LIGHT DETECTION DEVICE AND ELECTRONIC DEVICE

A technique for achieving spectral separation. A light detection device includes a semiconductor layer with a photoelectric conversion unit is provided for each of the pixels, and an optical filter layer on a light incident surface side that includes a first filter part and a second filter part for each of the pixels. Each of the first and second filter parts includes: a first metal film on the light incident surface side of the semiconductor layer; a first dielectric film and a second dielectric film having different refractive indices that are arranged in a thickness direction of the semiconductor layer side by side, on a side of the first metal film opposite the semiconductor layer; and a second metal film on a side of the dielectric films opposite the first metal film. A ratio of thicknesses between the dielectric films is different in the different filter parts.

TECHNICAL FIELD

The present technique (the technique according to the present disclosure) relates to a light detection device, and particularly relates to a technique useful for applications in a light detection device having an optical filter layer and an electronic device provided with the same.

BACKGROUND ART

Light detection devices, such as solid-state image capturing devices and rangefinding devices, include an optical filter layer that guides incident light to a photoelectric conversion region in a semiconductor layer. PTL 1 discloses a color filter layer including a filter part constituted by a thermosetting resin to which a pigment is added.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

However, in a color filter layer constituted by a resin to which a pigment is added, the transmittance is determined by the properties of the material, and it has therefore been difficult to achieve spectral separation, where light is divided into a variety of wavelength bands.

An object of the present technique is to provide a technique capable of achieving spectral separation.

Solution to Problem

(1) A light detection device according to one aspect of the present technique includes:a semiconductor layer in which a photoelectric conversion unit is provided for each of pixels; andan optical filter layer provided on a light incidence surface side of the semiconductor layer,whereinthe optical filter layer includes a first filter part and a second filter part, each provided for each of the pixels,each of the first and second filter parts includes:a first metal film provided on the light incidence surface side of the semiconductor layer;a first dielectric film and a second dielectric film which have different refractive indices and which are arranged in a thickness direction of the semiconductor layer side by side, on a side of the first metal film opposite from a side on which the semiconductor layer is located; anda second metal film provided on a side of the first and second dielectric films opposite from a side on which the first metal film is located, anda ratio of thicknesses of the first dielectric film and the second dielectric film is different in the first filter part and in the second filter part.(2) A light detection device according to another aspect of the present technique includes:a semiconductor layer in which a photoelectric conversion unit is provided; andan optical filter layer provided on a light incidence surface side of the semiconductor layer,whereinthe optical filter layer includes:a first metal film provided on the light incidence surface side of the semiconductor layer;a first dielectric film and a second dielectric film which have different refractive indices and which are arranged in a thickness direction of the semiconductor layer side by side, on a side of the first metal film opposite from a side on which the semiconductor layer is located;a second metal film provided on a side of the first and second dielectric films opposite from a side on which the first metal film is located; anda light absorption film provided between the first dielectric film and the second dielectric film.(3) An electronic device according to another aspect of the present technique includes:the light detection device;an optical lens that forms an image of image light from a subject on an image capturing plane of the light detection device; anda signal processing circuit that performs signal processing on a signal output from the light detection device.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present technique will be described hereinafter with reference to the drawings.

In the descriptions of the drawings referred to in the following, identical or similar parts will be given identical or similar reference signs. However, it should be noted that the drawings are schematic, and the relationships between thicknesses and planar dimensions, the ratios of thicknesses of layers, and the like are different from the actual ratios, thicknesses, and the like. Therefore, specific thicknesses and dimensions should be determined in light of the following descriptions.

In addition, it goes without saying that the drawings also include parts having dimensional relationships and ratios different from those in other drawings. Furthermore, the effects described in the present specification are merely exemplary and not intended to be limiting, and other effects may be provided as well.

The following embodiments exemplify devices, methods, and the like for embodying the technical spirit of the present technique, and the configurations are not limited to those described below. In other words, the technical spirit of the present technique can be modified in various ways within the technical scope set forth in the claims.

In addition, it is to be understood that definitions of directions such as “up-down” in the following descriptions are merely definitions provided for the sake of brevity and are not intended to limit the technical spirit of the present technique. For example, it is obvious that when an object is observed after being rotated by 90 degrees, “up-down” is transformed into and interpreted as “left-right”, and when an object is observed after being rotated by 180 degrees, “up-down” is interpreted as being inverted.

The following embodiments describe a case where as the conductivity types of semiconductors, a first conductivity type is p-type and a second conductivity type is n-type. However, the reverse relationship may be selected for the conductivity types, such that the first conductivity type is n-type and the second conductivity type is p-type.

Furthermore, in the following embodiments, a first direction and a second direction orthogonal to each other in a two-dimensional plane are defined as an X direction and a Y direction, respectively, and a third direction orthogonal to the two-dimensional plane is defined as an X direction. Finally, in the following embodiments, a thickness direction of a semiconductor layer20(described later) will be defined as being a Z direction.

First Embodiment

A first embodiment will describe an example in which the present technique is applied to a solid-state image capturing device that is a backside-illuminated Complementary Metal Oxide Semiconductor (CMOS) image sensor, serving as a light detection device.

<<Overall Configuration of Solid-State Image Capturing Device>>

The overall configuration of a solid-state image capturing device1A will be described first. As illustrated inFIG.1, the solid-state image capturing device1A according to the first embodiment of the present technique is constituted mainly by a semiconductor chip2, which has a square two-dimensional planar shape when viewed in plan view. In other words, the solid-state image capturing device1A is installed on the semiconductor chip2, and the semiconductor chip2can therefore be regarded as the solid-state image capturing device1A. As illustrated inFIG.48, the solid-state image capturing device1A (101) takes in image light from a subject (incident light106) through an optical lens102, converts the amount of incident light106formed on an image capturing plane into electrical signals on a pixel-by-pixel basis, and outputs the electrical signals as pixel signals.

As illustrated inFIG.1, the semiconductor chip2on which the solid-state image capturing device1A is installed includes a square pixel array part2A provided in a central area and a peripheral part2B provided outside the pixel array part2A so as to surround the pixel array part2A, in the two-dimensional plane including the X direction and the Y direction orthogonal to each other. The semiconductor chip2is formed by subdividing a semiconductor wafer, which includes the semiconductor layer20(described later), into each of chip formation regions in a manufacturing process. Accordingly, the configuration of the solid-state image capturing device1A described below is generally the same in the wafer state prior to subdividing the semiconductor wafer. In other words, the present technique can be applied in both a semiconductor chip state and a semiconductor wafer state.

The pixel array part2A is a light-receiving surface that receives the light focused by the optical lens (optical system)102illustrated inFIG.48, for example. In the pixel array part2A, a plurality of pixels (sensor pixels)3are arranged in a matrix in the two-dimensional plane including the X direction and the Y direction. In other words, the pixels3are arranged in a repeating manner in both the X direction and the Y direction, which are orthogonal to each other in the two-dimensional plane. As illustrated inFIG.4, the plurality of pixels3include a pixel (sensor pixel)3a, a pixel (sensor pixel)3b, and a pixel (sensor pixel)3c.

As illustrated inFIG.1, a plurality of bonding pads14are disposed in the peripheral part2B. Each of the plurality of bonding pads14, for example, is disposed along one of the four sides of the two-dimensional plane of the semiconductor chip2. Each of the plurality of bonding pads14functions as an input/output terminal that electrically connects the semiconductor chip2to an external device.

The semiconductor chip2includes a logic circuit13, which is illustrated inFIG.2. As illustrated inFIG.2, the logic circuit13includes a vertical drive circuit4, column signal processing circuits5, a horizontal drive circuit6, an output circuit7, a control circuit8, and the like. The logic circuit13is constituted by a Complementary MOS (CMOS) circuit having an n-channel conductive Metal Oxide Semiconductor Field Effect Transistor (MOSFET) and a p-channel conductive MOSFET as field effect transistors, for example.

The vertical drive circuit4is constituted by a shift register, for example. The vertical drive circuit4selects a desired pixel drive line10in sequence, supplies a pulse for driving the pixels3to the selected pixel drive line10, and drives respective pixels3in unit of rows. In other words, the vertical drive circuit4sequentially performs selective scanning of the pixels3of the pixel array part2A in units of rows in a vertical direction, and supplies pixel signals from the pixels3, which are based on signal charges generated in accordance with the amount of light received by photoelectric conversion units (photoelectric conversion elements) of the pixels3, to the column signal processing circuits5through vertical signal lines11.

The column signal processing circuits5are provided, for example, for corresponding columns of pixels3, and perform signal processing such as noise removal for each pixel column on a signal output from the pixels3corresponding to one row. For example, the column signal processing circuit5performs signal processing such as correlated double sampling (CDS) and analog-digital (AD) conversion for removing pixel-specific fixed pattern noise.

The horizontal drive circuit6is constituted by a shift register, for example. The horizontal drive circuit6sequentially selects each column signal processing circuit5by sequentially outputting a horizontal scanning pulse to the column signal processing circuit5, and outputs a pixel signal on which signal processing has been performed from each column signal processing circuit5to a horizontal signal line12.

The output circuit7performs signal processing on the pixel signals sequentially supplied from the respective column signal processing circuits5through the horizontal signal line12, and outputs the resulting pixel signals. Examples of the signal processing which may be used include buffering, black level adjustment, column variation correction, various types of digital signal processing, and the like, for example.

The control circuit8generates a clock signal or a control signal as a reference for operations of the vertical drive circuit4, the column signal processing circuit5, the horizontal drive circuit6, and the like based on a vertical synchronization signal, a horizontal synchronization signal, and a master clock signal. The control circuit8then outputs the generated clock signal or control signal to the vertical drive circuit4, the column signal processing circuits5, the horizontal drive circuit6, and the like.

<Circuit Configuration of Pixel>

As illustrated inFIG.3, each pixel3of the plurality of pixels3includes a photoelectric conversion region21and a readout circuit15. The photoelectric conversion region21includes a photoelectric conversion unit25, a transfer transistor TR serving as a pixel transistor, and a floating diffusion region FD serving as a charge holding unit. The readout circuit15is electrically connected to the floating diffusion region FD of the photoelectric conversion region21. Although the first embodiment will describe a circuit configuration in which one readout circuit15is assigned to one pixel3as an example, the configuration is not limited thereto, and a circuit configuration in which one readout circuit15is shared by a plurality of pixels3may be used.

The photoelectric conversion unit25illustrated inFIG.3is constituted by, for example, a pn junction photodiode (PD), and generates a signal charge according to an amount of light received. The photoelectric conversion unit25is electrically connected to the source region of the transfer transistor TR on the cathode side, and to a reference potential line (e.g., ground) on the anode side.

The transfer transistor TR illustrated inFIG.3transfers the signal charge resulting from the photoelectric conversion by the photoelectric conversion unit25to the floating diffusion region FD. The source region of a transfer transistor RTL is electrically connected to the cathode side of the photoelectric conversion unit25, and the drain region of the transfer transistor TR is electrically connected to the floating diffusion region FD. The gate electrode of the transfer transistor TR is electrically connected to a transfer transistor drive line of the pixel drive line10(seeFIG.2).

The floating diffusion region FD illustrated inFIG.3temporarily holds (accumulates) the signal charge transferred from the photoelectric conversion unit25through the transfer transistor TR.

The photoelectric conversion region21including the photoelectric conversion unit25, the transfer transistor TR, and the floating diffusion region FD is provided in the semiconductor layer20(described later; seeFIG.4).

The readout circuit15illustrated inFIG.3reads out the signal charge held in the floating diffusion region FD and outputs a pixel signal based on this signal charge. Although not limited thereto, the readout circuit15includes, for example, an amplifying transistor AMP, a selection transistor SEL, and a reset transistor RST as pixel transistors. Each of the transistors (AMP, SEL, and RST) and the transfer transistor TR described above is constituted by a MOSFET having, for example, a gate insulating film formed from a silicon oxide (SiO2) film, a gate electrode, and a pair of main electrode regions functioning as a source region and a drain region, as a field effect transistor. The transistor may be a metal insulator semiconductor FET (MISFET) whose gate insulating film is a silicon nitride (a Si3N4) film or a layered film including a silicon nitride film, a silicon oxide film, or the like.

As illustrated inFIG.3, the amplifying transistor AMP has a source region electrically connected to a drain region of the selection transistor SEL, and a drain region electrically connected to a power source line Vdd and a drain region of the reset transistor RST. The gate electrode of the amplifying transistor AMP is electrically connected to the floating diffusion region FD and a source region of the reset transistor RST.

The selection transistor SEL has a source electrically connected to the vertical signal line11(VSL), and a drain region electrically connected to a source region of the amplifying transistor AMP. The gate electrode of the selection transistor SEL is electrically connected to a selection transistor drive line of the pixel drive line10(seeFIG.2).

The reset transistor RST has a source region electrically connected to the floating diffusion region FD and the gate electrode of the amplifying transistor AMP, and a drain region electrically connected to the power source line Vdd and the drain region of the amplifying transistor AMP. The gate electrode of the reset transistor RST is electrically connected to a reset transistor drive line of the pixel drive line10(seeFIG.2).

When the transfer transistor TR is turned on, the transfer transistor TR transfers the signal charge generated by the photoelectric conversion unit25to the floating diffusion region FD.

When the reset transistor RST is turned on, the reset transistor RST resets the potential of the floating diffusion region FD (the signal charge) to the potential of the power source line Vdd. The selection transistor SEL controls the timing at which the pixel signal is output from the readout circuit15.

The amplifying transistor AMP generates, as the pixel signal, a signal at a voltage based on the level of the signal charge held in the floating diffusion region FD. The amplifying transistor AMP constitutes a source-follower amplifier, and outputs a pixel signal at a voltage based on the level of the signal charge generated by the photoelectric conversion unit25. When the selection transistor SEL is turned on, the amplifying transistor AMP amplifies the potential of the floating diffusion region FD and outputs a voltage based on that potential to the column signal processing circuit5over the vertical signal line11(VSL).

During the operation of the solid-state image capturing device1A according to the first embodiment, the signal charge generated by the photoelectric conversion unit25of the pixel3is held (accumulated) in the floating diffusion region FD via the transfer transistor TR of the pixel3. The signal charge held in the floating diffusion region FD is then read out by the readout circuit15and applied to the gate electrode of the amplifying transistor AMP of the readout circuit15. A horizontal line selection control signal is provided from the vertical shift register to the gate electrode of the selection transistor SEL of the readout circuit15. Then, when the selection control signal is set to high (H) level, the selection transistor SEL becomes conductive, and a current corresponding to the potential of the floating diffusion region FD, amplified by the amplifying transistor AMP, flows in the vertical signal line11. Additionally, when a reset control signal applied to the gate electrode of the reset transistor RST of the readout circuit15is set to high (H) level, the reset transistor RST becomes conductive and resets the signal charge accumulated in the floating diffusion region FD.

