更を加えたり、削除したりすることができる。 As described above, one embodiment of the present invention has been described. However, the technical scope of the present invention is not limited to the above-described embodiment, and a combination of constituent elements may be changed without departing from the spirit of the present invention. Can be changed or deleted.
　上述の実施形態では、第１の基板１０１、第２の基板１０２ともに、２×２画素の４つの画素（光電変換部）から単位画素領域２００（光電変換グループ）が構成され、フローティングディフュージョン部（ＦＤ）を共有する例を説明したが、本発明はこれに限定されない。上側（第１の基板１０１）の２つ以上のフォトダイオード（画素）がＦＤを共有していればよい。すなわち、第１の基板１０１において、少なくとも２つの画素（第１の光電変換部１１３）が単位画素領域（第１の光電変換グループ）を形成し、この第１の光電変換グループに含まれる複数の第１の光電変換部で１つのフローティングディフュージョン部を共有していればよい。 In the above-described embodiment, both the first substrate 101 and the second substrate 102 form a unit pixel region 200 (photoelectric conversion group) from four 2 × 2 pixels (photoelectric conversion units), and the floating diffusion unit ( Although the example of sharing the FD) has been described, the present invention is not limited to this. It is sufficient that two or more photodiodes (pixels) on the upper side (first substrate 101) share the FD. That is, on the first substrate 101, at least two pixels (first photoelectric conversion units 113) form a unit pixel region (first photoelectric conversion group), and a plurality of pixels included in the first photoelectric conversion group. It is sufficient that the first photoelectric conversion unit shares one floating diffusion unit.
　この場合、複数の第１の光電変換部１１３のうち１つの第１の光電変換部とこの周囲のいずれかの位置において、配線とトランジスタの面積の和が、複数の第１の光電変換部のうち残りの第１の光電変換部よりも高密度で存在する第１の高密度領域（図１０では、ＰＤ２のある領域の周囲）が存在していればよい。 In this case, the sum of the area of the wiring and the area of the transistor at one of the first photoelectric conversion units 113 and at any position around the first photoelectric conversion unit 113 is equal to the sum of the area of the plurality of first photoelectric conversion units. The first high-density region (in FIG. 10, around the region where the PD 2 is located) that has a higher density than the remaining first photoelectric conversion units may be present.
　上側（第１の基板１０１）の単位画素領域（第１の光電変換グループ）に対応して、下側（第２の基板１０２）のフォトダイオード（画素）は少なくとも１つあればよい。すなわち、第２の基板１０２において、第２の光電変換部が、第１の光電変換グループに対応して少なくとも１つ設けられていればよい。このように、第１の基板１０１では複数の画素がＦＤを共有するが、第２の基板１０２では複数の画素がＦＤを共有しなくてもよい。 At least one photodiode (pixel) on the lower side (second substrate 102) should correspond to the unit pixel region (first photoelectric conversion group) on the upper side (first substrate 101). That is, on the second substrate 102, it is sufficient that at least one second photoelectric conversion unit is provided corresponding to the first photoelectric conversion group. As described above, a plurality of pixels share the FD in the first substrate 101, but a plurality of pixels do not need to share the FD in the second substrate 102.
　この場合、上述の第１の高密度領域でない領域（図１０では、ＰＤ１、ＰＤ３、ＰＤ４のある領域）の下に、第２の光電変換部が存在すればよい。 In this case, the second photoelectric conversion unit only needs to exist below the above-described first non-high-density area (the area where PD1, PD3, and PD4 exist in FIG. 10).
　上述の実施形態では、第１の基板１０１および第２の基板１０２における、各画素が同じ大きさである例を説明したが、本発明はこれに限定されない。例えば、第１の基板１０１に配置される画素と第２の基板１０２に配置される画素の大きさ（画素サイズ）が異なっていてもよい。 In the above-described embodiment, an example in which each pixel on the first substrate 101 and the second substrate 102 has the same size has been described, but the present invention is not limited to this. For example, the size (pixel size) of a pixel arranged on the first substrate 101 and a pixel arranged on the second substrate 102 may be different.
