Solid-state image sensor, solid-state imaging device, and method for manufacturing solid-state image sensor

Abstract

The present invention provides a solid-state image sensor (100), comprising a semiconductor substrate (500), a charge accumulator arranged in the semiconductor substrate (500) and accumulating charges, a photoelectric converter (200) arranged above the semiconductor substrate (500) and converting light into charges, and a through-electrode (600) passing through the semiconductor substrate (500) and electrically connecting the charge accumulator to the photoelectric converter (200). At an end of the through-electrode (600) on the photoelectric converter side, a conductor (602) located at the center of the through-electrode (600) has a cross-sectional area (602) in a cut section orthogonal to a through-direction of the through-electrode (600) that gradually increases along the through-direction toward the photoelectric converter.

Description

Technical Field

[0001] The present invention relates to a solid-state image sensor, a solid-state imaging device and a method for manufacturing the solid-state image sensor. Background Art

[0002] In solid-state image sensors such as charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors, it has been considered to provide a through electrode for each pixel (solid-state image sensor). An example of such a solid-state image sensor is a solid-state image sensor disclosed in the following patent document 1.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: JP 2017-073436 A Summary of the invention

[0006] Technical issues

[0007] Unfortunately, in the through-electrode disclosed in the above-mentioned Patent Document 1, it is difficult to maintain a low resistance value of the through-electrode.

[0008] In view of such circumstances, the present invention proposes a novel and improved solid-state image sensor having a through electrode maintaining a low resistance value, a solid-state imaging device, and a method of manufacturing the solid-state image sensor.

[0009] Problem Solution

[0010] According to the present invention, there is provided a solid-state image sensor, comprising: a semiconductor substrate; a charge accumulator arranged in the semiconductor substrate, which is used to accumulate charges; a photoelectric converter arranged above the semiconductor substrate, which is used to convert light into charges; and a through-electrode, which passes through the semiconductor substrate and electrically connects the charge accumulator with the photoelectric converter, wherein, at the end of the through-electrode on the side of the photoelectric converter, the cross-sectional area of ​​the conductor located at the center of the through-electrode in a cut section orthogonal to the through-direction of the through-electrode gradually increases along the through-direction toward the photoelectric converter.

[0011] In addition, according to the present invention, a solid-state imaging device is provided, which includes a plurality of solid-state image sensors arranged in a matrix, each of the solid-state image sensors including: a semiconductor substrate; a charge accumulator arranged in the semiconductor substrate, which is used to accumulate charges; a photoelectric converter arranged above the semiconductor substrate, which is used to convert light into charges; and a through-electrode, which passes through the semiconductor substrate and electrically connects the charge accumulator to the photoelectric converter, wherein, at the end of the through-electrode on the side of the photoelectric converter, the cross-sectional area of ​​the conductor located at the center of the through-electrode in a cut section orthogonal to the through-direction of the through-electrode gradually increases along the through-direction toward the photoelectric converter.

[0012] In addition, according to the present invention, a method for manufacturing a solid-state image sensor is provided, the image sensor comprising: a semiconductor substrate; a charge accumulator arranged in the semiconductor substrate, which is used to accumulate charges; a photoelectric converter arranged above the semiconductor substrate, which is used to convert light into charges; and a through-electrode, which passes through the semiconductor substrate and electrically connects the charge accumulator with the photoelectric converter, wherein, at the end of the through-electrode on the side of the photoelectric converter, the cross-sectional area of ​​the conductor located at the center of the through-electrode in a cutting section orthogonal to the through-direction of the through-electrode gradually increases along the through-direction toward the photoelectric converter, the method comprising: forming a through hole passing through the semiconductor substrate; depositing an insulating film to cover the inner wall of the through hole; etching the insulating film at the end of the through hole on the side of the photoelectric converter; and filling the through hole with a metal film.

[0013] Advantageous Effects of the Invention

[0014] As described above, the present invention can maintain a low resistance value of the through-electrode.

[0015] The above-described effects are not necessarily limitative, and in addition to the above-described effects, any effects shown in this specification or other effects that can be explained based on this specification can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : is a plan view schematically showing a solid-state imaging device 1 according to an embodiment of the present invention.

[0017] Figure 2 2 is an equivalent circuit diagram of the PD 200 included in the solid-state image sensor 100 according to the embodiment of the present invention.

[0018] Figure 3 is an equivalent circuit diagram of the PD 300 included in the solid-state image sensor 100 according to the embodiment of the present invention.

[0019] Figure 4 is a cross-sectional view of a solid-state image sensor 100 according to an embodiment of the present invention.

[0020] Figure 5 is a diagram used to explain the circumstances leading to the creation of an embodiment of the present invention.

[0021] Figure 6 is a partially enlarged view of a cross section of the solid-state image sensor 100 according to the first embodiment of the present invention.

[0022] Figure 7 It is along Figure 6 FIG. 6 is a cross-sectional view of the through-electrode 600 cut along the line AA′ and the line BB′ in FIG.

[0023] Figure 8 is a diagram schematically showing an upper portion of a through electrode 600 according to the first embodiment of the present invention.

[0024] Fig. 9 FIG. 1 is a diagram for explaining a method of manufacturing a solid-state image sensor 100 according to a first embodiment of the present invention.

[0025] Fig.10 FIG. (2) is a diagram for explaining the method of manufacturing the solid-state image sensor 100 according to the first embodiment of the present invention.

[0026] Fig.11 FIG. 3 is a diagram for explaining the method for manufacturing the solid-state image sensor 100 according to the first embodiment of the present invention.

[0027] Fig.12 FIG. (4) is a diagram for explaining the method of manufacturing the solid-state image sensor 100 according to the first embodiment of the present invention.

[0028] Fig.13 FIG. 5 is a diagram for explaining the method for manufacturing the solid-state image sensor 100 according to the first embodiment of the present invention.

[0029] Fig.14 is a cross-sectional view of a solid-state image sensor 100a according to a second embodiment of the present invention.

[0030] Fig.15 is a diagram schematically showing an upper portion of a through electrode 600 a according to a second embodiment of the present invention.

[0031] Fig.16 is a diagram schematically showing an upper portion of a through electrode 600 b according to a third embodiment of the present invention.

[0032] Fig.17 is a cross-sectional view of a solid-state image sensor 100b according to a fourth embodiment of the present invention.

[0033] Fig.18 is a diagram showing an example of an electronic device 900 according to a fifth embodiment of the present invention.

[0034] Fig.19 is a diagram showing an example of the overall configuration of an endoscopic surgery system.

[0035] Fig. 20 is a block diagram showing an example of the functional configuration of a camera head and a CCU.

[0036] Fig.21 is a diagram showing an example of an overall configuration of a vehicle control system.

[0037] Fig. 22 is a diagram showing an example of the installation positions of the vehicle exterior information detector and the imager. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, constituent elements having substantially the same functional configuration are denoted by the same reference symbols, and repeated descriptions are omitted.

[0039] In this specification and the accompanying drawings, similar components in different embodiments may be represented by the same reference symbol followed by different alphabets to distinguish them from each other. However, when similar components do not need to be distinguished from each other, they are represented by the same reference symbol only.

[0040] The drawings referred to in the following description are for the purpose of illustrating the embodiments of the present invention and for ease of understanding, and the shapes, sizes, and ratios shown in the drawings may be different from the actual ones for ease of understanding. The solid-state image sensors and solid-state imaging devices shown in the drawings may be appropriately modified in consideration of the following description and known techniques. In the description using the cross-sectional view of the solid-state image sensor, the up-down direction of the stacked structure of the solid-state image sensor corresponds to the relative direction when the light incident surface of the incoming light of the solid-state image sensor is the upper side, and may be different from the up-down direction consistent with the actual acceleration of gravity.

[0041] The specific size or shape in the following description does not refer only to the same value as the mathematically defined numerical value or the geometrically defined shape, but includes industrially acceptable differences in the manufacturing process of the solid-state image sensor or shapes similar to the specific shape. For example, in the following description, the expression "cylindrical" or "substantially cylindrical" is not limited to a cylinder whose top and bottom shapes are perfect circles, but also refers to a cylinder whose top and bottom shapes are similar to perfect circles (e.g., ellipses).

[0042] In the following description of circuit configuration, "electrical connection" means connecting multiple elements to each other so as to establish electrical continuity, unless otherwise specified. In addition, "electrical connection" in the following description includes not only directly connecting multiple elements electrically, but also indirectly connecting these elements electrically through another element.

[0043] In the following description, "gate" represents the gate electrode of a field effect transistor (FET). "Drain" means the drain electrode or drain region of a FET, and "source" refers to the source electrode or source region of a FET.

[0044] The description will be given in the following order.

[0045] 1. Overall Configuration of Solid-State Imaging Device 1

[0046] 2. Equivalent Circuit of Solid State Image Sensor 100

[0047] 3. Stacked Structure of Solid-State Image Sensor 100

[0048] 4. Circumstances leading to the implementation of the present invention

[0049] 5. First embodiment

[0050] 5.1 Detailed Structure of Through-Electrode 600

[0051] 5.2 Method for Manufacturing Solid-State Image Sensor 100

[0052] 5.3 Variations

[0053] 6. Second Embodiment

[0054] 7. Third embodiment

[0055] 8. Fourth embodiment

[0056] 9. Fifth embodiment

[0057] 10. Summary

[0058] 11. Application in endoscopic surgery system

[0059] 12. Application on movable objects

[0060] 13. Additional Notes

[0061] <<1. Overall Configuration of Solid-State Imaging Device 1>>

[0062] First, before describing the embodiments according to the present invention, Figure 1 The overall configuration of the solid-state imaging device 1 according to the embodiment of the present invention is described. Figure 1 1 is a plan view schematically showing a solid-state imaging device 1 according to the present embodiment. Figure 1As shown, the solid-state imaging device 1 according to the present embodiment includes a pixel array 10 in which a plurality of solid-state image sensors (pixels) 100 are arranged in a matrix on a semiconductor substrate 500 made of, for example, silicon. Figure 1 As shown, the solid-state imaging device 1 further includes a vertical drive circuit 32, a column signal processing circuit 34, a horizontal drive circuit 36, an output circuit 38, and a control circuit 40. Details of each block of the solid-state imaging device 1 according to the present embodiment will be described below.

[0063] (Pixel Array 10)

[0064] The pixel array 10 has a plurality of solid-state image sensors 100 arranged two-dimensionally in a matrix (columns and rows) on a semiconductor substrate 500. As used herein, the "solid-state image sensor 100" refers to a solid-state image sensor (unit pixel) regarded as a unit that detects light of each color and outputs a result of each color each time it outputs a detection result. Each solid-state image sensor 100 includes a plurality of photoelectric conversion elements (photodiodes (PD)) (photoelectric converters) (e.g., such as Figure 4 As shown, the solid-state image sensor 100 may include three stacked PDs 200, 300, and 400) and a plurality of pixel transistors (eg, metal oxide semiconductor (MOS) transistors) (not shown). More specifically, the pixel transistors may include, for example, transfer transistors, selection transistors, reset transistors, and amplifier transistors.

[0065] The above-mentioned solid-state image sensor 100 can be configured as a common pixel structure. The common pixel structure is composed of a plurality of PDs, a plurality of transfer transistors, a floating diffusion portion (floating diffusion region) (charge accumulator) shared between PDs for accumulating charges generated in the PDs, and other pixel transistors shared between PDs. That is, in the common pixel structure, a plurality of photoelectric conversion pairs composed of PDs and transfer transistors are provided, and each photoelectric conversion pair shares other pixel transistors (selection transistors, reset transistors, amplification transistors, etc.). The details of the circuit (connection structure) of these pixel transistors will be described later.