Note that the selection transistor SEL may be omitted as necessary. When the selection transistor SEL is omitted, the source region of the amplifying transistor AMP is electrically connected to the vertical signal line11(VSL).

<<Specific Configuration of Solid-State Image Capturing Device>>

The specific configuration of the semiconductor chip2(the solid-state image capturing device1A) will be described next with reference toFIGS.4to6.

FIG.4is a longitudinal cross-sectional view schematically illustrating the longitudinal cross-sectional structure of the pixel array part2A of the solid-state image capturing device1A, and illustrates five pixels as an example.FIG.5is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.4, and illustrates pixels3aand3b, which are the second and third pixels of the five pixels3inFIG.4counted from the left side, as an example.FIG.6is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.4, and illustrates pixels3band3c, which are the third and fourth pixels of the five pixels3inFIG.4counted from the left side, as an example.

As illustrated inFIG.4, the semiconductor chip2includes the semiconductor layer20, which has a first surface S1and a second surface S2located on opposite sides from each other in the thickness direction (the Z direction), and provided with the photoelectric conversion region21for each pixel3; and an optical filter layer40provided on a light incidence surface side, which is the second surface S2side of the semiconductor layer20. The semiconductor chip2further includes an insulating layer35provided between the semiconductor layer20and the optical filter layer40, and an insulating layer45provided on the side of the optical filter layer40opposite from the side on which the semiconductor layer20is located. The semiconductor chip2further includes a multilayer wiring layer30disposed on the first surface S1side of the semiconductor layer20, and a support substrate34provided on the side of the multilayer wiring layer30opposite from the side on which the semiconductor layer20is located.

As illustrated inFIG.4, the semiconductor layer20is provided with an isolation region23extending in the thickness direction of the semiconductor layer20(the Z direction), and a plurality of the photoelectric conversion regions21partitioned by the isolation region23for each pixel3. The photoelectric conversion regions21among the plurality of photoelectric conversion regions21are, when viewed in plan view, adjacent to each other with the isolation region23located therebetween.

The isolation region23extends from the first surface S1side to the second surface S2side of the semiconductor layer20, and electrically and optically separates the photoelectric conversion regions21adjacent to each other. Although not limited thereto, the isolation region23has an isolation structure in which an insulating film is embedded in a trench part of the semiconductor layer20, for example.

A Si substrate, a SiGe substrate, an InGaAs substrate, or the like can be used as the semiconductor layer20. In the first embodiment, a p-type semiconductor substrate constituted by monocrystalline silicon, for example, is used as the semiconductor layer20.

Here, the first surface S1of the semiconductor layer20may also be referred to as a “device formation surface” or a “main surface”, and the second surface S2side may be referred to as the “light incidence surface” or a “rear surface”. The solid-state image capturing device1A according to the first embodiment uses the photoelectric conversion region21(photoelectric conversion unit25) provided in the semiconductor layer20to photoelectrically convert light incident from the second surface (light incidence surface, rear surface) S2side of the semiconductor layer20.

“Plan view” refers to a view from a direction parallel to the thickness direction of the semiconductor layer20(the Z direction). “Cross-sectional view” refers to a cross-section parallel to the thickness direction of the semiconductor layer20(the Z direction) viewed from a direction orthogonal to the thickness direction of the semiconductor layer20(the Z direction) (that is, viewed from the X direction or the Y direction). The photoelectric conversion region21can also be referred to as a “photoelectric conversion cell”.

As illustrated inFIG.4, each photoelectric conversion region21of the plurality of photoelectric conversion regions (photoelectric conversion cells)21includes a p-type well region22provided in the semiconductor layer20, an n-type semiconductor region24provided in the p-type well region22, and the photoelectric conversion unit25described above. Although not illustrated inFIG.4, each photoelectric conversion region21includes the floating diffusion region FD and the transfer transistor TR described above, as well as the pixel transistors (AMP, SEL, and RST) included in the readout circuit15described above. Note also thatFIG.4illustrates a gate electrode31of the transfer transistor TR.

The floating diffusion region FD, the transfer transistor TR, and the pixel transistors (AMP, SEL, and RST) are provided on the first surface S1side of the semiconductor layer20.

As illustrated inFIG.4, the p-type well region22extends from the first surface S1side to the second surface S2side of the semiconductor layer20, and is constituted by a p-type semiconductor region, for example.

Here, the photoelectric conversion unit25is mainly constituted by the n-type semiconductor region24, and is configured as a pn junction photodiode (PD) by the p-type well region22and the n-type semiconductor region24.

As illustrated inFIG.4, the multilayer wiring layer30is disposed on the first surface S1side on the side of the semiconductor layer20opposite from the side on which the light incidence surface (the second surface S2) is located, and is configured such that a plurality of wiring layers each including wiring33are stacked with an interlayer insulating film32provided therebetween. The pixel transistors (AMP, SEL, and RST) and the transfer transistor TR of each pixel3are driven through the wiring33of the multilayer wiring layer30. Because the multilayer wiring layer30is disposed on the side opposite from the side of the semiconductor layer20on which the light incidence surface side (the second surface S2side) is located, the layout of the wiring33can be set with freedom.

The support substrate34is disposed on the side of the multilayer wiring layer30opposite from the side on which the semiconductor layer20is located. The support substrate34is a substrate for ensuring the strength of the semiconductor layer20in the manufacturing stage of the solid-state image capturing device1A. For example, a silicon (Si) substrate can be used as the material of the support substrate34.

As illustrated inFIG.4, the insulating layer35is provided between the semiconductor layer20and the optical filter layer40. The insulating layer35insulates and isolates the semiconductor layer20and the optical filter layer40. The insulating layer35covers the entirety of the light incidence surface side of the semiconductor layer20in the pixel array part2A such that the light incidence surface (second surface S2) side of the semiconductor layer20is a flat, even surface. A silicon oxide (SiO2) film can be used as the insulating layer35, for example.

As illustrated inFIG.4, the optical filter layer40includes: a first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; a first dielectric film42and a second dielectric film43, which are arranged in the thickness direction (the Z direction) of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; and a second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located. In other words, the optical filter layer40has a multilayer structure in which the first dielectric film42and the second dielectric film43, which have different refractive indices, are interposed between the two metal films (41and44).

In the first embodiment, the first dielectric film42is provided further on the first metal film41side than the second dielectric film43, and has a greater (higher) refractive index than the second dielectric film43.

Each of the first metal film41, the first dielectric film42, the second dielectric film43, and the second metal film44is provided across a plurality of pixels3. Although not limited thereto,FIG.4illustrates five pixels3(3c,3a,3b,3c, and3a) as an example, and the films are provided across the five pixels3. Furthermore, although not illustrated in detail, in the first embodiment, each of the first metal film41, the first dielectric film42, the second dielectric film43, and the second metal film44is provided across the entirety of the pixel array part2A, for example. Although not limited thereto, the first dielectric film42and the second dielectric film43are provided so as to be in contact with each other, for example.

As illustrated inFIGS.5and6, the first dielectric film42includes: a first part42awhich overlaps with a photoelectric conversion region21aof the pixel3ain plan view; a second part42bwhich overlaps with a photoelectric conversion region21bof the pixel3bin plan view and which is thicker than the first part42a; and a third part42cwhich overlaps with a photoelectric conversion region21cof the pixel3cin plan view and which is thicker than the second part42b. In other words, the thickness of the first dielectric film42is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness increases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.5and6, the second dielectric film43includes: a first part43awhich overlaps with the first part42aof the first dielectric film42in plan view; a second part43bwhich overlaps with the second part42bof the first dielectric film42in plan view and which is thinner than the first part43aof the second dielectric film43; and a third part43cwhich overlaps with the third part42cof the first dielectric film42in plan view and which is thinner than the second part43bof the second dielectric film43. In other words, the thickness of the second dielectric film43is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the first dielectric film42, the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.5and6, the optical filter layer40includes a first filter part40awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, a second filter part40bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and a third filter part40cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

The first filter part40aincludes the first parts42aand43aof the first and second dielectric films42and43, respectively, between the first metal film41and the second metal film44. The second filter part40bincludes the second parts42band43bof the first and second dielectric films42and43, respectively, between the first metal film41and the second metal film44. The third filter part40cincludes the third parts42cand43cof the first and second dielectric films42and43, respectively, between the first metal film41and the second metal film44.

The ratio of the thicknesses of the first dielectric film42and the second dielectric film43is different in each of the first filter part40a, the second filter part40b, and the third filter part40c. For example, although not limited thereto, the ratio of the thicknesses of the first dielectric film42and the second dielectric film43is 1:3 in the first filter part40a,2:2 in the second filter part40b, and 3:1 in the third filter part40c. A total thickness h1of the first dielectric film42and the second dielectric film43in the first filter part40a, a total thickness h2of the first dielectric film42and the second dielectric film43in the second filter part40b, and a total thickness h3of the first dielectric film42and the second dielectric film43in the third filter part40care designed to be the same. In other words, the total thickness of the first dielectric film42and the second dielectric film43is generally the same in the first filter part40a(h1), the second filter part40b(h2), and the third filter part40c(h3).

As illustrated inFIGS.5and6, a surface layer part42S on the second dielectric film43side of the first dielectric film42has a step part42z1produced by the difference in the thicknesses of the first part42aand the second part42bof the first dielectric film42, a step part42z2produced by the difference in the thicknesses of the second part42band the third part42cof the first dielectric film42, and a step part42z3produced by the difference in the thicknesses of the third part42cand the first part42aof the first dielectric film42.

In other words, the surface layer part42S of the first dielectric film42has step parts (42z1,42z2, and42z3) between the pixels3adjacent to each other.

On the other hand, a surface layer part43S on the second metal film44side of the second dielectric film43is flat across the pixels3adjacent to each other. In a manufacturing process (described later), the parts having different thicknesses (42a,42b, and42c) are formed by etching the surface layer part42S side of the first dielectric film42to form the step parts (42z1,42z2, and42z3) on the surface layer part42S side. The second dielectric film43covers the entirety of the first dielectric film42across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the first dielectric film42in the lower layer are embedded and the surface layer part43son the second metal film44side is a flat, even surface.

As described above, the first dielectric film42is provided further on the first metal film41side than the second dielectric film43, and the refractive index thereof greater than the refractive index of the second dielectric film43.

The first dielectric film42is constituted by an inorganic film containing any one material among titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (SiN), or hafnium oxide (HfO2), for example.

The second dielectric film43is also constituted by an inorganic film containing any one material among silicon oxide (SiO2) or silicon oxynitride (SiON), for example.

As illustrated inFIGS.5and6, each of the first metal film41and the second metal film44is provided across the pixels3adjacent to each other. Each of the first metal film41and the second metal film43is constituted by a film containing any one material among aluminum (Al), silver (Ag), gold (Au), copper (Cu), chromium (Cr), or tungsten (W), for example. The first metal film41is thicker than the second metal film44.

As illustrated inFIGS.5and6, the insulating layer45is provided on the side of the second metal film44opposite from the side on which the second dielectric film43is located. The insulating layer45is provided across the pixels3adjacent to each other and covers the second metal film44. The insulating layer45prevents incident light from being reflected at the second metal film44, and also protects the optical filter layer40. The insulating layer45is constituted by a silicon oxide film having excellent light transmittance, for example.

<<Method for Manufacturing Solid-State Image Capturing Device>>

A method for manufacturing the solid-state image capturing device1A according to the first embodiment will be described next with reference toFIGS.7A to7L. A case will be described where in the manufacturing method according to the first embodiment, the first dielectric film is formed before the second dielectric film.

First, as illustrated inFIG.7A, the semiconductor layer20is prepared. A monocrystalline silicon substrate is used as the semiconductor layer20, for example.

Next, as illustrated inFIG.7A, the p-type well region22, constituted by a p-type semiconductor region, is formed on the first surface S1side of the semiconductor layer20.

Next, as illustrated inFIG.7B, the plurality of photoelectric conversion regions21segmented by the isolation region23extending from the first surface S1side to the second surface S2side of the semiconductor layer20are formed in the semiconductor layer20, after which the n-type semiconductor region24is formed within the p-type well region22of each photoelectric conversion region21.

In this step, the photoelectric conversion unit25is formed as a pn junction photodiode (PD) by the p-type well region22and the n-type semiconductor region24.

Next, although not illustrated, the floating diffusion region FD, the transfer transistor TR, and the pixel transistors (AMP, SEL, and RST) included in the readout circuit15described above are formed on the first surface S1side of the semiconductor layer20.

Next, as illustrated inFIG.7C, the multilayer wiring layer30, in which a plurality of wiring layers each including the wiring33are stacked with the interlayer insulating film32provided therebetween, is formed on the first surface S1side of the semiconductor layer20.

Next, the support substrate34is joined to the side of the multilayer wiring layer30opposite from the side on which the semiconductor layer20is located. Then, as illustrated inFIG.7D, the second surface (light incidence surface) S2side of the semiconductor layer20is polished through CMP or the like until the isolation region23is exposed, which reduces the thickness of the semiconductor layer20.

Next, as illustrated inFIG.7E, the insulating layer (a planarization layer)35is formed on the second surface S2side of the semiconductor layer20. The insulating layer35can be formed by, for example, forming a silicon oxide film on the second surface S2side of the semiconductor layer20through CVD, and then polishing through CMP or etching back the surface of the silicon oxide film. The insulating layer35is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c), and covers the entire first surface S1side of the semiconductor layer20.

Next, as illustrated inFIG.7F, the first metal film41is formed on the side of the insulating layer35opposite from the side on which the semiconductor layer20is located. The first metal film41can be formed by forming a film containing any one of aluminum, silver (Ag), copper (Cu), gold (Au), chromium (Cr), or tungsten (W) through a well-known sputtering technique, atomic layer deposition (ALD), or the like, for example. The first metal film41is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

Next, as illustrated inFIG.7G, the first dielectric film42is formed on the side of the first metal film41opposite from the side on which the semiconductor layer20is located. The first dielectric film42can be formed by forming an inorganic film containing any one material of titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (SiN), or hafnium oxide (HfO2) through a well-known CVD technique, ALD, or the like, for example. The first dielectric film42is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

Next, using well-known photolithography and dry etching techniques, the first dielectric film42overlapping with the photoelectric conversion region21ain plan view is selectively etched to form the first part42a, which is thinner than the first dielectric film42overlapping with the photoelectric conversion regions21band21cin plan view, as illustrated inFIG.7H. In this step, a step part is formed by the difference in the thickness between the first part42aand the parts of the first dielectric film42aside from the first part.