　第２の基板１０２において複数の画素がＦＤを共有している場合は、以下のようになる。少なくとも２つの第２の光電変換部１１４が第２の光電変換グループを形成し、第２の光電変換グループに含まれる複数の第２の光電変換部１１４で１つのフローティングディフュージョン部を共有する。この場合、複数の第２の光電変換部１１３のうち１つの第２の光電変換部とこの周囲のいずれかの位置において、配線とトランジスタの面積の和が複数の第２の光電変換部のうち残りの第２の光電変換部よりも高密度で存在する第２の高密度領域が、第１の基板１０１の第１の高密度領域が存在する第１の光電変換部とこの周囲のいずれかの位置の下にあればよい。 場合 When a plurality of pixels share the FD on the second substrate 102, the following is performed. At least two second photoelectric conversion units 114 form a second photoelectric conversion group, and a plurality of second photoelectric conversion units 114 included in the second photoelectric conversion group share one floating diffusion unit. In this case, the sum of the area of the wiring and the area of the transistor at one of the second photoelectric conversion units 113 and at any position around the second photoelectric conversion unit 113 among the plurality of second photoelectric conversion units 113 is determined. The second high-density region existing at a higher density than the remaining second photoelectric conversion unit is any one of the first photoelectric conversion unit of the first substrate 101 where the first high-density region exists and one of the first photoelectric conversion unit and its surroundings. It should just be under the position of.
　上述の実施形態では、全てのトランジスタを、１つのフォトダイオード（高密度領域）に集約して配置している例を説明したが、本発明はこれに限定されない。例えば、一番面積の大きい増幅トランジスタだけを、高密度領域（第１の高密度領域、第２の高密度領域）に配置してもよい。 In the above-described embodiment, an example has been described in which all the transistors are collectively arranged in one photodiode (high-density region), but the present invention is not limited to this. For example, only the amplification transistor having the largest area may be arranged in the high-density region (first high-density region, second high-density region).
　上述の実施形態では、第１の高密度領域がＲフィルタの直下の領域の第１の光電変換部の面位置に設けられている例を説明したが、本発明はこれに限定されない。例えば、第１の高密度領域がＧフィルタの直下の領域の第１の光電変換部の面位置に設けられていてもよい。 In the above-described embodiment, an example has been described in which the first high-density region is provided at the surface position of the first photoelectric conversion unit immediately below the R filter, but the present invention is not limited to this. For example, the first high-density region may be provided at a surface position of the first photoelectric conversion unit in a region immediately below the G filter.
　上述のように、第１の基板１０１の第１の配線層１２１と、第２の基板１０２の第２の配線層１２２が向かい合わせて設けられている場合（図７、図１１、図１３）、第１の基板１０１において、第１の配線層１２１内の配線（およびトランジスタ）は第１の高密度領域内に配置される。また、第２の基板１０２において、第２の配線層１２２内の配線（およびトランジスタ）は第２の高密度領域内に配置される。 As described above, the case where the first wiring layer 121 of the first substrate 101 and the second wiring layer 122 of the second substrate 102 are provided to face each other (FIGS. 7, 11, and 13) In the first substrate 101, wirings (and transistors) in the first wiring layer 121 are arranged in a first high-density region. Further, in the second substrate 102, the wiring (and the transistor) in the second wiring layer 122 is arranged in the second high-density region.
　第１の基板１０１の第１の配線層１２１が第１の光電変換部１１３の下に設けられ、第２の基板１０２の第２の配線層１２２が第２の光電変換部１１４の下に設けられる場合（図１２）、第１の基板１０１において、第１の配線層１２１内の配線（およびトランジスタ）は第１の高密度領域内に配置される。この時、第２の基板１０２において、第２の配線層１２２内の配線（およびトランジスタ）が第２の高密度領域内に配置されてもよいし、第２の配線層１２２内の配線（およびトランジスタ）が均等に配置されていてもよい。 A first wiring layer 121 of the first substrate 101 is provided below the first photoelectric conversion unit 113, and a second wiring layer 122 of the second substrate 102 is provided below the second photoelectric conversion unit 114. In this case (FIG. 12), in the first substrate 101, the wiring (and the transistor) in the first wiring layer 121 is arranged in the first high-density region. At this time, in the second substrate 102, the wiring (and the transistor) in the second wiring layer 122 may be arranged in the second high-density region, or the wiring (and the transistor) in the second wiring layer 122 may be arranged. Transistors) may be evenly arranged.
