JP2021136352A - Solid-state imaging device and manufacturing method of same - Google Patents

Abstract

To provide a solid-state imaging device capable of achieving a suitable filter layer and a manufacturing method of the same.SOLUTION: A solid-state imaging device includes a photoelectric conversion unit, a filter layer provided on the photoelectric conversion unit and containing a plurality of metal nanoparticles, and a lens provided on the filter layer.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a solid-state image sensor and a method for manufacturing the same.

In a solid-state imaging device such as a multi-spectral CIS (CMOS image sensor), there is a problem of variation in the process when forming a fabric pero resonator or a propagation type surface plasmon resonance filter as a filter layer. For example, variations in the thickness of the multilayer film and variations in the pore size of the metal film become problems in the plane of the CIS and between lots. In addition, it takes a long time to form the multilayer film of the fabric pero resonator, which is also a problem. Furthermore, since the propagation type surface plasmon resonance filter has a large amount of light reflection on the surface, it is also a problem that flare appears when a strong light such as sunlight is imaged. Due to these problems, mass production of CIS including a fabric pero resonator and a propagation type surface plasmon resonance filter becomes difficult.

Japanese Unexamined Patent Publication No. 2012-59865 Japanese Unexamined Patent Publication No. 2015-88847

Rongchao Jin et al. “Photoinduced Conversion of Silver Nanospheres to Nanoprisms” Science, p.1901-1903, vol.294, 30 November 2001 Rongchao Jin et al. “Controlling anisotropic nanoparticle growth through plasmon excitation” Nature, p.487-490, vol.425, 2 Octover 2003

Therefore, for solid-state imaging devices such as multi-spectral CIS, the half-value width of filter spectroscopy can be narrowed, the variation in spectral characteristics due to the process can be reduced, the filter layer can be easily formed, and the filter can be used. It is required to reduce the light reflection on the surface of the layer to reduce the flare.

Therefore, the present disclosure provides a solid-state image sensor capable of realizing a suitable filter layer and a method for manufacturing the same.

The solid-state image sensor of the first aspect of the present disclosure includes a photoelectric conversion unit, a filter layer provided on the photoelectric conversion unit and containing a plurality of metal nanoparticles, and a lens provided on the filter layer. .. This makes it possible to realize a suitable filter layer, for example, a filter layer having good performance can be easily formed.

Further, on the first side surface, the metal nanoparticles may have a plate-like shape. This makes it possible to narrow the half width of filter spectroscopy, for example.

Also, in this first aspect, the metal nanoparticles may include silver, aluminum, gold, copper, or tantalum. This makes it possible to realize, for example, a localized plasmon filter.

Further, in the first aspect, the metal nanoparticles may be randomly arranged in the filter layer. This makes it possible to uniformly distribute the metal nanoparticles, for example, over the entire filter layer.

Further, in this first aspect, the filter layer may function as a localized plasmon filter. This makes it possible to realize a plasmon filter having a method different from that of the propagation type plasmon filter.

Further, the solid-state imaging device on the first side surface passes, as the filter layer, a first wavelength filter layer that passes or blocks light of the first wavelength and light of a second wavelength different from the first wavelength. Alternatively, it may be provided with a second wavelength filter layer for blocking. This makes it possible to use, for example, a filter layer as a color filter.

Further, in the first aspect, the shape of the metal nanoparticles in the second wavelength filter layer may be different from the shape of the metal nanoparticles in the first wavelength filter layer. This makes it possible to realize color filters of different colors, for example, depending on the shape of the metal nanoparticles.

Further, in the first aspect, even if the diameter or aspect ratio of the metal nanoparticles in the second wavelength filter layer is different from the diameter or aspect ratio of the metal nanoparticles in the first wavelength filter layer. good. This makes it possible to realize color filters of different colors, for example, depending on the difference in the diameter and aspect ratio of the metal nanoparticles.

Further, the solid-state image sensor on the first side surface applies an electric field to the filter layer by the first and second electrodes sandwiching the filter layer and the first and second electrodes to form the metal nanoparticles. It may be further provided with an electric field application unit for changing the above. This makes it possible, for example, to change the wavelength of light that passes through the filter layer or is blocked by the filter layer by an electric field.

Further, on the first side surface, the first and second electrodes may be transparent electrodes provided on the lower surface and the upper surface of the filter layer. This makes it possible to stack and arrange the first electrode, the filter layer, and the second electrode.

Further, in the first aspect, the filter layer may be an electrolyte layer containing the metal nanoparticles. This makes it possible to change the shape of the metal nanoparticles, for example, by ionizing the metal atoms in the metal nanoparticles.

Further, in the first aspect, the electrolyte layer may be a gel layer. This makes it possible to easily handle the electrolyte layer.

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

Further, in this first aspect, the filter layer may function as a complementary color filter. This makes it possible to obtain complementary color signal values for each pixel.

