JP2021150615A - Sensor device and manufacturing method thereof - Google Patents

Abstract

To provide a sensor device that can implement a resonator in a suitable manner, and a manufacturing method thereof.SOLUTION: A sensor device according to the present disclosure comprises: a photoelectric conversion part; a Fabry-Perot resonator that is provided on the photoelectric conversion part; and a filter layer that is provided on the Fabry-Perot resonator, or between the Fabry-Perot resonator and the photoelectric conversion part.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a sensor device and a method for manufacturing the same.

In multi-spectral using a Fabry Perot resonator, it is conceivable to change the peak wavelength of light by changing the resonator length (thickness of the resonator) for each pixel. In this case, since it is necessary to change the resonator length for each pixel, the process of manufacturing the resonator becomes difficult.

On the other hand, it is conceivable to change the effective refractive index of the resonator and change the peak wavelength of light by using a microfabricated structure containing two or more kinds of materials having different refractive indexes. This makes it possible to change the peak wavelength of light without changing the resonator length for each pixel. However, for example, when a microfabricated structure including a silicon oxide portion and a silicon nitride portion is used, the change in the effective refractive index is small, so that the change in the peak wavelength from visible light to near-infrared light is at most about 100 nm. .. Further, even when a microfabricated structure including a titanium nitride portion having a high refractive index is used instead of the silicon nitride portion described above, the change in peak wavelength is at most about 150 nm.

JP-A-2007-103401 Japanese Unexamined Patent Publication No. 2006-229078 JP-A-2010-251489 Japanese Unexamined Patent Publication No. 2018-26378 Japanese Unexamined Patent Publication No. 2011-9673 Japanese Patent No. 5428206 Japanese Unexamined Patent Publication No. 2015-88847

Since the Fabripero resonator reflects unnecessary light, the surface of the Fabricero resonator has high reflectance. Therefore, when the fabric pero resonator is placed inside the image sensor, when strong light such as sunlight is incident on the image sensor, flare or the like is likely to occur due to the reflected light of the fabric pero resonator, and the image may be deteriorated at the time of imaging. be. Furthermore, the peak wavelength of the spectroscopic spectrum obtained by the fabric pero resonator may shift to the short wavelength side due to the change in the incident angle of the main ray depending on the image height.

Therefore, in multi-spectroscopy using a Fabry Pero resonator, the peak wavelength of light is changed by the resonator, the half width of the obtained light is narrowed in a wide wavelength range, and sensors equipped with the resonator are mass-produced. It is required to make it easier. Further, it is required to suppress problems in imaging such as flare and to suppress changes in spectral wavelength due to image height.

Therefore, the present disclosure provides a sensor device in which a resonator can be mounted in a suitable manner, and a method for manufacturing the same.

The sensor device on the first side of the present disclosure includes a photoelectric conversion unit, a fabric pero resonator provided on the photoelectric conversion unit, and a fabric pero resonator or between the fabric pero resonator and the photoelectric conversion unit. It is provided with a provided filter layer. As a result, the fabric pero resonator can be mounted on the sensor device in a suitable manner, for example, the defects of the fabric pero resonator can be compensated for by the filter layer.

The sensor device on the second side of the present disclosure includes a photoelectric conversion unit, a resonator provided on the photoelectric conversion unit and including a metamaterial layer, and the resonator or the resonator and the photoelectric conversion unit. A filter layer provided between the metamaterial layers is provided, and the metamaterial layer is formed of a first portion formed of the first material and a second material different from the first material, and is provided in the first portion. Includes a plurality of second parts. This makes it possible to mount the resonator in the sensor device in a suitable manner, for example, the defect of the resonator can be compensated for by the filter layer.

Further, in the second aspect, one of the first and second materials may be an insulating material containing silicon, and the other of the first and second materials may be an insulating material containing silicon or a semiconductor material. As a result, for example, the metamaterial layer can be formed of a silicon-based material, and the effective refractive index of the resonator can be increased by changing the volume ratio of the first portion and the second portion formed of different silicon-based materials. It will be possible to change.

Further, the sensor device on the second side surface may further include a semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer. This makes it possible, for example, to cover the upper or lower surface of the metamaterial layer with a non-insulating material.

Further, in the second aspect, a semiconductor other than the semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer is located between the metamaterial layer and the substrate including the metamaterial layer and the photoelectric conversion unit. The layer may not be provided. This makes it possible, for example, not to dispose a non-insulating material in the laminated film other than the semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer.

Further, in the second aspect, the semiconductor layer may be a silicon layer. This makes it possible to easily form, for example, a semiconductor layer.

Further, on the second side surface, the resonator may include the metamaterial layer and an insulating film in contact with the upper surface or the lower surface of the metamaterial layer. This allows, for example, the upper or lower surface of the metamaterial layer to be separated from the non-insulating material.

Further, on the second side surface, the insulating film may be formed of the first or second material. This makes it possible to easily form an insulating film with the same material as the metamaterial layer, for example.

Further, on the second side surface, the resonator is provided in a laminated film provided on the photoelectric conversion part, and the filter layer is on the laminated film or in the laminated film and the photoelectric conversion part. The laminated film is provided between the first layer provided on the photoelectric conversion unit, the resonator provided on the first layer, and the resonator provided on the resonator. It may include a second layer. This makes it possible, for example, to adjust the performance of the resonator with the first layer and the second layer.

Further, in this second aspect, at least one of the first and second layers may include one or more insulating films and / or one or more semiconductor layers. This makes it possible, for example, to adjust the performance of the resonator with an insulating film or a semiconductor layer.

Further, in this second aspect, the refractive index of the second material may be different from the refractive index of the first material. This makes it possible to change the effective refractive index of the resonator, for example, by changing the volume ratio of the first portion and the second portion.

Further, in the second aspect, the peak wavelength of the light transmitted through the resonator may change according to the effective refractive index of the resonator. This makes it possible, for example, to adjust the peak wavelength of the light transmitted through the resonator by the effective refractive index of the resonator.

Further, in this second aspect, the effective refractive index of the resonator may be set based on the image height of the sensor device. This makes it possible to suppress short wavelength shifts, for example.

Further, the sensor device on the second side surface may further include a lens provided on the resonator, and the planar shape of the lens may be asymmetric with respect to the center of the lens. This makes it possible to suppress short wavelength shifts, for example.

Further, in the second aspect, the resonator may be provided on a compound semiconductor substrate including the photoelectric conversion unit. This makes it possible to realize, for example, a sensor device having better characteristics than when a silicon substrate is used.

Further, in the second aspect, the compound semiconductor substrate includes an InGaAs (indium gallium arsenide) layer and an InP (indium phosphide) layer provided on the InGaAs layer, and the resonator is the InP. It may be provided on the layer. This makes it possible to realize, for example, a sensor device having better characteristics than when a silicon substrate is used.

Further, in the second aspect, the resonator length of the resonator may be λ / n or more (λ represents the peak wavelength of the light output from the resonator in vacuum, and n is the resonance. Represents the effective refractive index of the vessel). This enables, for example, spectroscopy over a wide wavelength area.

Further, in the second aspect, the resonator length of the resonator may be 700 nm / n or more (n represents the effective refractive index of the resonator). This enables, for example, spectroscopy over a wide wavelength area.

Further, the sensor device on the second side surface includes the first portion formed of the first material and the plurality of second portions formed of the second material and provided in the first portion. The resonator including the metamaterial layer, a second portion formed of the second material, and a plurality of first portions formed of the first material and provided in the second portion. A second metamaterial layer including, and a second resonator including. This makes it possible, for example, to change the volume ratio between the first portion and the second portion in a wider range.

Further, in the second aspect, the sensor device may reduce the number of modes of light by transmitting multimode light through the filter layer and the resonator. This makes it possible, for example, to selectively inject light in a predetermined mode into the photoelectric conversion unit.

Further, in this second aspect, the sensor device may convert the multi-mode spectroscopy into a single-mode spectroscopy by signal processing. This makes it possible to obtain a single-mode spectroscopic spectrum even when the spectroscopic spectrum obtained by the resonator is in multiple modes, for example.

Further, in the second aspect, the sensor device transmits multi-mode light through the filter layer and the resonator to generate single-mode light having a peak wavelength in the wavelength range of near-infrared light. It may be generated. As a result, for example, near-infrared light, which is light with less noise of sunlight, can be selectively incident on the photoelectric conversion unit.

Further, in the second aspect, the sensor device may be a solid-state image pickup device including a pixel array region having a plurality of pixels. This makes it possible, for example, to apply an excellent resonator to imaging.

Further, in the second aspect, the pixel array region may have a periodic array in which n × n (n is an integer of 2 or more) pixels as a unit. This makes it possible to realize, for example, a solid-state image sensor suitable for multi-spectroscopy.

In the method of manufacturing the sensor device on the third aspect of the present disclosure, a photoelectric conversion unit is formed, a fabric pero resonator is formed on the photoelectric conversion unit, and the fabric pero resonator or the fabric pero resonator and the photoelectric conversion unit are formed. Includes forming a filter layer between and. As a result, the fabric pero resonator can be mounted on the sensor device in a suitable manner, for example, the defects of the fabric pero resonator can be compensated for by the filter layer.

In the method of manufacturing the sensor device of the fourth aspect of the present disclosure, a photoelectric conversion unit is formed, a resonator including a metamaterial layer is formed on the photoelectric conversion unit, and the resonator or the resonator and the resonator are formed. The metamaterial layer is formed of a first portion formed of a first material and a second material different from the first material, and includes forming a filter layer between the photoelectric conversion unit and the metamaterial layer. Includes a plurality of second portions provided within one portion. This makes it possible to mount the resonator in the sensor device in a suitable manner, for example, the defect of the resonator can be compensated for by the filter layer.

Further, in the fourth aspect, the metamaterial layer forms a first portion formed of the first material, and the plurality of second portions formed of the second material in the first portion. It may be formed by embedding a portion. This makes it possible, for example, to easily form a metamaterial layer by a general method of a semiconductor manufacturing process.

It is a block diagram which shows the structure of the solid-state image sensor of 1st Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 1st Embodiment. It is another cross-sectional view which shows the structure of the solid-state image sensor of 1st Embodiment. It is a perspective view which shows the structure of the resonator of 1st Embodiment. It is a top view which shows the structure of the resonator of 1st Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is a flowchart which shows the operation of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 1st Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 2nd Embodiment. It is a schematic diagram which shows the structure of the solid-state image sensor of 2nd Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 2nd Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 2nd Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 2nd Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 3rd Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 3rd Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 3rd Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 3rd Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 3rd Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 4th Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 4th Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 4th Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 4th Embodiment. It is a flowchart which shows the operation of the solid-state image sensor of 4th Embodiment. It is a schematic diagram for demonstrating the structure of the solid-state image sensor of 5th Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 5th Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 5th Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 5th Embodiment. It is another graph for demonstrating the characteristic of the solid-state image sensor of 5th Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 6th Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 6th Embodiment. It is a top view for demonstrating the structure of the resonator of 6th Embodiment. It is a top view for demonstrating the structure of the solid-state image sensor of 7th Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 7th Embodiment. It is a top view and the cross-sectional view for demonstrating the structure of the modification of the solid-state image pickup apparatus of 7th Embodiment. It is sectional drawing (1/2) which shows the manufacturing method of the solid-state image sensor of 8th Embodiment. It is sectional drawing (2/2) which shows the manufacturing method of the solid-state image sensor of 8th Embodiment. It is sectional drawing (1/2) which shows the detail of the manufacturing method of the solid-state image sensor of 8th Embodiment. It is sectional drawing (2/2) which shows the detail of the manufacturing method of the solid-state image sensor of 8th Embodiment. It is sectional drawing which shows the structure of the solid-state image sensor of 9th Embodiment. It is a perspective view which shows the structure of the resonator of 9th Embodiment. It is a graph for demonstrating the characteristic of the solid-state image sensor of 9th Embodiment. It is a graph for demonstrating the operation of the solid-state image sensor of the tenth embodiment. It is a graph for demonstrating the operation of the solid-state image sensor of 11th Embodiment. It is a block diagram which shows the structural example of an electronic device. It is a block diagram which shows the configuration example of a mobile body control system. It is a top view which shows the specific example of the setting position of the image pickup part of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a block diagram showing a configuration of a solid-state image sensor according to the first embodiment.

The solid-state image sensor of FIG. 1 is a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, which includes a pixel array region 2 having a plurality of pixels 1, a control circuit 3, a vertical drive circuit 4, and a plurality of column signal processing. It includes a circuit 5, a horizontal drive circuit 6, an output circuit 7, a plurality of vertical signal lines 8, and a horizontal signal line 9. The solid-state image sensor of FIG. 1 is an example of the sensor device of the present disclosure.

Each pixel 1 includes a photodiode that functions as a photoelectric conversion unit, and a plurality of pixel transistors. Examples of pixel transistors are MOS transistors such as transfer transistors, reset transistors, amplification transistors, and selection transistors.

The pixel array region 2 has a plurality of pixels 1 arranged in a two-dimensional array. The pixel array region 2 is an effective pixel region that receives light and performs photoelectric conversion, amplifies and outputs the signal charge generated by the photoelectric conversion, and black for outputting optical black that serves as a reference for the black level. It includes a reference pixel area (not shown). Generally, the black reference pixel region is arranged on the outer peripheral portion of the effective pixel region.

The control circuit 3 generates various signals that serve as reference for the operation of the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, and the like based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock. The signal generated by the control circuit 3 is, for example, a clock signal or a control signal, and is input to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, and the like.

