The present technology relates to a solid-state imaging apparatus designed to improve sensitivity while preventing worsening of color mixing. A substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on the upper side of the photoelectric conversion regions, a trench provided through the substrate and provided between the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on the light-receiving surface side of the substrate above the photoelectric conversion regions are included. The color filter over adjacent two of the photoelectric conversion regions is of the same color. The number of the recesses of the recessed region is larger at a high image height than at an image height center. The present technology can be applied to, for example, a back-illuminated solid-state imaging apparatus etc.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase of International Patent Application No. PCT/JP2020/014567 filed on Mar. 30, 2020, which claims priority benefit of Japanese Patent Application No. JP 2019-076307 filed in the Japan Patent Office on Apr. 12, 2019. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present technology relates to a solid-state imaging apparatus, and for example, relates to a solid-state imaging apparatus designed to improve sensitivity while preventing worsening of color mixing.

BACKGROUND ART

It has been proposed to provide, as a structure for preventing the reflection of incident light in a solid-state imaging apparatus, a minute recessed-and-protruded structure at an interface on the light-receiving surface side of a silicon layer in which photodiodes are formed (see, for example, Patent Documents 1 and 2).

CITATION LIST

Patent Documents

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the minute recessed-and-protruded structure, which can prevent the reflection of incident light to improve sensitivity, increases scattering and increases the amount of light leaking into adjacent pixels, and thus can worsen color mixing.

The present disclosure has been made in view of such circumstances, and is intended to improve sensitivity while preventing worsening of color mixing.

Solutions to Problems

A first solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, a trench provided through the substrate and provided between the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions, in which the color filter over adjacent two of the photoelectric conversion regions is of the same color.

A second solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, an on-chip lens provided on an upper side of the color filter, a trench provided through the substrate, the trench surrounding four of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions, in which the color filter over the four of the photoelectric conversion regions is of the same color, and the on-chip lens is provided over the four of the photoelectric conversion regions.

A third solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, an on-chip lens provided on an upper side of the color filter, a trench provided through the substrate, the trench surrounding adjacent two of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions, in which the color filter over the two of the photoelectric conversion regions is of the same color, and the on-chip lens is provided over the two of the photoelectric conversion regions.

A fourth solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, a trench provided through the substrate and provided between the photoelectric conversion regions, a metal film covering almost a half region of the photoelectric conversion regions on an upper side of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions.

A first solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, a trench provided through the substrate and provided between the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions. In addition, the color filter over adjacent two of the photoelectric conversion regions is of the same color.

A second solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, an on-chip lens provided on an upper side of the color filter, a trench provided through the substrate, the trench surrounding four of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions. In addition, the color filter over the four of the photoelectric conversion regions is of the same color, and the on-chip lens is provided over the four of the photoelectric conversion regions.

A third solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, an on-chip lens provided on an upper side of the color filter, a trench provided through the substrate, the trench surrounding adjacent two of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions. In addition, the color filter over the two of the photoelectric conversion regions is of the same color, and the on-chip lens is provided over the two of the photoelectric conversion regions.

A fourth solid-state imaging apparatus according to an aspect of the present technology includes a substrate, a plurality of photoelectric conversion regions provided in the substrate, a color filter provided on an upper side of the photoelectric conversion regions, a trench provided through the substrate and provided between the photoelectric conversion regions, a metal film covering almost a half region of the photoelectric conversion regions on an upper side of the photoelectric conversion regions, and a recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a mode for carrying out the present technology (hereinafter referred to as an embodiment) will be described.

<Schematic Configuration Example of Solid-State Imaging Apparatus>

FIG.1illustrates a schematic configuration of a solid-state imaging apparatus according to the present disclosure.

A solid-state imaging apparatus1inFIG.1includes a pixel array3with pixels2arranged in a two-dimensional array and peripheral circuitry around it in a semiconductor substrate12using, for example, silicon (Si) as a semiconductor. The peripheral circuitry includes a vertical drive circuit4, column signal processing circuits5, a horizontal drive circuit6, an output circuit7, a control circuit8, etc.

The pixels2each include a photodiode as a photoelectric conversion element and a plurality of pixel transistors. The plurality of pixel transistors includes, for example, four MOS transistors, a transfer transistor, a select transistor, a reset transistor, and an amplification transistor.

Alternatively, the pixels2may have a sharing pixel structure. This pixel sharing structure includes a plurality of photodiodes, a plurality of transfer transistors, a shared floating diffusion (floating diffusion region), and other individually shared pixel transistors. That is, in sharing pixels, photodiodes and transfer transistors constituting a plurality of unit pixels share other individual pixel transistors.

The control circuit8receives an input clock and data instructing an operation mode etc., and outputs data such as internal information of the solid-state imaging apparatus1. Specifically, on the basis of a vertical synchronization signal, a horizontal synchronization signal, and a master clock, the control circuit8generates a clock signal and a control signal on the basis of which the vertical drive circuit4, the column signal processing circuits5, the horizontal drive circuit6, etc. operate. Then, the control circuit8outputs the generated clock signal and control signal to the vertical drive circuit4, the column signal processing circuits5, the horizontal drive circuit6, etc.

The vertical drive circuit4is formed by, for example, a shift register, and selects a pixel drive wire10, provides a pulse for driving the pixels2to the selected pixel drive wire10, and drives the pixels2row by row. That is, the vertical drive circuit4selectively scans the pixels2of the pixel array3in the vertical direction sequentially row by row, and provides pixel signals based on signal charges generated in photoelectric conversion parts of the pixels2depending on the amount of received light, through vertical signal lines9to the column signal processing circuits5.

The column signal processing circuits5are disposed for the corresponding columns of the pixels2, and perform signal processing such as noise removal on signals output from the pixels2in one row for the corresponding pixel columns. For example, the column signal processing circuits5perform signal processing such as correlated double sampling (CDS) for removing fixed pattern noise peculiar to the pixels and AD conversion.

The horizontal drive circuit6is formed by, for example, a shift register, selects each of the column signal processing circuits5in order by sequentially outputting a horizontal scanning pulse, and causes each of the column signal processing circuits5to output a pixel signal to a horizontal signal line11.

The output circuit7performs signal processing on a signal successively provided from each of the column signal processing circuits5through the horizontal signal line11, for output.

For example, the output circuit7may perform only buffering, or may perform black level adjustment, column variation correction, various types of digital signal processing, etc. An input-output terminal13exchanges signals with the outside.

The solid-state imaging apparatus1formed as described above is a CMOS image sensor called a column AD system in which the column signal processing circuits5that perform CDS processing and AD conversion processing are disposed for the corresponding pixel columns.

Furthermore, the solid-state imaging apparatus1is a back-illuminated MOS solid-state imaging apparatus in which light enters from the back side opposite to the front side of the semiconductor substrate12on which the pixel transistors are formed.

First Embodiment

FIG.2is a diagram illustrating a cross-sectional configuration example of pixels2aaccording to a first embodiment.

The solid-state imaging apparatus1includes the semiconductor substrate12and a multilayer wiring layer and a support substrate (both not illustrated) formed on the front side thereof.

The semiconductor substrate12includes, for example, silicon (Si) and has a thickness of, for example, 1 to 6 μm. In the semiconductor substrate12, for example, an N-type (second conductivity type) semiconductor region42is formed in a P-type (first conductivity type) semiconductor region41in each pixel2a, to form a photodiode PD in each pixel. The P-type semiconductor region41provided in both the front and back surfaces of the semiconductor substrate12also serves as a hole and charge accumulation region for reducing dark current.

As illustrated inFIG.2, the solid-state imaging apparatus1includes an antireflection film61, a transparent insulating film46, color filter layers51, and on-chip lenses52stacked on the semiconductor substrate12in which the N-type semiconductor region42constituting the photodiode PD is formed in each pixel2a.

At an interface of the P-type semiconductor region41(light-receiving-surface-side interface) on the upper side of the N-type semiconductor regions42serving as charge accumulation regions, the antireflection film61is formed which prevents the reflection of incident light by recessed regions48formed with a fine recessed-and-protruded structure.

The antireflection film61has, for example, a laminated structure with a fixed charge film and an oxide film stacked in layers. For example, high-dielectric constant (high-k) insulating thin films produced by an atomic layer deposition (ALD) method may be used. Specifically, hafnium oxide (HfO2), aluminum oxide (Al2O3), titanium oxide (TiO2), strontium titanium oxide (STO), etc. may be used. In the example ofFIG.2, the antireflection film61includes a hafnium oxide film62, an aluminum oxide film63, and a silicon oxide film64stacked in layers.

Furthermore, a light-shielding film49is stacked on the antireflection film61to be formed between the pixels2a. As the light-shielding film49, a single-layer metal film of titanium (Ti), titanium nitride (TiN), tungsten (W), aluminum (Al), tungsten nitride (WN), or the like is used. Alternatively, a laminated film of these metals (for example, a laminated film of titanium and tungsten, a laminated film of titanium nitride and tungsten, or the like) may be used as the light-shielding film49.

The transparent insulating film46is formed on the entire back-side (light-incidence-plane-side) surface of the P-type semiconductor region41. The transparent insulating film46is of a material that transmits light and has insulation properties, and has a refractive index n1 smaller than the refractive index n2 of the semiconductor regions41and42(n1<n2). As the material of the transparent insulating film46, silicon oxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), hafnium oxide (HfO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), tantalum oxide (Ta2O5), titanium oxide (TiO2), lanthanum oxide (La2O3), praseodymium oxide (Pr2O3), cerium oxide (CeO2), neodymium oxide (Nd2O3), promethium oxide (Pm2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), gadolinium oxide (Gd2O3), terbium oxide (Tb2O3), dysprosium oxide (Dy2O3), holmium oxide (Ho2O3), thulium oxide (Tm2O3), ytterbium oxide (Yb2O3), lutetium oxide (Lu2O3), yttrium oxide (Y2O3), a resin, etc. may be used alone or in combination.

The color filter layers51are formed on the upper side of the transparent insulating film46including the light-shielding film49. A red, green, or blue color filter layer51is formed in each pixel. The color filter layers51are formed by spin-coating photosensitive resin containing coloring matter such as pigment or dye. Red, green, and blue colors are arranged on the basis of, for example, a Bayer array, but may be arranged by another arrangement method. In the example ofFIG.2, a green (G) color filter layer51is formed in the pixel2aon the right side, and a red (R) color filter layer51is formed in the pixel2aon the left side.

On the upper side of the color filter layers51, on-chip lenses52are formed for the corresponding pixels2a. The on-chip lenses52include, for example, a resin material such as a styrene resin, an acrylic resin, a styrene-acryl copolymer resin, or a siloxane resin. Incident light is concentrated by the on-chip lenses52. The concentrated light efficiently enters the photodiodes PD through the color filter layers51.

For the pixels2aillustrated inFIG.2, inter-pixel separation portions54that separate the pixels2afrom each other are formed in the semiconductor substrate12. Each inter-pixel separation portion54is formed by forming a trench through the semiconductor substrate12between the N-type semiconductor regions42constituting the photodiodes PD, forming the aluminum oxide film63on the inner surface of the trench, and further filling the trench with an insulator55when the silicon oxide film64is formed.

Note that a portion of the inter-pixel separation portion54filled with the silicon oxide film64may be filled with polysilicon.FIG.2illustrates a case where the silicon oxide film64is formed integrally with the insulator55.

By the formation of this inter-pixel separation portion54, the adjacent pixels2aare completely electrically separated from each other by the insulator55filling the trench. This can prevent charge generated inside the semiconductor substrate12from leaking to the adjacent pixels2a.

Furthermore, in the pixels2ain the first embodiment, a flat portion53is provided by providing a region of a predetermined width in which no recessed region48is formed between the pixels2aat the light-receiving-surface-side interface of the semiconductor substrate12. Each recessed region48is provided by forming a fine recessed structure. The structure is not formed in the region between the pixels2a, leaving a flat surface. Thus, the flat portion53is provided. This pixel structure provided with the flat portion53can reduce the occurrence of diffracted light in the region of the predetermined width (pixel separation region) in the vicinity of another adjacent pixel2a, to prevent the occurrence of color mixing.

Specifically, it is known that in a case where the recessed regions48are formed in the semiconductor substrate12, diffraction of vertical incident light occurs, and, for example, as the intervals (pitch) of recesses increase, diffracted light components increase, resulting in an increased proportion of light entering other adjacent pixels2.

Against this, in the solid-state imaging apparatus1, the flat portion53is provided in the region of the predetermined width between the pixels2awhere diffracted light is likely to leak to another adjacent pixel2a. At the flat portion53, the diffraction of vertical incident light does not occur, and thus the occurrence of color mixing can be prevented.

Each pixel2ain the pixel array3of the solid-state imaging apparatus1is configured as described above.

Here, the recessed regions48will be additionally described with reference toFIGS.3A,3B, and3C. The recessed regions48are each a region where fine recesses and protrusions are formed. The recesses and protrusions vary depending on where a plane used as a reference (hereinafter described as a reference plane) is set.

Furthermore, each recessed region48is a region having a fine recessed-and-protruded structure formed at the interface (light-receiving-surface-side interface) of the P-type semiconductor region41on the upper side of the N-type semiconductor region42serving as the charge accumulation region. The recessed-and-protruded structure is formed on the light-receiving-surface side of the semiconductor region42, in other words, the semiconductor substrate12. Thus, the reference plane can be a predetermined plane of the semiconductor substrate12. Here, the description will be continued with a case where a part of the semiconductor substrate12is set as the reference plane as an example.

The recessed region48illustrated inFIGS.3A,3B, and3Care formed in a triangular shape in a cross-sectional view. Since the recessed region48illustrated inFIGS.3A,3B, and3Care formed in the triangular shape in the cross-sectional view, as an example of the reference plane, a plane connecting the vertexes is set as the reference plane.

