JP7316340B2 - Solid-state imaging device and electronic equipment - Google Patents

Description

The present technology relates to solid-state imaging devices. Specifically, the present invention relates to a solid-state imaging device and an electronic device having an antireflection layer on a light receiving surface.

A CMOS image sensor using crystalline silicon for light absorption has high sensitivity from visible wavelengths to infrared rays, but is generally optimized to have high sensitivity at green wavelengths in accordance with the sensitivity of the human eye. For example, the color array of an RGB sensor is a 2×2 unit pixel array in which two pixels are green and the rest are red and blue. There is also an anti-reflection coating between the silicon substrate and the top layer, which is optimized to reduce green reflection. The anti-reflection coating implemented on top of the sensor pixels of an image sensor is typically a simple λ/4 waveplate. Therefore, for example, when optimized to suppress green reflection, sufficient antireflection effects cannot be obtained at blue and red wavelengths, and large reflection components at ultraviolet and infrared wavelengths cause image quality such as reduced sensitivity and flare ghosts. There was a problem of causing deterioration. For this reason, for example, a solid-state imaging device has been proposed in which a fine concave-convex structure is provided at the interface on the light-receiving surface side of a silicon layer in which a photodiode is formed (see Patent Document 1 and Non-Patent Document 1, for example).

JP 2015-029054 A

Yokogawa, Sozo, et al. "IR sensitivity enhancement of CMOS Image Sensor with diffractive light trapping pixels." Scientific Reports 7 (2017)

In the prior art described above, by providing a fine uneven structure at the interface on the light receiving surface side of the silicon layer, the reflection of incident light is prevented and the sensitivity is improved. However, in this case, light is diffracted within the silicon due to the concave-convex structure. For example, for pixels with long wavelength components, such as red and infrared rays, in which the light absorption coefficient of silicon is small, the diffracted light mixes with adjacent pixels, resulting in poor color reproduction. degradation of image quality and spatial resolution.

The present technology has been developed in view of such circumstances, and aims to improve both the sensitivity and the resolution of an imaging element in a wide wavelength band.

The present technology has been made to solve the above-described problems, and a first aspect thereof is that each pixel arranged two-dimensionally is provided for one of at least three different wavelength bands. and anti-reflection provided on the light-receiving surface of the pixel that receives the light incident through the color filter, and further comprising a periodic concave-convex structure for some of the at least three types. A solid-state imaging device and an electronic device comprising a layer. This has the effect of diffracting incident light for some types of wavelength bands.

In the first aspect, the color filter may correspond to any three or more of infrared, red, green, blue, ultraviolet, and achromatic color as the at least three different wavelength bands. .

Further, in this first aspect, the color filters are arranged according to a Bayer array, the antireflection layer has a flat film structure for pixels in which the color filters are green filters, and the color filters are blue filters. A pixel may be provided with the above-described periodic concave-convex structure. This provides an effect of diffracting incident light for the pixels of the blue filter and at the same time acts as an antireflection layer for the blue component. As a result, the sensitivity is improved as compared to pixels with conventional blue filters.

Further, in the first aspect, the antireflection layer may have the periodic concave-convex structure even for pixels in which the color filter is a red filter. As a result, the pixels of the red filter also have an effect of diffracting incident light, and at the same time, an effect of an antireflection layer for the red component is brought about. As a result, there is a sensitivity enhancement effect compared to a pixel with a conventional red filter.

Further, in the first aspect, the periodic concave-convex structure may be a structure in which inverted pyramid structures composed of silicon crystal planes (111) are periodically arranged. In this case, the angle formed by the inverted pyramid structure with respect to the silicon substrate surface may be arctan(2 ^1/2 ) of the arctangent function. Also, the distance between adjacent pyramids in the inverted pyramid structure and the length of each side of the inverted pyramid structure may be 200 nm to 800 nm, more preferably 400 nm to 600 nm. Also, the number of pyramids in the inverted pyramid structure may be an integral number for each pixel.

In the first aspect, the antireflection layer includes a reflector made of a λ/4 wavelength plate for pixels whose color filters are green filters, and for pixels whose color filters are ultraviolet or blue filters. may comprise a structure in which the inverted pyramid structure is periodically arranged. As a result, the structure in which the inverted pyramid structure is periodically arranged for the pixels of the ultraviolet or blue filter has the effect of diffracting the incident light, and at the same time has the effect of an antireflection layer for the same wavelength component. As a result, the sensitivity is improved as compared with conventional pixels.

Moreover, in this first aspect, the antireflection layer may have a structure in which the inverted pyramid structure is periodically arranged even for pixels in which the color filter is a red filter. As a result, the pixels of the red filter also have the effect of diffracting the incident light and at the same time functioning as an antireflection layer for the same wavelength component. As a result, the sensitivity is improved as compared with conventional pixels.

Further, in the first aspect, the device further includes a photoelectric conversion section that converts light received by each pixel into a voltage signal, and an element isolation section that separates the photoelectric conversion section for each pixel. The portion may comprise a structure in which a trench structure is carved into the silicon substrate. This provides an effect of separating the photoelectric conversion units for each pixel.

Further, in the first aspect, the element isolation portion may be formed by filling the trench structure with a metal material, and the metal material may be tungsten, aluminum, copper, or a metal alloy thereof. It may be used as a main component. This brings about the effect of shielding the diffracted light and suppressing the optical color mixture.

Further, in this first aspect, the phase difference detection pixel having one on-chip condensing structure in adjacent 2 × 1 pixels or 2 × 2 pixels is further provided, and the antireflection layer is the phase difference detection pixel may have a flat membrane structure. As a result, there is an effect that the phase difference detection pixel does not have a periodic concave-convex structure.