[0066] (Vertical drive circuit 32)

[0067] The vertical drive circuit 32 is composed of, for example, a shift register, selects the pixel drive wiring 42, supplies a pulse for driving the solid-state image sensor 100 to the selected pixel drive wiring 42, and drives the solid-state image sensor 100 in units of rows. That is, the vertical drive circuit 32 shifts the pixel drive wiring 42 in the vertical direction ( Figure 1The solid-state image sensor 100 in the pixel array 10 is selectively scanned in units of rows sequentially (in the up-down direction in the image), and a pixel signal based on the charge generated according to the amount of received light is provided to the signal processing circuit 34 through the vertical signal line 44.

[0068] (Column signal processing circuit 34)

[0069] The column signal processing circuit 34 is arranged for each column of the solid-state image sensor 100, and performs signal processing such as noise removal for each pixel column on the pixel signal output from one column of the solid-state image sensor 100. For example, the column signal processing circuit 34 performs signal processing such as correlated double sampling (CDS) and analog-to-digital (AD) conversion to remove fixed pattern noise unique to the pixel.

[0070] (Horizontal driving circuit 36)

[0071] The horizontal drive circuit 36 ​​is formed of, for example, a shift register, sequentially outputs horizontal scanning pulses to sequentially select each of the column signal processing circuits 34 , and allows each of the column signal processing circuits 34 to output a pixel signal to a horizontal signal line 46 .

[0072] (Output circuit 38)

[0073] The output circuit 38 can perform signal processing on the pixel signals sequentially provided from each of the column signal processing circuits 34 through the horizontal signal line 46, and output the processed signals. For example, the output circuit 38 can be used as a functional unit that performs buffering, or can perform processing such as black level adjustment, column variation correction, and various digital signal processing. Buffering refers to temporarily storing pixel signals to compensate for the difference in processing speed and transmission speed when exchanging pixel signals. The input / output terminal 48 is a terminal for exchanging signals with an external device.

[0074] (Control Circuit 40)

[0075] The control circuit 40 can receive an input clock and data for indicating an operation mode, and can output data such as internal information of the solid-state image sensor 100. That is, the control circuit 40 generates a control signal and a clock signal serving as an operation reference of the vertical drive circuit 32, the column signal processing circuit 34, the horizontal drive circuit 36, etc. based on the vertical synchronization signal, the horizontal synchronization signal, and the main clock. Then, the control circuit 40 outputs the generated clock signal and control signal to the vertical drive circuit 32, the column signal processing circuit 34, the horizontal drive circuit 36, etc.

[0076] As described above, the solid-state imaging device 1 is a CMOS image sensor called a column AD type, in which a column signal processing circuit 34 for performing CDS processing and AD conversion processing is arranged for each pixel column. Figure 1 Examples are shown, and other circuits may be included, for example.

[0077] <<2. Equivalent Circuit of Solid-State Image Sensor 100>>

[0078] The overall structure of the solid-state imaging device 1 according to the present embodiment has been described above. Figure 2 and Figure 3 An equivalent circuit of the PDs 200 , 300 , and 400 included in the solid-state image sensor 100 according to the embodiment of the present invention is described. Figure 2 is an equivalent circuit diagram of the PD 200 included in the solid-state image sensor 100 according to the present embodiment, and Figure 3 is an equivalent circuit diagram of the PD 300 included in the solid-state image sensor 100 according to the present embodiment.

[0079] As in Figure 2 As schematically illustrated in the upper left portion of the figure, the stacked structure of the PD 200, which will be described in detail later, is a stacked structure including an upper electrode (common electrode) 202, a lower electrode (readout electrode) 206, and a photoelectric conversion film 204 sandwiched between the upper electrode 202 and the lower electrode 206, which are stacked above a semiconductor substrate 500 which is a silicon substrate.

[0080] like Figure 2 As shown, the upper electrode 202 is electrically connected to the selection line V OU , the selection line V OU The lower electrode 206 is electrically connected to a reset transistor TR1 for resetting the accumulated charge through wiring or the like. rst One of the drain and source of the reset transistor TR1 rst The gate of the reset transistor TR1rst is electrically connected to the reset signal line RST1, and is also electrically connected to the vertical drive circuit 32. The other of the drain and source of the reset transistor TR1rst (the side not connected to the lower electrode 206) is electrically connected to the power supply circuit V DD .

[0081] The lower electrode 206 is electrically connected to the amplifying transistor TR1 through wiring. amp The gate of the amplifier transistor TR1 amp The charge is converted into a voltage and the voltage is output as a pixel signal. Connect the lower electrode 206, the amplifier transistor TR1 amp The gate and reset transistor TR1 rstThe node FD of one of the drain and source 1 Forming the reset transistor TR1 rst The charge from the lower electrode 206 changes the node FD 1 The potential on the transistor TR1 is amp Converted into voltage. Amplifier transistor TR1 amp One of the source and drain of the transistor is electrically connected to the selection transistor TR1 through wiring. sel One of the source and drain of the selection transistor TR1 sel The pixel signal obtained by the conversion is output to the signal line VSL1 according to the selection signal. amp The other of the source and drain of the select transistor TR1 sel one side) is electrically connected to the power supply circuit VDD.

[0082] Select transistor TR1 sel The other of the source and drain (not connected to the amplifying transistor TR1 amp The select transistor TR1 is electrically connected to a signal line VSL1 that transmits the converted voltage as a pixel signal and is also electrically connected to the column signal processing circuit 34. sel The gate electrode of is electrically connected to a selection line SEL1 for selecting a row to output a pixel signal, and is also electrically connected to the above-mentioned vertical drive circuit 32.

[0083] Now refer to Figure 3 The equivalent circuit of the PD 300 provided in the semiconductor substrate 500 is described. Figure 3 As shown, the PD 300 provided in the semiconductor substrate 500 is electrically connected to the pixel transistor (amplifying transistor TR2) provided in the semiconductor substrate 500 through wiring. amp , transfer transistor TR2 trs , reset transistor TR2 rst , select transistor TR2 sel Specifically, one side of the PD 300 is electrically connected to a transfer transistor TR2 for transferring charge through wiring. trs One of the source and drain of the transmission transistor TR2 trs The other of the source and drain of the transistor TR2 (the side not connected to the PD 300) is electrically connected to the reset transistor TR2 through wiring. rst One of the source and drain of the transmission transistor TR2 trs The gate of the reset transistor TR2 is electrically connected to the transfer gate line TG2 and is also connected to the above-mentioned vertical drive circuit 32. rst The other of the source and drain of the transmission transistor TR2trs One side of the reset transistor TR2 is electrically connected to the power supply circuit VDD. rst The gate of is electrically connected to the reset line RST2, and is also connected to the above-mentioned vertical drive circuit 32.

[0084] Transfer transistor TR2 trs The other of the source and drain of the transistor TR2 (the side not connected to the PD 300) is also electrically connected through wiring to an amplifier transistor TR2 for amplifying (converting) the charge and outputting it as a pixel signal. amp The gate of the amplifier transistor TR2 amp One of the source and drain of the transistor is electrically connected to the selection transistor TR2 through wiring. sel The selection transistor outputs the pixel signal to the signal line VSL2 according to the selection signal. amp The other of the source and drain of the select transistor TR2 sel The other of the source and drain of the selection transistor TR2sel (not connected to the amplification transistor TR2 amp The selection transistor TR2 is electrically connected to the signal line VSL2 and is also electrically connected to the column signal processing circuit 34. sel The gate electrode of is electrically connected to the selection line SEL2, and is also electrically connected to the above-mentioned vertical driving circuit 32.

[0085] Similar to the PD 300, the PD 400 disposed in the semiconductor substrate 500 may also be connected to the Figure 3 The equivalent circuit in is similarly represented, and the description of the equivalent circuit of PD 400 is omitted here.

[0086] <<3. Stacked Structure of Solid-State Image Sensor 100>>

[0087] The equivalent circuits of the PDs 200, 300, and 400 included in the solid-state image sensor 100 according to the present embodiment have been described above. Figure 4 , a stacked structure of a solid-state image sensor 100 according to an embodiment of the present invention will be described. Figure 4 is a cross-sectional view of the solid-state image sensor 100 according to the present embodiment, specifically, a cross-sectional view of the solid-state image sensor 100 cut along the through-through direction of the through-electrode 600. Figure 4 , the solid-state image sensor 100 is shown such that the incident surface of the solid-state image sensor 100 on which light is incident faces upward. In the following description, the stacked structure in the solid-state image sensor 100 will be described in order from the semiconductor substrate 500 located on the lower side of the solid-state image sensor 100 toward the PD 200 located above the semiconductor substrate 500.

[0088] First, if Figure 4 As shown, in the solid-state image sensor 100 according to the present embodiment, for example, in a semiconductor region 502 having a first conductivity type (e.g., P type) of a semiconductor substrate 500 made of silicon, two semiconductor regions 510 and 512 having a second conductivity type (e.g., N type) are formed in an overlapping manner in the thickness direction (depth direction) of the semiconductor substrate 500. The semiconductor regions 510 and 512 thus formed form a PN junction to serve as two stacked PDs 300 and 400. For example, the PD 300 having the semiconductor region 510 as a charge accumulation region is a photoelectric conversion element that absorbs blue light (e.g., a wavelength of 450 nm to 495 nm) to generate charges (photoelectric conversion), and the PD 400 having the semiconductor region 512 as a charge accumulation region is a photoelectric conversion element that absorbs red light (e.g., a wavelength of 620 nm to 750 nm) to generate charges.

[0089] The wiring layer 520 is provided on a surface ( Figure 4 The wiring layer 520 includes a gate electrode 524 of a plurality of pixel transistors for reading the charges accumulated in the PDs 200, 300, and 400, a plurality of wirings 522, and an interlayer insulating film 530. For example, the gate electrode 524 and the wirings 522 may be formed of materials such as tungsten (W), aluminum (Al), and copper (Cu). The interlayer insulating film 530 may be formed of, for example, silicon oxide (SiO 2 ) or silicon nitride (SiN).

[0090] The semiconductor substrate 500 has a through electrode 600 that passes through the semiconductor substrate 500 for extracting charges generated by photoelectric conversion in the PD 200 described later to the floating diffusion 514 described later. Specifically, the conductor 602 as the central axis of the through electrode 600 can be formed of, for example, a silicon doped material such as phosphorus-doped amorphous silicon (PDAS) or a metal material such as aluminum, tungsten, titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta). A SiO2 layer is formed on the periphery of the conductor 602. 2 An insulating film 604 made of Si or SiN is formed to suppress short circuit to the semiconductor region 502. In the present embodiment, a barrier metal film (not shown) may be provided between the conductor 602 and the insulating film 604 surrounding the periphery of the conductor 602. The barrier metal film may be formed of materials such as titanium nitride (TiN), tungsten nitride (WN), Ti, tantalum nitride (TaN), and Ta.

[0091] The through-electrode 600 may be connected to the floating diffusion 514 in the semiconductor region having the second conductivity type (e.g., N-type) provided in the semiconductor substrate 500 through the wiring 522 provided in the wiring layer 520. That is, the through-electrode 600 may electrically connect the PD 200 (specifically, the lower electrode 206) to the floating diffusion 514. The floating diffusion 514 may temporarily accumulate charges generated by photoelectric conversion in the PD 200 through the through-electrode 600.

