JP2021072295A - Solid-state imaging device and electronic device - Google Patents

Abstract

To improve photoelectric conversion efficiency.SOLUTION: A solid-state imaging comprises: a photoelectric conversion unit provided on a semiconductor substrate; a first insulation film positioned on an incidence surface side of light to the photoelectric conversion unit relative to the semiconductor substrate; and an uneven structure positioned between the photoelectric conversion unit and the first insulation film; and the uneven structure is positioned on the photoelectric conversion unit side, and comprises a first layer which diffracts light incident on the photoelectric conversion unit; and a second layer which is positioned on the first insulation film side and suppresses reflection toward the first insulation film side.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to a solid-state image sensor and an electronic device.

Conventionally, in electronic devices having an imaging function such as a digital still camera and a digital video camera, a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor has been used.

Further, in recent years, a distance image sensor that measures a distance by a ToF (Time-of-Flight) method has attracted attention. For example, as a distance image sensor, a solid-state image sensor formed so that a plurality of SPAD (Single Photon Avalanche Diode) pixels are arranged in a plane can be used by using CMOS semiconductor integrated circuit technology. In the SPAD pixel, avalanche amplification occurs when one photon enters the PN junction region of a high electric field in a state where a voltage much larger than the yield voltage is applied. By detecting the time when the current flows momentarily at that time, the distance can be measured with high accuracy.

Japanese Unexamined Patent Publication No. 2018-88532 Japanese Unexamined Patent Publication No. 2006-147991 Japanese Unexamined Patent Publication No. 2004-47682 International Publication No. 16/194654

With respect to the solid-state image pickup device as described above, it is desired to improve the photoelectric conversion efficiency in the photoelectric conversion element that converts incident light into electric charges in order to improve the image quality, distance measurement accuracy, and the like.

Therefore, the present disclosure proposes a solid-state image sensor and an electronic device capable of improving the photoelectric conversion efficiency.

In order to solve the above problems, the solid-state imaging apparatus according to the present disclosure has a photoelectric conversion unit provided on the semiconductor substrate and a light incident surface side of the semiconductor substrate on the photoelectric conversion unit. It includes a first insulating film located and a concavo-convex structure located between the photoelectric conversion unit and the first insulating film, and the concavo-convex structure is located on the photoelectric conversion unit side and is incident on the photoelectric conversion unit. A first layer for diffusing the light to be generated and a second layer located on the first insulating film side and suppressing reflection to the first insulating film side are provided.

It is a block diagram which shows the schematic configuration example of the electronic device equipped with the solid-state image sensor which concerns on 1st Embodiment. It is a block diagram which shows the schematic structure example of the solid-state image sensor which concerns on 1st Embodiment. It is a circuit diagram which shows the schematic structure example of the unit pixel which concerns on 1st Embodiment. It is a figure which shows the example of the laminated structure of the solid-state image sensor which concerns on 1st Embodiment. It is sectional drawing which shows the example of the sectional structure of the solid-state image sensor which concerns on 1st Embodiment. It is sectional drawing which shows the uneven structure formed on the light receiving surface of a photodiode in 1st Embodiment. It is a top layout view which shows an example of the 1st layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows another example of the 1st layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows an example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is a top layout view which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is sectional drawing which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is sectional drawing which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 1st Embodiment. It is sectional drawing which shows the uneven structure formed on the light receiving surface of a photodiode in the 2nd Embodiment. It is sectional drawing which shows the other example of the 2nd layer in the concavo-convex structure which concerns on 2nd Embodiment. It is sectional drawing which shows still another example of the 2nd layer in the concavo-convex structure which concerns on 2nd Embodiment. It is sectional drawing for demonstrating the pupil correction which concerns on 1st and 2nd Embodiment. It is a figure which listed side by side the example of the cross-sectional structure of the layer structure which concerns on a comparative example, and the layer structure which concerns on 1st and 2nd Embodiment. The FDTD method is used to determine the intensity of light in each cross section when incident light is incident on the light receiving surface in the direction perpendicular to the light receiving surface (from top to bottom in the drawing) with respect to the cross-sectional structures shown in FIGS. 20 (a) to 20 (e). It is a figure which shows the result calculated in. It is a graph which shows the result of having calculated the reflectance to the upper side with respect to the layer structure shown by (a) to (e) of FIG. It is a graph which shows the result of having calculated the average light intensity from the light receiving surface to the boundary surface with the upper surface layer of a semiconductor substrate up to 2 μm in the depth direction. It is a layout figure which shows an example of the color filter array which is a Bayer array. It is sectional drawing which shows the example of the sectional structure of the unit pixel combined with the color filter which selectively transmits the wavelength component of red (R) which concerns on 1st and 2nd Embodiment. It is sectional drawing which shows the sectional structure example of the unit pixel combined with the color filter which selectively transmits the wavelength component of green (G) which concerns on 1st and 2nd Embodiment. It is sectional drawing which shows the example of the sectional structure of the unit pixel combined with the color filter which selectively transmits the wavelength component of blue (B) which concerns on 1st and 2nd Embodiment. It is a graph which shows the relationship between the wavelength of the incident light and the pitch of an uneven structure which concerns on 1st and 2nd Embodiment. It is a graph which shows the relationship between the wavelength of the incident light which concerns on 1st and 2nd Embodiment, and the height of the downward convex part in the 1st layer of the concavo-convex structure. It is a graph which shows the relationship when the wavelength of the incident light which concerns on 1st and 2nd Embodiment and the volume occupancy ratio of the lower convex part in the 1st layer of the concavo-convex structure are 1: 1. It is a block diagram which shows an example of the schematic structure of a vehicle control system. It is explanatory drawing which shows an example of the installation position of the vehicle exterior information detection unit and the image pickup unit. It is a figure which shows an example of the schematic structure of the endoscopic surgery system. It is a block diagram which shows an example of the functional structure of a camera head and a CCU.

Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same parts are designated by the same reference numerals, so that duplicate description will be omitted.

In addition, the present disclosure will be described according to the order of items shown below.
1. 1. Introduction 2. 1st Embodiment 2.1 Configuration example of electronic device 2.2 Configuration example of solid-state image sensor 2.3 Configuration example of unit pixel 2.4 Basic function example of unit pixel 2.5 Stacked structure example of solid-state image sensor 2 .6 Example of cross-sectional structure of unit pixel 2.7 Concavo-convex structure 2.7.1 Structural example of the first layer 2.7.2 Structural example of the second layer 2.8 Action / effect 3. 2nd Embodiment 3.1 Concavo-convex structure 3.11 Structural example of 1st layer 31.2 Structural example of 2nd layer 3.2 Action / effect 4. About pupil correction 5. Comparison result 6. Target wavelength band 7. Manufacturing method of uneven structure 8. Combination with color filter 9. Application example to mobile body 1
10. Application example to endoscopic surgery system

1. 1. Introduction As described above, in the solid-state image sensor, it is desired to improve the photoelectric conversion efficiency of the photoelectric conversion element that converts incident light into electric charges in order to improve the image quality, distance measurement accuracy, and the like.

For example, in a camera or the like using a solid-state image sensor, when light is reflected on the light receiving surface of a photoelectric conversion element such as a photodiode and is incident on the photoelectric conversion element of another pixel, stray light (ghost flare) is generated. There is a problem that the image quality deteriorates.

The reason why the reflected light is generated when the photodiode is used as the photoelectric conversion element is that the refractive index changes significantly on the upper surface of the photodiode (the upper surface with respect to the incident light, which corresponds to the light receiving surface). For example, when a silicon substrate is used for the P layer and the N layer of the photodiode and the upper surface of the photodiode is covered with a silicon oxide film, the refractive index of silicon is as high as 3.8 to 5.6 in the visible light region. In contrast, the silicon oxide film is about 1.46, which is much smaller than that of silicon. Therefore, the reflectance at the interface between the silicon substrate and the silicon oxide film becomes 20% or more, and a large amount of light is reflected on the upper surface of the photodiode. This causes deterioration of image quality due to the generation of stray light and deterioration of image quality, distance measurement accuracy, etc. due to deterioration of photoelectric conversion efficiency.

Therefore, in the present embodiment, it is possible to reduce the reflected light from the upper surface of the photoelectric conversion element such as a photodiode. If the light reflected from the upper surface of the photoelectric conversion element can be reduced, the stray light can be suppressed and the ratio of the light incident on the photodiode can be increased, so that the photoelectric conversion efficiency can be improved.

However, even if the amount of light taken into the photodiode is increased, there is a problem that sufficient light cannot be absorbed because it is difficult to make the photodiode thick, and the sensitivity becomes insufficient.

In order to improve the light absorption rate in the photodiode, it is effective to increase the optical path length in the photodiode. Here, as a method of increasing the optical path length, a method of reflecting or refracting incident light by forming pyramid-shaped irregularities on the upper surface of the photodiode can be considered. According to such a structure, the light is obliquely incident in the photodiode and reflected by the element structure, so that the optical path length can be increased as compared with the case where the light is vertically incident.

However, since the reflected light from the pyramid-shaped unevenness exists, there is a problem that stray light is generated.

As a method of reducing the reflected light from the upper surface of the photodiode, there is a method of forming a fine protrusion, a so-called moth-eye structure, on the upper surface of the photodiode. However, in the structure in which the upper surface of the photodiode has a moth-eye structure, although the reflection from the upper surface of the photodiode can be reduced, the light is vertically incident into the photodiode without being diffracted, so that the light absorption rate is increased. The problem remains that it cannot be improved and the sensitivity becomes insufficient.

Therefore, in the following embodiment, the light reflected on the upper surface of the photodiode is suppressed to increase the amount of light taken into the photodiode, and the optical path length in the photodiode is lengthened to increase the amount of light absorbed. An example of a solid-state image sensor and an electronic device capable of improving the photoelectric conversion efficiency by increasing the number will be described.

2. First Embodiment First, the solid-state image sensor and the electronic device according to the first embodiment will be described in detail with reference to the drawings. In the present embodiment, the case where the technique according to the present embodiment is applied to the CMOS image sensor is illustrated, but the present invention is not limited to this, and various types including a photoelectric conversion element such as a ToF sensor using a SPAD pixel are provided. It is possible to apply the technique according to this embodiment to the sensor.

2.1 Configuration Example of Electronic Device FIG. 1 is a block diagram showing a schematic configuration example of an electronic device equipped with the solid-state image sensor according to the first embodiment. As shown in FIG. 1, the electronic device 1 includes, for example, an image pickup lens 10, a solid-state image pickup device 100, a storage unit 30, and a processor 20.

The image pickup lens 10 is an example of an optical system that collects incident light and forms an image on the light receiving surface of the solid-state image pickup device 100. The light receiving surface may be a surface on which the photoelectric conversion elements in the solid-state image sensor 100 are arranged. The solid-state image sensor 100 generates image data by photoelectrically converting the incident light. Further, the solid-state image sensor 100 executes predetermined signal processing such as noise removal and white balance adjustment on the generated image data.

The storage unit 30 is composed of, for example, a flash memory, a DRAM (Dynamic Random Access Memory), a SRAM (Static Random Access Memory), or the like, and records image data or the like input from the solid-state imaging device 100.

The processor 20 may include, for example, an application processor configured by using a CPU (Central Processing Unit) or the like and executing an operating system, various application software, or the like, a GPU (Graphics Processing Unit), a baseband processor, or the like. The processor 20 executes various processes as necessary for the image data input from the solid-state image sensor 100, the image data read from the storage unit 30, and the like, executes display to the user, and performs a predetermined network. It is sent to the outside via.