According to the present technology, it is possible to achieve an excellent effect of being able to achieve both improvement in sensitivity and improvement in resolution of an imaging element in a wide wavelength band. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is a figure showing an example of composition of a solid imaging device in an embodiment of this art. It is a figure showing an example of arrangement of a solid-state imaging device in an embodiment of this art. It is a figure showing an example of circuit composition of pixel 11 in an embodiment of this art. It is an example of a top view of a semiconductor substrate of a pixel in an embodiment of this art. It is an example of a sectional view of a pixel in a 1st embodiment of this art. It is a figure which shows the 1st example of arrangement|positioning of the color filter 320 and the antireflection layer in 1st Embodiment of this technique. It is a figure which shows the 2nd example of arrangement|positioning of the color filter 320 and the antireflection layer in 1st Embodiment of this technique. It is a figure showing an example of periodic concavo-convex structure in an embodiment of this art. It is a figure showing other examples of periodic concavo-convex structure in an embodiment of this art. It is a figure which shows the pixel classification for demonstrating the characteristic of the image structure in embodiment of this technique. FIG. 11 is a diagram showing characteristics versus wavelength for the three pixel types 710, 720 and 730 of FIG. 10; It is an example of a sectional view of a pixel in a 2nd embodiment of this art. It is a figure showing an example of arrangement of a color filter 320 and an antireflection layer in a 2nd embodiment of this art. It is an example of a sectional view of a pixel in a 3rd embodiment of this art. It is a figure which shows the 1st example of arrangement|positioning of the color filter 320 and the antireflection layer in 3rd Embodiment of this technique. It is a figure which shows the 2nd example of arrangement|positioning of the color filter 320 and the antireflection layer in 3rd Embodiment of this technique. It is a figure which shows the 3rd example of arrangement|positioning of the color filter 320 and the antireflection layer in 3rd Embodiment of this technique. It is a figure which shows the 4th example of arrangement|positioning of the color filter 320 and the antireflection layer in 3rd Embodiment of this technique. It is a figure showing an example of composition of imaging device 80 which is an example of application of an embodiment of this art. It is a figure showing an example of appearance of personal digital assistant 70 which is an example of application of an embodiment of this art. It is a figure showing an example of a field to which an embodiment of this art is applied. 1 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which technology according to the present disclosure may be applied; FIG. 12A and 12B are diagrams illustrating an example of an installation position of an imaging unit 12031; FIG. 1 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which technology according to the present disclosure can be applied; FIG. 25 is a block diagram showing an example of functional configurations of a camera head 11102 and a CCU 11201 shown in FIG. 24; FIG.

Hereinafter, a form for carrying out the present technology (hereinafter referred to as an embodiment) will be described. Explanation will be given in the following order.
1. First Embodiment (Example in which uneven structure is provided only for blue pixels)
2. Second Embodiment (Example in which red pixels are also provided with an uneven structure)
3. Third Embodiment (An example in which the phase difference detection pixel is not provided with a concave-convex structure)
4. Application example

<1. First Embodiment>
[Configuration of solid-state imaging device]
FIG. 1 is a diagram illustrating a configuration example of a solid-state imaging device according to an embodiment of the present technology. This solid-state imaging device comprises a pixel region 10 and a peripheral circuit section. The peripheral circuit section includes a vertical drive circuit 20 , a horizontal drive circuit 30 , a control circuit 40 , a column signal processing circuit 50 and an output circuit 60 .

The pixel region 10 is a pixel array in which a plurality of pixels 11 including photoelectric conversion units are arranged in a two-dimensional array. The pixel 11 includes, for example, a photodiode serving as a photoelectric conversion unit and a plurality of pixel transistors. Here, the plurality of pixel transistors can be composed of, for example, four transistors: a transfer transistor, a reset transistor, a selection transistor, and an amplification transistor.

The vertical drive circuit 20 drives the pixels 11 on a row-by-row basis. This vertical driving circuit 20 is configured by, for example, a shift register. The vertical drive circuit 20 selects a pixel drive wiring and supplies pulses for driving the pixels 11 to the selected pixel drive wiring. As a result, the vertical drive circuit 20 sequentially selectively scans the pixels 11 in the pixel region 10 row by row in the vertical direction, and generates pixel signals based on the signal charges generated by the photoelectric conversion units of the pixels 11 according to the amount of light received. is supplied to the column signal processing circuit 50 via the vertical signal line 19 .

The horizontal drive circuit 30 drives the column signal processing circuit 50 for each column. This horizontal driving circuit 30 is configured by, for example, a shift register. The horizontal driving circuit 30 sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 50 in turn, and the pixel signals from each of the column signal processing circuits 50 are sent via the horizontal signal line 59 to Output to the output circuit 60 .

The control circuit 40 controls the entire solid-state imaging device. This control circuit 40 receives an input clock and data instructing an operation mode and the like, and outputs data such as internal information of the solid-state imaging device. That is, the control circuit 40 generates a clock signal and a control signal that serve as a reference for the operation of the vertical driving circuit 20, the column signal processing circuit 50, the horizontal driving circuit 30, etc. based on the vertical synchronizing signal, the horizontal synchronizing signal, and the master clock. Generate. These signals are input to the vertical drive circuit 20, the column signal processing circuit 50, the horizontal drive circuit 30, and the like.

The column signal processing circuit 50 is arranged for each column of the pixels 11, for example, and performs signal processing such as noise removal on signals output from the pixels 11 of one row for each pixel column. That is, the column signal processing circuit 50 performs signal processing such as CDS (Correlated Double Sampling) for removing fixed pattern noise unique to the pixels 11, signal amplification, and AD (Analog to Digital) conversion. A horizontal selection switch (not shown) is connected between the output stage of the column signal processing circuit 50 and the horizontal signal line 59 .

The output circuit 60 performs signal processing on the signals sequentially supplied from each of the column signal processing circuits 50 through the horizontal signal line 59 and outputs the processed signals. At that time, this output circuit 60 buffers the signal from the column signal processing circuit 50 . Further, the output circuit 60 may perform black level adjustment, column variation correction, various digital signal processing, etc. on the signal from the column signal processing circuit 50 .

FIG. 2 is a diagram illustrating an arrangement example of solid-state imaging devices according to the embodiment of the present technology.

When the solid-state imaging device is arranged as a non-stacked type, as shown by a in FIG. A logic circuit 93 for processing is arranged on one substrate.

As shown in b and c in the figure, when the solid-state imaging device is arranged as a stacked type, several division examples are conceivable. b in the same figure shows the 1st example of division|segmentation. In this first division example, a pixel region 91 and a control region 92 are mounted on the first semiconductor chip. A logic circuit 93 is mounted on the second semiconductor chip. A solid-state imaging device is configured by electrically connecting the first semiconductor chip and the second semiconductor chip to each other.

c in the same figure shows the second example of division. In this second division example, a pixel region 91 is mounted on the first semiconductor chip. A control area 92 and a logic circuit 93 are mounted on the second semiconductor chip. A solid-state imaging device is configured by electrically connecting the first semiconductor chip and the second semiconductor chip to each other.

[Pixel circuit configuration]
FIG. 3 is a diagram showing a circuit configuration example of the pixel 11 according to the embodiment of the present technology.

The pixel 11 includes a photodiode 17 , a transfer transistor 12 , a floating diffusion region 13 , a reset transistor 14 , an amplification transistor 15 and a selection transistor 16 . These four transistors, the transfer transistor 12, the reset transistor 14, the amplification transistor 15 and the selection transistor 16, are called pixel transistors. In this example, it is assumed that the pixel transistor is a MOS transistor whose carrier polarity is N-type.

For the pixels 11, three signal lines, a transfer signal line, a reset signal line, and a selection signal line, are provided in the row direction, and vertical signal lines 19 are provided in the column direction. A power supply voltage Vdd is supplied to the drain sides of the reset transistor 14 and the amplification transistor 15 .

A photodiode (PD) 17 is a photoelectric conversion unit that generates an electric charge according to incident light. The anode of this photodiode 17 is grounded.