Next, using well-known photolithography and dry etching techniques, the first dielectric film42overlapping with the photoelectric conversion region21bin plan view is selectively etched to form the second part42b, which is thinner than the first dielectric film42overlapping with the photoelectric conversion region21cand thicker than the first part42ain plan view, as illustrated inFIG.7I.

In this step, by forming the second part42b, the remaining first dielectric film42overlapping with the photoelectric conversion region21cin plan view becomes the third part42c, which is thicker than the second part42b.

The first dielectric film42having the first part42a, the second part42b, and the third part42c, which have different thicknesses, are formed in this step. The step part42z1produced by the difference in the thicknesses of the first part42aand the second part42b, the step part42z2produced by the difference in the thicknesses of the second part42band the third part42c, and the step part42z3produced by the difference in the thicknesses of the third part42cand the first part42aare also formed in the surface layer part42S of the first dielectric film42(seeFIGS.5and6).

Next, as illustrated inFIG.7J, the second dielectric film43, which has a refractive index different from that of the first dielectric film42, is formed on the side of the first dielectric film42opposite from the side on which the first metal film41is located. In the first embodiment, the second dielectric film43having a smaller (lower) refractive index than that of the first dielectric film42is formed. The second dielectric film43can be formed by forming, through CVD, an inorganic film containing any one material of silicon oxide (SiO2) or silicon oxynitride (SiON), for example, on the side of the first dielectric film42opposite from the side on which the first metal film41is located, and then polishing through CMP or etching back the surface of the film. The second dielectric film43is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the steps produced by the differences in the thickness of the first dielectric film42in the lower layer are embedded in the second dielectric film43, and the surface layer part43S is flattened.

Additionally, in this step, the second dielectric film43takes on a configuration including: the first part43awhich overlaps with the first part42aof the first dielectric film42in plan view; the second part43bwhich overlaps with the second part42bof the first dielectric film42in plan view and which is thinner than the first part43a; and the third part43cwhich overlaps with the third part42cof the first dielectric film42in plan view and which is thinner than the second part43b.

Additionally, in this step, the parts are formed such that the total thickness h1of the first parts42aand43aof the first and second dielectric films42and43, the total thickness h2of the second parts42band43bof the first and second dielectric films42and43, and the total thickness h3of the third parts42cand43cof the first and second dielectric films42and43are generally the same.

Next, as illustrated inFIG.7K, the second metal film44, which is thinner than the first metal film41, is formed on the side of the second dielectric film43opposite from the side on which the first dielectric film42is located. The second metal film44can be formed by forming a film containing any one of aluminum, silver (Ag), copper (Cu), gold (Au), chromium (Cr), or tungsten (W) through a well-known sputtering technique, ALD, or the like, for example. The second metal film44is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the step parts produced by the differences in the thickness of the first dielectric film42in the lower layer are embedded in the second dielectric film43, and the surface layer part43S of the second dielectric film43is flat across the photoelectric conversion regions21(pixels3) adjacent to each other, which makes it possible to increase the adhesion of the second metal film44and suppress peeling of the second metal film44.

The first filter part40a, which includes the first metal film41, the first parts42aand43aof the first and second dielectric films42and43, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21ain plan view, is formed in this step. The second filter part40b, which includes the first metal film41, the second parts42band43bof the first and second dielectric films42and43, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21bin plan view, is formed as well. The third filter part40c, which includes the first metal film41, the third parts42cand43cof the first and second dielectric films42and43, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21cin plan view, is formed as well. The optical filter layer40including the first filter part40a, the second filter part40b, and the third filter part40cis formed on the light incidence surface side (the second surface S2side) of the semiconductor layer20.

Next, as illustrated inFIG.7L, the insulating layer45covering the optical filter layer40is formed on the side of the optical filter layer40opposite from the side on which the semiconductor layer20is located.

The solid-state image capturing device1A including the semiconductor layer20, the multilayer wiring layer30, the support substrate34, the insulating layer35, the optical filter layer40, the insulating layer45, and the like is essentially completed by this step.

The solid-state image capturing device1A is formed in each of a plurality of chip formation regions separated by scribe lines (dicing lines) on a semiconductor substrate called a “semiconductor wafer”. The semiconductor chip2provided with the solid-state image capturing device1A illustrated inFIGS.1to4is formed by separating (fragmenting) the plurality of chip formation regions along the scribe lines individually.

<<Main Effects of First Embodiment>>

The main effects of the first embodiment will be described next.

As described with reference toFIGS.5and6, the optical filter layer40of the first embodiment can spectrally split the light incident from the second metal film44side (incident light) through reflection (resonance) and absorption between the first metal film41and the second metal film44. Furthermore, with the optical filter layer40of the first embodiment, changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43changes the optical path length, which makes it possible to change the wavelength band of the light passing through the filter parts (40a,40b, and40c). As a result, by employing a configuration in which the ratio of the thicknesses of the first dielectric film42and the second dielectric film43is different in the first filter part40a, the second filter part40b, and the third filter part40c, as in the optical filter layer40of the first embodiment, the wavelength bands of the light passing through the first filter part40a, the second filter part40b, and the third filter part40ccan be changed. Although the first embodiment describes changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43for the three filter parts40a,40b, and40cas an example, the ratio of the thicknesses of the first dielectric film42and the second dielectric film43can be changed so as to correspond to four or more filter parts, and the incident light can be spectrally split into light in a greater number of wavelength bands. Therefore, the solid-state image capturing device1A according to the first embodiment makes it possible to achieve spectral separation, where incident light is divided into a variety of wavelength bands.

Additionally, because the wavelength band of transmitted light can be changed by changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43, the optical filter layer40of the first embodiment can achieve spectral separation at a lower cost than a conventional color filter layer which uses a plurality of types of resins to which pigments are added.

Additionally, in the manufacturing process for the optical filter layer40of the first embodiment, the step parts produced by the differences in the thickness of the first dielectric film42in the lower layer are embedded in the second dielectric film43, and the surface layer part43S of the second dielectric film43is flat across the photoelectric conversion regions21(pixels3) adjacent to each other, which makes it possible to increase the adhesion of the second metal film44and suppress peeling of the second metal film44. Therefore, the solid-state image capturing device1A according to the first embodiment makes it possible to achieve spectral separation while suppressing a drop in yield caused by peeling of the second metal film44.

Additionally, in the optical filter layer40of the first embodiment, the first metal film41is thicker than the second metal film44, and thus color mixing can be reduced without changing the transmittance.

FIG.8Ais a characteristic chart indicating the quantum efficiency QE when the first metal film41and the second metal film44are the same thickness, andFIG.8Bis a characteristic chart indicating the quantum efficiency QE when the first metal film41is thicker than the second metal film44. In bothFIGS.8A and8B, D1to D6represent data obtained when the thickness of the first dielectric film42, which has the higher refractive index among the first and second dielectric films42and43, is changed sequentially.

As can be seen fromFIGS.8A and8B, setting the first metal film to be thicker than the second metal film results in a narrower spectrum half-value width, which makes it possible to reduce color mixing.

Second Embodiment

A second embodiment of the present technique will be described next with reference toFIGS.9to11.

FIG.9is a longitudinal cross-sectional view schematically illustrating the longitudinal cross-sectional structure of the pixel array part2A of a solid-state image capturing device1B, and illustrates five pixels3as an example.FIG.10is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.9, and illustrates pixels3aand3b, which are the second and third pixels of the five pixels3inFIG.9counted from the left side, as an example.FIG.11is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.9, and illustrates pixels3band3c, which are the third and fourth pixels of the five pixels3inFIG.9counted from the left side, as an example.

The solid-state image capturing device1B according to the second embodiment of the present technique has basically the same configuration as the solid-state image capturing device1A according to the first embodiment described above, with the exception of the following configurations.

First, as illustrated inFIG.9, the solid-state image capturing device1B according to the second embodiment includes an optical filter layer46instead of the optical filter layer40illustrated inFIG.4described above in the first embodiment. The optical filter layer46has basically the same configuration as the optical filter layer40, but the order of arrangement of the first dielectric film42and the second dielectric film43in the thickness direction of the semiconductor layer20is different.

Specifically, in the optical filter layer40of the first embodiment described above, the first dielectric film42is provided further on the first metal film41side than the second dielectric film43, as illustrated inFIG.4.

In contrast, in the optical filter layer46of the second embodiment, the first dielectric film42is provided further on the second metal film44side than the second dielectric film43, as illustrated inFIG.9. The refractive index of the first dielectric film42is greater than the refractive index of the second dielectric film43.

In other words, the optical filter layer46of the second embodiment has a multilayer structure in which the first metal film41, the second dielectric film43, the first dielectric film42, and the second metal film44are stacked in that order from the second surface S2side of the semiconductor layer20.

Additionally, as illustrated inFIGS.10and11, the first part42a, the second part42b, and the third part42cof the first dielectric film42are provided further on the second metal film44side than the first part43a, the second part43b, and the third part43cof the second dielectric film43, in the first filter part40a, the second filter part40b, and the third filter part40bof the optical filter layer46as well.

Furthermore, as illustrated inFIGS.10and11, in the optical filter layer46of the second embodiment, the surface layer part43S on the first dielectric film42side of the second dielectric film43has a step part43z1produced by the difference in the thicknesses of the first part43aand the second part43bof the second dielectric film43, a step part43z2produced by the difference in the thicknesses of the second part43band the third part43cof the second dielectric film43, and a step part43z3produced by the difference in the thicknesses of the third part43cand the first part43aof the second dielectric film43. The surface layer part43S of the second dielectric film43has the step parts (43z1,43z2, and43z3) between the pixels3adjacent to each other.

On the other hand, as illustrated inFIGS.10and11, the surface layer part43S on the second metal film44side of the second dielectric film43is flat across the pixels3adjacent to each other. Because the first dielectric film42is formed after the second dielectric film43in the manufacturing process, the steps produced by the differences in the thickness of the first dielectric film42in the lower layer are embedded in the second dielectric film43, and a surface layer part44son the second metal film44side becomes a flat, even surface, covering the entirety of the first dielectric film42across the pixels3adjacent to each other.

Additionally, in the optical filter layer46of the second embodiment, the ratio of the thicknesses of the first dielectric film42and the second dielectric film43is different in the first filter part40a, the second filter part40b, and the third filter part40c. Furthermore, the total thickness of the first dielectric film42and the second dielectric film43is generally the same in the first filter part40a(h1), the second filter part40b(h2), and the third filter part40c(h3).

The solid-state image capturing device1B according to the second embodiment provides effects similar to those of the solid-state image capturing device1A according to the first embodiment described above.

Although the foregoing first and second embodiments describe a case where two dielectric films42and43are provided, three or more dielectric films may be provided. In addition, a third dielectric film may be provided between the first dielectric film42and the second dielectric film43. In this case, it is preferable to use a film having a greater refractive index than the second dielectric film43as the third dielectric film.

Third Embodiment

In a third embodiment, an optical filter layer50C including a light absorption film47will be described as the optical filter layer.

FIG.12is a longitudinal cross-sectional view schematically illustrating the longitudinal cross-sectional structure of the pixel array part2A of a solid-state image capturing device1C, and illustrates five pixels3as an example.

FIG.13is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.12, and illustrates pixels3aand3b, which are the second and third pixels of the five pixels3inFIG.12counted from the left side, as an example.

FIG.14is a longitudinal cross-sectional view illustrating two pixels3adjacent to each other inFIG.12, and illustrates pixels3band3c, which are the third and fourth pixels of the five pixels3inFIG.12counted from the left side, as an example.

The solid-state image capturing device1C according to the third embodiment of the present technique has basically the same configuration as the solid-state image capturing device1A according to the first embodiment described above, with the exception of the following configurations.

First, as illustrated inFIG.12, the solid-state image capturing device1C according to the third embodiment includes the optical filter layer50C instead of the optical filter layer40illustrated inFIG.4described above in the first embodiment. The other configurations are generally the same as those described in the foregoing first embodiment.

As illustrated inFIG.12, the optical filter layer50C of the third embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film42and the second dielectric film43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43. The optical filter layer50C of the third embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and two second dielectric films43-1and43-2as the second dielectric film43. The two first dielectric films42-1and42-2have a higher (greater) refractive index than the respective two second dielectric films43-1and43-2. The light absorption film47has a higher (greater) light absorption rate than the two first dielectric films42-1and42-2and the two second dielectric films43-1and43-2.

Here, the first dielectric film42may be referred to as a high refraction film, and the second dielectric film43may be referred to as a low refraction film.

Each of the first dielectric film (high refraction film)42-1and the second dielectric film (low refraction film)43-1is provided further on the first metal film41side than the light absorption film47. Furthermore, the first dielectric film42-1is provided further on the light absorption film47side than the second dielectric film43-1. Likewise, each of the first dielectric film (high refraction film)42-2and the second dielectric film (low refraction film)43-2is provided further on the second metal film44side than the light absorption film47. Furthermore, the first dielectric film42-2is provided further on the light absorption film47side than the second dielectric film43-2. In other words, the optical filter50C of the third embodiment includes a resonance layer52C in which the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer52C is provided between the first metal film41and the second metal film44.

As illustrated inFIG.12, each of the first metal film41, the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44is provided across a plurality of pixels3. Although not limited thereto,FIG.12illustrates five pixels3(3c,3a,3b,3c, and3a) as an example, and the films are provided across the five pixels3. Furthermore, although not illustrated in detail, in the third embodiment, each of the first metal film41, the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44is provided across the entirety of the pixel array part2A, for example.

Although not limited thereto, of the first metal film41, the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44, the pairs of films facing each other in the thickness direction are provided so as to be in contact with each other, for example.

<Second Dielectric Film on First Metal Film Side>

As illustrated inFIGS.13and14, the second dielectric film43-1located further on the first metal film41side than the light absorption film47includes a first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view (seeFIG.13), a second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view and which is thinner than the first part43-1a(seeFIGS.13and14), and a third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view and which is thinner than the second part43-1b(seeFIG.14). In other words, the thickness of the second dielectric film43-1is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness decreases in stages in order of the pixels3a,3b, and3c.

<First Dielectric Film on First Metal Film Side>

As illustrated inFIGS.12and13, the first dielectric film42-1further on the first metal film41side than the light absorption film47includes a first part42-1awhich overlaps with the first part43-1aof the second dielectric film43-1in plan view (seeFIG.13), a second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1in plan view and which is thicker than the first part42-1aof the first dielectric film42-1(seeFIGS.13and14), and a third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1in plan view and which is thicker than the second part43-1bof the second dielectric film43-1(seeFIG.14). In other words, the thickness of the first dielectric film42-1is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the second dielectric film43-1, the thickness increases in stages in order of the pixels3a,3b, and3c.

