JP2014003190A - Solid state image sensor and image pick-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent color mixing in a solid state image sensor when it includes W pixels.SOLUTION: In the solid state image sensor, a color filter layer CF having a plurality of color filters 21 of different colors is placed on a plurality of photoelectric conversion parts 17 arranged two-dimensionally on a substrate 1, so that each color filter 21 is in one and one correspondence with each photoelectric conversion part 17. The photoelectric conversion part 17 consists of a pixel electrode 12 sectioned for each pixel, a photoelectric conversion film 14 common to all pixels, and a counter electrode 16 disposed to face the pixel electrode 12 while sandwiching the photoelectric conversion film 14. The optical path length dfrom the lower surface of the color filter layer CF to the upper surface of the photoelectric conversion film 14 is 1.2 μm or less, and the optical path length dof the thickness of the photoelectric conversion film 14 is 1.4 μm or less.

Description

  The present invention relates to a solid-state imaging device including a photoelectric conversion unit that generates charges when irradiated with light, and an imaging apparatus including the solid-state imaging device.

  As an image sensor used for a digital still camera, a digital video camera, a mobile phone camera, an endoscope camera, etc., pixels including photodiodes are arranged on a semiconductor substrate such as a silicon (Si) chip, Solid-state imaging devices (so-called CCD sensors and CMOS sensors) that acquire signal charges corresponding to photoelectrons generated in a photodiode with a CCD type or CMOS type readout circuit are widely known.

  In recent years, pixel miniaturization of solid-state imaging devices has been advanced. When a pixel is miniaturized, the number of photons incident on each pixel decreases, so that there is a problem that the sensitivity of an image generally decreases. Therefore, in order to achieve high sensitivity, it has been proposed to introduce a white pixel (white pixel) into the color filter array and to include a WRGB color filter (Patent Document 1, Patent Document 2, etc.).

  As a conventional imaging device, a configuration in which a photoelectric conversion unit is formed together with a readout circuit in a semiconductor substrate such as silicon is common. However, since the photoelectric conversion unit and the readout circuit are provided in the substrate, a decrease in the aperture ratio of the photoelectric conversion unit and a decrease in the light collection efficiency have become problems with miniaturization.

  In addition, B and R light is detected by an image pickup device having a structure in which a three-layer photoelectric conversion film is stacked on a semiconductor substrate on which a signal readout circuit is formed, or a photodiode in the semiconductor substrate, and a photoelectric sensor above the silicon substrate is detected. A laminated type image sensor that simultaneously receives light of three colors with one pixel, such as an image sensor (Patent Document 3) having a structure in which G light is detected by a conversion element, has been proposed. The structure for receiving light has a problem that it is difficult to manufacture and the cost increases.

  On the other hand, a photoelectric conversion part including a pair of electrodes and a photoelectric conversion film sandwiched between these electrodes is provided above a silicon substrate on which a signal readout circuit and the like are formed, and this photoelectric conversion part is the same as in the case of a conventional solid-state imaging device. By providing the color filter layer, the charge generated in the photoelectric conversion film through each color filter is transferred from one of the pair of electrodes to the silicon substrate and accumulated, and a signal corresponding to the accumulated charge is transmitted to the silicon substrate. In recent years, a stacked solid-state imaging device that reads with a signal readout circuit formed on a substrate has attracted attention. By forming the photoelectric conversion film as a single film common to all pixels, the light receiving area of each pixel is increased (the aperture ratio is increased) compared to a conventional solid-state imaging device in which a photoelectric conversion unit and a readout circuit are provided in the substrate. Therefore, high sensitivity is expected (Patent Documents 4, 5, etc.).

JP 2004-304706 A JP 2011-243817A JP 2007-103786 A JP 2008-263178 A JP 2011-187663 A

  Even in the stacked solid-state imaging device described in Patent Documents 4 and 5, etc., further miniaturization and higher sensitivity can be achieved by applying the filter array including the W pixels described in Patent Documents 1 and 2 and the like. It is thought that you can.