Further, the solid-state image sensor on the first side surface is provided on the second photoelectric conversion unit and the second photoelectric conversion unit, and is provided on the second filter layer containing no metal nanoparticles and on the second filter layer. The difference between the signal value from the second pixel corresponding to the second filter layer and the signal value from the first pixel corresponding to the filter layer functioning as the complementary color filter, which further includes the provided second lens. May be used to calculate the signal value of the primary color in the first pixel. This makes it possible to obtain the signal values of the primary colors in each pixel.

Further, in the first aspect, the solid-state image sensor may be provided in the camera. This makes it possible to realize, for example, a multi-spectral camera.

In the method for manufacturing a solid-state image sensor according to the second aspect of the present disclosure, a photoelectric conversion unit is formed, a filter layer containing a plurality of metal nanoparticles is formed on the photoelectric conversion unit, and a lens is placed on the filter layer. Including forming. This makes it possible to realize a suitable filter layer, for example, a filter layer having good performance can be easily formed.

In this second aspect, the filter layer may be formed by applying a material in which metal nanoparticles are dispersed and processing the material. This makes it possible to easily form the filter layer by the coating method.

In the second aspect, the filter layer may be formed by applying a photosensitive resin material in which metal nanoparticles are dispersed and processing the photosensitive resin material by lithography. This makes it possible to easily form the filter layer by a general method of the semiconductor manufacturing process.

In the method of manufacturing the solid-state imaging device on the second side surface, as the filter layer, a first wavelength filter layer that allows light of the first wavelength to pass through and a second wavelength filter layer that allows light of a second wavelength different from the first wavelength to pass through. It may include forming the wavelength filter layer in order. This makes it possible to use, for example, a filter layer as a color filter.

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 a perspective view which shows the shape of the metal nanoparticle of 1st Embodiment. It is a figure for demonstrating the characteristic of the color filter layer of 1st Embodiment. It is a graph for demonstrating the characteristic of the color filter layer of 1st Embodiment. It is another graph for demonstrating the characteristic of the color filter layer of 1st Embodiment. It is sectional drawing (1/4) which shows the manufacturing method of the solid-state image sensor of 1st Embodiment. It is sectional drawing (2/4) which shows the manufacturing method of the solid-state image sensor of 1st Embodiment. It is sectional drawing (3/4) which shows the manufacturing method of the solid-state image sensor of 1st Embodiment. It is sectional drawing (4/4) which shows the manufacturing method 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 3rd Embodiment. It is a graph for demonstrating the operation of the solid-state image sensor of 4th Embodiment. It is a graph for demonstrating the operation of the solid-state image sensor of 5th Embodiment. It is a graph for demonstrating the operation of the solid-state image sensor of 6th 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 processes. 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.

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-by-row direction 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 imaging device 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 imaging device of the present embodiment further includes a groove 31, an element separation unit 32 provided in the groove 31, a fixed charge film (film having a negative fixed charge) 33 and an insulating film included in the element separation unit 32. It includes 34, a light-shielding film 35, a flattening film 36, a plurality of color filter layers 37, a plurality of metal nanoparticles 38 contained in each color filter layer 37, and a plurality of on-chip lenses 39.

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 37 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 37, 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 color filter layer 37 is formed on the flattening film 36 for each pixel 1. For example, the color filter layers 37 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 37 for yellow (Y), magenta (M), and cyan (C) are arranged above the photoelectric conversion unit 22 of the yellow, magenta, and cyan pixels 1, respectively. Further, these color filter layers 37 may include a color filter layer 37 for infrared light above the photoelectric conversion unit 22 of the infrared light (IR) pixel 1. Each color filter layer 37 has a property that light of a predetermined wavelength can or cannot be transmitted, and the light transmitted through each color filter layer 37 passes through the insulating film 34 and the fixed charge film 33 to the photoelectric conversion unit 22. Incident in.

The metal nanoparticles 38 are included in the color filter layer 37. The metal nanoparticles 38 are metal fine particles having nanoscale (less than 1 μm) dimensions. For example, when the shape of the metal nanoparticles 38 is spherical, the metal nanoparticles 38 have a diameter of less than 1 μm. FIG. 2 shows, as an example, metal nanoparticles 38a contained in the color filter layer 37 for yellow, metal nanoparticles 38b contained in the color filter layer 37 for magenta, and metal contained in the color filter layer 37 for cyan. It shows nanoparticles 38c. The metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c of the present embodiment have different shapes (sizes) from each other. Further details of the metal nanoparticles 38 will be described later.

The on-chip lens 39 is formed on the color filter layer 37 for each pixel 1. Each on-chip lens 39 has a property of condensing the 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 37 or the like. do.

The support substrate 11 is provided on the front side of the substrate 21 via an interlayer insulating film 15, and is provided 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 is incident on the photoelectric conversion unit 22 via the color filter layer 37, the flattening film 36, the insulating film 34, and the fixed charge film 33. 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.