The vertical drive circuit 4 includes, for example, a shift register, and scans each pixel 1 in the pixel array region 2 in a row unit in the vertical direction. The vertical drive circuit 4 further supplies a pixel signal based on the signal charge generated by each pixel 1 to the column signal processing circuit 5 through the vertical signal line 8.

The column signal processing circuit 5 is arranged for each column of the pixel 1 in the pixel array area 2, for example, and performs signal processing of the signal output from the pixel 1 for one row based on the signal from the black reference pixel area. Do it for each row. Examples of this signal processing are noise removal and signal amplification.

The horizontal drive circuit 6 includes, for example, a shift register, and supplies pixel signals from each column signal processing circuit 5 to the horizontal signal line 9.

The output circuit 7 performs signal processing on the signal supplied from each column signal processing circuit 5 through the horizontal signal line 9, and outputs the processed signal.

FIG. 2 is a cross-sectional view showing the structure of the solid-state image sensor of the first embodiment. FIG. 2 shows a vertical cross section of the pixel array region 2 of FIG.

The solid-state image sensor of the present embodiment includes a support substrate 11, a plurality of wiring layers 12, 13, 14 and an interlayer insulating film 15, and a gate electrode 16 and a gate insulating film 17 included in each transfer transistor Tr1. There is.

The solid-state image sensor of the present embodiment further includes a substrate 21, a plurality of photoelectric conversion units 22 in the substrate 21, and a p-type semiconductor region 23, an n-type semiconductor region 24, and a p-type semiconductor included in each photoelectric conversion unit 22. A region 25, a pixel separation layer 26 in the substrate 21, a p-well layer 27, and a plurality of floating diffusion portions 28 are provided.

The solid-state image sensor of the present embodiment further includes a groove 31, an element separation unit 32 provided in the groove 31, a fixed charge film (a film having a negative fixed charge) 33 and an insulating film included in the element separation unit 32. 34, a light-shielding film 35, a flattening film 36, a laminated film 37 provided above each photoelectric conversion unit 22, a color filter layer 38, and an on-chip lens 39 are provided.

FIG. 2 shows the X-axis, Y-axis, and Z-axis that are perpendicular to each other. The X and Y directions correspond to the horizontal direction (horizontal direction), and the Z direction corresponds to the vertical direction (vertical direction). Further, the + Z direction corresponds to the upward direction, and the −Z direction corresponds to the downward direction. The −Z direction may or may not exactly coincide with the direction of gravity.

The substrate 21 is, for example, a semiconductor substrate such as a silicon (Si) substrate. In FIG. 2, the surface of the substrate 21 in the −Z direction is the front surface of the substrate 21, and the surface of the substrate 21 in the Z direction is the surface of the back side (back surface) of the substrate 21. Since the solid-state image sensor of this embodiment is a back-illuminated type, the color filter layer 38 and the on-chip lens 39 are provided on the back side of the substrate 21, and are located above the substrate 21 in FIG. The back surface of the substrate 21 is the light incident surface of the substrate 21. On the other hand, the wiring layers 12 to 14 are provided on the front side of the substrate 21, and are located below the substrate 21 in FIG.

The photoelectric conversion unit 22 is provided in the substrate 21 for each pixel 1. FIG. 2 illustrates three photoelectric conversion units 22 for three pixels 1. Each photoelectric conversion unit 22 includes a p-type semiconductor region 23, an n-type semiconductor region 24, and a p-type semiconductor region 25, which are sequentially formed in the substrate 21 from the front side to the back side of the substrate 21. In the photoelectric conversion unit 22, a main photodiode is realized by a pn junction between the p-type semiconductor region 23 and the n-type semiconductor region 24 and a pn junction between the n-type semiconductor region 24 and the p-type semiconductor region 25. The photodiode converts light into a charge. The photoelectric conversion unit 22 receives the light incident on the on-chip lens 39 through the color filter layer 38, generates a signal charge according to the amount of the received light, and transfers the generated signal charge to the n-type semiconductor region 24. accumulate.

The pixel separation layer 26 is a p-type semiconductor region provided between photoelectric conversion units 22 adjacent to each other. The p-well layer 27 is a p-type semiconductor region provided on the front side of the substrate 21 with respect to the pixel separation layer 26. The floating diffusion portion 28 is an n + type semiconductor region provided on the front side of the substrate 21 with respect to the p-well layer 27. The floating diffusion portion 28 is formed by injecting n-type impurities into the p-well layer 27 at a high concentration.

The groove 31 has a shape extending from the back surface of the substrate 21 in the depth direction (−Z direction), and is provided between the photoelectric conversion units 22 adjacent to each other, similarly to the pixel separation layer 26. The groove 31 is formed by forming a recess in the pixel separation layer 26 by etching.

The element separation unit 32 includes a fixed charge film 33 and an insulating film 34, which are sequentially formed in the groove 31. The fixed charge film 33 is formed on the side surface and the bottom surface of the groove 31. The insulating film 34 is embedded in the groove 31 via the fixed charge film 33.

The fixed charge film 33 is a film having a negative fixed charge, and is a material for the element separating portion 32. Generally, in a solid-state image sensor, electric charges may be generated from minute defects existing at the interface of the substrate 21 even in a state where there is no incident light and no signal charges. This charge causes noise called dark current. However, a film having a negative fixed charge has an effect of suppressing the generation of such a dark current. Therefore, according to the present embodiment, the dark current can be reduced by the fixed charge film 33. The fixed charge film 33 of the present embodiment is formed on the entire back surface of the substrate 21, and is arranged not only in the element separation unit 32 but also on the photoelectric conversion unit 22. The fixed charge film 33 is, for example, an oxide film or a nitride film containing hafnium (Hf), aluminum (Al), zirconium (Zr), tantalum (Ta), or titanium (Ti).

The insulating film 34 is used as a material for the element separating portion 32 together with the fixed charge film 33. The insulating film 34 is preferably formed of a material having a refractive index different from that of the fixed charge film 33. Examples of such an insulating film 34 are a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a resin film, and the like. Further, the insulating film 34 may be a film having no positive fixed charge or a film having a small positive fixed charge. The insulating film 34 of the present embodiment is formed on the entire back surface of the substrate 21, and is arranged not only in the element separation unit 32 but also on the photoelectric conversion unit 22.

The light-shielding film 35 is formed in a predetermined region on the insulating film 34 formed on the back surface of the substrate 21, and has an effect of blocking light from the on-chip lens 39. In the pixel array region 2, the light-shielding film 35 is formed in a mesh shape so that the photoelectric conversion unit 22 opens with respect to the on-chip lens 39, and specifically, is formed on the element separation unit 32. .. The light-shielding film 35 is a film formed of a material that blocks light, and is, for example, a metal film containing tungsten (W), aluminum (Al), or copper (Cu).

The flattening film 36 is formed on the entire surface of the insulating film 34 so as to cover the light-shielding film 35, whereby the surface on the back surface of the substrate 21 is flat. The flattening film 36 is, for example, an organic film such as a resin film.

The laminated film 37 is formed on the flattening film 36, and includes, for example, a silicon oxide film, a silicon nitride film, a silicon layer, and the like. The laminated film 37 of the present embodiment further includes a resonator 51 having a different structure for each pixel 1, as will be described later. Details of the laminated film 37 will be described later.

The color filter layer 38 is formed on the laminated film 37 for each pixel 1, and is also called an OCCF (on-chip color filter). For example, the color filter layers 38 for red (R), green (G), and blue (B) are arranged above the photoelectric conversion unit 22 of the red, green, and blue pixels 1, respectively. Alternatively, the color filter layers 38 for yellow (Y), magenta (M), and cyan (C) may be arranged above the photoelectric conversion unit 22 of the yellow, magenta, and cyan pixels 1, respectively. Further, these color filter layers 38 may include a color filter layer 38 for infrared light above the photoelectric conversion unit 22 of the infrared light (IR) pixel 1. Each color filter layer 38 has a property that light of a predetermined wavelength can or cannot be transmitted, and the light transmitted through each color filter layer 38 passes through the laminated film 37, the insulating film 34, and the fixed charge film 33. It is incident on the photoelectric conversion unit 22. The color filter layer 38 may be arranged between the laminated film 37 and the flattening film 36 instead of being arranged between the laminated film 37 and the on-chip lens 39. That is, the color filter layer 38 may be arranged under the laminated film 37 instead of being arranged on the laminated film 37.

The on-chip lens 39 is formed on the color filter layer 38 for each pixel 1. Each on-chip lens 39 has a property of condensing incident light, and the light collected by each on-chip lens 39 is incident on the photoelectric conversion unit 22 via the corresponding color filter layer 38 or the like. do.

The support substrate 11 is provided on the front side of the substrate 21 via an interlayer insulating film 15 to ensure the strength of the substrate 21. The support substrate 11 is, for example, a semiconductor substrate such as a silicon substrate.

The wiring layers 12 to 14 are provided in the interlayer insulating film 15 provided on the front side of the substrate 21 to form a multilayer wiring structure. The multi-layer wiring structure of the present embodiment includes three wiring layers 12 to 14, but may include four or more wiring layers. Each of the wiring layers 12 to 14 includes various wirings, and a pixel transistor such as the transfer transistor Tr1 is driven by using these wirings. The wiring layers 12 to 14 are metal layers containing, for example, tungsten, aluminum, or copper. The interlayer insulating film 15 is, for example, an insulating film containing a silicon oxide film or the like.

The gate electrode 16 of each transfer transistor Tr1 is provided under the p-well layer 27 between the p-type semiconductor region 23 and the stray diffusion portion 28 via a gate insulating film 17. Each transfer transistor Tr1 can transfer the signal charge in the photoelectric conversion unit 22 to the floating diffusion unit 28. The gate electrode 16 and the gate insulating film 17 are provided in the interlayer insulating film 15.

In the solid-state image sensor of the present embodiment, light is irradiated from the back side of the substrate 21, and the light is incident on the on-chip lens 39. The light incident on the on-chip lens 39 is collected by the on-chip lens 39 and passes through the color filter layer 38, the laminated film 37, the flattening film 36, the insulating film 34, and the fixed charge film 33 to the photoelectric conversion unit 22. Incident. The photoelectric conversion unit 22 converts this light into an electric charge by photoelectric conversion to generate a signal charge. The signal charge is output as a pixel signal via the vertical signal line 8 in the wiring layers 12 to 14 provided on the front side of the substrate 21.

FIG. 3 is another cross-sectional view showing the structure of the solid-state image sensor of the first embodiment.

FIG. 3 shows a substrate 21, a laminated film 37, and a color filter layer 38 included in one pixel 1. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 3, the laminated film 37 of the present embodiment includes a silicon oxide film (SiO ₂ film) 41, a silicon nitride film (SiN film (Si ₃ N ₄ film)) 42, which are sequentially formed on the substrate 21. It includes a silicon oxide film 41, a polysilicon layer (poly-Si layer) 43, a metamaterial layer 44, a polysilicon layer 43, and a silicon oxide film 41. The metamaterial layer 44 functions as a resonator 51. The laminated film 37 of the present embodiment includes the resonator 51 to form a refractive index-modulated fabric-perot resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 3, for example. The silicon oxide film 41, the silicon nitride film 42, the silicon oxide film 41, and the polysilicon layer 43 under the resonator 51 are examples of the first layer of the present disclosure, and the polysilicon layer 43 and the silicon oxide on the resonator 51 The film 41 is an example of the second layer of the present disclosure. QE shown in FIG. 3 is an abbreviation for Quantum Efficiency. The resonator 51 is also called a cavity.

FIG. 4 is a perspective view showing the structure of the resonator 51 (metamaterial layer 44) of the first embodiment.

As shown in FIG. 4, the metamaterial layer 44 of the present embodiment is formed of a silicon nitride portion 42a formed of a silicon nitride film 42 and a silicon oxide film 41, and is provided in the silicon nitride portion 42a. It contains a plurality of silicon oxide portions 41a. The silicon nitride portion 42a has a generally quadrangular plate-like shape. On the other hand, each silicon oxide portion 41a has a columnar shape extending in the Z direction and penetrates the silicon nitride portion 42a. The silicon nitride portion 42a is an example of the first portion formed of the first material, and the silicon oxide portion 41a is an example of the plurality of second portions formed of the second material.

The silicon oxide portion 41a and the silicon nitride portion 42a have different refractive indexes. Specifically, the refractive index of the silicon nitride portion 42a is higher than the refractive index of the silicon oxide portion 41a. Therefore, the effective refractive index of the resonator 51 depends on the volume ratio of the silicon oxide portion 41a and the silicon nitride portion 42a in the metamaterial layer 44. Therefore, in the present embodiment, the effective refractive index of the resonator 51 can be changed for each pixel by changing the volume ratio of the silicon oxide portion 41a and the silicon nitride portion 42a for each pixel 1. As a result, the peak wavelength of the light output from the resonator 51 (that is, transmitted through the resonator 51) can be changed by changing the effective refractive index without changing the resonator length of the resonator 51. It will be possible.

The metamaterial layer 44 can be formed in various modes by selecting two or more kinds of materials having different refractive indexes and forming a fine structure with these materials. For example, the metamaterial layer 44 may be formed of silicon oxide and amorphous silicon, as will be described later. Further, the metamaterial layer 44 may be formed of silicon oxide and titanium oxide. The metamaterial layer 44 of the present embodiment is realized by a fine structure of 1/2 or less of the peak wavelength described above.

FIG. 5 is a plan view showing the structure of the resonator 51 (metamaterial layer 44) of the first embodiment.

