WO2024086959A1 - Stacked sensor for simultaneouly detecting visible light and infrared light - Google Patents

Stacked sensor for simultaneouly detecting visible light and infrared light Download PDF

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Publication number
WO2024086959A1
WO2024086959A1 PCT/CN2022/126881 CN2022126881W WO2024086959A1 WO 2024086959 A1 WO2024086959 A1 WO 2024086959A1 CN 2022126881 W CN2022126881 W CN 2022126881W WO 2024086959 A1 WO2024086959 A1 WO 2024086959A1
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sensor
infrared
band
layer
sensor layer
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PCT/CN2022/126881
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French (fr)
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Makoto Monoi
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Huawei Technologies Co., Ltd.
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Priority to PCT/CN2022/126881 priority Critical patent/WO2024086959A1/en
Publication of WO2024086959A1 publication Critical patent/WO2024086959A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/1462—Coatings
    • H01L27/14621—Colour filter arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
    • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
    • H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
    • H01L21/822—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components the substrate being a semiconductor, using silicon technology
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14645—Colour imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14649—Infrared imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0203—Containers; Encapsulations, e.g. encapsulation of photodiodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Definitions

  • the present invention relates to image sensors, and more specifically to sensors that capture visible light (visible light, RGB) and infrared (infrared light, IR) images simultaneously.
  • a sensor that can capture visible light and infrared signals with a single sensor.
  • visible light pixels and infrared light pixels are laid out in a two-dimensional array.
  • a dual band pass filter that passes a specific band of visible light and a specific band of infrared light.
  • Visible pixels are fitted with filters to block specific bands of infrared light, and infrared pixels are fitted with filters to block visible light.
  • visible and infrared signals are captured simultaneously by replacing a part of visible pixels laid out in a two-dimensional array with infrared pixels.
  • three of the four pixel groups are used for visible light (R, G, B) detection and the remaining one is used for infrared (IR) detection.
  • IR infrared
  • the infrared pixels and the visible pixels are placed adjacent to each other, so that infrared rays easily leak into the visible pixels.
  • the shielding characteristics of the infrared shielding filter are insufficient, infrared rays leak into visible light pixels. Therefore, the problem of color mixing tends to arise.
  • Another example shows another example of a sensor that can capture visible light and infrared signals with a single sensor.
  • a silicon photodiode layer for reading visible light signals and a photoelectric film layer for reading infrared signals are stacked.
  • a visible-light pixel color filter which is an interference type that transmits a specific color signal through it, is used to suppress the mixing of infrared rays into the visible-light signal and improve color reproducibility.
  • the pixels of the sensor are laid out in a two-dimensional array, and as in the previous example, only one of the four pixel groups is used for infrared (IR) detection, and thus the resolution of the infrared image is low.
  • Another aspect of this example is the use of a color filter, a pigment-type that passes specific color and infrared signals, that increases the resolution of the infrared image by detecting visible and infrared light in different layers at each pixel of the sensor.
  • the infrared signal is mixed with the visible light signal, and color reproducibility is degraded.
  • the objective of the invention is to solve the above problem in a conventional sensor capable of capturing visible light and infrared signals with a single sensor. These include low resolution of infrared images due to the small number of pixels, reduced sensitivity of visible-light images due to visible-light pixel color filters, and degraded color reproducibility due to the mixing of infrared light into visible-light pixels.
  • an embodiment of the present invention provides a sensor.
  • the sensor includes a dual band pass filter, a first sensor layer, and a second sensor layer in stacked order from an object side.
  • the first sensor layer comprises a plurality of first pixels
  • the second sensor layer comprises a plurality of second pixels.
  • the sensor detects a first band of light passing through the dual band pass filter at the first sensor layer, and detects a second band of light passing through the dual band pass filter at the second sensor layer.
  • the first band of the dual band pass filter corresponds to visible light
  • the second band of the dual band pass filter corresponds to infrared light
  • the first band passes a specific band of visible light
  • the second band passes a specific band of infrared light
  • the second band of the dual band pass filter has its short wavelength end of transmission band for the infrared light located at greater than or equal to 1000 nm.
  • the plurality of first pixels in the first sensor layer are a plurality of photodiodes, and each of the photodiodes generates a signal charge according to visible light in the specific wavelength band.
  • the first sensor layer further comprises a color filter to pass through the specific wavelength band of visible light.
  • the first sensor layer further comprises an infrared light cut filter to block the specific band of infrared light.
  • the infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and a long wavelength end of the transmission band for visible light in the first band of the dual band pass filter is located within the absorption band of the infrared cut filter.
  • the first sensor layer further comprises a plurality of microlenses, and each of the plurality of microlenses corresponds to one or more of corresponding first pixels of the plurality of first pixels.
  • the plurality of second pixels in the second sensor layer are a plurality of infrared pixels, and each of the infrared pixels generates a signal charge according to infrared light of a certain wavelength or greater.