2.2 Configuration Example of Solid-State Image Sensor FIG. 2 is a block diagram showing a schematic configuration example of a CMOS-type solid-state image sensor (simply referred to as a CMOS image sensor or an image sensor) according to the first embodiment. Here, the CMOS image sensor is an image sensor created by applying or partially using the CMOS process. For example, the image sensor 100 according to the present embodiment is composed of a back-illuminated image sensor.

The image sensor 100 according to the present embodiment has, for example, a stack structure in which a semiconductor chip on which a pixel array portion 101 is formed and a semiconductor chip on which peripheral circuits are formed are laminated. Peripheral circuits may include, for example, a vertical drive circuit 102, a column processing circuit 103, a horizontal drive circuit 104, and a system control unit 105.

The image sensor 100 further includes a signal processing unit 108 and a data storage unit 109. The signal processing unit 108 and the data storage unit 109 may be provided on the same semiconductor chip as the peripheral circuit, or may be provided on another semiconductor chip.

In the pixel array unit 101, unit pixels (hereinafter, may be simply referred to as “pixels”) 110 having a photoelectric conversion element that generates and stores electric charges according to the amount of received light are arranged in the row direction and the column direction, that is, , It has a structure arranged in a two-dimensional grid pattern in a matrix. Here, the row direction means the arrangement direction of the pixels in the pixel row (in the drawing, the horizontal direction), and the column direction means the arrangement direction of the pixels in the pixel row (in the drawing, the vertical direction). The specific circuit configuration of the unit pixel and the details of the pixel structure will be described later.

In the pixel array unit 101, the pixel drive line LD is wired along the row direction for each pixel row and the vertical signal line VSL is wired along the column direction for each pixel row with respect to the matrix-shaped pixel array. The pixel drive line LD transmits a drive signal for driving when reading a signal from the pixel. In FIG. 2, the pixel drive lines LD are shown as wiring one by one, but the wiring is not limited to one by one. One end of the pixel drive line LD is connected to the output end corresponding to each line of the vertical drive circuit 102.

The vertical drive circuit 102 is composed of a shift register, an address decoder, and the like, and drives each pixel of the pixel array unit 101 simultaneously or in units of rows. That is, the vertical drive circuit 102 constitutes a drive unit that controls the operation of each pixel of the pixel array unit 101 together with the system control unit 105 that controls the vertical drive circuit 102. Although the specific configuration of the vertical drive circuit 102 is not shown, it generally includes two scanning systems, a read scanning system and a sweep scanning system.

The read-out scanning system selectively scans the unit pixels of the pixel array unit 101 row by row in order to read a signal from the unit pixels. The signal read from the unit pixel is an analog signal. The sweep-out scanning system performs sweep-out scanning for the read-out line on which read-out scanning is performed by the read-out scanning system, ahead of the read-out scan by the exposure time.

By the sweep scanning by this sweep scanning system, the photoelectric conversion element is reset by sweeping out unnecessary charges from the photoelectric conversion element of the unit pixel of the read row. Then, by sweeping out (resetting) unnecessary charges with this sweep-out scanning system, a so-called electronic shutter operation is performed. Here, the electronic shutter operation refers to an operation of discarding the electric charge of the photoelectric conversion element and starting a new exposure (starting the accumulation of electric charge).

The signal read by the read operation by the read scanning system corresponds to the amount of light received after the read operation or the electronic shutter operation immediately before that. Then, the period from the read timing by the immediately preceding read operation or the sweep timing by the electronic shutter operation to the read timing by the current read operation is the charge accumulation period (also referred to as the exposure period) in the unit pixel.

The signal output from each unit pixel of the pixel row selectively scanned by the vertical drive circuit 102 is input to the column processing circuit 103 through each of the vertical signal lines VSL for each pixel column. The column processing circuit 103 performs predetermined signal processing on the signal output from each pixel of the selected row through the vertical signal line VSL for each pixel column of the pixel array unit 101, and temporarily processes the pixel signal after the signal processing. Hold the target.

Specifically, the column processing circuit 103 performs at least noise removal processing, for example, CDS (Correlated Double Sampling) processing and DDS (Double Data Sampling) processing as signal processing. For example, the CDS process removes pixel-specific fixed pattern noise such as reset noise and threshold variation of the amplification transistor in the pixel. The column processing circuit 103 also has, for example, an AD (analog-digital) conversion function, and converts an analog pixel signal read from a photoelectric conversion element into a digital signal and outputs the signal.

The horizontal drive circuit 104 is composed of a shift register, an address decoder, and the like, and sequentially selects a read circuit (hereinafter, referred to as a pixel circuit) corresponding to the pixel sequence of the column processing circuit 103. By the selective scanning by the horizontal drive circuit 104, the pixel signals that have been signal-processed for each pixel circuit in the column processing circuit 103 are sequentially output.

The system control unit 105 is configured by a timing generator or the like that generates various timing signals, and based on the various timings generated by the timing generator, the vertical drive circuit 102, the column processing circuit 103, and the horizontal drive circuit 104. Drive control such as.

The signal processing unit 108 has at least an arithmetic processing function, and performs various signal processing such as arithmetic processing on the pixel signal output from the column processing circuit 103. The data storage unit 109 temporarily stores the data required for the signal processing in the signal processing unit 108.

The image data output from the signal processing unit 108 may be, for example, executed by a processor 20 or the like in the electronic device 1 equipped with the image sensor 100, or transmitted to the outside via a predetermined network. You may.

2.3 Configuration example of a unit pixel FIG. 3 is a circuit diagram showing a schematic configuration example of a unit pixel according to the present embodiment. As shown in FIG. 3, the unit pixel 110 includes a photodiode PD, a transfer transistor 111, a reset transistor 112, an amplification transistor 113, a selection transistor 114, and a floating diffusion layer FD.

The selection transistor drive line LD 114 included in the pixel drive line LD is connected to the gate of the selection transistor 114, and the reset transistor drive line LD 112 included in the pixel drive line LD is connected to the gate of the reset transistor 112. The transfer transistor drive line LD111 included in the pixel drive line LD is connected to the gate of 111. Further, a vertical signal line VSL having one end connected to the column processing circuit 103 is connected to the drain of the amplification transistor 113 via the selection transistor 114.

In the following description, the reset transistor 112, the amplification transistor 113, and the selection transistor 114 are also collectively referred to as a pixel circuit. The pixel circuit may include a floating diffusion layer FD and / or a transfer transistor 111.

The photodiode PD photoelectrically converts the incident light. The transfer transistor 111 transfers the electric charge generated in the photodiode PD. The floating diffusion layer FD accumulates the electric charge transferred by the transfer transistor 111. The amplification transistor 113 causes a pixel signal having a voltage value corresponding to the electric charge accumulated in the floating diffusion layer FD to appear on the vertical signal line VSL. The reset transistor 112 releases the electric charge accumulated in the floating diffusion layer FD. The selection transistor 114 selects the unit pixel 110 to be read.

The anode of the photodiode PD is grounded and the cascade is connected to the source of the transfer transistor 111. The drain of the transfer transistor 111 is connected to the source of the reset transistor 112 and the gate of the amplification transistor 113, and the nodes at these connection points form the floating diffusion layer FD. The drain of the reset transistor 112 is connected to a vertical reset input line (not shown).

The source of the amplification transistor 113 is connected to a vertical current supply line (not shown). The drain of the amplification transistor 113 is connected to the source of the selection transistor 114, and the drain of the selection transistor 114 is connected to the vertical signal line VSL.

The floating diffusion layer FD converts the accumulated electric charge into a voltage having a voltage value corresponding to the amount of the electric charge. The floating diffusion layer FD may have, for example, a grounding capacitance. However, the present invention is not limited to this, and the floating diffusion layer FD is added by intentionally connecting a capacitor or the like to a node to which the drain of the transfer transistor 111, the source of the reset transistor 112, and the gate of the amplification transistor 113 are connected. It may be a capacity.

2.4 Example of Basic Function of Unit Pixel Next, the basic function of the unit pixel 110 will be described with reference to FIG. The reset transistor 112 controls the discharge (reset) of the electric charge stored in the floating diffusion layer FD according to the reset signal RST supplied from the vertical drive circuit 102 via the reset transistor drive line LD112. By turning on the transfer transistor 111 when the reset transistor 112 is on, in addition to the electric charge accumulated in the floating diffusion layer FD, the electric charge accumulated in the photodiode PD is discharged (reset). It is also possible to do.

When a high level reset signal RST is input to the gate of the reset transistor 112, the floating diffusion layer FD is clamped to the voltage applied through the vertical reset input line. As a result, the electric charge accumulated in the floating diffusion layer FD is discharged (reset).

Further, when the Low level reset signal RST is input to the gate of the reset transistor 112, the floating diffusion layer FD is electrically disconnected from the vertical reset input line and becomes a floating state.

The photodiode PD photoelectrically converts the incident light and generates an electric charge according to the amount of the light. The generated charge is accumulated on the cathode side of the photodiode PD. The transfer transistor 111 controls the transfer of electric charges from the photodiode PD to the floating diffusion layer FD according to the transfer control signal TRG supplied from the vertical drive circuit 102 via the transfer transistor drive line LD111.

For example, when a high-level transfer control signal TRG is input to the gate of the transfer transistor 111, the charge stored in the photodiode PD is transferred to the floating diffusion layer FD. On the other hand, when the low level transfer control signal TRG is supplied to the gate of the transfer transistor 111, the transfer of electric charge from the photodiode PD is stopped.

As described above, the floating diffusion layer FD has a function of converting the electric charge transferred from the photodiode PD via the transfer transistor 111 into a voltage having a voltage value corresponding to the amount of the electric charge. Therefore, in the floating state in which the reset transistor 112 is turned off, the potential of the floating diffusion layer FD is modulated according to the amount of electric charge accumulated by each.

The amplification transistor 113 functions as an amplifier that uses the potential fluctuation of the floating diffusion layer FD connected to the gate as an input signal, and the output voltage signal appears as a pixel signal on the vertical signal line VSL via the selection transistor 114.

The selection transistor 114 controls the appearance of the pixel signal by the amplification transistor 113 on the vertical signal line VSL according to the selection control signal SEL supplied from the vertical drive circuit 102 via the selection transistor drive line LD 114. For example, when a high-level selection control signal SEL is input to the gate of the selection transistor 114, a pixel signal from the amplification transistor 113 appears on the vertical signal line VSL. On the other hand, when the Low level selection control signal SEL is input to the gate of the selection transistor 114, the appearance of the pixel signal on the vertical signal line VSL is stopped. As a result, in the vertical signal line VSL in which a plurality of unit pixels 110 are connected, it is possible to extract only the output of the selected unit pixel 110.

2.5 Example of laminated structure of solid-state image sensor FIG. 4 is a diagram showing an example of a laminated structure of an image sensor according to the present embodiment. As shown in FIG. 4, the image sensor 100 has a structure in which a light receiving chip 121 and a circuit chip 122 are vertically laminated. The light receiving chip 121 is, for example, a semiconductor chip including a pixel array unit 101 in which the photodiode PD is arranged, and the circuit chip 122 is, for example, a semiconductor chip in which the pixel circuits shown in FIG. 3 are arranged.