The transfer transistor 12 is a transistor that transfers charges generated in the photodiode 17 . This transfer transistor 12 is provided between the cathode of the photodiode 17 and the floating diffusion region 13 . The transfer transistor 12 is turned on when a high-level signal is input to its gate from the vertical drive circuit 20 via the transfer signal line, and the charge photoelectrically converted in the photodiode 17 is transferred to the floating diffusion region 13 . do.

A floating diffusion (FD) region 13 is a diffusion region that converts the charge transferred by the transfer transistor 12 into a voltage signal. A voltage signal of this floating diffusion region 13 is connected to the drain of the reset transistor 14 and the gate of the amplification transistor 15 .

The reset transistor 14 is a transistor for resetting the voltage of the floating diffusion region 13 . This reset transistor 14 is provided between the power supply voltage Vdd and the floating diffusion region 13 . The reset transistor 14 is turned on when a high-level signal is input from the vertical drive circuit 20 to its gate to the reset signal line, and resets the potential of the floating diffusion region 13 to the power supply voltage Vdd.

The amplification transistor 15 is a transistor that amplifies the voltage signal of the floating diffusion region 13 . The gate of this amplification transistor 15 is connected to the floating diffusion region 13 . The drain of the amplification transistor 15 is connected to the power supply voltage Vdd, and the source of the amplification transistor 15 is connected to the vertical signal line 19 via the selection transistor 16 . The amplification transistor 15 amplifies the voltage signal of the floating diffusion region 13 and outputs the amplified signal to the selection transistor 16 as a pixel signal.

A selection transistor 16 is a transistor for selecting this pixel. This selection transistor 16 is provided between the amplification transistor 15 and the vertical signal line 19 . The selection transistor 16 is turned on when a high-level signal is input from the vertical drive circuit 20 to its gate to the selection signal line, and outputs the voltage signal amplified by the amplification transistor 15 to the vertical signal line 19 .

[Pixel structure]
FIG. 4 is an example of a plan view of a semiconductor substrate of a pixel according to the embodiment of the present technology; In the embodiments of the present technology, a structure is assumed in which four pixels share one floating diffusion region or the like, and another four pixels are arranged in the vertical direction. However, this structure is an example, and the present technology can be applied to other pixel structures.

In this example, each pixel has a photodiode 170 and a transfer gate 120 , and four pixels share one floating diffusion region 130 , reset transistor 140 and amplification transistor 150 .

The photodiode 170 and floating diffusion region 130 have functions similar to those of the photodiode 17 and floating diffusion region 13 . Also, the transfer gate 120, the reset transistor 140 and the amplification transistor 150 have the same functions as the transfer transistor 12, the reset transistor 14 and the amplification transistor 15 in the circuit example described above. Note that the photodiode 170 and the floating diffusion region 130 are an example of the photoelectric conversion section described in the claims.

FIG. 5 is an example of a cross-sectional view of a pixel according to the first embodiment of the present technology. The figure shows a cross section along AB in the plan view of FIG. 4, and extends over three pixels. Here, as an example, a back-illuminated solid-state imaging device is assumed.

On the back surface of the semiconductor substrate 100, as an optical system, an on-chip lens 310 is provided for each pixel arranged two-dimensionally. Light enters through this on-chip lens 310 . The on-chip lens 310 is made of, for example, a resin material such as styrene resin, acrylic resin, styrene-acrylic copolymer resin, or siloxane resin.

Below the on-chip lens 310, a color filter 320 is provided for each two-dimensionally arranged pixel. This color filter 320 is an on-chip color filter that passes different types of wavelength bands for each pixel. In this example, a Bayer arrangement is assumed, and in this cross section, from the left, they are arranged to pass the wavelength bands of blue (B), green (G), and red (R). ing. The color filter 320 is formed, for example, by spin-coating a photosensitive resin containing dyes such as pigments and dyes. This color filter 320 may generally correspond to one of at least three different wavelength bands. For example, it is configured with three or more filters selected from infrared, red, green, blue, ultraviolet, and achromatic colors. Here, the achromatic filter is a filter that passes the entire visible and near-infrared wavelength band.

Below the color filter 320, a light shielding film 340 for separating pixels is formed on the semiconductor substrate 100 in the pixel boundary region. The light shielding film 340 may be made of any material that blocks light, such as tungsten (W), aluminum (Al), or copper (Cu). A planarization layer 330 is formed between the color filter 320 and the semiconductor substrate 100 . As the material of the planarizing film 330, for example, an organic material such as resin can be used.

The inside of the semiconductor substrate 100 is a light absorption layer, and a photodiode 170 is provided in a portion partitioned by the element isolation portion 190 . The photodiode 170 is formed, for example, as an N-type impurity region sandwiched between P-type semiconductor regions in the depth direction of the semiconductor substrate 100 .

The element isolation part 190 has a structure in which a groove structure 191 is carved in the semiconductor substrate 100 which is a silicon substrate. Such a structure is called DTI (Deep Trench Isolation). The trench structure 191 is covered with an oxide film and filled with, for example, a metal material. It is desirable that this metal material has a high light shielding ability to block diffracted light. As such a metal material, for example, tungsten (W), aluminum (Al), copper (Cu), or a metal alloy thereof can be used as a main component. Alternatively, trench structure 191 may be filled with a dielectric, such as SiO ₂ , which has a relatively low refractive index with respect to silicon. Filling with a metal material having a high light shielding ability has the effect of suppressing optical color mixture and improving resolution, but filling with a dielectric may improve sensitivity.

A pixel transistor is provided on the surface of the semiconductor substrate 100 . In the figure, a transfer gate 120, which is one of pixel transistors, is shown. A wiring layer 200 is provided to cover these pixel transistors. The wiring layer 200 is formed such that the wiring 220 is covered with an insulating layer. This wiring 220 can be a multi-layer wiring consisting of a plurality of layers. A support substrate (not shown) is provided on the surface of the wiring layer 200 .

An antireflection layer for preventing reflection of incident light is provided on the light receiving surface of the pixels on the back surface of the semiconductor substrate 100 . In this example, the antireflection layer 112 of the green filter pixel and the antireflection layer 111 of the red filter pixel are reflectors made of λ/4 wavelength plates. This λ/4 wavelength plate is a single layer film having a thickness of a quarter of the wavelength. On the other hand, the antireflection layer 113 of the blue filter pixel has a periodic concave-convex structure. That is, the anti-reflection layer has a periodic concave-convex structure only in the blue filter pixels of the Bayer array color filter 320 .

Arrows in the figure indicate incident light downward and reflected light upward, and the thickness indicates the intensity of each. Since the anti-reflection layer 112 of the green filter pixel is optimized for green, it moderately suppresses the reflection and causes the photodiode 170 to absorb the incident light. On the other hand, the light incident on the antireflection layer 113 of the blue filter pixel is scattered by the periodic concave-convex structure and absorbed by the photodiode 170 .