<First Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.13and14, the first dielectric film42-2located further on the second metal film44side than the light absorption film47includes a first part42-2awhich overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21aof the pixel3a) in plan view (seeFIG.13), a second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view and which is thicker than the first part42-2a(seeFIGS.13and14), and a third part42-2cwhich overlaps with the first part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view and which is thicker than the second part42-2b(seeFIG.14). In other words, the thickness of the first dielectric film42-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness increases in stages in order of the pixels3a,3b, and3c.

<Second Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.13and14, the second dielectric film43-2located further on the second metal film44side than the light absorption film47includes a first part43-2awhich overlaps with the first part42-2aof the first dielectric film42-2in plan view (seeFIG.13), a second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view and which is thinner than the first part43-2aof the second dielectric film43-2(seeFIGS.13and14), and a third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view and which is thinner than the second part43-2bof the second dielectric film43-2(seeFIG.14). In other words, the thickness of the second dielectric film43-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the first dielectric film42-2, the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.13and14, the light absorption film47is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c. Here, the thickness being the same includes a permissible range of variation occurring during the manufacturing process.

As illustrated inFIGS.13and14, the optical filter layer50C includes a first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, a second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and a third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.13, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the first part42-1aof the first dielectric film42-1, the light absorption film47, the first part42-2aof the first dielectric film42-2, and the first part43-2aof the second dielectric film43-2, provided in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.13and14, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the second part42-1bof the first dielectric film42-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, provided in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.14, the third filter part51cincludes the third part43-1cof the second dielectric film43-1, the third part42-1cof the first dielectric film42-1, the light absorption film47, the third part42-2cof the first dielectric film42-2, and the third part43-2cof the second dielectric film43-2, provided in that order from the first metal film41side, between the first metal film41and the second metal film44.

In other words, the first dielectric42and the second dielectric film43are provided on the first metal film41side and the second metal film44side, respectively, of the light absorption film47, in each of the first to third filter parts51ato50c.

As illustrated inFIGS.13and14, each of the first filter part51a, the second filter part51b, and the third filter part51chas a different ratio of the thicknesses of the first dielectric film42-1and the second dielectric film43-1on the first metal film41side of the light absorption film47. Additionally, each of the first filter part51a, the second filter part51b, and the third filter part51chas a different ratio of the thicknesses of the first dielectric film42-2and the second dielectric film43-2on the second metal film44side of the light absorption film47. In other words, the ratio of the thicknesses of the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43is different in each of the first filter part51a, the second filter part51b, and the third filter part51c.

For example, although not limited thereto, on the first metal film41side of the light absorption film47, the ratio of the thicknesses of the first dielectric film42-1and the second dielectric film43-1is 1:3 in the first filter part51a,2:2 in the second filter part51b, and 3:1 in the third filter part51c. A total thickness h1aof the first dielectric film42-1and the second dielectric film43-1in the first filter part51a, a total thickness h1bof the first dielectric film42-1and the second dielectric film43-1in the second filter part51b, and a total thickness h1cof the first dielectric film42-1and the second dielectric film43-1in the third filter part51care designed to be the same. In other words, the total thickness of the first dielectric film42-1and the second dielectric film43-1is generally the same in the first filter part51a(h1a), the second filter part51b(h1b), and the third filter part51c(h1c).

Additionally, although not limited thereto, on the second metal film44side of the light absorption film47, the ratio of the thicknesses of the first dielectric film42-2and the second dielectric film43-2is 1:3 in the first filter part51a,2:2 in the second filter part51b, and 3:1 in the third filter part51c. A total thickness h2aof the first dielectric film42-2and the second dielectric film43-2in the first filter part51a, a total thickness h2bof the first dielectric film42-2and the second dielectric film43-2in the second filter part51b, and a total thickness h2cof the first dielectric film42-2and the second dielectric film43-2in the third filter part51care designed to be the same. In other words, the total thickness of the first dielectric film42-2and the second dielectric film43-2is generally the same in the first filter part51a(h2a), the second filter part51b(h2b), and the third filter part51c(h2c).

In other words, in the optical filter layer50C of the fifth embodiment, the thickness of the resonance layer52C between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface on First Metal Side>

As illustrated inFIGS.13and14, on the first metal41side of the light absorption film47, a surface layer part43-1S on the first dielectric film42-1side of the second dielectric film43-1has a step part43-1z1produced by the thickness difference (the difference in the thicknesses) of the first part43-1aand the second part43-1bof the second dielectric film43-1, a step part43-1z2produced by the difference in the thicknesses of the second part43-1band the third part43-1cof the second dielectric film43-1, and a step part43-1z3produced by the difference in the thicknesses of the third part43-1cand the first part43-1aof the second dielectric film43-1. In other words, the surface layer part43-1S of the second dielectric film43has step parts (43-1z1,43-1z2, and43-1z3) between the pixels3adjacent to each other.

On the other hand, a surface layer part42-1S on the light absorption film47side of the first dielectric film42-1is flat across the pixels3adjacent to each other. In the manufacturing process (described later), the surface layer part43-1S side of the second dielectric film43-1is etched to form parts having different thicknesses (the first part43-1a, the second part43-1b, and the third part43-1c), and thus the step parts (43-1z1,43-1z2, and43-1z3) are formed on the surface layer part43-1S side. The first dielectric film42-1covers the entirety of the second dielectric film43-1across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the second dielectric film43-1in the lower layer are embedded and the surface layer part42-1S on the light absorption film47side is a flat, even surface.

<Steps and Flat Surface on Second Metal Film Side>

As illustrated inFIGS.13and14, on the second metal film44side of the light absorption film47, a surface layer part42-2S on the second dielectric film43-2side of the first dielectric film42-2has a step part42-2z1produced by the difference in the thicknesses of the first part42-2aand the second part42-2bof the first dielectric film42-2, a step part42-2z2produced by the difference in the thicknesses of the second part42-2band the third part42-2cof the first dielectric film42-1, and a step part42-z3produced by the difference in the thicknesses of the third part42-2cand the first part42-2aof the first dielectric film42-2.

In other words, the surface layer part42-2S of the first dielectric film42-2has step parts (42-2z1,42-2z2, and42-2z3) between the pixels3adjacent to each other.

On the other hand, a surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3adjacent to each other. In the manufacturing process (described later), the surface layer part42-2S side of the first dielectric film42-2is etched to form parts having different thicknesses (the first part42-2a, the second part42-2b, and the third part42-2c), and thus the step parts (42-2z1,42-2z2, and42-2z3) are formed on the surface layer part42-2S side. The second dielectric film43-2covers the entirety of the first dielectric film42-2across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded and the surface layer part43-2son the second metal film44side is a flat, even surface.

As illustrated inFIGS.13and14, each of the first dielectric films42-1and42-2is provided further on the light absorption film47side than the second dielectric films43-1and43-2, respectively, and has a higher (greater) refractive index than the refractive index of each of the second dielectric films43-1and43-2, respectively.

An inorganic film containing any one material among titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (SiN), or hafnium oxide (HfO2), for example, can be used for each of the first dielectric films42-1and42-2. The first dielectric films42-1and42-2may be constituted by the same material, or may be constituted by different materials.

An inorganic film containing any one material among silicon oxide (SiO2) or silicon oxynitride (SiON), for example, can be used for each of the second dielectric films43-1and43-2. The second dielectric films43-1and43-2may be constituted by the same material, or may be constituted by different materials.

As illustrated inFIGS.13and14, the light absorption film47is provided across the pixels3(photoelectric conversion regions21) adjacent to each other. A film containing a semiconductor material such as amorphous silicon (a-Si), monocrystalline silicon (mono-Si), polysilicon (Poly-Si), germanium (Ge), silicon germanium (Si—Ge), indium-gallium-arsenic (InGaAs), or the like, a film containing a metal material such as titanium (Ti), tungsten (W), copper (Cu), or the like, or an alloy material having these metal materials as principal components, can be used as the light absorption film47, for example.

<First and Second Metal Films>

As illustrated inFIGS.13and14, each of the first metal film41and the second metal film44is provided across the pixels3(photoelectric conversion regions21) adjacent to each other, as in the first embodiment described above. Furthermore, the first metal film41is thicker than the second metal film44. A film containing any one material among aluminum (Al), silver (Ag), gold (Au), copper (Cu), chromium (Cr), or tungsten (W), for example, can be used as each of the first metal film41and the second metal film44.

<<Method for Manufacturing Solid-State Image Capturing Device>>

A method for manufacturing the solid-state image capturing device1C according to the third embodiment will be described next with reference toFIGS.15A to15I.

The manufacturing method of the third embodiment is similar to the foregoing first embodiment up to the step of forming the first metal film41, the steps up to the forming of the first metal film41will not be described.

After the first metal film41is formed as illustrated inFIG.15A, the second dielectric film43-1is formed on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, as illustrated inFIG.15B. The second dielectric film43-1can be formed by depositing an inorganic film containing any material among silicon oxide (SiO2) or silicon oxynitride (SiON), for example, through CVD. The second dielectric film43-1is formed across the photoelectric conversion regions21adjacent to each other in plan view (21a,21b, and21c).

Next, using well-known photolithography and dry etching techniques, the second dielectric film43-1is selectively etched to form the first part43-1a, which overlaps with the photoelectric conversion region21ain plan view, the second part43-1b, which overlaps with the photoelectric conversion region21bin plan view and which is thinner than the first part43-1a, and the third part43-1c, which overlaps with the photoelectric conversion region21cin plan view and which is thinner than the second part43-1b, as illustrated inFIG.15C. Each of the first part43-1a, the second part43-1b, and the third part43-1ccan be formed by repeating the photolithography and the dry etching steps several times.

In this step, the step part43-1z1produced by the difference in the thicknesses of the first part43-1aand the second part43-1b, the step part43-1z2produced by the difference in the thicknesses of the second part43-1band the third part43-1c, and the step part43-1z3produced by the difference in the thicknesses of the third part43-1cand the first part43-1aare formed in the surface layer part43-1S on the side of the second dielectric film43-1opposite from the side on which the first metal film41is located.

Next, as illustrated inFIG.15D, the first dielectric film42-1having a refractive index different from that of the second dielectric film43-1is formed on the surface part43-1S side of the second dielectric film43-1. In the first embodiment, the first dielectric film42-1having a higher (greater) refractive index than the second dielectric film43-1is formed. The first dielectric film42-1can be formed by forming an inorganic film containing any one material of titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (SiN), or hafnium oxide (HfO2), for example, on the surface layer part43-1S side of the second dielectric film43-1through a well-known CVD technique, ALD, or the like, and then flattening the surface of the film through CMP or etching the film back. The first dielectric film42-1is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the steps produced by the differences in the thickness of the second dielectric film43-1in the lower layer are embedded in the first dielectric film42-1, and the surface layer part42-1S is flattened.

Additionally, in this step, the first dielectric film42-1takes on a configuration including the first part42-1awhich overlaps with the first part43-1aof the second dielectric film43-1in plan view, the second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1in plan view and which is thicker than the first part42-1a, and the third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1in plan view and which is thicker than the second part42-1b.

Additionally, in this step, the parts are formed such that the total thickness h1aof the first parts43-1aand42-1aof the second and first dielectric films43-1and42-1, the total thickness h1bof the second parts43-1band42-1bof the second and first dielectric films43-1and42-1, and the total thickness h1cof the third parts43-1cand42-1cof the first and second dielectric films43-1and42-1are generally the same.

Next, as illustrated inFIG.15E, the light absorption film47and the first dielectric film42-2are formed in that order on the side of the first dielectric film42-1opposite from the side on which the first metal film41is located.

The light absorption film47can be formed by depositing a film containing a semiconductor material such as amorphous silicon (a-Si), monocrystalline silicon (mono-Si), polysilicon (Poly-Si), germanium (Ge), silicon germanium (Si—Ge), indium-gallium-arsenic (InGaAs), or the like, a film containing a metal material such as titanium (Ti), tungsten (W), copper (Cu), or the like, or an alloy material having these metal materials as principal components, for example. The light absorption film47is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

The first dielectric film42-2can be formed by forming an inorganic film containing any one material of titanium oxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (SiN), or hafnium oxide (HfO2) through a well-known CVD technique, ALD, or the like, for example. The first dielectric film42-2is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the step parts produced by the differences in the thickness of the second dielectric film43-1in the lower layer are embedded in the first dielectric film42-1, and the surface layer part42-1S of the first dielectric film42-1is flat across the photoelectric conversion regions21adjacent to each other, which makes it possible to increase the adhesion of each of the light absorption film47and the first dielectric film42-2, and suppress peeling of each of the light absorption film47and the first dielectric film42-2.

Next, using well-known photolithography and dry etching techniques, the first dielectric film42-2is selectively etched to form the first part42-2a, which overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21a) in plan view, the second part42-2b, which overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21b) in plan view and which is thicker than the first part42-2a, and the third part42-2c, which overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21c) in plan view and which is thicker than the second part42-2b, as illustrated inFIG.15F. Each of the first part42-2a, the second part42-2b, and the third part42-2ccan be formed by repeating the photolithography and the dry etching steps several times.

In this step, the step part42-2z1produced by the difference in the thicknesses of the first part42-2aand the second part42-2b, the step part42-2z2produced by the difference in the thicknesses of the second part42-2band the third part42-2c, and the step part42-2z3produced by the difference in the thicknesses of the third part42-2cand the first part42-2a, are formed in the surface layer part42-2S on the side of the first dielectric film42-2opposite from the side on which the light absorption film47is located.

Next, as illustrated inFIG.15G, the second dielectric film43-2, which has a refractive index different from that of the first dielectric film42-2, is formed on the side of the first dielectric film42-2opposite from the side on which the light absorption film47(the first metal film41) is located. In the third embodiment, the second dielectric film43-2having a lower (smaller) refractive index than that of the first dielectric film42-2is formed. The second dielectric film43-2can be formed by forming, through CVD, an inorganic film containing any one material of silicon oxide (SiO2) or silicon oxynitride (SiON), for example, on the side of the first dielectric film42-2opposite from the side on which the light absorption film47is located, and then polishing through CMP or etching back the surface of the film. The second dielectric film43-2is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the steps produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded in the second dielectric film43-2, and the surface layer part43-2S is flattened.