For joining the light receiving chip 121 and the circuit chip 122, for example, so-called direct bonding, in which the respective bonding surfaces are flattened and the two are bonded by intermolecular force, can be used. However, the present invention is not limited to this, and for example, so-called Cu-Cu bonding in which copper (Cu) electrode pads formed on the bonding surfaces of each other are bonded to each other, or other bump bonding or the like can be used. ..

Further, the light receiving chip 121 and the circuit chip 122 are electrically connected via, for example, a connecting portion such as a TSV (Through-Silicon Via) penetrating the semiconductor substrate. Connections using TSVs include, for example, a so-called twin TSV method in which two TSVs, a TSV provided on the light receiving chip 121 and a TSV provided from the light receiving chip 121 to the circuit chip 122, are connected on the outer surface of the chip, or a light receiving method. A so-called shared TSV method or the like in which both are connected by a TSV penetrating from the chip 121 to the circuit chip 122 can be adopted.

However, when Cu-Cu bonding or bump bonding is used for bonding the light receiving chip 121 and the circuit chip 122, both are electrically connected via the Cu-Cu bonding portion or the bump bonding portion.

2.6 Example of cross-sectional structure of a unit pixel Next, an example of a cross-sectional structure of the image sensor 100 according to the first embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view showing an example of a cross-sectional structure of the image sensor according to the first embodiment. Note that FIG. 5 shows an example of a cross-sectional structure of the light receiving chip 121 on which the photodiode PD in the pixel 110 is formed.

As shown in FIG. 5, in the image sensor 100, the photodiode PD receives the incident light L1 incident from the back surface (upper surface in the figure) side of the semiconductor substrate 138. A flattening film 133 and an on-chip lens 131 are provided above the photodiode PD, and incident light L1 incident through each portion is received by the light receiving surface 137 to perform photoelectric conversion.

For example, in the photodiode PD, the N-type semiconductor region 139 is formed as a charge storage region for accumulating charges (electrons). In the photodiode PD, the N-type semiconductor region 139 is provided in the region surrounded by the P-type semiconductor regions 136 and 144 of the semiconductor substrate 138. On the front surface (lower surface) side of the semiconductor substrate 138 of the N-type semiconductor region 139, a P-type semiconductor region 144 having a higher impurity concentration than the back surface (upper surface) side is provided. That is, the photodiode PD has a HAD (Hole-Accumulation Diode) structure, and the P is suppressed so as to suppress the generation of dark current at each interface between the upper surface side and the lower surface side of the N-type semiconductor region 139. Type semiconductor regions 136 and 144 are formed.

Inside the semiconductor substrate 138, a pixel separation unit 140 that electrically separates a plurality of pixels 110 is provided, and a photodiode PD is provided in a region partitioned by the pixel separation unit 140. .. When the image sensor 100 is viewed from the upper surface side in the figure, the pixel separation unit 140 is formed in a grid pattern so as to intervene between a plurality of pixels 110, for example, and the photodiode PD has the pixel separation. It is formed in the area partitioned by the part 140.

In each photodiode PD, the anode is grounded, and in the image sensor 100, the signal charges (for example, electrons) accumulated in the photodiode PD are read out via a transfer transistor 111 (see FIG. 3) (see FIG. 3) which is not shown. Then, it is output as an electric signal to a vertical signal line 124 (see FIG. 3) (see FIG. 3) which is not shown.

The wiring layer 145 is provided on the front surface (lower surface) of the semiconductor substrate 138 opposite to the back surface (upper surface) where the light-shielding film 134, the on-chip lens 131, and the like are provided.

The wiring layer 145 includes a wiring 146 and an insulating layer 147, and is formed in the insulating layer 147 so that the wiring 146 is electrically connected to each element. The wiring layer 145 is a layer of so-called multi-layer wiring, and is formed by alternately laminating the interlayer insulating film constituting the insulating layer 147 and the wiring 146 a plurality of times. Here, as the wiring 146, wiring to a transistor for reading charge from a photodiode PD such as a transfer transistor 111 and wiring such as a vertical signal line 124 are laminated via an insulating layer 147.

For example, the circuit chip 122 illustrated in FIG. 4 is bonded to the surface of the wiring layer 145 opposite to the side on which the photodiode PD is provided.

The light-shielding film 134 is provided on the back surface side (upper surface in the drawing) of the semiconductor substrate 138.

The light-shielding film 134 is configured to block a part of the incident light L1 from above the semiconductor substrate 138 toward the back surface of the semiconductor substrate 138.

The light-shielding film 134 is provided above the pixel separation portion 140 provided inside the semiconductor substrate 138. Here, the light-shielding film 134 is provided on the back surface (upper surface) of the semiconductor substrate 138 so as to project in a convex shape via an insulating film 135 such as a silicon oxide film. On the other hand, above the photodiode PD provided inside the semiconductor substrate 138, the light-shielding film 134 is not provided and is open so that the incident light L1 is incident on the photodiode PD. ..

That is, when the image sensor 100 is viewed from the upper surface side in the drawing, the planar shape of the light-shielding film 134 is a grid pattern, and an opening through which the incident light L1 passes to the light receiving surface 137 is formed.

The light-shielding film 134 is formed of a light-shielding material that blocks light. For example, the light-shielding film 134 is formed by sequentially laminating a titanium (Ti) film and a tungsten (W) film. In addition to this, the light-shielding film 134 can be formed, for example, by sequentially laminating a titanium nitride (TiN) film and a tungsten (W) film.

The light-shielding film 134 is covered with the flattening film 133. The flattening film 133 is formed by using an insulating material that transmits light. For this insulating material, for example, silicon oxide (SiO ₂ ) or the like can be used.

The pixel separation unit 140 has, for example, a groove portion 141, a fixed charge film 142, and an insulating film 143.

The fixed charge film 142 is formed on the back surface (upper surface) side of the semiconductor substrate 138 so as to cover the groove 141 partitioning between the plurality of pixels 110.

Specifically, the fixed charge film 142 is provided so as to cover the inner surface of the groove portion 141 formed on the back surface (upper surface) side of the semiconductor substrate 138 with a constant thickness. Then, an insulating film 143 is provided (filled) so as to embed the inside of the groove portion 141 covered with the fixed charge film 142.

Here, the fixed charge film 142 uses a high dielectric having a negative fixed charge so that a positive charge (hole) storage region is formed at the interface with the semiconductor substrate 138 and the generation of dark current is suppressed. Is formed. Since the fixed charge film 142 is formed so as to have a negative fixed charge, an electric field is applied to the interface with the semiconductor substrate 138 due to the negative fixed charge, and a positive charge (hole) storage region is formed.

The fixed charge film 142 can be formed of, for example, a hafnium oxide film (HfO _{2 film).} In addition, the fixed charge film 142 can be formed so as to contain at least one of other oxides such as hafnium, zirconium, aluminum, tantalum, titanium, magnesium, yttrium, and lanthanoid elements.

The pixel separation unit 140 is not limited to the above configuration and can be variously modified. For example, by using a light-reflecting reflective film such as a tungsten (W) film instead of the insulating film 143, the pixel separation unit 140 can have a light-reflecting structure. As a result, the incident light L1 that has entered the photodiode PD can be reflected by the pixel separation unit 140, so that the optical path length of the incident light L1 in the photodiode PD can be lengthened. In addition, by forming the pixel separation unit 140 with a light reflection structure, it is possible to reduce leakage of light to adjacent pixels, so that it is possible to further improve image quality, distance measurement accuracy, and the like. When a metal material such as tungsten (W) is used as the material of the reflective film, an insulating film such as a silicon oxide film may be provided in the groove 141 instead of the fixed charge film 142.

Further, the configuration in which the pixel separation portion 140 has a light reflection structure is not limited to the configuration using a reflective film, and can be realized by, for example, embedding a material having a refractive index higher or lower than that of the semiconductor substrate 138 in the groove portion 141. can do.

Further, FIG. 5 illustrates a pixel separation portion 140 having a so-called RDTI (Reverse Deep Trench Isolation) structure in which the pixel separation portion 140 is provided in the groove portion 141 formed from the back surface (upper surface) side of the semiconductor substrate 138. However, the present invention is not limited to this, for example, a so-called DTI (Deep Trench Isolation) structure in which the pixel separation portion 140 is provided in the groove portion formed from the surface (lower surface) side of the semiconductor substrate 138, or the semiconductor substrate 138. It is possible to adopt a pixel separation portion 140 having various structures such as a so-called FTI (Full Trench Isolation) structure in which a pixel separation portion 140 is provided in a groove portion formed so as to penetrate the front and back surfaces of the above.

Further, in the present embodiment, as shown in FIG. 5, the incident light L1 is diffracted on the light receiving surface 137 of the photodiode PD at the interface between the semiconductor substrate 138 and the insulating film 135 while suppressing the reflection of the incident light L1. A concave-convex structure 150 for making the structure 150 is provided. The uneven structure 150 will be described in detail below.

2.7 Concavo-convex structure FIG. 6 is a cross-sectional view showing a concavo-convex structure formed on the light receiving surface of the photodiode in the present embodiment. In FIG. 6 and the following description, for simplification, the semiconductor substrate 138 on which the photodiode PD is formed and the insulating film 135 formed on the semiconductor substrate 138 are extracted. Further, in this description, for the sake of clarification, the incident side of the incident light L1 is set to the upper side.

As shown in FIG. 6, in the present embodiment, the concave-convex structure 150 is formed on the light receiving surface 137 of the photodiode PD. The light receiving surface 137 may be, for example, a flat surface that is the uppermost surface of the semiconductor substrate 138 and includes the upper surface of the upper convex portion 152a in the concave-convex structure 150. However, the present invention is not limited to this, and the flat surface including the bottom surface of the groove formed by the downward convex portion 151a in the concave-convex structure 150 and the flat surface including the upper surface of the upper convex portion 152a and the bottom surface of the groove formed by the downward convex portion 151a. Various changes can be made, such as the area between the containing planes.

The concave-convex structure 150 has a function of reducing reflection of incident light L1 incident on the photodiode PD and increasing the ratio of transmitted diffraction in the photodiode PD. In order to realize these two functions, the concave-convex structure 150 is configured to satisfy the following equations (1) and (2).

In the formulas (1) and (2), n _p is the refractive index of the material forming the photodiode PD, that is, the semiconductor substrate 138, and n _U is the film formed on the photodiode PD, that is, the insulating film 135. Refractive index. Further, P is the pitch of the concave-convex structure 150, and λ ₀ is the wavelength of the incident light L1 in vacuum. The refractive indexes n _p and n _U are values for this wavelength.

Equation (1) shows that the refractive index n _{U of the insulating film 135 is smaller than the refractive index n p} of the semiconductor substrate 138 forming the photodiode PD. Further, the equation (2) shows the pitch condition of the concave-convex structure 150. The equation (1) is a condition necessary to satisfy the condition of the equation (2).

The wavelength of the incident light L1 in the insulating film 135 is λ ₀ / n _U , and the wavelength of the incident light L1 in the photodiode PD is λ ₀ / n _P. Therefore, the wavelength of the incident light L1 in the photodiode PD is shorter than the wavelength of the incident light L1 in the insulating film 135.

Further, the left side of the equation (2) is a condition necessary for the incident light L1 passing through the concave-convex structure 150 to be diffracted in the photodiode PD. The left and right sides of the formula (2) are conditions necessary for not generating reflected diffracted light from the concave-convex structure 150 upward. By satisfying such a condition, it is possible to ignore non-diffraction light (reflected light similar to that in the case of a flat surface) L2 for reflection to the upper side, which facilitates the design of the concave-convex structure 150. be able to.

