Patent Description:
In solid-state image sensors such as charge-coupled device (CCD) image sensors and complementary metal-oxide-semiconductor (CMOS) image sensors, provision of a through electrode for each pixel (solid-state image sensor) has been contemplated. An example of such solid-state image sensors is a solid-state image sensor disclosed in Patent Literature <NUM> below. Further solid-state image sensors are known from <CIT> and <CIT>.

Unfortunately, in the through electrode disclosed in Patent Literature <NUM> above, it is difficult to keep the resistance value of the through electrode low.

In view of such a situation, the present disclosure proposes a new and improved solid-state image sensor having a through electrode with a resistance value kept low, a solid-state imaging device, and a method of manufacturing a solid-state image sensor.

According to the present invention, a solid-state image sensor is provided as defined in claim <NUM>.

Moreover, according to the present invention, a solid-state imaging device is provided that includes a plurality of solid-state image sensors arranged in a matrix as recited in claim <NUM>.

Moreover, according to the present invention, a method of manufacturing a solid-state image sensor is provided as defined in claim <NUM>.

As described above, the present disclosure can keep the resistance value of the through electrode low.

The effect above is not necessarily limitative, and any effects shown in the present description or other effects that may be construed from the present description may be achieved in addition to or instead of the effect above.

Preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present description and drawings, the constituent elements having substantially the same functional configuration are denoted by the same reference sign and an overlapping description is omitted.

In the present description and drawings, similar constituent elements in different embodiments may be denoted by the same reference sign followed by different alphabets so that they are distinguished from each other. However, when the similar constituent elements need not be distinguished from each other, they are denoted only by the same reference sign.

The drawings referred to in the following description are intended for description of embodiments of the present disclosure and to facilitate understanding thereof, and the shape, dimensions, and ratio illustrated in the drawings may be different from the actual ones for ease of understanding. The solid-state image sensor and the solid-state imaging device illustrated in the drawings can be modified as appropriate in consideration of the following description and known techniques. The up-down direction of a stack structure of the solid-state image sensor in a description using a cross-sectional view of the solid-state image sensor corresponds to a relative direction when a light incident surface on which light enters the solid-state image sensor is the upper side, and may differ from the up-down direction in accordance with the actual acceleration of gravity.

A specific size or shape in the following description is not intended to mean only the same value as a mathematically defined numerical value or a geometrically defined shape but includes differences to a degree industrially acceptable in the manufacturing process of solid-state image sensors or shapes similar to the specific shape. For example, in the following description, the expression "cylindrical shape" or "substantially cylindrical shape" is not limited to a cylinder having a top face and a bottom face shaped in a perfect circle but also means a cylinder having a top face and a bottom face having a shape similar to a perfect circle, such as an oval shape.

In the following description of a circuit configuration, "electrically connect" means connecting a plurality of elements to each other such that electrical continuity is established, unless otherwise specified. In addition, "electrically connect" in the following description not only includes directly and electrically connecting a plurality of elements but also includes indirectly and electrically connecting the elements through another element.

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

The description will be given in the following order.

First of all, prior to a description of embodiments according to the present disclosure, referring to <FIG>, an overall configuration of a solid-state imaging device <NUM> according to embodiments of the present disclosure will be described. <FIG> is a plan view schematically illustrating the solid-state imaging device <NUM> according to the present embodiment. As illustrated in <FIG>, the solid-state imaging device <NUM> according to the present embodiment includes a pixel array <NUM> in which a plurality of solid-state image sensors (pixels) <NUM> are arranged in a matrix on a semiconductor substrate <NUM> made of silicon, for example. As illustrated in <FIG>, the solid-state imaging device <NUM> further includes a vertical drive circuit <NUM>, a column signal processing circuit <NUM>, a horizontal drive circuit <NUM>, an output circuit <NUM>, and a control circuit <NUM>. The detail of each block of the solid-state imaging device <NUM> according to the present embodiment will be described below.

The pixel array <NUM> has a plurality of solid-state image sensors <NUM> two-dimensionally arranged in a matrix (in columns and rows) on the semiconductor substrate <NUM>. As used herein, "solid-state image sensor <NUM>" refers to a solid-state image sensor (unit pixel) considered as a unit that detects light of colors and outputs one result for each color every time it outputs a detection result. Each solid-state image sensor <NUM> includes a plurality of photoelectric conversion elements (photodiodes (PD)) (photoelectric converters) (for example, as illustrated in <FIG>, the solid-state image sensor <NUM> can include stacked three PDs <NUM>, <NUM>, and <NUM>) capable of generating charge in accordance with the quantity of incident light of each color and a plurality of pixel transistors (for example, metal-oxide-semiconductor (MOS) transistors) (not illustrated). More specifically, the pixel transistors can include, for example, a transfer transistor, a select transistor, a reset transistor, and an amplifier transistor.

The solid-state image sensor <NUM> described above may be configured as a common pixel structure. This common pixel structure is constituted with a plurality of the PDs, a plurality of the transfer transistors, one floating diffusion (floating diffusion region) (charge accumulator) shared among the PDs for accumulating charge generated in the PDs, and other pixel transistors each shared among the PDs. That is, in the common pixel structure, a plurality of photoelectric conversion pairs configured with a PD and a transfer transistor are provided, and each photoelectric conversion pair shares other pixel transistors (select transistor, reset transistor, amplifier transistor, and the like). The detail of the circuit (connection configuration) of these pixel transistors will be described later.

The vertical drive circuit <NUM> is formed with, for example, a shift register, selects pixel drive wiring <NUM>, supplies a pulse for driving the solid-state image sensors <NUM> to the selected pixel drive wiring <NUM>, and drives the solid-state image sensors <NUM> in units of rows. That is, the vertical drive circuit <NUM> selectively scans the solid-state image sensors <NUM> in the pixel array <NUM> in units of rows sequentially in the vertical direction (the top-down direction in <FIG>) and supplies a pixel signal based on the charge generated in accordance with the quantity of received light of the PD in each solid-state image sensor <NUM>, to the column signal processing circuit <NUM> through a vertical signal line <NUM>.

The column signal processing circuit <NUM> is arranged for each column of the solid-state image sensors <NUM> and performs signal processing such as noise removal for each pixel column for pixel signals output from the solid-state image sensors <NUM> of one column. For example, the column signal processing circuit <NUM> performs signal processing such as correlated double sampling (CDS) and analog-digital (AD) conversion for removing fixed pattern noise unique to pixels.

The horizontal drive circuit <NUM> is formed, for example, with a shift register, sequentially outputs a horizontal scan pulse to select each of the column signal processing circuits <NUM> in order, and allows each of the column signal processing circuits <NUM> to output a pixel signal to a horizontal signal line <NUM>.

The output circuit <NUM> can perform signal processing on a pixel signal sequentially supplied from each of the column signal processing circuits <NUM> through the horizontal signal line <NUM>, and output the processed signal. The output circuit <NUM> may function, for example, as a function unit that performs buffering or may perform processing such as black level adjustment, column variation correction, and a variety of digital signal processing. Buffering refers to temporarily storing a pixel signal in order to compensate for differences in processing speed and transfer speed in exchanging pixel signals. An input/output terminal <NUM> is a terminal for exchanging signals with an external device.

The control circuit <NUM> can receive an input clock and data indicating an operation mode and can output data such as internal information of the solid-state image sensors <NUM>. That is, the control circuit <NUM> generates a control signal and a clock signal serving as a reference of operation for the vertical drive circuit <NUM>, the column signal processing circuits <NUM>, the horizontal drive circuit <NUM>, and the like, based on a vertical sync signal, a horizontal sync signal, and a master clock. The control circuit <NUM> then outputs the generated clock signal and control signal to the vertical drive circuit <NUM>, the column signal processing circuits <NUM>, the horizontal drive circuit <NUM>, and the like.

As described above, the solid-state imaging device <NUM> described above is a CMOS image sensor called a column AD type in which the column signal processing circuit <NUM> performing CDS processing and AD conversion processing is arranged for each pixel column. The planar configuration example of the solid-state imaging device <NUM> according to the present embodiment is not limited to the example illustrated in <FIG> and, for example, may include other circuits.

The overall configuration of the solid-state imaging device <NUM> according to the present embodiment has been described above. An equivalent circuit of the PDs <NUM>, <NUM>, and <NUM> included in the solid-state image sensor <NUM> according to embodiments of the present disclosure will now be described with reference to <FIG> and <FIG>. <FIG> is an equivalent circuit diagram of the PD <NUM> included in the solid-state image sensor <NUM> according to the present embodiment, and <FIG> is an equivalent circuit diagram of the PD <NUM> included in the solid-state image sensor <NUM> according to the present embodiment.

As schematically illustrated in the upper left in <FIG>, the stack structure of the PD <NUM>, which will be detailed later, is a stack structure including an upper electrode (common electrode) <NUM>, a lower electrode (readout electrode) <NUM>, and a photoelectric conversion film <NUM> sandwiched between the upper electrode <NUM> and the lower electrode <NUM>, which are stacked above the semiconductor substrate <NUM> that is a silicon substrate.

As illustrated in <FIG>, the upper electrode <NUM> is electrically connected to a select line Vou that selects a column to output a pixel signal. The lower electrode <NUM> is electrically connected through wiring or the like to one of the drain and source of a reset transistor TR1rst for resetting the accumulated charge. The gate of the reset transistor TR1rst is electrically connected to a reset signal line RST1 and further electrically connected to the vertical drive circuit <NUM> described above. The other of the drain and source of the reset transistor TR1rst (the side not connected to the lower electrode <NUM>) is electrically connected to a power supply circuit VDD.