  • each of the plurality of second pixels is connected to a readout circuit of the first sensor layer by a Cu-Cu coupling.
  • the second sensor layer further comprises an infrared pass filter to pass through infrared light of the certain wavelength or greater.
  • the second sensor layer comprises a photoelectric conversion film having the plurality of second pixels.
  • the photoelectric conversion film in the second sensor layer is made of quantum dots, an organic layer, a Ge-Si layer, a Si-layer, or an InGaAs layer.
  • the sensor acquires depth information by Time of Flight (TOF) by using the photoelectric conversion film in the second sensor layer.
  • TOF Time of Flight
  • an embodiment of the present invention provides a method of manufacturing a sensor.
  • the sensor comprises a dual band pass filter, a first sensor layer, and a second sensor layer in stacked order from an object side.
  • the method comprises constructing the first sensor layer by laminating a color filter to pass through a specific wavelength band of visible light and a plurality of photodiodes on one silicon layer, constructing the second sensor layer with a photoelectric conversion film having a plurality of infrared pixels over another silicon layer, and connecting each of the plurality of infrared pixels to readout circuits of the first sensor layer by using a Cu-Cu coupling.
  • the second sensor layer further comprises an infrared pass filter laminated on the photoelectric conversion film to pass through infrared light of a specific wavelength or greater.
  • the method further comprises constructing a plurality of microlenses on the first sensor layer, and each of the plurality of microlenses corresponds to one or more of corresponding photodiodes of the plurality of photodiodes.
  • the dual band pass filter has a characteristic to pass through the specific wavelength band of visible light and to pass through infrared light of the specific wavelength or greater, and has its short wavelength end of transmission band for the infrared light located at greater or equal to 1000 nm.
  • the method further comprises laminating an infrared cut filter to block infrared light of a specific band on the first sensor layer.
  • the infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and a long wavelength end of the transmission band for visible light in the dual band pass filter is located within the absorption band of the infrared cut filter.
  • FIG. 1 shows a cross-sectional view of the configuration of the sensor according to the first embodiment of the present invention.
  • FIG. 2 is a graph showing the characteristics of each filter used in the first embodiment.
  • FIG. 3 is a graph showing the characteristics of each pixel used in the first embodiment.
  • FIG. 4 is a schematic diagram showing the arrangement of pixels in the first embodiment.
  • FIG. 5 is a graph showing the resulting spectral sensitivity in the first embodiment.
  • FIG. 6 shows the transmission band of the dual band pass filter used in the second embodiment of the present invention.
  • FIG. 7 is a graph showing the resulting spectral sensitivity in the second embodiment.
  • FIG. 8 shows a cross-sectional view of the configuration of the sensor according to the third embodiment of the present invention.
  • FIG. 9 shows the transmission bands of the dual band pass filter and the infrared cut filter used in the third embodiment.
  • FIG. 10 is a graph showing the resulting spectral sensitivity in the third embodiment.
  • FIG. 11 shows a cross-sectional view of the configuration of the sensor according to the fourth embodiment of the present invention.
  • FIG. 12 shows a cross-sectional view of the configuration of the sensor according to the fifth embodiment of the present invention.
  • FIG. 1 shows a cross-sectional view of the configuration of a sensor 1 according to the first embodiment of the present invention.
  • a dual band pass filter (DBPF) 10 is arranged on a sensor body, and a first sensor layer 11 and a second sensor layer 12 are laminated on the sensor body.
  • DBPF dual band pass filter
  • light enters the sensor body through a dual band pass filter 10 from above the figure, then, passes through the first sensor layer 11, and reaches the second sensor layer 12.
  • a microlens (i.e. on chip lens, OCL) 111 is placed at the top of the sensor body to focus light.
  • a dual band pass filter 10 transmits light in specific bands of visible light and infrared light.
  • the first sensor layer 11 comprises a color filter 112 and a silicon layer 113.
  • the color filter 112 transmits a specific band of visible light.
  • a plurality of photodiodes (PD) 114 are arrayed as pixels in an array to generate signal charges according to the specific band of light transmitted.
  • the signal charge generated by the PD is converted into a voltage signal by a readout circuit 115.
  • the second sensor layer 12 comprises an infrared (IR) pass filter 121 and a photoelectric conversion film 122.
  • the infrared pass filter 121 is a color filter that transmits infrared rays over a certain wavelength.
  • the photoelectric conversion film 122 has infrared sensitivity, for example, a quantum dot film sensitive to short wave infrared region (SWIR) provided as SID 2021 made by STMicroelectronics may be used.
  • SWIR quantum dot film sensitive to short wave infrared region
  • the infrared pass filter 121 and the photoelectric conversion film 122 are formed on another silicon layer 123 in the second sensor layer 12.
  • Infrared pixels are arranged in an array configuration in the photoelectric conversion film 122, and each pixel is connected to the readout circuit 115 of the first sensor layer 11 by a Cu-Cu coupling 116, and its signal charge is converted into a voltage signal.