Next, further details of the metal nanoparticles 38 of the present embodiment will be described.

FIG. 3 is a perspective view showing the shape of the metal nanoparticles 38 of the first embodiment.

The metal nanoparticles 38 of the present embodiment have a triangular prism shape, and more specifically, have a triangular plate-like shape. FIG. 3 shows the length L of one side of the triangle and the thickness T of the plate. In the present embodiment, the thickness T is shorter than the length L (T <L), and the length L is less than 1 μm. For example, the thickness T is 5 nm to 20 nm and the length L is 10 nm to 100 nm.

The metal nanoparticles 38 of the present embodiment are silver (Ag) particles. When silver is crystallized, it has the property of forming metal nanoparticles 38 having a triangular plate-like shape. Therefore, in the present embodiment, by crystallizing silver, metal nanoparticles 38 having a triangular plate-like shape can be formed.

The metal nanoparticles 38 of the present embodiment may be metal particles other than silver particles, and may be, for example, aluminum (Al) particles, gold (Au) particles, copper (Cu) particles, or tantalum (Ta) particles. Further, the shape of the metal nanoparticles 38 of the present embodiment may be other than a triangular prism, and may be, for example, a square prism, a cylinder, or a sphere.

The color filter layer 37 (FIG. 2) of the present embodiment is formed by applying a material in which a plurality of metal nanoparticles 38 are dispersed to the entire surface of the substrate 21 and processing the material into the shape of the color filter layer 37. .. This makes it possible to easily form the color filter layer 37 containing the metal nanoparticles 38 by the coating method. More specifically, in the color filter layer 37 of the present embodiment, a photosensitive resin material in which a plurality of metal nanoparticles 38 are dispersed is applied to the upper surface of the flattening film 36, and the photosensitive resin material is processed by lithography. Is formed. This makes it possible to easily form the color filter layer 37 containing the metal nanoparticles 38 by a general method of a semiconductor manufacturing process such as a coating method, lithography, or etching. The material for dispersing the metal nanoparticles 38 is preferably a transparent material, for example. This allows, for example, light from the on-chip lens 39 to pass through the material.

When the color filter layer 37 is formed by such a method, the metal nanoparticles 38 are randomly arranged in the color filter layer 37. For example, the density of the metal nanoparticles 38 in the color filter layer 37 becomes substantially uniform in the color filter layer 37.

As described above, in the present embodiment, the color filter layer 37 is selectively formed on each pixel 1 by applying a material in which a plurality of metal nanoparticles 38 are dispersed and processing the material. This makes it possible to realize a color filter layer 37 that functions as a localized plasmon filter, and enables multi-spectral spectroscopy using this localized plasmon filter.

Here, the localized plasmon resonance is a plasmon resonance that occurs on the surface of metal particles having a particle size of submicron order to nano order. When a plurality of metal particles having a substantially uniform particle size are present, these metal particles selectively absorb, reflect, or scatter light of a specific wavelength by localized plasmon resonance. Therefore, according to the present embodiment, by dispersing a plurality of metal nanoparticles 38 in a material such as a photosensitive resin material, this material can function as a color filter layer 37 utilizing plasmon resonance. Become.

4 and 5 are diagrams and graphs for explaining the characteristics of the color filter layer 37 of the first embodiment. FIG. 4 shows Ag particles present in the dielectric, for example, metal nanoparticles 38 present in the color filter layer 37. FIG. 5 shows the relationship between the particle size and the peak wavelength of absorbance when the particle size of the plurality of Ag particles existing in the dielectric is uniform. According to FIG. 5, these Ag particles absorb light of a specific wavelength, and the value of this specific wavelength is in the order of A, B, C, D, E, F according to the particle size of the Ag particles. It can be seen that it changes with. That is, these Ag particles show different spectra depending on the particle size. The peak wavelength in FIG. 5 changes substantially linearly with a change in particle size.

This mechanism is as follows. When the metal particles are irradiated with light of a specific wavelength, the light resonates on the surface of the metal particles to generate a localized electromagnetic field. This is the localized plasmon. Light that does not resonate passes through the metal particles.

The light transmission spectrum at this time tends to be a complementary color filter as shown in FIG. FIG. 6 is another graph for explaining the characteristics of the color filter layer 37 of the first embodiment. FIG. 6 shows the spectrum of the light transmitted through the above-mentioned dielectric, for example, the spectrum of the light transmitted through the color filter layer 37. This light does not have a maximum point (mountain) at a certain wavelength, but has a minimum point (valley) at a certain wavelength. This indicates that this dielectric is more suitable for complementary color filters such as yellow, magenta, or cyan filters than primary color filters such as red, green, or blue filters. In the present embodiment, further, signal processing may be performed to obtain a spectrum having a narrow half-value width of the peak from this spectroscopy.