The lower electrode <NUM> is electrically connected through wiring to the gate of an amplifier transistor TR1amp that converts charge to a voltage and outputs the voltage as a pixel signal. A node FD<NUM> connecting the lower electrode <NUM>, the gate of the amplifier transistor TR1amp, and one of the drain and source of the reset transistor TR1rst forms a part of the reset transistor TR1rst. Charge from the lower electrode <NUM> changes the potential on the node FD<NUM> and is converted to a voltage by the amplifier transistor TR1amp. One of the source and drain of the amplifier transistor TR1amp is electrically connected through wiring to one of the source and drain of the select transistor TR1sel outputting the pixel signal obtained through conversion to a signal line VSL1 in accordance with a select signal. The other (the side not connected to the select transistor TR1sel) of the source and drain of the amplifier transistor TR1amp is electrically connected to the power supply circuit VDD.

The other (the side not connected to the amplifier transistor TR1amp) of the source and drain of the select transistor TR1sel is electrically connected to the signal line VSL1 that transmits the converted voltage as a pixel signal, and is further electrically connected to the column signal processing circuit <NUM> described above. The gate of the select transistor TR1sel is electrically connected to the select line SEL1 that selects a row to output a pixel signal, and is further electrically connected to the vertical drive circuit <NUM> described above.

An equivalent circuit of the PD <NUM> provided in the semiconductor substrate <NUM> will now be described with reference to <FIG>. As illustrated in <FIG>, the PD <NUM> provided in the semiconductor substrate <NUM> is electrically connected through wiring to pixel transistors (an amplifier transistor TR2amp, a transfer transistor TR2trs, a reset transistor TR2rst, a select transistor TR2sel) provided in the semiconductor substrate <NUM>. Specifically, one side of the PD <NUM> is electrically connected through wiring to one of the source and drain of the transfer transistor TR2trs that transfers charge. The other (the side not connected to the PD <NUM>) of the source and drain of the transfer transistor TR2trs is electrically connected through wiring to one of the source and drain of the reset transistor TR2rst. The gate of the transfer transistor TR2trs is electrically connected to a transfer gate line TG2 and is further connected to the vertical drive circuit <NUM> described above. The other (the side not connected to the transfer transistor TR2trs) of the source and drain of the reset transistor TR2rst is electrically connected to the power supply circuit VDD. The gate of the reset transistor TR2rst is electrically connected to a reset line RST2 and is further connected to the vertical drive circuit <NUM> described above.

The other (the side not connected to the PD <NUM>) of the source and drain of the transfer transistor TR2trs is also electrically connected through wiring to the gate of the amplifier transistor TR2amp that amplifies (converts) charge and outputs as a pixel signal. One of the source and drain of the amplifier transistor TR2amp is electrically connected through wiring to one of the source and drain of the select transistor TR2sel that outputs the pixel signal to the signal line VSL2 in accordance with a select signal. The other (the side not connected to the select transistor TR2sel) of the source and drain of the amplifier transistor TR2amp is electrically connected to the power supply circuit VDD. The other (the side not connected to the amplifier transistor TR2amp) of the source and drain of the select transistor TR2sel is electrically connected to the signal line VSL2 and is further electrically connected to the column signal processing circuit <NUM> described above. The gate of the select transistor TR2sel is electrically connected to the select line SEL2 and is further electrically connected to the vertical drive circuit <NUM> described above.

Similar to the PD <NUM>, the PD <NUM> provided in the semiconductor substrate <NUM> can also be represented similarly to the equivalent circuit in <FIG>, and a description of an equivalent circuit of the PD <NUM> is omitted here.

The equivalent circuit of the PDs <NUM>, <NUM>, and <NUM> included in the solid-state image sensor <NUM> according to the present embodiment has been described above. Referring now to <FIG>, the stack structure of the solid-state image sensor <NUM> according to embodiments of the present disclosure will be described. <FIG> is a cross-sectional view of the solid-state image sensor <NUM> according to the present embodiment, specifically a cross-sectional view of the solid-state image sensor <NUM> cut along the through direction of the through electrode <NUM>. In <FIG>, the solid-state image sensor <NUM> is illustrated such that an incident surface on which light enters the solid-state image sensor <NUM> faces up. In the following description, the stack structure in the solid-state image sensor <NUM> will be described in order from the semiconductor substrate <NUM> positioned on the lower side of the solid-state image sensor <NUM> toward the PD <NUM> positioned above the semiconductor substrate <NUM>.

First, as illustrated in <FIG>, in the solid-state image sensor <NUM> according to the present embodiment, for example, in a semiconductor region <NUM> having a first conductivity type (for example, P-type) of the semiconductor substrate <NUM> made of silicon, two semiconductor regions <NUM> and <NUM> having a second conductivity type (for example, N-type) are formed in an overlapped manner in the thickness direction (depth direction) of the semiconductor substrate <NUM>. The thus formed semiconductor regions <NUM> and <NUM> form a PN junction to serve as stacked two PDs <NUM> and <NUM>. For example, the PD <NUM> having the semiconductor region <NUM> as a charge accumulation region is a photoelectric conversion element that absorbs blue light (for example, wavelengths of <NUM> to <NUM>) to generate charge (photoelectric conversion), and the PD <NUM> having the semiconductor region <NUM> as a charge accumulation region is a photoelectric conversion element that absorbs red light (for example, wavelengths of <NUM> to <NUM>) to generate charge.

A wiring layer <NUM> is provided on the surface (the lower side in <FIG>) on the side opposite to the incident surface of the semiconductor substrate <NUM> on which the PD <NUM> and the like are stacked. The wiring layer <NUM> includes gate electrodes <NUM> of a plurality of pixel transistors for reading the charge accumulated in the PDs <NUM>, <NUM>, and <NUM>, a plurality of wiring <NUM>, and an interlayer insulating film <NUM>. For example, the gate electrodes <NUM> and the wiring <NUM> can be formed of a material such as tungsten (W), aluminum (Al), and copper (Cu). The interlayer insulating film <NUM> can be formed of, for example, silicon oxide (SiO<NUM>) or silicon nitride (SiN).

The semiconductor substrate <NUM> has the through electrode <NUM> that passes through the semiconductor substrate <NUM> to extract the charge generated by photoelectric conversion in the PD <NUM> described later to a floating diffusion <NUM> described later. Specifically, a conductor <NUM> serving as the center axis of the through electrode <NUM> can be formed of, for example, a doped silicon 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). On the outer periphery of the conductor <NUM>, an insulating film <NUM> made of SiO<NUM> or SiN is formed for suppressing short-circuiting to the semiconductor region <NUM>. In the present embodiment, a barrier metal film (not illustrated) may be provided between the conductor <NUM> and the insulating film <NUM> surrounding the outer periphery of the conductor <NUM>. The barrier metal film can be formed from a material such as titanium nitride (TiN), tungsten nitride (WN), Ti, tantalum nitride (TaN), and Ta.

The through electrode <NUM> may be connected to a floating diffusion <NUM> provided in a semiconductor region having the second conductivity type (for example, N-type) provided in the semiconductor substrate <NUM>, through the wiring <NUM> provided in the wiring layer <NUM>. That is, the through electrode <NUM> can electrically connect the PD <NUM> (specifically, lower electrode <NUM>) to the floating diffusion <NUM>. The floating diffusion <NUM> can temporarily accumulate the charge generated by photoelectric conversion in the PD <NUM>, through the through electrode <NUM>.

As previously described, the wiring layer <NUM> has a plurality of gate electrodes <NUM> as the gate electrodes of a plurality of pixel transistors that read out the charge generated in the above-noted PD <NUM>. Specifically, an electrode <NUM> is provided to face the semiconductor region <NUM> having the first conductivity type (for example, P-type) in the semiconductor substrate <NUM> with an insulating film <NUM> interposed therebetween. In the semiconductor substrate <NUM>, semiconductor regions <NUM> having the second conductivity type (for example, N-type) are further provided so as to sandwich the semiconductor region <NUM> having the first conductivity type. The semiconductor regions <NUM> function as the source and drain regions of the pixel transistor. The above-noted through electrode <NUM> can electrically connect the PD <NUM> (specifically, lower electrode <NUM>) to these pixel transistors. The detailed configuration of the through electrode <NUM> will be described later.

A fixed charge film <NUM> having negative fixed charge may be formed on the incident surface of the semiconductor substrate <NUM>. The fixed charge film <NUM> may be formed from, for example, hafnium oxide (HfO<NUM>), aluminum oxide (Al<NUM>O<NUM>), zirconium oxide (ZrO), tantalum oxide (Ta<NUM>O<NUM>), titanium oxide (TiO<NUM>), lanthanum oxide (La<NUM>O<NUM>), praseodymium oxide (Pr<NUM>O<NUM>), cerium oxide (CeO<NUM>), neodymium oxide (Nd<NUM>O<NUM>), promethium oxide (Pm<NUM>O<NUM>), samarium oxide (Sm<NUM>O<NUM>), europium oxide (Eu<NUM>O<NUM>), gadolinium oxide (Gd<NUM>O<NUM>), terbium oxide (Tb<NUM>O<NUM>), dysprosium oxide (Dy<NUM>O<NUM>), holmium oxide (Ho<NUM>O<NUM>), thulium oxide (Tm<NUM>O<NUM>), ytterbium oxide (Yb<NUM>O<NUM>), lutetium oxide (Lu<NUM>O<NUM>), yttrium oxide (Y<NUM>O<NUM>), aluminum nitride (AlN), hafnium oxynitride (HfON), aluminum oxynitride (AlON), and the like. The fixed charge film <NUM> may be a stack film made of different materials described above in combination.

An insulating film <NUM> is provided on the fixed charge film <NUM>. The insulating film <NUM> can be formed of, for example, a dielectric film having insulating properties, such as SiO<NUM>, tetraethyl orthosilicate (TEOS), silicon nitride (Si<NUM>N<NUM>), and silicon oxynitride (SiON).