  However, when the W pixel is applied to the stacked solid-state imaging device, it has been clarified by the inventors that another problem unique to an aperture ratio of 100% occurs. The problem will be described in detail below.

  When the inventor simply includes a filter layer including a W pixel in a multilayer image sensor, light incident on the W filter is changed to another color filter due to a refractive index difference between the W filter and the other color filters. It has been found that the problem of color mixing arises from the phenomenon of bending to the side, leading to a decrease in S / N. FIG. 1 shows the wavelength dependence of the refractive index for each color for the WRGB filter. As shown in FIG. 1, the W filter has a smaller refractive index and less wavelength dependency than the R, G, and B filters. In general, light is bent from a medium having a low refractive index toward a medium having a high refractive index.

  FIG. 2 shows a light intrusion region (upward to the right in FIG. 2) between the filters 90B when B light is incident, 90G when G light is incident, and 90R when R light is incident when a general Bayer RGB filter 90 is used. It is a schematic plan view showing a region indicated by oblique lines. FIG. 3 shows the light between the filters of 95B when the B light is incident, 95G when the G light is incident, and 95R when the R light is incident, in the case of the WRGB filter 95 in which one of the RGB filters of the RGB Bayer arrangement is changed to a W filter. FIG. 4 is a schematic plan view showing an intrusion region (a region indicated by an oblique line rising to the right in FIG. 3). Here, the size of each filter and the pixel coincide.

  As shown in FIG. 2, when the RGB filter 90 is used, when B light is incident, only the B pixel transmits light, and the refractive index of the G filter is smaller than that of the B filter in the blue wavelength range. Absent. Further, when R light is incident, only the R pixel transmits light at 90R, and since the refractive index of the G filter is smaller than that of the R filter in the red wavelength region, the light does not spread. On the other hand, at 90G when G light is incident, only the G pixel transmits light, but since the refractive index of the G filter is smaller than that of the R filter and B filter in the green wavelength region, the light spreads. Accordingly, only light that has passed through the G filter enters the surrounding pixels.

  On the other hand, as shown in FIG. 3, when the WRGB filter 95 is used, light is transmitted through the B pixel and the W pixel when the B light is incident 95B, and the refractive index of the W filter is smaller than the R filter in the blue wavelength region. The spread from the W filter to the R filter occurs. In addition, when R light is incident, light is transmitted through the R pixel and the W pixel, and the light spreads because the refractive index of the W filter is smaller than that of the B filter in the red wavelength region. Further, at G light incidence 95G, light is transmitted through the G pixel and W pixel, and the light spreads because the refractive index of the W filter and G filter is smaller than that of the R filter and B filter in the green wavelength region. That is, when only the RGB filter is used, only light leaks from the G pixel, whereas when the W filter is used, very complicated light intrusion occurs between the pixels.

  When these intrusion lights are received by the photoelectric conversion unit and signal charges are generated, color mixing occurs. When the W filter is not used, the color of the intrusion light is determined, so it is possible to reduce the color mixture by signal processing or the like. However, when the W filter is used, the color mixture becomes very complicated. Therefore, reduction by signal processing or the like is difficult. Therefore, it is desirable if the refractive indexes of all the color filters can be made uniform so that such light intrusion does not occur. However, in practice, it is extremely difficult to adjust the refractive index while adjusting the absorption rate of the color filter for color separation.

  Next, the structure of the light receiving unit will be described. 4 and 5 show the configuration of a conventional solid-state imaging device. FIG. 4 is a schematic pixel cross-sectional view of a front-illuminated structure of a conventional solid-state image sensor, and FIG. 5 is a schematic cross-sectional view of a pixel of a back-illuminated structure of a conventional solid-state image sensor. 4 and 5, the upper side of the drawing is the light incident side.