Metallic materials in which such localized plasmons are generated are, for example, silver (Ag), aluminum (Al), gold (Au), copper (Cu), tantalum (Ta) and the like. Therefore, the metal nanoparticles 38 of the present embodiment are formed using such a metal. Since the color filter layer 37 of the present embodiment is formed by using a metal, it is excellent in light resistance as compared with a general organic filter using a pigment or a dye.

According to this embodiment, it is possible to realize a color filter layer 37 that functions as a localized plasmon filter instead of a propagation plasmon filter. Propagation-type plasmon filters are formed, for example, by providing a plurality of dielectric portions in a bulk metal, whereas localized plasmon filters are formed, for example, by providing a plurality of metal portions in a bulk dielectric. .. In the present embodiment, these metal portions are realized by a plurality of metal nanoparticles 38.

Next, with reference to FIGS. 2 and 3, further details of the metal nanoparticles 38 of the present embodiment will be described.

The metal nanoparticles 38 of the present embodiment have a triangular prism shape, and more specifically, have a triangular plate-like shape (FIG. 3). FIG. 3 shows the length L of one side of the triangle and the thickness T of the plate. Making the shape of the metal nanoparticles 38 plate-like has the advantages that, for example, the wavelength selectivity of the color filter layer 37 can be improved and the half-value width of the filter spectroscopy can be narrowed.

FIG. 2 shows, as an example, metal nanoparticles 38a contained in the color filter layer 37 for yellow, metal nanoparticles 38b contained in the color filter layer 37 for magenta, and metal contained in the color filter layer 37 for cyan. It shows nanoparticles 38c. The particle size of the metal nanoparticles 38a of the present embodiment is set to be substantially uniform in order to generate localized plasmon resonance. Similarly, the particle size of the metal nanoparticles 38b of the present embodiment is set to be substantially uniform, and the particle size of the metal nanoparticles 38c of the present embodiment is also set to be substantially uniform.

On the other hand, the metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c of the present embodiment have different particle diameters (sizes) from each other. For example, the aspect ratio (ratio L / T of length L to thickness T) of each metal nanoparticles 38 is a small value for the metal nanoparticles 38a, a medium value for the metal nanoparticles 38b, and a medium value for the metal nanoparticles 38c. It is set to a large value. As a result, different spectra can be obtained between the color filter layer 37 containing the metal nanoparticles 38a, the color filter layer 37 containing the metal nanoparticles 38b, and the color filter layer 37 containing the metal nanoparticles 38c. That is, these color filter layers 37 can function as color filters of different colors.

Each color filter layer 37 of the present embodiment has a property of passing or blocking light having a predetermined wavelength, and more specifically, has a property of absorbing light having a predetermined wavelength. Therefore, in the present embodiment, each color filter layer 37 can function as a complementary color filter such as a yellow, magenta, or cyan filter. Each color filter layer 37 of the present embodiment can block light having a predetermined wavelength in a form of absorbing light. In FIG. 2, the light incident on the color filter layer 37, the light transmitted through the color filter layer 37, and the light absorbed (or reflected) by the color filter layer 37 are indicated by arrows. Each color filter layer 37 may block light having a predetermined wavelength in the form of reflecting light, or may pass light having a predetermined wavelength instead of blocking it. The color filter layer 37 that allows light of a predetermined wavelength to pass through can function as a primary color filter such as a red, green, or blue filter, for example. Any two of the three types of color filter layers 37 of the present embodiment are examples of the first wavelength filter and the second wavelength filter of the present disclosure.

The wavelength of light absorbed by each color filter layer 37 of the present embodiment depends on the length L of the metal nanoparticles 38. Therefore, the metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c of the present embodiment have different lengths L from each other. On the other hand, the metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c of the present embodiment have substantially the same thickness T. Therefore, the metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c of the present embodiment have different aspect ratios L / T.

Generally speaking, the wavelength of light absorbed by each color filter layer 37 depends on the particle size of the metal nanoparticles 38. In this case, the metal nanoparticles 38a, the metal nanoparticles 38b, and the metal nanoparticles 38c are formed so as to have different particle diameters from each other. When the shape of the metal nanoparticles 38 is a sphere, the particle size of the metal nanoparticles 38 is the diameter of the metal nanoparticles 38. When the shape of the metal nanoparticles 38 is other than a sphere, the particle diameter of the metal nanoparticles 38 is the diameter of the metal nanoparticles 38 when the shape of the metal nanoparticles 38 is regarded as a sphere. For example, when the shape of the metal nanoparticles 38 is a triangular plate, the particle diameter of the metal nanoparticles 38 is close to the length L of the metal nanoparticles 38.

7 to 10 are cross-sectional views showing a method of manufacturing the solid-state image sensor of the first embodiment.