On the insulating film <NUM>, the stack structure of the photoelectric conversion film <NUM> sandwiched between the upper electrode <NUM> and the lower electrode <NUM> is provided with an insulating film <NUM> interposed therebetween. The upper electrode <NUM>, the photoelectric conversion film <NUM>, and the lower electrode <NUM> constitute the PD <NUM> that converts light to charge. The PD <NUM> is, for example, a photoelectric conversion element that absorbs green light (for example, wavelengths of <NUM> to <NUM>) to generate charge (photoelectric conversion). The upper electrode <NUM> and the lower electrode <NUM> can be formed of, for example, a transparent conductive film such as indium tin oxide (ITO) and indium zinc oxide (IZO). Specifically, the upper electrode <NUM> is shared (in common) between adjacent pixels (solid-state image sensors <NUM>), whereas the lower electrode <NUM> is formed individually for each of the pixels. The lower electrode <NUM> is electrically connected to the above-noted through electrode <NUM> by metal wiring <NUM> passing through the insulating film <NUM>. The metal wiring <NUM> can be formed of, for example, a metal material such as W, Al, and Cu. The insulating film <NUM> can be formed of, for example, an insulating material that allows light to pass through, such as Al<NUM>O<NUM>, SiO<NUM>, Si<NUM>N<NUM>, and SiON.

As illustrated in <FIG>, a high-refractive index layer <NUM> made of an inorganic film such as Si<NUM>N<NUM>, SiON, and silicon carbide (SiC) and a planarization film <NUM> are formed on the upper electrode <NUM>. An on-chip lens <NUM> is provided on the planarization film <NUM>. The on-chip lens <NUM> can be formed of, for example, Si<NUM>N<NUM> or a resin-based material such as styrene resin, acrylic resin, styrene-acrylic copolymer resin, or siloxane resin.

As described above, the solid-state image sensor <NUM> according to the present embodiment has a stack structure in which the PDs <NUM>, <NUM>, and <NUM> respectively corresponding to three colors are stacked. That is, the solid-state image sensor <NUM> described above is a vertical spectral type solid-state image sensor that converts green light to electricity at above the semiconductor substrate <NUM>, that is, in the photoelectric conversion film <NUM> (PD <NUM>) formed on the incident surface side of the semiconductor substrate <NUM>, and converts blue and red light to electricity in the PDs <NUM> and <NUM> in the semiconductor substrate <NUM>. It can be said that the solid-state image sensor <NUM> 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.

The above-noted photoelectric conversion film <NUM> can be formed from an organic material (organic photoelectric conversion film) or an inorganic material (inorganic photoelectric conversion film). For example, when the photoelectric conversion film <NUM> is formed from an organic material, any one of the following four modes can be selected: (a) a P-type organic semiconductor material; (b) an N-type organic semiconductor material; (c) a stack structure of at least two of a P-type organic semiconductor material layer, an N-type organic semiconductor material layer, and a mixed layer of a P-type organic semiconductor material and an N-type organic semiconductor material (bulk hetero structure); and (d) a mixed layer of a P-type organic semiconductor material and an N-type organic semiconductor material.

Specifically, examples of the P-type organic semiconductor material 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, perylene derivatives, picene derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrazine derivatives, metal complexes having heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives.

Examples of the N-type organic semiconductor material include fullerenes and fullerene derivatives <for example, fullerenes such as C60, C70, and C74 (higher fullerenes), endohedral fullerenes, and the like, or fullerene derivatives (for example, fullerene fluorides, phenyl-C<NUM>-butyric acid methyl ester (PCBM) fullerene compounds, fullerene polymers, and the like)>, organic semiconductors having a highest occupied molecular orbital (HOMO) and a lowest unoccupied molecular orbital (LUMO) deeper than those of P-type organic semiconductors, and transparent inorganic metal oxides. More specifically, examples of the N-type organic semiconductor material include heterocyclic compounds containing nitrogen atom, oxygen atom, and sulfur atom, for example, organic molecules, organic metal complexes, and subphthalocyanine derivatives, having, in a part of molecular skeleton, a pyridine derivative, a pyrazine derivative, a pyrimidine derivative, a triazine derivative, a quinoline derivative, a quinoxaline derivative, an isoquinoline derivative, an acridine derivative, a phenazine derivative, a phenanthroline derivative, a tetrazole derivative, a pyrazole derivative, an imidazole derivative, a thiazole derivative, an oxazole derivative, an imidazole derivative, a benzimidazole derivative, a benzotriazole derivative, a benzoxazole derivative, a benzoxazole derivative, a carbazole derivative, a benzofuran derivative, a dibenzofuran derivative, a subporphyrazine derivative, a polyphenylene vinylene derivative, a polybenzothiadiazole derivative, a polyfluorene derivative, or the like. Examples of the group included in the fullerene derivatives include branched or cyclic alkyl group or phenyl group; group having a linear or fused aromatic compound; group having a halide; partial fluoroalkyl group; perfluoroalkyl group; silylalkyl group; silylalkoxy group; arylsilyl group; arylsulfanil group; alkylsulfanil group; arylsulfonyl group; alkylsulfonyl group; arylsulfide group; alkylsulfide group; amino group; alkylamino group; arylamino group; hydroxy group; alkoxy group; acylamino group; acyloxy group; carbonyl group; carboxy group; carboxamido group; carboalkoxy group; acyl group; sulfonyl group; cyano group; nitro group; group having a chalcogenide; phosphino group; phosphono group; and derivatives thereof. The film thickness of the photoelectric conversion film <NUM> formed from an organic material may be, for example, but not limited to, <NUM>×<NUM>-<NUM> m to <NUM>×<NUM>-<NUM> m, preferably <NUM>×<NUM>-<NUM> m to <NUM>×<NUM>-<NUM> m, more preferably from <NUM>×<NUM>-<NUM> m to <NUM>×<NUM>-<NUM> m. In the foregoing description, the organic semiconductor materials are classified into P-type and N-type. As used herein, the P-type means that holes are easily transported, and the N-type means that electrons are easily transported. That is, the organic semiconductor materials are not necessarily interpreted as having holes or electrons as thermally excited major carriers, like inorganic semiconductor materials.

More specifically, in order to function as the photoelectric conversion film <NUM> of the PD <NUM> that receives green light and converts light into electricity, the photoelectric conversion film <NUM> can contain, for example, a rhodamine-based pigment, a merocyanine-based pigment, a quinacridone derivative, a subphthalocyanine-based pigment (subphthalocyanine derivative), and the like.

When the photoelectric conversion film <NUM> is formed from an inorganic material, examples of the inorganic semiconductor material include crystalline silicon, amorphous silicon, microcrystalline silicon, crystalline selenium, amorphous selenium, and chalcopyrite-based compounds such as CIGS (CuInGaSe), CIS (CuInSe<NUM>), CuInS<NUM>, CuAlS<NUM>, CuAlSe<NUM>, CuGaS<NUM>, CuGaSe<NUM>, AgAlS<NUM>, AgAlSe<NUM>, AgInS<NUM>, AgInSe<NUM>, or III-V group compounds such as GaAs, InP, AlGaAs, InGaP, AlGaInP, and InGaAsP, and compound semiconductors such as CdSe, CdS, In<NUM>Se<NUM>, In<NUM>S<NUM>, Bi<NUM>Se<NUM>, Bi<NUM>S<NUM>, ZnSe, ZnS, PbSe, and PbS. In addition, quantum dots made of the above-noted materials may be used as the photoelectric conversion film <NUM>.

In the present embodiment, the solid-state image sensor <NUM> described above is not limited to the structure of a stack of the PD <NUM> having the photoelectric conversion film <NUM> provided above the semiconductor substrate <NUM> and the PDs <NUM> and <NUM> provided in the semiconductor substrate <NUM>. For example, in the present embodiment, the solid-state image sensor <NUM> may be a stack structure including the PD <NUM> having the photoelectric conversion film <NUM> provided above the semiconductor substrate <NUM> and the PD <NUM> provided in the semiconductor substrate <NUM>, that is, a stack structure of two PDs <NUM> and <NUM>. In the present embodiment, the solid-state image sensor <NUM> may be a structure having two or three PDs <NUM> stacked above the semiconductor substrate <NUM>. In such a case, the PDs <NUM> may have respective photoelectric conversion films <NUM>, and the photoelectric conversion films <NUM> may be formed of an organic semiconductor material or may be formed of an inorganic semiconductor material. In this case, in order to function as the photoelectric conversion film <NUM> of the PD <NUM> that receives blue light and converts the light into electricity, the photoelectric conversion film <NUM> may contain, for example, a coumaric acid pigment, tris-(<NUM>-hydroxyquinoline)aluminum (Alq<NUM>), a merocyanine-based pigment, or the like. In order to function as the photoelectric conversion film <NUM> of the PD <NUM> that receives red light and converts the light into electricity, the photoelectric conversion film <NUM> may contain a phthalocyanine-based pigment, a subphthalocyanine-based pigment (subphthalocyanine derivative), or the like.

Prior to a detailed description of embodiments according to the present disclosure, circumstances leading to embodiments of the present disclosure made by the inventors of the present invention will be described with reference to <FIG> is a diagram for explaining circumstances leading to creation of embodiments of the present disclosure. Specifically, the left side of <FIG> schematically illustrates a cross section of a through electrode <NUM> according to a comparative example, and the right side of <FIG> schematically illustrates a cross section of the through electrode <NUM> according to embodiments of the present disclosure. As used herein, the comparison example means the through electrode <NUM> that had been studied before the inventors of the present invention made embodiments of the present disclosure.

The inventors have so far contemplated providing the through electrode <NUM> (<NUM>) for each solid-state image sensor (pixel) <NUM>. In this case, in order to achieve satisfactory sensitivity of the solid-state image sensor <NUM>, it is preferable to ensure a large light incident surface on which light enters, in other words, it is preferable to ensure a large area occupied by the PDs <NUM> and <NUM>. When the through electrode <NUM> is provided for each solid-state image sensor <NUM>, therefore, the through electrode <NUM> is preferably more minute (for example, with a smaller diameter) in order to ensure a large light incident surface on which light enters. According to studies by the inventors of the present invention, it is preferable that the diameter of the conductor <NUM> (<NUM>) of the through electrode <NUM> is, for example, about <NUM>. The inventors then fabricated the through electrode <NUM> of the comparative example that had such a configuration as the through electrode disclosed in Patent Literature <NUM> above with a small diameter as described above, and found that it was difficult to keep the resistance value of the through electrode <NUM> low.