  • the photoelectric conversion film 122 may be an organic layer, a Ge-Si layer, a Si layer, or an InGaAs layer in addition to the quantum dots.
  • FIG. 2 is a graph showing the characteristics of each filter used in the first embodiment.
  • the thick solid line indicates the transmission band of the dual band pass filter 10, which includes the first band corresponding to visible light and the second band corresponding to infrared light.
  • Three solid lines indicate transmission bands for each color (R, G, B) of the color filter 112, corresponding to blue (B) , green (G) , and red (R) from the left to the right.
  • the thick dashed line indicates the transmission band of the infrared pass filter 121.
  • the horizontal axis of the graph represents the wavelength of light in nanometers (nm)
  • the vertical axis of the graph represents transmittance.
  • FIG. 3 is a graph showing the characteristics of each pixel used in the first embodiment.
  • the thick solid line indicates the absorption characteristics of the photodiode (PD) 114 in the silicon layer 113 of the first sensor layer 11.
  • the thick dashed line indicates the absorption characteristics of the photoelectric conversion film 122 on the silicon layer 123 in the second sensor layer 12.
  • the horizontal axis of the graph represents the wavelength of light in nanometers (nm) similarly to FIG. 2, and the vertical axis of the graph represents absorptance.
  • FIG. 4 is a schematic diagram showing the arrangement of pixels in this embodiment.
  • the first sensor layer 11 and the second sensor layer 12 are shown partially overlapping.
  • the figure on the left side corresponds to the first sensor layer 11, and, for each color of visible light, photodiodes as visible light pixels are arranged as shown in the figure.
  • the figure on the right side corresponds to the second sensor layer 12 placed below the first sensor layer 11, and the infrared pixels are arranged so as to correspond to the pixels (R, G, B) of the first sensor layer 11, so that infrared light can be detected at all the pixels.
  • the visible light (R, G, B) passing through the first band of the dual band pass filter 10 is detected in the first sensor layer 11, and then, for the light passing through the first sensor layer 11, the infrared light passing through the second band of the dual band pass filter 10 is detected in the corresponding pixel of the second sensor layer 12 placed below it.
  • the microlens (OCL) 111 on the top of the sensor body can be arranged so that each of microlens corresponds to a corresponding pixel of the sensor body.
  • FIG. 5 is a graph showing the resulting spectral sensitivity in the first embodiment.
  • B blue
  • G green
  • R red
  • a peak around the wavelength of 900 nm-1000 nm This shows that each color component of visible light and infrared light can be detected using a single sensor 1.
  • IR_G three lines for IR_G, IR_B, and IR_R are almost overlapping.
  • a small peak of sensitivity of visible light is found to overlap in the infrared band. This shows that in the 900 -1000 nm range, the infrared component is leaking into the visible light, which means that mixed color occurs somewhat in this range.
  • FIG. 6 shows the transmission band of the dual band pass filter 10 used in the second embodiment.
  • the difference in the transmission band is that the shorter wavelength side in the second band for infrared light is set to be 1000 nm or greater, and for the longer wavelength bands about 100%of light is transmitted.
  • FIG. 7 is a graph showing the resulting spectral sensitivity in the second embodiment.
  • the sensitivity of visible light is missing in the infrared band. That is, the infrared component does not leak into visible light, and the problem of color mixing is solved.
  • the transmission band of the dual band pass filter 10 has been changed such that approximately 100%of light can be transmitted in the wavelength band of 1000 nm or greater, thereby expanding the detection range of infrared light.
  • FIG. 8 shows a cross-sectional view of the configuration of sensor 1 according to the third embodiment of the present invention.
  • an infrared cut filter 130 is added above the color filter 112 in the first sensor layer 11.
  • the infrared cut filter 130 is for blocking a specific band of infrared light.
  • FIG. 9 shows the transmission bands of the dual band pass filter 10 and the infrared cut filter 130 used in the third embodiment.
  • characteristics of the dual band pass filter may have incident angle dependence, for example, if it is formed only with a multilayer reflective film.
  • the dual band pass filter 10 has an angular dependence of filter characteristics on incident light. In a case of the incident angle being 30 degrees, as compared with the characteristics when the incident angle is 0 degrees which is shown by the thick solid line in Fig. 9, the transmission band overall shifts to the shorter wavelength side as shown by the thick broken line.
  • the infrared cut filter 130 is formed using an absorber, the filter characteristics have no angular dependence on incident light.
  • the long wavelength end of the transmission band of the first band corresponding to the visible light (R, G, B) of the dual band pass filter 10 is arranged so as to be within the absorption band of the infrared cut filter 130.
  • FIG. 10 is a graph showing the resulting spectral sensitivity in the third embodiment.
  • the dashed line shows the characteristics of the case where the incident angle is 30 degrees, and it can be seen that the characteristics of the case where the incident angle is 0 degree shown by the solid line is almost overlapping. It should be noted that in the infrared band also characteristics of two cases are almost overlapping.