[0092] As described above, the wiring layer 520 has a plurality of gate electrodes 524 as gate electrodes of a plurality of pixel transistors for reading out the charges generated in the above-mentioned PD 200. Specifically, the electrode 524 is arranged to face the semiconductor region 502 having a first conductivity type (e.g., P type) in the semiconductor substrate 500 through the insulating film 540. In the semiconductor substrate 500, a semiconductor region 516 having a second conductivity type (e.g., N type) is also provided so as to clamp the semiconductor region 502 having the first conductivity type. The semiconductor region 516 serves as a source region and a drain region of the pixel transistor. The above-mentioned through electrode 600 can electrically connect the PD200 (specifically, the lower electrode 206) to these pixel transistors. The detailed structure of the through electrode 600 will be described later.

[0093] A fixed charge film 550 having negative fixed charges may be formed on the incident surface of the semiconductor substrate 500. The fixed charge film 550 may be made of, for example, hafnium oxide (HfO 2 ), aluminum oxide (Al 2 O 3 )、ZrO、Tantalum oxide (Ta 2 O 5 ), titanium oxide (TiO 2 ), lanthanum oxide (La 2 O 3 ), praseodymium oxide (Pr 6 O 11 ), cerium oxide (CeO 2 ), neodymium oxide (Nd 2 O 3 ), Promethium oxide (Pm 2 O 3 ), samarium oxide (Sm 2 O 3 ), europium oxide (Eu 2 O 3 ), gadolinium oxide (Gd 2 O 3 ), terbium oxide (Tb 2 O 3 ), Dysprosium oxide (Dy 2 O 3 ), holmium oxide (Ho2 O 3 ), thulium oxide (Tm 2 O 3 ), Ytterbium oxide (Yb 2 O 3 ), Lutetium oxide (Lu 2 O 3 ), yttrium oxide (Y 2 O 3 ), aluminum nitride (AlN), hafnium oxynitride (HfON), aluminum oxynitride (AlON), etc. The fixed charge film 550 may be a stacked film composed of the above different materials.

[0094] An insulating film 552 is provided on the fixed charge film 550. The insulating film 552 may be formed of, for example, a dielectric film having insulating properties, such as SiO 2 , tetraethyl orthosilicate (TEOS), silicon nitride (Si 3 N 4 ) and silicon oxynitride (SiON).

[0095] The laminated structure of the photoelectric conversion film 204 sandwiched between the upper electrode 202 and the lower electrode 206 is arranged on the insulating film 552 via the insulating film 560. The upper electrode 202, the photoelectric conversion film 204 and the lower electrode 206 constitute the PD 200 that converts light into electric charge. For example, the PD 200 is a photoelectric conversion element that absorbs green light (for example, a wavelength of 495nm to 570nm) to generate electric charge (photoelectric conversion). For example, the upper electrode 202 and the lower electrode 206 can be formed by transparent conductive films such as indium tin oxide (ITO) and indium zinc oxide (IZO). Specifically, the upper electrode 202 is shared (shared) between adjacent pixels (solid-state image sensor 100), while the lower electrode 206 is formed separately for each pixel. The lower electrode 206 is electrically connected to the above-mentioned through electrode 600 by a metal wiring 570 passing through the insulating film 560. The metal wiring 570 can be formed, for example, by metal materials such as W, Al and Cu. The insulating film 560 may be formed of, for example, an insulating material that allows light to pass therethrough, such as Al 2 O 3 、SiO 2 、Si 3 N 4 and SiON.

[0096] like Figure 4 As shown, a layer made of, for example, Si is formed on the upper electrode 202. 3 N 4 , SiON, and silicon carbide (SiC) and a planarization film 582. An on-chip lens 590 is provided on the planarization film 582. The on-chip lens 590 may be made of, for example, Si 3 N4 Or it is formed of a resin-based material such as a styrene resin, an acrylic resin, a styrene-acrylic copolymer resin, or a silicone resin.

[0097] As described above, the solid-state image sensor 100 according to the present embodiment has a stacked structure in which PDs 200, 300, and 400 corresponding to three colors are stacked. That is, the above-mentioned solid-state image sensor 100 is a vertical spectrum type solid-state image sensor that converts green light into electricity above the semiconductor substrate 500 (i.e., in the photoelectric conversion film 204 (PD 200) formed on the incident surface side of the semiconductor substrate 500), and converts blue light and red light into electricity in the PDs 300 and 400 in the semiconductor substrate 500. It can be said that the solid-state image sensor 100 according to the present embodiment is a back-illuminated CMOS solid-state image sensor having pixel transistors formed on the side opposite to the incident surface side.

[0098] The above-mentioned photoelectric conversion film 204 can be formed of an organic material (organic photoelectric conversion film) or an inorganic material (inorganic photoelectric conversion film). For example, when the photoelectric conversion film 204 is formed of an organic material, any one of the following four modes can be selected: (a) P-type organic semiconductor material; (b) N-type organic semiconductor material; (c) a stacked structure of any two of a P-type organic semiconductor material layer, an N-type organic semiconductor material layer, and a mixed layer (bulk heterostructure) of a P-type organic semiconductor material and an N-type organic semiconductor material; and (d) a mixed layer of a P-type organic semiconductor material and an N-type organic semiconductor material.

[0099] Specifically, examples of P-type organic semiconductor materials include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothienobenzothiophene derivatives, triallylamine derivatives, carbazole derivatives, chrysene derivatives, derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having a heterocyclic compound as a ligand, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

[0100] Examples of N-type organic semiconductor materials include fullerenes and fullerene derivatives. For example, fullerenes such as C60, C70, and C74 (higher order fullerenes), endohedral fullerenes, or fullerene derivatives (e.g., fullerene fluorides, phenyl-C 61-Butyric acid methyl ester (PCBM) fullerene compounds, fullerene polymers, etc.), organic semiconductors having a higher highest occupied molecular orbital (HOMO) and a lower lowest unoccupied molecular orbital (LUMO) than P-type organic semiconductors, and transparent inorganic metal oxides. More specifically, examples of N-type organic semiconductor materials include heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms, for example, organic molecules, organic metal complexes, and subphthalocyanine derivatives having pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, subporphyrin derivatives, polyphenylenevinylene derivatives, polybenzothiadiazole derivatives, polyfluorene derivatives, etc. in a part of the molecular skeleton. Examples of the group included in the fullerene derivative include a branched or cyclic alkyl group or a phenyl group; a group having a straight chain or condensed aromatic compound; a group having a halide; a partially fluorinated alkyl group; a perfluoroalkyl group; a silylalkyl group; a silylalkoxy group; an arylsilyl group; an arylsulfanyl group; an alkylsulfanil group; an arylsulfonyl group; an alkylsulfonyl group; an arylsulfide group; an alkylsulfide group; an amino group; an alkylamino group; an arylamino group; a hydroxyl group; an alkoxy group; an acylamino group; an acyloxy group; a carbonyl group; a carboxyl group; a carboxamide group; an alkoxycarbonyl group; an acyl group; a sulfonyl group; a cyano group; a nitro group; a group having a chalcogenide; a phosphine group; a phosphone group; and derivatives thereof. The thickness of the photoelectric conversion film 204 formed of an organic material may be, for example but not limited to, 1×10 -8 m to 5×10 -7 m, preferably 2.5×10 -8 m to 3×10 -7 m, more preferably 2.5×10 -8 m to 2×10 -7m. In the above description, organic semiconductor materials are classified into P-type and N-type. As used herein, P-type means that voids are easily transported, and N-type means that electrons are easily transported. That is, organic semiconductor materials are not necessarily interpreted as having voids or electrons as thermally excited main carriers like inorganic semiconductor materials.

[0101] More specifically, in order to serve as the photoelectric conversion film 204 of the PD 200 that receives green light and converts the light into electricity, the photoelectric conversion film 204 may include, for example, rhodamine-based dyes, melacyanine-based dyes, quinacridone derivatives, subphthalocyanine-based dyes (subphthalocyanine derivatives), etc.

[0102] When the photoelectric conversion film 204 is formed of an inorganic material, examples of the inorganic semiconductor material include crystalline silicon, amorphous silicon, microcrystalline silicon, crystalline selenium, amorphous selenium, and materials such as CIGS (CuInGaSe), CIS (CuInSe 2 ), CuInS 2 、CuAlS 2 、CuAlSe 2 、CuGaS 2 、CuGaSe 2 、AgAlS 2 、AgAlSe 2 、AgInS 2 、AgInSe 2 Chalcopyrite compounds such as GaAs, InP, AlGaAs, InGaP, AlGaInP and InGaAsP, and III-V compounds such as CdSe, CdS, In 2 Se 3 、In 2 S 3 、Bi 2 Se 3 、Bi 2 S 3 , ZnSe, ZnS, PbSe, and PbS. In addition, quantum dots made of the above materials can be used as the photoelectric conversion film 204.

[0103] In the present embodiment, the above-mentioned solid-state image sensor 100 is not limited to the structure of a stacked body formed by the PD 200 having the photoelectric conversion film 204 disposed over the semiconductor substrate 500 and the PDs 300 and 400 disposed in the semiconductor substrate 500. For example, in the present embodiment, the solid-state image sensor 100 may be a stacked structure including the PD 200 having the photoelectric conversion film 204 disposed over the semiconductor substrate 500 and the PD 300 disposed in the semiconductor substrate 500, that is, a stacked structure formed by two PDs 200 and 300. In the present embodiment, the solid-state image sensor 100 may be a structure having two or three PDs 200 stacked over the semiconductor substrate 500. In this case, the PD 200 may have a corresponding photoelectric conversion film 204, and the photoelectric conversion film 204 may be formed of an organic semiconductor material or may be formed of an inorganic semiconductor material. In this case, in order to serve as the photoelectric conversion film 204 of the PD 200 that receives blue light and converts the light into electricity, the photoelectric conversion film 204 may contain, for example, coumarin acid dye, tris-8-hydroxyquinoline aluminum (Alq 3 ), mesocyanine-based dyes, etc. In order to be used as the photoelectric conversion film 204 of the PD 200 that receives red light and converts the light into electricity, the photoelectric conversion film 204 may include phthalocyanine-based dyes, subphthalocyanine-based dyes (subphthalocyanine derivatives), etc.

[0104] <<4. Circumstances leading to the invention>>

[0105] Before describing the embodiments according to the present invention in detail, reference will be made to Figure 5 The circumstances that led the inventors of the present invention to come up with the embodiments of the present invention are described. Figure 5 1 is a diagram for explaining the situation leading to the creation of an embodiment of the present invention. Specifically, Figure 5 The left side of FIG. 1 schematically shows a cross section of a through electrode 800 according to a comparative example, and Figure 5 The right side of illustratively shows a cross section of a through electrode 600 according to an embodiment of the present invention. As used herein, a comparative example refers to a through electrode 800 that has been studied before the inventors of the present invention made an embodiment of the present invention.

[0106] So far, the inventors have considered providing a through electrode 600 (800) for each solid-state image sensor (pixel) 100. In this case, in order to obtain satisfactory sensitivity of the solid-state image sensor 100, it is preferable to ensure that the light incident surface of the incoming light is larger, in other words, it is preferable to ensure that the area occupied by the PDs 300 and 400 is larger. Therefore, when the through electrode 600 is provided for each solid-state image sensor 100, the through electrode 600 is preferably smaller (for example, having a smaller diameter) so as to ensure that the light incident surface of the incoming light is larger. According to the research of the inventors of the present invention, it is preferable that, for example, the diameter of the conductor 602 (802) of the through electrode 600 is about 100nm. Then, the inventors manufactured a through electrode 800 of a comparative example having the same structure as the through electrode having a small diameter as described above disclosed in the above-mentioned patent document 1, and the inventors found that it was difficult to keep the resistance value of the through electrode 800 low.