In the cross-sectional view, a plane including a line connecting, of the vertexes of the triangular shape of the recessed region48, the vertexes located on the transparent insulating film46side is set as a reference plane A. A plane including a line connecting, of the vertexes of the triangular shape of the recessed region48, the vertexes on the base side, in other words, the vertexes located on the semiconductor region42side is set as a reference plane C. A reference plane B is a plane located between the reference plane A and the reference plane C.

When the reference plane A is set as a reference, the shape of the recessed region48is a shape having triangular (valley-shaped) recesses facing downward with respect to the reference plane A. That is, when the reference plane A is set as a reference, valley regions are located below the reference plane A, and the valley regions correspond to the recesses. Thus, the recessed region48is a region where fine recesses are formed. In other words, when the reference plane A is set as a reference, the recessed region48can be said to be a region where a recess is formed between the vertex of a triangle and the vertex of an adjacent triangle, and fine recesses are formed.

When the reference plane C is set as a reference, the shape of the recessed region48is a shape having triangular (peak-shaped) protrusions facing upward with respect to the reference plane C. That is, when the reference plane C is set as a reference, regions forming peaks are located above the reference plane C, and the regions forming the peaks correspond to the protrusions. Thus, the recessed region48is a region where fine protrusions are formed. In other words, when the reference plane C is set as a reference, the recessed region48can be said to be a region where a protrusion is formed between the vertexes at the base of a triangular shape, and fine tops are formed.

When the reference plane B is set as a reference, the shape of the recessed region48is a shape having recesses and protrusions (valleys and peaks) with respect to the reference plane B. That is, in a case where the reference plane B is set as a reference, there are recesses forming valleys below the reference plane B, and protrusions forming peaks above, and thus it can be said to be a region including fine recesses and protrusions.

Thus, the recessed region48, whose shape is even a zigzag shape with peaks and valleys as illustrated inFIGS.3A,3B, and3C, can be defined as a region that can be expressed as a region formed with fine recesses, a region formed with fine protrusions, or a region formed with fine recesses and protrusions, depending on where the reference plane is set in the cross-sectional view of the pixel2.

Furthermore, in a case where the reference plane is set as, for example, an interface between the transparent insulating film46and the color filter layer51, the recessed region48illustrated inFIGS.3A,3B, and3Care of a shape having depressed regions (valleys), and thus the recessed region48can be said to be a region formed with fine recesses.

Furthermore, in a case where the reference plane is set as a boundary plane between the P-type semiconductor region41and the N-type semiconductor region42, the recessed region48is of a shape having protruding regions (peaks), and thus can be said to be a region formed with fine protrusions.

Thus, in the cross-sectional view of each pixel2, with a predetermined flat plane as the reference plane, the shape of the recessed region48can also be expressed, depending on whether it is formed in a valley shape or in a peak shape with respect to the reference plane.

Furthermore, in a case where the flat portion53is formed between the pixels2, the flat portion53is a region provided by providing the region of the predetermined width where no recessed region48is formed between the pixels2at the light-receiving-surface-side interface of the semiconductor substrate12. A plane including the flat portion53may be set as the reference plane.

Referring toFIG.2, in a case where the plane including the flat portion53is set as the reference plane, the recessed regions48can be said to have a shape having portions depressed below the reference plane, in other words, having valley-shaped portions, and thus can be said to be regions where fine recesses are formed.

Thus, each recessed region48is a region that can be expressed as a region formed with fine recesses, a region formed with fine protrusions, or a region formed with fine recesses and protrusions, depending on where the reference plane is set in the cross-sectional view of the pixel2.

In the following description, the description will be continued assuming that each recessed region48is a region formed with fine recesses, which is, as described above, an expression including a region such as a region formed with fine protrusions or a region formed with fine recesses and protrusions.

Second Embodiment

FIG.4is a diagram illustrating a cross-sectional configuration example of pixels2baccording to a second embodiment.

InFIG.4, the basic configuration of the solid-state imaging apparatus1is the same as the configuration illustrated inFIG.2. In the pixels2baccording to the second embodiment, inter-pixel separation portions54bthat completely separate the pixels2bfrom each other are formed in the semiconductor substrate12.

Each inter-pixel separation portion54bis formed by digging a trench through the semiconductor substrate12between the N-type semiconductor regions42constituting photodiodes PD, filling the trench with the insulator55(inFIG.4, the silicon oxide film64) on the inner surface of the trench, and further filling the inside of the insulator55with a light-shielding object56when the light-shielding film49is formed. The light-shielding object56is formed integrally with the light-shielding film49using metal having light-shielding properties.

By the formation of this inter-pixel separation portion54b, the adjacent pixels2bare electrically separated from each other by the insulator55filling the trench and optically separated from each other by the light-shielding object56. This can prevent charge generated inside the semiconductor substrate12from leaking to the adjacent pixel2b, and can prevent light from an oblique direction from leaking to the adjacent pixel2b.

Then, the pixels2baccording to the second embodiment also have a pixel structure in which the flat portion53is provided, to be able to reduce the occurrence of diffracted light in the pixel separation region to prevent the occurrence of color mixing.

Third Embodiment

FIG.5is a diagram illustrating a cross-sectional configuration example of pixels2caccording to a third embodiment.

InFIG.5, the basic configuration of the solid-state imaging apparatus1is the same as the configuration illustrated inFIG.2. In the pixels2caccording to the third embodiment, inter-pixel separation portions54cthat completely separate the pixels2cfrom each other are formed in the semiconductor substrate12.

At each inter-pixel separation portion54cbetween the pixels2caccording to the third embodiment, no light-shielding film49is provided at the flat portion53, which is a difference from the pixels2baccording to the second embodiment.

By the formation of this inter-pixel separation portion54c, the adjacent pixels2care electrically separated from each other by the insulator55filling the trench and optically separated from each other by the light-shielding object56. This can prevent charge generated inside the semiconductor substrate12from leaking to the adjacent pixel2c, and can prevent light from an oblique direction from leaking to the adjacent pixel2c.

Then, the pixels2caccording to the third embodiment also have a pixel structure in which the flat portion53is provided, to be able to reduce the occurrence of diffracted light in the pixel separation region to prevent the occurrence of color mixing.

<Effects of Providing Recessed Region>

Effects in the pixels2having the recessed regions48in the pixels2will be described with reference toFIGS.6A and6B.FIGS.6A and6Bare diagrams illustrating the effects of the pixel structure of the pixel2aillustrated inFIG.2.

FIG.6Ais a diagram illustrating the effects of the antireflection film61having the recessed region48. Since the antireflection film61has the recessed-and-protruded structure, the reflection of incident light is prevented. Consequently, the sensitivity of the solid-state imaging apparatus1can be improved.

FIG.6Bis a diagram illustrating the effects of the inter-pixel separation portions54of the trench structure. Without the provision of the inter-pixel separation portions54, there have been cases where incident light scattered by the antireflection film61passes through the photoelectric conversion region (semiconductor regions41and42). The inter-pixel separation portions54have the effect of reflecting incident light scattered by the antireflection film61to confine the incident light within the photoelectric conversion region. Consequently, the optical distance for silicon absorption can be extended, improving sensitivity.

Letting the refractive index of the inter-pixel separation portions54be n1=1.5 (corresponding to that of SiO2) and the refractive index of the semiconductor region41forming the photoelectric conversion region be n2=4.0, the refractive index difference (n1<n2) produces a waveguide effect (the photoelectric conversion region: a core, the inter-pixel separation portions54: a clad), and thus incident light is confined within the photoelectric conversion region. The recessed region48, which has a disadvantage of worsening color mixing by light scattering, can be combined with the inter-pixel separation portions54to cancel the worsening of color mixing, and further increases the angle of incidence traveling through the photoelectric conversion region, thereby creating an advantage of improving photoelectric conversion efficiency.

In addition, since the optical distance for silicon absorption can be extended, the structure can increase the optical path length, allowing even incident light with a long wavelength to be efficiently concentrated into the photodiode PD, and allowing improved sensitivity even to incident light with a long wavelength. The increased optical path length thus allows improved sensitivity even to infrared light (IR) with a long wavelength without increasing the thickness of the pixel2, in other words, the thickness of the semiconductor substrate12.

Fourth Embodiment

The pixels2ato2cin the first to third embodiments can be applied as pixels arranged in the pixel array3having a pixel arrangement as illustrated inFIG.7.

FIG.7is a diagram illustrating an example of a pixel arrangement of the pixel array3.FIG.7illustrates sixteen pixels of 4×4 in the pixel array3. In the array illustrated inFIG.7, color filters of three colors, red (R), green (G), and blue (B), are arranged in units of 2×2 pixels. One on-chip lens52is formed for each pixel.

In the array illustrated inFIG.7, the color filters of 4×4 pixels are set as a basic unit, in which a G filter of 2×2 pixels is placed at the upper left, a B filter of 2×2 pixels at the lower left, an R filter of 2×2 pixels at the upper right, and a G filter of 2×2 pixels at the lower right.

In the pixel array3, as illustrated inFIG.8, pixels are arranged in both a vertical direction and a horizontal direction with color filters of 4×4 pixels as a basic unit. InFIG.8, one quadrangle represents 2×2 pixels placed at a color filter of the same color.

Any of the pixels2ato2caccording to the first to third embodiments can be applied to all the pixels arranged in the pixel array3in which the pixels are arranged as above, to make them pixels in which the recessed regions48are formed. Here, a case where the pixels2ain the first embodiment are applied to pixels2din a fourth embodiment will be described as an example.

FIG.9is a cross-sectional view taken along line A-B in the pixel array3illustrated inFIG.8, andFIG.10is a cross-sectional view taken along line C-D.

As illustrated inFIG.9, in the cross-sectional view taken along line A-B, a color filter on the left side in the figure in the color filter layer51is red (R), and a color filter on the right side in the figure is green (G). Two pixels2dare placed at the red color filter. Likewise, two pixels2dare placed at the green color filter.

The configuration of the pixels2dillustrated inFIG.9has the same structure as that of the pixels2ain the first embodiment illustrated inFIG.2except that a color filter over two pixels is of the same color.

As illustrated inFIG.10, in the cross-sectional view taken along line C-D, a color filter on the left side in the figure in the color filter layer51is green (G), and a color filter on the right side in the figure is blue (B). Two pixels2dare placed at the green color filter. Likewise, two pixels2dare placed at the blue color filter.

The configuration of the pixels2dillustrated inFIG.10has the same structure as that of the pixels2ain the first embodiment illustrated inFIG.2except that a color filter over two pixels is of the same color.

As above, the pixels2dprovided with the recessed regions48can be applied to the configuration in which a color filter of the same color is placed at four pixels of 2×2. The arrangement of the pixels2dprovided with the recessed regions48in the pixel array3can improve sensitivity.

Fifth Embodiment

In the fourth embodiment, the case where the recessed region48is provided in each pixel arranged in the pixel array3has been described as an example. As a fifth embodiment, a case where the recessed regions48are provided to reduce the influence of vignetting will be described.

Reference is again made toFIGS.9and10. For example, as illustrated inFIG.9, a pixel adjacent to an R pixel is a G pixel. Furthermore, as illustrated inFIG.10, a pixel adjacent to a B pixel is a G pixel. Vignetting caused by a G pixel (vignetting caused by a green color filter (G filter)) can occur in an R pixel or a B pixel adjacent to the G pixel. Further, there is a sensitivity difference between a G pixel and an R pixel, and a G pixel generally tends to have a higher sensitivity than an R pixel. Likewise, there is a sensitivity difference between a G pixel and a B pixel, and a G pixel generally tends to have a higher sensitivity than a B pixel.

Furthermore, the influence of vignetting caused by a G filter is strong on the high image height side and weak in the central portion. That is, the influence of vignetting varies depending on the image height. In order to absorb such a difference in influence, the shape of the recessed regions48is varied depending on the image height. Specifically, the number of peaks or valleys of the recessed regions48is varied depending on the image height.

The provision of the recessed regions48can improve photoelectric conversion capability. The adjustment of the number of recesses and protrusions of the recessed regions48allows adjustment of sensitivity. Here, in a case where portions of each recessed region48located far from the color filter layer51are described as valley portions, sensitivity can be adjusted by the number of valley portions. It is considered that a large number of valley portions facilitate scattering, improving sensitivity. Thus, by varying the number of valleys of the recessed regions48, the difference in sensitivity depending on the image height is absorbed to reduce the influence of vignetting.

As illustrated inFIG.11, the pixel array3is divided into three regions. A region A is the image height center of the pixel array3. A region C is a high-image-height region of the pixel array3. A region B is a region between the region A and the region C and is a medium-image-height region.

FIG.12is a cross-sectional view of pixels2eplaced in the region A. As illustrated inFIG.12, no recessed regions48are formed in the pixels2eplaced in the region A.

FIG.13is a cross-sectional view of pixels2eplaced in the region B. As illustrated inFIG.13, of the pixels2eplaced in the region B, recessed regions48are formed in an R pixel and a B pixel placed on the adjacent sides of G pixels.

FIG.14is a cross-sectional view of pixels2eplaced in the region C. As illustrated inFIG.14, of the pixels2eplaced in the region B, recessed regions48are formed in an R pixel and a B pixel placed on the adjacent sides of G pixels.

Comparing the R pixels illustrated inFIGS.13and14, the number of valleys of the recessed region48in the R pixel placed in the region B illustrated inFIG.13is different from the number of valleys of the recessed region48in the R pixel placed in the region C illustrated inFIG.14. The number of the valleys of the recessed region48in the R pixel placed in the region B illustrated inFIG.13is two. The number of the valleys of the recessed region48in the R pixel placed in the region C illustrated inFIG.14is five.