  • FIG. 11 shows a cross-sectional view of the configuration of the sensor 1 according to the fourth embodiment of the present invention.
  • the infrared pixels in the photoelectric conversion film 122 of the second sensor layer 12 are connected to a readout circuit 240 formed in the silicon layer 123 of the second sensor layer 12, instead of the readout circuit 115 of the first sensor layer 11.
  • the Cu-Cu coupling 116 is not required and the process of manufacturing the sensor 1 can be simplified.
  • FIG. 12 shows a cross-sectional view of the configuration of the sensor 1 according to the fifth embodiment of the present invention.
  • the fifth embodiment uses infrared pixels as a time-of-flight (TOF) sensor.
  • TOF time-of-flight
  • irPD infrared pixel
  • Ge-Si layer which is the photoelectric conversion film 122 of the second sensor layer 12
  • the indirect TOF of a continuous waveform system can be obtained.
  • depth information can also be acquired by the sensor.

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Abstract

Tasks To provide a sensor that can detect both visible light and infrared light, which shows sufficient resolution of infrared images and sensitivity of visible-light images. Means of Solution The sensor includes a dual band pass filter, a first sensor layer, and a second sensor layer in stacked order from an object side. The first sensor layer comprises a plurality of first pixels and the second sensor layer comprises a photoelectric conversion film having a plurality of second pixels. The sensor detects a first band of light passing through the dual band pass filter at the first sensor layer, and detects a second band of light passing through the dual band pass filter at the second sensor layer.

Description

STACKED SENSOR FOR SIMULTANEOULY DETECTING VISIBLE LIGHT AND INFRARED LIGHT TECHNICAL FIELD
The present invention relates to image sensors, and more specifically to sensors that capture visible light (visible light, RGB) and infrared (infrared light, IR) images simultaneously.
BACKGROUND
In recent years, there has been a demand in industry for a single sensor that can read visible light and infrared images simultaneously. However, in conventional technology, such sensors suffer from reduced resolution of visible-light and infrared images due to the small number of pixels, and reduced sensitivity due to filters on visible-light pixels.
One example of a sensor that can capture visible light and infrared signals with a single sensor. In this sensor, visible light pixels and infrared light pixels are laid out in a two-dimensional array. At the top of the sensor is a dual band pass filter that passes a specific band of visible light and a specific band of infrared light. Visible pixels are fitted with filters to block specific bands of infrared light, and infrared pixels are fitted with filters to block visible light.
In this sensor, visible and infrared signals are captured simultaneously by replacing a part of visible pixels laid out in a two-dimensional array with infrared pixels. For example, three of the four pixel groups are used for visible light (R, G, B) detection and the remaining one is used for infrared (IR) detection. However, due to the above replacement, the number of visible light pixels becomes relatively small, resulting in degradation of the image quality of the visible light image. Also, because the number of infrared pixels is absolutely small, infrared images have poor resolution.
Furthermore, in this sensor, the infrared pixels and the visible pixels are placed adjacent to each other, so that infrared rays easily leak into the visible  pixels. In addition, when the shielding characteristics of the infrared shielding filter are insufficient, infrared rays leak into visible light pixels. Therefore, the problem of color mixing tends to arise.
Another example shows another example of a sensor that can capture visible light and infrared signals with a single sensor. In this sensor, a silicon photodiode layer for reading visible light signals and a photoelectric film layer for reading infrared signals are stacked.
In this example, a visible-light pixel color filter, which is an interference type that transmits a specific color signal through it, is used to suppress the mixing of infrared rays into the visible-light signal and improve color reproducibility. However, the pixels of the sensor are laid out in a two-dimensional array, and as in the previous example, only one of the four pixel groups is used for infrared (IR) detection, and thus the resolution of the infrared image is low.
Another aspect of this example is the use of a color filter, a pigment-type that passes specific color and infrared signals, that increases the resolution of the infrared image by detecting visible and infrared light in different layers at each pixel of the sensor. However, in this case, the infrared signal is mixed with the visible light signal, and color reproducibility is degraded.
SUMMARY
Problem to be solved by the invention
The objective of the invention is to solve the above problem in a conventional sensor capable of capturing visible light and infrared signals with a single sensor. These include low resolution of infrared images due to the small number of pixels, reduced sensitivity of visible-light images due to visible-light pixel color filters, and degraded color reproducibility due to the mixing of infrared light into visible-light pixels.
Means for Solving Problems
According to a first aspect, an embodiment of the present invention provides a sensor. The sensor includes a dual band pass filter, a first sensor  layer, and a second sensor layer in stacked order from an object side. The first sensor layer comprises a plurality of first pixels, and the second sensor layer comprises a plurality of second pixels. The sensor detects a first band of light passing through the dual band pass filter at the first sensor layer, and detects a second band of light passing through the dual band pass filter at the second sensor layer.
With reference to the first aspect, in one possible implementation, the first band of the dual band pass filter corresponds to visible light, and the second band of the dual band pass filter corresponds to infrared light.