  As shown in FIG. 4, the front-illuminated imaging element includes a wiring layer 106 and an interlayer insulating layer 105 on a semiconductor substrate 101 on which a photoelectric conversion unit 117 and a signal readout circuit 111 are formed. Usually, a color filter layer is formed above the interlayer insulating layer 105. The photoelectric conversion unit 117 is disposed across an element isolation region in which the signal readout circuit 111 and the like are formed for each pixel. A broken line A in FIG. 4 is a boundary of one pixel unit with the photoelectric conversion unit 117 as the center.

  As shown in FIG. 5, the back-illuminated image sensor receives light from the side opposite to the wiring layer 106 and the interlayer insulating layer 105 formed on the semiconductor substrate 101 on which the photoelectric conversion unit 117 and the signal readout circuit 111 are formed. The top and bottom of the surface irradiation type is reversed, and a support substrate 102 is separately provided on the surface that is not on the light incident side. Note that the photoelectric conversion unit 117 is arranged with an element isolation region in which the signal readout circuit 111 and the like are formed for each pixel, and the broken line A in FIG. 5 is centered on the photoelectric conversion unit 117 as in the surface irradiation type. Is a boundary of one pixel unit. In this case, since the color filter layer is formed on the surface of the substrate 101 opposite to the surface on which the wiring layer is formed, the wiring layer 106 and the interlayer insulation are provided between the photoelectric conversion unit 117 and the color filter layer. The layer 105 is not present. Unlike the surface irradiation type, since these layers are not between the photoelectric conversion part and the color filter layer, the surface irradiation type can receive vignetting light in the wiring layer, etc. The light receiving rate is greatly improved.

  FIG. 6 is a plan view schematically showing a relationship between a pixel region and a light receiving region (a planar view region of a photoelectric conversion unit) of a conventional solid-state imaging device. The same applies to both the front-side irradiation type and the back-side irradiation type, and the light-receiving region (the region indicated by the left-upward oblique line in FIG. 6) of the photoelectric conversion unit 117 with respect to the pixel region (the region indicated by the dotted line A in FIG. 6). A little smaller. This is because it is necessary to provide the photoelectric conversion unit 117 and the signal readout circuit 111 on the same substrate as described above, and to separate the photoelectric conversion unit 117 for each pixel.

  Next, the configuration of the stacked solid-state imaging device will be briefly described. FIG. 7 is a schematic cross-sectional view of a pixel of a multilayer imaging device that is an object of the present invention, and FIG. 8 is a schematic plan view showing the relationship between the pixel region of the multilayer imaging device and a light receiving region (a planar view region of the photoelectric conversion unit). FIG.

  As shown in FIG. 7, in the multilayer image pickup device, a wiring layer 6 and an interlayer insulating layer 5 are formed on a semiconductor substrate 1 on which a signal readout circuit and the like are formed, and the pixels partitioned for each pixel on the wiring layer 6. A photoelectric conversion film 14 and a counter electrode 16 provided in common to all the pixels are provided on the electrode 12 and the pixel electrode 12. In general, the color filter layer is disposed on the counter electrode 16 via a protective film. The size of one pixel is determined according to the repetition period of the two-dimensionally arranged pixel electrodes. When the photoelectric conversion unit is at the center, an area of one pixel unit is determined with the center line between the pixel electrodes as a boundary, as indicated by a broken line A in FIG.

  Since the photoelectric conversion film 14 and the counter electrode 16 are formed of a film common to all the pixels in the multilayer imaging device having the above-described configuration, light is irradiated also to the photoelectric conversion film 14 in the gap region between the pixel electrodes 12. Then, a signal charge is generated. The signal charge generated in the gap region between the pixel electrodes 12 is collected by each pixel electrode with the center line between the pixel electrodes indicated by the broken line A as a boundary. The aperture ratio is 100% because the area of one pixel region and the area where the photoelectric conversion unit can collect signal charges are the same.

  That is, as shown in FIG. 8, the pixel area delimited by the pixel boundary indicated by the broken line A and the light receiving area (area indicated by the left-upward oblique line) match.