FIG. 5 shows a metamaterial layer 44 of 4 × 4 pixels 1. In FIG. 5, the volume ratio of the silicon oxide portion 41a and the silicon nitride portion 42a is different for each metamaterial layer 44 (for each pixel 1). Further, FIG. 5 shows not only the metamaterial layer 44 in which the plurality of silicon oxide portions 41a are provided in the silicon nitride portion 42a, but also the metamaterial layer 44 in which the plurality of silicon nitride portions 42a are provided in the silicon oxide portion 41a. Shown. The latter metamaterial layer 44 (resonator 51) is an example of the second metamaterial layer (second resonator) of the present disclosure.

As described above, in the solid-state imaging device of the present embodiment, the metamaterial layer 44 in which the plurality of silicon oxide portions 41a are provided in the silicon nitride portion 42a and the plurality of silicon nitride portions 42a are provided in the silicon oxide portion 41a. It is provided with a metamaterial layer 44. As a result, the volume ratio of the silicon oxide portion 41a and the silicon nitride portion 42a can be changed in a wider range, and the effective refractive index of the resonator 51 can be changed in a wider range. As shown in FIG. 5, the solid-state image sensor of the present embodiment may further include a metamaterial layer 44 containing only the silicon oxide portion 41a and a metamaterial layer 44 containing only the silicon nitride portion 42a.

Next, with reference to FIGS. 3 to 5, further details of the resonator 51 and the like of the present embodiment will be described.

In FIG. 3, a polysilicon layer 43 is provided under the metamaterial layer 44, and the polysilicon layer 43 is in contact with the lower surface of the metamaterial layer 44. Therefore, the lower surface of the metamaterial layer 44 is separated from the silicon oxide film 41 and the like below the metamaterial layer 44. For example, when a transparent material (for example, silicon oxide film 41) is in contact with the lower surface of the metamaterial layer 44, this transparent material becomes a part of the resonator 51 together with the metamaterial layer 44. According to the present embodiment, the thickness of the resonator 51 can be reduced by contacting the polysilicon layer 43 with the lower surface of the metamaterial layer 44.

In FIG. 3, a polysilicon layer 43 is further provided on the metamaterial layer 44, and the polysilicon layer 43 is in contact with the upper surface of the metamaterial layer 44. Therefore, the upper surface of the metamaterial layer 44 is separated from the silicon oxide film 41 or the like above the metamaterial layer 44. For example, when a transparent material (for example, silicon oxide film 41) is in contact with the upper surface of the metamaterial layer 44, this transparent material becomes a part of the resonator 51 together with the metamaterial layer 44. According to the present embodiment, the thickness of the resonator 51 can be reduced by contacting the polysilicon layer 43 with the upper surface of the metamaterial layer 44.

In the present embodiment, semiconductor layers other than the above-mentioned two polysilicon layers 43 are provided between the metamaterial layer 44 and the color filter layer 38 and between the metamaterial layer 44 and the substrate 21. No. Therefore, the laminated film 37 of the present embodiment is entirely formed of an insulating film except for these polysilicon layers 43. On the other hand, an example of the laminated film 37 including a semiconductor layer other than these polysilicon layers 43 will be described later.

The metamaterial layer 44 shown in FIG. 4 includes a silicon nitride portion 42a having a high refractive index and a plurality of silicon oxide portions 41a having a low refractive index. As a result, the resonator 51 including the metamaterial layer 44 is realized.

The shape of each silicon oxide portion 41a in FIG. 4 is, for example, a cylinder. In the present embodiment, the diameter of this cylindrical circle is set to be smaller than the order of the peak wavelength of the light output from the resonator 51. That is, the silicon oxide portion 41a is microfabricated. This makes it possible to realize the resonator 51 having suitable characteristics.

FIG. 5 shows a metamaterial layer 44 (resonator 51) of 4 × 4 pixels 1. In the present embodiment, the resonator lengths of these resonators 51 are all set to be the same. The reason is that the peak wavelength of the light output from the resonator 51 can be changed by changing the effective refractive index without changing the resonator length of the resonator 51. Not changing the resonator length of the resonator 51 has an advantage that, for example, the resonator 51 can be easily manufactured.

FIG. 6 is a graph for explaining the characteristics of the solid-state image sensor of the first embodiment. FIG. 7 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment. FIG. 8 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment.

FIG. 6 shows an example of a spectrum of light transmitted through the laminated film 37. The horizontal axis represents the wavelength of this light, and the vertical axis represents the transmittance of this light at each wavelength. FIG. 7 shows another example of the spectrum of light transmitted through the laminated film 37, where the horizontal axis represents the wavelength of this light and the vertical axis represents the quantum efficiency of this light at each wavelength. FIG. 8 shows another example of the spectrum of light transmitted through the laminated film 37, where the horizontal axis represents the wavelength of this light and the vertical axis represents the quantum efficiency of this light at each wavelength.

The resonator length of the resonator 51 of the present embodiment is set to, for example, λ / n or more. λ represents the peak wavelength of the light passing through the resonator 51 in a vacuum. n represents the effective refractive index of the resonator 51. In the present embodiment, for example, the target value λ ₀ of this peak wavelength is used as the value of λ. It is desirable that the resonator length of the resonator 51 of the present embodiment is set to, for example, 700 nm / n or more.

In the present embodiment, by setting the resonator length to λ / n or more, the interval between the peak wavelength of one mode and the peak wavelength of the next mode becomes narrow. This is shown by the FSR (Free Spectal Range) of FIG. As a result, as shown in FIG. 7, for example, spectroscopy in a wide wavelength area becomes possible.

However, in this case, one spectral spectrum becomes multimode (multimode) and includes a large number of peaks (FIG. 7). Therefore, in the present embodiment, a layer having wavelength selectivity such as the color filter layer 38 is arranged on the laminated film 37. As a result, it is possible to reduce the number of modes (wavelength range) of the light incident on the laminated film 37, and it is possible to reduce the number of peaks included in the spectral spectrum of the light transmitted through the laminated film 37. (Fig. 8). As a result, light in a predetermined mode can be selectively incident on the photoelectric conversion unit 22. When the color filter layer 38 is arranged on the laminated film 37, the light incident on the laminated film 37 may be in a single mode (single mode), and the light transmitted through the laminated film 37 may have a single peak. It becomes.

FIG. 9 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment. FIG. 10 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment.

FIG. 9 shows an example of a spectrum of light transmitted through the color filter layer 38. The horizontal axis represents the wavelength of this light, and the vertical axis represents the transmittance of this light at each wavelength. FIG. 10 shows another example of the spectrum of light transmitted through the color filter layer 38, where the horizontal axis represents the wavelength of this light and the vertical axis represents the transmittance of this light at each wavelength.

FIG. 9 shows a spectrum when the color filter layer 38 is, for example, a red (R) filter, a green (G) filter, a blue (B) filter, or the like. FIG. 10 shows a spectrum when the color filter layer 38 is replaced with a high-pass filter layer having 650 nm, 800 nm, and 900 nm as threshold wavelengths.

The color filter layer 38 may have any of the characteristics illustrated in FIG. 9, or may have other characteristics. Further, the color filter layer 38 may be an infrared light (IR) filter or a filter in which a red filter and a green filter are arranged so as to overlap each other.

Further, the color filter layer 38 may be replaced with a high-pass filter layer having any of the characteristics illustrated in FIG. 10, or may be replaced with another filter layer having wavelength selectivity. For example, the color filter layer 38 may be replaced with a metasurface, a surface plasmon resonance filter, or a fabrico resonator having a method different from that of the laminated film 37 of the present embodiment.

Further, the color filter layer 38 may be arranged below the resonator 51 instead of being arranged above the resonator 51. This also applies when the color filter layer 38 is replaced with another filter layer.

Further, in the present embodiment, an inter-pixel light-shielding film for preventing color mixing may be provided at the boundary between the resonators 51 and the boundary between the color filter layers 38. This makes it possible to prevent light from entering from each pixel 1 to the adjacent pixel 1 and improve wavelength selectivity.

Further, the polysilicon layer 43 has a large absorption coefficient on the short wavelength side and a large loss, but it is known that absorption can be suppressed by setting the thickness to 50 nm or less. Therefore, the thickness of each polysilicon layer 43 shown in FIG. 3 is set to 31 nm. Each polysilicon layer 43 shown in FIG. 3 may be replaced with an amorphous silicon (α-Si) layer or a microcrystal silicon (μc-Si) layer.

FIG. 11 is a flowchart showing the operation of the solid-state image sensor of the first embodiment.

The solid-state image sensor of the present embodiment can detect light by converting the light transmitted through the resonator 51 into an electric charge by the photoelectric conversion unit 22. The raw data of the spectroscopic spectrum obtained by this may be in a single mode or in multiple modes.

When the solid-state image sensor of the present embodiment acquires the multi-mode raw data (step S11), the multi-mode raw data is subjected to signal processing (step S12), and the multi-mode raw data is simply collected. It may be converted into one-mode data (step S13). In signal processing, for example, single mode and color mixing component removal are performed. This makes it possible to obtain a single-mode spectral spectrum by the action of signal processing instead of the action of the color filter layer 38.

FIG. 12 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment. FIG. 13 is another graph for explaining the characteristics of the solid-state image sensor of the first embodiment.

FIG. 12 shows an example of the spectroscopic spectrum obtained by the above signal processing. The horizontal axis represents the wavelength of light, and the vertical axis represents the full width at half maximum (FWHM: Full Width at) at each wavelength of the peak of light. Half Maximum). See FIG. 6 for FWHM. FIG. 13 shows the correspondence between the target wavelength (target value) and the output wavelength (measured value) for each wavelength of the spectral spectrum obtained by the above signal processing.

When the above signal processing is performed by applying Tychonoff's theorem, the full width at half maximum is less than 100 nm at a wavelength of approximately 400 to 900 nm, and a narrow spectrum can be obtained. did it. Further, as shown in FIG. 13, it was found that the output wavelength substantially matches the target wavelength.

As described above, the solid-state image sensor of the present embodiment includes the color filter layer 38 on (or below) the resonator 51 including the metamaterial layer 44. Therefore, according to the present embodiment, the resonator 51 can be mounted on the solid-state image sensor in a suitable manner, for example, the defect of the resonator 51 can be compensated for by the color filter layer 38.

For example, as shown in FIG. 12, it is possible to narrow the half width of the obtained light in a wide wavelength region. Further, by realizing the resonator 51 by the metamaterial layer 44, it becomes possible to easily mass-produce the resonator 51 capable of changing the peak wavelength of light. Such a resonator 51 can be easily laminated with the color filter layer 38. By stacking the color filter layer 38 on (or below) the resonator 51, it is possible to reduce the number of modes (wavelength range) of the light incident on the resonator 51, and the light transmitted through the resonator 51. It is possible to reduce the number of peaks included in the spectral spectrum of (Fig. 8). Signal detection by multi-spectroscopy as in this embodiment can be applied to various applications such as application to agriculture to evaluate vegetation state and application to biological recognition to detect biological parts such as human skin. Is.

Although the resonator 51 of the present embodiment is provided in the image sensor (solid-state image sensor), it may be provided in another sensor device that detects light. An example of such a sensor device is a ranging sensor.

Further, as described above, the laminated film 37 (see FIG. 3) of the present embodiment is a refractive index-modulated fabric-perot resonator by including the resonator 51. The resonator 51 of the present embodiment includes a metamaterial layer 44. However, the laminated film 37 may be a fabric pero resonator by including a resonator that does not include a metamaterial layer. For example, the laminated film 37 may be made of a material having a uniform refractive index. However, forming the resonator 51 using the metamaterial layer 44 has an advantage that the resonator 51 can be easily formed because, for example, it is not necessary to change the thickness of the resonator 51 for each pixel 1. This also applies to the laminated film 37 of the second to eleventh embodiments described later (see FIGS. 14, 19, 24, 30, 44, etc.).

Hereinafter, the second to eleventh embodiments will be described. These embodiments will be described mainly on the differences from the first embodiment and other embodiments, and the description of common points with the first embodiment and other embodiments will be omitted as appropriate.

(Second Embodiment)
FIG. 14 is a cross-sectional view showing the structure of the solid-state image sensor of the second embodiment.

FIG. 14 shows the substrate 21, the laminated film 37, and the color filter layer 38 included in one pixel 1, as in FIG. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 14, the laminated film 37 of the present embodiment includes an anti-reflection film (AR (Anti-Refrective) film) 45, a silicon oxide film 41, a polysilicon layer 43, and silicon oxide, which are sequentially formed on the substrate 21. A film 41, a polysilicon layer 43, a silicon oxide film 41, a metamaterial layer 44, a silicon oxide film 41, a polysilicon layer 43, a polysilicon film 41, a polysilicon layer 43, and a silicon oxide film 41 are provided. The metamaterial layer 44 of the present embodiment functions as a resonator 51 together with the silicon oxide film 41 in contact with the lower surface of the metamaterial layer 44 and the silicon oxide film 41 in contact with the upper surface of the metamaterial layer 44. The metamaterial layer 44 of the present embodiment has the same structure as the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes a resonator 51 to be a refractive index modulation type. It is a fabric pero resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 14, for example. The antireflection film 45, the silicon oxide film 41, the polysilicon layer 43, the silicon oxide film 41, and the polysilicon layer 43 under the resonator 51 are examples of the first layer of the present disclosure, and the polysilicon on the resonator 51. The layer 43, the silicon oxide film 41, the polysilicon layer 43, and the silicon oxide film 41 are examples of the second layer of the present disclosure.