[0107] Specifically, before creating the embodiment of the present invention, the inventors of the present invention have manufactured a micro-through electrode 800 (comparative example) as shown below. Figure 5 As shown on the left side of FIG. 804 , a through hole 806 is formed, which passes through the semiconductor substrate 500 in a manner substantially perpendicular to the semiconductor substrate 500. An insulating film 804 is further formed to cover the inner wall of the through hole 806. Subsequently, a conductor 802 is deposited to fill the through hole 806 by chemical vapor deposition (CVD).

[0108] According to the research of the inventors of the present invention, when the conductor 802 is deposited to fill the through hole 806, as shown in FIG. Figure 5 As shown on the left side of , void 808 is generated in through-hole 806. It is speculated that void 808 is generated as described below. It is known that when a film is deposited by CVD, the film is deposited in a shape that conforms to the shape of the substrate. It is also known that when a film is deposited by CVD to fill through-hole 806, the film is more likely to adhere to the inner wall of through-hole 806 at the upper portion of through-hole 806, and the film tends to be deposited more easily on the upper portion of the inner wall of through-hole 806 than on the lower portion of the inner wall. Therefore, it is recognized that when conductor 802 is deposited to fill through-hole 806, conductor 802 tends to be formed in an overhanging form extending from the upper portion of the inner wall of through-hole 806. As the deposition of conductor 802 proceeds, an additional overhanging-shaped film of conductor 802 is formed on the above-mentioned overhanging-shaped film, and ultimately, the shape of the deposited conductor 802 is similar to a cover, which may presumably result in void 808 in through-hole 806. That is, in the comparative example, as Figure 5As shown on the left side of FIG. 806 , although the upper portion of the through hole 806 is closed by the conductor 802, the void 808 still remains inside the through hole 806. In other words, the through hole 806 sometimes cannot be filled with the conductor 802. In this case, since the through hole 806 fails to be filled with the conductor 802, the resistance value of the through electrode 800 increases. According to the research of the inventors of the present invention, as the through electrode 800 is reduced and the aspect ratio of the through hole 806 increases, the above phenomenon occurs more obviously.

[0109] In view of this situation, the inventors of the present invention have created an embodiment of the present invention related to the through-electrode 600 by avoiding the void 808 in the through-hole 606 to maintain a low resistance value of the through-electrode 600 , wherein the through-hole 606 may be filled with the conductor 602 .

[0110] In the comparative example, Figure 5 As shown on the left side of FIG. 8 , in the cut section orthogonal to the through-direction of the through-electrode 600, the cross-sectional area of ​​the conductor 802 of the through-electrode 800 is constant, and the shape of the conductor 802 is similar to a cylinder. In contrast, in the embodiment of the present invention, as Figure 5 As shown on the right side of , at the upper part of the through-electrode 600 (the end part on the PD 200 side), the cross-sectional area of ​​the conductor 602 in the cut section orthogonal to the through-direction of the through-electrode 600 gradually increases upward along the through-direction. That is, in the present embodiment, the upper part of the conductor 602 has a taper. More specifically, in the present embodiment, during the manufacture of the through-electrode 600 having the tapered conductor 602 as described above, the diameter of the upper part of the through-hole 606 whose inner wall is covered with the insulating film 604 increases, and the conductor 602 is deposited to fill the through-hole 606 having the increased diameter. According to the present embodiment, the diameter of the upper part of the through-hole 606 increases to allow the conductor 602 to easily reach the bottom of the through-hole 606, thereby improving the filling characteristics of the conductor 602 and avoiding the occurrence of the void 808 in the through-hole 606. Therefore, according to the present embodiment, the low resistance value of the through-electrode 600 can be maintained. The details according to the embodiment of the present invention will be described in order below.

[0111] <<5. First embodiment>>

[0112] <5.1 Detailed Structure of Through-Electrode 600>

[0113] First reference Figures 6 to 8 , describing the detailed structure of the through electrode 600 according to the first embodiment of the present invention. Figure 6 is a cross-section of the solid-state image sensor 100 according to the present embodiment ( Figure 4 ), specifically, an enlarged view of the through electrode 600 and the periphery of the through electrode 600. Figure 7 The through electrode 600 is along Figure 6Specifically, Figure 7 The upper part shows the through-electrode 600 along Figure 6 The cross-sectional view of the line A-A' cut in Figure 7 The lower part shows the through-electrode 600 along Figure 6 Cross-sectional view taken along line BB'. Figure 8 is a schematic diagram showing an upper portion of the through electrode 600 according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode 600 cut along a through direction of the through electrode 600 . Figure 8 In the figure, for ease of understanding, the fixed charge film 650 is not shown.

[0114] like Figure 6 As shown, the through-electrode 600 according to the present embodiment mainly includes a through hole 606 passing through the semiconductor substrate 500 in a manner substantially perpendicular to the semiconductor substrate 500 (in other words, along the film thickness direction of the semiconductor substrate 500), a fixed charge film 650 covering the inner wall of the through-hole 606, an insulating film 604 covering the inner wall via the fixed charge film 650, and a conductor 602 filling the through-hole 606. As described above, a barrier metal film (not shown) may be provided between the conductor 602 and the insulating film 604 surrounding the outer periphery of the conductor 602. The details of each part of the through-electrode 600 will be described in order below.

[0115] In the present embodiment, the through hole 606 is, for example, a hole in the shape of a cylinder or a truncated cone with a taper, preferably a cylindrical hole or a substantially cylindrical hole (in other words, a hole having a substantially equal opening diameter in the through direction). In the present embodiment, the through hole 606 is substantially a cylindrical hole, so that the film thickness of the insulating film 604 covering the inner wall of the through hole 606 can be more uniform. Therefore, according to the present embodiment, while ensuring the insulation between the through electrode 600 (specifically, the conductor 602) and the semiconductor substrate 500 (specifically, the semiconductor region 502), the parasitic capacitance of the through electrode 600 caused by the insulating film 604 can be reduced. Therefore, since the parasitic capacitance can be reduced, the present embodiment can avoid the noise from being accidentally transmitted to the through electrode 600 through the parasitic capacitance, thereby avoiding the deterioration of the characteristics of the solid-state image sensor 100.

[0116] In this embodiment, as described above, the fixed charge film 650 is provided to cover the inner wall and the bottom surface (lower surface) of the through hole 606. For example, similar to the above-mentioned fixed charge film 550, the fixed charge film 650 may be made of HfO 2 、Al 2 O 3 、ZrO、Ta 2 O 5 、TiO 2The fixed charge film 650 may be a laminated film composed of the above-mentioned different materials.

[0117] In the present embodiment, as described above, the insulating film 604 is provided to cover the inner wall of the through hole 606 via the fixed charge film 650. The insulating film 604 is provided to cover the periphery of the conductor 602 described later. The insulating film 604 is an insulating film for suppressing short circuit to the semiconductor substrate 500 (specifically, the semiconductor region 502), and is made of SiO 2 , SiN, etc.

[0118] In this embodiment, the conductor 602 is provided to fill the through hole 606 whose inner wall is covered with the fixed charge film 650 and the insulating film 604. In other words, Figure 6 As shown, the conductor 602 is positioned at the center of the through-electrode 600. Specifically, the conductor 602 is a substantially cylindrical electrode that passes through the central portion of the through-hole 606, and has a tapered shape at its upper portion (the end portion on the PD 200 side). The conductor 602 further passes through the bottom surface (lower surface) of the through-hole 606 to extend to the wiring 522 of the wiring layer 520. As described above, the conductor 602 may be formed of a silicon-doped material such as PDAS or a metal material such as Al, W, Ti, Co, Hf, and Ta.

[0119] More specifically, at the upper portion (the end portion on the PD 200 side) of the through-electrode 600, the cross-sectional area of ​​the conductor 602 in the cut section in the direction orthogonal to the through-direction of the through-electrode 600 gradually increases upward along the through-direction. That is, in the present embodiment, the upper side of the conductor 602 has a tapered shape.

[0120] Further references Figure 7 , conductor 602 will be described in more detail. Figure 7 The lower part of shows a plane ( Figure 6 The cutting cross section when the through electrode 600 is cut along the line BB' in FIG. Figure 7 The upper part of shows a plane perpendicular to the through direction of the through electrode 600 at the point where the insulating film 552 is passed ( Figure 6 The cutting section is the line A-A' in the figure. Figure 7 As shown in the upper and lower figures of the embodiment, in the present embodiment, the diameter of the conductor 602 increases upward. More specifically, in the present embodiment, the diameter of the conductor 602 in the cut section at the upper portion (the end portion on the PD 200 side) of the through-electrode 600 (that is, the diameter of the conductor 602 along the Figure 6 The diameter D of the conductor 602 when the line AA' cuts through the electrode 600 1 , see Figure 7) is the diameter of the conductor 602 in the cut cross section at the lower part of the through-electrode 600 (the end part on the floating diffusion part 514 side) (that is, along the Figure 6 The diameter D of the conductor 602 when the line BB' cuts through the electrode 600 2 , see Figure 7 The value is more than 1.2 times that of the lower figure in the figure.

[0121] In this embodiment, when following Figure 6 When the line BB' in FIG. 1 cuts through the electrode 600, the diameter D of the conductor 602 is 2 (See Figure 7 The lower side of the figure) is preferably 50nm to 500nm. In this embodiment, when along Figure 6 When the line AA' in FIG. 1 cuts through the electrode 600, the diameter D of the conductor 602 is 1 (See Figure 7 The upper side figure in the figure) is preferably 60nm to 600nm.

[0122] Preferably, the upper surface of the conductor 602 (the surface on the PD 200 side) is larger to ensure contact with the metal wiring 570. However, in the case where the upper surface of the conductor 602 is larger, light incidence on the PDs 300 and 400 located below relative to the upper surface of the conductor 602 is interrupted by the upper surface of the conductor 602. Therefore, in the present embodiment, it is preferred that the upper surface of the conductor 602 is smaller so as to ensure contact with the metal wiring 570. In the present embodiment, it is preferred that when the upper surface of the conductor 602 is along the Figure 6 When the line AA' in FIG. 1 cuts the through electrode 600, the upper surface of the conductor 602 is larger than the cut cross section of the conductor 602 (see Figure 7 ), and is smaller than the opening of the through hole 606 (specifically, the opening of the through hole 606 when the inner wall of the through hole is not covered with the fixed charge film 650 and the insulating film 604).

[0123] In this embodiment, if Figure 8 As shown in FIG. 1 (which shows a partially enlarged view of a cross-sectional view of the through-electrode 600 cut along the through-electrode 600's through-direction at the upper portion of the through-electrode 600 (the end portion on the PD 200 side), the slope of the outer peripheral surface of the conductor 602 of the through-electrode 600 preferably has an angle of 1° or more and 60° or less with respect to the central axis 610 of the conductor 602 extending in the through-direction. In the present embodiment, it is preferable to set the slope so as to ensure that the insulating film 604 has a film thickness capable of suppressing a short circuit to the semiconductor substrate 500 (specifically, the semiconductor region 502), and also to ensure a larger light incident surface of the PDs 300 and 400 on which light is incident.

[0124] In this embodiment, as long as the conductor 602 has a tapered shape at the upper part of the through-electrode 600 (the end on the PD 200 side), the entire through-hole 606 passing through the semiconductor substrate 500 (through the film thickness of the semiconductor substrate 500) can be tapered, and the tapered shape is not limited.