  9 and 10 are diagrams showing the light intrusion region in the WRGB filter shown in FIG. 3 superimposed on the plan views of the conventional solid-state image pickup device and multilayer image pickup device shown in FIGS. 6 and 8, respectively.

As shown in FIG. 9, in the conventional solid-state imaging device, the light intrusion area (upward-slashed portion) of the W pixel adjacent pixel does not overlap with the light-receiving area (upward-left diagonal line) of the adjacent pixel (R, B pixel). I understand that. That is, even if light enters another pixel due to the low refractive index of the W filter, color mixture does not occur because it does not enter the photoelectric conversion unit of the other pixel. On the other hand, as shown in FIG. 10, since the aperture ratio is 100% in the case of the multilayer image sensor, it can be seen that light transmitted through the W filter enters the light receiving area of other pixels and color mixing occurs. .
Therefore, when a filter layer having a W filter is applied to a multilayer image sensor, a new color mixture that does not occur in a conventional solid-state image sensor occurs, and thus this color mixture is suppressed so that S / N does not decrease. This is a big issue.

  In view of the above circumstances, the present invention includes a solid-state imaging device that includes a filter layer having a W filter and can suppress a decrease in S / N due to color mixing, and the solid-state imaging device. An object is to provide an imaging device.

The solid-state imaging device of the present invention includes a pixel electrode partitioned on a substrate on a substrate, a photoelectric conversion film that generates a signal charge according to the amount of incident light, and a pixel electrode facing the pixel electrode across the photoelectric conversion film. In a solid-state imaging device having an imaging unit in which a plurality of pixels having a photoelectric conversion unit including a provided counter electrode are arranged two-dimensionally,
The photoelectric conversion film and the counter electrode are formed in a common film shape common to all pixels,
A protective film is provided on the counter electrode,
On the protective film, color filter layers having different color filters are disposed so that each color filter corresponds to each photoelectric conversion unit,
A color filter layer having a plurality of different colors as a color filter, a predetermined color filter that transmits only wavelengths in a predetermined color region, and a white filter that transmits wavelengths in the entire visible light region arranged adjacent to the predetermined color filter And having a refractive index difference between the predetermined color filter and the white filter in at least a visible light region other than the wavelength of the predetermined color region,
The optical path length d ₁ from the bottom surface of the color filter layer to the top surface of the photoelectric conversion film is 1.2 μm or less,
The optical path length d ₂ of the thickness of the photoelectric conversion film is equal to or less than 1.4 [mu] m.

  Here, the wavelength that is 50% or more of the transmittance of the wavelength having the maximum transmittance among the wavelengths in the visible light region that is transmitted through the filter is the “transmitting” wavelength. The wavelength is not transmitted.

  In the solid-state imaging device of the present invention, the photoelectric conversion film preferably contains an organic material.

When the refractive index difference between the white color filter and the predetermined color filter is Δn, between Δn and the optical path lengths d ₁ (μm) and d ₂ (μm) in the entire visible light wavelength region where the predetermined color filter does not transmit,
Δn × (d ₁ + d ₂ ) ² <2.0
It is preferable that this relationship is established.

  It is preferable that the predetermined color is any one of blue, green and red.

  As the predetermined color filter that transmits only the wavelength of the predetermined color region, a blue filter that transmits only the wavelength of the blue region, a green filter that transmits only the wavelength of the green region, and a red filter that transmits only the wavelength of the red region are provided. It is preferable.

  As the predetermined color filter that transmits only the wavelength of the predetermined color region, a yellow filter that transmits only the wavelength of the yellow region, a magenta filter that transmits only the wavelength of the magenta region, and a cyan filter that transmits only the wavelength of the cyan region. You may prepare.