First, as shown in A of FIG. 7, 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, a pixel transistor such as a photoelectric conversion unit 22 and a transfer transistor Tr1 is formed. Next, as shown in A of FIG. 7, 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. 7 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 B of FIG. 7, 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. 7B 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 B of FIG. 7, 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. 8, 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 B of FIG. 8, 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 B of FIG. 8, a flattening film 36 is formed on the insulating film 34 via a light-shielding film 35, and a color filter layer 37a containing a plurality of metal nanoparticles 38a is formed on the flattening film 36. To form. The color filter layer 37a is, for example, a photosensitive organic material (for example, a resin) in which metal nanoparticles 38a are dispersed, and is formed by applying the photosensitive organic material on the upper surface of the flattening film 36. The thickness of the color filter layer 37a is controlled by, for example, spin coating.

Next, as shown in FIG. 9A, the color filter layer 37a is exposed and developed by lithography, and the shape of the color filter layer 37a is etched. As a result, the color filter layer 37a containing the metal nanoparticles 38a remains only on the yellow pixel 1 and is removed from the other regions.

Next, as shown in B of FIG. 9, the color filter layer 37b is formed and processed in the same manner as the color filter layer 37a. The color filter layer 37b is, for example, a photosensitive organic material (for example, a resin) in which metal nanoparticles 38b are dispersed, and is formed by applying the photosensitive organic material to the upper surfaces of the flattening film 36 and the color filter layer 37a. NS. After that, the color filter layer 37b is exposed and developed by lithography and etched. As a result, the color filter layer 37b containing the metal nanoparticles 38b remains only on the magenta pixel 1 and is removed from the other regions.

Next, as shown in FIG. 10A, the color filter layer 37c is formed and processed in the same manner as the color filter layer 37a. The color filter layer 37c is, for example, a photosensitive organic material (for example, a resin) in which metal nanoparticles 38c are dispersed, and the photosensitive organic material is applied to the flattening film 36, the color filter layer 37a, and the upper surface of the color filter layer 37b. It is formed by applying. After that, the color filter layer 37c is exposed and developed by lithography and etched. As a result, the color filter layer 37c containing the metal nanoparticles 38c remains only on the cyan pixel 1 and is removed from the other regions.

In this way, the color filter layers 37a, 37b, and 37c are formed in order, and the plurality of color filter layers 37 shown in FIG. 2 are formed.

Next, as shown in B of FIG. 10, a plurality of on-chip lenses 39 are formed on these color filter layers 37 by etch back. In this way, the solid-state image sensor shown in FIG. 2 is manufactured.

As described above, each color filter layer 37 of the present embodiment contains a plurality of metal nanoparticles 38. Therefore, according to the present embodiment, it is possible to realize a suitable color filter layer 37, for example, the color filter layer 37 having good performance can be easily formed.

For example, by making the shape of the metal nanoparticles 38 into a plate shape, it is possible to narrow the half width of the filter spectroscopy. Further, since the color filter layer 37 is a complementary color filter which is a filter having less light reflection, flare can be reduced. Further, by manufacturing the color filter layer 37 in the steps from B to A in FIG. 8 to reduce the variation in the spectral characteristics due to the process, it is possible to easily form the color filter layer 37. It will be possible. By applying the color filter layer 37 of the present embodiment to a filter for multi-spectroscopy, it is possible to realize a solid-state image sensor having good spectral characteristics with wavelength separation and a camera provided with such a solid-state image sensor. .. For example, the solid-state image sensor of the present embodiment can be applied to agriculture to evaluate the vegetation state, or can be applied to biological recognition to detect a biological part such as human skin to obtain highly accurate information. be able to.

(Second Embodiment)
FIG. 11 is a cross-sectional view showing the structure of the solid-state image sensor of the second embodiment.

The solid-state image sensor of FIG. 11 includes a lower electrode 41, a plurality of upper electrodes 42, and an electric field application unit 43 in addition to the components shown in FIG.

The lower electrode 41 is provided on the lower surface of the plurality of color filter layers 37, and functions as a common electrode of these color filter layers 37. On the other hand, each upper electrode 42 is provided on the upper surface of the corresponding color filter layer 37, and functions as an individual electrode of the color filter layer 37. The lower electrode 41 and the upper electrode 42 of the present embodiment are, for example, transparent electrodes formed of ITO (indium tin oxide) or ZnO (zinc oxide). Therefore, in the present embodiment, since light can pass through the upper electrode 42 and the lower electrode 41, the lower electrode 41, the color filter layer 37, and the upper electrode 42 can be laminated and arranged on the flattening film 36. The lower electrode 41 and the upper electrode 42 are examples of the first electrode and the second electrode of the present disclosure.

The lower electrode 41 and the upper electrode 42 may be replaced with other electrodes arranged so as to sandwich the color filter layer 37. For example, the lower electrode 41 and the upper electrode 42 are replaced with a first side electrode provided on the first side surface of the color filter layer 37 and a second side electrode provided on the second side surface of the color filter layer 37. You may. In this case, the first side electrode and the second side electrode may be non-transparent electrodes.