[0125] In the present embodiment, when the through-electrode 600 including the conductor 602 having the shape as described above is formed (to be described in detail later), the diameter of the upper portion of the through-hole 606 covered with the insulating film 604 is increased, and the conductor 602 is deposited to fill the increased diameter through-hole 606. According to the present embodiment, the diameter of the upper portion of the through-hole 606 is increased to allow the conductor 602 to easily reach the bottom of the through-hole 606, thereby improving the filling characteristics of the conductor 602 and avoiding the occurrence of the void 808 in the through-hole 606. Therefore, according to the present embodiment, the low resistance value of the through-electrode 600 can be maintained.

[0126] <5.2 Method of Manufacturing Solid-State Image Sensor 100>

[0127] The detailed configuration of the through electrode 600 according to the present embodiment is described above. Figures 9 to 13 A method of manufacturing the solid-state image sensor 100 including the through-electrode 600 according to the present embodiment is described. Figures 9 to 13 The present invention is used to explain the method of manufacturing the solid-state image sensor 100 according to the present embodiment and to illustrate the Figure 4 The cross-sectional views correspond to views of cross sections of the solid-state image sensor 100 in steps of the manufacturing method.

[0128] First, if Fig. 9 As shown, the semiconductor substrate 500 is processed from the light incident surface side by dry etching, for example, to form a through hole 606 a penetrating the semiconductor substrate 500 .

[0129] Then, if Fig.10 As shown, the fixed charge films 550 and 650 and the insulating films 552 and 604 are deposited to cover the inner wall and bottom surface of the through hole 606 a and the incident surface of the semiconductor substrate 500 .

[0130] Then, if Fig.11 As shown, the fixed charge film 650 and the insulating films 552 and 604 are partially removed by dry etching, for example, to form a through hole 606b that passes through the semiconductor substrate 500 and extends to the wiring 522. During this time, the insulating films 552 and 604 formed at the periphery of the upper side opening of the through hole 606b are partially removed to increase the diameter of the upper side opening of the through hole 606b.

[0131] Then, if Fig.12As shown, a conductor 602 (metal film) is deposited to fill the through hole 606b. During this time, as described below, when the through hole 606b is viewed from above, the conductor 602 may be recessed at the center of the through hole 606b.

[0132] Then, if Fig.13 As shown, the conductor 602 is partially removed, for example, by dry etching, to form a through electrode 600 .

[0133] Further, metal wiring 570 and insulating film 560 are formed. Subsequently, lower electrode 206, photoelectric conversion film 204, upper electrode 202, high refractive index layer 580, etc. are formed. Finally, planarization film 582 and on-chip lens 590 are formed. As described above, it is possible to obtain Figure 4 A solid-state image sensor 100 is shown.

[0134] The solid-state image sensor 100 according to the present embodiment can be manufactured using a method, device, and conditions for manufacturing a general semiconductor device. That is, the solid-state image sensor 100 according to the present embodiment can be manufactured using an existing method of manufacturing a semiconductor device as follows.

[0135] Examples of manufacturing methods may include physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). Examples of PVD may include vacuum deposition, electron beam (EB) deposition, sputtering processes (magnetron sputtering, RF-DC coupled bias sputtering, electron cyclotron resonance (ECR) sputtering, target-oriented sputtering, high-frequency sputtering, etc.), ion plating, laser ablation, molecular beam epitaxy (MBE), and laser transfer. Examples of chemical vapor deposition may include plasma CVD, thermal CVD, organometallic (MO) CVD, and optical CVD. Examples of other methods may include electroplating, chemical plating, spin coating; dipping; casting; microcontact printing; drop casting; printing processes such as screen printing, inkjet printing, offset printing, gravure printing and flexographic printing; stamping; spraying; coating processes such as air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, castcoater, spray coater, slit orifice coater and calendar coater. Examples of patterning may include chemical etching such as shadow mask, laser transfer, and photolithography, and physical etching using ultraviolet rays, laser, etc. In addition, examples of planarization technology may include chemical mechanical polishing (CMP), laser planarization, and reflow.

[0136] As described above, in the present embodiment, during the manufacture of the through-electrode 600 having the conductor 602, the diameter of the upper portion of the through-hole 606a having the inner wall of the cover insulating film 604 is increased, and the conductor 602 is deposited to fill the through-hole 606b having the increased diameter. According to the present embodiment, the diameter of the upper portion of the through-hole 606a is increased to allow the conductor 602 to easily reach the bottom of the through-hole 606b, thereby improving the filling characteristics of the conductor 602 and avoiding the occurrence of the void 808 in the through-hole 606b, and according to the present embodiment, the low resistance value of the through-electrode 600 can be maintained.

[0137] <5.3 Modifications>

[0138] In the solid-state image sensor 100 according to the present embodiment, the upper portion of the conductor 602 (the end portion on the PD 200 side) can be electrically connected to a wiring formed of a transparent conductor. In other words, in the present embodiment, Figure 4 The metal wiring 570 in the embodiment may be formed of a transparent conductor.

[0139] The following will refer to the above Fig.13 A method of manufacturing the solid-state image sensor 100 according to this modification example will be described. Fig.13 As shown, the conductor 602 is partially removed by dry etching, for example, and after the through electrode 600 is formed, a transparent conductor is deposited on the through electrode 600. For example, the transparent conductor is partially removed by dry etching to form a wiring structure. Thus, the wiring 570 of the solid-state image sensor 100 according to this modification can be formed. The transparent conductor can be formed of materials such as ITO and IZO.

[0140] In the present modification, the metal wiring 570 is formed of a transparent conductor to prevent light incident on the wiring 570 from being reflected and incident on the PDs 200 , 300 , and 400 unintentionally, thereby reducing the occurrence of color mixing or flare in the solid-state image sensor 100 .

[0141] <<6. Second embodiment>>

[0142] In the embodiment of the present invention, the through electrode 600 according to the first embodiment described above may be further modified. Fig.14 and Fig.15 , the through electrode 600a according to the second embodiment of the present invention will be described. Fig.14 2 is a cross-sectional view of the solid-state image sensor 100 a according to the present embodiment, specifically, a cross-sectional view of the solid-state image sensor 100 a cut along a penetration direction of the through electrode 600 a . Fig.15 is a schematic diagram of the upper portion of the through electrode 600 a according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode 600 a cut along the through direction of the through electrode 600 a. Fig.15 In the figure, for ease of understanding, the fixed charge film 650 is not shown.

[0143] like Fig.14 As shown, in the cross section of the solid-state image sensor 100a, at the upper portion of the through electrode 600a (the end portion on the PD 200 side), more specifically, at the upper end portion of the through electrode 600a (the end surface on the PD 200 side), the conductor 602a of the through electrode 600a according to the present embodiment has a central axis ( Fig.14 In the present embodiment, the branch portion 602b is bent to draw an arc from the central axis.

[0144] Specifically, as shown in FIG. 1 which is an enlarged view of the through electrode 600a according to the present embodiment. Fig.15 As shown, the upper portion of the conductor 602a (the end portion on the PD 200 side) has a shape with a radius of curvature toward the light incident surface of the semiconductor substrate 500. In other words, in the above enlarged view, the conductor 602a appears to have two branches 602b that are separated to draw an arc from the central axis 610 of the conductor 602a. In the present embodiment, the radius of curvature r of the branch 602b is preferably greater than 10nm and less than 1000nm. That is, in the same manner as in the first embodiment, it is preferred to set the radius of curvature r to ensure that the insulating film 604 has a film thickness that can suppress a short circuit to the semiconductor substrate 500 (specifically, the semiconductor region 502), and also to ensure a larger light incident surface of the PDs 300 and 400 on which light is incident.

[0145] According to the present embodiment, as compared to the above-described first embodiment, at the region of the branch portion 602b where the arc is drawn, the distance L from the open end 606c located on the upper side of the through hole 606 covering the insulating film 604 and the fixed charge film 650 (not shown) to the conductor 602a is uniform. Therefore, in the present embodiment, even if a high voltage is applied to the insulating film 604 and the fixed charge film 650, dielectric breakdown is less likely to occur at the branch portion 602b, thereby improving the withstand voltage (reliability) of the insulating film 604 and the fixed charge film 650.

[0146] In the present embodiment, in the cross section of the solid-state image sensor 100a, at the lower portion of the through electrode 600a (the end portion on the floating diffusion portion 514 side), the conductor 602a of the through electrode 600a according to the present embodiment may have two branch portions (second branch portions) separated from the central axis 610 of the conductor 602a (not shown). More specifically, in the present embodiment, for example, at the lower end portion of the through electrode 600a (the end surface on the floating diffusion portion 514 side), the conductor 602a may have two branch portions. In the present embodiment, similar to the branch portion 602b, the branch portion at the lower portion of the through electrode 600a may be bent to draw an arc from the central axis 610. In this case, the curvature radius r of the branch portion 602b at the upper portion of the through electrode 600a may be greater than the curvature radius r of the branch portion at the lower portion of the through electrode 600a.

[0147] <<7. Third embodiment>>

[0148] In the embodiment of the present invention, the through electrode 600 according to the first embodiment described above may be further modified. Fig.16 , the through electrode 600b according to the third embodiment of the present invention will be described below. Fig.16is a schematic diagram of the upper portion of the through electrode 600 b according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode 600 b cut along the through direction of the through electrode 600 b. Fig.16 In the figure, for ease of understanding, the fixed charge film 650 is not shown.

[0149] like Fig.16 As shown, in the same manner as in the aforementioned third embodiment, in the above cross section, at the upper end portion (end surface on the PD 200 side) of the through electrode 600a, the conductor 602c of the through electrode 600b according to the present embodiment has two branch portions (first branch portions) 602d separated from the central axis of the conductor 602c. In other words, the end portion of the conductor 602c on the PD 200 side according to the present embodiment has a shape that expands with a curvature radius toward the light incident surface of the semiconductor substrate 500. In addition, in the present embodiment, as Fig.16 As shown, the conductor 602c also has a recessed portion 620 located between the two branch portions 602d. That is, in this embodiment, when the through hole 606 is viewed from above, the conductor 602c is recessed at the center of the through hole 606.

[0150] In this embodiment, the recess 620 between the two branches 602 d is used to increase the contact area between the conductor 602 c and the metal wiring 570 electrically connected to the through-electrode 600 b , thereby reducing the contact resistance between the conductor 602 c and the metal wiring 570 .

[0151] <<8. Fourth embodiment>>

[0152] In the embodiment of the present invention, the PD 200 of the solid-state image sensor 100 according to the above-described first embodiment may be further modified. Fig.17 , a solid-state image sensor 100b according to a fourth embodiment of the present invention will be described below. Fig.17 is a cross-sectional view of the solid-state image sensor 100 b according to the present embodiment, specifically, a cross-sectional view of the solid-state image sensor 100 b cut along the through-electrode 600 through-electrode 600 . Fig.17 , the solid-state image sensor 100 b is illustrated such that a light incident surface of the solid-state image sensor 100 b , on which light is incident, faces upward.

[0153] In this embodiment, if Fig.17As shown, similar to the PD 200 according to the aforementioned first embodiment, the PD 200a disposed above the semiconductor substrate 500 includes an upper electrode 202, a photoelectric conversion film 204, and a lower electrode 206. In the present embodiment, the PD 200a further includes an accumulation electrode 208 facing the upper electrode 202 via the photoelectric conversion film 204 and the insulating film 560. The accumulation electrode 208 is arranged to be spaced apart from the lower electrode 206 at a certain distance, and similarly to the upper electrode 202 and the lower electrode 206, can be formed of a transparent conductor such as ITO and IZO.