Specifically, the inventors of the present invention had fabricated minute through electrodes <NUM> (comparative example) as follows before creating embodiments of the present disclosure. First, as illustrated in the left side of <FIG>, a through hole <NUM> is formed to pass through the semiconductor substrate <NUM> substantially vertically to the semiconductor substrate <NUM>. An insulating film <NUM> is further formed to cover the inner wall of the through hole <NUM>. Subsequently, a conductor <NUM> is deposited to fill in the through hole <NUM> by chemical vapor deposition (CVD).

According to studies by the inventors of the present invention, when the conductor <NUM> is deposited to fill in the through hole <NUM>, as illustrated in the left side of <FIG>, a void <NUM> is produced in the through hole <NUM>. Presumably, the void <NUM> is produced as follows. It is known that when a film is deposited by CVD, the film is deposited so as to conform to the shape of the substrate. It is also known that when a film is deposited by CVD to fill in the through hole <NUM>, the film adheres to the inner wall of the through hole <NUM> more easily on its upper portion, and the film tends to be deposited more easily on the upper portion of the inner wall of the through hole <NUM> than on the lower portion of the inner wall. It is therefore assumed that when the conductor <NUM> is deposited to fill in the through hole <NUM>, the conductor <NUM> in the form of an overhang extending from the upper portion of the inner wall of the through hole <NUM> tends to be formed. As the deposition of the conductor <NUM> proceeds, an additional overhang-shaped film of the conductor <NUM> is formed on the above-noted overhang-shaped film, and eventually, the deposited conductor <NUM> is shaped like a cap, which presumably causes the void <NUM> in the through hole <NUM>. That is, in the comparative example, as illustrated in the left side of <FIG>, although the upper portion of the through hole <NUM> is closed by the conductor <NUM>, the void <NUM> remains in the inside of the through hole <NUM>. In other words, the through hole <NUM> sometimes fails to be filled with the conductor <NUM>. In this case, since the through hole <NUM> fails to be filled with the conductor <NUM>, the resistance value of the through electrode <NUM> increases. According to studies by the inventors of the present invention, the phenomenon as described above occurs more conspicuously as the through electrode <NUM> is downsized and the aspect ratio of the through hole <NUM> is increased.

In view of such a situation, the inventors of the present invention have created embodiments of the present disclosure related to the through electrode <NUM> in which the through hole <NUM> can be filled with the conductor <NUM>, by avoiding occurrence of the void <NUM> in the through hole <NUM> in order to keep the resistance value of the through electrode <NUM> low.

In the comparative example, as illustrated in the left side of <FIG>, the cross-sectional area of the conductor <NUM> of the through electrode <NUM> in a cut section orthogonal to the through direction of the through electrode <NUM> is constant, and the conductor <NUM> is shaped like a cylinder. By contrast, in embodiments of the present disclosure, as illustrated in the right side of <FIG>, at the upper portion (the end portion on the PD <NUM> side) of the through electrode <NUM>, the cross-sectional area of the conductor <NUM> in a cut section orthogonal to the through direction of the through electrode <NUM> gradually increases upward along the through direction. That is, in the present embodiment, the upper portion of the conductor <NUM> has a tapered shape. More specifically, in the present embodiment, during fabrication of the through electrode <NUM> having the tapered conductor <NUM> as described above, the diameter of the upper portion of the through hole <NUM> with the inner wall covered with the insulating film <NUM> is increased, and the conductor <NUM> is deposited to fill in the through hole <NUM> having the diameter increased. According to the present embodiment, the diameter of the upper portion of the through hole <NUM> is increased to allow the conductor <NUM> to easily reach the bottom portion of the through hole <NUM>, thereby improving the filling characteristic of the conductor <NUM> and avoiding occurrence of the void <NUM> in the through hole <NUM>. As a result, according to the present embodiment, the resistance value of the through electrode <NUM> can be kept low. The detail of embodiments according to the present disclosure will be described in order below.

Referring first to <FIG>, a detailed configuration of the through electrode <NUM> according to a first embodiment of the present disclosure is described. <FIG> is a partial enlarged view of a cross section (<FIG>) of the solid-state image sensor <NUM> according to the present embodiment, specifically, an enlarged view of the through electrode <NUM> and the periphery of the through electrode <NUM>. <FIG> is a cross-sectional view of the through electrode <NUM> cut along line A-A' and line B-B' in <FIG>. Specifically, the upper part of <FIG> illustrates a cross-sectional view of the through electrode <NUM> cut along line A-A' in <FIG>, and the lower part of <FIG> illustrates a cross-sectional view of the through electrode <NUM> cut along line B-B' in <FIG>. <FIG> is a diagram illustrating the upper portion of the through electrode <NUM> according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode <NUM> cut along the through direction of the through electrode <NUM>. In <FIG>, a fixed charge film <NUM> is not illustrated for ease of understanding.

As illustrated in <FIG>, the through electrode <NUM> according to the present embodiment mainly includes a through hole <NUM> passing through the semiconductor substrate <NUM> substantially vertically to the semiconductor substrate <NUM> (in other words, passing through along the film thickness direction of the semiconductor substrate <NUM>), the fixed charge film <NUM> covering the inner wall of the through hole <NUM>, the insulating film <NUM> covering the inner wall with the fixed charge film <NUM> interposed therebetween, and the conductor <NUM> filling the through hole <NUM>. As previously described, a barrier metal film (not illustrated) may be provided between the conductor <NUM> and the insulating film <NUM> surrounding the outer periphery of the conductor <NUM>. The detail of the parts of the through electrode <NUM> will be described in order below.

In the present embodiment, the through hole <NUM> is, for example, a hole in the shape of a cylinder or a truncated cone having a taper, preferably a cylindrical or substantially cylindrical hole (in other words, a hole having an opening diameter substantially equal in the through direction). In the present embodiment, the through hole <NUM> is a substantially cylindrical hole so that the film thickness of the insulating film <NUM> covering the inner wall of the through hole <NUM> can be even more uniform. According to the present embodiment, therefore, while the insulation between the through electrode <NUM> (specifically, the conductor <NUM>) and the semiconductor substrate <NUM> (specifically, the semiconductor region <NUM>) is ensured, the parasitic capacitance of the through electrode <NUM> caused by the insulating film <NUM> can be reduced. As a result, since the parasitic capacitance can be reduced, the present embodiment can avoid unintentional transmittance of noise to the through electrode <NUM> through the parasitic capacitance and consequently can avoid deterioration in characteristics of the solid-state image sensor <NUM>.

In the present embodiment, as previously described, the fixed charge film <NUM> is provided to cover the inner wall and the bottom surface (the lower surface) of the through hole <NUM>. For example, the fixed charge film <NUM> can be formed of HfO<NUM>, Al<NUM>O<NUM>, ZrO, Ta<NUM>O<NUM>, TiO<NUM>, or the like, similarly to the fixed charge film <NUM> described above. The fixed charge film <NUM> may be a stack film of the aforementioned different materials in combination.

In the present embodiment, as previously described, the insulating film <NUM> is provided to cover the inner wall of the through hole <NUM> with the fixed charge film <NUM> interposed therebetween. The insulating film <NUM> is provided to cover the outer periphery of the conductor <NUM> described later. The insulating film <NUM> is an insulating film for suppressing short-circuiting to the semiconductor substrate <NUM> (specifically, the semiconductor region <NUM>) and formed of SiO<NUM>, SiN, or the like.

In the present embodiment, the conductor <NUM> is provided to fill in the through hole <NUM> having the inner wall covered with the fixed charge film <NUM> and the insulating film <NUM>. In other words, as illustrated in <FIG>, the conductor <NUM> is positioned at the center of the through electrode <NUM>. Specifically, the conductor <NUM> is a substantially cylindrical electrode passing through the center portion of the through hole <NUM> and has a tapered shape at its upper portion (the end portion on the PD <NUM> side). The conductor <NUM> further passes through the bottom surface (the lower surface) of the through hole <NUM> to extend to the wiring <NUM> of the wiring layer <NUM>. As previously described, the conductor <NUM> can be formed of, for example, a doped silicon material such as PDAS or a metal material such as Al, W, Ti, Co, Hf, and Ta.

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

Further referring to <FIG>, the conductor <NUM> will be described in more detail. The lower part of <FIG> illustrates a cut section when the through electrode <NUM> is cut through a plane (line B-B' in <FIG>) orthogonal to the through direction of the through electrode <NUM>, below the fixed charge film <NUM>. The upper part of <FIG> illustrates a cut section when the through electrode <NUM> is cut through a plane (line A-A' in <FIG>) orthogonal to the through direction of the through electrode <NUM>, at the insulating film <NUM>. As illustrated in the upper drawing and the lower drawing of <FIG>, in the present embodiment, the conductor <NUM> has the diameter increasing upward. More specifically, in the present embodiment, the diameter of the conductor <NUM> in a cut section at the upper portion (the end portion on the PD <NUM> side) of the through electrode <NUM>, in other words, the diameter D<NUM> (see the upper drawing in <FIG>) of the conductor <NUM> when the through electrode <NUM> is cut along line A-A' in <FIG> is <NUM> times or more the diameter of the conductor <NUM> in a cut section at the lower portion (the end portion on the floating diffusion <NUM> side) of the through electrode <NUM>, in other words, the diameter D<NUM> (see the lower drawing in <FIG>) of the conductor <NUM> when the through electrode <NUM> is cut along line B-B' of <FIG>.

In the present embodiment, when the through electrode <NUM> is cut along line B-B' in <FIG>, the diameter D<NUM> (see the lower drawing in <FIG>) of the conductor <NUM> is preferably <NUM> to <NUM>. In the present embodiment, when the through electrode <NUM> is cut along line A-A' in <FIG>, the diameter D<NUM> (see the upper drawing in <FIG>) of the conductor <NUM> is preferably <NUM> to <NUM>.