In FIG. 14, a silicon oxide film 41 is provided under the metamaterial layer 44, and the silicon oxide film 41 is in contact with the lower surface of the metamaterial layer 44. Therefore, the lower surface of the metamaterial layer 44 is separated from the polysilicon layer 43 and the like below the metamaterial layer 44. The metamaterial layer 44 includes, for example, a silicon nitride portion 42a and a plurality of silicon oxide portions 41a (FIG. 4), and the silicon oxide film 41 is in contact with the lower surfaces of the silicon nitride portion 42a and the silicon oxide portion 41a. ing. In the present embodiment, the silicon oxide film 41 in contact with the lower surface of the metamaterial layer 44 is a transparent glass film, and is a part of the resonator 51 together with the metamaterial layer 44.

Further, in FIG. 14, a silicon oxide film 41 is further provided on the metamaterial layer 44, and the silicon oxide film 41 is in contact with the upper surface of the metamaterial layer 44. Therefore, the upper surface of the metamaterial layer 44 is separated from the polysilicon layer 43 and the like above the metamaterial layer 44. The metamaterial layer 44 includes, for example, a silicon nitride portion 42a and a plurality of silicon oxide portions 41a (FIG. 4), and the silicon oxide film 41 is in contact with the upper surfaces of the silicon nitride portion 42a and the silicon oxide portion 41a. ing. In the present embodiment, the silicon oxide film 41 in contact with the upper surface of the metamaterial layer 44 is a transparent glass film, and is a part of the resonator 51 together with the metamaterial layer 44.

According to this embodiment, it is possible to realize a solid-state image sensor having a narrow half-value width by wide-band multi-spectroscopy of 350 nm to 1000 nm. The laminated film 37 of the present embodiment includes four polysilicon layers 43, whereby the half width can be narrowed. Each polysilicon layer 43 can be formed by, for example, forming an amorphous silicon layer by CVD (Chemical Vapor Deposition) or the like, and crystallizing the amorphous silicon layer by annealing at 700 ° C. Further, each polysilicon layer 43 can be formed by forming a microcrystal silicon layer by, for example, CVD or the like, and crystallizing the microcrystal silicon layer by low-temperature annealing at 400 ° C. By forming the layer of reference numeral "43" as a polysilicon layer, it is possible to suppress the absorption of light in this layer. Further, in the present embodiment, the silicon oxide film 41 is arranged on the upper surface and the lower surface of the metamaterial layer 44 as a margin for microfabrication of the metamaterial layer 44.

The resonator length of the resonator 51 of the present embodiment is set to, for example, λ / n or more. λ represents the peak wavelength of the light passing through the resonator 51 in a vacuum. n represents the effective refractive index of the resonator 51. In the present embodiment, for example, the target value λ ₀ of this peak wavelength is used as the value of λ. It is desirable that the resonator length of the resonator 51 of the present embodiment is set to, for example, 700 nm / n or more. In the present embodiment, the resonator length of the resonator 51 is set to 1000 nm to achieve multimode, and the color filter layer 38 is arranged above the resonator 51 to have a wavelength-selective structure. Has been realized.

FIG. 15 is a schematic view showing the structure of the solid-state image sensor of the second embodiment. The pixel array region 2 of the solid-state image sensor of the present embodiment has the structure shown in FIG.

In FIG. 15, each square represents one pixel 1, and the reference numeral R represents a unit region including 16 pixels 1. The numbers "1 to 16" in each unit area R indicate that each unit area R includes 16 types of pixels 1 corresponding to 16 types of colors. As described above, the pixel array region 2 of the present embodiment has a periodic array with 4 × 4 pixels 1 as a unit.

In this embodiment, 16 types of pixels 1 include resonators 51 (metamaterial layer 44) having different structures from each other (see also FIG. 5). As a result, a 16-spectral solid-state image sensor can be realized. The pixel array region 2 of the present embodiment has a structure in which a plurality of unit regions R are repeatedly arranged in the X direction and the Y direction.

The number of pixels 1 included in each unit area R may be 5 × 5, 6 × 6, or n × n (n is an integer of 2 or more). This makes it possible to realize a solid-state image sensor suitable for multi-spectral spectroscopy, and it is possible to obtain a multi-spectral image by performing signal processing on a plurality of spectroscopys. The image obtained by this signal processing is suitable for application to various applications such as agriculture and biometric detection.

The number of pixels 1 included in each unit area R may be m × n (m is an integer of 2 or more different from n). However, when it is preferable to handle pixels 1 of the power of 2 types, the number of pixels 1 included in each unit region R is preferably n × n.

FIG. 16 is a graph for explaining the characteristics of the solid-state image sensor of the second embodiment.

FIG. 16 shows an example of the spectrum of light transmitted through the laminated film 37, the horizontal axis represents the wavelength of this light, and the vertical axis represents the quantum efficiency at each wavelength of this light. FIG. 16 shows a spectrum when the color filter layer 38 is arranged above the laminated film 37, as in FIG. 8 described above. With such an arrangement, it is possible to reduce the number of modes (wavelength range) of the light incident on the laminated film 37, and reduce the number of peaks included in the spectral spectrum of the light transmitted through the laminated film 37. Is possible.

FIG. 17 is another graph for explaining the characteristics of the solid-state image sensor of the second embodiment. FIG. 18 is another graph for explaining the characteristics of the solid-state image sensor of the second embodiment.

FIG. 17 shows an example of the spectroscopic spectrum obtained by the signal processing of FIG. 11, similarly to FIG. 12 described above. The horizontal axis represents the wavelength of light, and the vertical axis represents each of the peaks of this light. Represents the full width at half maximum (FWHM) at wavelength. FIG. 18 shows the correspondence between the target wavelength (target value) and the output wavelength (measured value) for each wavelength of the spectral spectrum obtained by the above signal processing, similarly to FIG. 13 described above.

When the above signal processing was carried out by applying Tychonoff's theory, as shown in FIG. 17, it was possible to obtain a narrow spectrum with a single peak and a half width of 30 nm or less. Further, as shown in FIG. 18, it was found that the output wavelength substantially matches the target wavelength.

As described above, the solid-state image sensor of the present embodiment includes the color filter layer 38 on (or below) the resonator 51 including the metamaterial layer 44, as in the first embodiment. Therefore, according to the present embodiment, the resonator 51 can be mounted on the solid-state image sensor in a suitable manner, for example, the defect of the resonator 51 can be compensated for by the color filter layer 38.

(Third Embodiment)
FIG. 19 is a cross-sectional view showing the structure of the solid-state image sensor of the third embodiment.

FIG. 19 shows the substrate 21, the laminated film 37, and the color filter layer 38 included in one pixel 1, as in FIG. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 19, the laminated film 37 of the present embodiment includes an antireflection film 45, a silicon oxide film 41, an amorphous silicon layer 46, a silicon oxide film 41, a metamaterial layer 44, and oxidation formed in this order on the substrate 21. It includes a silicon film 41, an amorphous silicon layer 46, and a silicon oxide film 41. The metamaterial layer 44 of the present embodiment functions as a resonator 51 together with the silicon oxide film 41 in contact with the lower surface of the metamaterial layer 44 and the silicon oxide film 41 in contact with the upper surface of the metamaterial layer 44. The metamaterial layer 44 of the present embodiment has the same structure as the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes a resonator 51 to be a refractive index modulation type. It is a fabric pero resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 19, for example. The antireflection film 45, the silicon oxide film 41, and the amorphous silicon layer 46 under the resonator 51 are examples of the first layer of the present disclosure, and the amorphous silicon layer 46 and the silicon oxide film 41 on the resonator 51 are the present invention. This is an example of the second layer of disclosure.

According to the present embodiment, by forming the layer of reference numeral “46” as an amorphous silicon layer, this layer can be easily formed without annealing.

The resonator length of the resonator 51 of the present embodiment is set to, for example, λ / n or more. λ represents the peak wavelength of the light passing through the resonator 51 in a vacuum. n represents the effective refractive index of the resonator 51. In the present embodiment, for example, the target value λ ₀ of this peak wavelength is used as the value of λ. It is desirable that the resonator length of the resonator 51 of the present embodiment is set to, for example, 700 nm / n or more. In the present embodiment, the resonator length of the resonator 51 is set to 1000 nm to achieve multimode, and the color filter layer 38 is arranged above the resonator 51 to have a wavelength-selective structure. Has been realized.

FIG. 20 is a graph for explaining the characteristics of the solid-state image sensor of the third embodiment.

FIG. 20 shows an example of a spectrum of light transmitted through the laminated film 37. The horizontal axis represents the wavelength of this light, and the vertical axis represents the quantum efficiency of this light at each wavelength. FIG. 20 shows a spectrum when the color filter layer 38 is arranged above the laminated film 37, as in FIG. 8 described above. With such an arrangement, it is possible to reduce the number of modes (wavelength range) of the light incident on the laminated film 37, and reduce the number of peaks included in the spectral spectrum of the light transmitted through the laminated film 37. Is possible.

FIG. 21 is another graph for explaining the characteristics of the solid-state image sensor of the third embodiment. FIG. 22 is another graph for explaining the characteristics of the solid-state image sensor of the third embodiment.

FIG. 21 shows an example of the spectroscopic spectrum obtained by the signal processing of FIG. 11, similarly to FIG. 12 described above. The horizontal axis represents the wavelength of light, and the vertical axis represents each of the peaks of this light. Represents the full width at half maximum (FWHM) at wavelength. FIG. 22 shows the correspondence between the target wavelength (target value) and the output wavelength (measured value) for each wavelength of the spectral spectrum obtained by the above signal processing, similarly to FIG. 13 described above.

When the above signal processing was carried out by applying Tychonoff's theory, as shown in FIG. 21, it was possible to obtain a narrow spectrum with a single peak and a half width of 30 nm or less. Further, as shown in FIG. 22, it was found that the output wavelength substantially matches the target wavelength.

FIG. 23 is another graph for explaining the characteristics of the solid-state image sensor of the third embodiment.

FIG. 23 shows an example of the spectroscopic spectrum obtained by the above signal processing, the horizontal axis represents the wavelength of light, and the vertical axis represents the output signal (measurement signal) of this light. As shown in FIG. 23, this light is in a single mode.

As described above, the solid-state image sensor of the present embodiment includes the color filter layer 38 on (or below) the resonator 51 including the metamaterial layer 44, as in the first embodiment. Therefore, according to the present embodiment, the resonator 51 can be mounted on the solid-state image sensor in a suitable manner, for example, the defect of the resonator 51 can be compensated for by the color filter layer 38.

(Fourth Embodiment)
FIG. 24 is a cross-sectional view showing the structure of the solid-state image sensor of the fourth embodiment.

FIG. 24 shows the substrate 21, the laminated film 37, and the color filter layer 38 included in one pixel 1, as in FIG. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 24, the laminated film 37 of the present embodiment includes a silicon oxide film 41, a silicon nitride film 42, a silicon oxide film 41, a polysilicon layer 43, a metamaterial layer 44, and a poly, which are sequentially formed on the substrate 21. It includes a silicon layer 43 and a silicon oxide film 41. The metamaterial layer 44 functions as a resonator 51. The metamaterial layer 44 of the present embodiment has the same structure as the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes a resonator 51 to be a refractive index modulation type. It is a fabric pero resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 24, for example. The silicon oxide film 41, the silicon nitride film 42, the silicon oxide film 41, and the polysilicon layer 43 under the resonator 51 are examples of the first layer of the present disclosure, and the polysilicon layer 43 and the silicon oxide on the resonator 51 The film 41 is an example of the second layer of the present disclosure.

The resonator length of the resonator 51 of the present embodiment is set to, for example, λ / n or more. λ represents the peak wavelength of the light passing through the resonator 51 in a vacuum. n represents the effective refractive index of the resonator 51. In the present embodiment, for example, the target value λ ₀ of this peak wavelength is used as the value of λ. It is desirable that the resonator length of the resonator 51 of the present embodiment is set to, for example, 700 nm / n or more. In the present embodiment, the resonator length of the resonator 51 is set to 1500 nm to achieve multimode, and the color filter layer 38 is arranged above the resonator 51 to have a wavelength-selective structure. Has been realized.

The metamaterial layer 44 includes, for example, a silicon nitride portion 42a and a plurality of silicon oxide portions 41a (FIG. 4). In the present embodiment, the silicon nitride portion 42a may be replaced with a first portion formed of a first material other than the silicon nitride film 42, and these silicon oxide portions 41a may be replaced with a second portion other than the silicon oxide film 41. It may be replaced with a second portion made of material. In this case, the refractive index of the second material is set to a value different from the refractive index of the first material.

The solid-state image sensor of the present embodiment includes a pixel 1 having sensitivity only to a single wavelength of about 940 nm, and such a pixel 1 has the structure shown in FIG. 24. It is known that the spectrum of sunlight does not contain much component of 940 nm. Therefore, according to the present embodiment, light having a wavelength of 940 nm is used for distance measurement, face recognition, etc., and light having a wavelength of 940 nm is detected by the above pixel 1, so that noise caused by sunlight is reduced. It is possible to realize distance and face recognition.

The light having a wavelength of 940 nm corresponds to near infrared light (NIR), and the luminosity factor of the human eye becomes zero. Therefore, according to the present embodiment, it is possible to perform distance measurement and face recognition without causing discomfort to humans. In this embodiment, light having a wavelength of 940 nm may be applied to other ToF (Time of Flight) techniques. Further, in the present embodiment, near-infrared light having a wavelength other than 940 nm may be used. Further, the solid-state imaging device of the present embodiment may include only pixels 1 for near-infrared light, or may also include other pixels 1 such as pixels 1 for red, green, and blue.