Additionally, in this step, the second dielectric film43-2takes on a configuration including: the first part43-2awhich overlaps with the first part42-2aof the first dielectric film42-2in plan view; the second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view and which is thinner than the first part43-2a; and the third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view and which is thinner than the second part43-2b.

Additionally, in this step, the parts are formed such that the total thickness h2aof the first parts42-2aand43-2aof the first and second dielectric films42-2and43-2, the total thickness h2bof the second parts42-2band43-2bof the first and second dielectric films42-2and43-2, and the total thickness h2cof the third parts42-2cand43-2cof the first and second dielectric films42-2and43-2are generally the same.

Additionally, the resonance layer52C, which includes the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2, is formed in this step.

Next, as illustrated inFIG.15H, the second metal film44, which is thinner than the first metal film41, is formed on the side of the second dielectric film43-2opposite from the side on which the light absorption film47(the first dielectric film42-2) is located. The second metal film44can be formed by forming a film containing any one of aluminum, silver (Ag), copper (Cu), gold (Au), chromium (Cr), or tungsten (W) through a well-known sputtering technique, ALD, or the like, for example. The second metal film44is formed across the photoelectric conversion regions21adjacent to each other (21a,21b, and21c).

In this step, the step parts produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded in the second dielectric film43-2, and the surface layer part43-2S of the second dielectric film43-2is flat across the photoelectric conversion regions21(pixels3) adjacent to each other, which makes it possible to increase the adhesion of the second metal film44and suppress peeling of the second metal film44.

The first filter part51a, which includes the first metal film41, the first parts42-1a,42-2a,43-1a, and43-2aof the first and second dielectric films42-1,42-2,43-1, and43-2, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21ain plan view, is formed in this step.

Additionally, the first filter part51b, which includes the first metal film41, the second parts42-1b,42-2b,43-1b, and43-2bof the first and second dielectric films42-1,42-2,43-1, and43-2, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21bin plan view, is formed in this step.

Additionally, the first filter part51c, which includes the first metal film41, the third parts42-1c,42-2c,43-1c, and43-2cof the first and second dielectric films42-1,42-2,43-1, and43-2, respectively, and the second metal film44, and which overlaps with the photoelectric conversion region21cin plan view, is formed in this step.

The optical filter layer50C including the first filter part51a, the second filter part51b, and the third filter part51cis formed on the light incidence surface side (the second surface S2side) of the semiconductor layer20.

Next, as illustrated inFIG.15I, the insulating layer45covering the optical filter layer50C (the second metal film44) is formed on the side of the optical filter layer50C opposite from the side on which the semiconductor layer20is located.

The solid-state image capturing device1C including the semiconductor layer20, the multilayer wiring layer30, the support substrate34, the insulating layer35, the optical filter layer50C, the insulating layer45, and the like is essentially completed by this step.

Note that the solid-state image capturing device1C takes on the state of the semiconductor chip2illustrated inFIG.1by dividing a semiconductor wafer including the semiconductor layer20, the optical filter layer50C, and the like into chip formation regions.

<<Light Absorption Function of Optical Filter Layer>>

A light absorption function of the optical filter layer50C according to the third embodiment will be described next with comparison to the optical filter layer40according to the foregoing first embodiment serving as a reference example.

In an optical filter layer using Fabry-Perot resonance, a sub-peak may appear on the short wavelength side when the signal is taken on the long wavelength side. Such a sub-peak may affect color mixing, and it is therefore preferable to suppress the sub-peak.

FIG.16Ais a longitudinal cross-sectional view schematically illustrating the optical filter layer40of the first embodiment as a reference example.

FIG.16Bis a diagram illustrating a correlation between transmittance and the thickness of the first dielectric film (high refraction film)42in the optical filter layer40of the reference example illustrated inFIG.16A(a diagram illustrating the dependence of transmittance on the thickness of the first dielectric film).

FIG.17Ais a longitudinal cross-sectional view schematically illustrating the optical filter layer50C of the third embodiment.

FIG.17Bis a diagram illustrating a correlation between transmittance and the total thickness of two first dielectric films (high refraction films)42on respective sides of the light absorption film47in the optical filter layer50C of the third embodiment illustrated inFIG.17A(a diagram illustrating the dependence of transmittance on the thickness of the first dielectric film).

A difference between the optical filter layer40of the reference example illustrated inFIG.16Aand the optical filter layer50C of the third embodiment illustrated inFIG.17Ais the presence or absence of the light absorption film47. Furthermore, in the optical filter layer50C of the third embodiment, the first dielectric film42and the second dielectric film43are each provided on both sides of the light absorption film47in the thickness direction.

InFIGS.16B and17B, “T” represents the thickness of the first dielectric film (high refraction film)42. The data inFIG.16Bis data obtained when, for example, the thickness of a resonance layer52A between the first metal film41and the second metal film44is 120 nm, the thickness of the first metal film41is 10 nm, the thickness of the second metal film44is 5 nm, and TiO2film is used as the first dielectric film42, in the optical filter layer40of the reference example illustrated inFIG.16A.

Meanwhile, the data inFIG.17Bis data obtained when, for example, the thickness of the resonance layer52C between the first metal film41and the second metal film44is 270 nm, the thickness of the light absorption film47is 10 nm, the thickness of the first metal film41is 10 nm, the thickness of the second metal film44is 5 nm, TiO2film is used as the first dielectric film42, and Ge film is used as the light absorption film47, in the optical filter layer50C of the third embodiment illustrated inFIG.17A.

As illustrated inFIG.16B, in the optical filter layer40of the reference example, at T=120 nm, secondary resonance (sub-peak) occurs on the short wavelength side separately from the primary resonance.

In contrast, as illustrated inFIG.17B, in the optical filter layer50C of the third embodiment, the secondary resonance (sub-peak) on the short wavelength side can be eliminated by the light absorption film47.

FIG.18is a diagram illustrating stationary waves (standing waves) for each of orders of resonance in a Fabry-Perot resonance structure in which a dielectric film is interposed between two metal films. In the figure, a region R1enclosed within the solid line corresponds to the optical filter layer40of the reference example illustrated inFIG.16A.

FIG.19is a diagram illustrating stationary waves (standing waves) for each of orders of resonance in a Fabry-Perot resonance structure in which a dielectric film, into which a light absorption film has been inserted, is interposed between two metal films. In the figure, a region R2enclosed within the solid line corresponds to the optical filter layer50C of the third embodiment illustrated inFIG.17A. A Ge film is used as the light absorption film.

The stationary waves Sw indicated inFIG.18have high light intensities at the antinodes, and low light intensities at the nodes.

Accordingly, as illustrated inFIG.19, inserting the light absorption film47at the antinode parts of the stationary wave Sw makes it possible to selectively absorb stationary waves Sw at odd-numbered orders (m=1 and 3) and suppress resonance at odd-numbered orders (m=1 and 3).

FIG.20is a diagram illustrating a correlation between transmittance, the thickness of the resonance layer52A in the optical filter layer40according to the reference example illustrated inFIG.16A, and the thickness of the resonance layer52C in the optical filter layer50C according to the third embodiment illustrated inFIG.17A.

InFIG.20, data D11is data obtained when, for example, the thickness of the resonance layer52A is 120 nm, the thickness of the first dielectric film42is 110 nm, and TiO2film is used as the first dielectric film42, in the optical filter layer40of the reference example illustrated inFIG.16A. Meanwhile, data D12is data obtained when, for example, the thickness of the resonance layer52C is 270 nm, the thickness of the light absorption film47is 10 nm, the total thickness of the two first dielectric films42is 200 nm, and TiO2film is used as the first dielectric film42, in the optical filter layer50C of the third embodiment illustrated inFIG.17A.

As illustrated inFIG.20, making the resonance layer52C thicker than the resonance layer52A makes it possible to use the peak at m=2 as a main peak, i.e., a higher-order peak with a small half-value width, which makes it possible to improve the accuracy of light source estimation.

FIG.21Ais a diagram illustrating stationary waves (standing waves) for each of orders of resonance in a Fabry-Perot resonance structure in which a dielectric film, into which a light absorption film has been inserted, is interposed between two metal films. In the figure, a region R3enclosed within the solid line corresponds to the optical filter layer50C of the third embodiment illustrated inFIG.17A. A Ge film is used as the light absorption film.FIG.21Bis a diagram illustrating correlation between transmittance and the thickness of the light absorption film in the Fabry-Perot resonance structure illustrated inFIG.21A(a diagram illustrating the dependence of transmittance on the thickness of the light absorption film). As can be seen fromFIGS.21A and21B, setting the thickness of the light absorption film47to at least 30 nm makes it possible to suppress a peak at m=4 as well. In the optical filter layer50C of the third embodiment, the thickness of the light absorption film47is preferably at least 10% of the thickness of the resonance layer52C.

FIG.22is a diagram illustrating a correlation between transmittance and the thickness of a light absorption film in a Fabry-Perot resonance structure in which a dielectric film, into which the light absorption film47has been inserted, is interposed between two metal films (a diagram illustrating the dependence of the transmittance on the thickness of the light absorption film). A Ge film is used as the light absorption film47.

FromFIG.22, it can be seen that the light absorption film47has an effect of suppressing sub-peaks from a thickness of at least 2 nm.

FIG.23is a diagram illustrating a correlation between transmittance and the material of a light absorption film in a Fabry-Perot resonance structure in which a dielectric film, into which the light absorption film47has been inserted, is interposed between two metal films (a diagram illustrating the dependence of the transmittance on the material of the light absorption film). FromFIG.23, it can be seen that the light absorption film47has an effect of suppressing sub-peaks when formed from a material having an extinction coefficient which is not 0.

<<Main Effects of Third Embodiment>

The optical filter layer50C of the third embodiment has a Fabry-Perot resonance structure. As described with reference toFIGS.13and14, the optical filter layer50C of the third embodiment can spectrally split the light incident from the second metal film44side (incident light) through reflection (resonance) and absorption between the first metal film41and the second metal film44. Furthermore, with the optical filter layer50C of the third embodiment, changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43changes the optical path length, which makes it possible to change the wavelength band of the light passing through the filter parts (51a,51b, and51c). As a result, by employing a configuration in which the ratio of the thicknesses of the first dielectric film42and the second dielectric film43is different in the first filter part51a, the second filter part51b, and the third filter part51c, as in the optical filter layer50C of the third embodiment, the wavelength bands of the light passing through the first filter part51a, the second filter part51b, and the third filter part51ccan be changed. Although the third embodiment describes changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43for the three filter parts51a,51b, and51cas an example, the ratio of the thicknesses of the first dielectric film42and the second dielectric film43can be changed so as to correspond to four or more filter parts, and the incident light can be spectrally split into light in a greater number of wavelength bands. Therefore, like the solid-state image capturing device1A of the first embodiment described above, the solid-state image capturing device1C according to the third embodiment makes it possible to achieve spectral separation, where incident light is divided into a variety of wavelength bands.

Additionally, like the foregoing first embodiment, because the wavelength band of transmitted light can be changed by changing the ratio of the thicknesses of the first dielectric film42and the second dielectric film43, the optical filter layer50C of the third embodiment can achieve spectral separation at a lower cost than a conventional color filter layer which uses a plurality of types of resins to which pigments are added.

Additionally, in the manufacturing process for the optical filter layer50C of the third embodiment, the step parts produced by the differences in the thickness of the dielectric film in the lower layer are embedded in the dielectric film in the upper layer, and the surface layer part of the dielectric film in the upper layer is flat across the photoelectric conversion regions21(pixels3) adjacent to each other, which makes it possible to increase the adhesion of the second metal film44and suppress peeling of the second metal film44. Therefore, like the solid-state image capturing device1A according to the first embodiment described above, the solid-state image capturing device1C according to the third embodiment makes it possible to achieve spectral separation while suppressing a drop in yield caused by peeling of the second metal film44.

Additionally, like the optical filter layer40of the first embodiment described above, in the optical filter layer50C of the third embodiment, the first metal film41is thicker than the second metal film44, and thus color mixing can be reduced without changing the transmittance.

Additionally, the optical filter layer50C of the third embodiment includes the light absorption film47provided between the first dielectric film42and the second dielectric film43, and thus sub-peaks on the short wavelength side can be eliminated. Therefore, the solid-state image capturing device1C according to the third embodiment makes it possible to further suppress color mixing, which makes it possible to greatly improve the estimation accuracy of the light source.

In addition, the solid-state image capturing device1C according to the third embodiment makes it possible to use a higher-order peak, which in turn makes it possible to reduce the half-value width and improve the estimation accuracy of the light source.

Fourth Embodiment

A solid-state image capturing device1D according to a fourth embodiment of the present technique, illustrated inFIGS.24to26, has basically the same configuration as in the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.24to26, the solid-state image capturing device1D according to the fourth embodiment of the present technique includes an optical filter layer50D instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. The difference between the optical filter layer50D of the fourth embodiment and the optical filter layer50C of the third embodiment described above is that the optical filter layer50D does not include the first dielectric film42-1.

As illustrated inFIG.24, the optical filter layer50D of the fourth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50D of the fourth embodiment further includes one first dielectric film42-2as the first dielectric film42, and two second dielectric films43-1and43-2as the second dielectric film43. In other words, the optical filter layer50D of the fourth embodiment includes a resonance layer47D in which the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer47D is provided between the first metal film41and the second metal film44.

As illustrated inFIG.24, each of the first metal film41, the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44is provided across a plurality of pixels3. As in the third embodiment described above,FIG.24illustrates five pixels3(3c,3a,3b,3c, and3a) as an example, and the films are provided across the five pixels3. Furthermore, although not illustrated in detail, in the fourth embodiment as well, each of the first metal film41, the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44is provided across the entirety of the pixel array part2A, for example.

Although not limited thereto, of the first metal film41, the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, the second dielectric film43-2, and the second metal film44, the pairs of films facing each other in the thickness direction are provided so as to be in contact with each other, for example.

<Second Dielectric Film on First Metal Film Side>

As illustrated inFIGS.25and26, the second dielectric film43-1located further on the first metal film41side than the light absorption film47is provided continuously across each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness, unlike the second dielectric film43-1of the third embodiment described above. In other words, the second dielectric film43-1is designed to have the same thickness in the first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view (seeFIG.25), the second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view (seeFIGS.25and26), and the third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view (seeFIG.26).