It is preferable that the upper surface (the surface on the PD <NUM> side) of the conductor <NUM> is large in order to ensure the contact with the metal wiring <NUM>. However, with a large upper surface of the conductor <NUM>, incidence of light on the PDs <NUM> and <NUM> positioned below relative to the upper surface of the conductor <NUM> is interrupted by the upper surface of the conductor <NUM>. In the present embodiment, therefore, it is preferable that the upper surface of the conductor <NUM> is small to such an extent that the contact with the metal wiring <NUM> can be ensured. In the present embodiment, it is preferable that the upper surface of the conductor <NUM> is larger than the cut section of the conductor <NUM> (see the upper drawing in <FIG>) when the through electrode <NUM> is cut along line A-A' in <FIG>, and is smaller than the opening of the through hole <NUM> (specifically, the opening of the through hole <NUM> with the inner wall not covered with the fixed charge film <NUM> and the insulating film <NUM>).

In the present embodiment, as illustrated in <FIG> illustrating a partially enlarged view of a cross section of the through electrode <NUM> cut along the through direction of the through electrode <NUM>, at the upper portion (the end portion on the PD <NUM> side) of the through electrode <NUM>, the gradient of the outer peripheral surface of the conductor <NUM> of the through electrode <NUM> preferably has an angle of <NUM>° or more and <NUM>° or less with respect to the center axis <NUM> of the conductor <NUM> extending in the through direction. In the present embodiment, it is preferable that the gradient is set to such a value that can ensure that the insulating film <NUM> has a film thickness capable of suppressing short-circuiting to the semiconductor substrate <NUM> (specifically, the semiconductor region <NUM>) and also can ensure a large light incident surface on which light enters for the PDs <NUM> and <NUM>.

In the present embodiment, as long as the conductor <NUM> has a tapered shape at the upper portion (the end portion on the PD <NUM> side) of the through electrode <NUM>, the entire through hole <NUM> passing through the semiconductor substrate <NUM> (through the film thickness of the semiconductor substrate <NUM>) may be tapered, and the taper shape is not limited.

In the present embodiment, when the through electrode <NUM> having the conductor <NUM> having the shape as described above is formed, which will be detailed later, the diameter at the upper portion of the through hole <NUM> with the inner wall covered with the insulating film <NUM> is increased, and the conductor <NUM> is deposited to fill in the through hole <NUM> having the diameter increased. According to the present embodiment, the diameter of the upper portion of the through hole <NUM> is increased to allow the conductor <NUM> to easily reach the bottom portion of the through hole <NUM>, thereby improving the filling characteristic of the conductor <NUM> and avoiding occurrence of the void <NUM> in the through hole <NUM>. As a result, according to the present embodiment, the resistance value of the through electrode <NUM> can be kept low.

The detailed configuration of the through electrode <NUM> according to the present embodiment has been described above. A method of manufacturing the solid-state image sensor <NUM> including the through electrode <NUM> according to the present embodiment will now be described with reference to <FIG> are diagrams for explaining the method of manufacturing the solid-state image sensor <NUM> according to the present embodiment and illustrating a cross section of the solid-state image sensor <NUM> in the steps of the manufacturing method, which corresponds to the cross-sectional view in <FIG>.

First, as illustrated in <FIG>, the semiconductor substrate <NUM> is processed from the light incident surface side, for example, by dry etching to form a through hole 606a passing through the semiconductor substrate <NUM>.

Subsequently, as illustrated in <FIG>, fixed charge films <NUM> and <NUM> and insulating films <NUM> and <NUM> are deposited to cover the inner wall and the bottom surface of the through hole 606a and the incident surface of the semiconductor substrate <NUM>.

Then, as illustrated in <FIG>, the fixed charge film <NUM> and the insulating films <NUM> and <NUM> are partially removed, for example, by dry etching to form a through hole 606b passing through the semiconductor substrate <NUM> and extending to the wiring <NUM>. In doing so, the insulating films <NUM> and <NUM> formed on the periphery of the opening of the upper side of the through hole 606b are partially removed to increase the diameter of the opening on the upper side of the through hole 606b.

Subsequently, as illustrated in <FIG>, the conductor <NUM> (metal film) is deposited to fill in the through hole 606b. In doing so, as will be described later, the conductor <NUM> may be depressed at the center of the through hole 606b when the through hole 606b is viewed from above.

Then, as illustrated in <FIG>, the conductor <NUM> is partially removed, for example, by dry etching to form the through electrode <NUM>.

The metal wiring <NUM> and the insulating film <NUM> are further formed. Subsequently, the lower electrode <NUM>, the photoelectric conversion film <NUM>, the upper electrode <NUM>, the high-refractive index layer <NUM>, and the like are formed. Finally, the planarization film <NUM> and the on-chip lens <NUM> are formed. The solid-state image sensor <NUM> illustrated in <FIG> can be obtained as described above.

The solid-state image sensor <NUM> according to the present embodiment can be manufactured using methods, devices, and conditions used for manufacturing common semiconductor devices. That is, the solid-state image sensor <NUM> according to the present embodiment can be manufactured using the existing method of manufacturing a semiconductor device as follows.

Examples of the manufacturing method 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, facing target sputtering, high frequency sputtering, etc.), ion plating, laser ablation, molecular beam epitaxy (MBE), and laser transfer. Examples of CVD may include plasma CVD, thermal CVD, organic metal (MO) CVD, and photo-CVD. Examples of other methods may include electroplating, electroless plating, spin coating; dipping; casting; micro-contact 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, cast coater, spray coater, slit orifice coater, and calender coater. Examples of patterning may include chemical etching such as shadow mask, laser transfer, and photolithography, and physical etching using ultraviolet rays, laser, and the like. In addition, examples of planarization techniques may include chemical mechanical polishing (CMP), laser planarization, and reflowing.

As described above, in the present embodiment, during fabrication of the through electrode <NUM> having the conductor <NUM>, the diameter of the upper portion of the through hole 606a with the inner wall covered with the insulating film <NUM> is increased, and the conductor <NUM> is deposited to fill in the through hole 606b having the diameter increased. According to the present embodiment, the diameter of the upper portion of the through hole 606a is increased to allow the conductor <NUM> to easily reach the bottom portion of the through hole 606b, thereby improving the filling characteristic of the conductor <NUM> and avoiding occurrence of the void <NUM> in the through hole 606b. As a result, according to the present embodiment, the resistance value of the through electrode <NUM> can be kept low.

In the solid-state image sensor <NUM> according to the present embodiment, the upper portion (the end portion on the PD <NUM> side) of the conductor <NUM> may be electrically connected to wiring formed of a transparent conductor. In other words, in the present embodiment, the metal wiring <NUM> in <FIG> may be formed of a transparent conductor.

A method of manufacturing the solid-state image sensor <NUM> according to the present modification will be described below with reference to <FIG> described above. As illustrated in <FIG>, the conductor <NUM> is partially removed, for example, by dry etching, and after the through electrode <NUM> is formed, a transparent conductor is deposited on the through electrode <NUM>. The transparent conductor is partially removed, for example, by dry etching to form a wiring structure. The wiring <NUM> of the solid-state image sensor <NUM> according to the modification thus can be formed. The transparent conductor can be formed of a material such as ITO and IZO.

In the present modification, the metal wiring <NUM> is formed of a transparent conductor to prevent light incident on the wiring <NUM> from being reflected and unintentionally being incident on the PDs <NUM>, <NUM>, and <NUM>, thereby reducing occurrence of color mixing or flare in the solid-state image sensor <NUM>.

In embodiments of the present disclosure, the through electrode <NUM> according to the foregoing first embodiment can be further modified. Referring to <FIG> and <FIG>, a through electrode 600a according to the invention will be described. <FIG> is a cross-sectional view of a solid-state image sensor 100a according to the present invention, specifically, a cross-sectional view of the solid-state image sensor 100a cut along the through direction of the through electrode 600a. <FIG> is a diagram of the upper portion of the through electrode 600a according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode 600a cut along the through direction of the through electrode 600a. In <FIG>, the fixed charge film <NUM> is not illustrated for ease of understanding.

As illustrated in <FIG>, in a cross section of the solid-state image sensor 100a, a conductor 602a of the through electrode 600a according to the present invention has two branch portions (first branch portions) 602b split from the center axis (not illustrated in <FIG>) of the conductor 602a, at the upper portion (the end portion on the PD <NUM> side) of the through electrode 600a, more specifically, at the upper end (the end surface on the PD <NUM> side) of the through electrode 600a. In the present invention, the branch portion 602b is bend so as to draw an arc from the center axis.

Specifically, as illustrated in <FIG> which is an enlarged view of the through electrode 600a according to the present embodiment, the upper portion (the end portion on the PD <NUM> side) of the conductor 602a has a shape with a radius of curvature toward the light incident surface of the semiconductor substrate <NUM>. In other words, in the enlarged view above, the conductor 602a appears to have two branch portions 602b split so as to draw an arc from the center axis <NUM> of the conductor 602a. In the present embodiment, the radius of curvature r of the branch portion 602b is preferably <NUM> or more and <NUM> or less. That is, it is preferable that the radius of curvature r is set to such a value that can ensure that the insulating film <NUM> has a film thickness capable of suppressing short-circuiting to the semiconductor substrate <NUM> (specifically, the semiconductor region <NUM>) and also can ensure a large light incident surface on which light enters for the PDs <NUM> and <NUM>, in the same manner as in the first embodiment.

According to the present embodiment, at the region of the branch portion 602b that draws an arc, the distance L to the conductor 602a from an opening end 606c on the upper side of the through hole <NUM> covered with the insulating film <NUM> and the fixed charge film <NUM> (not illustrated) is uniform, compared with the foregoing first embodiment. In the present embodiment, therefore, even when a high voltage is applied to the insulating film <NUM> and the fixed charge film <NUM>, dielectric breakdown is less likely to occur at the branch portion 602b, thereby improving the withstand voltage (reliability) of the insulating film <NUM> and the fixed charge film <NUM>.