FIG. 25 is a graph for explaining the characteristics of the solid-state image sensor of the fourth embodiment. FIG. 26 is another graph for explaining the characteristics of the solid-state image sensor of the fourth embodiment. FIG. 27 is another graph for explaining the characteristics of the solid-state image sensor of the fourth embodiment.

FIG. 25 shows an example of the spectrum of light transmitted through the laminated film 37. The horizontal axis represents the wavelength of this light, and the vertical axis represents the quantum efficiency of this light at each wavelength. FIG. 26 shows an example of a spectrum of light transmitted through the color filter layer 38. The horizontal axis represents the wavelength of this light, and the vertical axis represents the transmittance of this light at each wavelength. FIG. 27 shows another example of the spectrum of light transmitted through the laminated film 37, where the horizontal axis represents the wavelength of this light and the vertical axis represents the quantum efficiency of this light at each wavelength.

FIG. 25 shows an example of the spectral characteristics when the color filter layer 38 is not arranged above the laminated film 37. In this case, the light having a wavelength of 940 nm is more difficult to detect than the light having another wavelength.

Therefore, in the present embodiment, the color filter layer 38 having the characteristics shown in FIG. 26 is arranged above the resonator 51. This makes it possible for the color filter layer 38 to cut light having a wavelength of about 900 nm or less.

FIG. 27 shows an example of the spectral characteristics when such a color filter layer 38 is arranged above the resonator 51. In FIG. 27, single-mode and single-peak light having a peak wavelength of 940 nm and a half-value width of 60 nm is obtained without Tychonoff's signal processing. This makes it possible to easily detect light having a wavelength of 940 nm.

FIG. 28 is a flowchart showing the operation of the solid-state image sensor of the fourth embodiment.

The solid-state image sensor of the present embodiment can detect light by converting the light transmitted through the resonator 51 into an electric charge by the photoelectric conversion unit 22. The raw data of the spectroscopic spectrum thus obtained may be in a single mode as shown in FIG. 27. In this case, the process shown in FIG. 11 may be replaced with the process shown in FIG. 28.

When the solid-state image sensor of the present embodiment acquires the raw data in the single mode (step S21), the raw data in the single mode is signal-processed (step S22), and the raw data in the single mode is processed. The data may be converted to another single mode data (step S23). In this signal processing, for example, the single mode is not performed, but the color mixing component is removed. This makes it possible to obtain a single-mode spectral spectrum with less noise by signal processing.

As described above, according to the present embodiment, it is possible to realize a solid-state image sensor suitable for ToF technology and the like.

(Fifth Embodiment)
FIG. 29 is a schematic diagram for explaining the structure of the solid-state image sensor of the fifth embodiment. A of FIG. 29 shows the solid-state image sensor of the first embodiment, and B of FIG. 29 shows the solid-state image sensor of the fifth embodiment.

FIG. 29A shows the change in the refractive index (effective refractive index) n in the laminated film 37 when the polysilicon layers 43 are arranged above and below the metamaterial layer 44. The metamaterial layer 44 has a structure in which a plurality of silicon oxide portions 41a are embedded in the silicon nitride portion 42a (or a structure in which a plurality of silicon nitride portions 42a are embedded in the silicon oxide portion 41a). .. In A of FIG. 29, the effective refractive index of the metamaterial layer 44 is set to be smaller than the refractive index of the silicon oxide films 41 above and below the metamaterial layer 44.

FIG. 29B shows the change in the refractive index (effective refractive index) n in the laminated film 37 when the silicon oxide film 41 is arranged above and below the metamaterial layer 44. The metamaterial layer 44 has a structure in which a plurality of silicon oxide portions 41a are embedded in the polysilicon portion (or a structure in which a plurality of polysilicon portions are embedded in the silicon oxide portion 41a). The shape of these polysilicon portions is the same as the shape of the silicon nitride portion 42a described above. In FIG. 29B, the effective refractive index of the metamaterial layer 44 is set to be larger than the refractive index of the silicon oxide films 43 above and below the metamaterial layer 44. According to the present embodiment, by adopting such a structure, for example, it is possible to reduce the number of layers and films in the laminated film 37, and it is possible to make the laminated film 37 thinner.

FIG. 30 is a cross-sectional view showing the structure of the solid-state image sensor of the fifth embodiment. The structure shown in FIG. 30 specifically corresponds to the structure shown in FIG. 29B.

FIG. 30 shows the substrate 21, the laminated film 37, and the color filter layer 38 included in one pixel 1, as in FIG. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 30, the laminated film 37 of the present embodiment includes an antireflection film 45, a silicon oxide film 41, a polysilicon layer 43, a silicon oxide film 41, a metamaterial layer 44, and oxidation formed in this order on the substrate 21. It includes a silicon film 41, a polysilicon layer 43, and a silicon oxide film 41. The metamaterial layer 44 of this embodiment functions as a resonator 51. The metamaterial layer 44 of the present embodiment has the structure described with reference to B of FIG. 29, and the laminated film 37 of the present embodiment includes the resonator 51, so that the refractive index modulation type fabric pero resonator is included. It has become. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 30, for example. The antireflection film 45, the silicon oxide film 41, and the polysilicon layer 43 under the resonator 51 are examples of the first layer of the present disclosure, and the polysilicon layer 43 and the silicon oxide film 41 on the resonator 51 are the present invention. This is an example of the second layer of disclosure.

FIG. 31 is a graph for explaining the characteristics of the solid-state image sensor of the fifth embodiment.

FIG. 31 shows an example of the spectrum of light transmitted through the laminated film 37. The horizontal axis represents the wavelength of this light, and the vertical axis represents the quantum efficiency of this light at each wavelength. FIG. 31 shows a spectrum when the color filter layer 38 is arranged above the laminated film 37, as in FIG. 8 described above. With such an arrangement, it is possible to reduce the number of modes (wavelength range) of the light incident on the laminated film 37, and reduce the number of peaks included in the spectral spectrum of the light transmitted through the laminated film 37. Is possible.

FIG. 32 is another graph for explaining the characteristics of the solid-state image sensor of the fifth embodiment. FIG. 33 is another graph for explaining the characteristics of the solid-state image sensor of the fifth embodiment.

FIG. 32 shows an example of the spectral spectrum obtained by the signal processing of FIG. 11, similarly to FIG. 12 described above, where the horizontal axis represents the wavelength of light and the vertical axis represents each of the peaks of this light. Represents the full width at half maximum (FWHM) at wavelength. FIG. 33 shows the correspondence between the target wavelength (target value) and the output wavelength (measured value) with respect to each wavelength of the spectral spectrum obtained by the above signal processing, similarly to FIG. 13 described above.

When the above signal processing was carried out by applying Tychonoff's theory, a narrow spectrum could be obtained as shown in FIG. Further, as shown in FIG. 33, it was found that the output wavelength substantially matches the target wavelength.

As described above, according to the present embodiment, although the laminated film 37 is thinner than the above-mentioned other embodiments, it is possible to maintain the same narrow full width at half maximum as the above-mentioned other embodiments. Become. In the other embodiment described above, the thickness of the laminated film 37 excluding the antireflection film 45 is larger than 1 μm, whereas in the present embodiment, the thickness of the laminated film 37 excluding the antireflection film 45 is smaller than 1 μm. ing.

(Sixth Embodiment)
FIG. 34 is a cross-sectional view showing the structure of the solid-state image sensor of the sixth embodiment.

FIG. 34 shows the substrate 21, the laminated film 37, and the color filter layer 38 included in one pixel 1, as in FIG. The photoelectric conversion unit 22 and the like in the substrate 21, the flattening film 36 on the substrate 21, the on-chip lens 39, and the like are not shown.

As shown in FIG. 34, the laminated film 37 of the present embodiment includes a silicon oxide film 41, a silicon nitride film 42, a silicon oxide film 41, a polysilicon layer 43, a metamaterial layer 44, and a poly, which are sequentially formed on the substrate 21. It includes a silicon layer 43 and a silicon oxide film 41. The metamaterial layer 44 functions as a resonator 51. The metamaterial layer 44 of the present embodiment has the same structure as the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes a resonator 51 to be a refractive index modulation type. It is a fabric pero resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 34, for example. The silicon oxide film 41, the silicon nitride film 42, the silicon oxide film 41, and the polysilicon layer 43 under the resonator 51 are examples of the first layer of the present disclosure, and the polysilicon layer 43 and the silicon oxide on the resonator 51 The film 41 is an example of the second layer of the present disclosure.

FIG. 34 shows how the main light rays are obliquely incident on the color filter layer 38, the laminated film 37, and the substrate 21 due to the image height of the solid-state image sensor of the present embodiment. FIG. 34 shows the angle of the traveling direction of the main ray with respect to the direction perpendicular to the upper surface of the substrate 21 (Z direction). The solid-state image sensor of the present embodiment is provided in the camera, and the angle of FIG. 34 is fixed to a constant value by the structure of the camera.

In the resonator 51 having the structure shown in FIG. 4, when the main ray is obliquely incident on the laminated film 37 due to the image height, the light transmitted through the laminated film 37 is compared with the case where the main ray is vertically incident on the laminated film 37. The peak wavelength of is shifted to the short wavelength side (short wavelength shift). In this embodiment, a method for correcting this short wavelength shift will be described. Specifically, by changing the effective refractive index of the resonator 51, the peak wavelength of the light transmitted through the laminated film 37 is shifted to the long wavelength side, and the short wavelength shift is corrected.

FIG. 35 is a graph for explaining the characteristics of the solid-state image sensor of the sixth embodiment.

FIG. 35 shows two examples (K1 and K2) of the spectrum of light transmitted through the laminated film 37, where the horizontal axis represents the wavelength of this light and the vertical axis represents the transmittance of this light at each wavelength. Represents. In FIG. 35, K1 shows the transmitted light when the main light ray is vertically incident on the laminated film 37, and K2 is the transmitted light when the main light ray is incident on the laminated film 37 at an inclination of 35 degrees.

FIG. 35 shows that when the main ray is obliquely incident on the laminated film 37 due to the image height, a short wavelength shift from K1 to K2 occurs. In the present embodiment, when the main light beam is incident on the laminated film 37 at an inclination of 35 degrees, the transmitted light of K3 instead of K2 is output from the laminated film 37 by changing the effective refractive index of the resonator 51.

FIG. 36 is a plan view for explaining the structure of the resonator 51 (metamaterial layer 44) of the sixth embodiment.

FIG. 36 shows five examples of the metamaterial layer 44. The arrow A shows how the proportion of the silicon nitride portion 42a in the metamaterial layer 44 gradually increases, and in other words, shows how the metamaterial layer 44 _{changes from SiO 2} rich to SiN rich. There is.

In the present embodiment, the effective refractive index of the resonator 51 used for imaging, distance measurement, etc. is set based on the image height. For example, when the angle of FIG. 34 is close to 0 degrees, the _{resonator 51 including the SiO 2-} rich metamaterial layer 44 is used. On the other hand, when the angle of FIG. 34 is large, the resonator 51 including the SiN-rich metamaterial layer 44 is used. This makes it possible to change the transmitted light from K2 to K3 and correct the short wavelength shift.

In this embodiment, for example, a plurality of resonators 51 (metamaterial layers 44) are arranged above the substrate 21 in the arrangement shown in FIG. 36. Reference numeral C shown in FIG. 36 indicates the center of the pixel array region 2 (the center of the imaging surface). In the present embodiment, the _{resonator 51 including the SiO 2-} rich metamaterial layer 44 is arranged near the center C, and the resonator 51 including the SiN-rich metamaterial layer 44 is arranged far from the center C.

(7th Embodiment)
FIG. 37 is a plan view for explaining the structure of the solid-state image sensor of the seventh embodiment.

FIG. 37 shows the center C (center of the imaging surface) of the pixel array region 2 and the center L of the on-chip lens 39 of some pixels 1. In the present embodiment, the on-chip lens 39 will be abbreviated as "lens 39".

The planar shape of each lens 39 of the present embodiment is asymmetric with respect to the center L of each lens 39, except for the lens 39 located at the center C of the pixel array region 2. FIG. 37 shows one lens 39 located at the center C of the pixel array region 2 and having a symmetrical planar shape, and eight lenses located outside the center C of the pixel array region 2 and having an asymmetric planar shape. The lens 39 is illustrated. In the present embodiment, the position of the center L of each lens 39 is biased toward the center C of the pixel array region 2.

FIG. 38 is a cross-sectional view showing the structure of the solid-state image sensor of the seventh embodiment.

FIG. 38 shows a substrate 21, a laminated film 37, a color filter layer 38, and a lens 39 included in one pixel 1. The photoelectric conversion unit 22 and the like in the substrate 21 and the flattening film 36 and the like on the substrate 21 are not shown. As shown in FIG. 38, the lens 39 has an asymmetric planar shape. As shown in FIGS. 37 and 38, each lens 39 of the present embodiment has a shape including a plurality of annular convex portions and a plurality of annular concave portions alternately.

As shown in FIG. 38, the laminated film 37 of the present embodiment includes an antireflection film 45, a silicon oxide film 41, an amorphous silicon layer 46, a metamaterial layer 44, an amorphous silicon layer 46, and an amorphous silicon layer 46, which are sequentially formed on the substrate 21. The silicon oxide film 41 is provided. The metamaterial layer 44 functions as a resonator 51. The metamaterial layer 44 of the present embodiment has the same structure as the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes a resonator 51 to be a refractive index modulation type. It is a fabric pero resonator. The antireflection film 45, the silicon oxide film 41, and the amorphous silicon layer 46 under the resonator 51 are examples of the first layer of the present disclosure, and the amorphous silicon layer 46 and the silicon oxide film 41 on the resonator 51 are the present invention. This is an example of the second layer of disclosure.