Comparing the B pixels illustrated inFIGS.13and14, the number of valleys of the recessed region48in the B pixel placed in the region B illustrated inFIG.13is different from the number of valleys of the recessed region48in the B pixel placed in the region C illustrated inFIG.14. The number of the valleys of the recessed region48in the B pixel placed in the region B illustrated inFIG.13is two. The number of the valleys of the recessed region48in the B pixel placed in the region C illustrated inFIG.14is five.

In general, sensitivity tends to decrease with increasing image height. Therefore, to increase the sensitivity of pixels2eplaced at the high image height where sensitivity becomes lower, the number of valleys of the recessed regions48is made larger than that of pixels located at places other than those at the high image height.

Here, the pixel array3is divided into the three regions, the region where no recessed regions48are formed, the region where the number of valleys of the recessed regions48is small, and the region where the number of valleys of the recessed regions48is large. The number of valleys of the recessed regions48may be discrete like this or may be continuous. In a case where the number of valleys of the recessed regions48is set continuously, it is gradually increased with increasing image height.

Such adjustment of the number of valleys of the recessed regions48allows adjustment in sensitivity. Thus, the sensitivity of the pixels arranged in the pixel array3can be adjusted uniformly by adjusting the shape of the recessed regions48.

Sixth Embodiment

The pixels2ato2cin the first to third embodiments can also be applied to the pixel array3having a pixel arrangement as illustrated inFIG.15.

FIG.15is a diagram illustrating an example of a pixel arrangement of the pixel array3.FIG.15illustrates sixteen pixels of 4×4 in the pixel array3. In the pixel arrangement illustrated inFIG.15, as in the pixel arrangement illustrated inFIG.7, color filters of three colors, red (R), green (G), and blue (B), are arranged in units of 2×2 pixels. In the pixel arrangement illustrated inFIG.15, unlike in the pixel arrangement illustrated inFIG.7, one on-chip lens52is formed for four pixels of 2×2 pixels.

In the array illustrated inFIG.15, the color filters of 4×4 pixels are set as a basic unit, in which a G filter of 2×2 pixels is placed at the upper left, a B filter of 2×2 pixels at the lower left, an R filter of 2×2 pixels at the upper right, and a G filter of 2×2 pixels at the lower right. Each on-chip lens52is formed for four pixels of 2×2 in the basic unit.

In the pixel array3, pixels are arranged in both a vertical direction and a horizontal direction with color filters of 4×4 pixels as a basic unit. Any of the pixels2ato2caccording to the first to third embodiments can be applied to all the pixels arranged in the pixel array3in which the pixels are arranged as above, to make them pixels in which the recessed regions48are formed. Alternatively, any of the pixels2ato2cin the first to third embodiments can be applied to some pixels, depending on the image height and the colors of the color filters.

Here, a sensitivity difference that can occur in a case where one on-chip lens52is provided for four pixels of the same color as inFIG.15, and no recessed region48is formed will be described with reference toFIGS.16A and16B.

In the following description, the photoelectric conversion region including the P-type semiconductor region41and the N-type semiconductor region42will be described as a photodiode (PD)42, and the reference numeral given in the figure is shown to indicate the portion of the semiconductor region42to continue description.

FIG.16Ais a cross-sectional view of pixels placed near the center of the pixel array3(at the image height center).FIG.16Bis a cross-sectional view of pixels placed near an edge of the pixel array3(at the high image height). Furthermore, the pixels illustrated inFIGS.16A and16Bcorrespond to pixels of a conventional configuration in which one on-chip lens52is provided for four pixels of the same color.

Referring toFIG.16A, for example, a PD42-1and a PD42-2are placed under a G filter illustrated on the left side in the figure. One on-chip lens52is formed over the PD42-1and the PD42-2. No inter-pixel separation portion54is formed between the PD42-1and the PD42-2. Furthermore, no light-shielding film49is formed between the PD42-1and the PD42-2.

An inter-pixel separation portion54is formed in a portion corresponding to a space between the G filter and the B filter, but has a configuration in which, instead of a penetrating trench, a non-penetrating trench is filled with the hafnium oxide film62and the silicon oxide film64.

Thus, no inter-pixel separation portion54and no light-shielding film49are formed within four pixels of 2×2 at which a color filter of the same color is placed. This configuration prevents a reduction in the sensitivity of the four pixels.

The pixels2placed on the high image height side basically have a configuration similar to that of the pixels2placed at the image height center, but are formed, for pupil correction, such that the on-chip lenses52and the color filter layers51are located closer to the image height center. Referring toFIG.16B, the on-chip lenses52, the color filter layers51, and the light-shielding film49are placed at positions shifted to the left in the figure.

Pupil correction is performed on the pixels2placed on the high image height side so that light equally enters the PD42-1and the PD42-2. However, the amount of pupil correction for this pupil correction is set to, for example, an amount to allow light to equally enter the PD42-1and the PD42-2in the G pixels. In a case where the amount of pupil correction optimal for the G pixels is set, it may not be optimal for the R pixels and the B pixels in terms of chromatic aberration.

Taking the G pixel and the B pixel illustrated inFIG.16Bas an example, light equally enters the PD42-1and the PD42-2placed under the G filter. On the other hand, light does not equally enter the PD42-1and the PD42-2placed under the B filter. In the conditions illustrated inFIG.16B, more light enters the PD42-1than the PD42-2. In other words, the sensitivity of the PD42-1can be different from the sensitivity of the PD42-2.

Furthermore, as described in the fifth embodiment, there is a sensitivity difference between the G pixels and the B pixels. Likewise, there is a sensitivity difference between the G pixels and the R pixels. In order to absorb such a sensitivity difference, the recessed regions48can be provided in pixels having a lower sensitivity.

FIG.17illustrates a cross-sectional configuration example of pixels2fin a sixth embodiment. LikeFIG.16B,FIG.17illustrates a G pixel and a B pixel placed on the high image height side. An inter-pixel separation portion54between the pixels2fillustrated inFIG.17has a configuration in which a penetrating trench is filled with the hafnium oxide film62and the silicon oxide film64.

The formation of the inter-pixel separation portions54penetrating like this can prevent leakage of light between pixels at which filters of different colors are placed, to reduce color mixing. Furthermore, the inter-pixel separation portions54reflect light, providing the effect of confining the light within the pixels2fs

Of the G pixel and the B pixel illustrated inFIG.17, no recessed region48fis formed in the G pixel, but a recessed region48fis formed in the B pixel. As described above, when the G pixel and the B pixel are compared, the sensitivity of the B pixel is more likely to decrease than that of the G pixel. Thus, the recessed region48fis formed in the B pixel to improve the sensitivity of the B pixel.

FIG.18illustrates a G pixel and an R pixel placed on the high image height side. Of the G pixel and the R pixel illustrated inFIG.18, no recessed region48fis formed in the G pixel, but a recessed region48fis formed in the R pixel. As described above, when the G pixel and the R pixel are compared, the sensitivity of the R pixel is more likely to decrease than that of the G pixel. Thus, the recessed region48fis formed in the R pixel to improve the sensitivity of the R pixel.

As illustrated inFIGS.17and18, no recessed region48fis formed in the G pixel, and the recessed region48fis formed in the B pixel or/and the R pixel. The recessed region48fmay be formed in both the B pixel and the R pixel placed at the high image height, or may be formed in only one of the B pixel and the R pixel.

Furthermore, in a case where the recessed region48fis formed in the B pixel or/and the R pixel, the shape of the recessed region48fmay be optimized for each wavelength of incident light to adjust sensitivity uniformly. An example is shown inFIGS.19A and19B.

Comparing a B pixel illustrated inFIG.19Aand an R pixel illustrated inFIG.19B, the number of valleys of a recessed region48in the B pixel illustrated inFIG.19Ais different from the number of valleys of a recessed region48in the R pixel illustrated inFIG.19B. The number of the valleys of the recessed region48in the B pixel illustrated inFIG.19Ais five. The number of the valleys of the recessed region48in the R pixel illustrated inFIG.19Bis ten.

In this case, when the B pixel and the R pixel are compared, the sensitivity of the R pixel tends to be lower than that of the B pixel. Thus, the number of the valleys of the recessed region48in the R pixel is made larger than the number of the valleys of the recessed region48in the B pixel.

Further, the shape of the recessed regions48fmay be varied (the number of valleys may be varied) depending on the image height. As described with reference toFIG.11, the pixel array3is divided into the three regions. The region A is the image height center of the pixel array3. The region B is the middle-image-height region of the pixel array3. The region C is the high-image-height region of the pixel array3.

FIG.20is a cross-sectional view of pixels2fplaced in the region A. As illustrated inFIG.20, no recessed regions48fare formed in the pixels2fplaced in the region A.

FIG.21is a cross-sectional view of pixels2fplaced in the region B. As illustrated inFIG.21, a recessed region48fis formed in a B pixel of the pixels2fplaced in the region B.

FIG.22is a cross-sectional view of pixels2fplaced in the region C. As illustrated inFIG.21, a recessed region48fis formed in a B pixel of the pixels2fplaced in the region C.

Comparing the B pixels illustrated inFIGS.21and22, the number of valleys of the recessed region48fin the B pixel placed in the region B illustrated inFIG.21is different from the number of valleys of the recessed region48fin the B pixel placed in the region C illustrated inFIG.22. The number of the valleys of the recessed region48fin the B pixel placed in the region B illustrated inFIG.21is five. The number of the valleys of the recessed region48in the B pixel placed in the region C illustrated inFIG.22is ten.

In general, sensitivity tends to decrease with increasing image height. Therefore, to increase the sensitivity of pixels2fplaced on the high-image-height side where sensitivity becomes lower, the number of valleys of the recessed regions48is made larger than that of pixels located at places other than those at the high image height.

Although R pixels are not illustrated, recessed regions48fare formed in R pixels placed at the middle image height and the high image height. Furthermore, the number of valleys of the recessed region48fin the R pixel placed at the high image height is made larger than the number of valleys of the recessed region48fin the R pixel placed at the medium image height.

Here, the pixel array3is divided into the three regions, the region where no recessed regions48fare formed, the region where the number of valleys of the recessed regions48fis small, and the region where the number of valleys of the recessed regions48fis large. The number of valleys of the recessed regions48fmay be discrete like this or may be continuous. In a case where the number of valleys of the recessed regions48fis set continuously, it is gradually increased with increasing image height.

Such adjustment of the number of valleys of the recessed regions48fallows adjustment in sensitivity. Thus, the sensitivity of the pixels arranged in the pixel array3can be adjusted uniformly by adjusting the shape of the recessed regions48f.

Further, a configuration in which the shape of the recessed regions48fvaries (the number of valleys varies) depending on the image height will be additionally described.

As described with reference toFIGS.16A and16B, at a higher image height, a sensitivity difference can occur even among four pixels (four PDs42) of the same color. Referring again toFIG.16B, in the B pixel, the PD42-1and the PD42-2placed under the B filter can cause a sensitivity difference and can be nonuniform in sensitivity.

Therefore, of the four PDs42of the same color, a recessed region48fis formed over a PD42whose sensitivity tends to be lower, so as to reduce the sensitivity difference among the four PDs42of the same color.

In the region A (at the image height center), there is not much sensitivity difference, and thus the pixels2fin which no recessed regions48fare formed are placed as illustrated inFIG.20.

FIG.23is a cross-sectional view of pixels2fplaced in the region B (at the medium image height). As illustrated inFIG.23, a recessed region48fis formed in a B pixel of the pixels2fplaced in the region B. Furthermore, in order to absorb a sensitivity difference within the B pixel, the recessed region48fis formed on the PD42-1side, and no recessed region48fis formed on the PD42-2side.

FIG.24is a cross-sectional view of pixels2fplaced in the region C (at the high image height). As illustrated inFIG.24, a recessed region48fis formed in a B pixel of the pixels2fplaced in the region C. Furthermore, in order to absorb a sensitivity difference within the B pixel, the recessed region48fis formed on the PD42-1side, and no recessed region48fis formed on the PD42-2side.

In this case, the B pixel is placed at a position where the PD42-1becomes lower in sensitivity than the PD42-2. Thus, the recessed region48fis formed at the PC42-1, on the PD42-1side, and no recessed region48fis formed on the PD42-2side. As described with reference toFIG.15, the B pixel includes four PDs42sharing a B filter. Of the four PDs42, a recessed region48fis formed over one, two, or three PDs42having a lower sensitivity than the other PD(s)42.

Comparing the B pixels illustrated inFIGS.23and24, the number of valleys of the recessed region48fin the B pixel placed in the region B illustrated inFIG.23is different from the number of valleys of the recessed region48fin the B pixel placed in the region C illustrated inFIG.24. The number of the valleys of the recessed region48fin the B pixel placed in the region B illustrated inFIG.23is three. The number of the valleys of the recessed region48in the B pixel placed in the region C illustrated inFIG.22is five.

As in the case described above, sensitivity tends to decrease with increasing image height. Therefore, to increase the sensitivity of pixels2fplaced at the high image height where sensitivity becomes lower, the number of valleys of the recessed regions48is made larger than that of pixels located at places other than those at the high image height.

Although R pixels are not illustrated, recessed regions48fare formed in R pixels placed at the middle image height and the high image height. Furthermore, of four PDs42included in each R pixel, a recessed region48fis formed over one, two, or three PDs42on the side where sensitivity is considered to be lower. Furthermore, the number of valleys of the recessed region48fin the R pixel placed at the high image height is made larger than the number of valleys of the recessed region48fin the R pixel placed at the medium image height.

Here, the pixel array3is divided into the three regions, the region where no recessed regions48fare formed, the region where the number of valleys of the recessed regions48fis small, and the region where the number of valleys of the recessed regions48fis large. The number of valleys of the recessed regions48fmay be discrete like this or may be continuous. In a case where the number of valleys of the recessed regions48fis set continuously, it is gradually increased with increasing image height.