<First Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.25and26, the first dielectric film42-2located further on the second metal film47side than the light absorption film47includes the first part42-2awhich overlaps with the first part43-1aof the second dielectric film43-1(the photoelectric conversion region21aof the pixel3a) in plan view (seeFIG.25), the second part42-2bwhich overlaps with the second part43-1bof the second dielectric film43-1(the photoelectric conversion region21bof the pixel3b) in plan view and which is thicker than the first part42-2a(seeFIGS.25and26), and the third part42-2cwhich overlaps with the third part43-1cof the second dielectric film43-1(the photoelectric conversion region21cof the pixel3c) in plan view and which is thicker than the second part42-2b(seeFIG.26). In other words, the thickness of the first dielectric film42-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness increases in stages in order of the pixels3a,3b, and3c.

<Second Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.25and26, like the third embodiment described above, the second dielectric film43-2located further on the second metal film44side than the light absorption film47includes the first part43-2awhich overlaps with the first part42-2aof the first dielectric film42-2in plan view (seeFIG.25), the second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view and which is thinner than the first part43-2aof the second dielectric film43-2(seeFIGS.25and26), and the third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view and which is thinner than the second part43-2bof the second dielectric film43-2(seeFIG.26). In other words, the thickness of the second dielectric film43-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the first dielectric film42-2, the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.25and26, like the third embodiment described above, the light absorption film47of this embodiment is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c.

As illustrated inFIGS.25and26, the optical filter layer50D includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.25, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the light absorption film47, the first part42-2aof the first dielectric film42-2, and the first part43-2aof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.25and26, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.25, the third filter part51cincludes the third part43-1cof the second dielectric film43-1, the light absorption film47, the third part42-2cof the first dielectric film42-2, and the third part43-2cof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

Here, the second dielectric film43is provided on both the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. On the other hand, the first dielectric film42is provided only on one of the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. In the fourth embodiment, the first dielectric film42is provided on the second metal film44side of the light absorption film47, and is not provided on the first metal film41side of the light absorption film47.

As illustrated inFIGS.25and26, on the second metal film44side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratio of the thicknesses of the first dielectric film42-2and the second dielectric film43-2is the same as in the third embodiment described above. On the other hand, unlike the third embodiment described above, on the first metal film41side of the light absorption film47, the single-layer second dielectric film43-1is provided at the same thickness across the first to third filter parts51a,51b, and51c. In other words, like the resonance layer52C of the third embodiment described above, in the optical filter layer50D of the fourth embodiment, the thickness of a resonance layer52D between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface>

As illustrated inFIGS.25and26, on the first metal film41side of the light absorption film47, the surface layer part43-1S on the light absorption film47side of the second dielectric film43-1is flat across the pixels3(the photoelectric conversion regions21) adjacent to each other, unlike in the third embodiment described above.

As illustrated inFIGS.25and26, on the second metal film44side of the light absorption film47, the surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3(the photoelectric conversion regions21) adjacent to each other, as in the third embodiment described above. The second dielectric film43-2covers the entirety of the first dielectric film42-2across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded and the surface layer part43-2son the second metal film44side is a flat, even surface.

<<Main Effects of Fourth Embodiment>>

The solid-state image capturing device1D according to the fourth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Fifth Embodiment

A solid-state image capturing device1E according to a fifth embodiment of the present technique, illustrated inFIGS.27to29, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.27to29, the solid-state image capturing device1E according to the fifth embodiment of the present technique includes an optical filter layer50E instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. The difference between the optical filter layer50E of the fifth embodiment and the optical filter layer50C of the third embodiment described above is that the first dielectric film42-2in the optical filter layer50E is provided in a selective manner.

As illustrated inFIG.27, the optical filter layer50E of the fifth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50E of the fifth embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and two second dielectric films43-1and43-2as the second dielectric film43. In other words, the optical filter layer50E of the fifth embodiment includes a resonance layer52E in which the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer52E is provided between the first metal film41and the second metal film44.

As illustrated inFIG.27, each of the first metal film41, the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the second dielectric film43-2, and the second metal film44is provided across, for example, five of the pixels3, as in the third embodiment described above. On the other hand, unlike the third embodiment described above, the first dielectric film42-2is selectively provided in the second filter part51band the second filter part51cof the optical filter layer50E, and is not provided in the first filter part51a.

<First and Second Dielectric Films on First Metal Film Side>

As illustrated inFIGS.28and29, each of the second dielectric film43-1and the first dielectric film42-1located further on the first metal film41side than the light absorption film47is provided continuously across each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness, unlike the second dielectric film43-1and the first dielectric film42-1of the third embodiment described above.

In other words, the second dielectric film43-1includes the first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view. Each of the first to third parts43-1a,43-1b, and43-1cis designed to have the same thickness.

The first dielectric film42-1also includes the first part42-1awhich overlaps with the first part (the photoelectric conversion region21aof the pixel3a)43-1aof the second dielectric film43-1in plan view, the second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1(the photoelectric conversion region21cof the pixel3c) in plan view. Each of the first to third parts42-1a,42-1b, and42-1cis designed to have the same thickness.

<First and Second Dielectric Films on Second Metal Film Side>

As illustrated inFIGS.28and29, unlike the first dielectric film42-2of the third embodiment described above, the first dielectric film42-2located further on the second metal film44side than the light absorption film47does not include a first part which overlaps with the first part42-1a(the photoelectric conversion region21aof the pixel3a) of the first dielectric film42-1in plan view. Furthermore, as illustrated inFIGS.28and29, the first dielectric film42-2includes the second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-2cwhich overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view and which is thicker than the second part42-2b. In other words, the thickness of the first dielectric film42-2of the fifth embodiment is different for each of the pixels3band3c(the photoelectric conversion regions21band21c), and the thickness increases in stages in order of the pixels3band3c.

As illustrated inFIGS.28and29, unlike the second dielectric film43-2of the third embodiment described above, the second dielectric film43-2located further on the second metal film44side than the light absorption film47includes the first part43-2awhich overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21aof the pixel3a) in plan view, the second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view, and the third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view. In other words, the thickness of the second dielectric film43-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the first dielectric film42-2, the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.28and29, like the third embodiment described above, the light absorption film47of this embodiment is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c.

As illustrated inFIGS.28and29, the optical filter layer50E includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.28, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the first part42-1aof the first dielectric film42-1, the light absorption film47, and the first part43-2aof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.28and29, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the second part42-1bof the first dielectric film42-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.29, the third filter part51cincludes, in order from the first metal film41side, the third part43-1cof the second dielectric film43-1, the third part42-1cof the first dielectric film42-1, the light absorption film47, the third part42-2cof the first dielectric film42-2, and the third part43-2cof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

Here, the second dielectric film43is provided on both the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. On the other hand, the first dielectric film42is provided on one of the first metal film41side or the second metal film44side of the light absorption film47in the first filter part51a, and on both the first metal film41side and the second metal film44side of the light absorption film47in the second and third filter parts51band51c. In the fifth embodiment, in the first filter part51a, the first dielectric film42is provided on the first metal film41side of the light absorption film47, and is not provided on the second metal film44side of the light absorption film47.

As illustrated inFIGS.28and29, on the first metal film41side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratio of the thicknesses of the first dielectric film42-1and the second dielectric film43-1is the same. On the other hand, on the second metal film44side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42-2and the second dielectric film43-2are different.

Furthermore, on the first metal film41side of the light absorption film47, the total thicknesses h1a, h1b, and h1cof the first dielectric film42-1and the second dielectric film43-1in the first to third filter parts51a,51b, and51care designed to be the same.

Likewise, on the second metal film44side of the light absorption film47, the total thicknesses h2a, h2b, and h2cof the first dielectric film42-2and the second dielectric film43-2in the first to third filter parts51a,51b, and51care designed to be the same.

In other words, in the optical filter layer50E of the fifth embodiment as well, the thickness of the resonance layer52E between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface>

As illustrated inFIGS.28and29, on the first metal film41side of the light absorption film47, the surface layer part43-1S on the light absorption film47side of the second dielectric film43-1and the surface layer part42-1S on the light absorption film47side of the first dielectric film42-1are flat across the pixels3adjacent to each other.

As illustrated inFIGS.28and29, on the second metal film44side of the light absorption film47, the surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3(the photoelectric conversion regions21) adjacent to each other. The second dielectric film43-2covers the entirety of the first dielectric film42-2across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded and the surface layer part43-2son the second metal film44side is a flat, even surface.

<<Main Effects of Fifth Embodiment>>

The solid-state image capturing device1E according to the fifth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Sixth Embodiment

A solid-state image capturing device1F according to a sixth embodiment of the present technique, illustrated inFIGS.30to32, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.30to32, the solid-state image capturing device1F according to the sixth embodiment of the present technique includes an optical filter layer50F instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. Furthermore, in the optical filter layer50F of the sixth embodiment, the configuration on the first metal film41side of the light absorption film47and the configuration on the second metal film44side of the light absorption film47are inverted vertically from those in the optical filter layer50D of the fourth embodiment described above.

As illustrated inFIG.30, the optical filter layer50F of the sixth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50F of the sixth embodiment further includes one first dielectric film42-1as the first dielectric film42, and two second dielectric films43-1and43-2as the second dielectric film43. In other words, the optical filter layer50F of the fifth embodiment includes a resonance layer52F in which the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer52F is provided between the first metal film41and the second metal film44.

As illustrated inFIG.30, each of the first metal film41, the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, the second dielectric film43-2, and the second metal film44is provided across, for example, five of the pixels3, as in the third embodiment described above.

<Second Dielectric Film on First Metal Film Side>

As illustrated inFIGS.31and32, the second dielectric film43-1located further on the first metal film41side than the light absorption film47includes the first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view and which is thinner than the first part43-1a, and the third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view and which is thinner than the second part43-1b. In other words, the thickness of the second dielectric film43-1in this embodiment is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness decreases in stages in order of the pixels3a,3b, and3c.

<First Dielectric Film on First Metal Film Side>

As illustrated inFIGS.31and32, the first dielectric film42-1further on the first metal film41side than the light absorption film47includes the first part42-1awhich overlaps with the first part43-1aof the second dielectric film43-1in plan view, the second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1in plan view and which is thicker than the first part42-1aof the first dielectric film42-1, and the third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1in plan view and which is thicker than the second part42-1bof the first dielectric film42-1. In other words, the thickness of the first dielectric film42-1in this embodiment is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the second dielectric film43-1, the thickness increases in stages in order of the pixels3a,3b, and3c.

<Second Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.31and32, the second dielectric film43-2located further on the second metal film44side than the light absorption film47is provided continuously across each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness, unlike the second dielectric film43-2of the third embodiment described above. In other words, the second dielectric film43-2of this embodiment includes the first part43-2awhich overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21aof the pixel3a) in plan view, the second part43-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part43-2cwhich overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view. Each of the first to third parts43-2a,43-2b, and43-2cis designed to have the same thickness.

As illustrated inFIGS.31and32, like the fourth embodiment described above, the light absorption film47of this embodiment is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c.

As illustrated inFIGS.31and32, the optical filter layer50F includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.31, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the first part42-1aof the first dielectric film42-1, the light absorption film47, and the first part43-2aof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.31and32, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the second part42-1bof the first dielectric film42-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.32, the third filter part51cincludes the third part43-1cof the second dielectric film43-1, the third part42-1cof the first dielectric film42-1, the light absorption film47, the third part42-2cof the first dielectric film42-2, and the third part43-2cof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

Here, the second dielectric film43is provided on both the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. On the other hand, the first dielectric film42is provided only on one of the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. In the sixth embodiment, the first dielectric film42is provided on the first metal film41side of the light absorption film47, and is not provided on the second metal film44side of the light absorption film47.

As illustrated inFIGS.31and32, on the first metal film41side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42-1and the second dielectric film43-1are different. On the other hand, on the second metal film44side of the light absorption film47, the single-layer second dielectric film43-2is provided at the same thickness across the first to third filter parts51a,51b, and51c.

Furthermore, on the first metal film41side of the light absorption film47, the total thicknesses h1a, h1b, and h1cof the first dielectric film42-1and the second dielectric film43-1in the first to third filter parts51a,51b, and51care designed to be the same.

Likewise, on the second metal film44side of the light absorption film47, the thicknesses h2a, h2b, and h2cof the second dielectric film43-2in the first to third filter parts51a,51b, and51care designed to be the same.

In other words, like the resonance layer52C of the third embodiment described above, in the optical filter layer50F of the sixth embodiment, the thickness of the resonance layer52F between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface>

As illustrated inFIGS.31and32, on the first metal film41side of the light absorption film47, the surface layer part42-1S on the light absorption film47side of the first dielectric film42-1is flat across the pixels3adjacent to each other. The first dielectric film42-1covers the entirety of the second dielectric film43-1across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the second dielectric film43-1in the lower layer are embedded and the surface layer part42-1S on01the light absorption film47side (the second metal film44side) is a flat, even surface.

As illustrated inFIGS.31and32, on the second metal film44side of the light absorption film47, the surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3adjacent to each other.

<<Main Effects of Sixth Embodiment>>

The solid-state image capturing device1F according to the sixth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Seventh Embodiment

A solid-state image capturing device1G according to a seventh embodiment of the present technique, illustrated inFIGS.33to35, has basically the same configuration as the solid-state image capturing device1C according to the fourth embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.33to35, the solid-state image capturing device1G according to the seventh embodiment of the present technique includes an optical filter layer50G instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. The other configurations are generally the same as those described in the foregoing third embodiment.

As illustrated inFIG.33, the optical filter layer50G of the seventh embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50G of the seventh embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and one second dielectric film43-2as the second dielectric film43. In other words, the optical filter layer50G of the seventh embodiment includes a resonance layer52G in which the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer52G is provided between the first metal film41and the second metal film44.

As illustrated inFIG.33, each of the first metal film41, the second dielectric film43-1, the light absorption film47, the second dielectric film43-2, and the second metal film44is provided across, for example, five of the pixels3, as in the third embodiment described above.

Meanwhile, the first dielectric film42-2is selectively provided in the second filter part51band the second filter part51cof the optical filter layer50E, and is not provided in the first filter part51a, as in the fifth embodiment described above.

<First Dielectric Film on First Metal Film Side>

As illustrated inFIGS.34and35, the first dielectric film42-1located further on the first metal film41side than the light absorption film47is provided continuously across each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness. Furthermore, the first dielectric film42-1includes the first part42-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part42-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third part42-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view. The respective thicknesses of the first to third parts42-1a,42-1b, and42-1c(h1a, h1b, and h1c) are designed to be the same.

<First and Second Dielectric Films on Second Metal Film Side>

As illustrated inFIGS.34and35, the first dielectric film42-2located further on the second metal film44side than the light absorption film47does not include a first part which overlaps with the photoelectric conversion region21aof the pixel3ain plan view. Furthermore, as illustrated inFIGS.34and35, the first dielectric film42-2includes the second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-2cwhich overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view and which is thicker than the second part42-2bof the first dielectric film42-2. In other words, the thickness of the first dielectric film42-2of the seventh embodiment is different for each of the pixels3band3c(the photoelectric conversion regions21band21c), and the thickness increases in stages in order of the pixels3band3c.