The electric field application unit 43 applies an electric field to each color filter layer 37 by applying an electric field between the lower electrode 41 and each upper electrode 42. Thereby, the shape of the metal nanoparticles 38 in each color filter layer 37 can be changed. The reason why the shape of the metal nanoparticles 38 changes will be described later. According to the present embodiment, by applying an electric field to the color filter layer 37, it is possible to change the wavelength of light passing through the color filter layer 37 or blocked by the color filter layer 37 by the electric field, and electrochromism. Can be realized. The electric field application unit 43 is, for example, a voltage control unit.

Hereinafter, further details of the metal nanoparticles 38 of the present embodiment will be described.

In the present embodiment, by applying a voltage to the color filter layer 37, the particle size of the metal nanoparticles (Ag particles) 38 can be changed, and the transmission spectrum of the color filter layer 37 can be changed. Therefore, it is possible to realize spectroscopy of an arbitrary wavelength in each pixel 1.

The particle size of the metal nanoparticles 38 changes in the process of ^{dissolving Ag +} ions from the metal nanoparticles 38 and ^{the process of electrodeposition of Ag + ions on the metal nanoparticles 38.} For example, when the lower electrode 41 is set to a negative potential, the particle size of the metal nanoparticles 38 increases. On the contrary, when the upper electrode 42 is set to a positive potential, the particle size of the metal nanoparticles 38 decreases. By utilizing these phenomena, the particle size of the metal nanoparticles 38 can be arbitrarily changed.

The color filter layer 37 of the present embodiment is an electrolyte layer containing a plurality of metal nanoparticles 38, but it is difficult to handle the color filter layer 37 if the electrolyte layer is a liquid. Therefore, it is desirable to gel this electrolyte. Therefore, the electrolyte layer of the present embodiment is a gel layer. _{For example, silver nitrate (AgNO 3} ) is dissolved in a solvent of DMSO (dimethyl sulfoxide) to form a base electrolyte, and a supporting electrolyte (for example, LiBr or CuCl ₂ ) is added to this electrolyte. Further, PVB (polyvinyl butyral) is mixed with this electrolyte as a gelling agent. In this way, the color filter layer 37 of the gel electrolyte layer is formed.

It is desirable to provide a wall between the color filter layers 37, that is, between the gel electrolyte layers. As a result, the influence of the adjacent filter on each filter can be reduced, and the controllability of the particle size of the metal nanoparticles 38 can be improved.

As described above, in the solid-state image sensor of the present embodiment, an electric field is applied to the color filter layer 37 by the electric field application unit 43. Therefore, according to the present embodiment, the particle size of the metal nanoparticles 38 can be changed by an electric field, and the transmission spectroscopy of the color filter layer 37 can be changed.

(Third Embodiment)
FIG. 12 is a schematic view showing the structure of the solid-state image sensor of the third 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 pixel array region 2 of the solid-state image sensor of the present embodiment has the structure shown in FIG.

In FIG. 12, 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 contain metal nanoparticles 38 having different particle sizes. 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 biological 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.

(Fourth Embodiment)
FIG. 13 is a graph for explaining the operation of the solid-state image sensor of the fourth 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 the present embodiment operates in a manner as described with reference to FIG.

The pixel array region 2 of the present embodiment includes a normal pixel and a W (white) pixel as the pixel 1. The color filter layer 37 of a normal pixel contains a plurality of metal nanoparticles 38 and functions as a complementary color filter that absorbs light of a specific wavelength. Therefore, the light that passes through the color filter layer 37 of the normal pixel is, for example, yellow light, magenta light, or cyan light. On the other hand, the W pixel color filter layer 37 does not contain the metal nanoparticles 38 and does not function as a color filter. Therefore, the light passing through the W pixel is, for example, white light. The normal pixel and the W pixel are examples of the first pixel and the second pixel of the present disclosure, respectively. The W pixel photoelectric conversion unit 22, the color filter layer 37, and the on-chip lens 39 are examples of the second photoelectric conversion unit, the second filter layer, and the second lens of the present disclosure, respectively.

FIG. 13 shows an example of the spectroscopy of W pixels and the spectroscopy of ordinary pixels (filter pixels). The solid-state imaging device of the present embodiment performs a matrix operation of subtracting the spectral signal value of each normal pixel from the spectral signal value of the W pixel. As shown in FIG. 13, the spectroscopy obtained by this subtraction is equivalent to the spectroscopy obtained by the primary color filter. For example, according to the present embodiment, it is possible to calculate the signal values of red light, green light, and blue light from the detection results of yellow light, magenta light, and cyan light. In the present embodiment, the spectral signal value of each normal pixel is a complementary color signal value, but the difference between the spectral value of the W pixel and the spectral signal value of each normal pixel is used. Therefore, the signal values of the primary colors in each normal pixel can be obtained. The matrix calculation for calculating the signal value of the primary color from the signal value of the complementary color is performed by, for example, an calculation circuit (not shown) provided after the output circuit 7 in FIG.