In the present invention, in a cross section of the solid-state image sensor 100a, the conductor 602a of the through electrode 600a according to the present embodiment has two branch portions (second branch portions) (not illustrated) split from the center axis <NUM> of the conductor 602a, at the lower portion (the end portion on the floating diffusion <NUM> side) of the through electrode 600a. More specifically, in the present embodiment, the conductor 602a has two branch portions, for example, at the lower end (the end surface on the floating diffusion <NUM> side) of the through electrode 600a. In the present invention, the branch portion at the lower portion of the through electrode 600a bent so as to draw an arc from the center axis <NUM>, similarly to the branch portion 602b. In such a case, the branch portion 602b at the upper portion of the through electrode 600a may have a radius of curvature r larger than that of the branch portion at the lower portion of the through electrode 600a.

In embodiments of the present disclosure, the through electrode <NUM> according to the foregoing first embodiment can be further modified. Referring to <FIG>, a through electrode 600b according to a third embodiment of the present disclosure will be described below. <FIG> is a diagram of the upper portion of the through electrode 600b according to the present embodiment, specifically, a partially enlarged view of a cross section of the through electrode 600b cut along the through direction of the through electrode 600b. In <FIG>, the fixed charge film <NUM> is not illustrated for ease of understanding.

As illustrated in <FIG>, in the above-noted cross section, a conductor 602c of the through electrode 600b according to the present embodiment has two branch portions (first branch portions) 602d split from the center axis of the conductor 602c, at the upper end (the end surface on the PD <NUM> side) of the through electrode 600a, in the same manner as in the foregoing third embodiment. In other words, the end portion on the PD <NUM> side of the conductor 602c according to the present embodiment has a shape expanding with a radius of curvature toward the light incident surface of the semiconductor substrate <NUM>. In addition, in the present embodiment, as illustrated in <FIG>, the conductor 602c further has a depression <NUM> positioned between the two branch portions 602d. That is, in the present embodiment, the conductor 602c is recessed at the center of the through hole <NUM> when the through hole <NUM> is viewed from above.

In the present embodiment, the depression <NUM> positioned between two branch portions 602d is provided to increase the contact area between the conductor 602c and the metal wiring <NUM> electrically connected to the through electrode 600b, thereby reducing the contact resistance between the conductor 602c and the metal wiring <NUM>.

In embodiments of the present disclosure, the PD <NUM> of the solid-state image sensor <NUM> according to the foregoing first embodiment can be further modified. Referring to <FIG>, a solid-state image sensor 100b according to a fourth embodiment of the present disclosure will be described below. <FIG> is a cross-sectional view of the solid-state image sensor 100b according to the present embodiment, specifically, a cross-sectional view of the solid-state image sensor 100b cut along the through direction of the through electrode <NUM>. In <FIG>, the solid-state image sensor 100b is illustrated such that the light incident surface on which light enters the solid-state image sensor 100b faces up.

In the present embodiment, as illustrated in <FIG>, a PD 200a provided above the semiconductor substrate <NUM> includes the upper electrode <NUM>, the photoelectric conversion film <NUM>, and the lower electrode <NUM>, similarly to the PD <NUM> according to the foregoing first embodiment. In the present embodiment, the PD 200a further includes an accumulation electrode <NUM> facing the upper electrode <NUM> with the photoelectric conversion film <NUM> and the insulating film <NUM> interposed therebetween. The accumulation electrode <NUM> is disposed at a distance from the lower electrode <NUM> and can be formed of, for example, a transparent conductor such as ITO and IZO, similarly to the upper electrode <NUM> and the lower electrode <NUM>.

In the PD 200a according to the present embodiment, wiring (not illustrated) is electrically connected individually to each of the lower electrode <NUM> and the accumulation electrode <NUM> so that a desired potential can be applied to each of the lower electrode <NUM> and the accumulation electrode <NUM> through the wiring. In the present embodiment, therefore, the potentials applied to the lower electrode <NUM> and the accumulation electrode <NUM> are controlled so that charge generated in the photoelectric conversion film <NUM> can be accumulated in the photoelectric conversion film <NUM> or the charge can be taken out at the floating diffusion <NUM>. In other words, the accumulation electrode <NUM> can function as an electrode for charge accumulation for drawing charge generated in the photoelectric conversion film <NUM> and accumulating the charge in the photoelectric conversion film <NUM> in accordance with the applied potential.

In the PD <NUM> according to the foregoing first embodiment, the charge generated by photoelectric conversion of the photoelectric conversion film <NUM> is directly accumulated in the floating diffusion <NUM> through the lower electrode <NUM> and the through electrode <NUM>. Because of such a mechanism, complete depletion in the photoelectric conversion film <NUM> is difficult. As a result, in the first embodiment, kTC noise (reset noise) of the solid-state image sensor <NUM> is large and random noise is worse, possibly leading to reduction in quality of captured images. On the other hand, in the present embodiment, the accumulation electrode <NUM> is provided so that, in operation of the PD 200a, while the charge generated by photoelectric conversion of each photoelectric conversion film <NUM> is accumulated in the photoelectric conversion film <NUM>, the charge reaching each lower electrode <NUM> is discharged to the outside system for resetting. In addition, in the operation, after resetting, the charge accumulated in each photoelectric conversion film <NUM> is transferred to the corresponding lower electrode <NUM>, and the charge transferred to the lower electrode <NUM> can be read out sequentially. In operation of the PD 200a, the resetting and readout operation as described above is repeatedly performed. That is, in the present embodiment, at the start of exposure of the solid-state image sensor 100b, complete depletion and charge removal in the floating diffusion <NUM> are facilitated. As a result, the present embodiment can suppress occurrence of the phenomenon of reduction in quality of captured images due to increased kTC noise of the solid-state image sensor 100b and worse random noise.

The solid-state imaging device <NUM> according to the foregoing embodiments of the present disclosure can be applied generally to electronic devices using imaging devices for image capturing units, such as imaging devices such as digital still cameras and camcorders, portable terminal devices having the image capturing function, and copiers including solid-state image sensors in image readers. Embodiments of the present disclosure can be further applied to robots, drones, automobiles, medical instruments (endoscopes), and the like that include the solid-state imaging device <NUM> described above. The solid-state imaging device <NUM> according to the present embodiment may be in the form of one chip or may be in the form of a module having the image capturing function including an imager and a signal processor or an optical system in one package. An example of an electronic device <NUM> including an imaging device <NUM> having the solid-state imaging device <NUM> will be described as a fifth embodiment of the present disclosure, with reference to <FIG> is a diagram illustrating an example of the electronic device <NUM> according to the present embodiment.

As illustrated in <FIG>, the electronic device <NUM> includes the imaging device <NUM>, an optical lens <NUM>, a shutter mechanism <NUM>, a drive circuit unit <NUM>, and a signal processing circuit unit <NUM>. The optical lens <NUM> focuses image light (incident light) from a subject onto an imaging plane of the imaging device <NUM>. Signal charges are thus accumulated for a certain period of time in the solid-state image sensors <NUM> of the solid-state imaging device <NUM> of the imaging device <NUM>. The shutter mechanism <NUM> is opened and closed to control a light radiation period and a light cut-off period for the imaging device <NUM>. The drive circuit unit <NUM> supplies a drive signal for controlling, for example, the signal transfer operation of the imaging device <NUM> and the shutter operation of the shutter mechanism <NUM> to the device and the mechanism. That is, the imaging device <NUM> performs signal transfer based on a drive signal (timing signal) supplied from the drive circuit unit <NUM>. The signal processing circuit unit <NUM> performs a variety of signal processing. For example, the signal processing circuit unit <NUM> outputs a picture signal subjected to signal processing to, for example, a storage medium (not illustrated) such as a memory or to a display (not illustrated).

As explained above, according to the embodiments and modifications of the present disclosure, the resistance value of the through electrode <NUM> can be kept low.

In the foregoing embodiments of the present disclosure, the solid-state image sensor <NUM> may be of a structure having two or three or more PDs <NUM> stacked above the semiconductor substrate <NUM>. In such a case, the through electrode <NUM> according to the present embodiment can be used, for example, as a through electrode for transferring the charge generated in the PD <NUM> stacked on the upper side, of two PDs <NUM> stacked above the semiconductor substrate <NUM>, to the floating diffusion <NUM> provided in the semiconductor substrate <NUM>.

In the foregoing embodiments of the present disclosure, the solid-state image sensor <NUM> in which the first conductivity type is P-type and the second conductivity type is N-type and electrons are used as signal charges has been described. However, embodiments of the present disclosure are not limited to such an example. For example, the present embodiment can be applied to the solid-state image sensor <NUM> in which the first conductivity type is N-type, the second conductivity type is P-type, and holes are signal charges.

In the foregoing embodiments of the present disclosure, the semiconductor substrate <NUM> is not necessarily a silicon substrate and may be any other substrate (for example, a silicon-on-insulator (SOI) substrate or a SiGe substrate). The semiconductor substrate <NUM> described above may have a semiconductor structure and the like formed on such a variety of substrates.

The solid-state image sensor <NUM> according to embodiments of the present disclosure is not limited to a solid-state image sensor that detects a distribution of the quantity of incident light of visible light to capture an image. For example, the present embodiment can be applied to a solid-state image sensor that captures a distribution of the quantity of incidence of infrared rays, X rays, particles, or the like as an image, and a solid-state image sensor (physical quantity distribution detecting device), such as finger print detecting sensor, that detects a distribution of any other physical quantities such as pressure and capacitance as an image.

The technique according to the present disclosure (the present technique) is applicable to a variety of products. For example, the technique according to the present disclosure may be applied to an endoscopic surgery system.

<FIG> is a diagram illustrating an example of the overall configuration of an endoscopic surgery system to which the technique according to the present disclosure (the present technique) is applicable.

<FIG> illustrates a situation in which an operator (doctor) <NUM> uses an endoscopic surgery system <NUM> to perform an operation on a patient <NUM> on a patient bed <NUM>. As illustrated in the drawing, the endoscopic surgery system <NUM> includes an endoscope <NUM>, other surgical instruments <NUM> such as an insufflation tube <NUM> and an energy treatment tool <NUM>, a support arm device <NUM> supporting the endoscope <NUM>, and a cart <NUM> carrying a variety of devices for endoscopic surgery.