As illustrated inFIGS.34and35, the second dielectric film43-2located further on the second metal film44side than the light absorption film47includes the first part43-2awhich overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21aof the pixel3a) in plan view, the second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view and which is thinner than the second dielectric film43-2a, and the third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view and which is thicker than the second part43-2bof the second dielectric film43-2. In other words, the thickness of the second dielectric film43-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and, opposite from the first dielectric film42-2, the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.34and35, like the third embodiment described above, the light absorption film47of this embodiment is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c.

As illustrated inFIGS.34and35, the optical filter layer50G includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.34, the first filter part51aincludes the first part42-1aof the first dielectric film42-1, the light absorption film47, and the first part43-2aof the second dielectric film43-2, in that order from the second metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.34and35, the second filter part51bincludes the second part42-1bof the first dielectric film42-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, in that order from the second metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.35, the third filter part51cincludes the third part42-1cof the first dielectric film42-1, the light absorption film47, the third part42-2cof the first dielectric film42-2, and the third part43-2cof the second dielectric film43-2, in that order from the second metal film41side, between the first metal film41and the second metal film44.

Here, the second dielectric film43is provided only on one of the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. On the other hand, the first dielectric film42is provided on one of the first metal film41side or the second metal film44side of the light absorption film47in the first filter part51a, and on both the first metal film41side and the second metal film44side of the light absorption film47in the second and third filter parts. In the seventh embodiment, in the first filter part51a, the first dielectric film42is provided on the second metal film44side of the light absorption film47, and is not provided on the second metal film44side of the light absorption film47.

As illustrated inFIGS.34and35, on the second metal film44side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42-2and the second dielectric film43-2are different. On the other hand, on the first metal film41side of the light absorption film47, the single-layer first dielectric film42-1is provided at the same thickness across the first to third filter parts51a,51b, and51c.

Furthermore, on the first metal film41side of the light absorption film47, the total thicknesses h1a, h1b, and h1cof the first dielectric film42-1and the second dielectric film43-1in the first to third filter parts51a,51b, and51care designed to be the same.

Likewise, on the second metal film44side of the light absorption film47, the total thicknesses h2a, h2b, and h2cof the first dielectric film42-2and the second dielectric film43-2in the first to third filter parts51a,51b, and51care designed to be the same.

In other words, in the optical filter layer50F of the seventh embodiment as well, the thickness of the resonance layer52F between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface>

As illustrated inFIGS.34and35, on the first metal film41side of the light absorption film47, the surface layer part42-1S on the light absorption film47side of the first dielectric film42-1is flat across the pixels3adjacent to each other.

As illustrated inFIGS.34and35, on the second metal film44side of the light absorption film47, the surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3adjacent to each other. The second dielectric film43-2covers the entirety of the first dielectric film42-2across the pixels3adjacent to each other such that the steps produced by the differences in the thickness of the first dielectric film42-2in the lower layer are embedded and the surface layer part43-2son the second metal film44side is a flat, even surface.

<<Main Effects of Seventh Embodiment>>

The solid-state image capturing device1G according to the seventh embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Eighth Embodiment

A solid-state image capturing device1H according to an eighth embodiment of the present technique, illustrated inFIGS.36to38, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.36to38, the solid-state image capturing device1H according to the eighth embodiment of the present technique includes an optical filter layer50H instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. Furthermore, in the optical filter layer50H of the eighth embodiment, the configuration on the first metal film41side of the light absorption film47and the configuration on the second metal film44side of the light absorption film47are inverted vertically from those in the optical filter layer50G of the seventh embodiment described above. The other configurations are generally the same as those described in the foregoing third embodiment.

As illustrated inFIG.36, the optical filter layer50H of the eighth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50H of the eighth embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and one second dielectric film43-1as the second dielectric film43. In other words, the optical filter layer50H of the eighth embodiment includes a resonance layer52H in which the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, and the first dielectric film42-2are stacked in that order from the first metal film41side. The resonance layer52H is provided between the first metal film41and the second metal film44.

As illustrated inFIG.36, each of the first metal film41, the second dielectric film43-1, the light absorption film47, the first dielectric film42-2, and the second metal film44is provided continuously across, for example, five of the pixels3. Meanwhile, the first dielectric film42-1is selectively provided in the second filter part51band the second filter part51cof the optical filter layer50H, and is not provided in the first filter part51a.

<First and Second Dielectric Films on First Metal Film Side>

As illustrated inFIGS.37and38, the second dielectric film43-1located further on the first metal film41side than the light absorption film47includes the first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view and which is thinner than the first part43-1a, and the third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view and which is thinner than the second part43-1b. In other words, the thickness of the second dielectric film43-1is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.37and38, the first dielectric film42-1located further on the first metal film41side than the light absorption film47does not include a first part which overlaps with the first part43-1aof the second dielectric film43-1(the photoelectric conversion region21aof the pixel3a) in plan view. Furthermore, as illustrated inFIGS.37and38, the first dielectric film42-1includes the second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1(the photoelectric conversion region21cof the pixel3c) in plan view and which is thicker than the second part42-1bof the first dielectric film42-1. In other words, the thickness of the first dielectric film42-1of the eighth embodiment is different for each of the pixels3band3c(the photoelectric conversion regions21band21c), and the thickness increases in stages in order of the pixels3band3c.

<First Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.37and38, the first dielectric film42-2located further on the second metal film44side than the light absorption film47is provided continuously across each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness.

Furthermore, the first dielectric film42-2includes the first part42-2awhich overlaps with the first part43-1aof the second dielectric film43-1(the photoelectric conversion region21aof the pixel3a) in plan view, the second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-2cwhich overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view. Each of the first to third parts42-2a,42-2b, and42-2cis designed to have the same thickness.

As illustrated inFIGS.37and38, the light absorption film47of this embodiment is provided continuously across the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same across the pixels3a,3b, and3c.

As illustrated inFIGS.37and38, the optical filter layer50H includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.37, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the light absorption film47, and the first part42-2aof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.37and38, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the second part42-1bof the first dielectric film42-1, the light absorption film47, and the second part42-2bof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIG.38, the third filter part51cincludes the third part43-1cof the second dielectric film43-1, the third part42-1cof the first dielectric film42-1, the light absorption film47, and the third part42-2cof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

Here, the second dielectric film43is provided only on one of the first metal film41side and the second metal film44side of the light absorption film47, in each of the first to third filter parts51ato51c. On the other hand, the first dielectric film42is provided on one of the first metal film41side or the second metal film44side of the light absorption film47in the first filter part51a, and on both the first metal film41side and the second metal film44side of the light absorption film47in the second and third filter parts. In the eighth embodiment, in the first filter part51a, the first dielectric film42is provided on the second metal film44side of the light absorption film47, and is not provided on the first metal film41side of the light absorption film47.

As illustrated inFIGS.37and38, on the first metal film41side of the light absorption film47, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42-1and the second dielectric film43-1are different. On the other hand, on the second metal film44side of the light absorption film47, the single-layer first dielectric film42-1is provided at the same thickness across the first to third filter parts51a,51b, and51c. Furthermore, on the first metal film41side of the light absorption film47, the total thicknesses h1a, h1b, and h1cof the first dielectric film42-1and the second dielectric film43-1in the first to third filter parts51a,51b, and51care designed to be the same.

Likewise, on the second metal film44side of the light absorption film47, the total thicknesses h2a, h2b, and h2cof the first dielectric film42-2and the second dielectric film43-2in the first to third filter parts51a,51b, and51care designed to be the same.

In other words, in the optical filter layer50H of the eighth embodiment as well, the thickness of the resonance layer52H between the first metal film41and the second metal film44is generally the same in each of the first to third filter parts51a,51b, and51c.

<Steps and Flat Surface>

As illustrated inFIGS.37and38, on the first metal film41side of the light absorption film47, the surface layer part43-1S on the light absorption film47side of the second dielectric film43-1and the surface layer part42-1S on the light absorption film47side of the first dielectric film42-1are flat across the pixels3adjacent to each other. The surface layer part42-1S on the light absorption film47side of the first dielectric film42-1is also flat across the pixels3adjacent to each other.

As illustrated inFIGS.37and38, on the second metal film44side of the light absorption film47, the surface layer part43-2S on the second metal film44side of the second dielectric film43-2is flat across the pixels3adjacent to each other.

<<Main Effects of Eighth Embodiment>>

The solid-state image capturing device1H according to the eighth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Ninth Embodiment

A solid-state image capturing device1I according to a ninth embodiment of the present technique, illustrated inFIGS.39to41, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.39to41, the solid-state image capturing device1I according to the ninth embodiment of the present technique includes an optical filter layer50I instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. The optical filter layer50I of the ninth embodiment differs from the optical filter layer50C of the third embodiment described above in terms of the location of the light absorption film47in the thickness direction (Z direction) in each filter part.

As illustrated inFIG.39, the optical filter layer50I of the ninth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50I of the ninth embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and one second dielectric film43-2as the second dielectric film43. In other words, the optical filter layer50I of the ninth embodiment includes a resonance layer52I in which the first dielectric film42-1, the light absorption film47, the first dielectric film42-2, and the second dielectric film43-2are stacked in that order from the first metal film41side. The resonance layer52I is provided between the first metal film41and the second metal film44.

<First Dielectric Film on First Metal Film Side>

As illustrated inFIGS.40and41, the first dielectric film42-1located further on the first metal film41side than the light absorption film47includes the first part42-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part42-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view and which is thicker than the first part42-1a, and the third part42-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view and which is thicker than the second part42-1b. In other words, the thickness of the first dielectric film42-1of the ninth embodiment is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness increases in stages in order of the pixels3a,3b, and3c.

<First and Second Dielectric Films on Second Metal Film Side>

As illustrated inFIGS.40and41, the first dielectric film42-2located further on the second metal film44side than the light absorption film47is provided on each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c) at a constant thickness. Furthermore, the first dielectric film42-2includes the first part42-2awhich overlaps with the first part42-1aof the first dielectric film42-1(the photoelectric conversion region21aof the pixel3a) in plan view, the second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-2cwhich overlaps with the third part42-1cof the first dielectric film42-1(the photoelectric conversion region21cof the pixel3c) in plan view. Each of the first to third parts42-2a,42-2b, and42-2cis designed to have the same thickness.

As illustrated inFIGS.40and41, the second dielectric film43-2located further on the second metal film41side than the light absorption film47includes the first part43-2awhich overlaps with the first part42-2aof the first dielectric film42-2in plan view, the second part43-2bwhich overlaps with the second part42-2bof the first dielectric film42-2in plan view and which is thinner than the first part43-2aof the second dielectric film43-2, and the third part43-2cwhich overlaps with the third part42-2cof the first dielectric film42-2in plan view and which is thinner than the second part43-2bof the second dielectric film43-2. In other words, the thickness of the second dielectric film43-2is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.40and41, the light absorption film47is provided for each of the pixels3a,3b, and3c. Although not limited thereto, the design value for the thickness of the light absorption film47is the same for each of the pixels3a,3b, and3c.

As illustrated inFIGS.40and41, the optical filter layer50I includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.40, the first filter part51aincludes the first part42-1aof the first dielectric film42-1, the light absorption film47, the first part42-2aof the first dielectric film42-2, and the first part43-2aof the second dielectric43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.40and41, the second filter part51bincludes the second part42-1bof the first dielectric film42-1, the light absorption film47, the second part42-2bof the first dielectric film42-2, and the second part43-2bof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44. The light absorption film47in the second filter part51bis located further on the second metal film44side than the light absorption film47in the first filter part51a. The second part42-2bof the first dielectric film42-2in the second filter part51bis also located further on the second metal film44side than the first part42-2aof the first dielectric film42-2in the first filter part51a.

As illustrated inFIG.41, the third filter part51cincludes the third part42-1cof the first dielectric film42-1, the light absorption film47, the third part42-3bof the first dielectric film42-2, and the third part43-3bof the second dielectric film43-2, in that order from the first metal film41side, between the first metal film41and the second metal film44. The light absorption film47in the third filter part51cis located further on the second metal film44side than the light absorption film47in the second filter part51b. The third part42-2cof the first dielectric film42-2in the third filter part51cis also located further on the second metal film44side than the second part42-2bof the first dielectric film42-2in the second filter part51b.

In other words, the position, in the thickness direction of the optical filter layer50I, of the light absorption film47is different in each of the first to third filter parts51a,51b, and51c. In this ninth embodiment, the position of the light absorption film47in each of the first to third filter parts51a,51b, and51cis displaced in stages toward the second metal film44side, in that order.

As illustrated inFIGS.40and41, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42and the second dielectric film43are different.

Furthermore, on the first metal film41side of the light absorption film47, total thicknesses ha, hb, and hc of the first dielectric film42-1and the second dielectric film43-1in the first to third filter parts51a,51b, and51c, respectively, are designed to be the same.

The solid-state image capturing device1I according to the ninth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Tenth Embodiment

A solid-state image capturing device1J according to a tenth embodiment of the present technique, illustrated inFIGS.42to44, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIGS.42to44, the solid-state image capturing device1J according to the tenth embodiment of the present technique includes an optical filter layer50J instead of the optical filter layer50C illustrated inFIGS.12to14described above in the third embodiment. In the optical filter layer50J of the tenth embodiment, the configuration on the first metal film41side of the light absorption film47and the configuration on the second metal film44side of the light absorption film47are inverted vertically from those in the optical filter layer50I of the ninth embodiment described above. Furthermore, in the tenth embodiment, the first filter part51ais configured not to include a first dielectric film on the first metal film41side of the light absorption film.

As illustrated inFIG.42, the optical filter layer50J of the tenth embodiment includes: the first metal film41provided on the second surface S2side (the light incidence surface side) of the semiconductor layer20with the insulating layer35located therebetween; the first dielectric film (high refraction film)42and the second dielectric film (low refraction film)43, which are arranged in the thickness direction of the semiconductor layer20side by side on the side of the first metal film41opposite from the side on which the semiconductor layer20is located, and which have different refractive indices from each other; the second metal film44provided on the side of the first and second dielectric films42and43opposite from the side on which the first metal film41is located; and the light absorption film47provided between the first dielectric film42and the second dielectric film43.