[Arrangement of antireflection layer]
FIG. 6 is a diagram showing a first arrangement example of the color filter 320 and the antireflection layer according to the first embodiment of the present technology. As described above, the arrangement of the color filters 320 assumes the Bayer arrangement. The antireflection layer has a periodic concave-convex structure only for the blue filter pixels, and the antireflection layer for the other color filter pixels is a reflector made of a λ/4 wavelength plate. Here, although the antireflection layer has the periodic uneven structure only for the pixels of the blue filter, the antireflection layer may have the periodic uneven structure for the pixels of the ultraviolet filter.

FIG. 7 is a diagram illustrating a second arrangement example of the color filter 320 and the antireflection layer according to the first embodiment of the present technology. Also in this example, the arrangement of the color filters 320 is based on the Bayer arrangement. However, in the above-described first arrangement example, each pixel has a different color, but in this second arrangement example, pixels of the same color filter form a Bayer arrangement in units of a plurality of pixels. Although four pixels of 2×2 pixels are used as a unit in this figure, more pixels may be used as a unit.

[Periodical concave-convex structure]
FIG. 8 is a diagram showing an example of a periodic concave-convex structure according to the embodiment of the present technology. Here, as an example of the periodic concavo-convex structure, a structure in which inverted pyramid structures, which are quadrangular pyramid-shaped concave structures, are periodically arranged is shown.

This inverted pyramid structure is composed of the (111) crystal plane of silicon. This (111) plane is represented by the Miller indices. Since the angle θ formed by this inverted pyramid structure with respect to the silicon substrate surface is the (111) plane with respect to the silicon (100) plane,
tan θ = (2 ^1/2 )
holds. therefore,
θ=arctan(2 ^1/2 )≈55 degrees.

Also, the distance between adjacent pyramids in the inverted pyramid structure and the length of each side are 200 nm to 800 nm, more preferably 400 nm to 600 nm. Also, it is desirable that the number of pyramids in the inverted pyramid structure be an integral number for each pixel.

In order to manufacture this inverted pyramid structure, for example, a photoresist is applied onto the P-type semiconductor on the back surface of the semiconductor substrate 100, and the photoresist is patterned by lithography so that recesses are opened. Based on the patterned photoresist, the semiconductor substrate 100 is dry-etched, and then the photoresist is removed. Note that wet etching treatment can be used instead of dry etching treatment.

FIG. 9 is a diagram showing another example of the periodic concave-convex structure according to the embodiment of the present technology. Here, as an example of the periodic concavo-convex structure, a structure in which forward pyramid structures, which are quadrangular pyramid-shaped convex structures, are periodically arranged is shown. Since the shape and size are the inverse of the above example, detailed description is omitted.

[Characteristic]
FIG. 10 is a diagram showing pixel types for explaining characteristics of an image structure according to the embodiment of the present technology. This figure shows the response when the color filter 320 is not provided.

In the figure, a shows a structure as a first pixel type 710 in which the antireflection layer 711 has a periodic concave-convex structure and the trench structure 719 of the isolation portion is not filled with a metal material. In the figure, b shows a structure in which the antireflection layer 721 has a periodic concave-convex structure as the second pixel type 720, and the groove structure 729 of the element isolation portion is filled with a metal material having a high light shielding capability. . In FIG. 7c, as a third pixel type 730, the antireflection layer 731 has a flat reflector made of a λ/4 wavelength plate, and the groove structure 739 of the element isolation portion is not filled with a metal material. showing.

FIG. 11 is a diagram showing characteristics versus wavelength for the three pixel types 710, 720 and 730 of FIG. In the figure, a indicates the sensitivity or quantum efficiency (QE: Quantum Efficiency) of photoelectric conversion for each wavelength. Moreover, b in the same figure shows the reflectance with respect to each wavelength.

In the first pixel type 710, since the antireflection layer 711 has a periodic concave-convex structure, the structure itself has an effect as an antireflection film. Therefore, the sensitivity in the blue and ultraviolet regions is increased, and the reflection in the red and infrared regions is also reduced. In addition, since the diffracted light extends the optical path length in silicon, the sensitivity at infrared wavelengths is improved, but the resolution is degraded.

In the second pixel type 720, similarly to the first pixel type 710, the antireflection layer 721 has a periodic concave-convex structure, so the structure itself has an effect as an antireflection film. Furthermore, since the metal material filled in the groove structure 729 of the element isolation portion absorbs the diffracted light generated by the periodic concave-convex structure, resolution degradation at infrared wavelengths is small.

In the third pixel type 730, the antireflection layer 731 has high sensitivity in the green region and suppresses green reflection, but the reflection in other wavelength regions is large.

By comparing these, it can be seen that the effect of the periodic concave-convex structure is that the sensitivity is mainly improved in the blue and ultraviolet regions by reducing reflection. Also, it can be seen that when the groove structure of the element isolation portion is filled with a metal material, the sensitivity tends to decrease in the red or infrared region due to the influence of absorption. Therefore, if it is desired to increase the sensitivity in the red or infrared region, it is conceivable to fill the trench structure of the element isolation portion with a dielectric.

As described above, according to the first embodiment of the present technology, the reflection in the blue wavelength region is reduced and the sensitivity is improved by making the antireflection layer have a periodic concave-convex structure only for the pixels of the blue filter. be able to. In addition, by filling the groove structure of the element isolation part with a metal material, it is possible to suppress the mixing of diffracted light into adjacent pixels, especially in the pixels on the long wavelength side, where the absorption coefficient of red or infrared rays is small, and improve the color reproducibility. Degradation and degradation of spatial resolution can be avoided.

<2. Second Embodiment>
In the first embodiment described above, the antireflection layer has a periodic concave-convex structure only for the pixels of the blue filter. On the other hand, the second embodiment is different in that the antireflection layer of the red filter pixels also has a periodic concave-convex structure. Since the overall configuration of the solid-state imaging device is the same as that of the first embodiment, detailed description will be omitted.

[Pixel structure]
FIG. 12 is an example of a cross-sectional view of a pixel according to the second embodiment of the present technology; The figure shows a cross section along AB in the plan view of FIG. 4, and extends over three pixels. Also, as in the first embodiment, a back-illuminated solid-state imaging device is assumed.

In the second embodiment, in addition to the antireflection layer 113 of the blue filter pixels, the antireflection layer 111 of the red filter pixels also has a periodic concave-convex structure. The point that the antireflection layer 112 of the pixel of the green filter is a reflector made of a λ/4 wavelength plate is the same as in the above-described first embodiment. It should be noted that this periodic concave-convex structure can employ an inverted pyramid structure, as in the first embodiment described above.

If the antireflection layer 111 of the pixel of the red filter employs a periodic concave-convex structure, optical diffraction due to this periodic concave-convex structure occurs remarkably at red and infrared wavelengths. Accordingly, the light propagates obliquely within the semiconductor substrate 100, and the effective optical path length is extended. As a result, it is possible to achieve high sensitivity at long wavelengths compared to a normal solid-state imaging device with the same thickness.