　上述のように、第２の光電変換層１１２においてＲフィルタが設けられた画素のフォトダイオードＰＤ２は不要となるため、それ以外のフォトダイオードＰＤ１、ＰＤ３、ＰＤ４の面積が大きくなるように配置してもよい。すなわち、第２の光電変換層１１２において、Ｒフィルタに対応する第２の光電変換部（フォトダイオードＰＤ２）がなくてもよい。 As described above, since the photodiode PD2 of the pixel provided with the R filter in the second photoelectric conversion layer 112 becomes unnecessary, the photodiodes PD1, PD3, and PD4 are arranged so that the areas of the other photodiodes PD1, PD3, and PD4 are large. Is also good. That is, the second photoelectric conversion layer 112 may not include the second photoelectric conversion unit (photodiode PD2) corresponding to the R filter.
　本明細書において「前、後ろ、上、下、右、左、垂直、水平、縦、横、行および列」などの方向を示す言葉は、本発明の装置におけるこれらの方向を説明するために使用している。従って、本発明の明細書を説明するために使用されたこれらの言葉は、本発明の装置において相対的に解釈されるべきである。 As used herein, words indicating direction such as "front, back, top, bottom, right, left, vertical, horizontal, vertical, horizontal, row and column" are used to describe these directions in the device of the present invention. I'm using Therefore, these terms used to describe the specification of the present invention should be interpreted relatively in the device of the present invention.
　本発明は、可視光画像と赤外光画像を同時に取得する積層型の撮像装置に広く適用でき、第２の光電変換層（下側のフォトダイオード）に入射する光量の低下を抑制することができる。 INDUSTRIAL APPLICABILITY The present invention can be widely applied to a stacked-type imaging device that simultaneously acquires a visible light image and an infrared light image, and suppresses a decrease in the amount of light incident on the second photoelectric conversion layer (lower photodiode). it can.
　１００　撮像装置
　１０１　第１の基板
　１０２　第２の基板
　１０３　カラーフィルタ
　１０４　接続部
　１１１　第１の光電変換層
　１１２　第２の光電変換層
　１１３　第１の光電変換部（画素）
　１１４　第２の光電変換部（画素）
　１１５　ＭＯＳトランジスタ
　１２１　第１の配線層
　１２２　第２の配線層
　１２３　配線
　１２４　層間絶縁膜
　１３０　層間多層膜（可視光カットフィルタ）
　１４０　光透過材料
　２００　単位画素領域（光電変換グループ）
　２０１～２０３、３０１～３０３・・・画素
　２１１　フローティングディフュージョン部
　２１２～２１６　拡散領域
　２１７　ＦＤ配線
　ＰＤ１、ＰＤ３、ＰＤ４　フォトダイオード（高密度領域でない領域）
　ＰＤ２　フォトダイオード（高密度領域）
　ａ－Ｔｒ　増幅トランジスタ
　ｒ－Ｔｒ　リセットトランジスタ
　ｓ－Ｔｒ　選択トランジスタ
　ｔ－Ｔｒ１～ｔ－Ｔｒ４　転送トランジスタ REFERENCE SIGNS LIST 100 imaging device 101 first substrate 102 second substrate 103 color filter 104 connection portion 111 first photoelectric conversion layer 112 second photoelectric conversion layer 113 first photoelectric conversion portion (pixel)
114 second photoelectric conversion unit (pixel)
115 MOS transistor 121 1st wiring layer 122 2nd wiring layer 123 wiring 124 Interlayer insulating film 130 Interlayer multilayer film (visible light cut filter)
140 light transmitting material 200 unit pixel area (photoelectric conversion group)
201 to 203, 301 to 303 ... Pixel 211 Floating diffusion part 212 to 216 Diffusion area 217 FD wiring PD1, PD3, PD4 Photodiode (area other than high density area)
PD2 photodiode (high density area)
a-Tr amplifying transistor r-Tr reset transistor s-Tr selection transistor t-Tr1 to t-Tr4 transfer transistor

Claims (11)

  1. 　複数の第１の光電変換部を有する第１の基板と、前記第１の基板に積層して設けられ複数の第２の光電変換部を有する第２の基板と、を備える固体撮像装置であって、
    　前記第１の基板において、
    　　前記複数の第１の光電変換部のうち少なくとも２つの第１の光電変換部が第１の光電変換グループを形成し、
    　　前記第１の光電変換グループに含まれる複数の第１の光電変換部で１つのフローティングディフュージョン部を共有し、
    　　前記複数の第１の光電変換部のうち１つの第１の光電変換部とこの周囲において、配線とトランジスタの面積の和が、前記複数の第１の光電変換部のうち残りの第１の光電変換部よりも高密度で存在する第１の高密度領域が存在し、
    　前記第２の基板において、
    　　前記複数の第２の光電変換部は、前記第１の光電変換グループに対応して少なくとも１つ設けられ、
    　　前記第１の高密度領域でない領域の下に、前記複数の第２の光電変換部が存在する
    　ことを特徴とする固体撮像装置。     A solid-state imaging device including: a first substrate having a plurality of first photoelectric conversion units; and a second substrate having a plurality of second photoelectric conversion units provided to be stacked on the first substrate. hand,