In the present embodiment, the traveling direction of the obliquely incident main light beam is corrected by a method different from that of the sixth embodiment. Specifically, the traveling direction of the obliquely incident main light beam is bent in the vertical direction by the lens 39 having an asymmetric plane shape, and this light is collected. FIG. 38 shows a plurality of wavefronts (equal phase planes) S of light obliquely incident on the lens 39 and collected.

As described above, each lens 39 of the present embodiment is microfabricated so as to alternately include a plurality of annular convex portions and a plurality of annular concave portions. As a result, the effective refractive index of each part of each lens 39 becomes higher as it approaches the center C of the pixel array region 2. Therefore, according to the present embodiment, the traveling direction of the main light beam can be bent in the vertical direction as described above, and the short wavelength shift can be suppressed.

FIG. 39 is a plan view and a cross-sectional view for explaining the structure of a modified example of the solid-state image sensor of the seventh embodiment.

A in FIG. 39 shows a different type of lens 39 than the lens 39 in FIGS. 37 and 38. As an example, A in FIG. 39 shows the planar shape of the lens 39 of nine pixels 1 located near the center C of the pixel array region 2. The arrow shown by A in FIG. 39 indicates the direction of light incident on each pixel 1. B in FIG. 39 shows a vertical cross section of the solid-state image sensor shown in A in FIG. 39.

Each lens 39 of the present modification includes a low refractive index portion 39a and a high refractive index portion 39b, and the low refractive index portion 39a surrounds the high refractive index portion 39b. The planar shape of each lens 39 in this modification is asymmetric with respect to the center of each lens 39, except for the lens 39 located at the center C of the pixel array region 2. Specifically, the high refractive index portion 39b is not arranged at the center of the low refractive index portion 39a, and is biased toward the center C of the pixel array region 2 with respect to the center of the low refractive index portion 39a.

According to this modification, it is possible to realize the same operation as that of the lens 39 of FIGS. 37 and 38 without performing the microfabrication as in the lens 39 of FIGS. 37 and 38. This makes it possible to suppress short wavelength shifts. The lens 39 of this modification may be made of three or more kinds of materials having different refractive indexes.

(8th Embodiment)
40 and 41 are cross-sectional views showing a method of manufacturing the solid-state image sensor of the eighth embodiment, and show a step of manufacturing the solid-state image sensor shown in FIG.

First, as shown in A of FIG. 40, the p-type semiconductor region 23, the n-type semiconductor region 24, the p-type semiconductor region 25, the pixel separation layer 26, the p-well layer 27, and the floating diffusion are formed in the substrate 21 or on the substrate 21. A portion 28, a gate insulating film 17, a gate electrode 16, and the like are formed. In this way, pixel transistors such as the photoelectric conversion unit 22 and the transfer transistor Tr1 are formed. Next, as shown in A of FIG. 40, the interlayer insulating film 15 and the wiring layers 12 to 14 are alternately formed on the front side of the substrate 21. The step A in FIG. 40 is executed with the front side of the substrate 21 facing up and the back side of the substrate 21 facing down.

Next, as shown in FIG. 40B, the support substrate 11 is adhered to the front side of the substrate 21 via the interlayer insulating film 15, and then the substrate 21 is turned upside down. FIG. 40B shows a state in which the front side of the substrate 21 faces downward and the back side of the substrate 21 faces upward. Next, as shown in FIG. 40B, after the substrate 21 is thinned from the back surface, a groove 31 having a predetermined depth is formed in the substrate 21 by etching. The groove 31 is formed in the pixel separation layer 26 from the back surface of the substrate 21.

Next, as shown in A of FIG. 41, the fixed charge film 33 and the insulating film 34 are sequentially formed on the back surface of the substrate 21. As a result, the fixed charge film 33 is formed on the side surface and the bottom surface of the groove 31 and on the photoelectric conversion unit 22. Further, the insulating film 34 is embedded in the groove 31 via the fixed charge film 33, and is formed on the photoelectric conversion unit 22 via the fixed charge film 33. In this way, the element separating portion 32 is formed in the groove 31.

Next, as shown in A of FIG. 41, a light-shielding film 35 is formed in a predetermined region on the insulating film 34 formed on the back surface of the substrate 21. The light-shielding film 35 is formed, for example, by forming a material layer of the light-shielding film 35 on the insulating film 34 and patterning the material layer in a predetermined shape. The light-shielding film 35 of the present embodiment is formed on the element separation portion 32. Next, as shown in A of FIG. 41, the flattening film 36 is formed on the insulating film 34 via the light-shielding film 35.

Next, as shown in B of FIG. 41, a laminated film 37, a color filter layer 38, and an on-chip lens 39 are sequentially formed above each photoelectric conversion unit 22 via a flattening film 36. In this way, the solid-state image sensor shown in FIG. 2 is manufactured.

42 and 43 are cross-sectional views showing the details of the manufacturing method of the solid-state image sensor of the eighth embodiment, and show the details of the process shown in B of FIG. 41.

First, as shown in A of FIG. 42, the antireflection film 45 and oxidation are performed by CVD via a fixed charge film 33, an insulating film 34, a light-shielding film 35, a flattening film 36, etc., which are not shown, above the substrate 21. The silicon film 41, the amorphous silicon layer 46, the silicon oxide film 41, and the silicon nitride portion 42a are formed in this order. The silicon nitride portion 42a at this point is a flat silicon nitride film.

Next, as shown in B of FIG. 42, the silicon nitride portion 42a is processed by lithography and etching using a resist film. As a result, a plurality of openings for embedding the plurality of silicon oxide films 41a are formed in the silicon nitride film 42a. The silicon nitride portion 42a is processed by, for example, RIE (Reactive Ion Etching).

Next, as shown in A of FIG. 43, a plurality of silicon oxide portions 41a are embedded in the plurality of openings of the silicon nitride portion 42a. In this way, the metamaterial layer 44 including the silicon nitride portion 42a and the plurality of silicon oxide portions 41a is formed on the silicon oxide film 41. The plurality of silicon oxide portions 41a are formed by forming a silicon oxide film on the entire surface of the substrate 21 by CVD and flattening the upper surface of the silicon oxide film by CMP. By flattening the upper surface of the silicon oxide film, the silicon oxide film outside the opening is removed, and the silicon oxide film inside the opening becomes the silicon oxide portion 41a.

Next, as shown in A of FIG. 43, a silicon oxide film 41 is formed on the metamaterial layer 44 by CVD. In this way, the resonator 51 including the silicon oxide film 41, the metamaterial layer 44 on the silicon oxide film, and the silicon oxide film 41 on the metamaterial layer 44 is formed. The silicon oxide film 41 on the metamaterial layer 44 may be formed at the same time as the silicon oxide portion 41a. In this case, the above-mentioned CMP is performed not until the time when the silicon oxide film outside the opening is completely removed, but until the time when a part of the silicon oxide film outside the opening remains. As a result, the silicon oxide film remaining outside the opening becomes the silicon oxide film 41 on the metamaterial layer 44.

Next, as shown in B of FIG. 43, the amorphous silicon layer 46 and the silicon oxide film 41 are sequentially formed on the resonator 51 by CVD. In this way, the laminated film 37 is formed above the substrate 21. Next, as shown in B of FIG. 43, the color filter layer 38 is formed on the laminated film 37. The color filter layer 38 is formed, for example, by applying a material of the color filter layer 38 (for example, a photosensitive resin material) on the laminated film 37 and processing the material into the shape of the color filter layer 38.

After that, the on-chip lens 39 is formed on the color filter layer 38. In this way, the solid-state image sensor of the present embodiment is manufactured.

The methods shown in FIGS. 40 to 43 can be applied to any of the solid-state image sensors of the first to seventh embodiments. However, the structure of the laminated film 37 changes according to the embodiment. For example, when forming the laminated film 37 of the first embodiment, the silicon oxide film 41, the silicon nitride film 42, the silicon oxide film 41, the polysilicon layer 43, the metamaterial layer 44, and the polysilicon layer 43 are formed on the substrate 21. And the silicon oxide film 41 is formed in order (see FIG. 3). Further, the methods shown in FIGS. 40 to 43 can also be applied to the solid-state image sensor of the ninth embodiment described later.

As described above, in the present embodiment, the solid-state image sensor is manufactured by the methods shown in FIGS. 40 to 43. This makes it possible, for example, to easily form the metamaterial layer 44 and other films and layers by the general methods of semiconductor manufacturing processes.

When forming the metamaterial layer 44 including the silicon oxide portion 41a and the plurality of silicon nitride portions 42a, a plurality of openings are formed in the silicon oxide portion 41a, and a plurality of openings are formed in these openings of the silicon oxide portion 41a. A plurality of silicon nitride portions 42a are embedded.

(9th Embodiment)
FIG. 44 is a cross-sectional view showing the structure of the solid-state image sensor of the ninth embodiment.

FIG. 44 shows a compound semiconductor substrate 29 included in one pixel 1, a laminated film 37, and a color filter layer 38. In this embodiment, the substrate 21 is replaced with the compound semiconductor substrate 29. The structure of the component in the compound semiconductor substrate substrate 29 of the present embodiment is the same as the structure of the component in the substrate 21. That is, the compound semiconductor substrate 29 of the present embodiment includes the photoelectric conversion unit 22 and the like like the substrate 21. However, the illustration of the photoelectric conversion unit 22 in the compound semiconductor substrate 29, the flattening film 36 on the substrate 29, the on-chip lens 39, etc. is omitted.

The compound semiconductor substrate 29 of the present embodiment includes an InGaAs (indium gallium arsenide) layer 29a and an InP (indium phosphide) layer 29b formed on the InGaAs layer 29a. The InP layer 29b of the present embodiment is an InP substrate thinned by etching. In the present embodiment, the InGaAs layer 29a is formed on the surface of the InP substrate by crystal growth, and then the InP layer 29b is formed by thinning the InP substrate. The photoelectric conversion unit 22 of the present embodiment is formed in the InGaAs layer 29a instead of the substrate 21.

The InGaAs layer 29a may be replaced with another semiconductor layer. Examples of such a semiconductor layer are a SiGe (silicon germanium) layer, a CuInGaSe (copper indium gallium selenium) layer, and a quantum dot film. It is desirable that the semiconductor layer is formed of a material capable of detecting light having a wavelength longer than the wavelength that can be detected by the silicon layer. Further, the compound semiconductor substrate 29 may be entirely formed of the compound semiconductor, or only a part thereof may be formed of the compound semiconductor.

As shown in FIG. 44, the laminated film 37 of the present embodiment has an ITO (indium tin oxide) layer 47, a silicon oxide film 41, a silicon nitride film 42, a silicon oxide film 41, and an amorphous layer formed on the InP layer 29b in this order. Silicon layer 46, silicon oxide film 41, amorphous silicon layer 46, silicon oxide film 41, metamaterial layer 44, silicon oxide film 41, amorphous silicon layer 46, silicon oxide film 41, amorphous silicon layer 46, and silicon oxide film 41. I have.

The metamaterial layer 44 of this embodiment functions as a resonator 51. As will be described later, the metamaterial layer 44 of the present embodiment has a structure similar to that of the metamaterial layer 44 of the first embodiment, and the laminated film 37 of the present embodiment includes the resonator 51. , It is a refractive index modulation type fabric pero resonator. Each layer and each film in the laminated film 37 has a thickness shown in FIG. 44, for example. The ITO layer 47, the silicon oxide film 41, the silicon nitride film 42, the silicon oxide film 41, the amorphous silicon layer 46, the silicon oxide film 41, and the amorphous silicon layer 46 under the resonator 51 are examples of the first layer of the present disclosure. be. The amorphous silicon layer 46, the silicon oxide film 41, the amorphous silicon layer 46, and the silicon oxide film 41 on the resonator 51 are examples of the second layer of the present disclosure.

FIG. 45 is a perspective view showing the structure of the resonator 51 (metamaterial layer 44) of the ninth embodiment.

As shown in FIG. 4, the metamaterial layer 44 of the present embodiment is formed of an amorphous silicon portion 46a formed of an amorphous silicon layer 46 and a silicon oxide film 41, and is provided in the amorphous silicon portion 46a. It contains a plurality of silicon oxide portions 41a. The shapes of the amorphous silicon portion 46a and the silicon oxide portion 41a of the present embodiment are the same as the shapes of the silicon nitride portion 42a and the silicon oxide portion 41a of the first embodiment, respectively. The amorphous silicon portion 46a is an example of the first portion formed of the first material, and the silicon oxide portion 41a is an example of a plurality of second portions formed of the second material.

The silicon oxide portion 41a and the amorphous silicon portion 46a have different refractive indexes. Specifically, the refractive index of the amorphous silicon portion 46a is higher than the refractive index of the silicon oxide portion 41a. Therefore, the effective refractive index of the resonator 51 of the present embodiment depends on the volume ratio of the silicon oxide portion 41a and the amorphous silicon portion 46a in the metamaterial layer 44. Therefore, in the present embodiment, the effective refractive index of the resonator 51 can be changed for each pixel by changing the volume ratio of the silicon oxide portion 41a and the amorphous silicon portion 46a for each pixel 1. As a result, the peak wavelength of the light output from the laminated film 37 (that is, transmitted through the laminated film 37) can be changed by changing the effective refractive index without changing the resonator length of the resonator 51. It will be possible.