  A MOS transistor circuit is formed on the substrate to read a signal corresponding to the charge generated in the photoelectric conversion unit. The MOS transistor circuit includes a charge storage unit electrically connected to the photoelectric conversion unit, and a potential of the charge storage unit. A reset transistor that resets the signal to a reset potential and an output transistor that outputs a signal corresponding to the potential of the charge storage unit. The reset transistor and the output transistor collect the polarity of the carrier generated in the photoelectric conversion unit. The polarity is preferably opposite to the charge.

  It is preferable that a functional layer for suppressing dark current is provided between the photoelectric conversion film and the pixel electrode.

  An image pickup apparatus according to the present invention includes the solid-state image pickup element.

According to the solid-state image pickup device and the image pickup apparatus of the present invention, the stacked solid-state image pickup device including the photoelectric conversion film in a film common to all pixels includes the color filter layer including the W filter, and performs photoelectric conversion from the bottom surface of the color filter layer. Since the optical path length d ₁ to the upper surface of the film is 1.2 μm or less and the thickness optical path length d ₂ of the photoelectric conversion film is 1.4 μm or less, color mixing that may occur when a W filter is provided is suppressed, and the S / N The reduction can be prevented, and the effect of increasing the sensitivity by providing the W filter can be sufficiently obtained.

The figure which shows the wavelength dependence of the refractive index of each color filter The figure for demonstrating the light oozing in the conventional RGB filter The figure for demonstrating the light oozing in a WRGB filter Cross-sectional schematic diagram showing a part of a conventional solid-state imaging device of surface irradiation type Cross-sectional schematic diagram showing part of a conventional back-illuminated solid-state image sensor A plan view showing a pixel and a light receiving region (photoelectric conversion unit) of a conventional solid-state imaging device Cross-sectional schematic diagram showing part of a multilayer imaging device Plan view showing pixels and light-receiving area (photoelectric conversion unit) of stacked image sensor FIG. 6 is a plan view of the conventional solid-state imaging device shown in FIG. FIG. 8 is a plan view in which a WRGB filter is superimposed on the plan view of the multilayer image sensor shown in FIG. 1 is a schematic cross-sectional view showing a part of a solid-state imaging device according to an embodiment of the present invention. Diagram illustrating an optical path length d ₁ dependency of the filter bottom of the color mixing ratios to the photoelectric conversion layer top Diagram illustrating an optical path length d ₂ dependence of the thickness of the photoelectric conversion layer of the color mixing rate The figure which shows the pixel size dependence of the color mixture rate The figure which shows typically a leak to the adjacent pixel of the light which permeate | transmitted W filter The figure which shows typically a leak to the adjacent pixel of the light which permeate | transmitted the W filter in case refractive index difference (DELTA) n is 0.2. The figure which shows typically a leak to the adjacent pixel of the light which permeate | transmitted the W filter in case refractive index difference (DELTA) n is 0, 4. Diagram illustrating an optical path length d ₂ dependency of color mixing rate when the refractive index difference Δn and the optical path length by changing the d ₁ Shows a _{Δn × (d 1 + d 2} ) 2 dependence of color mixing rate A circuit diagram showing composition of one pixel of a solid-state image sensing device of an embodiment The figure which shows the whole structure of the solid-state image sensor concerning embodiment of this invention.

Hereinafter, embodiments of a solid-state imaging device of the present invention will be described with reference to the drawings.
FIG. 11 is a cross-sectional view schematically showing a part of the imaging unit (pixel region) of the solid-state imaging device 100 of the present embodiment.

  As shown in FIG. 11, the imaging unit of the solid-state imaging device 100 includes a semiconductor circuit board 1, an interlayer insulating layer 5 on the semiconductor circuit board 1, and a wiring layer 6 disposed in the insulating layer 5. A plurality of pixel electrodes (lower electrodes) 12 arranged in a dimension, a photoelectric conversion film 14 made of an organic material formed in common on the plurality of pixel electrodes 12, and a plurality formed on the photoelectric conversion film 14 And a counter electrode 16 facing the pixel electrode. A transparent protective film 18 is laminated on the counter electrode 16, and a color filter layer CF including a plurality of different color filters 21 is provided on the protective film 18. In FIG. 11, only the white (W) filter 21 w and the blue (B) filter 21 b are shown, but the color filter layer CF further includes a red (R) filter and a green (G) filter in FIG. 3. A WRGB filter 95 like the arrangement shown.