Note that the sixth embodiment has described, as an example, the case where the amount of pupil correction appropriate for the G pixels is set, and thus has described the recessed regions48fformed in the B pixels and the R pixels. In a case where the amount of pupil correction appropriate for the B pixels is set, recessed regions48fare formed in the G pixels and the R pixels. Furthermore, in a case where the amount of pupil correction appropriate for the R pixels is set, recessed regions48fare formed in the G pixels and the B pixels.

Thus, by providing a recessed region48fin a pixel2fhaving a structure in which a color filter of the same color and one on-chip lens52are shared by four pixels (four PDs42), light can also be more efficiently collected in the PDs42, and photoelectric conversion efficiency can be improved. Further, by adjusting the shape (the number of valleys) of the recessed regions48faccording to the color and the image height, sensitivity can be made uniform

Seventh Embodiment

The pixels2ato2cin the first to third embodiments can also be applied to pixels that detect a phase difference. A phase difference is detected, for example, to perform autofocus (AF).

FIGS.25A and25Bare cross-sectional views of pixels that detect a phase difference, in which one pixel is divided into two PDs, and light is received by each PD. The pixels illustrated inFIGS.25A and25Bhave a pixel structure to which the present technology is not applied.

FIGS.25A and25Bare pixels2having the same structure. In each pixel2, under one on-chip lens52, a color filter of one color, a G filter inFIGS.25A and25B, is placed, and two PDs42-1and42-2are placed. An intra-pixel separation portion101is formed between the PD42-1and the PD42-2.

When a pixel surrounded by inter-pixel separation portions54is considered as one pixel, one pixel includes two PDs42-1and42-2. The intra-pixel separation portion101is formed between the PD42-1and the PD42-2. The intra-pixel separation portion101is formed by forming a P-type or N-type region by ion implantation, for example. Whether the intra-pixel separation portion101is a P-type region or an N-type region is determined by the configuration of the PDs42.

Referring toFIG.25A, light from the right direction with respect to the pixel2is received by the PD42-2placed on the right side in the pixel2. Referring toFIG.25B, light from the left direction with respect to the pixel2is received by the PD42-1placed on the left side in the pixel2. Thus, by separating the inside of the pixel and providing the PD42-1and the PD42-2, light coming from a left part and light coming from a right part can be separately received.

The PD42-1and the PD42-2separately receive light coming from a left part and light coming from a right part, so that a focus position can be detected as illustrated inFIG.26.

Specifically, in rear focus or in front focus, an output from the PD42-1and an output from the PD42-2do not match (outputs of paired phase difference pixels do not match). When focus is achieved, an output from the PD42-1and an output from the PD42-2match (outputs of the paired phase difference pixels match). When rear focus or front focus is determined, a lens group (not illustrated) is moved to a position to achieve focus, allowing the detection of a focal point.

In a case where a focus position is detected by such a phase difference method, a focal position can be detected at a relatively high speed, allowing high-speed autofocus. However, since one pixel is divided into two PDs42, a decrease in sensitivity can be involved. For example, there may be cases where it is difficult to detect a focal position in a dark place or the like.

Since the formation of recessed regions48can improve sensitivity, by forming recessed regions48in pixels for detecting a phase difference as illustrated inFIGS.25A and25B, decreased sensitivity is complemented and further improved.

FIG.27is a diagram illustrating a cross-sectional configuration of pixels2gin a seventh embodiment.FIG.27illustrates a G pixel on the left side and a B pixel on the right side. In each pixel2g, two PDs42are formed under one on-chip lens52, and an intra-pixel separation portion101is formed between the two PDs42.

Furthermore, inter-pixel separation portions54are formed to surround a region including the two PDs42and the intra-pixel separation portion101. In addition, a recessed region48is formed over the region including the two PDs42and the intra-pixel separation portion101.

As in the first to sixth embodiments, the formation of the recessed region48can improve the sensitivity of the PDs42. Furthermore, as in the first to sixth embodiments, the formation of the inter-pixel separation portions54can prevent light from leaking to the adjacent pixels2gto reduce color mixing. Moreover, the inter-pixel separation portions54reflect light, providing the effect of confining the light within the pixel2g.

By the provision of the recessed region48, incident light is scattered. For example, light incident on the PD42-1is scattered and can enter the PD42-2, decreasing the degree of separation. Therefore, as illustrated inFIG.28, the recessed region48may not be formed on the intra-pixel separation portion101to make it flat.

A recessed region48g′ formed in a pixel g′ illustrated inFIG.28is not formed on the intra-pixel separation portion101but is formed in a flat shape. In other words, the recessed region48g′ is formed in open regions of the PDs42, and is not formed in regions other than the open regions.

In this manner, the recessed region48g′ may be formed in the open regions of the PDs42. The degree of separation of the pixel2g′ in which the recessed region48g′ is formed only in the open regions of the PDs42like this is higher than the degree of separation of the pixel2gillustrated inFIG.27.

In order to further enhance the degree of separation, a configuration as illustrated inFIG.29may be employed. In a pixel2g″ illustrated inFIG.29, the silicon oxide film64, which is one of the films constituting a recessed region48g, is formed in the intra-pixel separation portion101to enhance the degree of separation.

A G pixel and a B pixel are illustrated inFIG.29. The G pixel has a configuration similar to that of the pixel2g′ illustrated inFIG.28. The B pixel includes a silicon oxide film64g″ formed in the intra-pixel separation portion101. The silicon oxide film64also fills the inter-pixel separation portions54. The inter-pixel separation portions54are provided to prevent light from leaking into adjacent pixels2g.

Thus, by forming the silicon oxide film64g″ in the intra-pixel separation portion101, leakage of light can be prevented between the PD42-1and the PD42-2placed in the B pixel. Since leakage of light can be prevented between the PD42-1and the PD42-2, the degree of separation can be increased.

FIG.29illustrates an example in which the silicon oxide film64g″ is formed in the intra-pixel separation portion101in the B pixel, and no silicon oxide film64g″ is formed in the intra-pixel separation portion101in the G pixel. The silicon oxide film64g″ may be formed in pixels corresponding to a color that tends to decrease the degree of separation. In the example illustrated inFIG.29, since the B pixel tends to be lower in the degree of separation, the silicon oxide film64g″ is formed in the intra-pixel separation portion101. Since the G pixel does not tend to be lower in the degree of separation than the B pixel, no silicon oxide film64g″ is formed in the intra-pixel separation portion101in the illustrated example.

Furthermore,FIG.29illustrates an example in which the silicon oxide film64g″ is formed to the middle of the intra-pixel separation portion101. However, it may be formed to the wiring layer side like the silicon oxide film64gin the inter-pixel separation portions54. The degree of separation can be adjusted by the depth of the silicon oxide film64g″ to the middle of the intra-pixel separation portion101. Specifically, by forming the silicon oxide film64g″ deeper to the middle of the intra-pixel separation portion101, leakage of light into the adjacent PD42can be prevented more to enhance the degree of separation.

Whether or not to form the silicon oxide film64g″ to the middle of the intra-pixel separation portion101and how far are set, for example, to ensure a desired degree of separation or more. For example, to ensure a degree of separation of 1.6 or more, the silicon oxide film64g″ is formed in the intra-pixel separation portion101in a pixel in which the degree of separation is not 1.6 or more. Furthermore, in formation, the depth to which the silicon oxide film64g″ is formed in the intra-pixel separation portion101is set to ensure a degree of separation of 1.6 or more.

In this manner, the silicon oxide film64g″ may be formed to ensure a desired degree of separation, or the silicon oxide film64g″ may be formed in the intra-pixel separation portion101in each of the G pixels, B pixels, and R pixels including an R pixel not illustrated.

Further, the shape of the recessed regions48may be varied depending on the image height. Here, the description will be continued with the pixels2gillustrated inFIG.27in which the recessed region48gis formed in each pixel as an example.

FIG.30is a cross-sectional view of pixels2gplaced on the high image height side. In a case where pixels2gplaced at the image height center are the pixels2gillustrated inFIG.27, pixels2gplaced at the high image height may be the pixels2gillustrated inFIG.30.

Comparing the pixels2gillustrated inFIGS.27and30, the number of valleys of the recessed regions48gin the pixels2gplaced at the image height center illustrated inFIG.27is different from the number of valleys of the recessed regions48gin the pixels2gplaced at the high image height illustrated inFIG.30. The number of valleys of the recessed region48gformed above one PD42in each pixel2gplaced at the image height center illustrated inFIG.27is five, and the number of valleys of the recessed region48formed above one PD42in each pixel2gplaced at the high image height illustrated inFIG.30is three.

In a configuration in which two PDs42are provided in one pixel2g, color mixing between the PDs42in the pixel tends to be greater on the high image height side than at the image height center. Increasing the number of valleys of the recessed regions48gallows light to be scattered more, improving the sensitivity of the PDs42. However, light scattering can increase color mixing.

As described above, the number of valleys of the recessed regions48gin the pixels2gplaced on the high image height side may be made smaller than the number of valleys of the recessed regions48gin the pixels2gplaced at the image height center, to prevent color mixing from increasing on the high image height side.

Although R pixels are not illustrated, the number of valleys of a recessed region48gin an R pixel placed at the high image height is made smaller than the number of valleys of a recessed region48gin an R pixel placed at the image height center.

Here, the pixel array3is divided into two regions, a region where the number of valleys of the recessed regions48gis small, and a region where the number of valleys of the recessed regions48gis large. The number of valleys of the recessed regions48gmay be discrete like this or may be continuous. In a case where the number of valleys of the recessed regions48gis set continuously, it is gradually decreased with increasing image height.

Such adjustment of the number of valleys of the recessed regions48fcan prevent color mixing.

Furthermore, as illustrated inFIG.31, a structure in which the size of recesses of recessed regions48is changed to prevent color mixing may be used.FIG.31is a diagram illustrating another configuration of the pixels2gplaced on the high image height side.

The recessed regions48gin the pixels2gillustrated inFIG.31are compared with the recessed regions48gin the pixels2gillustrated inFIG.27. Comparing the inclination of a side of one recess (valley) of the recessed regions48gin the pixels2g, the inclination of the side of the recess of the recessed regions48gin the pixels2gillustrated inFIG.31is made gentler than the inclination of the side of the recess of the recessed regions48gin the pixels2gillustrated inFIG.27.

In other words, the recesses of the recessed regions48gin the pixels2gillustrated inFIG.31are made larger than the recesses of the recessed regions48gin the pixels2gillustrated inFIG.27. By adjusting the size of the recesses, the degree of scattering of light can be reduced or increased. By adjusting the degree of scattering of light, color mixing can be prevented.

Such adjustment of the size of valleys of the recessed regions48fcan prevent color mixing.

On the high image height side, a sensitivity difference can occur between the two PDs42formed in one pixel2g. The shape of the recessed regions48gmay be varied within one pixel. For example, as illustrated inFIG.32, the number of valleys of a recessed region48gformed above a PD42-1in each pixel2gis made different from the number of valleys of a recessed region48gformed above a PD42-2. The number of the valleys of the recessed region48gformed above the PD42-1in each pixel2gis three, and the number of the valleys of the recessed region48gformed above the PD42-2in each pixel2gis five.

Comparing the PD42-1and the PD42-2illustrated inFIG.32, in a case where the sensitivity of the PD42-2is more likely to decrease than that of the PD42-1, the number of the valleys of the recessed region48gabove the PD42-2is made larger than the number of the valleys of the recessed region48gabove the PD42-1. By forming the recesses like this, even in a case where the sensitivity of the PD42-2becomes lower than the sensitivity of the PD42-1, the sensitivity of the PD42-2can be improved to make the sensitivity of the PD42-1and the sensitivity of the PD42-2match.

Thus, by adjusting the numbers of recesses of recessed regions48in one pixel, adjustment may be made to prevent the occurrence of a sensitivity difference between PDs42formed in one pixel. Furthermore, here, the case of adjusting the numbers of recesses has been described as an example, but, as described with reference toFIG.31, the sizes of recesses may be adjusted to prevent the occurrence of a sensitivity difference between PDs42.

Thus, by providing the recessed regions48in pixels each having two PDs therein, light can also be more efficiently collected in the PDs42, and photoelectric conversion efficiency can be improved. Further, by adjusting the shape (the number of valleys) of recessed regions48depending on the color and/or the image height, sensitivity can be made uniform, and color mixing can be reduced.

Eighth Embodiment

The pixels2ato2cin the first to third embodiments can also be applied to pixels that detect a phase difference. A phase difference is detected, for example, to perform autofocus (AF).

With reference toFIGS.33and34, a pixel for detecting a phase difference in which one on-chip lens is placed for two pixels will be described.FIG.33is a perspective schematic diagram illustrating a range of sixteen (=4×4) pixels extracted in a solid-state imaging device, of which two pixels constitute a pixel2hbfor phase difference detection, and the other fourteen pixels are normal pixels2ha.

FIG.34is a cross-sectional view of pixels2htaken along line A-A′ illustrated inFIG.33.FIG.34illustrates normal pixels2haand the pixel2hbfor phase difference detection to which the present technology is not applied.

Of the pixels2h, a pixel2hfor detecting a phase difference is described as a pixel2hb, and pixels other than the pixel2hb(normal pixels) are described as pixels2ha. The normal pixels2hamay be, for example, pixels having a configuration equivalent to that of the pixels2ato2cin the first to third embodiments.

In the pixel2hbfor phase difference detection, under one on-chip lens52b, a color filter of one color, a G filter inFIG.34, is placed, and two PDs42-1and42-2are placed. The intra-pixel separation portion101is formed between the PD42-1and the PD42-2.