The structure shown in FIG. 5 can also be applied to the resonator 51 (metamaterial layer 44) of the present embodiment. That is, the metamaterial layer 44 of the present embodiment may have a structure in which a plurality of amorphous silicon portions 46a are embedded in the silicon oxide portion 41a.

FIG. 46 is a graph for explaining the characteristics of the solid-state image sensor of the ninth embodiment.

FIG. 46A shows the characteristics of the solid-state image sensor of the comparative example of the ninth embodiment, and more specifically, shows the quantum efficiency when the color filter layer 38 is not provided on the laminated film 37. FIG. 46B shows the characteristics of the solid-state image sensor of the ninth embodiment, and specifically shows the quantum efficiency when the color filter layer 38 is provided on the laminated film 37. In A of FIG. 46, a higher-order mode peak is seen near 800 nm, but in B of FIG. 46, this higher-order mode peak is suppressed. As described above, according to the present embodiment, it is possible to realize a single mode without performing the signal processing as described above.

According to the present embodiment, by forming the resonator 51 on the compound semiconductor substrate 29 including the InGaAs substrate 29a and the InP layer 29b, a solid-state image sensor having better characteristics than when a silicon substrate is used can be realized. Is possible. For example, it is possible to realize multi-spectroscopy in a long wavelength region as compared with the case of using a silicon substrate. Further, the thickness of the metamaterial layer 44 of the present embodiment is, for example, 20 nm to 100 nm, and according to the present embodiment, it is possible to realize a resonator 51 having a small resonator length.

(10th Embodiment)
FIG. 47 is a graph for explaining the operation of the solid-state image sensor according to the tenth embodiment.

The solid-state image sensor of the present embodiment has the configuration shown in FIG. 1 and the structure shown in FIG. 2, similar to the solid-state image sensor of the first embodiment. In addition, the solid-state image sensor of this embodiment is used in a manner as described with reference to FIG. 47.

FIG. 47 is a graph for explaining an example in which the solid-state imaging device of the present embodiment is applied to an NDVI (Normalized Difference Vegetation Index) such as agriculture and plant cultivation. FIG. 47 shows the spectral characteristics of the reflectance of plants.

From FIG. 47, it can be seen that the reflectance of the plant changes significantly depending on the vegetation state in the wavelength range of 600 to 800 nm (0.6 to 0.8 μm). Specifically, it can be seen that the reflectance of plants differs between healthy plants, weakened plants, and dead plants. This reflectance is mainly derived from the leaves of plants.

According to the result of FIG. 47, if the reflected light from the plant can be acquired at two or more wavelengths in the range of 600 to 800 nm, the vegetation state of the plant can be sensed. Alternatively, if the reflected light from the plant can be acquired at one or more wavelengths in the wavelength range lower than 600 to 800 nm and one or more wavelengths in the wavelength region higher than 600 to 800 nm, the vegetation state of the plant can be detected. become.

For example, the reflected light having a wavelength in the range of 600 to 700 nm is detected by the first detector, the reflected light having a wavelength in the range of 700 to 800 nm is detected by the second detector, and the signal values of these detectors are measured. Vegetation status can be detected by analyzing the relationship. Alternatively, the reflected light having a wavelength in the range of 400 to 600 nm is detected by the first detector, the reflected light having a wavelength in the range of 800 to 1000 nm is detected by the second detector, and the signal values of these detectors are measured. Vegetation status can be detected by analyzing the relationship.

In the present embodiment, a part of the pixel 1 of the solid-state image sensor is used as the first detector, and another part of the pixel 1 of the solid-state image sensor is used as the second detector. It becomes possible to detect the state. Alternatively, two solid-state image sensors may be used as the first and second detectors.

In this embodiment, the reflected light may be acquired at three or more wavelengths in order to improve the detection accuracy of the reflected light. Further, in the present embodiment, the solid-state imaging device may be mounted on a drone (small unmanned helicopter) to observe the growing state of the crop from the sky, and the detection result of the vegetation state of the crop may be utilized for growing the crop.

(11th Embodiment)
FIG. 48 is a graph for explaining the operation of the solid-state image sensor of the eleventh embodiment.

The solid-state image sensor of the present embodiment has the configuration shown in FIG. 1 and the structure shown in FIG. 2, similar to the solid-state image sensor of the first embodiment. In addition, the solid-state image sensor of this embodiment is used in a manner as described with reference to FIG. 48.

FIG. 48 is a graph for explaining an example in which the solid-state image sensor of the present embodiment is applied to biometric authentication. FIG. 48 shows the spectral characteristics of the reflectance of human skin.

From FIG. 48, it can be seen that the reflectance of human skin changes significantly in the wavelength range of 450 to 450 nm for all of Mongoloid, Caucasian, and Negroid. By using such a change, it is possible to authenticate whether or not the subject is human skin. For example, by detecting reflected light having wavelengths of 450 nm, 550 nm, and 650 nm, it is possible to authenticate whether or not the subject is human skin. When the subject is another material other than human skin, the spectral characteristics of its reflectance are different from those of human skin, so that human skin and other materials can be distinguished.

In the present embodiment, one part of the pixel 1 of the solid-state image sensor is used for detecting the reflected light having a wavelength of 450 nm, and another part of the pixel 1 of the solid-state image sensor is used for detecting the reflected light having a wavelength of 550 nm. By using another part of the pixel 1 of the solid-state image sensor for detecting the reflected light having a wavelength of 650 nm, the solid-state image sensor can detect human skin. Alternatively, two or more solid-state image sensors may be used for reflected light detection.

According to the present embodiment, by detecting human skin, it is possible to prevent forgery and fraudulent acts in biometric authentication using faces, fingerprints, irises and the like. For example, when a person uses a fingerprint engraved on rubber for fingerprint authentication, the spectral characteristic of the reflectance of rubber is different from the spectral characteristic of the reflectance of human skin, so that the person's fraud is discovered. It becomes possible. This enables more accurate biometric authentication.

(Application example)
FIG. 49 is a block diagram showing a configuration example of an electronic device. The electrical device shown in FIG. 49 is the camera 100.

The camera 100 includes an optical unit 101 including a lens group and the like, an image pickup device 102 which is a solid-state image pickup device according to any one of the first to eleventh embodiments, and a DSP (Digital Signal Processor) circuit 103 which is a camera signal processing circuit. , A frame memory 104, a display unit 105, a recording unit 106, an operation unit 107, and a power supply unit 108. Further, the DSP circuit 103, the frame memory 104, the display unit 105, the recording unit 106, the operation unit 107, and the power supply unit 108 are connected to each other via the bus line 109.

The optical unit 101 captures incident light (image light) from the subject and forms an image on the image pickup surface of the image pickup apparatus 102. The image pickup apparatus 102 converts the amount of incident light imaged on the image pickup surface by the optical unit 101 into an electric signal in pixel units, and outputs the light amount as a pixel signal.

The DSP circuit 103 performs signal processing on the pixel signal output by the image pickup apparatus 102. The frame memory 104 is a memory for storing one screen of a moving image or a still image captured by the imaging device 102.

The display unit 105 includes a panel-type display device such as a liquid crystal panel or an organic EL panel, and displays a moving image or a still image captured by the image pickup device 102. The recording unit 106 records a moving image or a still image captured by the imaging device 102 on a recording medium such as a hard disk or a semiconductor memory.

The operation unit 107 issues operation commands for various functions of the camera 100 under the operation of the user. The power supply unit 108 appropriately supplies various power sources that serve as operating power sources for the DSP circuit 103, the frame memory 104, the display unit 105, the recording unit 106, and the operation unit 107 to these supply targets.

By using the solid-state image pickup device according to any one of the first to eleventh embodiments as the image pickup device 102, good image acquisition can be expected.

The solid-state image sensor can be applied to various other products. For example, the solid-state imaging device may be mounted on various moving objects such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, and robots.

FIG. 50 is a block diagram showing a configuration example of a mobile control system. The mobile control system shown in FIG. 50 is a vehicle control system 200.

The vehicle control system 200 includes a plurality of electronic control units connected via the communication network 201. In the example shown in FIG. 50, the vehicle control system 200 includes a drive system control unit 210, a body system control unit 220, an external information detection unit 230, an in-vehicle information detection unit 240, and an integrated control unit 250. There is. FIG. 50 further shows a microcomputer 251, an audio image output unit 252, and an in-vehicle network I / F (Interface) 253 as components of the integrated control unit 250.

The drive system control unit 210 controls the operation of the device related to the drive system of the vehicle according to various programs. For example, the drive system control unit 210 includes a driving force generator for generating a driving force of a vehicle such as an internal combustion engine and a driving motor, a driving force transmission mechanism for transmitting the driving force to wheels, and a steering wheel of the vehicle. It functions as a control device such as a steering mechanism that adjusts the angle and a braking device that generates braking force for the vehicle.

The body system control unit 220 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 220 functions as a control device such as a smart key system, a keyless entry system, a power window device, and various lamps (for example, a head lamp, a back lamp, a brake lamp, a winker, and a fog lamp). In this case, the body system control unit 220 may be input with radio waves transmitted from a portable device that substitutes for the key or signals of various switches. The body system control unit 220 receives such an input of radio waves or signals and controls a vehicle door lock device, a power window device, a lamp, and the like.

The vehicle outside information detection unit 230 detects information outside the vehicle equipped with the vehicle control system 200. For example, an imaging unit 231 is connected to the vehicle exterior information detection unit 230. The vehicle exterior information detection unit 230 causes the image pickup unit 231 to capture an image of the outside of the vehicle, and receives the captured image from the image pickup unit 231. The vehicle exterior information detection unit 230 may perform object detection processing or distance detection processing such as a person, a vehicle, an obstacle, a sign, or a character on a road surface based on the received image.

The imaging unit 231 is an optical sensor that receives light and outputs an electric signal according to the amount of the light received. The image pickup unit 231 can output an electric signal as an image or can output it as distance measurement information. The light received by the imaging unit 231 may be visible light or invisible light such as infrared light. The image pickup unit 231 includes the solid-state image pickup device according to any one of the first to eleventh embodiments.

The vehicle interior information detection unit 240 detects information inside the vehicle equipped with the vehicle control system 200. For example, a driver state detection unit 241 that detects the driver's state is connected to the vehicle interior information detection unit 240. For example, the driver state detection unit 241 includes a camera that images the driver, and the in-vehicle information detection unit 240 has a degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 241. May be calculated, or it may be determined whether or not the driver is dozing. This camera may include the solid-state image sensor according to any one of the first to eleventh embodiments, and may be, for example, the camera 100 shown in FIG. 49.

The microcomputer 251 calculates a control target value of the driving force generator, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside information detection unit 230 or the inside information detection unit 240, and controls the drive system. A control command can be output to the unit 210. For example, the microcomputer 251 is a coordinated control for the purpose of realizing ADAS (Advanced Driver Assistance System) functions such as vehicle collision avoidance, impact mitigation, follow-up running based on inter-vehicle distance, vehicle speed maintenance running, collision warning, and lane deviation warning. It can be performed.

Further, the microcomputer 251 controls the driving force generator, the steering mechanism, or the braking device based on the information around the vehicle acquired by the vehicle exterior information detection unit 230 or the vehicle interior information detection unit 240, so that the driver can control the driver. It is possible to perform coordinated control for the purpose of automatic driving that runs autonomously without depending on the operation.

Further, the microcomputer 251 can output a control command to the body system control unit 220 based on the information outside the vehicle acquired by the vehicle exterior information detection unit 230. For example, the microcomputer 251 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the external information detection unit 230, and performs cooperative control for the purpose of anti-glare such as switching the high beam to the low beam. It can be carried out.

The audio-image output unit 252 transmits an output signal of at least one of audio and image to an output device capable of visually or audibly notifying the passenger of the vehicle or the outside of the vehicle. In the example of FIG. 50, an audio speaker 261, a display unit 262, and an instrument panel 263 are shown as such output devices. The display unit 262 may include, for example, an onboard display or a heads-up display.

FIG. 51 is a plan view showing a specific example of the set position of the imaging unit 231 of FIG. 50.

The vehicle 300 shown in FIG. 51 includes imaging units 301, 302, 303, 304, and 305 as imaging units 231. The imaging units 301, 302, 303, 304, and 305 are provided at positions such as the front nose, side mirrors, rear bumpers, back doors, and the upper part of the windshield in the vehicle interior of the vehicle 300, for example.

The imaging unit 301 provided in the front nose mainly acquires an image in front of the vehicle 300. The image pickup unit 302 provided on the left side mirror and the image pickup section 303 provided on the right side mirror mainly acquire an image of the side of the vehicle 300. The image pickup unit 304 provided on the rear bumper or the back door mainly acquires an image of the rear of the vehicle 300. The image pickup unit 305 provided on the upper part of the windshield in the vehicle interior mainly acquires an image in front of the vehicle 300. The imaging unit 305 is used, for example, to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

FIG. 51 shows an example of the imaging range of the imaging units 301, 302, 303, 304 (hereinafter referred to as “imaging units 301 to 304”). The imaging range 311 indicates the imaging range of the imaging unit 301 provided on the front nose. The imaging range 312 indicates the imaging range of the imaging unit 302 provided on the left side mirror. The imaging range 313 indicates the imaging range of the imaging unit 303 provided on the right side mirror. The imaging range 314 indicates the imaging range of the imaging unit 304 provided on the rear bumper or the back door. For example, by superimposing the image data captured by the imaging units 301 to 304, a bird's-eye view image of the vehicle 300 viewed from above can be obtained. Hereinafter, the imaging range 311, 312, 313, 314 will be referred to as "imaging range 31 to 314".