On the other hand, long-wavelength light with a small absorption coefficient, such as red and infrared rays, is less likely to be absorbed in the light absorption layer, and thus diffracted light is likely to enter neighboring pixels. In this regard, in the embodiment of the present technology, since the groove structure 191 of the element isolation section 190 is filled with a metal material, diffracted light is shielded to avoid deterioration of color reproducibility and deterioration of spatial resolution. can be done.

[Arrangement of antireflection layer]
FIG. 13 is a diagram showing an arrangement example of the color filter 320 and the antireflection layer according to the second embodiment of the present technology. As described above, the arrangement of the color filters 320 assumes the Bayer arrangement. In addition to the blue filter pixels, the red filter pixels also have a periodic uneven structure in the antireflection layer. For the pixels of the green filter, the antireflection layer is a reflector made of a λ/4 wavelength plate.

In this arrangement example, each pixel is arranged in a different color, but as in the second arrangement example of the first embodiment, pixels of the same color filter form a Bayer array in units of a plurality of pixels. may be arranged to

As described above, according to the second embodiment of the present technology, the antireflection layer of the red filter pixel as well as the blue filter pixel has the periodic concave-convex structure. can be reduced to improve sensitivity. In this case, even if there is a high possibility that diffracted light is mixed into adjacent pixels in the pixels of the red filter, the diffracted light is shielded by the metal material filled in the groove structure of the element isolation section, so color reproducibility is improved. Degradation and degradation of spatial resolution can be avoided.

<3. Third Embodiment>
In the first and second embodiments described above, the antireflection layer 112 of the pixel of the green filter is a reflector made of a λ/4 wavelength plate. On the other hand, if only the light absorption coefficient of silicon is taken into consideration, it is conceivable to employ the periodic concave-convex structure also in the antireflection layer 112 of the pixel of the green filter. On the other hand, in recent solid-state imaging devices, it is common for specific pixels to have phase difference detection pixels for an autofocus function. This phase difference detection pixel is a pixel that performs focus determination from the incident direction of light. Generally, some of the green filter pixels have that function. However, when the pixels of the green filter are phase difference detection pixels, crosstalk due to diffracted light leads to characteristic deterioration, so it is desirable not to provide the periodic concave-convex structure. Therefore, in the third embodiment, a structure is adopted in which the periodic concave-convex structure is not provided for the phase difference detection pixels. Since the overall configuration of the solid-state imaging device is the same as that of the first embodiment, detailed description will be omitted.

[Pixel structure]
FIG. 14 is an example of a cross-sectional view of a pixel according to the third embodiment of the present technology; The figure shows a cross section corresponding to AB in the plan view of FIG. 4, and straddles the blue filter pixels and the phase difference detection pixels. Also, as in the first embodiment, a back-illuminated solid-state imaging device is assumed.

In the third embodiment, the antireflection layer 113 of the blue filter pixel has a periodic concave-convex structure. On the other hand, the antireflection layer 114 of the phase difference detection pixel does not have a periodic concave-convex structure, and serves as a reflector made of a λ/4 wavelength plate. Other points are the same as those of the above-described first embodiment.

[Arrangement of antireflection layer]
FIG. 15 is a diagram showing a first arrangement example of the color filter 320 and the antireflection layer according to the third embodiment of the present technology. As described above, the arrangement of the color filters 320 assumes the Bayer arrangement. At the position of the phase difference detection pixel, the on-chip lens 310 is shared by two adjacent pixels. For the blue filter pixels, the antireflection layer has a periodic concave-convex structure. However, even if the pixel position is originally a blue filter, in the case of a phase difference detection pixel, the periodic concave-convex structure is not provided, and a reflector made of a λ/4 wavelength plate is used.

FIG. 16 is a diagram illustrating a second arrangement example of the color filter 320 and the antireflection layer according to the third embodiment of the present technology. In this second arrangement example, the antireflection layer has a periodic concave-convex structure not only for the blue filter pixels but also for the red filter pixels. Note that these first and second arrangement examples are examples in which adjacent 2×1 pixels are provided with one phase difference detection pixel having an on-chip condensing structure.

FIG. 17 is a diagram showing a third arrangement example of the color filter 320 and the antireflection layer according to the third embodiment of the present technology. In this example, a pixel structure that determines the incident direction as a phase difference detection pixel by shielding half of the two pixels of the green filter in any of the 2×2 pixels that are the units of the Bayer array is adopted. there is The antireflection layer has a periodic concave-convex structure only for the pixels of the blue filter, and the antireflection layers of the pixels of the other color filters including the phase difference detection pixels are reflectors made of λ/4 wavelength plates. there is

FIG. 18 is a diagram showing a fourth arrangement example of the color filter 320 and the antireflection layer according to the third embodiment of the present technology. In this fourth arrangement example, the antireflection layer has a periodic concave-convex structure not only for the blue filter pixels but also for the red filter pixels. Note that these third and fourth arrangement examples are examples in which adjacent 2×2 pixels are provided with one phase difference detection pixel having an on-chip condensing structure.

As described above, in the third embodiment of the present technology, the antireflection layer has a periodic concave-convex structure for the blue filter pixel or the blue and red filter pixels, while the phase difference detection pixel has a periodic concave-convex structure. Do not provide an uneven structure. Thereby, crosstalk due to diffracted light can be suppressed, and characteristic deterioration can be avoided.

<4. Application example>
Embodiments of the present technology described above can be applied to various technologies as exemplified below.

[Imaging device]
FIG. 19 is a diagram illustrating a configuration example of an imaging device 80 that is an application example of the embodiment of the present technology. This imaging device 80 includes an optical system configuration section 81 , a driving section 82 , an imaging device 83 , and a signal processing section 84 .

The optical system configuration unit 81 includes an optical lens and the like, and causes an optical image of a subject to enter an imaging device 83 . The driving unit 82 controls the driving of the imaging device 83 by generating and outputting various timing signals related to the internal driving of the imaging device 83 . The signal processing unit 84 performs predetermined signal processing on the image signal output from the imaging element 83, and executes processing according to the result of the signal processing. In addition, the signal processing unit 84 outputs the image signal resulting from the signal processing to a subsequent stage, for example, recording it in a recording medium such as a memory, or transferring it to a predetermined server via a predetermined network.

Here, the sensitivity of the imaging device 80 can be improved by applying the solid-state imaging device in the above-described embodiment.

[Portable information terminal]
FIG. 20 is a diagram showing an appearance example of a portable information terminal 70 that is an application example of the embodiment of the present technology. In the figure, a indicates the front side of the mobile information terminal 70, and b indicates the back side of the mobile information terminal 70. As shown in FIG.

A display 71 is arranged at the center of the surface of the portable information terminal 70 to display various information. The display 71 also functions as a touch panel and receives input from the user.

A front camera 72 is arranged on the upper surface of the mobile information terminal 70 and is mainly used to capture an image of the user using the mobile information terminal 70 . On the other hand, a rear camera 73 is arranged on the upper part of the back surface of the portable information terminal 70 and is mainly used for capturing an image of a subject seen by the user.