As described above, according to the present embodiment, by using the W pixel spectroscopy, it is possible to easily and accurately obtain the spectroscopy of the primary color filter, and it is possible to realize highly accurate multi-spectral spectroscopy.

(Fifth Embodiment)
FIG. 14 is a graph for explaining the operation of the solid-state image sensor of the fifth 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.

FIG. 14 is a graph for explaining an example in which the solid-state image sensor of the present embodiment is applied to an NDVI (Normalized Difference Vegetation Index) such as agriculture and plant cultivation. FIG. 14 shows the spectral characteristics of the reflectance of plants.

From FIG. 14, 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. 14, 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, a solid-state image sensor 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.

(Sixth Embodiment)
FIG. 15 is a graph for explaining the operation of the solid-state image sensor of the sixth 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.

FIG. 15 is a graph for explaining an example in which the solid-state image sensor of the present embodiment is applied to biometric authentication. FIG. 15 shows the spectral characteristics of the reflectance of human skin.

From FIG. 15, 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 pixel 1 of the solid-state image sensor is used for detecting the reflected light having a wavelength of 450 nm, and another 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. 16 is a block diagram showing a configuration example of an electronic device. The electrical device shown in FIG. 16 is a 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 sixth 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 sixth 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. 17 is a block diagram showing a configuration example of a mobile control system. The mobile control system shown in FIG. 17 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. 17, 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. 17 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 for a smart key system, a keyless entry system, a power window device, various lamps (for example, a head lamp, a back lamp, a brake lamp, a blinker, a fog lamp) and the like. 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 exterior information detection unit 230 detects information outside the vehicle equipped with the vehicle control system 200. For example, an image pickup 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 sixth 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 sixth embodiments, and may be, for example, the camera 100 shown in FIG.

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 vehicle exterior information detection unit 230 or the vehicle interior 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. 17, as such an output device, an audio speaker 261 and a display unit 262, and an instrument panel 263 are shown. The display unit 262 may include, for example, an onboard display or a heads-up display.

FIG. 18 is a plan view showing a specific example of the set position of the imaging unit 231 of FIG.

The vehicle 300 shown in FIG. 18 includes imaging units 301, 302, 303, 304, and 305 as the imaging unit 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 imaging 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. 18 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. 17) 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 brake 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 microphone 261 or the display unit 262 is used. 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
A filter layer provided on the photoelectric conversion unit and containing a plurality of metal nanoparticles,
With the lens provided on the filter layer,
A solid-state image sensor.

(2)
The solid-state image sensor according to (1), wherein the metal nanoparticles have a plate-like shape.

(3)
The solid-state imaging device according to (1), wherein the metal nanoparticles include silver, aluminum, gold, copper, or tantalum.

(4)
The solid-state image sensor according to (1), wherein the metal nanoparticles are randomly arranged in the filter layer.

(5)
The solid-state image sensor according to (1), wherein the filter layer functions as a localized plasmon filter.

(6)
The filter layer includes a first wavelength filter layer that allows or blocks light of the first wavelength, and a second wavelength filter layer that allows or blocks light of a second wavelength different from the first wavelength. The solid-state imaging device according to 1).

(7)
The solid-state imaging device according to (6), wherein the shape of the metal nanoparticles in the second wavelength filter layer is different from the shape of the metal nanoparticles in the first wavelength filter layer.

(8)
The solid-state imaging device according to (7), wherein the diameter or aspect ratio of the metal nanoparticles in the second wavelength filter layer is different from the diameter or aspect ratio of the metal nanoparticles in the first wavelength filter layer.

(9)
The first and second electrodes sandwiching the filter layer,
An electric field application portion that changes the shape of the metal nanoparticles by applying an electric field to the filter layer by the first and second electrodes.
The solid-state image sensor according to (1).

(10)
The solid-state image sensor according to (9), wherein the first and second electrodes are transparent electrodes provided on the lower surface and the upper surface of the filter layer.

(11)
The solid-state image sensor according to (9), wherein the filter layer is an electrolyte layer containing the metal nanoparticles.

(12)
The solid-state image sensor according to (11), wherein the electrolyte layer is a gel layer.

(13)
The solid-state image sensor according to (1), wherein the pixel array region of the solid-state image sensor has a periodic array in units of n × n (n is an integer of 2 or more) pixels.

(14)
The solid-state image sensor according to (1), wherein the filter layer functions as a complementary color filter.

(15)
The second photoelectric conversion unit and
A second filter layer provided on the second photoelectric conversion unit and containing no metal nanoparticles,
A second lens provided on the second filter layer is further provided.
Using the difference between the signal value from the second pixel corresponding to the second filter layer and the signal value from the first pixel corresponding to the filter layer functioning as the complementary color filter, the primary color in the first pixel is used. The solid-state imaging device according to (14), which calculates a signal value.