Further, the dimensions of the concave-convex structure 150 are designed to increase the rate at which the incident light L1 is transmitted and diffracted in the photodiode PD. That is, the concave-convex structure 150 functions as a diffraction grating in which the intensity of the non-diffraction light L10 is reduced when viewed from the photodiode PD side.

However, when the concave-convex structure 150 is designed so that the non-diffraction light L10 toward the photodiode PD side becomes small, reflection occurs on the upper side, that is, on the insulating film 135 side. Therefore, in the present embodiment, in order to suppress reflection to the insulating film 135 side, the concave-convex structure 150 is divided into a first layer 151 made of a downward convex portion 151a and a second layer 152 made of an upper convex portion 152a. There is.

The diffracted light L11 transmitted and diffracted in the photodiode PD is confined in the photodiode PD by a high reflectance pixel separation unit 140 (not shown in FIG. 6) provided between the adjacent photodiode PDs. reflect.

Subsequently, the respective structures of the first layer 151 and the second layer 152 in the concave-convex structure 150 will be described below. Since the light incident on the photodiode PD (incident light L1) is dominated by the component perpendicular to the light receiving surface 137, the case of optimizing for the vertically incident light will be described below.

2.7.1 Structural example of the first layer First, a structural example of the first layer 151 will be described. The first layer 151 includes, for example, a structure of a diffraction grating. Therefore, the first layer 151 is designed so that its dimensions approach the following equations (3) and (4) so that a large amount of non-diffraction light L10 is not generated on the photodiode PD side.

In the formula (3), the convex portion is the downward convex portion 151a, and the upper surface thereof is the upper surface of the downward convex portion 151a. Further, the concave portion is a groove between adjacent downward convex portions 151a, and the bottom surface thereof is the bottom surface of the groove.

The equation (4) expressing the height means that the phase difference between the light passing through the convex portion and the light passing through the concave portion is half a cycle. By satisfying the condition of the equation (4), the light passing through the convex portion and the light passing through the concave portion cancel each other out. As a result, ideally, the intensity of the non-diffraction light L10 becomes zero.

The upper surface layout of the downward convex portion 151a in the first layer 151 formed on the upper portion of the semiconductor substrate 138 is not limited to a specific shape. For example, as shown in FIG. 7, it may be a stripe-shaped repeating pattern, or as shown in FIG. 8, it may be a dot-shaped repeating pattern.

Further, FIG. 6 illustrates a case where the side wall of the downward convex portion 151a is perpendicular to the light receiving surface 137, but the present invention is not limited to this. For example, the side wall of the downward convex portion 151a may be inclined with respect to the light receiving surface 137. Also in this case, the layout and height of the upper surface and the lower surface of the lower convex portion 151a in the first layer 151 are designed so that the intensity of the non-diffraction light L10 becomes smaller.

The layout dimension of the downward convex portion 151a may be optimized by using, for example, the FDTD method (Finite-Difference Time-Domain Method), which is a kind of electromagnetic field calculation method.

2.7.2 Structural example of the second layer Next, a structural example of the second layer 152 will be described. The size and height of the upper convex portion 152a constituting the second layer 152 are designed so that, for example, the intensity of the reflected light L2 upward is reduced.

_{Here, assuming} that the effective refractive index of the first layer 151 is n eff11, the second layer 152 is _{designed so that its effective refractive index n eff12} is a value close to the equation (5).

In order to bring the effective refractive index n _{eff 12} of the second layer 152 closer to the equation (7), the height H ₁₂ of the upper convex portion 152a is designed to have a value close to the following equation (6).

Equations (5) and (6) are conditions for canceling the reflected light on the upper surface of the second layer 152 and the reflected light on the lower surface of the second layer 152.

Here, the effective refractive index of the layer which is a mixture of a certain medium 1 and a different medium 2 can be obtained from, for example, the Lorentz-Lorenz equation shown in the following equation (7).

_{Therefore, if the effective refractive index n eff12} desired for the second layer 152 is obtained by the equation (5), the volume ratio of the convex portion to the concave portion in the second layer 152, that is, the upper convex portion 152a is formed from the equation (7). The volume ratio between the formed region and the region where the upper convex portion 152a is not formed can be obtained. Thereby, the dimension of the upper surface of the upper convex portion 152a can be obtained.

The size of the upper convex portion 152a for reducing the reflected light L2 upward may be determined by using, for example, the FDTD method or the like.

Further, the layout of the upper convex portion 152a in the second layer 152a is not limited to a specific shape. Further, the side wall of the upper convex portion 152a does not have to be perpendicular to the light receiving surface 137.

For example, a striped upper convex portion 152a as illustrated in FIG. 9 may be formed on the upper surface of the striped lower convex portion 151a illustrated in FIG. 7, or a striped upper convex portion 152a as illustrated in FIG. 10 may be formed. A rectangular dot-shaped upper convex portion 152a may be formed, or a striped upper convex portion 152a having a length similar to the width of the lower convex portion 151a as illustrated in FIG. 11 may be formed. Good.

In the examples shown in FIGS. 9 to 11, the distance between the adjacent upper convex portions 152a does not have to be uniform as long as it is smaller than _{λ 0} / 2n _U.

Further, a rectangular dot-shaped upper convex portion 152a as illustrated in FIG. 12 may be formed on the upper surface of the dot-shaped lower convex portion 151a illustrated in FIG. 8, as illustrated in FIG. The upper convex portion 152a having a round dot shape may be formed.

Further, as illustrated in FIG. 14, the upper convex portion 152a may be a frustum having a flat upper surface and an inclined side surface, a frustum having a sharp upper surface, or the like.

Furthermore, the second layer 152 may be further divided into a plurality of layers. For example, as illustrated in FIG. 15, the second layer 152 may be composed of a lower layer 1521 composed of a first upper convex portion 1521a and an upper layer 1522 composed of a second upper convex portion 1522a. In this way, when the second layer 152 is further made into multiple layers, it is possible to obtain the same effect as the multi-layered antireflection film, so that the reflection thereof can be sufficiently reduced even for light having a wide band wavelength. Is possible.

2.8 Actions / Effects As described above, according to the present embodiment, the concave-convex structure 150 aims at the first layer 151 for the purpose of transmission diffraction to the photodiode PD and for the purpose of reducing reflection upward. It has a multi-layer structure with the second layer 152. As a result, it is possible to reduce the reflection of the incident light L1 on the upper surface of the photodiode PD, so that the reflected light L2 is less likely to be reflected on other pixels as stray light (ghost flare), and as a result, the image quality is improved. It is possible to suppress the decrease. In addition, since it is possible to increase the proportion of light absorbed in the photodiode PD, it is possible to improve the photoelectric conversion efficiency and increase the sensitivity. Further, since the photoelectric conversion efficiency is improved, the thickness of the semiconductor substrate 138 corresponding to the depth direction of the photodiode PD can be reduced, so that the solid-state image sensor 100 can be downsized and manufactured easily. It is also possible to achieve reduction of manufacturing cost and the like.

3. 3. Second Embodiment Next, the solid-state image sensor and the electronic device according to the second embodiment will be described in detail with reference to the drawings. In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description thereof will be omitted.

In the present embodiment, the schematic configuration example of the solid-state image sensor and the electronic device may be the same as that described in the first embodiment. However, in the present embodiment, the concave-convex structure 150 is replaced with the one illustrated below.

3.1 Concavo-convex structure FIG. 16 is a cross-sectional view showing a concavo-convex structure formed on the light receiving surface of the photodiode in the present embodiment. In FIG. 16 and the following description, for simplification, the semiconductor substrate 138 on which the photodiode PD is formed and the insulating film 135 formed on the semiconductor substrate 138 are extracted. Further, in this description, for the sake of clarification, the incident side of the incident light L1 is set to the upper side.

Further, in the following description, as described in the first embodiment, the light incident on the photodiode PD (incident light L1) is dominated by the component perpendicular to the light receiving surface 137. A structure optimized for vertically incident light will be described.

As shown in FIG. 16, the concavo-convex structure 250 according to the present embodiment includes a first layer 251 composed of a plurality of convex portions 251a and a second layer 252 that covers the convex portions 251a and has a flat upper surface. The second layer 252 may be, for example, a film having a refractive index n _M is composed of a different material than the protruding portion 251a.

3.1.1 Structural Example of First Layer The convex portion 251a in the first layer 251 may be, for example, the same as the lower convex portion 151a of the first layer 151 illustrated in the first embodiment. However, in the concave-convex structure 250, the space between the convex portions 251a in the first layer 251 is filled with the second layer 252. Therefore, dimensions such as the pitch and height of the convex portion 251a are set as follows.

_{The refractive index n M} of the second layer 252 is set to a value between the refractive index n _{p of the} photodiode PD and the refractive index n _{U of the insulating film 135.} Therefore, in order to reduce the reflection of the incident light L1 incident on the photodiode PD and increase the ratio of transmitted diffraction in the photodiode PD, the pitch P of the convex portion 251a constituting the first layer 251 is increased. Needs to be designed to satisfy the condition shown in the following equation (8).

On the other hand, in order to suppress the non-diffraction light L10 transmitted to the photodiode PD side, the dimensions of the convex portion 251a of the first layer 251 should approach the following equations (9) and (10). Designed.

In the formula (10), the convex portion is the convex portion 251a, and the upper surface thereof is the upper surface of the convex portion 251a. Further, the concave portion is a groove between adjacent convex portions 251a, and the bottom surface thereof is the bottom surface of the groove.

The equation (10) expressing the height means that the phase difference between the light passing through the convex portion and the light passing through the concave portion is half a cycle, as in the case of the first layer 151 in the first embodiment. By satisfying the condition of the equation (10), the light passing through the convex portion and the light passing through the concave portion cancel each other out. As a result, ideally, the intensity of the non-diffraction light L10 becomes zero.

Similar to the downward convex portion 151a in the first embodiment, the upper surface layout of the convex portion 251a is not limited to a specific shape. Further, the side wall of the convex portion 251a may be perpendicular to or inclined with respect to the light receiving surface 137, similarly to the downward convex portion 151a. Also in this case, the layout and height of the upper surface and the lower surface of the convex portion 251a in the first layer 251 are designed so that the intensity of the non-diffraction light L10 becomes smaller. Further, the layout dimensions of the convex portion 251a may be optimized by using, for example, the FDTD method.

3.1.2 Structural example of the second layer Next, a structural example of the second layer 252 will be described. The second layer 252 is formed, for example, by using an insulating material having a refractive index different from that of the convex portion 251a of the first layer 251. As the insulating material, for example, oxides such as hafnium, zirconium, aluminum, tantalum, titanium, magnesium, yttrium, and lanthanoid elements can be used. However, the present invention is not limited to this, and various materials may be used as long as they are insulating materials having a refractive index different from that of the convex portion 251a.

The refractive index n _M and the height H _M of the second layer 252 are designed such that the reflected intensity in the upper is reduced. _{Here, assuming} that the effective refractive index of the first layer 251 is n eff21, the refractive index n _M of the second layer 252 is designed to have a value close to the following equation (11). The refractive index n _M of the second layer 252 can be adjusted by controlling, for example, the material composition, the film forming conditions, and the like.

The height H _M of the second layer _252, that is, the thickness from the upper surface of the convex portion 251a to the upper surface of the second layer 252 is designed to be a value close to the following equation (12).

Equations (11) and (12) are conditions for the reflected light from the upper surface and the reflected light from the lower surface of the second layer 252 to cancel each other out.