With reference to the first aspect, in one possible implementation, the first band passes a specific band of visible light, and the second band passes a specific band of infrared light.
With reference to the first aspect, in one possible implementation, the second band of the dual band pass filter has its short wavelength end of transmission band for the infrared light located at greater than or equal to 1000 nm.
With reference to the first aspect, in one possible implementation, the plurality of first pixels in the first sensor layer are a plurality of photodiodes, and each of the photodiodes generates a signal charge according to visible light in the specific wavelength band.
With reference to the first aspect, in one possible implementation, the first sensor layer further comprises a color filter to pass through the specific wavelength band of visible light.
With reference to the first aspect, in one possible implementation, the first sensor layer further comprises an infrared light cut filter to block the specific band of infrared light.
With reference to the first aspect, in one possible implementation, the infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and a long wavelength end of the transmission band for visible light  in the first band of the dual band pass filter is located within the absorption band of the infrared cut filter.
With reference to the first aspect, in one possible implementation, the first sensor layer further comprises a plurality of microlenses, and each of the plurality of microlenses corresponds to one or more of corresponding first pixels of the plurality of first pixels.
With reference to the first aspect, in one possible implementation, the plurality of second pixels in the second sensor layer are a plurality of infrared pixels, and each of the infrared pixels generates a signal charge according to infrared light of a certain wavelength or greater.
With reference to the first aspect, in one possible implementation, each of the plurality of second pixels is connected to a readout circuit of the first sensor layer by a Cu-Cu coupling.
With reference to the first aspect, in one possible implementation, the second sensor layer further comprises an infrared pass filter to pass through infrared light of the certain wavelength or greater.
With reference to the first aspect, in one possible implementation, the second sensor layer comprises a photoelectric conversion film having the plurality of second pixels.
With reference to the first aspect, in one possible implementation, the photoelectric conversion film in the second sensor layer is made of quantum dots, an organic layer, a Ge-Si layer, a Si-layer, or an InGaAs layer.
With reference to the first aspect, in one possible implementation, the sensor acquires depth information by Time of Flight (TOF) by using the photoelectric conversion film in the second sensor layer.
According to a second aspect, an embodiment of the present invention provides a method of manufacturing a sensor. The sensor comprises a dual band pass filter, a first sensor layer, and a second sensor layer in stacked order  from an object side. The method comprises constructing the first sensor layer by laminating a color filter to pass through a specific wavelength band of visible light and a plurality of photodiodes on one silicon layer, constructing the second sensor layer with a photoelectric conversion film having a plurality of infrared pixels over another silicon layer, and connecting each of the plurality of infrared pixels to readout circuits of the first sensor layer by using a Cu-Cu coupling.
With reference to the second aspect, in one possible implementation, the second sensor layer further comprises an infrared pass filter laminated on the photoelectric conversion film to pass through infrared light of a specific wavelength or greater.
With reference to the second aspect, in one possible implementation, the method further comprises constructing a plurality of microlenses on the first sensor layer, and each of the plurality of microlenses corresponds to one or more of corresponding photodiodes of the plurality of photodiodes.
With reference to the second aspect, in one possible implementation, the dual band pass filter has a characteristic to pass through the specific wavelength band of visible light and to pass through infrared light of the specific wavelength or greater, and has its short wavelength end of transmission band for the infrared light located at greater or equal to 1000 nm.
With reference to the second aspect, in one possible implementation, the method further comprises laminating an infrared cut filter to block infrared light of a specific band on the first sensor layer. The infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and a long wavelength end of the transmission band for visible light in the dual band pass filter is located within the absorption band of the infrared cut filter.
BREIF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
In order to more clearly describe embodiments of the present invention, the accompanying drawings as required will be briefly described below. Obviously, in the following description, the accompanying drawings show only some embodiments of the present invention, and other drawings from these  accompanying drawings can be drawn by a skilled person in the art without creative effort.
FIG. 1 shows a cross-sectional view of the configuration of the sensor according to the first embodiment of the present invention.
FIG. 2 is a graph showing the characteristics of each filter used in the first embodiment.
FIG. 3 is a graph showing the characteristics of each pixel used in the first embodiment.
FIG. 4 is a schematic diagram showing the arrangement of pixels in the first embodiment.
FIG. 5 is a graph showing the resulting spectral sensitivity in the first embodiment.
FIG. 6 shows the transmission band of the dual band pass filter used in the second embodiment of the present invention.
FIG. 7 is a graph showing the resulting spectral sensitivity in the second embodiment.
FIG. 8 shows a cross-sectional view of the configuration of the sensor according to the third embodiment of the present invention.
FIG. 9 shows the transmission bands of the dual band pass filter and the infrared cut filter used in the third embodiment.
FIG. 10 is a graph showing the resulting spectral sensitivity in the third embodiment.
FIG. 11 shows a cross-sectional view of the configuration of the sensor according to the fourth embodiment of the present invention.