[0154] In the PD 200a according to the present embodiment, wirings (not shown) are electrically connected to each of the lower electrode 206 and the accumulation electrode 208, respectively, so that a desired potential can be applied to each of the lower electrode 206 and the accumulation electrode 208 through the wirings. Therefore, in the present embodiment, the potential applied to the lower electrode 206 and the accumulation electrode 208 is controlled so that the charge generated in the photoelectric conversion film 204 can be accumulated in the photoelectric conversion film 204 or the charge can be taken out at the floating diffusion 514. In other words, the accumulation electrode 208 can be used as an electrode for charge accumulation for extracting the charge generated in the photoelectric conversion film 204 and accumulating the charge in the photoelectric conversion film 204 according to the applied potential.

[0155] In the PD 200 according to the first embodiment described above, the charge generated by the photoelectric conversion of the photoelectric conversion film 204 is directly accumulated in the floating diffusion 514 through the lower electrode 206 and the through electrode 600. Due to such a mechanism, complete depletion in the photoelectric conversion film 204 is difficult. Therefore, in the first embodiment, the kTC noise (reset noise) of the solid-state image sensor 100 is large and the random noise is worse, which may cause the quality of the captured image to be reduced. On the other hand, in the present embodiment, the accumulation electrode 208 is provided so that in the operation of the PD 200a, when the charge generated by the photoelectric conversion of each photoelectric conversion film 204 is accumulated in the photoelectric conversion film 204, the charge reaching each lower electrode 206 is discharged to the external system for resetting. In addition, in operation, after resetting, the charge accumulated in each photoelectric conversion film 204 is transferred to the corresponding lower electrode 206, and the charge transferred to the lower electrode 206 can be sequentially read out. In the operation of the PD 200a, the reset and readout operations as described above are repeatedly performed. That is, in this embodiment, when starting exposure of the solid-state image sensor 100b, complete depletion and charge removal in the floating diffusion 514 are facilitated. Therefore, this embodiment can suppress the occurrence of a phenomenon in which the quality of a captured image is reduced due to an increase in kTC noise and worse random noise of the solid-state image sensor 100b.

[0156] <<9. Fifth embodiment>>

[0157] The solid-state imaging device 1 according to the aforementioned embodiment of the present invention can generally be applied to electronic devices using imaging devices for image capturing units, such as imaging devices such as digital cameras and video cameras, portable terminal devices with image capturing functions, and copies including solid-state image sensors in image readers. The embodiments of the present invention can be further applied to robots, drones, automobiles, medical equipment (endoscopes), etc. including the above-mentioned solid-state imaging device 1. The solid-state imaging device 1 according to this embodiment can be in the form of a chip or in the form of a module with an image capturing function, which includes an imager and a signal processor or an optical system packaged together. Reference Fig.18 , an example of an electronic device 900 including an imaging device 902 having the solid-state imaging device 1 will be described as a fifth embodiment of the present invention. Fig.18 is a diagram showing an example of an electronic device 900 according to the present embodiment.

[0158] like Fig.18 As shown, the electronic device 900 includes an imaging device 902, an optical lens 910, a shutter mechanism 912, a drive circuit unit 914, and a signal processing circuit unit 916. The optical lens 910 focuses the image light (incident light) from the subject onto the imaging plane of the imaging device 902. Therefore, the signal charge is accumulated in the solid-state image sensor 100 of the solid-state imaging device 1 of the imaging device 902 for a certain period of time. The shutter mechanism 912 is opened and closed to control the light irradiation period and the light cut-off period for the imaging device 902. The drive circuit unit 914 provides a drive signal for controlling, for example, the signal transmission operation of the imaging device 902 and the shutter operation of the shutter mechanism 912 to the imaging device and the shutter mechanism. That is, the imaging device 902 performs signal transmission based on the drive signal (timing signal) provided from the drive circuit unit 914. The signal processing circuit unit 916 performs various signal processing. For example, the signal processing circuit unit 916 outputs the picture signal after signal processing to a storage medium (not shown) such as a memory or a display (not shown).

[0159] <<10. Conclusion>>

[0160] As described above, according to the embodiment and the modified example of the present invention, the resistance value of the through electrode 600 can be maintained at a low level.

[0161] In the above-described embodiment of the present invention, the solid-state image sensor 100 may be a structure in which two or three or more PDs 200 are stacked over the semiconductor substrate 500. In this case, for example, the through-electrode 600 according to the present embodiment may be used as a through-electrode for transferring charges generated in the PD 200 stacked on the upper side among the two PDs 200 stacked over the semiconductor substrate 500 to the floating diffusion 514 provided in the semiconductor substrate 500.

[0162] In the above-described embodiment of the present invention, the solid-state image sensor 100 in which the first conductivity type is P type, the second conductivity type is N type, and electrons are used as signal charges has been described. However, the embodiment of the present invention is not limited to such an example. For example, the present embodiment can be applied to the solid-state image sensor 100 in which the first conductivity type is N type, the second conductivity type is P type, and holes are signal charges.

[0163] In the above-mentioned embodiments of the present invention, the semiconductor substrate 500 is not necessarily a silicon substrate, and may be any other substrate (eg, a silicon-on-insulator (SOI) substrate or a SiGe substrate). The above-mentioned semiconductor substrate 500 may have a semiconductor structure formed on these various substrates, etc.

[0164] The solid-state image sensor 100 according to the embodiment of the present invention is not limited to a solid-state image sensor that detects the distribution of the incident light amount of visible light to capture an image. For example, the present embodiment can be applied to a solid-state image sensor that captures the distribution of the incident amount of infrared rays, X-rays, particles, etc. as an image and a solid-state image memory (physical quantity distribution detection device) that detects the distribution of any other physical quantity such as pressure and capacitance as an image, such as a fingerprint detection sensor.

[0165] <11. Application in endoscopic surgery system>>

[0166] The technology according to the present invention (the present technology) can be applied to various products. For example, the technology according to the present invention can be applied to an endoscopic surgery system.

[0167] Fig.19 : is a diagram showing an overall configuration example of an endoscopic surgery system to which the technology according to the present invention (the present technology) can be applied.

[0168] Fig.19 The following situation is shown: an operator (doctor) 11131 performs surgery on a patient 11132 on a bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 includes an endoscope 11100, other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy treatment tool 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 for carrying various endoscopic surgery devices.

[0169] The endoscope 11100 includes a lens barrel 11101 and a camera head 11102 connected to the base end of the lens barrel 11101, and a region of a predetermined length starting from the tip end of the lens barrel 11101 is inserted into a body cavity of a patient 11132. In the example shown in the drawings, the endoscope 11100 is a rigid borescope having a rigid lens barrel 11101. However, the endoscope 11100 may also be configured as a flexible borescope having a flexible lens barrel 11101.

[0170] The tip of the lens barrel 11101 has an opening, and the objective lens is adapted in the opening. The light source device 11203 is connected to the endoscope 11100. The light generated by the light source device 11203 is transmitted to the tip of the lens barrel 11101 through the light guide extending inside the lens barrel 11101, and illuminates the observation target in the body cavity of the patient 11132 through the objective lens. The endoscope 11100 can be a forward-looking endoscope, or can be a forward-oblique-looking endoscope or a side-looking endoscope.

[0171] An optical system and an image sensor are provided inside the camera head 11102, so that reflected light (observation light) from an observation target is collected on the image sensor through the optical system. The observation light is converted into electricity by the image sensor to generate an electrical signal corresponding to the observation light, that is, an image signal corresponding to the observation image. The image signal is transmitted to a camera control unit (CCU) 11201 as raw data.

[0172] The CCU 11201 is configured with a central processing unit (CPU), a graphics processing unit (GPU), etc. to centrally control the operations of the endoscope 11100 and the display device 11202. The CCU 11201 receives an image signal from the camera head 11102 and performs various image processing such as development processing (demosaicing) on ​​the image signal to display an image based on the image signal.

[0173] Under the control of the CCU 11201 , the display device 11202 displays an image based on an image signal on which image processing has been performed by the CCU 11201 .

[0174] The light source device 11203 is configured with a light source such as a light emitting diode (LED), and provides irradiation light to the endoscope 11100 when imaging a surgical site or the like.

[0175] The input device 11204 is an input interface for the endoscopic surgery system 11000. The user can input various types of information or instructions in the endoscopic surgery system 11000 through the input device 11204. For example, the user can input an instruction for changing the imaging conditions (type of irradiation light, magnification factor, focal length, etc.) of the endoscope 11100.

[0176] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for tissue cauterization, cutting, and blood vessel sealing. The gas insufflator 11206 injects gas into the body cavity of the patient 11132 through the gas insufflation tube 11111 to expand the body cavity, thereby ensuring the field of view of the endoscope 11100 and ensuring the working space of the operator. The recorder 11207 is a device capable of recording various information related to the operation. The printer 11208 is a device capable of printing various information related to the operation in various forms such as text, images, and charts.

[0177] Note that, for example, the light source device 11203 for providing irradiation light to the endoscope 11100 when imaging a surgical site may be configured with a white light source such as an LED, a laser light source, or a combination thereof. When the white light source is configured with a combination of RGB laser light sources, the output power and output timing of each color (each wavelength) can be accurately controlled, and thus the white balance of the captured image can be adjusted in the light source device 11203. In this case, by irradiating the observation target with a laser beam from each of the RGB laser light sources in a time-division manner and controlling the drive of the image sensor in the camera head 11102 in synchronization with the emission timing, images corresponding to each of the RGB can be captured in a time-division manner. According to this method, a color image can be acquired even if the image sensor has no color filter.

[0178] In addition, the driving of the light source device 11203 can be controlled so that the intensity of the output light is changed every predetermined time. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity so as to acquire images in a time-division manner and synthesize the images, a high dynamic range image without underexposed shadows and overexposed highlights is generated.

[0179] The light source device 11203 can be configured to provide light in a predetermined wavelength band corresponding to specific light observation. In specific light observation, for example, narrowband imaging is performed, in which the wavelength dependence of light absorption in body tissue is utilized and a narrowband light compared to the irradiation light (i.e., white light) during normal observation is applied to capture images of predetermined tissues such as blood vessels in the outermost surface of the mucosa. Alternatively, in specific light observation, fluorescence observation can be performed, in which an image is obtained by fluorescence generated by irradiation of excitation light. In fluorescence observation, for example, a fluorescence image can be obtained by applying excitation light to body tissue and observing fluorescence from the body tissue (autofluorescence imaging), or locally injecting a reagent such as indocyanine green (ICG) into the body tissue and applying excitation light corresponding to the fluorescence wavelength of the reagent to the body tissue. The light source device 11203 can be configured to provide narrowband light and / or excitation light corresponding to such specific light observation.

[0180] Fig. 20It is shown Fig.19 A block diagram of an example of the functional configuration of the camera head 11102 and the CCU 11201 shown.

[0181] The camera head 11102 includes a lens unit 11401, an imager 11402, a driver 11403, a communication module 11404, and a camera head controller 11405. The CCU 11201 includes a communication module 11411, an image processor 11412, and a controller 11413. The camera head 11102 and the CCU 11201 are connected via a transmission cable 11400 to communicate with each other.

[0182] The lens unit 11401 is an optical system provided at a portion connected to the lens barrel 11101. Observation light acquired from the tip of the lens barrel 11101 propagates to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is configured with a combination of a plurality of lenses including a zoom lens and a focus lens.

[0183] The imager 11402 is configured with an image sensor. The imager 11402 may be configured with one image sensor (referred to as a single sensor type) or multiple image sensors (referred to as a multi-sensor type). When the imager 11402 includes a multi-sensor structure, for example, image signals corresponding to R, G, and B are generated by each image sensor, and a color image may be generated by synthesizing these image signals. Alternatively, the imager 11402 may also have a pair of image sensors for acquiring a right-eye image signal and a left-eye image signal corresponding to a three-dimensional (3D) display. The 3D display enables the operator 11131 to more accurately perceive the depth of body tissue at the surgical site. When the imager 11402 is a multi-sensor structure, multiple rows of lens units 11401 may be arranged in a manner corresponding to each image sensor.