As illustrated in FIG. 17, the second layer 252 may have a multi-layer structure including the lower layer 252a and the upper layer 252b. At that time, as illustrated in FIG. 18, one or more layers including the lower layer 252a may be conformally formed on the convex portion 251a of the first layer 251.

When the second layer 252 has a multi-layer structure, the calculation for obtaining the height of each layer becomes complicated and it is necessary to determine it by using simulation or the like, but the principle of suppressing the reflection to the upper side is the case where it is a single layer. The same is true. That is, with respect to the second layer 252 formed in the concave portion between the convex portions 251a of the first layer 251, the phase difference between the light passing through the convex portion 251a of the first layer 251 and the light passing through the concave portion between them is large. By designing the height of each layer so as to have a half cycle, the non-diffraction light L10 in the photodiode PD can be reduced. Further, for the second layer 252 above the upper surface of the convex portion 251a, the height of each layer is designed so that the reflection to the upper side is minimized.

By forming the second layer 252 into a multi-layer structure, it is possible to increase the degree of freedom in selecting the material used for the second layer 252, and to sufficiently reduce the reflection of light having a wide band wavelength. It becomes possible to do.

3.2 Actions / Effects As described above, according to the first embodiment, the concave-convex structure 150 is the first layer 251 for the purpose of transmission diffraction to the photodiode PD. It has a multi-layer structure with a second layer 252 for the purpose of reducing reflection on the upper side. As a result, it is possible to reduce the reflection of the incident light L1 on the upper surface of the photodiode PD, so that it is possible to suppress deterioration of image quality due to stray light (ghost flare) and improve sensitivity by improving photoelectric conversion efficiency. It becomes.

Since other configurations, operations, and effects may be the same as those in the above-described embodiment, detailed description thereof will be omitted here.

4. About pupil correction In the above-described embodiment, the case where the component perpendicular to the light receiving surface 137 is dominant in the incident light L1 incident on the photodiode PD is illustrated, but it is inclined with respect to the normal of the light receiving surface 137. Even when the components to be formed are dominant, that is, when the image height, which is the distance from the optical center of the image pickup lens 10, is high, the dimensions of each layer can be designed by the same method.

For example, as illustrated in FIG. 19, assuming that the incident light L1 is incident at an angle θ with respect to the optical axis C, the wavelength component in the vertical direction can be obtained as _{λ 0 / cos θ.} Therefore, the dimensions of the first layer 151/251 and the second layer 152/252 in the concave-convex structure 150/250 can be obtained by using _{λ 0} / cos θ instead of the _{wavelength λ 0.} At that time, the dimensions may be optimized by using the FDTD method or the like.

Such correction according to the image height (pupil correction) is, for example, the inclination of the incident light L1 with respect to the optical axis of the main component, that is, the inclination of the incident light L1 with respect to the optical axis according to the increase of each unit pixel 110. It may be optimized accordingly.

5. Comparison Results Next, the effects of each of the above-described embodiments will be described based on comparison with comparative examples.

FIG. 20 is a side-by-side list of cross-sectional structure examples of the layer structure according to the comparative example and the layer structure according to the first and second embodiments. The layer structure may be, for example, a layer structure corresponding to the layer structure of the semiconductor substrate 138 on which the photodiode PD is formed in the above-described embodiment and the insulating film 135 on the semiconductor substrate 138. In this description, a case where the upper surface film 501 is used instead of the insulating film 135 will be illustrated. Further, in this description, for the sake of clarification, the incident side of the incident light is set to the upper side.

Further, in the simulation described below, it is assumed that a silicon substrate is used for the semiconductor substrate 138 and alumina (Al ₂ O ₃ ) is used for the upper surface film 501. Further, the wavelength of the incident light L1 is 700 nm, the refractive index n of the semiconductor substrate 138 is 3.722, the extinction coefficient k of the semiconductor substrate 138 is 0.011, and the refractive index n of the upper surface film 501 is 1.511. , The extinction coefficient k of the upper surface film 501 is set to 0.

In FIG. 20, (a) shows an example of a cross-sectional structure (this is referred to as Comparative Example 1) in the case where the interface between the semiconductor substrate 138 and the upper surface film 501 (corresponding to the light receiving surface 137) is flat without an uneven structure. , (B) is an example of a cross-sectional structure in the case where a fine concavo-convex structure (hereinafter, also referred to as a moth-eye structure) 520 for the purpose of reducing reflection is provided at the interface between the semiconductor substrate 138 and the upper surface film 501 (this is referred to as a cross-sectional structure). Comparative Example 2) is shown, and (c) shows the upper surface represented by the formulas (2) to 4) in the first embodiment having the pitch P and the dimensions at the interface between the semiconductor substrate 138 and the upper surface film 501. An example of a cross-sectional structure (this is referred to as Comparative Example 2) in the case where the concavo-convex structure 530 to be satisfied is provided, and (d) shows the concavo-convex structure according to the first embodiment at the interface between the semiconductor substrate 138 and the upper surface film 501. An example of a cross-sectional structure when 150 is provided is shown, and (e) shows an example of a cross-sectional structure when the concavo-convex structure 250 according to the second embodiment is provided at the interface between the semiconductor substrate 138 and the upper surface film 501. ing.

In Comparative Example 2 shown in (b), the uneven pitch of the moth-eye structure 520 is 100 nm, the height of the convex portion is 73 nm, and the area ratio between the upper surface of the convex portion and the bottom surface of the concave portion of the moth-eye structure 520 is 60. It was set to 3%.

In Comparative Example 3 shown in (c), the uneven pitch of the concave-convex structure 530 is 200 nm, the height of the convex portion is 155 nm, and the area ratio between the upper surface of the convex portion and the bottom surface of the concave portion in the concave-convex structure 530 is 1: 1. It was set to 1.

In the first embodiment shown in (d), the pitch of the lower convex portion 151a of the first layer 151 in the concave-convex structure 150 is 200 nm, the height of the lower convex portion 151a is 155 nm, and the upper surface of the lower convex portion 151a is set. The area ratio of the concave portion formed therein to the bottom surface is 1: 1, the pitch of the upper convex portion 152a of the second layer 152 is 200 nm, the height of the upper convex portion 152a is 96 nm, and the upper convex portion 152a is formed. The area ratio between the upper surface and the bottom surface of the recess formed by the upper surface was set to 26.1%.

In the second embodiment shown in (e), the pitch of the convex portion 251a of the first layer 251 in the concave-convex structure 250 is 200 nm, the height of the convex portion 251a is 179 nm, and the upper surface of the convex portion 251a and the convex portion 251a are formed. The area ratio of the concave portion to the bottom surface is 1: 1, the refractive index n of the second layer 252 is 1.817, the extinction coefficient k of the second layer 252 is 0, and the convex portion 251a is second from the upper surface. The height to the upper surface of the layer 252 was set to 96 nm. Further, for the second layer 252, SiON whose element ratio was adjusted so that the refractive index was 1.817 was used.

FIG. 21 shows the light in each cross section when the incident light is incident on the light receiving surface in the direction perpendicular to the light receiving surface (from top to bottom in the drawing) with respect to the cross-sectional structures shown in FIGS. 20 (a) to 20 (e). It is a figure which shows the result of having calculated the intensity by the FDTD method. 21 (a) corresponds to FIG. 20 (a), FIG. 21 (b) corresponds to FIG. 20 (b), and FIG. 21 (c) corresponds to FIG. 20 (c). , FIG. 21 (d) corresponds to FIG. 20 (d), and FIG. 21 (e) corresponds to FIG. 20 (e). The bar 500 shown in the drawing shows the correspondence between the light intensity and the hatching density in each cross-sectional view.

As shown in FIG. 21 (a), in Comparative Example 1, since the reflection to the upper side is large, the standing wave (interference fringes due to the incident light and the reflected light) in the upper surface film 501 is large. On the other hand, since the light intensity in the semiconductor substrate 138 is relatively low, it can be seen that not much light is incident in the semiconductor substrate 138.

As shown in (b), in Comparative Example 2, the reflection at the interface is reduced by the moth-eye structure 520, and thereby the standing wave in the upper surface film 501 is also reduced. However, since no interference fringes due to the diffracted light are observed in the semiconductor substrate 138, it can be seen that the diffracted light is not generated and the optical path length in the semiconductor substrate 138 is not extended.

As shown in (b), in Comparative Example 3, clear light and darkness (interference fringes) are periodically observed in the semiconductor substrate 138. It can be seen that the optical path length in the semiconductor substrate 138 is extended because the non-diffraction light is small and the interference fringes are formed by the interference of the ± 1st-order diffracted light. However, since the upward reflection is not suppressed, the standing wave in the upper surface film 501 is also large.

As shown in (d) and (e), in the first and second embodiments, interference fringes are observed in the semiconductor substrate 138 due to the ± 1st order diffracted light, so that the optical path length in the semiconductor substrate 138 is increased. You can see that it is extended. In addition, since the standing wave in the upper surface film 501 is small, it can be seen that the upward reflection is suppressed.

FIG. 22 shows the results of calculating the reflectance upward with respect to the layer structures shown in FIGS. 20 (a) to 20 (e). Further, the average light intensity (horizontal) from the light receiving surface 137 to the boundary surface of the semiconductor substrate 138 with the upper surface layer 501 (however, the lower surface of the semiconductor substrate 138 if it has a moth-eye structure or a concave-convex structure) to 2 μm (micrometer) in the depth direction. The result of calculating the average in the direction) is shown in FIG. In FIG. 23, the line S1 shows the calculation result of Comparative Example 1, the line S2 shows the calculation result of Comparative Example 2, the line S3 shows the calculation result of Comparative Example 3, and the line S4 is the first. The calculation result of the first embodiment is shown, and the line S5 shows the calculation result of the second embodiment.

As can be seen from FIGS. 22 and 23, Comparative Examples 1 and 3 have higher upward reflectance than other structures. Further, in Comparative Example 1, the average light intensity in the semiconductor substrate 138 is smaller than that of other structures because the reflection to the upper side is large.

In Comparative Example 2, the average light intensity in the semiconductor substrate 138 is larger than that in Comparative Example 1, but is smaller than the average light intensity in Comparative Example 3 and the first and second embodiments. Further, in Comparative Example 2, the slope of the decrease in the average light intensity in the depth direction is small.

In Comparative Examples 3, 1st and 2nd embodiments, the incident light is diffracted and incident on the semiconductor substrate 138, and the light propagates in the semiconductor substrate 138 in the oblique direction, so that the optical path length per unit depth is increased. It has increased. Therefore, the slope of the decrease in the average light intensity in the depth direction is larger than that in Comparative Examples 1 and 2. This means that in Comparative Examples 3, 1st and 2nd embodiments, the amount of light absorbed per depth is large.

From the above, it can be seen that according to the first and second embodiments, both the effects of reducing the upward reflection and increasing the light absorption rate in the semiconductor substrate 138 can be achieved.

6. Target wavelength band In the above-described embodiment, the case where light in the visible region is sensed as incident light L1 is illustrated, but the wavelength band of the target light is not limited to the visible region and is in other wavelength regions. There may be. For example, it may be near infrared with a wavelength of 850 nm or infrared with a longer wavelength. Since near-infrared and infrared light absorbs less than a photodiode PD material such as silicon, the above-described embodiment is considered to be particularly effective. Further, when the target wavelength is a long wavelength, the pitch of the concave-convex structure 150/250 can be increased, so that the effect that the concave-convex structure 150/250 can be easily manufactured can be obtained.