FIG. 12 shows a cross-sectional view of the configuration of the sensor according to the fifth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Hereafter, the embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a cross-sectional view of the configuration of a sensor 1 according to the first embodiment of the present invention. In the sensor 1 according to this embodiment, a dual band pass filter (DBPF) 10 is arranged on a sensor body, and a first sensor layer 11 and a second sensor layer 12 are  laminated on the sensor body. In Fig. 1, light enters the sensor body through a dual band pass filter 10 from above the figure, then, passes through the first sensor layer 11, and reaches the second sensor layer 12. A microlens (i.e. on chip lens, OCL) 111 is placed at the top of the sensor body to focus light.
A dual band pass filter 10 transmits light in specific bands of visible light and infrared light. The first sensor layer 11 comprises a color filter 112 and a silicon layer 113. The color filter 112 transmits a specific band of visible light. In the silicon layer 113, a plurality of photodiodes (PD) 114 are arrayed as pixels in an array to generate signal charges according to the specific band of light transmitted. The signal charge generated by the PD is converted into a voltage signal by a readout circuit 115.
The second sensor layer 12 comprises an infrared (IR) pass filter 121 and a photoelectric conversion film 122. The infrared pass filter 121 is a color filter that transmits infrared rays over a certain wavelength. The photoelectric conversion film 122 has infrared sensitivity, for example, a quantum dot film sensitive to short wave infrared region (SWIR) provided as SID 2021 made by STMicroelectronics may be used. In this embodiment, the infrared pass filter 121 and the photoelectric conversion film 122 are formed on another silicon layer 123 in the second sensor layer 12. Infrared pixels are arranged in an array configuration in the photoelectric conversion film 122, and each pixel is connected to the readout circuit 115 of the first sensor layer 11 by a Cu-Cu coupling 116, and its signal charge is converted into a voltage signal. The photoelectric conversion film 122 may be an organic layer, a Ge-Si layer, a Si layer, or an InGaAs layer in addition to the quantum dots.
FIG. 2 is a graph showing the characteristics of each filter used in the first embodiment. The thick solid line indicates the transmission band of the dual band pass filter 10, which includes the first band corresponding to visible light and the second band corresponding to infrared light. Three solid lines indicate transmission bands for each color (R, G, B) of the color filter 112, corresponding to blue (B) , green (G) , and red (R) from the left to the right. The thick dashed line indicates the transmission band of the infrared pass filter 121. The horizontal axis of the graph represents the wavelength of light in nanometers (nm) , and the vertical axis of the graph represents transmittance.
FIG. 3 is a graph showing the characteristics of each pixel used in the first embodiment. The thick solid line indicates the absorption characteristics of the photodiode (PD) 114 in the silicon layer 113 of the first sensor layer 11. The thick dashed line indicates the absorption characteristics of the photoelectric conversion film 122 on the silicon layer 123 in the second sensor layer 12. The horizontal axis of the graph represents the wavelength of light in nanometers (nm) similarly to FIG. 2, and the vertical axis of the graph represents absorptance.
FIG. 4 is a schematic diagram showing the arrangement of pixels in this embodiment. The first sensor layer 11 and the second sensor layer 12 are shown partially overlapping. The figure on the left side corresponds to the first sensor layer 11, and, for each color of visible light, photodiodes as visible light pixels are arranged as shown in the figure. The figure on the right side corresponds to the second sensor layer 12 placed below the first sensor layer 11, and the infrared pixels are arranged so as to correspond to the pixels (R, G, B) of the first sensor layer 11, so that infrared light can be detected at all the pixels. Thus, for the light incident on the sensor 1 according to this embodiment, the visible light (R, G, B) passing through the first band of the dual band pass filter 10 is detected in the first sensor layer 11, and then, for the light passing through the first sensor layer 11, the infrared light passing through the second band of the dual band pass filter 10 is detected in the corresponding pixel of the second sensor layer 12 placed below it. The microlens (OCL) 111 on the top of the sensor body can be arranged so that each of microlens corresponds to a corresponding pixel of the sensor body.
FIG. 5 is a graph showing the resulting spectral sensitivity in the first embodiment. In the graph, for visible light, there are blue (B) , green (G) , and red (R) peaks in order from the left side of the graph, and for infrared, there is a peak around the wavelength of 900 nm-1000 nm. This shows that each color component of visible light and infrared light can be detected using a single sensor 1. It should be noted that in the infrared band three lines for IR_G, IR_B, and IR_R are almost overlapping. However, in this embodiment, a small peak of sensitivity of visible light is found to overlap in the infrared band. This shows that in the 900 -1000 nm range, the infrared component is leaking into the visible light, which means that mixed color occurs somewhat in this range.
In the following the second embodiment to solve this problem is described.
FIG. 6 shows the transmission band of the dual band pass filter 10 used in the second embodiment. Compared with the dual band pass filter 10 used in the first embodiment shown in FIG. 2, the difference in the transmission band is that the shorter wavelength side in the second band for infrared light is set to be 1000 nm or greater, and for the longer wavelength bands about 100%of light is transmitted.