The endoscope <NUM> includes a barrel <NUM> having a region of a predetermined length from its tip end to be inserted into the body cavity of the patient <NUM>, and a camera head <NUM> connected to the base end of the barrel <NUM>. In the example illustrated in the drawing, the endoscope <NUM> is a rigid borescope having a rigid barrel <NUM>. However, the endoscope <NUM> may be configured as a soft borescope having a soft barrel.

The tip end of the barrel <NUM> has an opening having an objective lens fitted therein. A light source device <NUM> is connected to the endoscope <NUM>. Light generated by the light source device <NUM> is propagated to the tip end of the barrel through a light guide extending inside the barrel <NUM> and irradiates an observation target in the body cavity of the patient <NUM> through the objective lens. The endoscope <NUM> may be a forward-viewing endoscope or may be a forward-oblique viewing endoscope or a side-viewing endoscope.

An optical system and an image sensor are provided inside the camera head <NUM>. Reflected light (observation light) from an observation target is collected by the optical system onto the image sensor. The observation light is converted to electricity by the image sensor to generate an electrical signal corresponding to the observation light, that is, an image signal corresponding to an observation image. The image signal is transmitted as RAW data to a camera control unit (CCU) <NUM>.

The CCU <NUM> is configured with a central processing unit (CPU), a graphics processing unit (GPU), or the like to centrally control the operation of the endoscope <NUM> and a display device <NUM>. The CCU <NUM> receives an image signal from the camera head <NUM> and performs a variety of image processing on the image signal, for example, a development process (demosaicing) for displaying an image based on the image signal.

The display device <NUM> displays an image based on the image signal subjected to image processing by the CCU <NUM>, under the control of the CCU <NUM>.

The light source device <NUM> is configured with a light source such as a light emitting diode (LED) and supplies the endoscope <NUM> with radiation light in imaging a surgery site.

An input device <NUM> is an input interface with the endoscopic surgery system <NUM>. The user can input a variety of information and instructions to the endoscopic surgery system <NUM> through the input device <NUM>. For example, the user inputs an instruction to change the imaging conditions by the endoscope <NUM> (the kind of radiation light, magnification, focal length, etc.).

A treatment tool control device <NUM> controls actuation of the energy treatment tool <NUM> for cauterization of tissues, incision, or sealing of blood vessels. An insufflator <NUM> feeds gas into the body cavity through the insufflation tube <NUM> to insufflate the body cavity of the patient <NUM> in order to ensure the field of view with the endoscope <NUM> and ensure a working space for the operator. A recorder <NUM> is a device capable of recording a variety of information on surgery. A printer <NUM> is a device capable of printing a variety of information on surgery in a variety of forms such as text, image, or graph.

The light source device <NUM> that supplies the endoscope <NUM> with radiation light in imaging a surgery site can be configured with, for example, a white light source such as an LED, a laser light source, or a combination thereof. When a white light source is configured with a combination of RGB laser light sources, the output power and the output timing of each color (each wavelength) can be controlled accurately, and, therefore, the white balance of the captured image can be adjusted in the light source device <NUM>. In this case, an observation target is irradiated time-divisionally with laser light from each of the RGB laser light sources, and actuation of the image sensor in the camera head <NUM> is controlled in synchronization with the radiation timing, whereby an image corresponding to each of R, G, and B can be captured time-divisionally. According to this method, a color image can be obtained even without color filters in the image sensor.

The actuation of the light source device <NUM> may be controlled such that the intensity of output light is changed every certain time. In synchronization with the timing of changing the intensity of light, the actuation of the image sensor in the camera head <NUM> is controlled to acquire images time-divisionally, and the images are combined to generate an image with a high dynamic range free from blocked-up shadows and blown out highlights.

The light source device <NUM> may be configured to supply light in a predetermined wavelength band corresponding to specific light observation. In specific light observation, for example, narrow band imaging is performed, which uses the wavelength dependency of light absorption in body tissues and applies light in a narrow band, compared with radiation light (that is, white light) in normal observation, to capture an image of predetermined tissues such as blood vessels in the outermost surface of mucosa. Alternatively, in specific light observation, fluorescence observation may be performed in which an image is acquired by fluorescence generated by radiation of excitation light. In fluorescence observation, for example, excitation light is applied to body tissues and fluorescence from the body tissues is observed (autofluorescence imaging), or a reagent such as indocyanine green (ICG) is locally injected to body tissues and excitation light corresponding to the fluorescence wavelength of the reagent is applied to the body tissues to obtain a fluorescence image. The light source device <NUM> may be configured to supply narrow-band light and/or excitation light corresponding to such specific light observation.

<FIG> is a block diagram illustrating an example of the functional configuration of the camera head <NUM> and the CCU <NUM> illustrated in <FIG>.

The camera head <NUM> includes a lens unit <NUM>, an imager <NUM>, a driver <NUM>, a communication module <NUM>, and a camera head controller <NUM>. The CCU <NUM> includes a communication module <NUM>, an image processor <NUM>, and a controller <NUM>. The camera head <NUM> and the CCU <NUM> are connected to communicate with each other through a transmission cable <NUM>.

The lens unit <NUM> is an optical system provided at a connection portion to the barrel <NUM>. Observation light taken in from the tip end of the barrel <NUM> is propagated to the camera head <NUM> and enters the lens unit <NUM>. The lens unit <NUM> is configured with a combination of a plurality of lenses including a zoom lens and a focus lens.

The imager <NUM> is configured with an image sensor. The imager <NUM> may be configured with one image sensor (called single sensor-type) or a plurality of image sensors (called multi sensor-type). When the imager <NUM> is a multi-sensor construction, for example, image signals corresponding to R, G, and B may be generated by image sensors and combined to produce a color image. Alternatively, the imager <NUM> may have a pair of image sensors for acquiring image signals for right eye and for left eye corresponding to three-dimensional (3D) display. The 3D display enables the operator <NUM> to more accurately grasp the depth of living tissues in a surgery site. When the imager <NUM> is a multi-sensor construction, several lines of lens units <NUM> may be provided corresponding to the image sensors.

The imager <NUM> is not necessarily provided in the camera head <NUM>. For example, the imager <NUM> may be provided immediately behind the objective lens inside the barrel <NUM>.

The driver <NUM> is configured with an actuator and moves the zoom lens and the focus lens of the lens unit <NUM> by a predetermined distance along the optical axis under the control of the camera head controller <NUM>. The magnification and the focal point of a captured image by the imager <NUM> thus can be adjusted as appropriate.

The communication module <NUM> is configured with a communication device for transmitting/receiving a variety of information to/from the CCU <NUM>. The communication module <NUM> transmits an image signal obtained from the imager <NUM> as RAW data to the CCU <NUM> through the transmission cable <NUM>.

The communication module <NUM> receives a control signal for controlling actuation of the camera head <NUM> from the CCU <NUM> and supplies the received signal to the camera head controller <NUM>. The control signal includes, for example, information on imaging conditions, such as information specifying a frame rate of the captured images, information specifying an exposure value in imaging, and/or information specifying a magnification and a focal point of the captured image.

The image conditions such as frame rate, exposure value, magnification, and focal point may be specified as appropriate by the user or may be automatically set by the controller <NUM> of the CCU <NUM> based on the acquired image signal. In the latter case, the endoscope <NUM> is equipped with an auto exposure (AE) function, an auto focus (AF) function, and an auto white balance (AWB) function.

The camera head controller <NUM> controls actuation of the camera head <NUM>, based on a control signal received from the CCU <NUM> through the communication module <NUM>.

The communication module <NUM> is configured with a communication device for transmitting/receiving a variety of information to/from the camera head <NUM>. The communication module <NUM> receives an image signal transmitted from the camera head <NUM> through the transmission cable <NUM>.

The communication module <NUM> transmits a control signal for controlling actuation of the camera head <NUM> to the camera head <NUM>. The image signal and the control signal can be transmitted via electrical communication or optical communication.

The image processor <NUM> performs a variety of image processing on the image signal that is RAW data transmitted from the camera head <NUM>.

The controller <NUM> performs a variety of control on imaging of a surgery site and the like by the endoscope <NUM> and display of a captured image obtained by imaging of a surgery site and the like. For example, the controller <NUM> generates a control signal for controlling actuation of the camera head <NUM>.

The controller <NUM> displays a captured image visualizing a surgery site and the like on the display device <NUM>, based on the image signal subjected to image processing by the image processor <NUM>. In doing so, the controller <NUM> may recognize a variety of objects in the captured image using a variety of image recognition techniques. For example, the controller <NUM> detects the shape of edge, color, and the like of an object included in the captured image to recognize a surgical instrument such as forceps, a specific living body site, bleeding, and mist in use of the energy treatment tool <NUM>. When displaying the captured image on the display device <NUM>, the controller <NUM> may use the recognition result to superimpose a variety of surgery assisting information on the image of the surgery site. The surgery assisting information superimposed and presented to the operator <NUM> can alleviate burden on the operator <NUM> or ensure the operator <NUM> to proceed surgery.

The transmission cable <NUM> connecting the camera head <NUM> and the CCU <NUM> is an electrical signal cable corresponding to communication of electrical signals, an optical fiber corresponding to optical communication, or a composite cable thereof.

In the example illustrated in the drawing, the transmission cable <NUM> is used for wired communication. However, communication between the camera head <NUM> and the CCU <NUM> may be wireless.

An example of the endoscopic surgery system to which the technique according to the present disclosure is applicable has been described above. The technique according to the present disclosure may be applicable to, for example, the endoscope <NUM>, the imager <NUM> in the camera head <NUM>, and the image processor <NUM> of the CCU <NUM> in the configuration described above. For example, the solid-state imaging device <NUM> illustrated in <FIG> can be applied to the endoscope <NUM>, the imager <NUM>, the image processor <NUM>, and the like. When the technique according to the present disclosure is applied to the endoscope <NUM>, the imager <NUM>, the image processor <NUM>, and the like, a sharper surgery site image can be obtained to ensure that the operator examines the surgery site.