Here, the sensitivity of the front camera 72 and the rear camera 73 can be improved by applying the solid-state imaging device in the above-described embodiment.

[application]
FIG. 21 is a diagram illustrating an example of a field to which an embodiment of the present technology is applied;

A solid-state imaging device according to an embodiment of the present technology can be used as a device that captures an image for viewing, such as a digital camera or a mobile device with a camera function.

In addition, this solid-state image pickup device is used for in-vehicle sensors that capture images of the surroundings and interior of a vehicle for safe driving such as automatic stopping and recognition of the driver's state, surveillance cameras that monitor running vehicles and roads, and inter-vehicle It can be used as a device used for transportation, such as a ranging sensor that performs ranging such as.

In addition, this solid-state imaging device can be used as a device for home electric appliances such as televisions, refrigerators, air conditioners, etc., in order to photograph user's gestures and perform device operations according to the gestures.

In addition, this solid-state imaging device can be used as a medical or health care device such as an endoscope or an angiography device that receives infrared light.

Further, this solid-state imaging device can be used as a security device such as a surveillance camera for crime prevention and a camera for person authentication.

Further, this solid-state imaging device can be used as a beauty device such as a skin measuring instrument for photographing the skin or a microscope for photographing the scalp.

Further, this solid-state imaging device can be used as a device for sports, such as an action camera or a wearable camera for sports.

Moreover, this solid-state imaging device can be used as an agricultural device such as a camera for monitoring the condition of a field or crops.

[Moving body]
The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure can be realized as a device mounted on any type of moving body such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, and robots. may

FIG. 22 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology according to the present disclosure can be applied.

Vehicle control system 12000 comprises a plurality of electronic control units connected via communication network 12001 . In the example shown in the figure, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an exterior information detection unit 12030, an interior information detection unit 12040, and an integrated control unit 12050. Also, as the functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio/image output unit 12052, and an in-vehicle network I/F (interface) 12053 are illustrated.

Drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the driving system control unit 12010 includes a driving force generator for generating driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism to adjust and a brake device to generate braking force of the vehicle.

Body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as headlamps, back lamps, brake lamps, winkers or fog lamps. In this case, body system control unit 12020 can receive radio waves transmitted from a portable device that substitutes for a key or signals from various switches. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, etc. of the vehicle.

External information detection unit 12030 detects information external to the vehicle in which vehicle control system 12000 is mounted. For example, the vehicle exterior information detection unit 12030 is connected with an imaging section 12031 . The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing such as people, vehicles, obstacles, signs, or characters on the road surface based on the received image.

The imaging unit 12031 is an optical sensor that receives light and outputs an electric signal according to the amount of received light. The imaging unit 12031 can output the electric signal as an image, and can also output it as distance measurement information. Also, the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.

The vehicle interior information detection unit 12040 detects vehicle interior information. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection section 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether the driver is dozing off.

The microcomputer 12051 calculates control target values for 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 12030 or the vehicle interior information detection unit 12040, and controls the drive system control unit. A control command can be output to 12010 . For example, the microcomputer 12051 realizes functions of ADAS (Advanced Driver Assistance System) including collision avoidance or shock mitigation of vehicles, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, etc. Cooperative control can be performed for the purpose of

In addition, the microcomputer 12051 controls the driving force generator, the steering mechanism, the braking device, etc. based on the information about the vehicle surroundings acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, so that the driver's Cooperative control can be performed for the purpose of autonomous driving, etc., in which vehicles autonomously travel without depending on operation.

Further, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the information detection unit 12030 outside the vehicle. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs cooperative control aimed at anti-glare such as switching from high beam to low beam. It can be carried out.

The audio/image output unit 12052 transmits at least one of audio and/or image output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle. In the example of FIG. 12, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are illustrated as output devices. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

FIG. 23 is a diagram showing an example of the installation position of the imaging unit 12031. As shown in FIG.

In the figure, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as an imaging unit 12031. FIG.

The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and windshield of the vehicle 12100, for example. An image pickup unit 12101 provided in the front nose and an image pickup unit 12105 provided above the windshield in the passenger compartment mainly acquire images in front of the vehicle 12100 . Imaging units 12102 and 12103 provided in the side mirrors mainly acquire side images of the vehicle 12100 . An imaging unit 12104 provided in the rear bumper or back door mainly acquires an image behind the vehicle 12100 . Forward images acquired by the imaging units 12101 and 12105 are mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

It should be noted that an example of the imaging range of the imaging units 12101 to 12104 is shown in FIG. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided in the front nose, the imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided in the side mirrors, respectively, and the imaging range 12114 The imaging range of an imaging unit 12104 provided in the rear bumper or back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and changes in this distance over time (relative velocity with respect to the vehicle 12100). , it is possible to extract, as the preceding vehicle, the closest three-dimensional object on the course of the vehicle 12100, which runs at a predetermined speed (for example, 0 km/h or more) in substantially the same direction as the vehicle 12100. can. Furthermore, the microcomputer 12051 can set the inter-vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including following stop control) and automatic acceleration control (including following start control). In this way, cooperative control can be performed for the purpose of automatic driving in which the vehicle runs autonomously without relying on the operation of the driver.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 converts three-dimensional object data related to three-dimensional objects to other three-dimensional objects such as motorcycles, ordinary vehicles, large vehicles, pedestrians, and utility poles. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into those that are visible to the driver of the vehicle 12100 and those that are difficult to see. Then, the microcomputer 12051 judges the collision risk indicating the degree of danger 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, an audio speaker 12061 and a display unit 12062 are displayed. By outputting an alarm to the driver via the drive system control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be performed.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not the pedestrian exists in the captured images of the imaging units 12101 to 12104 . Such recognition of a pedestrian is performed by, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and performing pattern matching processing on a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. This is done by a procedure that determines When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 outputs a rectangular outline for emphasis to the recognized pedestrian. is superimposed on the display unit 12062 . Also, the audio/image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 among the configurations described above. Specifically, by applying the technology according to the present disclosure to the imaging unit 12031, the sensitivity of the imaging unit 12031 can be improved.

[Endoscopic surgery system]
The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

FIG. 24 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system to which technology according to the present disclosure can be applied;

In the figure, an operator (physician) 11131 uses an endoscopic surgery system 11000 to perform surgery on a patient 11132 on a patient bed 11133 . As illustrated, an endoscopic surgery system 11000 includes an endoscope 11100, other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy treatment instrument 11112, and a support arm device 11120 for supporting the endoscope 11100. , and a cart 11200 loaded with various devices for endoscopic surgery.

An endoscope 11100 is composed of a lens barrel 11101 whose distal end is inserted into a body cavity of a patient 11132 and a camera head 11102 connected to the proximal end of the lens barrel 11101 . In the illustrated example, an endoscope 11100 configured as a so-called rigid scope having a rigid lens barrel 11101 is illustrated, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel. good.