At least one of the imaging units 301 to 304 may have a function of acquiring distance information. For example, at least one of the imaging units 301 to 304 may be a stereo camera including a plurality of imaging devices, or an imaging device having pixels for detecting a phase difference.

For example, the microcomputer 251 (FIG. 50) is based on the distance information obtained from the imaging units 301 to 304, the distance to each three-dimensional object within the imaging range 31 to 314, and the temporal change of this distance (vehicle 300). Relative velocity with respect to) is calculated. Based on these calculation results, the microcomputer 251 is the closest three-dimensional object on the traveling path of the vehicle 300, and is a three-dimensional object traveling at a predetermined speed (for example, 0 km / h or more) in almost the same direction as the vehicle 300. , Can be extracted as a preceding vehicle. Further, the microcomputer 251 can set an inter-vehicle distance to be secured in front of the preceding vehicle in advance, and can perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. As described above, according to this example, it is possible to perform coordinated control for the purpose of automatic driving or the like in which the vehicle autonomously travels without being operated by the driver.

For example, the microcomputer 251 classifies three-dimensional object data related to a three-dimensional object into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, electric poles, and other three-dimensional objects based on the distance information obtained from the imaging units 301 to 304. It can be extracted and used for automatic avoidance of obstacles. For example, the microcomputer 251 identifies obstacles around the vehicle 300 into obstacles that can be seen by the driver of the vehicle 300 and obstacles that are difficult to see. Then, the microcomputer 251 determines the collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, the microcomputer 251 is used via the audio speaker 261 or the display unit 262. By outputting an alarm to the driver and performing forced deceleration and avoidance steering via the drive system control unit 210, driving support for collision avoidance can be provided.

At least one of the imaging units 301 to 304 may be an infrared camera that detects infrared rays. For example, the microcomputer 251 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured image of the imaging units 301 to 304. Such pedestrian recognition is, for example, whether or not a pedestrian is a pedestrian by performing a procedure for extracting feature points in an image captured by an imaging unit 301 to 304 as an infrared camera and a pattern matching process on a series of feature points indicating the outline of an object. It is performed by the procedure for determining. When the microcomputer 251 determines that a pedestrian is present in the captured images of the imaging units 301 to 304 and recognizes the pedestrian, the audio image output unit 252 has a square contour line for emphasizing the recognized pedestrian. The display unit 262 is controlled so as to superimpose and display. Further, the audio image output unit 252 may control the display unit 262 so as to display an icon or the like indicating a pedestrian at a desired position.

Although the embodiments of the present disclosure have been described above, these embodiments may be implemented with various modifications without departing from the gist of the present disclosure. For example, two or more embodiments may be combined and implemented.

The present disclosure may also have the following structure.

(1)
Photoelectric conversion unit and
The fabric pero resonator provided on the photoelectric conversion unit and
A filter layer provided on the fabric pero resonator or between the fabric pero resonator and the photoelectric conversion unit, and
A sensor device equipped with.

(2)
Photoelectric conversion unit and
A resonator provided on the photoelectric conversion unit and including a metamaterial layer, and
A filter layer provided on the resonator or between the resonator and the photoelectric conversion unit,
With
The metamaterial layer includes a first portion formed of the first material and a plurality of second portions formed of a second material different from the first material and provided in the first portion.
Sensor device.

(3)
One of the first and second materials is an insulating material containing silicon.
The other of the first and second materials is an insulating material or a semiconductor material containing silicon.
The sensor device according to (2).

(4)
The sensor device according to (2), further comprising a semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer.

(5)
A semiconductor layer other than the semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer is not provided between the metamaterial layer and the substrate including the metamaterial layer and the photoelectric conversion unit (4). ).

(6)
The sensor device according to (4), wherein the semiconductor layer is a silicon layer.

(7)
The sensor device according to (2), wherein the resonator includes the metamaterial layer and an insulating film in contact with the upper surface or the lower surface of the metamaterial layer.

(8)
The sensor device according to (7), wherein the insulating film is formed of the first or second material.

(9)
The resonator is provided in a laminated film provided on the photoelectric conversion unit.
The filter layer is provided on the laminated film or between the laminated film and the photoelectric conversion unit.
The laminated film includes a first layer provided on the photoelectric conversion unit, the resonator provided on the first layer, and a second layer provided on the resonator (2). ).

(10)
The sensor device according to (9), wherein at least one of the first and second layers includes one or more insulating films and / or one or more semiconductor layers.

(11)
The sensor device according to (2), wherein the refractive index of the second material is different from the refractive index of the first material.

(12)
The sensor device according to (2), wherein the peak wavelength of the light transmitted through the resonator changes according to the effective refractive index of the resonator.

(13)
The sensor device according to (2), wherein the effective refractive index of the resonator is set based on the image height of the sensor device.

(14)
Further provided with a lens provided on the resonator
The sensor device according to (2), wherein the planar shape of the lens is asymmetric with respect to the center of the lens.

(15)
The sensor device according to (2), wherein the resonator is provided on a compound semiconductor substrate including the photoelectric conversion unit.

(16)
The compound semiconductor substrate includes an InGaAs (indium gallium arsenide) layer and an InP (indium phosphide) layer provided on the InGaAs layer.
The resonator is provided on the InP layer.
The sensor device according to (15).

(17)
The resonator length of the resonator is λ / n or more (λ represents the peak wavelength of the light output from the resonator in vacuum, and n represents the effective refractive index of the resonator). The sensor device according to (2).

(18)
The sensor device according to (2), wherein the resonator length of the resonator is 700 nm / n or more (n represents the effective refractive index of the resonator).

(19)
The resonator including the metamaterial layer including the first portion formed of the first material and the plurality of second portions formed of the second material and provided in the first portion. When,
A second resonator comprising a second portion formed of the second material and a second metamaterial layer formed of the first material and comprising a plurality of first portions provided within the second portion. When,
The sensor device according to (2).

(20)
The sensor device according to (2), wherein the sensor device reduces the number of modes of light by transmitting multimode light through the filter layer and the resonator.

(21)
The sensor device according to (2), wherein the sensor device converts multi-mode spectroscopy into single-mode spectroscopy by signal processing.

(22)
2. The sensor device according to (2), wherein the sensor device transmits multimode light through the filter layer and the resonator to generate single mode light having a peak wavelength in the wavelength range of near infrared light. Sensor device.

(23)
The sensor device according to (2), wherein the sensor device is a solid-state imaging device including a pixel array region having a plurality of pixels.

(24)
The sensor device according to (23), wherein the pixel array region has a periodic array in units of n × n (n is an integer of 2 or more) pixels.

(25)
Form a photoelectric conversion part,
A fabric pero resonator is formed on the photoelectric conversion unit, and the fabric cavity resonator is formed.
A filter layer is formed on the fabric pero resonator or between the fabric pero resonator and the photoelectric conversion unit.
A method of manufacturing a sensor device including that.

(26)
Form a photoelectric conversion part,
A resonator including a metamaterial layer is formed on the photoelectric conversion unit.
A filter layer is formed on the resonator or between the resonator and the photoelectric conversion unit.
Including that
The metamaterial layer includes a first portion formed of the first material and a plurality of second portions formed of a second material different from the first material and provided in the first portion.
Manufacturing method of sensor device.

(27)
The metamaterial layer is
Forming the first portion formed of the first material,
The plurality of second portions formed of the second material are embedded in the first portion.
The method for manufacturing a sensor device according to (26), which is formed by the above.

1: Pixel, 2: Pixel array area, 3: Control circuit,
4: Vertical drive circuit, 5: Column signal processing circuit, 6: Horizontal drive circuit,
7: Output circuit, 8: Vertical signal line, 9: Horizontal signal line,
11: Support substrate, 12, 13, 14: Wiring layer,
15: interlayer insulating film, 16: gate electrode, 17: gate insulating film,
21: Substrate, 22: Photoelectric converter, 23: P-type semiconductor region, 24: n-type semiconductor region,
25: p-type semiconductor region, 26: pixel separation layer, 27: p-well layer, 28: floating diffusion part,
29: Compound semiconductor substrate, 29a: InGaAs layer, 29b: InP layer,
31: groove, 32: element separation part, 33: fixed charge film, 34: insulating film, 35: light-shielding film,
36: Flattening film, 37: Laminated film, 38: Color filter layer,
39: On-chip lens, 39a: low refractive index portion, 39b: high refractive index portion,
41: Silicon oxide film, 41a: Silicon oxide portion,
42: Silicon nitride film, 42a: Silicon nitride portion,
43: polysilicon layer, 44: metamaterial layer, 45: antireflection film,
46: Amorphous silicon layer, 46a: Amorphous silicon part,
47: ITO layer, 51: resonator

Claims (27)

Photoelectric conversion unit and
The fabric pero resonator provided on the photoelectric conversion unit and
A filter layer provided on the fabric pero resonator or between the fabric pero resonator and the photoelectric conversion unit, and
A sensor device equipped with. Photoelectric conversion unit and
A resonator provided on the photoelectric conversion unit and including a metamaterial layer, and
A filter layer provided on the resonator or between the resonator and the photoelectric conversion unit,
With
The metamaterial layer includes a first portion formed of the first material and a plurality of second portions formed of a second material different from the first material and provided in the first portion.
Sensor device. One of the first and second materials is an insulating material containing silicon.
The other of the first and second materials is an insulating material or a semiconductor material containing silicon.
The sensor device according to claim 2. The sensor device according to claim 2, further comprising a semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer. A claim that no semiconductor layer other than the semiconductor layer in contact with the upper surface or the lower surface of the metamaterial layer is provided between the metamaterial layer and the substrate including the metamaterial layer and the photoelectric conversion unit. 4. The sensor device according to 4. The sensor device according to claim 4, wherein the semiconductor layer is a silicon layer. The sensor device according to claim 2, wherein the resonator includes the metamaterial layer and an insulating film in contact with the upper surface or the lower surface of the metamaterial layer. The sensor device according to claim 7, wherein the insulating film is formed of the first or second material. The resonator is provided in a laminated film provided on the photoelectric conversion unit.
The filter layer is provided on the laminated film or between the laminated film and the photoelectric conversion unit.
A claim that the laminated film includes a first layer provided on the photoelectric conversion unit, the resonator provided on the first layer, and a second layer provided on the resonator. 2. The sensor device according to 2. The sensor device according to claim 9, wherein at least one of the first and second layers includes one or more insulating films and / or one or more semiconductor layers. The sensor device according to claim 2, wherein the refractive index of the second material is different from the refractive index of the first material. The sensor device according to claim 2, wherein the peak wavelength of the light transmitted through the resonator changes according to the effective refractive index of the resonator. The sensor device according to claim 2, wherein the effective refractive index of the resonator is set based on the image height of the sensor device. Further provided with a lens provided on the resonator
The sensor device according to claim 2, wherein the planar shape of the lens is asymmetric with respect to the center of the lens. The sensor device according to claim 2, wherein the resonator is provided on a compound semiconductor substrate including the photoelectric conversion unit. The compound semiconductor substrate includes an InGaAs (indium gallium arsenide) layer and an InP (indium phosphide) layer provided on the InGaAs layer.
The resonator is provided on the InP layer.
The sensor device according to claim 15. The resonator length of the resonator is λ / n or more (λ represents the peak wavelength of the light output from the resonator in vacuum, and n represents the effective refractive index of the resonator). The sensor device according to claim 2. The sensor device according to claim 2, wherein the resonator length of the resonator is 700 nm / n or more (n represents the effective refractive index of the resonator). The resonator including the metamaterial layer including the first portion formed of the first material and the plurality of second portions formed of the second material and provided in the first portion. When,
A second resonator comprising a second portion formed of the second material and a second metamaterial layer formed of the first material and comprising a plurality of first portions provided within the second portion. When,
The sensor device according to claim 2. The sensor device according to claim 2, wherein the sensor device reduces the number of modes of light by transmitting multimode light through the filter layer and the resonator. The sensor device according to claim 2, wherein the sensor device converts multimode spectroscopy into single-mode spectroscopy by signal processing. The sensor device according to claim 2, wherein the sensor device transmits multimode light through the filter layer and the resonator to generate single mode light having a peak wavelength in the wavelength range of near infrared light. Sensor device. The sensor device according to claim 2, wherein the sensor device is a solid-state imaging device including a pixel array region having a plurality of pixels. The sensor device according to claim 23, wherein the pixel array region has a periodic array in units of n × n (n is an integer of 2 or more) pixels. Form a photoelectric conversion part,
A fabric pero resonator is formed on the photoelectric conversion unit, and the fabric cavity resonator is formed.
A filter layer is formed on the fabric pero resonator or between the fabric pero resonator and the photoelectric conversion unit.
A method of manufacturing a sensor device including that. Form a photoelectric conversion part,
A resonator including a metamaterial layer is formed on the photoelectric conversion unit.
A filter layer is formed on the resonator or between the resonator and the photoelectric conversion unit.
Including that
The metamaterial layer includes a first portion formed of the first material and a plurality of second portions formed of a second material different from the first material and provided in the first portion.
Manufacturing method of sensor device. The metamaterial layer is
Forming the first portion formed of the first material,
The plurality of second portions formed of the second material are embedded in the first portion.
The method for manufacturing a sensor device according to claim 26, which is formed by the above.

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