FIG. 7 is a graph showing the resulting spectral sensitivity in the second embodiment. In comparison with FIG. 5, it can be seen that the sensitivity of visible light is missing in the infrared band. That is, the infrared component does not leak into visible light, and the problem of color mixing is solved. In addition, the transmission band of the dual band pass filter 10 has been changed such that approximately 100%of light can be transmitted in the wavelength band of 1000 nm or greater, thereby expanding the detection range of infrared light.
FIG. 8 shows a cross-sectional view of the configuration of sensor 1 according to the third embodiment of the present invention. Compared with the first embodiment shown in Fig. 1, an infrared cut filter 130 is added above the color filter 112 in the first sensor layer 11. The infrared cut filter 130 is for blocking a specific band of infrared light.
FIG. 9 shows the transmission bands of the dual band pass filter 10 and the infrared cut filter 130 used in the third embodiment. Depending on configurations, characteristics of the dual band pass filter may have incident angle dependence, for example, if it is formed only with a multilayer reflective film. Specifically, the dual band pass filter 10 has an angular dependence of filter characteristics on incident light. In a case of the incident angle being 30 degrees, as compared with the characteristics when the incident angle is 0 degrees which is shown by the thick solid line in Fig. 9, the transmission band overall shifts to the shorter wavelength side as shown by the thick broken line. On the other hand, because the infrared cut filter 130 is formed using an absorber, the filter characteristics have no angular dependence on incident light.
In the third embodiment, as shown in FIG. 9, the long wavelength end of the transmission band of the first band corresponding to the visible light (R, G, B) of the dual band pass filter 10 is arranged so as to be within the absorption band of the infrared cut filter 130.
FIG. 10 is a graph showing the resulting spectral sensitivity in the third embodiment. The dashed line shows the characteristics of the case where the incident angle is 30 degrees, and it can be seen that the characteristics of the case where the incident angle is 0 degree shown by the solid line is almost overlapping. It should be noted that in the infrared band also characteristics of two cases are almost overlapping. By arranging the dual band pass filter 10 and the infrared-cut filter 130 in this way, it can be understood that the spectral sensitivity characteristics of RGB do not change for visible light pixels even if the dual band pass filter 10 has an angular dependence on the incident angle.
FIG. 11 shows a cross-sectional view of the configuration of the sensor 1 according to the fourth embodiment of the present invention. Compared with the first embodiment shown in Fig. 1, the infrared pixels in the photoelectric conversion film 122 of the second sensor layer 12 are connected to a readout circuit 240 formed in the silicon layer 123 of the second sensor layer 12, instead of the readout circuit 115 of the first sensor layer 11.
In the fourth embodiment, compared with the first embodiment, the Cu-Cu coupling 116 is not required and the process of manufacturing the sensor 1 can be simplified.
FIG. 12 shows a cross-sectional view of the configuration of the sensor 1 according to the fifth embodiment of the present invention. The fifth embodiment uses infrared pixels as a time-of-flight (TOF) sensor. In Fig. 12, for example, when the electric charge generated in the infrared pixel (irPD) of the Ge-Si layer, which is the photoelectric conversion film 122 of the second sensor layer 12, is transferred to the ST by an electric field formed between the ST (storage) region and the irPD, and is further distributed from the ST, by gates 1 and 2 (g1, g2) , to drains 1 and 2 (d1, d2) in a time-divided manner, the indirect TOF of a continuous waveform system can be obtained. In this way, in addition  to the detection of visible light and infrared light, depth information can also be acquired by the sensor.
The above description is an embodiment provided by this application, but is not intended to limit the present invention. Any modification, equivalent substitution, or improvement made without departing from the spirit and principles of the present invention should fall within the scope of protection of this application.
Description of Symbols
1 Sensor
10 Dual band pass filter
11 First sensor layer
12 Second sensor layer
111 Microlens
112 Color filter
113 Silicon layer
114 Photodiode
115 Readout circuit
121 Infrared pass filter
122 Photoelectric conversion film
123 Silicon layer
125 Readout circuit
130 Infrared cut filter
Figure PCTCN2022126881-appb-000001

Claims (15)

  1. The sensor according to claim 5,
    wherein the first sensor layer further comprises:
    a color filter to pass through the specific wavelength band of visible light.
  2. The sensor according to claim 6,
    wherein the first sensor layer further comprises:
    an infrared light cut filter to block a specific band of infrared light.
  3. The sensor according to claim 7,
    wherein the infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and
    wherein a long wavelength end of the transmission band for visible light in the first band of the dual band pass filter is located within the absorption band of the infrared cut filter.
  4. The sensor according to claim 1,
    wherein the first sensor layer further comprises:
    a plurality of microlenses, and
    wherein each of the plurality of microlenses corresponds to one or more of corresponding first pixels of the plurality of first pixels.
  5. The sensor according to claim 1,
    wherein the plurality of second pixels in the second sensor layer are a plurality of infrared pixels, and
    wherein each of the infrared pixels generates a signal charge according to infrared light of a certain wavelength or greater.