  One pixel electrode 12, the photoelectric conversion film 14 on the pixel electrode 12, and the counter electrode 16 constitute one photoelectric conversion unit 17. The photoelectric conversion film on the gap between the adjacent pixel electrodes also contributes to the photoelectric conversion, and the center line between the adjacent pixel electrodes (broken line A in FIG. 11) becomes the boundary between the adjacent photoelectric conversion elements.

  The color filter layer CF corresponds to one color filter for one photoelectric conversion unit, and is arranged so that both areas coincide in plan view. The area of the photoelectric conversion unit in plan view and the color filter in plan view The areas at are the same.

  The surface layer of the semiconductor circuit substrate 1 is provided with a signal readout circuit 11 including an accumulation unit for accumulating charges generated in each photoelectric conversion unit 17 and an output circuit for outputting a voltage corresponding to the signal charge of the accumulation unit. One pixel unit 20 includes one photoelectric conversion unit 17, a signal readout circuit 11 formed on a substrate surface layer portion below the photoelectric conversion unit 17, and each color filter 21 disposed on the photoelectric conversion unit. In FIG. 11, only the W pixel 20W provided with the W filter and the B pixel 20B provided with the B filter are shown.

  The pixel electrode 12 is a thin film electrode divided for each photoelectric conversion portion 17 and is formed of a transparent or opaque conductive material such as ITO, aluminum, titanium nitride, or the like. The pixel electrode 12 collects charges generated in the photoelectric conversion film 14 for each photoelectric conversion unit 17. The pixel electrode 12 of each photoelectric conversion unit 17 is electrically connected to the signal readout circuit 11 through a connection unit 7 made of a conductive material so as to penetrate the insulating layer 5.

  The counter electrode 16 is an electrode for applying a voltage to the photoelectric conversion film 14 disposed between the pixel electrode 12 and generating an electric field in the photoelectric conversion film 14, and is formed in a film shape common to all pixels. Has been. Since the counter electrode 16 is provided on the light incident surface side of the photoelectric conversion film 14 and needs to be transmitted through the counter electrode 16 and incident on the photoelectric conversion film 14, the counter electrode 16 is transparent to the incident light. It is formed from a conductive material such as ITO.

  The photoelectric conversion film 14 is composed of an organic photoelectric conversion film or an inorganic photoelectric conversion film that absorbs incident light and generates charges according to the absorbed light quantity. By using the photoelectric conversion film 14 as a film common to all the pixels, the aperture ratio can be set to 100% and high sensitivity can be obtained. A function such as a charge blocking layer that suppresses the injection of charges from the electrode to the photoelectric conversion film 14 between the photoelectric conversion film 14 and the counter electrode 16 or between the photoelectric conversion film 14 and the pixel electrode 12. A layer may be provided.

  Note that in the case where a functional layer is provided between the pixel electrode and the photoelectric conversion film, the functional layer is located below the light incident surface of the photoelectric conversion layer and thus does not contribute to color mixing. On the other hand, when a functional layer is provided between the counter electrode and the photoelectric conversion film, color mixing spreads even in this functional layer. Therefore, the thickness of the functional layer must be as thin as possible to satisfy the optical path length described later. Preferably, a functional layer is provided only on the pixel electrode side, and no functional layer is provided between the counter electrode and the photoelectric conversion film.