7. Method for Manufacturing Concavo-convex Structure In the concavo-convex structure 150/250 according to the above-described embodiment, for example, a mask having an etching selectivity with that of the semiconductor substrate 138 is formed on the semiconductor substrate 138, and the semiconductor substrate 138 is passed through the mask. For example, it can be formed by etching by anisotropic dry etching. At that time, when forming convex portions (151a and 152a) having different dimensions in the first layer 151 and the second layer 152 as in the concave-convex structure 150, first, the convex portions on the lower layer side are formed through a mask. After forming, it is possible to form convex portions having different dimensions by going through a step of widening the opening of the mask to form a convex portion of the upper layer.

However, the method for forming the concave-convex structure 150/250 is not limited to the above method, and various modifications may be made.

8. Combination with a color filter The unit pixel 110 according to the above-described embodiment can be combined with a color filter, for example. At that time, by combining a color filter that transmits each color component such as a Bayer array with a color filter array that is repeated in a predetermined array, a solid-state image sensor capable of acquiring a color image corresponding to each color filter array is realized. be able to.

FIG. 24 shows an example of a color filter array which is a Bayer array. As shown in FIG. 24, the repeating unit of the color filter array 801 which is the Bayer array has a 2 × 2 array and two color filters 810G which selectively transmit the green wavelength component on one diagonal. Is arranged, and has an array structure in which a color filter 810R that selectively transmits a red wavelength component and a color filter 810B that selectively transmits a blue wavelength component are arranged on the other diagonal. In the following description, when the individual color filters 810R, 810G and 810B are not distinguished, the reference numerals thereof are set to 810.

Such a color filter array 801 is arranged, for example, between the flattening film 133 and the on-chip lens 131 in the cross-sectional structure shown in FIG. At that time, one color filter 810 may be associated with one unit pixel 110, one color filter 810 may be associated with a plurality of unit pixels 110, or a plurality of color filters 810 may be associated with one unit pixel 110. It may be associated with one unit pixel 110. In the following description, a case where one color filter 810 is associated with one unit pixel 110 will be described.

FIG. 25 is a cross-sectional view showing an example of a cross-sectional structure of a unit pixel combined with a color filter that selectively transmits a wavelength component of red (R), and FIG. 26 is a cross-sectional view showing a wavelength component of green (G) selectively. FIG. 27 is a cross-sectional view showing an example of a cross-sectional structure of a unit pixel combined with a color filter that transmits a blue (B) wavelength component. FIG. 27 is a cross-sectional structure of a unit pixel combined with a color filter that selectively transmits a wavelength component of blue (B). It is sectional drawing which shows an example.

In addition, in FIGS. 25 to 27 and the following description, for simplification, the upper layer portion of the semiconductor substrate 138, the insulating film 135, and the color filter 810 will be excerpted and described. Therefore, in FIGS. 25 to 27, the color filter 810 is arranged directly above the insulating film 135, but the color filter 810 may be arranged on the flattening film 133 located on the insulating film 135.

Further, in this description, the case where the concave-convex structure 150 described with reference to FIG. 6 is used as the base in the first embodiment is illustrated, but the present invention is not limited to this, and the other concave-convex structure described in the first embodiment is not limited to this. It is also possible to base on the 150 or the concave-convex structure 250 described in the second embodiment.

As shown in FIGS. 25 to 27, the concave-convex structure 150 of the unit pixel 110R in which the color filter 810R that selectively transmits the red wavelength component is arranged has the pitch and size of the downward convex portion 151a and the upper convex portion 152a. , The color filter 810R is corrected according to the wavelength (for example, the center wavelength) of the red wavelength component selectively transmitted. Similarly, in the concave-convex structure 150 of the unit pixel 110G in which the color filter 810G that selectively transmits the green wavelength component is arranged, the pitch and size of the downward convex portion 151a and the upper convex portion 152a are selectively selected by the color filter 810G. The concave-convex structure 150 of the unit pixel 110B in which the color filter 810B which is corrected according to the wavelength (for example, the center wavelength) of the transmitted green wavelength component and selectively transmits the blue wavelength component is arranged is the downward convex portion 151a. And the pitch and size of the upper convex portion 152a are corrected according to the wavelength (for example, the center wavelength) of the green wavelength component selectively transmitted by the color filter 810B.

FIG. 28 is a graph showing the relationship between the wavelength of incident light and the pitch of the uneven structure. As shown in FIG. 28, when the target wavelength band (hereinafter referred to as the sensing wavelength range) is 400 to 700 nm, the range of the pitch P satisfying the above equation (2) with respect to this sensing wavelength range is shown in FIG. It is the range between the line S11 and the line S12 at 28.

Further, FIG. 29 is a graph showing the relationship between the wavelength of the incident light and the height of the downward convex portion in the first layer of the concave-convex structure. As shown in FIG. 29, when the sensing wavelength is 400 to 700 nm, the height of the downward convex portion 151a satisfying the above equation (4) with respect to this sensing wavelength range is the line S13 and the line S14 in FIG. 29. It is in the range between.

Further, FIG. 30 shows the relationship between the wavelength of the incident light and the volume occupancy of the downward convex portion in the first layer of the concave-convex structure when 1: 1 is set (see equation (3)).

Pitch (formula (2)) and height (formula (3)) with respect to the center wavelength of the target wavelength range of each unit pixel 810R, 810G and 810B so as to satisfy the conditions shown in FIGS. 28 to 30. And when the area ratio (Equation (4)) is optimized, the pitch and dimensions of each are as follows.

For example, in the unit pixel 110R, the pitch of the lower convex portion 151a of the first layer 151 is 165 nm, the height of the lower convex portion 151a is 142 nm, and the upper surface of the lower convex portion 151a and the bottom surface of the concave portion formed by the lower convex portion 151a. The area ratio of the upper convex portion 152a is 1: 1 and the pitch of the upper convex portion 152a of the second layer 152 is 165 nm, the height of the upper convex portion 152a is 87 nm, and the upper surface of the upper convex portion 152a and the upper surface thereof are formed. The area ratio with the bottom surface of the recess is 26.2%.

Similarly, in the unit pixel 110G, the pitch of the lower convex portion 151a of the first layer 151 is 135 nm, the height of the lower convex portion 151a is 119 nm, and the upper surface of the lower convex portion 151a and the bottom surface of the concave portion formed by the lower convex portion 151a. The area ratio is 1: 1 and the pitch of the upper convex portion 152a of the second layer 152 is 135 nm, the height of the upper convex portion 152a is 76 nm, and the upper surface of the upper convex portion 152a and it are The area ratio with the bottom surface of the recess to be formed is 26.3%.

Similarly, in the unit pixel 110B, the pitch of the lower convex portion 151a of the first layer 151 is 105 nm, the height of the lower convex portion 151a is 75 nm, and the upper surface of the lower convex portion 151a and the bottom surface of the concave portion formed by the lower convex portion 151a. The area ratio is 1: 1 and the pitch of the upper convex portion 152a of the second layer 152 is 105 nm, the height of the upper convex portion 152a is 56 nm, and the upper surface of the upper convex portion 152a and it are The area ratio with the bottom surface of the recess to be formed is 26.6%.

9. Application example to mobile body 1
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 is realized as a device mounted on a moving body of any kind such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, and a robot. You may.

FIG. 31 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technique according to the present disclosure can be applied.

The vehicle control system 12000 includes a plurality of electronic control units connected via the communication network 12001. In the example shown in FIG. 31, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside information detection unit 12030, an in-vehicle information detection unit 12040, and an integrated control unit 12050. Further, as a functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio image output unit 12052, and an in-vehicle network I / F (Interface) 12053 are shown.

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

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

The vehicle exterior information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, the image pickup unit 12031 is connected to the vehicle exterior information detection unit 12030. The vehicle outside information detection unit 12030 causes the image pickup unit 12031 to capture an image of the outside of the vehicle and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing such as a person, a vehicle, an obstacle, a sign, or characters on the road surface based on the received image.

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

The in-vehicle information detection unit 12040 detects information in the vehicle. For example, a driver state detection unit 12041 that detects the driver's state is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 determines the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether the driver is dozing.

The microcomputer 12051 calculates the control target value of the driving force generator, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and the drive system control unit. A control command can be output to 12010. For example, the microcomputer 12051 realizes ADAS (Advanced Driver Assistance System) functions including vehicle collision avoidance or impact mitigation, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane deviation warning, and the like. It is possible to perform cooperative control for the purpose of.

Further, the microcomputer 12051 controls the driving force generator, the steering mechanism, the braking device, and the like based on the information around the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, so that the driver can control the driver. It is possible to perform coordinated control for the purpose of automatic driving that runs autonomously without depending on the operation.

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

The audio-image output unit 12052 transmits an output signal of at least one of audio and an image to an output device capable of visually or audibly notifying the passenger of the vehicle or the outside of the vehicle. In the example of FIG. 31, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as output devices. The display unit 12062 may include, for example, at least one of an onboard display and a heads-up display.

FIG. 32 is a diagram showing an example of the installation position of the imaging unit 12031.

In FIG. 32, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as, for example, the front nose, side mirrors, rear bumpers, back doors, and the upper part of the windshield in the vehicle interior of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the upper part of the windshield in the vehicle interior mainly acquire an image in front of the vehicle 12100. The imaging units 12102 and 12103 provided in the side mirrors mainly acquire images of the side of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or the back door mainly acquires an image of the rear of the vehicle 12100. The imaging unit 12105 provided on the upper part of the windshield in the vehicle interior is mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

Note that FIG. 32 shows an example of the photographing range of the imaging units 12101 to 12104. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, the imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and the imaging range 12114 indicates the imaging range of the imaging units 12102 and 12103. The imaging range of the imaging unit 12104 provided on the rear bumper or the back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 as viewed from above can be obtained.

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

For example, the microcomputer 12051 has a distance to each three-dimensional object within the imaging range 12111 to 12114 based on the distance information obtained from the imaging units 12101 to 12104, and a temporal change of this distance (relative velocity with respect to the vehicle 12100). By obtaining, it is possible to extract as the preceding vehicle a three-dimensional object that is the closest three-dimensional object on the traveling path of the vehicle 12100 and that travels in substantially the same direction as the vehicle 12100 at a predetermined speed (for example, 0 km / h or more). it can. Further, the microcomputer 12051 can set an inter-vehicle distance to be secured in front of the preceding vehicle in advance, and can perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. In this way, it is possible to perform coordinated control for the purpose of automatic driving or the like in which the vehicle travels autonomously without depending on the operation of the driver.

For example, the microcomputer 12051 converts three-dimensional object data related to a three-dimensional object into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, electric poles, and other three-dimensional objects based on the distance information obtained from the imaging units 12101 to 12104. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that can be seen by the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines the collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, the microcomputer 12051 via the audio speaker 12061 or the display unit 12062. By outputting an alarm to the driver and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be provided.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured image of the imaging units 12101 to 12104. Such pedestrian recognition includes, for example, a procedure for extracting feature points in an image captured by an imaging unit 12101 to 12104 as an infrared camera, and pattern matching processing for a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. It is done by the procedure to determine. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 outputs a square contour line for emphasizing the recognized pedestrian. The display unit 12062 is controlled so as to superimpose and display. Further, the audio image output unit 12052 may control the display unit 12062 so as to display an icon or the like indicating a pedestrian at a desired position.