The tip of the lens barrel 11101 is provided with an opening into which an objective lens is fitted. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel 11101 by a light guide extending inside the lens barrel 11101, where it reaches the objective. Through the lens, the light is irradiated toward the observation object inside the body cavity of the patient 11132 . Note that the endoscope 11100 may be a straight scope, a perspective scope, or a side scope.

An optical system and an imaging element are provided inside the camera head 11102, and reflected light (observation light) from an observation target is focused on the imaging element by the optical system. The imaging element photoelectrically converts the observation light to generate an electric signal corresponding to the observation light, that is, an image signal corresponding to the observation image. The image signal is transmitted to a camera control unit (CCU: Camera Control Unit) 11201 as RAW data.

The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and controls the operations of the endoscope 11100 and the display device 11202 in an integrated manner. Further, the CCU 11201 receives an image signal from the camera head 11102 and performs various image processing such as development processing (demosaicing) for displaying an image based on the image signal.

The display device 11202 displays an image based on an image signal subjected to image processing by the CCU 11201 under the control of the CCU 11201 .

The light source device 11203 is composed of, for example, a light source such as an LED (Light Emitting Diode), and supplies the endoscope 11100 with irradiation light for photographing a surgical site or the like.

Input device 11204 is an input interface for endoscopic surgery system 11000 . The user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204 . For example, the user inputs an instruction or the like to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) by the endoscope 11100 .

The treatment instrument control device 11205 controls driving of the energy treatment instrument 11112 for tissue cauterization, incision, blood vessel sealing, or the like. The pneumoperitoneum device 11206 inflates the body cavity of the patient 11132 for the purpose of securing the visual field of the endoscope 11100 and securing the operator's working space, and injects gas into the body cavity through the pneumoperitoneum tube 11111. send in. The recorder 11207 is a device capable of recording various types of information regarding surgery. The printer 11208 is a device capable of printing various types of information regarding surgery in various formats such as text, images, and graphs.

The light source device 11203 for supplying irradiation light to the endoscope 11100 for photographing the surgical site can be composed of, for example, a white light source composed of an LED, a laser light source, or a combination thereof. When a white light source is configured by a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high accuracy. It can be carried out. Further, in this case, the observation target is irradiated with laser light from each of the RGB laser light sources in a time division manner, and by controlling the drive of the imaging device of the camera head 11102 in synchronization with the irradiation timing, each of RGB can be handled. It is also possible to pick up images by time division. According to this method, a color image can be obtained without providing a color filter in the imaging element.

Further, the driving of the light source device 11203 may be controlled so as to change the intensity of the output light every predetermined time. By controlling the drive of the imaging device of the camera head 11102 in synchronism with the timing of the change in the intensity of the light to obtain an image in a time-division manner and synthesizing the images, a high dynamic A range of images can be generated.

Also, the light source device 11203 may be configured to be capable of supplying light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in body tissues, by irradiating light with a narrower band than the irradiation light (i.e., white light) during normal observation, the mucosal surface layer So-called Narrow Band Imaging, in which a predetermined tissue such as a blood vessel is imaged with high contrast, is performed. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained from fluorescence generated by irradiation with excitation light. In fluorescence observation, the body tissue is irradiated with excitation light and the fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and the body tissue is A fluorescence image can be obtained by irradiating excitation light corresponding to the fluorescence wavelength of the reagent. The light source device 11203 can be configured to be able to supply narrowband light and/or excitation light corresponding to such special light observation.

FIG. 25 is a block diagram showing an example of functional configurations of the camera head 11102 and CCU 11201 shown in FIG.

The camera head 11102 has a lens unit 11401 , an imaging section 11402 , a drive section 11403 , a communication section 11404 and a camera head control section 11405 . The CCU 11201 has a communication section 11411 , an image processing section 11412 and a control section 11413 . The camera head 11102 and the CCU 11201 are communicably connected to each other via a transmission cable 11400 .

A lens unit 11401 is an optical system provided at a connection portion with the lens barrel 11101 . Observation light captured from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401 . A lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

The imaging unit 11402 is composed of an imaging device. The imaging device constituting the imaging unit 11402 may be one (so-called single-plate type) or plural (so-called multi-plate type). When the image pickup unit 11402 is configured as a multi-plate type, for example, image signals corresponding to RGB may be generated by each image pickup element, and a color image may be obtained by synthesizing the image signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for respectively acquiring right-eye and left-eye image signals corresponding to 3D (Dimensional) display. The 3D display enables the operator 11131 to more accurately grasp the depth of the living tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multi-plate type, a plurality of systems of lens units 11401 may be provided corresponding to each imaging element.

Also, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102 . For example, the imaging unit 11402 may be provided inside the lens barrel 11101 immediately after the objective lens.

The drive unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405 . Thereby, the magnification and focus of the image captured by the imaging unit 11402 can be appropriately adjusted.

The communication unit 11404 is configured by a communication device for transmitting/receiving various information to/from the CCU 11201 . The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400 .

Also, the communication unit 11404 receives a control signal for controlling driving of the camera head 11102 from the CCU 11201 and supplies it to the camera head control unit 11405 . The control signal includes, for example, information to specify the frame rate of the captured image, information to specify the exposure value at the time of imaging, and/or information to specify the magnification and focus of the captured image. Contains information about conditions.

Note that the imaging conditions such as the frame rate, exposure value, magnification, and focus may be appropriately designated by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. good. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

A camera head control unit 11405 controls driving of the camera head 11102 based on the control signal from the CCU 11201 received via the communication unit 11404 .

The communication unit 11411 is configured by a communication device for transmitting/receiving various information to/from the camera head 11102 . The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400 .

The communication unit 11411 also transmits a control signal for controlling driving of the camera head 11102 to the camera head 11102 . Image signals and control signals can be transmitted by electrical communication, optical communication, or the like.

The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data transmitted from the camera head 11102 .

The control unit 11413 performs various controls related to the imaging of the surgical site and the like by the endoscope 11100 and the display of the captured image obtained by the imaging of the surgical site and the like. For example, the control unit 11413 generates control signals for controlling driving of the camera head 11102 .

In addition, the control unit 11413 causes the display device 11202 to display a picked-up image showing the surgical site and the like based on the image signal subjected to image processing by the image processing unit 11412 . At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 detects the shape, color, and the like of the edges of objects included in the captured image, thereby detecting surgical instruments such as forceps, specific body parts, bleeding, mist during use of the energy treatment instrument 11112, and the like. can recognize. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition result to display various types of surgical assistance information superimposed on the image of the surgical site. By superimposing and presenting the surgery support information to the operator 11131, the burden on the operator 11131 can be reduced and the operator 11131 can proceed with the surgery reliably.

A transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable compatible with electrical signal communication, an optical fiber compatible with optical communication, or a composite cable of these.