When a pixel located between inter-pixel separation portions54is defined as one pixel, one pixel is divided into two PDs42-1and42-2. The intra-pixel separation portion101is formed between the PD42-1and the PD42-2. The intra-pixel separation portion101is formed by forming a P-type or N-type region by ion implantation, for example.

This configuration of the pixel2hbfor phase difference detection is similar to that of the pixels2illustrated inFIGS.25A and25B. As described with reference toFIGS.25A and25B, the pixel2hbfor phase difference detection can separately receive light coming from a left part and light coming from a right part.

The PD42-1and the PD42-2separately receive light coming from a left part and light coming from a right part, so that a focus position can be detected as described with reference toFIG.26.

The formation of recessed regions48can improve sensitivity. As illustrated inFIG.35, by forming recessed regions48for the normal pixel2haand the pixel2hbfor phase difference detection, sensitivity can be further improved.

FIG.35illustrates a G pixel on the left side and a G pixel on the right side. Like the pixel2hillustrated inFIG.34, in the pixel2hbfor phase difference detection, two PDs42are formed under one on-chip lens52b, and an intra-pixel separation portion101is formed between the two PDs42.

Furthermore, inter-pixel separation portions54are formed to surround a region including the two PDs42and the intra-pixel separation portion101. In addition, a recessed region48is formed over the region including the two PDs42and the intra-pixel separation portion101.

As in the first to seventh embodiments, the formation of the recessed region48can improve the sensitivity of the PDs42. Furthermore, as in the first to seventh embodiments, the formation of the inter-pixel separation portions54can prevent light from leaking to the adjacent pixels2hto reduce color mixing. Moreover, the inter-pixel separation portions54reflect light, providing the effect of confining the light within the pixel2h.

By the provision of the recessed region48, incident light is scattered. For example, light incident on the PD42-1is scattered and can enter the PD42-2, decreasing the degree of separation. Therefore, as illustrated inFIG.35, the recessed region48may not be formed on the intra-pixel separation portion101to make it flat.

Referring again toFIG.35, the recessed region48hformed in the pixel2hbis not formed on the intra-pixel separation portion101but is formed in a flat shape. In other words, the recessed region48his formed in open regions of the PDs42, and is not formed in regions other than the open regions. In this manner, the recessed region48hmay be formed in the open regions of the PDs42.

As described with reference toFIG.35, the recessed region48hmay be formed in each pixel2harranged in the pixel array3. Alternatively, as illustrated inFIG.36, the recessed region48hmay be formed in the normal pixel2ha, and no recessed region48hmay be formed in the pixel2hbfor phase difference detection.

Furthermore, for the pixels2hplaced at the image height center, as illustrated inFIG.35, the recessed regions48hmay be formed in both the normal pixel2haand the pixel2hbfor phase difference detection. For the pixels2hplaced at the high image height, as illustrated inFIG.36, the recessed region48hmay be formed in the normal pixel2ha, and no recessed region48hmay be formed in the pixel2hbfor phase difference detection. That is, the recessed region48hmay be formed in the pixel2hbfor phase difference detection depending on the image height.

Furthermore, the shape of the recessed region48hmay be varied (the number of valleys may be varied) depending on the image height. As described with reference toFIG.11, the pixel array3is divided into the three regions. The region A is the image height center of the pixel array3. The region B is the middle-image-height region of the pixel array3. The region C is the high-image-height region of the pixel array3.

Here, the description will be continued with a case as an example where recessed regions48hare formed in the normal pixels2haregardless of the image height, and the recessed regions48hhave the same shape. However, as is the case with the pixel2hbfor phase difference detection, the shape of the recessed regions48hmay be varied depending on the image height.

In a pixel2hbfor phase difference detection placed in the region A, a recessed region48his formed as illustrated inFIG.35. Furthermore, the number of recesses of the recessed region48hformed above one PD42is five in the example illustrated inFIG.35.

FIG.37is a cross-sectional view of pixels2hplaced in the region B (at the medium image height). As illustrated inFIG.37, a recessed region48his formed in a pixel2hbfor phase difference detection placed in the region B. Furthermore, the number of recesses of the recessed region48hformed above one PD42is three in the example illustrated inFIG.37.

FIG.38is a cross-sectional view of pixels2hplaced in the region C (at the high image height). As illustrated inFIG.38, a recessed region48his formed in a pixel2hbfor phase difference detection placed in the region C. Furthermore, the number of recesses of the recessed region48hformed above one PD42is two in the example illustrated inFIG.38.

Comparing the pixels2hbfor phase different detection illustrated inFIGS.35,37, and38with each other, the number of valleys of the recessed region48hin the pixel2hbfor phase difference detection illustrated inFIG.35, the number of valleys of the recessed region48hin the pixel2hbfor phase difference detection illustrated inFIG.37, and the number of valleys of the recessed region48hin the pixel2hbfor phase difference detection illustrated inFIG.38are different numbers.

As described above, since color mixing tends to increase with increasing image height, the number of valleys of the recessed regions48is made smaller toward the high image height side in order to reduce color mixing at the pixels2hbfor phase difference detection placed on the high image height side where color mixing increases.

Here, the pixel array3is divided into the three regions. The number of recesses of the recessed regions48hmay be discrete, such as five, three, and two, or may be continuous. In a case where the number of valleys of the recessed regions48his set continuously, it is gradually decreased with increasing image height.

Such adjustment of the number of valleys of the recessed regions48hcan reduce color mixing that can occur due to the formation the recessed regions48h. Thus, in the pixel2hbfor phase difference detection, the recessed region48hcan be formed to prevent a reduction in the degree of separation.

On the high image height side, a sensitivity difference can occur between the two PDs42formed in the pixel2hbfor phase difference detection. The shape of the recessed region48hmay be varied in a pixel for phase difference detection. For example, as illustrated inFIGS.39A and39B, the recessed region48hmay be formed above one of the PD42-1and the PD42-2and may not be formed above the other.

FIG.39Aillustrates a case where the recessed region48his formed above the PD42-1that receives light from the left direction, and no recessed region48his formed above the PD42-2that receives light from the right direction. Comparing the PD42-1and the PD42-2illustrated inFIG.39A, in a case where the sensitivity of the PD42-1is more likely to decrease than that of the PD42-2, the recessed region48his formed above the PD42-1, and no recessed region48his formed above the PD42-2. By forming the recessed region48hlike this, even in a case where the sensitivity of the PD42-1becomes lower than the sensitivity of the PD42-2, the sensitivity of the PD42-1can be improved to make the sensitivity of the PD42-1and the sensitivity of the PD42-2match.

FIG.39Billustrates a case where no recessed region48his formed above the PD42-1that receives light from the left direction, and the recessed region48his formed above the PD42-2that receives light from the right direction. Comparing the PD42-1and the PD42-2illustrated inFIG.39B, in a case where the sensitivity of the PD42-2is more likely to decrease than that of the PD42-1, the recessed region48his formed above the PD42-2, and no recessed region48his formed above the PD42-1. By forming the recessed region48hlike this, even in a case where the sensitivity of the PD42-2becomes lower than the sensitivity of the PD42-1, the sensitivity of the PD42-2can be improved to make the sensitivity of the PD42-1and the sensitivity of the PD42-2match.

By thus adjusting sensitivity by forming or not forming the recessed region48within the pixel2hbfor phase difference detection, adjustment may be made to prevent the occurrence of a sensitivity difference between the two PDs42.

Further, the number of recesses of the recessed region48may be adjusted depending on the image height. A cross-sectional view of pixels2hillustrated inFIGS.40A and40Billustrate an example of a case where a recessed region48his formed above one of the PD42-1and the PD42-2in a pixel for phase difference detection and is not formed above the other, and a case where, on the high image height side, the number of recesses of the recessed region48his changed depending on the image height as described with reference toFIGS.35,37, and38.

In the pixel2hbfor phase difference detection illustrated inFIG.40A, a recessed region48his formed above the PD42-1, and three recesses are formed in the recessed region48h. The pixels2hillustrated inFIG.40Amay be placed on the high image height side, and the pixels2hillustrated inFIG.39Amay be placed on the image height center side.

In the pixel2hbfor phase difference detection illustrated inFIG.40B, a recessed region48his formed above the PD42-2, and three recesses are formed in the recessed region48h. The pixels2hillustrated inFIG.40Bmay be placed on the high image height side, and the pixels2hillustrated inFIG.39Bmay be placed on the image height center side.

In this manner, by adjusting sensitivity by forming or not forming the recessed region48within the pixel2hbfor phase difference detection, and further adjusting the number of recesses depending on the image height, adjustment may be made to prevent the occurrence of a sensitivity difference between the two PDs42.

Thus, by providing the recessed region48in a pixel having two PDs under one on-chip lens as a pixel for phase difference detection, light can also be more efficiently collected in the PDs42, and photoelectric conversion efficiency can be improved. Further, by adjusting the shape (the number of valleys) of the recessed region48depending on the image height, sensitivity can be made uniform, and color mixing can be reduced.

Ninth Embodiment

As a ninth embodiment, another configuration of the pixels2hin the eighth embodiment will be described.

FIG.41illustrates a cross-sectional configuration example of pixels2iin the ninth embodiment. The pixels2hillustrated inFIG.35are compared with the pixels2iillustrated inFIG.41. The pixel2hbfor phase difference detection illustrated inFIG.35includes the two PDs42. The two PDs42are separated by the intra-pixel separation portion101formed in the P-type (or N-type) semiconductor region by ion implantation or the like. The pixels2iillustrated inFIG.41are different in that the intra-pixel separation portion101has a configuration similar to that of the inter-pixel separation portions54.

For the pixels2iillustrated inFIG.41, in a pixel2ibfor phase difference detection, one on-chip lens52ibis also formed over two PDs42. Furthermore, the pixel2ibfor phase difference detection includes a PD42-1and a PD42-2. An intra-pixel separation portion102is formed therebetween. The intra-pixel separation portion102has a configuration similar to that of the inter-pixel separation portions54.

By thus separating the PD42-1and the PD42-2by the intra-pixel separation portion102, light leakage between the PD42-1and the PD42-2can be prevented, and color mixing can be reduced.

The basic configuration of the pixels2iillustrated inFIG.41is similar to that of the pixels2hdescribed as the eighth embodiment. Thus, what is described as the eighth embodiment can also be applied to the pixels2iin the ninth embodiment as appropriate.

For example, the pixels2iillustrated inFIG.41can be applied to all the pixels2arranged in the pixel array3. That is, recessed regions48may be formed in all of the normal pixels2iaand the pixels2ibfor phase difference detection arranged in the pixel array3.

Furthermore, as described with reference toFIGS.35and36, recessed regions48may be formed depending on the image height. For example, for the pixels placed at the image height center, as described with reference toFIG.35, recessed regions48may be formed in both the normal pixel2iaand the pixel2ibfor phase difference detection. For the pixels placed at the high image height, as described with reference toFIG.36, a recessed region48may be formed in the normal pixel2ia, and no recessed region48may be formed in the pixel2ibfor phase difference detection.

Further, as described with reference toFIGS.35,37, and38, the number of recesses of the recessed regions48may be varied depending on the image height. Furthermore, as described with reference toFIGS.39A and39B, a recessed region48may be formed above one of the PD42-1and the PD42-2, and may not be formed above the other. Moreover, as described with reference toFIGS.40A and40B, a recessed region48may be formed above one of the PD42-1and the PD42-2, and may not be formed above the other, and the number of recesses of the recessed region48may be varied depending on the image height.

For the pixels2iin the ninth embodiment, an on-chip lens52bcovering two pixels is formed for the pixel2ibfor phase difference detection, whereas an on-chip lens52acovering one pixel is formed for the normal pixel2ia. Referring again toFIG.33, the on-chip lens52bon the pixel for phase difference detection is formed in an elliptical shape, whereas the on-chip lenses52aon the normal pixels are formed in a circular shape.

Furthermore, it is preferable that the on-chip lenses52aformed around the on-chip lens52bon the pixel for phase difference detection and the on-chip lenses52aaround which the on-chip lenses52aon the normal pixels are formed have the same shape, but may not necessarily have the same shape.

The on-chip lenses52aformed around the on-chip lens52bon the pixel for phase difference detection may have a difference in shape as compared with the on-chip lenses52on the other pixels. Due to such a difference in shape, light collection cannot be performed properly, and light can leak into adjacent pixels.

As illustrated inFIG.42, no recessed regions48imay be formed in the normal pixels2iaplaced around the pixel2ibfor phase difference detection.FIG.42illustrates five pixels including the pixel2ibfor phase difference detection among the pixels arranged in the pixel array3.

A recessed region48iis formed in the pixel2ibfor phase difference detection. No recessed regions48iare formed in the normal pixels2iaadjacent to the pixel2ibfor phase difference detection. Furthermore, recessed regions48iare formed in normal pixels2iaadjacent to the normal pixels2iain which no recessed regions48iare formed.

Thus, the recessed regions48imay be formed except in the normal pixels2iaadjacent to the pixel2ibfor phase difference detection, and no recessed regions48imay be formed in the normal pixels2iaadjacent to the pixel2ibfor phase difference detection. Such a configuration can also be applied to the pixels2hin the eighth embodiment.

FIG.42illustrates the configuration in which no recessed regions48iare formed in the normal pixels2iaadjacent to the pixel2ibfor phase difference detection. However, a recessed region48imay be formed or may not be formed depending on the light incident direction.

For example, as illustrated inFIG.43, for pixels2iplaced at positions where light enters from the left side in the figure, no recessed region48iis formed in the normal pixel2iaplaced on the left side of the pixel2ibfor phase difference detection, but a recessed region48iis formed in the normal pixel2iaplaced on the right side.

In this case, since light enters from the left side, it is considered to be likely to be affected by the pixel located on the left side. Therefore, no recessed region48iis formed in the normal pixel2iaplaced on the left side of the pixel2ibfor phase difference detection, to prevent color mixing.