    In the first substrate,
    At least two first photoelectric conversion units among the plurality of first photoelectric conversion units form a first photoelectric conversion group;
    A plurality of first photoelectric conversion units included in the first photoelectric conversion group share one floating diffusion unit;
    In one of the plurality of first photoelectric conversion units and the periphery of one of the first photoelectric conversion units, the sum of the area of the wiring and the transistor is equal to the remaining first photoelectric conversion unit of the plurality of first photoelectric conversion units. There is a first high-density region that exists at a higher density than the conversion unit,
    In the second substrate,
    At least one of the plurality of second photoelectric conversion units is provided corresponding to the first photoelectric conversion group,
    The solid-state imaging device, wherein the plurality of second photoelectric conversion units exist below a region other than the first high-density region.
  2. 　前記第２の基板において、
    　　前記複数の第２の光電変換部のうち少なくとも２つの第２の光電変換部が第２の光電変換グループを形成し、
    　　前記第２の光電変換グループに含まれる複数の第２の光電変換部で１つのフローティングディフュージョン部を共有し、
    　　前記複数の第２の光電変換部のうち１つの第２の光電変換部とこの周囲において、配線とトランジスタの面積の和が前記複数の第２の光電変換部のうち残りの第２の光電変換部よりも高密度で存在する第２の高密度領域が、前記第１の高密度領域と同じ位置にある
    　ことを特徴とする、請求項１に記載の固体撮像装置。     In the second substrate,
    At least two second photoelectric conversion units among the plurality of second photoelectric conversion units form a second photoelectric conversion group;
    A plurality of second photoelectric conversion units included in the second photoelectric conversion group share one floating diffusion unit;
    In one of the plurality of second photoelectric conversion units and the periphery thereof, the sum of the area of the wiring and the transistor is equal to the remaining second photoelectric conversion unit of the plurality of second photoelectric conversion units. 2. The solid-state imaging device according to claim 1, wherein a second high-density region existing at a higher density than the portion is located at the same position as the first high-density region. 3.
  3. 　前記第１の高密度領域は、少なくとも増幅トランジスタを含むことを特徴とする、請求項１に記載の固体撮像装置。 The solid-state imaging device according to claim 1, wherein the first high-density region includes at least an amplification transistor.
  4. 　前記第１の高密度領域または前記第２の高密度領域は、少なくとも増幅トランジスタを含むことを特徴とする、請求項２に記載の固体撮像装置。 The solid-state imaging device according to claim 2, wherein the first high-density region or the second high-density region includes at least an amplification transistor.
  5. 　前記第１の基板の上に配置され、可視領域と赤外領域に透過帯域を有するカラーフィルタをさらに備え、
    　前記複数の第１の光電変換部は、前記カラーフィルタを透過した光の露光量に応じた第１の信号電荷を出力し、
    　複数の前記第２の光電変換部は、少なくとも赤外領域に感度を有し、前記第１の基板を透過した光の露光量に応じた第２の信号電荷を出力することを特徴とする、請求項１～４のいずれか１項に記載の固体撮像装置。     A color filter disposed on the first substrate and having a transmission band in a visible region and an infrared region,
    The plurality of first photoelectric conversion units output a first signal charge according to an exposure amount of light transmitted through the color filter,
    The plurality of second photoelectric conversion units have sensitivity at least in an infrared region, and output a second signal charge according to an exposure amount of light transmitted through the first substrate. The solid-state imaging device according to any one of claims 1 to 4.