Here, in the illustrated example, wired communication is performed using the transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the endoscope 11100 and the imaging unit 11402 of the camera head 11102 among the configurations described above. Specifically, by applying the technology according to the present disclosure to the endoscope 11100 and the imaging unit 11402 of the camera head 11102, the sensitivity of the endoscope 11100 and the imaging unit 11402 of the camera head 11102 can be improved. can.

Although the endoscopic surgery system has been described as an example here, the technology according to the present disclosure may also be applied to, for example, a microsurgery system.

In addition, the above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the matters specifying the invention in the scope of claims have corresponding relationships. Similarly, the matters specifying the invention in the scope of claims and the matters in the embodiments of the present technology with the same names have corresponding relationships. However, the present technology is not limited to the embodiments, and can be embodied by various modifications to the embodiments without departing from the scope of the present technology.

It should be noted that the effects described in this specification are only examples and are not limited, and other effects may be provided.

Note that the present technology can also have the following configuration.
(1) a color filter provided for each two-dimensionally arranged pixel and corresponding to one of at least three different wavelength bands;
an antireflection layer provided on the light-receiving surface of the pixel that receives light incident through the color filter, and further comprising a periodic concavo-convex structure for some of the at least three types. Solid-state imaging device.
(2) The solid-state imaging device according to (1), wherein the color filter corresponds to any one of infrared, red, green, blue, ultraviolet, and achromatic color as the at least three different wavelength bands.
(3) the color filters are arranged according to a Bayer array;
The solid-state imaging device according to (1), wherein the antireflection layer has a flat film structure for pixels whose color filters are green filters, and has the periodic uneven structure for pixels whose color filters are blue filters. Device.
(4) The solid-state imaging device according to (3), wherein the antireflection layer has the periodic concave-convex structure even for pixels whose color filters are red filters.
(5) The solid-state imaging device according to any one of (1) to (4), wherein the periodic concave-convex structure is a structure in which inverted pyramid structures composed of silicon crystal planes (111) are periodically arranged.
(6) The solid-state imaging device according to (5), wherein the angle formed by the inverted pyramid structure with respect to the silicon substrate surface is a value arctan(2 ^1/2 ) of an arctangent function.
(7) The solid-state imaging device according to (5) or (6), wherein the distance between adjacent pyramids in the inverted pyramid structure is 200 nm to 800 nm.
(8) The solid-state imaging device according to any one of (5) to (7), wherein each side of the inverted pyramid structure has a length of 200 nm to 800 nm.
(9) The solid-state imaging device according to any one of (5) to (8), wherein the number of pyramids in the inverted pyramid structure is an integral number for each pixel.
(10) The antireflection layer includes a reflector made of a λ/4 wavelength plate for pixels whose color filters are green filters, and has the inverted pyramid structure for pixels whose color filters are ultraviolet or blue filters. The solid-state imaging device according to any one of (5) to (9), comprising a structure arranged periodically.
(11) The solid-state imaging device according to (10), wherein the antireflection layer has a structure in which the inverted pyramid structure is periodically arranged even for pixels whose color filters are red filters.
(12) a photoelectric conversion unit that converts the light received by each pixel into a voltage signal;
further comprising an element isolation unit that isolates the photoelectric conversion unit for each pixel,
The solid-state imaging device according to any one of (1) to (11), wherein the element isolation section has a structure in which a groove structure is carved into a silicon substrate.
(13) The solid-state imaging device according to (12), wherein the element isolation portion is formed by filling the groove structure with a metal material.
(14) The solid-state imaging device according to (13), wherein the metal material is mainly composed of tungsten, aluminum, copper, or metal alloys thereof.
(15) further comprising a phase difference detection pixel having one on-chip condensing structure in adjacent 2×1 pixels or 2×2 pixels;
The solid-state imaging device according to any one of (1) to (14), wherein the antireflection layer has a flat film structure for the phase difference detection pixels.
(16) a color filter provided for each two-dimensionally arranged pixel and corresponding to one of at least three different wavelength bands;
an antireflection layer provided on the light-receiving surface of the pixel that receives light incident through the color filter, and further comprising a periodic uneven structure for some of the at least three types;
a photoelectric conversion unit that converts the light received by each pixel into a voltage signal;
and a signal processing unit that performs predetermined signal processing on the voltage signal.

10 pixel region 11 pixel 12 transfer transistor 13 floating diffusion region 14 reset transistor 15 amplification transistor 16 selection transistor 17 photodiode 20 vertical drive circuit 30 horizontal drive circuit 40 control circuit 50 column signal processing circuit 60 output circuit 100 semiconductor substrate 111 to 114 reflection Prevention layer 120 Transfer gate 130 Floating diffusion region 140 Reset transistor 150 Amplification transistor 170 Photodiode 190 Element isolation part 191 Groove structure 200 Wiring layer 220 Wiring 310 On-chip lens 320 Color filter 330 Flattening film 340 Light shielding film 11100 Endoscope 11102 Camera Head 11402, 12031 Imaging unit

Claims (10)

In a semiconductor substrate having a plurality of photoelectric conversion units,
a plurality of units of first pixels each having a first color filter that transmits light in a red wavelength band;
a plurality of units of second pixels each having a second color filter that transmits light in a green wavelength band;
and a plurality of units of third pixels each having a third color filter that transmits light in a blue wavelength band, wherein the plurality of units of first pixels are provided with no concave portion on the light receiving surface of the semiconductor substrate,
A photodetector in which the plurality of units of third pixels has a concave portion on the light receiving surface of the semiconductor substrate. 2. The photodetector according to claim 1, wherein the plurality of units of the first pixels and the plurality of units of the second pixels are provided adjacent to each other. 3. The photodetector according to claim 2, wherein the plurality of units of the second pixels and the plurality of units of the third pixels are provided adjacent to each other. 2. The photodetector according to claim 1, further comprising an element isolation portion at a position that partitions the plurality of units of the first to third pixels. 5. The photodetector according to claim 4, wherein the plurality of units of the first pixels have a flat entire light-receiving surface of the semiconductor substrate surrounded by the element isolation portion. 5. The photodetector according to claim 4, wherein the element isolation portion is a groove structure formed in the semiconductor substrate. 5. The photodetector according to claim 4, wherein, in a cross-sectional view, the recesses of the plurality of units of third pixels are shallower than the element isolation portion. 7. The photodetector of claim 6 , wherein said trench structure is covered with an oxide film. 7. The photodetector according to claim 6 , wherein the groove structure is filled with a metal material. In a semiconductor substrate having a plurality of photoelectric conversion units,
a plurality of units of first pixels each having a first color filter that transmits light in a red wavelength band;
a plurality of units of second pixels each having a second color filter that transmits light in a green wavelength band;
and a plurality of units of third pixels each having a third color filter that transmits light in a blue wavelength band, wherein the plurality of units of first pixels are provided with no concave portion on the light receiving surface of the semiconductor substrate,
The electronic device, wherein the plurality of units of third pixels has a concave portion on the light receiving surface of the semiconductor substrate.

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