  Since the photoelectric conversion film 14 has an optical path length of 1.4 μm or less as will be described later, the photoelectric conversion film 14 has a large absorption coefficient so that sufficiently high sensitivity is exhibited even if the film thickness is small, and the absorbed light is signal charge. It is necessary to use a material having a high quantum efficiency for conversion into. Since the silicon film cannot perform sufficient photoelectric conversion with such a thin thickness, it is preferable to use an organic material in order to achieve a sufficiently large absorption coefficient even if it is thin.

  In order to obtain high quantum efficiency, a structure including a p-type organic semiconductor and an n-type organic semiconductor is particularly preferable among organic materials. Exciton dissociation efficiency can be increased by joining a p-type organic semiconductor and an n-type organic semiconductor to form a donor-acceptor interface. For this reason, the photoelectric conversion layer of the structure which joined the p-type organic semiconductor and the n-type organic semiconductor expresses high photoelectric conversion efficiency. In particular, a photoelectric conversion layer in which a p-type organic semiconductor and an n-type organic semiconductor are mixed is preferable because the junction interface is increased and the photoelectric conversion efficiency is improved.

  A p-type organic semiconductor (compound) is a donor organic semiconductor, and when it is an organic semiconductor, it is a compound semiconductor that is mainly represented by a hole-transporting organic compound and has a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic semiconductor as long as it is an electron-donating organic compound.

  Although it does not specifically limit as a p-type semiconductor, For example, a triarylamine compound, a benzidine compound, a pyrazoline compound, a styrylamine compound, a hydrazone compound, a triphenylmethane compound, a carbazole compound, a polysilane compound, a thiophene compound, a phthalocyanine compound, a cyanine compound , Merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives ), A metal complex having a nitrogen-containing heterocyclic compound as a ligand can be used. Not limited to this, as described above, any organic compound having an ionization potential smaller than that of the organic compound used as the n-type (acceptor) compound may be used as the donor organic semiconductor.

  An n-type organic semiconductor (compound) is an acceptor semiconductor, and is typically a compound semiconductor represented by an electron transport compound and having a property of easily accepting electrons. More specifically, an n-type semiconductor refers to a compound having a higher electron affinity when two compounds are used in contact with each other. Therefore, any compound can be used as the acceptor compound as long as it is an electron-accepting compound.

  The n-type semiconductor is not particularly limited. For example, a condensed aromatic carbocyclic compound (naphthalene derivative, anthracene derivative, phenanthrene derivative, tetracene derivative, pyrene derivative, perylene derivative, fluoranthene derivative), nitrogen atom, oxygen atom, sulfur atom 5- to 7-membered heterocyclic compounds (for example, pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole , Oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, tria Ropyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds And a metal complex having as a ligand. However, the present invention is not limited thereto, and as described above, any compound having an electron affinity higher than that of the compound used as the p-type (donor) compound may be used as the acceptor semiconductor.

  Any organic dye may be used as the p-type organic semiconductor or the n-type organic semiconductor, but preferably a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye (including zero methine merocyanine (simple merocyanine)), 3 Nuclear merocyanine dye, 4-nuclear merocyanine dye, rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye, azamethine dye, coumarin dye, arylidene dye, anthraquinone dye, tri Phenylmethane dye, azo dye, azomethine dye, spiro compound, metallocene dye, fluorenone dye, fulgide dye, perylene dye, perinone dye, phenazine dye, phenothiazine color , Quinone dye, diphenylmethane dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye, quinophthalone dye, phenoxazine dye, phthaloperylene dye, diketopyrrolopyrrole dye, dioxane dye, porphyrin dye, chlorophyll dye, phthalocyanine dye, And metal complex dyes and condensed aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives).

  As the n-type organic semiconductor, it is particularly preferable to use fullerene or a fullerene derivative having excellent electron transport properties. Fullerene represents fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C80, fullerene C82, fullerene C84, fullerene C90, fullerene C96, fullerene C240, fullerene 540, mixed fullerene, and fullerene nanotubes. It represents a compound having a substituent added thereto.