The example of the vehicle control system to which the technique according to the present disclosure can be applied has been described above. The technique according to the present disclosure can be applied to the imaging unit 12031 and the like among the configurations described above. By applying the technique according to the present disclosure to the imaging unit 12031, it is possible to obtain a photographed image that is easier to see, and thus it is possible to reduce driver fatigue.

10. Examples of application to endoscopic surgery systems The technology according to the present disclosure (this technology) can be applied to various products. For example, the techniques according to the present disclosure may be applied to endoscopic surgery systems.

FIG. 33 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technique according to the present disclosure (the present technique) can be applied.

FIG. 33 shows a surgeon (doctor) 11131 performing surgery on patient 11132 on patient bed 11133 using the endoscopic surgery system 11000. As shown, the endoscopic surgery system 11000 includes an endoscope 11100, other surgical tools 11110 such as an abdominal tube 11111 and an energy treatment tool 11112, and a support arm device 11120 that supports the endoscope 11100. , A cart 11200 equipped with various devices for endoscopic surgery.

The endoscope 11100 is composed of a lens barrel 11101 in which a region having a predetermined length from the tip is inserted into the body cavity of the patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the illustrated example, the endoscope 11100 configured as a so-called rigid mirror having a rigid barrel 11101 is illustrated, but the endoscope 11100 may be configured as a so-called flexible mirror having a flexible barrel. Good.

An opening in which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and the light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101 to be an objective. It is irradiated toward the observation target in the body cavity of the patient 11132 through the lens. The endoscope 11100 may be a direct endoscope, a perspective mirror, or a side endoscope.

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

The CCU11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and the like, and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Further, the CCU 11201 receives an image signal from the camera head 11102, and performs various image processing on the image signal for displaying an image based on the image signal, such as development processing (demosaic processing).

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

The light source device 11203 is composed of, for example, a light source such as an LED (light emitting diode), and supplies irradiation light for photographing an operating part or the like to the endoscope 11100.

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

The treatment tool control device 11205 controls the drive of the energy treatment tool 11112 for cauterizing, incising, sealing a blood vessel, or the like of a tissue. The pneumoperitoneum device 11206 uses a gas in the pneumoperitoneum tube 11111 to inflate the body cavity of the patient 11132 for the purpose of securing the field of view by the endoscope 11100 and securing the work space of the operator. To send. Recorder 11207 is a device capable of recording various information related to surgery. The printer 11208 is a device capable of printing various information related to surgery in various formats such as text, images, and graphs.

The light source device 11203 that supplies the irradiation light to the endoscope 11100 when photographing the surgical site can be composed of, for example, an LED, a laser light source, or a white light source composed of a combination thereof. When a white light source is configured by combining RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high accuracy. Therefore, the light source device 11203 adjusts the white balance of the captured image. It can be carried out. Further, in this case, the laser light from each of the RGB laser light sources is irradiated to the observation target in a time-division manner, and the drive of the image sensor of the camera head 11102 is controlled in synchronization with the irradiation timing to correspond to each of RGB. It is also possible to capture the image in a time-division manner. According to this method, a color image can be obtained without providing a color filter on the image sensor.

Further, the drive of the light source device 11203 may be controlled so as to change the intensity of the output light at predetermined time intervals. By controlling the drive of the image sensor of the camera head 11102 in synchronization with the timing of changing the light intensity to acquire an image in a time-divided manner and synthesizing the image, so-called high dynamic without blackout and overexposure. Range images can be generated.

Further, the light source device 11203 may be configured to be able to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in body tissue to irradiate light in a narrow band as compared with the irradiation light (that is, white light) in normal observation, the surface layer of the mucous membrane. So-called narrow band imaging, in which a predetermined tissue such as a blood vessel is photographed with high contrast, is performed. Alternatively, in the special light observation, fluorescence observation may be performed in which an image is obtained by fluorescence generated by irradiating with excitation light. In fluorescence observation, the body tissue is irradiated with excitation light to observe the fluorescence from the body tissue (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and the body tissue is injected. It is possible to obtain a fluorescence image by irradiating excitation light corresponding to the fluorescence wavelength of the reagent. The light source device 11203 may be configured to be capable of supplying narrow band light and / or excitation light corresponding to such special light observation.

FIG. 34 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU11201 shown in FIG. 33.

The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a driving unit 11403, a communication unit 11404, and a camera head control unit 11405. CCU11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and CCU11201 are communicatively connected to each other by a transmission cable 11400.

The lens unit 11401 is an optical system provided at a connection portion with the lens barrel 11101. The observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and incident on the lens unit 11401. The lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

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

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

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

The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU11201. The communication unit 11404 transmits the image signal obtained from the image pickup unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

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

The above-mentioned imaging conditions such as frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of CCU11201 based on the acquired image signal. Good. In the latter case, the so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function are mounted on the endoscope 11100.

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

The communication unit 11411 is composed of a communication device for transmitting and receiving various types of information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

Further, the communication unit 11411 transmits a control signal for controlling the drive of the camera head 11102 to the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communication, or the like.

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

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

Further, the control unit 11413 causes the display device 11202 to display the captured image in which the surgical unit or the like is reflected, based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image by using various image recognition techniques. For example, the control unit 11413 detects the shape, color, and the like of the edge of an object included in the captured image to remove surgical tools such as forceps, a specific biological part, bleeding, and mist when using the energy treatment tool 11112. Can be recognized. When displaying the captured image on the display device 11202, the control unit 11413 may superimpose and display various surgical support information on the image of the surgical unit by using the recognition result. By superimposing and displaying the surgical support information and presenting it to the surgeon 11131, it is possible to reduce the burden on the surgeon 11131 and to allow the surgeon 11131 to proceed with the surgery reliably.

The transmission cable 11400 connecting the camera head 11102 and CCU11201 is an electric signal cable corresponding to electric signal communication, an optical fiber corresponding to optical communication, or a composite cable thereof.

Here, in the illustrated example, the communication is performed by wire using the transmission cable 11400, but the communication between the camera head 11102 and the CCU11201 may be performed wirelessly.

The example of the endoscopic surgery system to which the technique according to the present disclosure can be applied has been described above. The technique according to the present disclosure can be applied to, for example, the image pickup unit 11402 of the camera head 11102 among the configurations described above. By applying the technique according to the present disclosure to the camera head 11102, a clearer surgical site image can be obtained, so that the operator can surely confirm the surgical site.

Although the endoscopic surgery system has been described here as an example, the technique according to the present disclosure may be applied to other, for example, a microscopic surgery system.

Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments as they are, and various changes can be made without departing from the gist of the present disclosure. In addition, components covering different embodiments and modifications may be combined as appropriate.

Further, the effects in each of the embodiments described in the present specification are merely examples and are not limited, and other effects may be obtained.

前記（２）又は（３）に記載の固体撮像装置。
（５）
前記凸部と前記凹部とは、前記凸部の底面から上面までの高さをＨ_１１とした場合、以下の式（１５）及び式（１６）に近づくように設計されている

前記（４）に記載の固体撮像装置。
（６）
前記第２層は、前記光の入射面と平行な平面に配列する微細な凹凸を含む前記（１）〜（５）の何れか１項に記載の固体撮像装置。
（７）
前記第２層は、前記第１絶縁膜の屈折率をｎ_Ｕとし、前記第１層の実効屈折率をｎｅｆｆ１１とし、当該第２層の実効屈折率をｎｅｆｆ１２とした場合、以下の式（１７）に近づくように設計されている

前記（６）に記載の固体撮像装置。
（８）
前記第２層は、前記微細な凹凸の底面から上面までの高さをＨ_１２とした場合、以下の式（１８）に近づくように設計されている

前記（７）に記載の固体撮像装置。
（９）
前記第１層の前記凸部は、前記半導体基板の前記光の入射面に形成されたストライプ状の凸部である前記（４）又は（５）に記載の固体撮像装置。
（１０）
前記凸部は、前記半導体基板の前記光の入射面に形成されたドット状の凸部である前記（４）又は（５）に記載の固体撮像装置。
（１１）
前記第２層は、前記光の入射面と平行な平面に配列する微細な凹凸を含み、
前記第２層の前記微細な凹凸は、前記ストライプ状の前記凸部上に設けられ、当該凸部と同一方向に延在するストライプ状の凸部を含む
前記（９）に記載の固体撮像装置。
（１２）
前記第２層は、前記光の入射面と平行な平面に配列する微細な凹凸を含み、
前記第２層の前記微細な凹凸は、前記第１層の前記凸部上に設けられたドット状の凸部を含む
前記（９）又は（１０）に記載の固体撮像装置。
（１３）
前記回折格子は、前記半導体基板における前記光の入射面に形成された凸部と凹部とで構成され、
前記第２層は、前記凹部の内部並びに前記凸部及び前記凹部上に設けられた第２絶縁膜よりなり、
前記凸部と前記凹部とのピッチＰは、前記半導体基板の屈折率をｎ_ｐ、前記第２絶縁膜の屈折率をｎ_Ｍ、入射光の波長をλ_０とした場合、以下の式（１９）を満たすように設計されている

前記（２）又は（３）に記載の固体撮像装置。
（１４）
前記凸部と前記凹部とは、前記凸部の底面から上面までの高さをＨ_２１とした場合、以下の式（２０）及び式（２１）に近づくように設計されている

前記（１３）に記載の固体撮像装置。
（１５）
前記第２層は、前記第１絶縁膜の屈折率をｎ_Ｕとし、前記第１層の実効屈折率をｎｅｆｆ１１とした場合、以下の式（２２）に近づくように設計されている

前記（１３）又は（１４）に記載の固体撮像装置。
（１６）
前記第２層は、前記第１層の上面から当該第２層の上面までの高さをＨ_Ｍとした場合、以下の式（２３）に近づくように設計されている

前記（１５）に記載の固体撮像装置。
（１７）
前記半導体基板は、
複数の前記光電変換部と、
前記複数の光電変換部の間に設けられ、前記複数の光電変換部間を光学的に分離する画素分離部と、
を備える前記（１）〜（１６）の何れか１項に記載の固体撮像装置。
（１８）
前記凹凸構造を挟んで前記光電変換素子と反対側に配置され、所定の波長帯域の光を透過させるカラーフィルタをさらに備える前記（１）〜（１７）の何れか１項に記載の固体撮像装置。
（１９）
前記半導体基板は、複数の前記光電変換部が行列状に配列する画素アレイ部を備え、
前記凹凸構造は、前記画素アレイ部における位置に応じて補正されている
前記（１）〜（１８）の何れか１項に記載の固体撮像装置。
（２０）
複数の単位画素が行列方向に配列した画素アレイ部と、
前記複数の単位画素における読出し対象の単位画素を駆動する駆動回路と、
前記駆動回路により駆動された前記読出し対象の単位画素から画素信号を読み出す処理回路と、
前記駆動回路及び前記処理回路を制御する制御部と、
を備え、
前記単位画素は、
半導体基板に設けられた光電変換部と、
前記半導体基板に対して前記光電変換部への光の入射面側に位置する第１絶縁膜と、
前記光電変換部と前記第１絶縁膜との間に位置する凹凸構造と、
を備え、
前記凹凸構造は、
前記光電変換部側に位置し、前記光電変換部へ入射する光を回折させる第１層と、
前記第１絶縁膜側に位置し、前記第１絶縁膜側への反射を抑制する第２層と、
を備える電子機器。 The present technology can also have the following configurations.
(1)
The photoelectric conversion unit provided on the semiconductor substrate and
A first insulating film located on the incident surface side of the light incident on the photoelectric conversion unit with respect to the semiconductor substrate,
An uneven structure located between the photoelectric conversion unit and the first insulating film,
With
The uneven structure
A first layer located on the photoelectric conversion unit side and diffracting light incident on the photoelectric conversion unit, and
A second layer located on the first insulating film side and suppressing reflection to the first insulating film side,
A solid-state image sensor.
(2)
The solid-state image sensor according to (1) above, wherein the first layer is a diffraction grating.
(3)
The solid-state imaging device according to (2) above, wherein the diffraction grating is designed so that the intensity of non-diffraction light among the light incident on the photoelectric conversion unit approaches zero.
(4)
The diffraction grating is composed of convex portions and concave portions formed on the incident surface of the light on the semiconductor substrate.
The pitch P between the convex portion and the concave portion is calculated by the following equation (13) when _{the refractive index of the semiconductor substrate is n p} , the refractive index of the first insulating film is n _U , and the wavelength of the incident light is λ _0. ) And equation (14)