(16)
The solid-state image sensor according to (1), wherein the solid-state image sensor is provided in a camera.

(17)
Form a photoelectric conversion part,
A filter layer containing a plurality of metal nanoparticles is formed on the photoelectric conversion unit, and the filter layer is formed.
A lens is formed on the filter layer.
A method of manufacturing a solid-state image sensor including the above.

(18)
The method for manufacturing a solid-state image sensor according to (17), wherein the filter layer is formed by applying a material in which metal nanoparticles are dispersed and processing the material.

(19)
The method for manufacturing a solid-state image sensor according to (18), wherein the filter layer is formed by applying a photosensitive resin material in which metal nanoparticles are dispersed and processing the photosensitive resin material by lithography.

(20)
As the filter layer, a first wavelength filter layer that allows light of the first wavelength to pass through and a second wavelength filter layer that allows light of a second wavelength different from the first wavelength to pass through are sequentially formed (17). ). The method for manufacturing a solid-state imaging device.

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,
31: groove, 32: element separation part, 33: fixed charge film, 34: insulating film, 35: light-shielding film,
36: Flattening film, 37, 37a, 37b, 37c: Color filter layer,
38, 38a, 38b, 38c: metal nanoparticles, 39: on-chip lens,
41: Lower electrode, 42: Upper electrode, 43: Electric field application part

Claims (20)

Photoelectric conversion unit and
A filter layer provided on the photoelectric conversion unit and containing a plurality of metal nanoparticles,
With the lens provided on the filter layer,
A solid-state image sensor. The solid-state image sensor according to claim 1, wherein the metal nanoparticles have a plate-like shape. The solid-state imaging device according to claim 1, wherein the metal nanoparticles include silver, aluminum, gold, copper, or tantalum. The solid-state image sensor according to claim 1, wherein the metal nanoparticles are randomly arranged in the filter layer. The solid-state image sensor according to claim 1, wherein the filter layer functions as a localized plasmon filter. Claimed claim that the filter layer includes a first wavelength filter layer that allows or blocks light of the first wavelength, and a second wavelength filter layer that allows or blocks light of a second wavelength different from the first wavelength. Item 2. The solid-state imaging device according to item 1. The solid-state imaging device according to claim 6, wherein the shape of the metal nanoparticles in the second wavelength filter layer is different from the shape of the metal nanoparticles in the first wavelength filter layer. The solid-state imaging device according to claim 7, wherein the diameter or aspect ratio of the metal nanoparticles in the second wavelength filter layer is different from the diameter or aspect ratio of the metal nanoparticles in the first wavelength filter layer. The first and second electrodes sandwiching the filter layer,
An electric field application portion that changes the shape of the metal nanoparticles by applying an electric field to the filter layer by the first and second electrodes.
The solid-state image sensor according to claim 1. The solid-state image sensor according to claim 9, wherein the first and second electrodes are transparent electrodes provided on the lower surface and the upper surface of the filter layer. The solid-state image sensor according to claim 9, wherein the filter layer is an electrolyte layer containing the metal nanoparticles. The solid-state image sensor according to claim 11, wherein the electrolyte layer is a gel layer. The solid-state image sensor according to claim 1, wherein the pixel array region of the solid-state image sensor has a periodic array in units of n × n (n is an integer of 2 or more) pixels. The solid-state image sensor according to claim 1, wherein the filter layer functions as a complementary color filter. The second photoelectric conversion unit and
A second filter layer provided on the second photoelectric conversion unit and containing no metal nanoparticles,
A second lens provided on the second filter layer is further provided.
Using the difference between the signal value from the second pixel corresponding to the second filter layer and the signal value from the first pixel corresponding to the filter layer functioning as the complementary color filter, the primary color in the first pixel is used. The solid-state imaging device according to claim 14, which calculates a signal value. The solid-state image sensor according to claim 1, wherein the solid-state image sensor is provided in a camera. Form a photoelectric conversion part,
A filter layer containing a plurality of metal nanoparticles is formed on the photoelectric conversion unit, and the filter layer is formed.
A lens is formed on the filter layer.
A method of manufacturing a solid-state image sensor including the above. The method for manufacturing a solid-state image sensor according to claim 17, wherein the filter layer is formed by applying a material in which metal nanoparticles are dispersed and processing the material. The method for manufacturing a solid-state imaging device according to claim 18, wherein the filter layer is formed by applying a photosensitive resin material in which metal nanoparticles are dispersed and processing the photosensitive resin material by lithography. The claim includes, as the filter layer, sequentially forming a first wavelength filter layer that allows light of the first wavelength to pass through and a second wavelength filter layer that allows light of a second wavelength different from the first wavelength to pass through. 17. The method for manufacturing a solid-state imaging device according to 17.

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