Although the endoscopic surgery system has been described here by way of example, the technique according to the present disclosure may be applied to, for example, a microscopic surgery system.

The technique according to the present disclosure (the present technique) is applicable to a variety of products. For example, the technique according to the present disclosure may be implemented as a device mounted on any type of movable bodies, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, vessels and ships, and robots.

<FIG> is a block diagram illustrating an example of the overall configuration of a vehicle control system that is an example of a movable body control system to which the technique according to the present disclosure is applicable.

A vehicle control system <NUM> includes a plurality of electronic control units connected through a communication network <NUM>. In the example illustrated in <FIG>, the vehicle control system <NUM> includes a drive control unit <NUM>, a body control unit <NUM>, a vehicle exterior information detection unit <NUM>, a vehicle interior information detection unit <NUM>, and a central control unit <NUM>. As a functional configuration of the central control unit <NUM>, a microcomputer <NUM>, a sound image output module <NUM>, and an in-vehicle network I/F (interface) <NUM> are illustrated.

The drive control unit <NUM> controls operation of devices related to a drive system of a vehicle in accordance with a variety of computer programs. For example, the drive control unit <NUM> functions as a control device for a drive force generating device for generating drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating braking force of the vehicle.

The body control unit <NUM> controls operation of a variety of devices installed in the vehicle body in accordance with a variety of computer programs. For example, the body control unit <NUM> functions as a control device for a keyless entry system, a smart key system, a power window device, or a variety of lamps such as head lamps, rear lamps, brake lamps, turn signals, and fog lamps. In this case, the body control unit <NUM> may receive radio waves transmitted from a portable device alternative to a key or signals from a variety of switches. The body control unit <NUM> accepts input of the radio waves or signals and controls a door lock device, a power window device, a lamp, and the like of the vehicle.

The vehicle exterior information detection unit <NUM> detects information on the outside of the vehicle equipped with the vehicle control system <NUM>. For example, an imager <NUM> is connected to the vehicle exterior information detection unit <NUM>. The vehicle exterior information detection unit <NUM> allows the imager <NUM> to capture an image of the outside of the vehicle and receives the captured image. The vehicle exterior information detection unit <NUM> may perform an object detection process or a distance detection process for persons, vehicles, obstacles, signs, or characters on roads, based on the received image.

The imager <NUM> is an optical sensor that receives light and outputs an electrical signal corresponding to the quantity of received light of the light. The imager <NUM> may output an electrical signal as an image or output as information on a measured distance. Light received by the imager <NUM> may be visible light or invisible light such as infrared rays.

The vehicle interior information detection unit <NUM> detects information on the inside of the vehicle. The vehicle interior information detection unit <NUM> is connected to, for example, a driver state detector <NUM> that detects a state of the driver. The driver state detector <NUM> includes, for example, a camera for taking an image of the driver, and the vehicle interior information detection unit <NUM> may calculate the degree of fatigue or the degree of concentration of the driver or may determine whether the driver falls asleep, based on detection information input from the driver state detector <NUM>.

The microcomputer <NUM> can compute a control target value for the drive force generating device, the steering mechanism, or the braking device, based on information on the inside and outside of the vehicle acquired by the vehicle exterior information detection unit <NUM> or the vehicle interior information detection unit <NUM>, and output a control command to the drive control unit <NUM>. For example, the microcomputer <NUM> can perform coordination control for the purpose of function implementation of advanced driver assistance systems (ADAS), including collision avoidance or shock mitigation of the vehicle, car-following drive based on the distance between vehicles, vehicle speed-keeping drive, vehicle collision warning, and lane departure warning.

The microcomputer <NUM> can perform coordination control for the purpose of, for example, autonomous driving, in which the drive force generating device, the steering mechanism, or the braking device is controlled based on information on the surroundings of the vehicle acquired by the vehicle exterior information detection unit <NUM> or the vehicle interior information detection unit <NUM> to enable autonomous driving without depending on the operation by the driver.

The microcomputer <NUM> can output a control command to the body control unit <NUM>, based on information on the outside of the vehicle acquired by the vehicle exterior information detection unit <NUM>. For example, the microcomputer <NUM> can perform coordination control for the antidazzle purpose, for example, by controlling the head lamps in accordance with the position of a vehicle ahead or an oncoming vehicle detected by the vehicle exterior information detection unit <NUM> to switch high beams to low beams.

The sound image output module <NUM> transmits an output signal of at least one of sound and image to an output device capable of visually or aurally giving information to a passenger in the vehicle or the outside of the vehicle. In the example in <FIG>, an audio speaker <NUM>, a display <NUM>, and an instrument panel <NUM> are illustrated as the output device. The display <NUM> may include, for example, at least one of an on-board display and a head-up display.

<FIG> is a diagram illustrating an example of the installation position of the imager <NUM>.

In <FIG>, a vehicle <NUM> has imagers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> as the imager <NUM>.

The imagers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are provided, for example, at positions such as front nose, side mirrors, rear bumper, back door of the vehicle <NUM>, and an upper portion of the front glass inside the vehicle. The imager <NUM> provided at the front nose and the imager <NUM> provided at the upper portion of the front glass inside the vehicle mainly acquire an image in front of the vehicle <NUM>. The imagers <NUM> and <NUM> provided at the side mirrors mainly acquire images on the sides of the vehicle <NUM>. The imager <NUM> provided at the rear bumper or the back door mainly acquires an image behind the vehicle <NUM>. The images ahead acquired by the imagers <NUM> and <NUM> are mainly used for detecting a vehicle ahead, pedestrians, obstacles, traffic signs, road signs, or traffic lanes, for example.

<FIG> illustrates an example of the imaging ranges of the imagers <NUM> and <NUM>. An imaging range <NUM> indicates an imaging range of the imager <NUM> provided at the front nose, imaging ranges <NUM> and <NUM> indicate the imaging ranges of the imagers <NUM> and <NUM> provided at the side mirrors, and an imaging range <NUM> indicates the imaging range of the imager <NUM> provided at the rear bumper or the back door. For example, a bird's eye view of the vehicle <NUM> viewed from above can be obtained by superimposing image data captured by the imagers <NUM> and <NUM>.

At least one of the imagers <NUM> and <NUM> may have a function of acquiring distance information. For example, at least one of the imagers <NUM> and <NUM> may be a stereo camera including a plurality of image sensors or may be an image sensor having a pixel for phase difference detection.

For example, the microcomputer <NUM> can obtain the distance to a three-dimensional object within the imaging range <NUM> or <NUM> and a temporal change of this distance (relative speed to the vehicle <NUM>), based on distance information obtained from the imager <NUM> or <NUM>, to specifically extract a three-dimensional object closest to the vehicle <NUM> on the path of travel and traveling at a predetermined speed (for example, <NUM>/h or more) in substantially the same direction as the vehicle <NUM>, as a vehicle ahead. In addition, the microcomputer <NUM> can preset a distance between vehicles to be kept in front of a vehicle ahead and perform, for example, automatic braking control (including car-following stop control) and automatic speed-up control (including car-following startup control). In this way, coordination control can be performed, for example, for the purpose of autonomous driving in which the vehicle runs autonomously without depending on the operation by the driver.

For example, the microcomputer <NUM> can classify three-dimensional object data on a three-dimensional object into two-wheel vehicle, standard-sized vehicle, heavy vehicle, pedestrian, utility pole, or any other three-dimensional object, based on the distance information obtained from the imager <NUM> or <NUM>, and can use the extracted data for automatic avoidance of obstacles. For example, the microcomputer <NUM> identifies an obstacle in the surroundings of the vehicle <NUM> as an obstacle visible to the driver of the vehicle <NUM> or as an obstacle hardly visible. The microcomputer <NUM> then determines a collision risk indicating the degree of risk of collision with each obstacle and, when the collision risk is equal to or higher than a setting value and there is a possibility of collision, outputs an alarm to the driver through the audio speaker <NUM> or the display <NUM>, or performs forced deceleration or avoidance steering through the drive control unit <NUM>, thereby implementing drive assistance for collision avoidance.

At least one of the imagers <NUM> and <NUM> may be an infrared camera that detects infrared rays. For example, the microcomputer <NUM> can recognize a pedestrian by determining whether a pedestrian exists in the captured image by the imager <NUM> or <NUM>. Such recognition of pedestrians is performed, for example, through the procedure of extracting feature points in the captured image by the imager <NUM> or <NUM> serving as an infrared camera and the procedure of performing pattern matching with a series of feature points indicating the outline of an object to determine whether the object is a pedestrian. When the microcomputer <NUM> determines that a pedestrian exists in the captured image by the imager <NUM> or <NUM> and recognizes a pedestrian, the sound image output module <NUM> controls the display <NUM> such that a rectangular outline for highlighting the recognized pedestrian is superimposed. The sound image output module <NUM> may control the display <NUM> such that an icon indicating a pedestrian appears at a desired position.

Claim 1:
A solid-state image sensor comprising:
a semiconductor substrate (<NUM>);
a charge accumulator (<NUM>) disposed in the semiconductor substrate (<NUM>) and configured to accumulate charge;
a photoelectric converter (<NUM>) disposed above the semiconductor substrate (<NUM>) and configured to convert light to charge; and
a through electrode (<NUM>) passing through the semiconductor substrate (<NUM>) and electrically connecting the charge accumulator (<NUM>) with the photoelectric converter (<NUM>), wherein
at an end portion on the photoelectric converter (<NUM>) side of the through electrode (<NUM>),
a cross-sectional area of a conductor (<NUM>) positioned at a center of the through electrode (<NUM>) in a cut section orthogonal to a through direction of the through electrode (<NUM>) gradually increases toward the photoelectric converter (<NUM>) along the through direction, wherein
in a cross section of the through electrode (<NUM>) cut along the through direction,
the end portion on the photoelectric converter side of the conductor (<NUM>) has two first branch portions (602b) split from a center axis of the conductor (<NUM>),
characterised in that
each of the first branch portions (602b) is bent so as to draw an arc from the center axis.