  6. The sensor according to claim 1,
    wherein each of the plurality of second pixels is connected to a readout circuit of the first sensor layer by a Cu-Cu coupling.
  7. The sensor according to claim 10,
    wherein the second sensor layer further comprises:
    an infrared pass filter to pass through infrared light of the certain wavelength or greater.
  8. The sensor according to claim 1,
    wherein the second sensor layer comprises a photoelectric conversion film having the plurality of second pixels.
  9. The sensor according to claim 13,
    wherein the photoelectric conversion film in the second sensor layer is made of quantum dots, an organic layer, a Ge-Si layer, a Si layer, or an InGaAs layer.
  10. The sensor according to claim 1,
    wherein the sensor acquires depth information by Time of Flight (TOF) by using the photoelectric conversion film in the second sensor layer.
  11. A method of manufacturing a sensor, wherein the sensor comprises a dual band pass filter, a first sensor layer, and a second sensor layer in stacked order from an object side, and wherein the method comprising:
    constructing the first sensor layer by laminating a color filter to pass through a specific wavelength band of visible light and a plurality of photodiodes on one silicon layer,
    constructing the second sensor layer with a photoelectric conversion film having a plurality of infrared pixels over another silicon layer, and
    connecting each of the plurality of infrared pixels to readout circuits of the first sensor layer by using a Cu-Cu coupling.
  12. The method according to claim 16,
    wherein the second sensor layer further comprises an infrared pass filter laminated on the photoelectric conversion film to pass through infrared light of a specific wavelength or greater.
  13. The method according to claim 16, further comprising:
    constructing a plurality of microlenses on the first sensor layer, and
    wherein each of the plurality of microlenses corresponds to one or more corresponding photodiodes of the plurality of photodiodes.
  14. The method according to claim 16,
    wherein the dual band pass filter has a characteristic to pass through the specific wavelength band of visible light and to pass through infrared light of the specific wavelength or greater, and has its short wavelength end of transmission band for the infrared light located at greater than or equal to 1000 nm.
  15. The method according to claim 16, wherein the method further comprising:
    laminating an infrared cut filter to block infrared light of a specific band on the first sensor layer,
    wherein the infrared cut filter has an absorption band in a range of 600 nm to 900 nm wavelength, and
    wherein a long wavelength end of the transmission band for visible light in the dual band pass filter is located within the absorption band of the infrared cut filter.
PCT/CN2022/126881 2022-10-24 2022-10-24 Stacked sensor for simultaneouly detecting visible light and infrared light WO2024086959A1 (en)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20070083300A (en) * 2006-02-16 2007-08-24 마루엘에스아이 주식회사 Light sensing device for sensing visible light and infrared light, and method for fabricating the same
US9184198B1 (en) * 2013-02-20 2015-11-10 Google Inc. Stacked image sensor with cascaded optical edge pass filters
US20180323232A1 (en) * 2016-01-15 2018-11-08 Towerjazz Panasonic Semiconductor Co., Ltd. Solid-state imaging device
US20190189696A1 (en) * 2016-05-20 2019-06-20 Sony Corporation Solid-state imaging apparatus and electronic apparatus
CN110970451A (en) * 2018-09-28 2020-04-07 台湾积体电路制造股份有限公司 Image sensor, integrated circuit and method of forming image sensor
CN111094915A (en) * 2017-09-22 2020-05-01 高通股份有限公司 Solid state image sensor with on-chip filter and extended spectral response
CN111477692A (en) * 2019-01-22 2020-07-31 三星电子株式会社 Photodiode, organic sensor, and electronic device
CN112582437A (en) * 2019-09-30 2021-03-30 台湾积体电路制造股份有限公司 Image sensor and method for forming the same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20070083300A (en) * 2006-02-16 2007-08-24 마루엘에스아이 주식회사 Light sensing device for sensing visible light and infrared light, and method for fabricating the same
US9184198B1 (en) * 2013-02-20 2015-11-10 Google Inc. Stacked image sensor with cascaded optical edge pass filters
US20180323232A1 (en) * 2016-01-15 2018-11-08 Towerjazz Panasonic Semiconductor Co., Ltd. Solid-state imaging device
US20190189696A1 (en) * 2016-05-20 2019-06-20 Sony Corporation Solid-state imaging apparatus and electronic apparatus
CN111094915A (en) * 2017-09-22 2020-05-01 高通股份有限公司 Solid state image sensor with on-chip filter and extended spectral response
CN110970451A (en) * 2018-09-28 2020-04-07 台湾积体电路制造股份有限公司 Image sensor, integrated circuit and method of forming image sensor
CN111477692A (en) * 2019-01-22 2020-07-31 三星电子株式会社 Photodiode, organic sensor, and electronic device
CN112582437A (en) * 2019-09-30 2021-03-30 台湾积体电路制造股份有限公司 Image sensor and method for forming the same

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