In this manner, the presence or absence of a recessed region48imay be set depending on the direction of color mixing. In addition, the direction of color mixing may depend on the image height, and thus the presence or absence of a recessed region48imay be set depending on the image height.

Tenth Embodiment

The pixels2ato2cin the first to third embodiments can also be applied to pixels that detect a phase difference. A phase difference is detected, for example, to perform autofocus (AF).

Referring toFIGS.44and45, pixels for detecting a phase difference to which the present technology can be applied will be additionally described. As illustrated inFIG.44, a predetermined number of pixels in the pixel array3are allocated to pixels for phase difference detection. A plurality of phase difference detection pixels is provided at predetermined positions in the pixel array3.

InFIG.44, a phase difference detection pixel2j-1and a phase difference detection pixel2j-2are used as a pair of pixels for phase difference detection. In the pixel array3, phase difference detection pixels2jand imaging pixels2jare arranged.

The phase difference detection pixels2jare pixels used for detecting a focal point by a phase difference method. The imaging pixels2jare pixels different from the phase difference detection pixels2jand are pixels used for imaging.

An upper diagram inFIG.45illustrates a cross-sectional configuration example of pixels2jalong line A-B inFIG.44. A lower diagram inFIG.45illustrates a cross-sectional configuration example of pixels2jalong line C-D inFIG.44. The pixels2jillustrated inFIG.45are pixels to which the present technology is not applied.

Referring to the upper diagram inFIG.45, the phase difference detection pixel2j-1is surrounded by inter-pixel separation portions54. Furthermore, a light-shielding film49is formed on the inter-pixel separation portions54. A light-shielding film49j-1formed on the left side in the figure of the phase difference detection pixel2j-1is formed to a central portion of the phase difference detection pixel2j-1. The light-shielding film49-1covers almost the left half of the PD42. Thus, the phase difference detection pixel2j-1is opened on the right side and light-shielded on the left side.

Referring to the lower diagram inFIG.45, the phase difference detection pixel2j-2is also surrounded by inter-pixel separation portions54like the phase difference detection pixel2j-1. Furthermore, the light-shielding film49is formed on the inter-pixel separation portions54. A light-shielding film49j-2formed on the right side in the figure of the phase difference detection pixel2j-2is formed to a central portion of the phase difference detection pixel2j-2. The light-shielding film49-2covers almost the right half of the PD42. Thus, the phase difference detection pixel2j-2is opened on the left side and light-shielded on the right side.

The phase difference detection pixel2j-1and the phase difference detection pixel2j-2are configured to be able to separately receive light coming from a left part and light coming from a right part. The phase difference detection pixel2j-1and the phase difference detection pixel2j-2separately receive light coming from a left part and light coming from a right part, so that a focus position can be detected as described with reference toFIG.26.

The phase difference detection pixels2j, which are half light-shielded, have a lower sensitivity than the imaging pixels2jthat are not light-shielded. Therefore, by forming recessed regions48in the phase difference detection pixels2j, the sensitivity of the phase difference detection pixels2jis improved.

FIG.46is a diagram illustrating a cross-sectional configuration example of pixels2jin a tenth embodiment to which the present technology is applied. In the following description, the phase difference detection pixel2j-1will be described as an example. The phase difference detection pixel2j-2paired therewith has a similar configuration.

Furthermore, here, the description will be continued with a case where the phase difference detection pixels2jare G pixels as an example. However, the phase difference detection pixels2jmay be R pixels or B pixels. Furthermore, in a case where white pixels (W pixels) are placed, the W pixels may be used as the phase difference detection pixels2j.

In the phase difference detection pixel2j-1illustrated inFIG.46, a recessed region48jis formed. A light-shielding film49j-1is formed on the recessed region48j. In the example illustrated inFIG.46, the light-shielding film49j-1is formed in a shape in conformance with recesses and protrusions of the recessed region48j.

In a phase difference detection pixel2j-1illustrated inFIG.47, as in the phase difference detection pixel2j-1illustrated inFIG.46, a light-shielding film49j-1is formed on a recessed region48j, but the top surface (light incidence plane side) of the light-shielding film49j-1is made flat.

The light incidence plane side of the light-shielding film49j-1illustrated inFIG.46has recesses and protrusions, whereas the light incidence plane side of the light-shielding film49j-1illustrated inFIG.47is made flat. The light incidence plane side of the light-shielding film49j-1made flat reduces reflection-caused characteristic loss.

In a phase difference detection pixel2j-1illustrated inFIG.48, a recessed region48jis formed only in an open portion. In other words, no recessed region48jis formed under a light-shielding film49j-1. Both the top surface and the bottom surface of the light-shielding film49j-1illustrated inFIG.48are made flat.

The configurations illustrated inFIGS.46and47can produce space in valley portions of the recessed region48that are not filled with a material forming the light-shielding film49j-1without gaps. However, the configuration illustrated inFIG.48, in which both the top surface and the bottom surface of the light-shielding film49j-1are made flat, can reduce the possibility of producing space.

Further, the shape of the recessed region48jmay be varied (the number of valleys may be varied) depending on the image height. As described with reference toFIG.11, the pixel array3is divided into the three regions. The region A is the image height center of the pixel array3. The region B is the middle-image-height region of the pixel array3. The region C is the high-image-height region of the pixel array3.

The pixels2jplaced in the region A (at the image height center) have a structure in which no recessed region48jis formed in the phase difference detection pixel2j-1as illustrated inFIG.45.

FIG.49is a cross-sectional view of pixels2jplaced in the region B (at the medium image height). As illustrated inFIG.49, a recessed region48jis formed in an open portion of a phase difference detection pixel2j-1placed in the region B. Furthermore, the number of valleys of the recessed region48jformed is two.

FIG.50is a cross-sectional view of pixels2jplaced in the region C (at the high image height). As illustrated inFIG.50, a recessed region48jis formed in an open portion of a phase difference detection pixel2j-1placed in the region C. Furthermore, the number of valleys of the recessed region48jformed is three.

Comparing the phase difference detection pixels2j-1illustrated inFIGS.49and50, the number of the valleys of the recessed region48jin the phase difference detection pixel2j-1placed in the region B illustrated inFIG.49is different from the number of the valleys of the recessed region48jin the phase difference detection pixel2jplaced in the region C illustrated inFIG.50. The number of the valleys of the recessed region48jin the phase difference detection pixel2jplaced in the region B illustrated inFIG.49is two. The number of the valleys of the recessed region48jin the phase difference detection pixel2jplaced in the region C illustrated inFIG.50is three.

In general, sensitivity tends to decrease with increasing image height. Therefore, to increase the sensitivity of the phase difference detection pixels2jplaced on the high image height side where sensitivity becomes lower, the number of valleys of the recessed regions48is made larger than that of the phase difference detection pixels2jlocated at places other than those at the high image height.

Further, a recessed region48jmay be formed in one of the phase difference detection pixel2j-1and the phase difference detection pixel2j-2placed on the high image height side, and may not be formed in the other. On the high image height side, a difference can occur between the sensitivity of the phase difference detection pixel2j-1and the sensitivity of the phase difference detection pixel2j-2.

As illustrated inFIG.51, the pixel array3is divided into the image height left side and the image height right side. A diagram of the relationship between the incidence angle and the output of the phase difference detection pixel2j-1and the phase difference detection pixel2j-2placed on the image height left side is illustrated on the left side of the figure. A diagram of the relationship between the incidence angle and the output of the phase difference detection pixel2j-1and the phase difference detection pixel2j-2placed on the image height right side is illustrated on the right side of the figure.

In the diagrams, the horizontal axis represents the light incidence angle, and the vertical axis the pixel output value depending on incident light. Furthermore, in the diagrams, a graph indicated by a solid line represents output from the phase difference detection pixel2j-1whose left side is light-shielded, and a graph indicated by a dotted line represents output from the phase difference detection pixel2j-2whose right side is light-shielded.

The graphs illustrated inFIG.51show that each phase difference detection pixel2jhas a maximum value at an incidence angle other than zero degrees. That is, each phase difference detection pixel depends on the light incidence angle, and has a maximum value when light enters at a predetermined angle. Furthermore, the phase difference detection pixel2j-1efficiently receives light incident from the right side and obtains the maximum value, but does not receive light incident from the left side and has a small output value. Likewise, the phase difference detection pixel2j-2efficiently receives light incident from the left side and obtains the maximum value, but does not receive light incident from the right side and has a small output value.

Furthermore, referring to the graphs on the image height left side, the phase difference detection pixel2j-1and the phase difference detection pixel2j-2placed on the image height left side have different sensitivities, and the phase difference detection pixel2j-1has a higher sensitivity than the phase difference detection pixel2j-2. Likewise, referring to the graphs on the image height right side, the phase difference detection pixel2j-1and the phase difference detection pixel2j-2placed on the image height right side have different sensitivities, and the phase difference detection pixel2j-2has a higher sensitivity than the phase difference detection pixel2j-1.

When the phase difference detection pixel2j-1and the phase difference detection pixel2j-2function as a pair of phase difference detection pixels, it is preferable that such a sensitivity difference be small. Therefore, a recessed region48jis formed in one with a lower sensitivity to improve the sensitivity.

FIG.52illustrates a structure of the phase difference detection pixels2jplaced on the image height right side. On the image height right side, as in the graphs illustrated on the right side ofFIG.51, the sensitivity of the phase difference detection pixel2j-2tends to be higher than the sensitivity of the phase difference detection pixel2j-1. Therefore, as illustrated inFIG.52, no recessed region48jis formed in the phase difference detection pixel2j-2, and a recessed region48jis formed in the phase difference detection pixel2j-1.

FIG.53illustrates a structure of the phase difference detection pixels2jplaced on the image height left side. On the image height left side, as in the graphs illustrated on the left side ofFIG.51, the sensitivity of the phase difference detection pixel2j-1tends to be higher than the sensitivity of the phase difference detection pixel2j-2. Therefore, as illustrated inFIG.53, no recessed region48jis formed in the phase difference detection pixel2j-1, and a recessed region48jis formed in the phase difference detection pixel2j-2.

In this manner, the recessed region48jmay be formed only in the phase difference detection pixel2jon the lower-sensitivity side of the phase difference detection pixels2j, to adjust it to prevent the occurrence of a sensitivity difference between the pixels constituting the pair of phase difference detection pixels2j.

In the description with reference toFIGS.44to53, the case where the recessed regions48jare formed in the phase difference detection pixels2jhas been described as an example, but recessed regions48jmay be formed in the imaging pixels2jas well as in the phase difference detection pixels2jarranged in the pixel array3.

In a case where the recessed regions48jare also formed in the imaging pixels2j, the sensitivity of the imaging pixels2jis also improved. The improved sensitivity of the imaging pixels2jadjacent to the phase difference detection pixels2jcan increase color mixing into the phase difference detection pixels2j.

With reference toFIGS.54and55, a case where recessed regions48jare also formed in the imaging pixels2jwill be additionally described. As illustrated inFIG.54, a predetermined number of pixels in the pixel array3are allocated to phase difference detection pixels. InFIG.54, a phase difference detection pixel2j-1and a phase difference detection pixel2j-2are used as a pair of pixels for phase difference detection. Recessed regions48jare formed in the phase difference detection pixel2j-1and the phase difference detection pixel2j-2as described above.

In the pixel array3, the imaging pixels2jare placed around the phase difference detection pixels2j. An upper diagram inFIG.55illustrates a cross-sectional configuration example of pixels2jalong line E-F inFIG.54. A lower diagram inFIG.55illustrates a cross-sectional configuration example of pixels2jalong line G-H inFIG.54.

Referring to the upper diagram inFIG.55, a recessed region48jis formed in the phase difference detection pixel2j-2. Recessed regions48j, each with one recess, are also formed in an imaging pixel2j′-1and an imaging pixel2j′-2located on the left side of the phase difference detection pixel2j-2. Furthermore, a recessed region48jwith six recesses is formed in an imaging pixel2j′-3located on the right side of the imaging pixel2j′-2.

Thus, the number of the recesses of the recessed regions48jin the imaging pixel2j′-1and the imaging pixel2j′-2adjacent to the phase difference detection pixel2j-2is smaller than the number of the recesses of the recessed region48jin the imaging pixel2j′-3not adjacent to the phase difference detection pixel2j-2.

Referring to the lower diagram inFIG.55, the imaging pixel2j′-1is adjacent to the phase difference detection pixel2j-2, and thus the number of recesses of the recessed region48jin the imaging pixel2j′-1is one. Furthermore, an imaging pixel2j′-5is adjacent to the phase difference detection pixel2j-1, and thus the number of recesses of a recessed region48jin the imaging pixel2j′-5is one.

An imaging pixel2j′-4is adjacent to the phase difference detection pixel2j-1in an oblique direction, and thus the number of recesses of a recessed region48jin the imaging pixel2j′-4is three. An imaging pixel2j′-6is adjacent to the phase difference detection pixel2j-2in an oblique direction, and thus the number of recesses of a recessed region48jin the imaging pixel2j′-6is three.

Thus, the number of the recesses of the recessed region48jin the imaging pixel2j′-4adjacent to the phase difference detection pixel2j-1in the oblique direction is smaller than the number of the recesses of the recessed region48jin the imaging pixels2j′ (for example, the imaging pixel2j′-3illustrated in the upper diagram ofFIG.55) not adjacent to the phase difference detection pixel2j-1, and is larger than the number of the recesses of the recessed region48jin the imaging pixel2j′-5adjacent to the phase difference detection pixel2j-1.