  6. 　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、
    　前記第１の高密度領域は、前記Ｒフィルタの直下の前記第１の光電変換部の面位置に設けられることを特徴とする、請求項５に記載の固体撮像装置。     The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region.
    The solid-state imaging device according to claim 5, wherein the first high-density region is provided at a surface position of the first photoelectric conversion unit immediately below the R filter.
  7. 　前記第１の基板の第１の配線層と、前記第２の基板の第２の配線層は向かい合わせて設けられ、
    　前記第１の基板において、前記第１の配線層内の配線は前記第１の高密度領域内に配置され、
    　前記第２の基板において、前記第２の配線層内の配線は前記第２の高密度領域内に配置されることを特徴とする、請求項２または４に記載の固体撮像装置。     A first wiring layer of the first substrate and a second wiring layer of the second substrate are provided to face each other;
    In the first substrate, the wiring in the first wiring layer is arranged in the first high-density region,
    The solid-state imaging device according to claim 2, wherein, in the second substrate, wiring in the second wiring layer is arranged in the second high-density region.
  8. 　前記第１の基板の第１の配線層は前記第１の光電変換部の下に設けられ、前記第２の基板の第２の配線層は、前記第２の光電変換部の下に設けられ、
    　前記第１の基板において、前記第１の配線層内の配線は前記第１の高密度領域内に配置されることを特徴とする、請求項１～６のいずれか１項に記載の固体撮像装置。     A first wiring layer of the first substrate is provided below the first photoelectric conversion unit, and a second wiring layer of the second substrate is provided below the second photoelectric conversion unit. ,
    The solid-state imaging device according to any one of claims 1 to 6, wherein, in the first substrate, a wiring in the first wiring layer is arranged in the first high-density region. apparatus.
  9. 　前記第１の基板と前記第２の基板との間に、可視光をカットし赤外光を透過するフィルタが設けられることを特徴とする、請求項１～８のいずれか１項に記載の固体撮像装置。 The filter according to any one of claims 1 to 8, wherein a filter that cuts visible light and transmits infrared light is provided between the first substrate and the second substrate. Solid-state imaging device.
  10. 　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、
    　前記第１の光電変換部は、前記カラーフィルタの下の第１の光電変換層内に配置され、
    　前記Ｂフィルタが配置される領域の第１の前記光電変換層の厚みおよび前記Ｇフィルタが配置される領域の前記第１の光電変換層の厚みよりも、前記Ｒフィルタが配置される領域の前記第１の光電変換層の厚みが厚いことを特徴とする、請求項５に記載の固体撮像装置。     The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region.
    The first photoelectric conversion unit is disposed in a first photoelectric conversion layer below the color filter,
    Than the thickness of the first photoelectric conversion layer in the region where the B filter is arranged and the thickness of the first photoelectric conversion layer in the region where the G filter is arranged, The solid-state imaging device according to claim 5, wherein the thickness of the first photoelectric conversion layer is large.
  11. 　前記カラーフィルタは、Ｒの可視領域を透過させるＲフィルタ、Ｇの可視領域を透過させるＧフィルタ、Ｂの可視領域を透過させるＢフィルタから構成され、
    　前記第２の光電変換部は、第２の光電変換層内に配置され、
    　前記第２の光電変換層において、前記Ｒフィルタに対応する前記第２の光電変換部が存在しないことを特徴とする、請求項５に記載の固体撮像装置。     The color filter includes an R filter that transmits an R visible region, a G filter that transmits a G visible region, and a B filter that transmits a B visible region.
    The second photoelectric conversion unit is disposed in a second photoelectric conversion layer,
    The solid-state imaging device according to claim 5, wherein the second photoelectric conversion layer does not include the second photoelectric conversion unit corresponding to the R filter.
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