[0184] The imager 11402 does not have to be disposed in the camera head 11102. For example, the imager 11402 may be disposed inside the lens barrel 11101 immediately after the objective lens.

[0185] The driver 11403 is configured with 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 controller 11405. Therefore, the magnification and focus of the image captured by the imager 11402 can be appropriately adjusted.

[0186] The communication module 11404 is configured with a communication device for transmitting / receiving various information to / from the CCU 11201. The communication module 11404 transmits the image signal obtained from the imager 11402 to the CCU 11201 as raw data through the transmission cable 11400.

[0187] The communication module 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201, and provides the received signal to the camera head controller 11405. For example, the control signal includes information on imaging conditions, such as information for specifying a frame rate for capturing an image, information for specifying an exposure value at the time of imaging, and / or information for specifying a magnification and a focus for capturing an image.

[0188] Imaging conditions such as frame rate, exposure value, magnification, and focus may be appropriately specified by the user or automatically set based on the acquired image signal by the controller 11413 of the CCU 11201. In the latter case, the endoscope 11100 is equipped with an automatic exposure (AE) function, an automatic focus (AF) function, and an automatic white balance (AWB) function.

[0189] The camera head controller 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 through the communication module 11404 .

[0190] The communication module 11411 is configured with a communication device for transmitting / receiving various types of information to / from the camera head 11102. The communication module 11411 receives an image signal transmitted from the camera head 11102 through the transmission cable 11400.

[0191] The communication module 11411 transmits a control signal for controlling the driving of the camera head 11102 to the camera head 11102. The image signal and the control signal may be transmitted through electrical communication or optical communication.

[0192] The image processor 11412 performs various image processing on the image signal transmitted from the camera head 11102 as raw data.

[0193] The controller 11413 performs various controls on imaging of a surgical site, etc., performed by the endoscope 11100 and display of a captured image obtained by the imaging of the surgical site, etc. For example, the controller 11413 generates a control signal for controlling the driving of the camera head 11102 .

[0194] The controller 11413 displays a captured image for visualizing a surgical site, etc., on the display device 11202 based on an image signal that has been image-processed by the image processor 11412. During this time, the controller 11413 can identify various objects in the captured image by using various image recognition technologies. For example, the controller 11413 can detect the shape, color, etc. of the edge of an object included in the captured image to identify surgical tools such as forceps, a specific living body position, bleeding, fog when using the energy treatment tool 11112, etc. When the captured image is displayed on the display device 11202, the controller 11413 can use the recognition result to superimpose various surgical auxiliary information on the image of the surgical site. The surgical auxiliary information superimposed and displayed to the operator 11131 can reduce the burden of the operator 11131 or ensure that the operator 11131 performs the operation.

[0195] The transmission cable 11400 for connecting the camera head 11102 and the CCU 11201 is an electric signal cable corresponding to electric signal communication, an optical fiber corresponding to optical communication, or a composite cable thereof.

[0196] In the example shown in the drawing, wired communication is performed using a transmission cable 11400. However, communication between the camera head 11102 and the CCU 11201 may be wireless.

[0197] An example of an endoscopic surgical system to which the technology according to the present invention can be applied has been described above. For example, the technology according to the present invention can be applied to the endoscope 11100, the imager 11402 in the camera head 11102, and the image processor 11412 of the CCU 11201 in the above-mentioned configuration. For example, Figure 1 The solid-state imaging device 1 shown can be applied to an endoscope 11100, an imager 11402, an image processor 11412, etc. When the technology according to the present invention is applied to the endoscope 11100, the imager 11402, the image processor 11412, etc., a sharper surgical site image can be obtained to ensure that the operator checks the surgical site.

[0198] Although an endoscopic surgical system is described here by way of example, the technology according to the present invention can be applied to, for example, a microscope surgical system.

[0199] <<12. Application on movable objects>>

[0200] The technology according to the present invention (the present technology) can be applied to various products. For example, the technology according to the present invention can be implemented in the form of a device installed on any type of movable body, such as a car, an electric car, a hybrid electric car, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, and a robot.

[0201] Fig.21 : is a block diagram showing an example of the overall configuration of a vehicle control system as an example of a movable body control system to which the technology according to the present invention is applicable.

[0202] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. Fig. 22 In the example shown, the vehicle control system 12000 includes a drive control unit 12010, a vehicle body control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and a central control unit 12050. In addition, a microcomputer 12051, an audio image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown as the functional configuration of the central control unit 12050.

[0203] The drive control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various types of programs. For example, the drive control unit 12010 serves as a control device for a drive force generating device such as an internal combustion engine or a drive motor for generating a drive force for the vehicle, a drive force transmitting mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a brake device for generating a braking force for the vehicle.

[0204] The body control unit 12020 controls the operation of various devices provided on the vehicle body according to various types of programs. For example, the body control unit 12020 is used as a control device for a keyless entry system, a smart key system, a power window device, or various lights such as a headlight, a reverse light, a brake light, a turn signal, or a fog light. In this case, the body control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body control unit 12020 receives input of these radio waves or signals and controls the door lock device, power window device, lights, etc. of the vehicle.

[0205] The vehicle exterior information detection unit 12030 detects exterior information of a vehicle equipped with the vehicle control system 12000. For example, an imager 12031 is connected to the vehicle exterior information detection unit 12030. The vehicle exterior information detection unit 12030 causes the imager 12031 to capture an image of the exterior of the vehicle and receive the captured image. Based on the received image, the vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing on a person, a vehicle, an obstacle, a sign, or a character on a road surface.

[0206] Imager 12031 is an optical sensor that receives light and outputs an electrical signal depending on the amount of light received. Imager 12031 can output the electrical signal as an image or as ranging information. The light received by imager 12031 may be visible light, or may be invisible light such as infrared rays.

[0207] The in-vehicle information detection unit 12040 detects the interior information of the vehicle. For example, the in-vehicle information detection unit 12040 is connected to a driver state detector 12041 for detecting the driver's state. The driver state detector 12041 includes, for example, a camera that captures an image of the driver, and based on the detection information input from the driver state detector 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or driving concentration level, or can determine whether the driver has fallen asleep.

[0208] Based on the internal information or external information of the vehicle obtained by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, the microcomputer 12051 can calculate the control target value of the driving force generation device, the steering mechanism or the braking device, and can output the control command to the driving system controller 12010. For example, the microcomputer 12051 can perform cooperative control for operating an advanced driver assistance system (ADAS), including vehicle collision avoidance or vehicle collision shock reduction, following driving based on vehicle-to-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, and vehicle lane departure warning.

[0209] The microcomputer 12051 can perform collaborative control for, for example, autonomous driving, wherein a driving force generating device, a steering mechanism or a braking device is controlled based on internal information or external information of the vehicle obtained by an external information detection unit 12030 or an internal information detection unit 12040 to enable automatic driving without depending on the operation of the driver.

[0210] The microcomputer 12051 may output a control command to the body control unit 12020 based on the external information of the vehicle obtained by the vehicle exterior information detection unit 12030. For example, the microcomputer 12051 may perform cooperative control for preventing glare by, for example, controlling the headlights to change the high beam to the low beam according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030.

[0211] The audio image output unit 12052 transmits an output signal of at least one of sound and image to an output device capable of visually or auditorily notifying the passenger of the vehicle or the outside of the vehicle of information. Fig.21In the example of FIG. 1 , an audio speaker 12061, a display 12062, and a dashboard 12063 are shown as examples of output devices. The display 12062 may, for example, include at least one of an in-vehicle display and a head-up display.

[0212] Fig. 22 is a diagram showing an example of the installation position of the imager 12031.

[0213] exist Fig. 22 , vehicle 12100 has imagers 12101 , 12102 , 12103 , 12104 , and 12105 as imager 12031 .

[0214] For example, imagers 12101, 12102, 12103, 12104, and 12105 are disposed at locations such as the front nose, rearview mirror, rear bumper, and rear door of the vehicle 12100, and the upper portion of the windshield inside the vehicle. The imager 12101 disposed at the front nose and the imager 12105 disposed at the upper portion of the windshield inside the vehicle mainly obtain images in front of the vehicle 12100. The imagers 12102 and 12103 disposed at the rearview mirror mainly obtain images on both sides of the vehicle 12100. The imager 12104 disposed at the rear bumper or rear door mainly obtains images behind the vehicle 12100. For example, the front images obtained by the imagers 12101 and 12105 are mainly used to detect front vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0215] Fig. 22 An example of the imaging ranges of the imagers 12101 to 12104 is shown. The imaging range 12111 represents the imaging range of the imager 12101 disposed at the front nose, the imaging ranges 12112 and 12113 respectively represent the imaging ranges of the imagers 12102 and 12103 disposed at the rearview mirror, and the imaging range 12114 represents the imaging range of the imager 12104 disposed at the rear bumper or the rear door. For example, a bird's-eye view image of the vehicle 12100 as viewed from above is obtained by superimposing the image data captured by the imagers 12101 to 12104.

[0216] At least one of the imagers 12101 to 12104 may have a function of obtaining distance information. For example, at least one of the imagers 12101 to 12104 may be a stereo camera including an image sensor, or may be an image sensor having pixels for phase difference detection.

[0217] For example, based on the distance information obtained from the imagers 12101 to 12104, the microcomputer 12051 can determine the distance to the three-dimensional object within the imaging range 12111 to 12114 and the time change of the distance (relative speed relative to the vehicle 12100) to specifically extract the three-dimensional object closest to the vehicle 12100 that exists on the driving path and travels at a predetermined speed (e.g., equal to or greater than 0 km / h) in the substantially same direction as the vehicle 12100 as the front vehicle. In addition, the microcomputer 12051 can pre-set the vehicle-to-vehicle distance to be maintained in front of the front vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start driving control). In this way, cooperative control for autonomous driving can be performed, in which the vehicle automatically drives without depending on the driver's operation.

[0218] For example, based on the distance information obtained from the imagers 12101 to 12104, the microcomputer 12051 can classify the three-dimensional object data on the three-dimensional object into two-wheeled vehicles, standard vehicles, heavy vehicles, pedestrians, utility poles, or any other three-dimensional objects, and use the data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that the driver of the vehicle 12100 can visually identify and obstacles that the driver cannot visually identify. Then, the microcomputer 12051 determines a collision risk indicating a dangerous level of collision with each obstacle, and when the collision risk is equal to or higher than a preset value and there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver via the audio speaker 12061 or the display 12062, or performs forced deceleration or anti-collision steering through the drive control unit 12010, thereby realizing driving assistance for avoiding collision.

[0219] At least one of the imagers 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 may identify a pedestrian by determining whether there is a pedestrian in the captured images of the imagers 12101 to 12104. This recognition of pedestrians is performed, for example, by the following process: a process of extracting feature points in the captured images of the imagers 12101 to 12104 as infrared cameras; and a process of performing pattern matching processing on a series of feature points representing the outline of an object to determine whether it is a pedestrian. When the microcomputer 12051 determines that there is a pedestrian in the captured images of the imagers 12101 to 12104 and identifies the pedestrian, the audio image output module 12052 controls the display 12062 so that a square outline is superimposed and displayed on the identified pedestrian for emphasis. The audio image output module 12052 may also control the display 12062 so that an icon or the like for representing a pedestrian is displayed at a desired position.