Likewise, the number of the recesses of the recessed region48jin the imaging pixel2j′-6adjacent to the phase difference detection pixel2j-2in the oblique direction is smaller than the number of the recesses of the recessed region48jin the imaging pixel2j′-3not adjacent to the phase difference detection pixel2j-2, and is larger than the number of the recesses of the recessed region48jin the imaging pixel2j′-1adjacent to the phase difference detection pixel2j-2.

In the structure illustrated inFIG.55, the number of recesses of the recessed region48in each pixel adjacent to the phase difference detection pixel2jin the up, down, left, or right direction is the smallest, and the number of recesses of the recessed region48in each pixel adjacent to the phase difference detection pixel2jin the oblique direction is the next smallest.

The number of recesses of the recessed region48in each pixel adjacent to the phase difference detection pixel2jin the up, down, left, or right direction may be the same as the number of recesses of the recessed region48in each pixel adjacent to the phase difference detection pixel2jin the oblique direction.

Furthermore, no recessed region48may be formed in each pixel adjacent to the phase difference detection pixel2jin the up, down, left, or right direction and each pixel adjacent to the phase difference detection pixel2jin the oblique direction.

The tenth embodiment may be combined with the fourth to ninth embodiments. The fourth to ninth embodiments can be applied to a system in which light from a left part and light from a right part are separately received by two PDs42. By light-shielding one of the two PDs42and not light-shielding the other, it can be treated the same as the phase difference detection pixel2jin the tenth embodiment.

For example,FIG.56illustrates a case where the pixels2fin the sixth embodiment illustrated inFIG.17are combined with those in the tenth embodiment. In a cross-sectional structure example illustrated inFIG.56, a B pixel illustrated on the right side in the figure is a phase difference detection pixel2f′. A light-shielding film49′ in the phase difference detection pixel2f′ is formed to a position to cover almost the left half of a PD42-1formed in the B pixel.

That is, in the B pixel illustrated inFIG.56, the PD42-1is light-shielded, and a PD42-2is opened. This structure is similar to the structure of the phase difference detection pixel2j-1illustrated inFIG.48, for example, and is a structure in which the left side is light-shielded. Thus, the B pixel whose left side is light-shielded may be used as a phase difference detection pixel.

In the example illustrated inFIG.56, no recessed region48is formed in a G pixel adjacent to the B pixel functioning as a phase difference detection pixel, but it may be formed.

The tenth embodiment can thus be combined with the embodiments inFIGS.4,5,6A,6B,7,8, and9. In addition, what is described as the tenth embodiment, for example, an embodiment in which the number of recesses of the recessed regions48is varied depending on the image height can be applied to the combined embodiment.

<Example of Application to Electronic Apparatus>

The technology of the present disclosure is not limited to application to a solid-state imaging apparatus. Specifically, the technology of the present disclosure is applicable to all electronic apparatuses using a solid-state imaging apparatus for an image capturing unit (photoelectric conversion part), such as imaging apparatuses including digital still cameras and video cameras, portable terminal devices having an imaging function, and copying machines using a solid-state imaging apparatus for an image reading unit. The solid-state imaging apparatus may be formed as one chip, or may be in a modular form having an imaging function in which an imaging unit and a signal processing unit or an optical system are packaged together.

FIG.57is a block diagram illustrating a configuration example of an imaging apparatus as an electronic apparatus according to the present disclosure.

An imaging apparatus500inFIG.57includes an optical unit501including a lens group or the like, a solid-state imaging apparatus (imaging device)502in which the configuration of the solid-state imaging apparatus1inFIG.1is used, and a digital signal processor (DSP) circuit503that is a camera signal processing circuit. Furthermore, the imaging apparatus500also includes a frame memory504, a display unit505, a recording unit506, an operation unit507, and a power supply508. The DSP circuit503, the frame memory504, the display unit505, the recording unit506, the operation unit507, and the power supply508are mutually connected via a bus line509.

The optical unit501captures incident light (image light) from a subject, forming an image on an imaging surface of the solid-state imaging apparatus502. The solid-state imaging apparatus502converts the amount of incident light formed as the image on the imaging surface by the optical unit501into an electric signal pixel by pixel and outputs the electric signal as a pixel signal. As the solid-state imaging apparatus502, the solid-state imaging apparatus1inFIG.1, that is, a solid-state imaging apparatus that improves sensitivity while preventing worsening of color mixing can be used.

The display unit505includes, for example, a panel display device such as a liquid crystal panel or an organic electroluminescent (EL) panel, and displays moving images or still images captured by the solid-state imaging apparatus502. The recording unit506records a moving image or a still image captured by the solid-state imaging apparatus502on a recording medium such as a hard disk or a semiconductor memory.

The operation unit507issues operation commands on various functions of the imaging apparatus500under user operation. The power supply508appropriately supplies various power supplies to be operation power supplies for the DSP circuit503, the frame memory504, the display unit505, the recording unit506, and the operation unit507, to them to be supplied with.

As described above, using the above-described solid-state imaging apparatus1as the solid-state imaging apparatus502can improve sensitivity while preventing worsening of color mixing. Therefore, the imaging apparatus500such as a video camera or a digital still camera, or further a camera module for a mobile device such as a portable phone can also improve the quality of captured images.

Note that embodiments of the present disclosure are not limited to the above-described embodiments, and various changes may be made without departing from the scope of the present disclosure.

In the above-described examples, the solid-state imaging apparatus that uses electrons as signal charges with the first conductivity type as P-type and the second conductivity type as N-type has been described. The present disclosure is also applicable to a solid-state imaging apparatus that uses holes as signal charges. That is, with the first conductivity type as N-type and the second conductivity type as P-type, each semiconductor region described above can be formed by a semiconductor region of the opposite conductivity type.

Furthermore, the technology of the present disclosure is not limited to the application to a solid-state imaging apparatus that detects the distribution of the amount of incident light of visible light and captures it as an image, and can be applied to a solid-state imaging apparatus that captures the distribution of the amount of incident infrared rays, X-rays, particles, or the like as an image, and, in a broad sense, to all solid-state imaging apparatuses (physical quantity distribution detection devices) such as a fingerprint detection sensor which detect the distribution of another physical quantity such as pressure or capacitance and capture it as an image.

<Example of Application to Endoscopic Surgery System>

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

FIG.58is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

FIG.58illustrates a state in which an operator (doctor)11131is performing an operation on a patient11132on a patient bed11133, using an endoscopic surgery system11000. As illustrated in the figure, the endoscopic surgery system11000includes an endoscope11100, other surgical instruments11110including an insufflation tube11111and an energy treatment instrument11112, a support arm device11120that supports the endoscope11100, and a cart11200on which various devices for endoscopic surgery are mounted.

The endoscope11100includes a lens tube11101with a region of a predetermined length from the distal end inserted into the body cavity of the patient11132, and a camera head11102connected to the proximal end of the lens tube11101. In the illustrated example, the endoscope11100formed as a so-called rigid scope having a rigid lens tube11101is illustrated, but the endoscope11100may be formed as a so-called flexible scope having a flexible lens tube.

An opening in which an objective lens is fitted is provided at the distal end of the lens tube11101. A light source device11203is connected to the endoscope11100. Light generated by the light source device11203is guided to the distal end of the lens tube11101through a light guide extended inside the lens tube11101, and is emitted through the objective lens toward an object to be observed in the body cavity of the patient11132. Note that the endoscope11100may be a forward-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

An optical system and an imaging device are provided inside the camera head11102. Light reflected from the object being observed (observation light) is concentrated onto the imaging device by the optical system. The observation light is photoelectrically converted by the imaging device, and an electric signal corresponding to the observation light, that is, an image signal corresponding to an observation image is generated. The image signal is transmitted to a camera control unit (CCU)11201as RAW data.

The CCU11201includes a central processing unit (CPU), a graphics processing unit (GPU), or the like, and performs centralized control on the operations of the endoscope11100and a display device11202. Moreover, the CCU11201receives an image signal from the camera head11102, and performs various types of image processing such as development processing (demosaicing) on the image signal for displaying an image based on the image signal.

The display device11202displays an image based on an image signal subjected to image processing by the CCU11201under the control of the CCU11201.

The light source device11203includes a light source such as a light-emitting diode (LED), and supplies irradiation light when a surgical site or the like is imaged to the endoscope11100.

An input device11204is an input interface for the endoscopic surgery system11000. The user can input various types of information and input instructions to the endoscopic surgery system11000via the input device11204. For example, the user inputs an instruction to change conditions of imaging by the endoscope11100(the type of irradiation light, magnification, focal length, etc.) and the like.

A treatment instrument control device11205controls the drive of the energy treatment instrument11112for tissue ablation, incision, blood vessel sealing, or the like. An insufflation device11206feeds gas into the body cavity of the patient11132through the insufflation tube11111to inflate the body cavity for the purpose of providing a field of view by the endoscope11100and providing the operator's workspace. A recorder11207is a device that can record various types of information associated with surgery. A printer11208is a device that can print various types of information associated with surgery in various forms including text, an image, and a graph.

Note that the light source device11203that supplies irradiation light when a surgical site is imaged to the endoscope11100may include a white light source including LEDs, laser light sources, or a combination of them, for example. In a case where a white light source includes a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high accuracy. Thus, the light source device11203can adjust the white balance of captured images. Furthermore, in this case, by irradiating an object to be observed with laser light from each of the RGB laser light sources in a time-division manner, and controlling the drive of the imaging device of the camera head11102in synchronization with the irradiation timing, images corresponding one-to-one to RGB can also be imaged in a time-division manner. According to this method, color images can be obtained without providing color filters at the imaging device.

Furthermore, the drive of the light source device11203may be controlled so as to change the intensity of output light every predetermined time. By controlling the drive of the imaging device of the camera head11102in synchronization with the timing of change of the intensity of light and acquiring images in a time-division manner, and combining the images, a high dynamic range image without so-called underexposure and overexposure can be generated.

Furthermore, the light source device11203may be configured to be able to supply light in a predetermined wavelength band suitable for special light observation. In special light observation, for example, so-called narrow band imaging is performed in which predetermined tissue such as a blood vessel in a superficial portion of a mucous membrane is imaged with high contrast by irradiating it with light in a narrower band than irradiation light at the time of normal observation (that is, white light), utilizing the wavelength dependence of light absorption in body tissue. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained by fluorescence generated by irradiation with excitation light. Fluorescence observation allows observation of fluorescence from body tissue by irradiating the body tissue with excitation light (autofluorescence observation), acquisition of a fluorescence image by locally injecting a reagent such as indocyanine green (ICG) into body tissue and irradiating the body tissue with excitation light corresponding to the fluorescence wavelength of the reagent, and the like. The light source device11203can be configured to be able to supply narrowband light and/or excitation light suitable for such special light observation.

FIG.59is a block diagram illustrating an example of a functional configuration of the camera head11102and the CCU11201illustrated inFIG.58.

The camera head11102includes a lens unit11401, an imaging unit11402, a drive unit11403, a communication unit11404, and a camera head control unit11405. The CCU11201includes a communication unit11411, an image processing unit11412, and a control unit11413. The camera head11102and the CCU11201are communicably connected to each other by a transmission cable11400.

The lens unit11401is an optical system provided at a portion connected to the lens tube11101. Observation light taken in from the distal end of the lens tube11101is guided to the camera head11102and enters the lens unit11401. The lens unit11401includes a combination of a plurality of lenses including a zoom lens and a focus lens.

The imaging unit11402may include a single imaging device (be of a so-called single plate type), or may include a plurality of imaging devices (be of a so-called multi-plate type). In a case where the imaging unit11402is of the multi-plate type, for example, image signals corresponding one-to-one to RGB may be generated by imaging devices, and they may be combined to obtain a color image. Alternatively, the imaging unit11402may include a pair of imaging devices for acquiring right-eye and left-eye image signals corresponding to a 3D (dimensional) display, individually. By performing 3D display, the operator11131can more accurately grasp the depth of living tissue at a surgical site. Note that in a case where the imaging unit11402is of the multi-plate type, a plurality of lens units11401may be provided for the corresponding imaging devices.

Furthermore, the imaging unit11402may not necessarily be provided in the camera head11102. For example, the imaging unit11402may be provided inside the lens tube11101directly behind the objective lens.

The drive unit11403includes an actuator, and moves the zoom lens and the focus lens of the lens unit11401by a predetermined distance along the optical axis under the control of the camera head control unit11405. With this, the magnification and focus of an image captured by the imaging unit11402can be adjusted as appropriate.

The communication unit11404includes a communication device for transmitting and receiving various types of information to and from the CCU11201. The communication unit11404transmits an image signal obtained from the imaging unit11402as RAW data to the CCU11201via the transmission cable11400.

Furthermore, the communication unit11404receives a control signal for controlling the drive of the camera head11102from the CCU11201, and provides the control signal to the camera head control unit11405. The control signal includes, for example, information regarding imaging conditions such as information specifying the frame rate of captured images, information specifying the exposure value at the time of imaging, and/or information specifying the magnification and focus of captured images.

Note that the imaging conditions such as the frame rate, the exposure value, the magnification, and the focus described above may be appropriately specified by the user, or may be automatically set by the control unit11413of the CCU11201on the basis of an acquired image signal. In the latter case, so-called an auto exposure (AE) function, an auto focus (AF) function, and an auto white balance (AWB) function are mounted on the endoscope11100.

The camera head control unit11405controls the drive of the camera head11102on the basis of a control signal from the CCU11201received via the communication unit11404.

The communication unit11411includes a communication device for transmitting and receiving various types of information to and from the camera head11102. The communication unit11411receives an image signal transmitted from the camera head11102via the transmission cable11400.

Furthermore, the communication unit11411transmits a control signal for controlling the drive of the camera head11102to the camera head11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

The image processing unit11412performs various types of image processing on an image signal that is RAW data transmitted from the camera head11102.