The optical filter layer50J of the tenth embodiment further includes two first dielectric films42-1and42-2as the first dielectric film42, and one second dielectric film43-1as the second dielectric film43. In other words, the optical filter layer50I of the tenth embodiment includes a resonance layer52J in which the second dielectric film43-1, the first dielectric film42-1, the light absorption film47, and the first dielectric film42-2are stacked in that order from the first metal film41side. The resonance layer52J is provided between the first metal film41and the second metal film44.

<First and Second Dielectric Films on First Metal Film Side>

As illustrated inFIGS.43and44, the second dielectric film43-1located further on the first metal film41side than the light absorption film47includes the first part43-1awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second part43-1bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view and which is thinner than the first part43-1a, and the third part43-1cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view and which is thinner than the second part43-1b. In other words, the thickness of the second dielectric film43-1is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness decreases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.43and44, the first dielectric film42-1located further on the first metal film41side than the light absorption film47does not include a first part which overlaps with the first part43-1aof the second dielectric film43-1(the photoelectric conversion region21aof the pixel3a) in plan view. Additionally, as illustrated inFIGS.43and44, the first dielectric film42-1is provided on each of the pixels3band3c(the photoelectric conversion regions21band21c) at a constant thickness. Furthermore, the first dielectric film42-1includes the second part42-1bwhich overlaps with the second part43-1bof the second dielectric film43-1(the photoelectric conversion region21bof the pixel3b) in plan view, and the third part42-1cwhich overlaps with the third part43-1cof the second dielectric film43-1(the photoelectric conversion region21cof the pixel3c) in plan view. Each of the second and third parts42-2band42-2cis designed to have the same thickness.

<First Dielectric Film on Second Metal Film Side>

As illustrated inFIGS.43and44, the first dielectric film42-2located further on the second metal film44side than the light absorption film47includes the first part42-2awhich overlaps with the first part43-1aof the second dielectric film43-1in plan view, the second part42-2bwhich overlaps with the second part42-1bof the first dielectric film42-1in plan view and which is thicker than the second part42-2aof the first dielectric film42-2, and the third part42-2cwhich overlaps with the third part43-1cof the first dielectric film42-1in plan view and which is thicker than the second part42-2bof the first dielectric film42-2. In other words, the thickness of the first dielectric film42-2of the tenth embodiment is different for each of the pixels3a,3b, and3c(the photoelectric conversion regions21a,21b, and21c), and the thickness increases in stages in order of the pixels3a,3b, and3c.

As illustrated inFIGS.43and44, the optical filter layer50J includes the first filter part51awhich overlaps with the photoelectric conversion region21aof the pixel3ain plan view, the second filter part51bwhich overlaps with the photoelectric conversion region21bof the pixel3bin plan view, and the third filter part51cwhich overlaps with the photoelectric conversion region21cof the pixel3cin plan view.

As illustrated inFIG.43, the first filter part51aincludes the first part43-1aof the second dielectric film43-1, the light absorption film47, and the first part42-2aof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44.

As illustrated inFIGS.43and44, the second filter part51bincludes the second part43-1bof the second dielectric film43-1, the second part42-1bof the first dielectric film42-1, the light absorption film47, and the second part42-1cof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44. The light absorption film47in the second filter part51bis located further on the first metal film41side than the light absorption film47in the first filter part51a.

As illustrated inFIG.44, the third filter part51cincludes the second part42-1bof the first dielectric film42-1, the second part42-1cof the first dielectric film42-1, the light absorption film47, and the third part42-2cbof the first dielectric film42-2, in that order from the first metal film41side, between the first metal film41and the second metal film44. The light absorption film47in the third filter part51cis located further on the first metal film41side than the light absorption film47in the second filter part51a. The third part42-1cof the first dielectric film42-1in the third filter part51cis also located further on the second metal film41side than the third part42-1cof the first dielectric film42-1in the second filter part51b. In other words, the position, in the thickness direction of the optical filter layer50J, of the light absorption film47is different in each of the first to third filter parts51a,51b, and51c. In this tenth embodiment, the position of the light absorption film47in each of the first to third filter parts51a,51b, and51cis displaced in stages toward the first metal film41side, in that order.

As illustrated inFIGS.43and44, in each of the first to third filter parts51a,51b, and51c, the ratios of the thicknesses of the first dielectric film42and the second dielectric film43are different.

Furthermore, on the first metal film41side of the light absorption film47, total thicknesses ha, hb, and hc of the first dielectric film42and the second dielectric film43in the first to third filter parts51a,51b, and51c, respectively, are designed to be the same.

The solid-state image capturing device1J according to the tenth embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

Eleventh Embodiment

A solid-state image capturing device1K according to an eleventh embodiment of the present technique, illustrated inFIG.45, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIG.45, the solid-state image capturing device1K according to the eleventh embodiment of the present technique further includes a color filter layer60. The color filter layer60is provided between the semiconductor layer20and the optical filter layer50C. The color filter layer60includes, for example, a color filter part provided for each of the pixels3(each of the photoelectric conversion regions21). Although not limited thereto, a red (R) first color filter part, a green (G) second color filter part, a blue (B) third color filter part, and the like are provided as the color filter parts, for example. In the eleventh embodiment, color filter parts having three colors, namely R, G, and B, for example, are provided. The color filter layer60separates the colors of the incident light incident from the light incidence surface side of the semiconductor chip2.

The solid-state image capturing device1K according to the eleventh embodiment provides effects similar to those of the solid-state image capturing device1C according to the third embodiment described above.

In addition, in the solid-state image capturing device1K according to the eleventh embodiment, color mixing can be eliminated by the color filter layer60.

Note that the color filter layer60can also be provided in the solid-state image capturing device according to the first to tenth embodiments described above.

Twelfth Embodiment

A solid-state image capturing device1L according to a twelfth embodiment of the present technique, illustrated inFIG.46, has basically the same configuration as the solid-state image capturing device1C according to the third embodiment described above, with the exception of the following configurations.

First, as illustrated inFIG.46, the solid-state image capturing device1L according to the twelfth embodiment of the present technique further includes an antireflection layer61that prevents incident light from being reflected at the first metal film41. The antireflection layer61is provided between the semiconductor layer20and the first metal film41. For example, a silicon oxide film having excellent light transmittance can be used as the antireflection layer61.

FIG.47is a diagram illustrating a correlation between transmittance and the presence or absence of the antireflection layer.

FromFIG.47, it can be seen that providing the antireflection layer61as in the twelfth embodiment has an effect of improving the transmittance, compared to when the antireflection layer is not provided.

The solid-state image capturing device1L according to the twelfth embodiment can achieve effects similar to those of the solid-state image capturing device1C according to the third embodiment described above, while improving the transmittance.

Note that the antireflection layer61can also be provided in the solid-state image capturing device according to the first to eleventh embodiment described above.

Thirteenth Embodiment

<<Example of Application in Electronic Device>>

The present technique (the technique according to the present disclosure) may be applied to various electronic devices, including image capturing devices such as digital still cameras and digital video cameras, mobile phones having image capturing functions, or other devices having image capturing functions, for example.

FIG.48is a diagram illustrating the overall configuration of an electronic device (e.g., a camera) according to the third embodiment of the present technique.

As illustrated inFIG.48, an electronic device100includes a solid-state image capturing device101, the optical lens102, a shutter device103, a driving circuit104, and a signal processing circuit105. This electronic device100corresponds to an embodiment in a case where one of the solid-state image capturing devices1A to1L according to the first to twelfth embodiments of the present technique is used as the solid-state image capturing device101in an electronic device (e.g., a camera).

The optical lens102forms an image of image light (incident light106) from a subject on an image capturing plane of the solid-state image capturing device101. As a result, signal charges are accumulated in the solid-state image capturing device101over a set period. The shutter device103controls a light emission period and a light shielding period for the solid-state image capturing device101. The driving circuit104supplies a drive signal for controlling a transfer operation of the solid-state image capturing device101and a shutter operation of the shutter device103. An operation of transferring a signal to the solid-state image capturing device101is performed according to the drive signal (timing signal) supplied from the driving circuit104. The signal processing circuit105performs various types of signal processing on signals (pixel signals) output from the solid-state image capturing device101. A video signal having been subjected to the signal processing is stored in a storage medium such as a memory or output to a monitor.

According to this configuration, the solid-state image capturing device101can achieve spectral separation at a low cost, and thus the electronic device100of the third embodiment can improve image quality at a low cost.

The electronic device100to which the solid-state image capturing device of the foregoing embodiments can be applied is not limited to a camera, and the solid-state image capturing device can be applied to other electronic devices as well. For example, the solid-state image capturing device may be applied in an image capturing device such as a camera module for a mobile device such as a mobile phone or a tablet terminal.

In addition to solid-state image capturing devices serving as image sensors as described above, the present technique can be applied in all types of light detection devices, including range sensors which measure distances, known as time of flight (ToF) sensors, and the like. A range sensor is a sensor that emits irradiated light toward an object, detects reflected light which returns when the irradiated light is reflected by a surface of the object, and calculates a distance to the object based on a time of flight from when the irradiated light is emitted to when the reflected light is received. The structure of the optical filter layer described above can be employed as the structure of a device isolation region in the range sensor.

The present technique may be configured as follows.(1) A light detection device including:a semiconductor layer in which a photoelectric conversion unit is provided for each of pixels;andan optical filter layer provided on a light incidence surface side of the semiconductor layer,whereinthe optical filter layer includes a first filter part and a second filter part, each provided for each of the pixels,each of the first and second filter parts includes:a first metal film provided on the light incidence surface side of the semiconductor layer;a first dielectric film and a second dielectric film which have different refractive indices and which are arranged in a thickness direction of the semiconductor layer side by side, on a side of the first metal film opposite from a side on which the semiconductor layer is located; anda second metal film provided on a side of the first and second dielectric films opposite from a side on which the first metal film is located, anda ratio of thicknesses of the first dielectric film and the second dielectric film is different in the first filter part and in the second filter part.(2)The light detection device according to (1), wherein a total thickness of the first dielectric film and the second dielectric is the same in the first filter part and in the second filter part.(3)The light detection device according to (1) or (2), wherein each of the first metal film, the first dielectric film, the second dielectric film, and the second metal film is provided across adjacent ones of the pixels.(4)The light detection device according to any one of (1) to (3), wherein the first dielectric film is provided further on a first metal film side than the second dielectric film, and has a higher refractive index than the second dielectric film.(5)The light detection device according to (4), wherein a surface layer part on a second dielectric film side of the first dielectric film has a step between adjacent ones of the pixels, anda surface layer part on a second metal film side of the second dielectric film is flat across adjacent ones of the pixels.(6)The light detection device according to any one of (1) to (3), wherein the first dielectric film is provided further on a second metal film side than the second dielectric film, and has a higher refractive index than the second dielectric film.(7)The light detection device according to (6), wherein a surface layer part on a first dielectric film side of the second dielectric film has a step between adjacent ones of the pixels, anda surface layer part on a second metal film side of the first dielectric film is flat across adjacent ones of the pixels.(8)The light detection device according to any one of (1) to (7), wherein the first dielectric film is a film containing any one of titanium oxide, tantalum oxide, silicon nitride, or hafnium oxide, and the second dielectric film is a film containing any one of silicon oxide or silicon oxynitride.(9)The light detection device according to any one of (1) to (8), wherein the first metal film is thicker than the second metal film.(10)(The light detection device according to any one of (1) to (9), wherein each of the first and second metal films is provided across adjacent ones of the pixels.(11)The light detection device according to any one of (1) to (10), wherein each of the first and second metal films is a film containing any one of aluminum, silver, copper, gold, chromium, or tungsten.(12)The light detection device according to any one of (1) to (11), further including:an insulating layer covering the second metal film on a side of the second metal film opposite from the side on which the first and second dielectric films are located.(13)The light detection device according to any one of (1) to (12), wherein the optical filter layer further includes a light absorption film provided between the first dielectric film and the second dielectric film.(14)The light detection device according to (1) to (13), wherein the light absorption film has a higher light absorption rate than the first and second dielectric films.(15)The light detection device according to (14), wherein in each of the first and second filter parts, each of the first and second dielectric films is provided on both the first metal film side and the second metal film side of the light absorption film.(16)The light detection device according to (13), wherein in each of the first and second filter parts, the second dielectric film is provided on both the first metal film side and the second metal film side of the light absorption film, andin each of the first and second filter parts, the first dielectric film is provided on one of the first metal film side or the second metal film side of the light absorption film.(17)The light detection device according to (13), wherein in each of the first and second filter parts, the second dielectric film is provided on both the first metal film side and the second metal film side of the light absorption film, andin the first filter part, the first dielectric film is provided on one of the first metal film side or the second metal film side of the light absorption film, and in the second filter part, the first dielectric film is provided on both the first metal film side and the second metal film side of the light absorption film.(18)The light detection device according to (13), wherein in each of the first and second filter parts, the second dielectric film is provided on one of the first metal film side or the second metal film side of the light absorption film, andin the first filter part, the first dielectric film is provided on both the first metal film side and the second metal film side of the light absorption film.(19)The light detection device according to (13), wherein a position of the light absorption film in a thickness direction of the optical filter layer is different in the first filter part and in the second filter part.(20)The light detection device according to any one of (13) to (19), further including:a color filter layer provided between the semiconductor layer and the optical filter layer.(21)The light detection device according to any one of (13) to (20), further including:an antireflection film provided between the semiconductor layer and the first metal film.(22)The light detection device according to any one of (1) to (21), wherein the light absorption film is a film containing any one of amorphous silicon, monocrystalline silicon, polycrystal silicon, germanium, silicon germanium, indium-gallium-arsenic, titanium, tungsten, or copper.(23) A light detection device including:a semiconductor layer in which a photoelectric conversion unit is provided; andan optical filter layer provided on a light incidence surface side of the semiconductor layer,whereinthe optical filter layer includes:a first metal film provided on the light incidence surface side of the semiconductor layer;a first dielectric film and a second dielectric film which have different refractive indices and which are arranged in a thickness direction of the semiconductor layer side by side, on a side of the first metal film opposite from a side on which the semiconductor layer is located;a second metal film provided on a side of the first and second dielectric films opposite from a side on which the first metal film is located; anda light absorption film provided between the first dielectric film and the second dielectric film.(24) An electronic device including:the light detection device according to any one of (1) to (23);an optical lens that forms an image of image light from a subject on an image capturing plane of the light detection device; anda signal processing circuit that performs signal processing on a signal output from the semiconductor layer.

The scope of the present technique is not limited to the exemplary embodiments illustrated in the drawings and described above, and includes all embodiments which have the object of the present technique and provide equivalent effects. Furthermore, the scope of the present technique is not limited to the combinations of features of the invention defined by the claims, and can be defined by all desired combinations of specific features among all the features disclosed.

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