The solid-state image sensor according to (2) or (3) above.
(5)
Wherein a convex portion and the concave portion, if the height from the bottom surface of the convex portion to the top face and the H _11, are designed to approach the following equation (15) and (16)

The solid-state image sensor according to (4) above.
(6)
The solid-state image sensor according to any one of (1) to (5) above, wherein the second layer includes fine irregularities arranged on a plane parallel to the incident surface of the light.
(7)
And the second layer, the refractive index of the first insulating film as a _{n U,} the effective refractive index of the first layer and Neff11, when the effective refractive index of the second layer and Neff12, the following equation (17 ) Is designed to approach

The solid-state image sensor according to (6) above.
(8)
The second layer, if the height from the bottom surface of the fine irregularities to the top face and the H _12, are designed to approach the following equation (18)

The solid-state image sensor according to (7) above.
(9)
The solid-state image sensor according to (4) or (5), wherein the convex portion of the first layer is a striped convex portion formed on the incident surface of the light of the semiconductor substrate.
(10)
The solid-state image sensor according to (4) or (5) above, wherein the convex portion is a dot-shaped convex portion formed on the incident surface of the light of the semiconductor substrate.
(11)
The second layer contains fine irregularities arranged in a plane parallel to the incident surface of the light.
The solid-state image sensor according to (9), wherein the fine unevenness of the second layer is provided on the striped convex portion and includes a striped convex portion extending in the same direction as the convex portion. ..
(12)
The second layer contains fine irregularities arranged in a plane parallel to the incident surface of the light.
The solid-state image sensor according to (9) or (10), wherein the fine unevenness of the second layer includes a dot-shaped convex portion provided on the convex portion of the first layer.
(13)
The diffraction grating is composed of convex portions and concave portions formed on the incident surface of the light on the semiconductor substrate.
The second layer is composed of the inside of the concave portion and the convex portion and the second insulating film provided on the concave portion.
Pitch P of the concave and the convex portion, the refractive index of the semiconductor substrate n _p, if the refractive index of the second insulating film was n _M, the wavelength of the incident light lambda _0, the following equation (19 ) Is designed to meet

The solid-state image sensor according to (2) or (3) above.
(14)
Wherein a convex portion and the concave portion, if the height from the bottom surface of the convex portion to the top face and the H _21, are designed to approach the following equation (20) and (21)

The solid-state image sensor according to (13) above.
(15)
The second layer, the refractive index of the first insulating film as a n _U, when the effective refractive index of the first layer and Neff11, are designed to approach the following equation (22)

The solid-state image sensor according to (13) or (14).
(16)
The second layer, if said the height from the upper surface of the first layer to the upper surface of the second layer and H _M, are designed to approach the following equation (23)

The solid-state image sensor according to (15) above.
(17)
The semiconductor substrate is
With the plurality of photoelectric conversion units
A pixel separation unit provided between the plurality of photoelectric conversion units and optically separating the plurality of photoelectric conversion units,
The solid-state image sensor according to any one of (1) to (16) above.
(18)
The solid-state image pickup device according to any one of (1) to (17), further comprising a color filter that is arranged on the opposite side of the photoelectric conversion element with the uneven structure interposed therebetween and transmits light in a predetermined wavelength band. ..
(19)
The semiconductor substrate includes a pixel array unit in which a plurality of the photoelectric conversion units are arranged in a matrix.
The solid-state image sensor according to any one of (1) to (18), wherein the uneven structure is corrected according to a position in the pixel array portion.
(20)
A pixel array section in which multiple unit pixels are arranged in the matrix direction,
A drive circuit that drives the unit pixel to be read in the plurality of unit pixels, and
A processing circuit that reads a pixel signal from the unit pixel to be read, which is driven by the drive circuit, and
A control unit that controls the drive circuit and the processing circuit,
With
The unit pixel is
The photoelectric conversion unit provided on the semiconductor substrate and
A first insulating film located on the incident surface side of the light incident on the photoelectric conversion unit with respect to the semiconductor substrate,
An uneven structure located between the photoelectric conversion unit and the first insulating film,
With
The uneven structure
A first layer located on the photoelectric conversion unit side and diffracting light incident on the photoelectric conversion unit, and
A second layer located on the first insulating film side and suppressing reflection to the first insulating film side,
Electronic equipment equipped with.

1 Electronic equipment 10 Imaging lens 20 Processor 30 Storage unit 100 Solid-state imaging device 101 Pixel array unit 102 Vertical drive circuit 103 Column processing circuit 104 Horizontal drive circuit 105 System control unit 108 Signal processing unit 109 Data storage unit 110, 110B, 110G, 110R Unit pixel 111 Transfer transistor 112 Reset transistor 113 Amplification transistor 114 Select transistor 121 Light receiving chip 122 Circuit chip 131 On-chip lens 133 Flattening film 134 Light-shielding film 135 Insulating film 136, 144 P-type semiconductor area 137 Light-receiving surface 138 Semiconductor substrate 139 N-type Semiconductor area 140 Pixel separation part 141 Groove part 142 Fixed charge film 143 Insulation film 145 Wiring layer 146 Wiring 147 Insulation layer 150, 250 Concavo-convex structure 151, 251 First layer 151a Lower convex part 152, 252 Second layer 152a Upper convex part 810 Color Filter arrangement 810B, 810G, 810R Color filter 1521, 252a Lower layer 1521a First upper convex part 1522, 252b Upper layer 1522a Second upper convex part L1 Incident light L2 Reflected light L10 Non-diffractive light L11 Diffractive light LD Pixel drive line PD Transistor VSL Vertical signal line

Claims (20)

The photoelectric conversion unit provided on the semiconductor substrate and
A first insulating film located on the incident surface side of the light incident on the photoelectric conversion unit with respect to the semiconductor substrate,
An uneven structure located between the photoelectric conversion unit and the first insulating film,
With
The uneven structure
A first layer located on the photoelectric conversion unit side and diffracting light incident on the photoelectric conversion unit, and
A second layer located on the first insulating film side and suppressing reflection to the first insulating film side,
A solid-state image sensor. The solid-state image sensor according to claim 1, wherein the first layer is a diffraction grating. The solid-state imaging device according to claim 2, wherein the diffraction grating is designed so that the intensity of non-diffraction light among the light incident on the photoelectric conversion unit approaches zero. The diffraction grating is composed of convex portions and concave portions formed on the incident surface of the light on the semiconductor substrate.
The pitch P between the convex portion and the concave portion is calculated by the following equation (1) when _{the refractive index of the semiconductor substrate is n p} , the refractive index of the first insulating film is n _U , and the wavelength of the incident light is λ _0. ) And equation (2)

The solid-state image sensor according to claim 2. Wherein a convex portion and the concave portion, if the height from the bottom surface of the convex portion to the top face and the H _11, are designed to approach the following equation (3) and (4)

The solid-state image sensor according to claim 4. The solid-state image sensor according to claim 1, wherein the second layer includes fine irregularities arranged on a plane parallel to the incident surface of the light. And the second layer, the refractive index of the first insulating film as a n _U, the effective refractive index of the first layer and Neff11, when the effective refractive index of the second layer and Neff12, the following equation (5 ) Is designed to approach

The solid-state image sensor according to claim 6. The second layer, if the height from the bottom surface of the fine irregularities to the top face and the H _12, are designed to approach the following equation (6)

The solid-state image sensor according to claim 7. The solid-state image sensor according to claim 4, wherein the convex portion of the first layer is a striped convex portion formed on the incident surface of the light of the semiconductor substrate. The solid-state image sensor according to claim 4, wherein the convex portion is a dot-shaped convex portion formed on the incident surface of the light of the semiconductor substrate. The second layer contains fine irregularities arranged in a plane parallel to the incident surface of the light.
The solid-state image sensor according to claim 9, wherein the fine unevenness of the second layer is provided on the striped convex portion and includes a striped convex portion extending in the same direction as the convex portion. The second layer contains fine irregularities arranged in a plane parallel to the incident surface of the light.
The solid-state image sensor according to claim 9, wherein the fine unevenness of the second layer includes a dot-shaped convex portion provided on the convex portion of the first layer. The diffraction grating is composed of convex portions and concave portions formed on the incident surface of the light on the semiconductor substrate.
The second layer is composed of the inside of the concave portion and the convex portion and the second insulating film provided on the concave portion.
Pitch P of the concave and the convex portion, the refractive index of the semiconductor substrate n _p, if the refractive index of the second insulating film was n _M, the wavelength of the incident light lambda _0, the following equation (7 ) Is designed to meet

The solid-state image sensor according to claim 2. Wherein a convex portion and the concave portion, if the height from the bottom surface of the convex portion to the top face and the H _21, are designed to approach the following equation (8) and (9)

The solid-state image sensor according to claim 13. The second layer, the refractive index of the first insulating film as a n _U, when the effective refractive index of the first layer and Neff11, are designed to approach the following equation (10)

The solid-state image sensor according to claim 13. The second layer, if said the height from the upper surface of the first layer to the upper surface of the second layer and H _M, are designed to approach the equation (11) below

The solid-state image sensor according to claim 15. The semiconductor substrate is
With the plurality of photoelectric conversion units
A pixel separation unit provided between the plurality of photoelectric conversion units and optically separating the plurality of photoelectric conversion units,
The solid-state image sensor according to claim 1. The solid-state image pickup device according to claim 1, further comprising a color filter that is arranged on the opposite side of the photoelectric conversion element with the uneven structure interposed therebetween and transmits light in a predetermined wavelength band. The semiconductor substrate includes a pixel array unit in which a plurality of the photoelectric conversion units are arranged in a matrix.
The solid-state image sensor according to claim 1, wherein the uneven structure is corrected according to a position in the pixel array portion. A pixel array section in which multiple unit pixels are arranged in the matrix direction,
A drive circuit that drives the unit pixel to be read in the plurality of unit pixels, and
A processing circuit that reads a pixel signal from the unit pixel to be read, which is driven by the drive circuit, and
A control unit that controls the drive circuit and the processing circuit,
With
The unit pixel is
The photoelectric conversion unit provided on the semiconductor substrate and
A first insulating film located on the incident surface side of the light incident on the photoelectric conversion unit with respect to the semiconductor substrate,
An uneven structure located between the photoelectric conversion unit and the first insulating film,
With
The uneven structure
A first layer located on the photoelectric conversion unit side and diffracting light incident on the photoelectric conversion unit, and
A second layer located on the first insulating film side and suppressing reflection to the first insulating film side,
Electronic equipment equipped with.

Images