[0220] An example of a vehicle control system to which the technology according to the present invention is applied has been described below. The technology according to the present invention can be applied to the imager 12031 and the like in the above-mentioned configuration. For example, Figure 1 The solid-state imaging device 1 shown can be applied to the imager 12031. When the technology according to the present invention is applied to the imager 12031, a more visible captured image can be obtained to reduce the fatigue of the driver.

[0221] <<13. Additional Explanation>>

[0222] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the technical scope of the present invention is not limited to these embodiments. It is obvious that a person with ordinary knowledge in the technical field of the present invention will make various changes and modifications without departing from the technical ideas recorded in the claims, and it should be understood that these changes and modifications naturally belong to the technical scope of the present invention.

[0223] The effects described in this specification are merely explanatory or illustrative and are not intended to be limiting. The technology according to the present invention can achieve other effects that are obvious to those skilled in the art from the disclosure in this specification in addition to or instead of the above effects.

[0224] The following configurations may fall within the technical scope of the present invention.

[0225] (1) A solid-state image sensor comprising:

[0226] Semiconductor substrates;

[0227] A charge accumulator disposed in the semiconductor substrate and configured to accumulate charges;

[0228] A photoelectric converter disposed above the semiconductor substrate, for converting light into electric charges; and

[0229] a through electrode that passes through the semiconductor substrate and electrically connects the charge accumulator and the photoelectric converter,

[0230] At the end of the through-electrode on the photoelectric converter side, a conductor located at the center of the through-electrode has a cross-sectional area in a cut section orthogonal to the through-direction of the through-electrode that gradually increases toward the photoelectric converter along the through-direction.

[0231] (2) The solid-state image sensor according to (1), wherein the through-electrode electrically connects the photoelectric converter and at least one pixel transistor provided in the semiconductor substrate.

[0232] (3) The solid-state image sensor according to (1) or (2), further including an insulating film covering the periphery of the conductor of the through electrode.

[0233] (4) A solid-state image sensor according to any one of (1) to (3), wherein the slope of the outer peripheral surface of the conductor at the end portion on the side of the photoelectric converter has an angle of not less than 1° and not more than 60° relative to the central axis of the conductor extending along the through-direction.

[0234] (5) The solid-state image sensor according to any one of (1) to (3), wherein the conductor has a substantially cylindrical shape.

[0235] (6) The solid-state image sensor according to (5), wherein a diameter of the conductor on the photoelectric converter side in the cut section is 1.2 times or more the diameter of the conductor on the charge collector side in the cut section.

[0236] (7) The solid-state image sensor according to any one of (1) to (3), wherein

[0237] In a cross section of the through electrode cut along the through direction,

[0238] The end portion of the conductor on the photoelectric converter side has two first branch portions whose central axes are separated from each other.

[0239] (8) The solid-state image sensor according to (7), wherein the end portion of the conductor on the photoelectric converter side further has a recessed portion between the two first branch portions.

[0240] (9) The solid-state image sensor according to (7) or (8), wherein each of the first branch portions is bent to draw an arc from the central axis.

[0241] (10) The solid-state image sensor according to (9), wherein each of the first branch portions is curved with a curvature radius of 10 nm or more and 100 nm or less.

[0242] (11) The solid-state image sensor according to (7), wherein, in a cross section of the through-electrode cut along the through-direction, the end of the conductor on the charge collector side has two second branch portions separated from the central axis.

[0243] (12) The solid-state image sensor according to (11), wherein each of the first branch portions and each of the second branch portions are bent to draw an arc from the central axis.

[0244] (13) The solid-state image sensor according to (12), wherein a radius of curvature of the first branch portion is larger than a radius of curvature of the second branch portion.

[0245] (14) The solid-state image sensor according to any one of (1) to (13), wherein the end portion of the conductor on the photoelectric converter side is electrically connected to a wiring composed of a transparent conductor.

[0246] (15) The solid-state image sensor according to any one of (1) to (14), wherein the photoelectric converter includes:

[0247] a common electrode shared between the solid-state image sensors adjacent to each other;

[0248] a readout electrode electrically connected to the through-electrode; and

[0249] The photoelectric conversion film sandwiched between the common electrode and the readout electrode is configured to convert light into electric charges.

[0250] (16) The solid-state image sensor according to (15), wherein the photoelectric conversion film includes an organic material.

[0251] (17) The solid-state image sensor according to (15) or (16), wherein the photoelectric converter further includes an accumulation electrode that faces the common electrode via the photoelectric conversion film and an insulating film.

[0252] (18) The solid-state image sensor according to any one of (1) to (17), further including another photoelectric converter that is provided in the semiconductor substrate and converts light into electric charge.

[0253] (19) A solid-state imaging device comprising a plurality of solid-state image sensors arranged in a matrix, each of the solid-state image sensors comprising:

[0254] Semiconductor substrates;

[0255] A charge accumulator disposed in the semiconductor substrate and configured to accumulate charges;

[0256] A photoelectric converter disposed above the semiconductor substrate, for converting light into electric charges; and

[0257] a through electrode that passes through the semiconductor substrate and electrically connects the charge accumulator and the photoelectric converter,

[0258] At the end of the through-electrode on the photoelectric converter side, a conductor located at the center of the through-electrode has a cross-sectional area in a cut section orthogonal to the through-direction of the through-electrode that gradually increases toward the photoelectric converter along the through-direction.

[0259] (20) A method for manufacturing a solid-state image sensor, the image sensor comprising:

[0260] Semiconductor substrates;

[0261] A charge accumulator disposed in the semiconductor substrate and configured to accumulate charges;

[0262] A photoelectric converter disposed above the semiconductor substrate, for converting light into electric charges; and

[0263] a through electrode that passes through the semiconductor substrate and electrically connects the charge accumulator and the photoelectric converter,

[0264] wherein, at the end of the through electrode on the photoelectric converter side, the cross-sectional area of ​​the conductor located at the center of the through electrode in a cut section orthogonal to the through direction of the through electrode gradually increases toward the photoelectric converter along the through direction,

[0265] The method comprises:

[0266] forming a through hole through the semiconductor substrate;

[0267] depositing an insulating film to cover the inner wall of the through hole;

[0268] etching the insulating film at an end portion of the through hole on the photoelectric converter side; and

[0269] The through-holes are filled with a metal film.

[0270] Reference numerals list

[0271] 1 Solid-state imaging devices

[0272] 10-Pixel Array

[0273] 32 Vertical drive circuit

[0274] 34 columns of signal processing circuits

[0275] 36 Horizontal drive circuit

[0276] 38 Output Circuit

[0277] 40 Control circuit

[0278] 42 Pixel drive wiring

[0279] 44 vertical signal line

[0280] 46 horizontal signal lines

[0281] 48 Input / Output Terminals

[0282] 100, 100a, 100b Solid-state image sensor

[0283] 200a, 200a, 300, 400 Photoelectric conversion element

[0284] 202 Upper electrode

[0285] 204 Photoelectric conversion film

[0286] 206 Lower electrode

[0287] 208 Accumulation Electrode

[0288] 500 Semiconductor Substrate

[0289] 502, 510, 512, 516 semiconductor area

[0290] 514 Floating Diffuser

[0291] 520 Wiring layer

[0292] 522 Wiring

[0293] 524 Gate electrode

[0294] 530 Interlayer insulation film

[0295] 540, 552, 560, 604, 804 Insulation film

[0296] 550, 650 fixed charge membrane

[0297] 570 Metal wiring

[0298] 580 High refractive index layer

[0299] 582 Flattening Film

[0300] 590 On-chip lens

[0301] 600, 600a, 600b, 800 through-electrode

[0302] 602, 602a, 602c, 802 conductors

[0303] 602b, 602d Branch

[0304] 606, 606a, 606b, 806 through hole

[0305] 606c Open end

[0306] 610 Center Axis

[0307] 620 recess

[0308] 808 Gap

[0309] 900 Electronic equipment

[0310] 902 Imaging Devices

[0311] 910 Optical Lens

[0312] 912 Shutter mechanism

[0313] 914 drive circuit unit

[0314] 916 Signal Processing Circuit Unit

Claims

1. A solid-state image sensor, comprising: Semiconductor substrates; A charge accumulator disposed in the semiconductor substrate and configured to accumulate charges; A photoelectric converter disposed above the semiconductor substrate, for converting light into electric charges; and a through electrode that passes through the semiconductor substrate and electrically connects the charge accumulator and the photoelectric converter, wherein, at the end of the through electrode on the photoelectric converter side, the cross-sectional area of ​​the conductor located at the center of the through electrode in a cut section orthogonal to the through direction of the through electrode gradually increases toward the photoelectric converter along the through direction, Wherein, in the cross section of the through electrode cut along the through direction, The end portion of the conductor on the photoelectric converter side has two first branch portions separated from a central axis of the conductor.

2. The solid-state image sensor according to claim 1, wherein: The through-electrode electrically connects the photoelectric converter and one or more pixel transistors provided in the semiconductor substrate. 3 . The solid-state image sensor according to claim 1 , further comprising an insulating film covering a periphery of the conductor of the through-electrode.

4. The solid-state image sensor according to claim 1, wherein: The slope of the outer peripheral surface of the conductor at the end portion on the photoelectric converter side has an angle of not less than 1° and not more than 60° with respect to a central axis of the conductor extending in the penetrating direction.

5. The solid-state image sensor according to claim 1, wherein: The conductor has a substantially cylindrical shape.

6. The solid-state image sensor according to claim 5, wherein: The diameter of the conductor on the photoelectric converter side in the cut cross section is 1.2 times or more the diameter of the conductor on the charge accumulator side in the cut cross section.

7. The solid-state image sensor according to claim 1, wherein: The end portion of the conductor on the photoelectric converter side further has a recessed portion located between the two first branch portions.

8. The solid-state image sensor according to claim 1, wherein: Each of the first branch portions is bent to describe an arc from the central axis.

9. The solid-state image sensor according to claim 8, wherein: Each of the first branch portions is bent with a curvature radius of not less than 10 nm and not more than 1000 nm.

10. The solid-state image sensor according to claim 1, wherein: In a cross section of the through-electrode cut along the through-direction, an end portion of the conductor on the charge accumulator side has two second branch portions separated from the central axis.

11. The solid-state image sensor according to claim 10, wherein: Each of the first branch portions and each of the second branch portions are bent to draw an arc from the central axis.

12. The solid-state image sensor according to claim 11, wherein: A curvature radius of the first branch portion is greater than a curvature radius of the second branch portion.

13. The solid-state image sensor according to any one of claims 1 to 12, wherein: The end portion of the conductor on the photoelectric converter side is electrically connected to a wiring formed of a transparent conductor.

14. The solid-state image sensor according to any one of claims 1 to 12, wherein: The photoelectric converter comprises: a common electrode shared between the solid-state image sensors adjacent to each other; a readout electrode electrically connected to the through-electrode; and A photoelectric conversion film sandwiched between the common electrode and the readout electrode converts light into electric charges.

15. The solid-state image sensor according to claim 14, wherein: The photoelectric conversion film is composed of an organic material.

16. The solid-state image sensor according to claim 14, wherein: The photoelectric converter further includes an accumulation electrode facing the common electrode via the photoelectric conversion film and an insulating film. 17 . The solid-state image sensor according to claim 1 , further comprising another photoelectric converter which is provided in the semiconductor substrate and converts light into electric charges.

18. A solid-state imaging device comprising a plurality of solid-state image sensors according to any one of claims 1 to 17 arranged in a matrix.

19. A method for manufacturing a solid-state image sensor according to any one of claims 1 to 17, The method comprises: forming a through hole through the semiconductor substrate; depositing an insulating film to cover the inner wall of the through hole; etching the insulating film at an end portion of the through hole on the photoelectric converter side; and The through-holes are filled with a metal film.

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