The control unit11413performs various types of control for imaging of a surgical site or the like by the endoscope11100and display of a captured image obtained by imaging of a surgical site or the like. For example, the control unit11413generates a control signal for controlling the drive of the camera head11102.

Furthermore, the control unit11413causes the display device11202to display a captured image showing a surgical site or the like, on the basis of an image signal subjected to image processing by the image processing unit11412. At this time, the control unit11413may recognize various objects in the captured image using various image recognition techniques. For example, by detecting the shape of the edge, the color, or the like of an object included in a captured image, the control unit11413can recognize a surgical instrument such as forceps, a specific living body part, bleeding, mist when the energy treatment instrument11112is used, and so on. When causing the display device11202to display a captured image, the control unit11413may superimpose various types of surgery support information on an image of the surgical site for display, using the recognition results. By the surgery support information being superimposed and displayed, and presented to the operator11131, the load of the operator11131can be reduced, and the operator11131can reliably proceed with the surgery.

The transmission cable11400that connects the camera head11102and the CCU11201is an electric signal cable for electric signal communication, an optical fiber for optical communication, or a composite cable for them.

Here, in the illustrated example, communication is performed by wire using the transmission cable11400, but communication between the camera head11102and the CCU11201may be performed by radio.

<Example of Application to Mobile Object>

The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be implemented as an apparatus mounted on any type of mobile object such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

FIG.60is a block diagram illustrating a schematic configuration example of a vehicle control system that is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

A vehicle control system12000includes a plurality of electronic control units connected via a communication network12001. In the example illustrated inFIG.60, the vehicle control system12000includes a drive system control unit12010, a body system control unit12020, a vehicle exterior information detection unit12030, a vehicle interior information detection unit12040, and an integrated control unit12050. Furthermore, as a functional configuration of the integrated control unit12050, a microcomputer12051, a sound and image output unit12052, and an in-vehicle network interface (I/F)12053are illustrated.

The drive system control unit12010controls the operation of apparatuses related to the drive system of the vehicle, according to various programs. For example, the drive system control unit12010functions as a control device for a driving force generation apparatus for generating a driving force of the vehicle such as an internal combustion engine or a drive motor, a driving force transmission mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating a vehicle braking force, etc.

The body system control unit12020controls the operation of various apparatuses mounted on the vehicle body, according to various programs. For example, the body system control unit12020functions as a control device for a keyless entry system, a smart key system, power window devices, or various lamps including headlamps, back lamps, brake lamps, indicators, and fog lamps. In this case, the body system control unit12020can receive the input of radio waves transmitted from a portable device that substitutes for a key or signals from various switches. The body system control unit12020receives the input of these radio waves or signals, and controls door lock devices, the power window devices, the lamps, etc. of the vehicle.

The vehicle exterior information detection unit12030detects information regarding the exterior of the vehicle equipped with the vehicle control system12000. For example, an imaging unit12031is connected to the vehicle exterior information detection unit12030. The vehicle exterior information detection unit12030causes the imaging unit12031to capture an image outside the vehicle and receives the captured image. The vehicle exterior information detection unit12030may perform object detection processing or distance detection processing on a person, a vehicle, an obstacle, a sign, characters on a road surface, or the like, on the basis of the received image.

The imaging unit12031is an optical sensor that receives light and outputs an electric signal corresponding to the amount of the received light. The imaging unit12031may output an electric signal as an image, or may output it as distance measurement information. Furthermore, light received by the imaging unit12031may be visible light, or may be invisible light such as infrared rays.

The vehicle interior information detection unit12040detects information of the vehicle interior. For example, a driver condition detection unit12041that detects a driver's conditions is connected to the vehicle interior information detection unit12040. The driver condition detection unit12041includes, for example, a camera that images the driver. The vehicle interior information detection unit12040may calculate the degree of fatigue or the degree of concentration of the driver, or may determine whether the driver is dozing, on the basis of detected information input from the driver condition detection unit12041.

The microcomputer12051can calculate a control target value for the driving force generation apparatus, the steering mechanism, or the braking device on the basis of vehicle interior or exterior information acquired by the vehicle exterior information detection unit12030or the vehicle interior information detection unit12040, and output a control command to the drive system control unit12010. For example, the microcomputer12051can perform cooperative control for the purpose of implementing the functions of an advanced driver assistance system (ADAS) including vehicle collision avoidance or impact mitigation, following driving based on inter-vehicle distance, vehicle speed-maintaining driving, vehicle collision warning, vehicle lane departure warning, and so on.

Furthermore, the microcomputer12051can perform cooperative control for the purpose of automatic driving for autonomous travelling without a driver's operation, by controlling the driving force generation apparatus, the steering mechanism, the braking device, or others, on the basis of information around the vehicle acquired by the vehicle exterior information detection unit12030or the vehicle interior information detection unit12040.

Moreover, the microcomputer12051can output a control command to the body system control unit12030on the basis of vehicle exterior information acquired by the vehicle exterior information detection unit12030. For example, the microcomputer12051can perform cooperative control for the purpose of preventing glare by controlling the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the vehicle exterior information detection unit12030, switching high beam to low beam, or the like.

The sound/image output unit12052transmits an output signal of at least one of a sound or an image to an output device that can visually or auditorily notify a vehicle occupant or the outside of the vehicle of information. In the example ofFIG.60, as the output device, an audio speaker12061, a display unit12062, and an instrument panel12063are illustrated. The display unit12062may include at least one of an on-board display or a head-up display, for example.

FIG.61is a diagram illustrating an example of the installation position of the imaging unit12031.

The imaging units12101,12102,12103,12104, and12105are provided, for example, at positions such as the front nose, the side mirrors, the rear bumper or the back door, and an upper portion of the windshield in the vehicle compartment of the vehicle12100. The imaging unit12101provided at the front nose and the imaging unit12105provided at the upper portion of the windshield in the vehicle compartment mainly acquire images of the front of the vehicle12100. The imaging units12102and12103provided at the side mirrors mainly acquire images of the sides of the vehicle12100. The imaging unit12104provided at the rear bumper or the back door mainly acquires images of the rear of the vehicle12100. The imaging unit12105provided at the upper portion of the windshield in the vehicle interior is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

Note thatFIG.61illustrates an example of imaging ranges of the imaging units12101to12104. An imaging range12111indicates the imaging range of the imaging unit12101provided at the front nose, imaging ranges12112and12113indicate the imaging ranges of the imaging units12102and12103provided at the side mirrors, respectively, and an imaging range12114indicates the imaging range of the imaging unit12104provided at the rear bumper or the back door. For example, by superimposing image data captured by the imaging units12101to12104on each other, an overhead image of the vehicle12100viewed from above is obtained.

At least one of the imaging units12101to12104may have a function of acquiring distance information. For example, at least one of the imaging units12101to12104may be a stereo camera including a plurality of imaging devices, or may be an imaging device including pixels for phase difference detection.

For example, the microcomputer12051can determine distances to three-dimensional objects in the imaging ranges12111to12114, and temporal changes in the distances (relative speeds to the vehicle12100), on the basis of distance information obtained from the imaging units12101to12104, thereby extracting, as a preceding vehicle, especially the nearest three-dimensional object located on the traveling path of the vehicle12100which is a three-dimensional object traveling at a predetermined speed (e.g., 0 km/h or higher) in almost the same direction as the vehicle12100. Furthermore, the microcomputer12051can perform automatic brake control (including following stop control), automatic acceleration control (including following start control), and the like, setting an inter-vehicle distance to be provided in advance in front of a preceding vehicle. Thus, cooperative control for the purpose of autonomous driving for autonomous traveling without a driver's operation or the like can be performed.

For example, the microcomputer12051can extract three-dimensional object data regarding three-dimensional objects, classifying them into a two-wheel vehicle, an ordinary vehicle, a large vehicle, a pedestrian, and another three-dimensional object such as a power pole, on the basis of distance information obtained from the imaging units12101to12104, for use in automatic avoidance of obstacles. For example, for obstacles around the vehicle12100, the microcomputer12051distinguishes between obstacles that can be visually identified by the driver of the vehicle12100and obstacles that are difficult to visually identify. Then, the microcomputer12051determines a collision risk indicating the degree of danger of collision with each obstacle. In a situation where the collision risk is equal to or higher than a set value and there is a possibility of collision, the microcomputer12051can perform driving assistance for collision avoidance by outputting a warning to the driver via the audio speaker12061or the display unit12062, or performing forced deceleration or avoidance steering via the drive system control unit12010.

At least one of the imaging units12101to12104may be an infrared camera that detects infrared rays. For example, the microcomputer12051can recognize a pedestrian by determining whether or not a pedestrian is present in captured images of the imaging units12101to12104. The recognition of a pedestrian is performed, for example, by a procedure of extracting feature points in captured images of the imaging units12101to12104as infrared cameras, and a procedure of performing pattern matching on a series of feature points indicating the outline of an object to determine whether or not the object is a pedestrian. When the microcomputer12051determines that a pedestrian is present in captured images of the imaging units12101to12104and recognizes the pedestrian, the sound/image output unit12052controls the display unit12062to superimpose and display a rectangular outline for enhancement on the recognized pedestrian. Alternatively, the sound/image output unit12052may control the display unit12062so as to display an icon or the like indicating the pedestrian at a desired position.

In the present description, a system represents a whole apparatus including a plurality of devices.

Note that the effects described in the present description are merely examples and nonlimiting, and other effects may be included.

Note that embodiments of the present technology are not limited to the above-described embodiments, and various changes may be made without departing from the scope of the present technology.

A solid-state imaging apparatus including:a substrate;a plurality of photoelectric conversion regions provided in the substrate;a color filter provided on an upper side of the photoelectric conversion regions;a trench provided through the substrate and provided between the photoelectric conversion regions; anda recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions,in which the color filter over adjacent two of the photoelectric conversion regions is of the same color.

The solid-state imaging apparatus according to (1) above, in whichthe number of the recesses of the recessed region is larger at a high image height than at an image height center.

The solid-state imaging apparatus according to (1) or (2) above, in whichthe recessed region is formed above one of the adjacent two of the photoelectric conversion regions.

The solid-state imaging apparatus according to any one of (1) to (3) above, in whichthe recessed region is formed above the photoelectric conversion regions over which the color filter of a second color is placed adjacent to the photoelectric conversion regions over which the color filter of a first color is placed.

A solid-state imaging apparatus including:a substrate;a plurality of photoelectric conversion regions provided in the substrate;a color filter provided on an upper side of the photoelectric conversion regions;an on-chip lens provided on an upper side of the color filter;a trench provided through the substrate, the trench surrounding four of the photoelectric conversion regions; anda recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions,in which the color filter over the four of the photoelectric conversion regions is of the same color, andthe on-chip lens is provided over the four of the photoelectric conversion regions.

The solid-state imaging apparatus according to (5) above, in whichthe number of the recesses of the recessed region is larger at a high image height than at an image height center.

The solid-state imaging apparatus according to (5) or (6) above, in whichthe recessed region is formed above at least one of the four of the photoelectric conversion regions.

The solid-state imaging apparatus according to any one of (5) to (7) above, in whichthe number of the recesses of the recessed region varies depending on a color of the color filter.

A solid-state imaging apparatus including:a substrate;a plurality of photoelectric conversion regions provided in the substrate;a color filter provided on an upper side of the photoelectric conversion regions;an on-chip lens provided on an upper side of the color filter;a trench provided through the substrate, the trench surrounding adjacent two of the photoelectric conversion regions; anda recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions,in which the color filter over the two of the photoelectric conversion regions is of the same color, andthe on-chip lens is provided over the two of the photoelectric conversion regions.

The solid-state imaging apparatus according to (9) above, in whichthe number of the recesses of the recessed region is smaller at a high image height than at an image height center.

The solid-state imaging apparatus according to (9) or (10) above, in whichthe size of the recesses of the recessed region is larger at a high image height than at an image height center.

The solid-state imaging apparatus according to any one of (9) to (11) above, in whichthe recessed region is formed above at least one of the two of the photoelectric conversion regions.

The solid-state imaging apparatus according to any one of (9) to (12) above, in whicha P-type or N-type region is provided between the two of the photoelectric conversion regions.

The solid-state imaging apparatus according to any one of (9) to (13) above, in whicha trench is provided between the two of the photoelectric conversion regions.

The solid-state imaging apparatus according to any one of (9) to (14) above, in whichthe recessed region is not formed in a second pixel at which the on-chip lens is provided over one of the photoelectric conversion regions, the second pixel being adjacent to a first pixel at which the on-chip lens is provided over the two of the photoelectric conversion regions.

The solid-state imaging apparatus according to (15) above, in whichthe recessed region is not formed in the second pixel located in a light incident direction.

A solid-state imaging apparatus including:a substrate;a plurality of photoelectric conversion regions provided in the substrate;a color filter provided on an upper side of the photoelectric conversion regions;a trench provided through the substrate and provided between the photoelectric conversion regions;a metal film covering almost a half region of the photoelectric conversion regions on an upper side of the photoelectric conversion regions; anda recessed region including a plurality of recesses provided on a light-receiving surface side of the substrate above the photoelectric conversion regions.

The solid-state imaging apparatus according to (17) above, in whichthe number of the recesses of the recessed region is larger at a high image height than at an image height center.

The solid-state imaging apparatus according to (17) or (18) above, in whichthe recessed region is provided only in either a first pixel in which the metal film covers a left half of the photoelectric conversion regions or a second pixel in which the metal film covers a right half of the photoelectric conversion regions, depending on arrangement positions in a pixel array.

The solid-state imaging apparatus according to any one of (17) to (19) above, in whichthe number of the recesses of the recessed region above the adjacent photoelectric conversion regions where the photoelectric conversion regions are not covered by the metal film is smaller than the number of the recesses of the recessed region provided above another photoelectric conversion region.

REFERENCE SIGNS LIST