  The substituent for the fullerene derivative is preferably an alkyl group, an aryl group, or a heterocyclic group. More preferably, the alkyl group is an alkyl group having 1 to 12 carbon atoms, and the aryl group and the heterocyclic group are preferably a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring. , Biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran Ring, benzimidazole ring, imidazopyridine ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring, phenanthroline , Thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, or phenazine ring, more preferably a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, pyridine ring, imidazole ring, oxazole ring, or A thiazole ring, particularly preferably a benzene ring, a naphthalene ring, or a pyridine ring. These may further have a substituent, and the substituents may be bonded as much as possible to form a ring. In addition, you may have a some substituent and they may be the same or different. A plurality of substituents may be combined as much as possible to form a ring.

  When the photoelectric conversion layer contains fullerene or a fullerene derivative, electrons generated by photoelectric conversion can be quickly transported to the pixel electrode or the counter electrode via the fullerene molecule or the fullerene derivative molecule. When fullerene molecules or fullerene derivative molecules are connected to form an electron path, the electron transport property is improved, and high-speed response of the photoelectric conversion element can be realized. For this purpose, it is preferable that 40% or more of fullerene or fullerene derivative is contained in the photoelectric conversion layer. However, when there are too many fullerenes or fullerene derivatives, the p-type organic semiconductor is reduced, the junction interface is reduced, and the exciton dissociation efficiency is lowered.

In the photoelectric conversion layer, as a p-type organic semiconductor mixed with fullerene or a fullerene derivative, when a triarylamine compound described in Japanese Patent No. 4213832 is used, high absorption and high quantum efficiency can be expressed even in a thin film, Particularly preferred. If the ratio of fullerene or fullerene derivative in the photoelectric conversion layer is too large, the amount of the triarylamine compound is reduced and the amount of incident light absorbed is reduced. As a result, the photoelectric conversion efficiency is reduced, so that the fullerene or fullerene derivative contained in the photoelectric conversion layer preferably has a composition of 85% or less. With this configuration, d ₂ can be set to 1.0 to 1.2 over the entire visible light range while expressing high sensitivity in the photoelectric conversion layer.

  In particular, when the photoelectric conversion film includes an organic material, the protective film 18 has a function of protecting the photoelectric conversion layer from deterioration factors such as water molecules and oxygen. The protective film 18 has a function of protecting the photoelectric conversion layer by preventing intrusion of a factor that degrades the performance of the photoelectric conversion layer contained in a solution such as an organic solvent or plasma in each manufacturing process of the image sensor 10. Bear. In addition, after the image pickup device 10 is manufactured, intrusion of factors such as water molecules and oxygen that degrade the performance of the photoelectric conversion layer is prevented to prevent the performance deterioration of the photoelectric conversion layer over a long period of storage and long-term use. To do. Further, incident light (visible light) reaches the photoelectric conversion film 14 through the protective film 18. For this reason, the protective film 18 is transparent to light having a wavelength detected by the photoelectric conversion element 17 and visible light. The protective film 18 preferably has a light transmittance of 60% or more, more preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more.

  The thickness of the protective film is approximately 50 to 1000 nm, but is determined within a range that satisfies the following conditions. However, when the thickness of the protective film 18 is less than 50 nm, there is a possibility that the barrier property is lowered and the resistance of the color filter to the developer is lowered. On the other hand, a thick protective film 18 leads to an increase in color mixture as will be described later. Therefore, the protective film 18 is preferably thin.

  The protective film is particularly preferably an inorganic material film formed in a vapor phase. It is easier to obtain a film having a higher protection performance with an inorganic material than with an organic material even with a thin film. The vapor deposition method can provide a dense film as compared with other film formation methods, and thus high protection performance can be obtained even with a thin film. Among the vapor deposition methods, the CVD method is particularly preferable because a dense film can be obtained. Further, since the film forming speed is high, it is suitable for manufacturing. Among the CVD methods, the ALCVD method is particularly suitable for reducing the thickness of the protective film because a particularly dense film can be obtained.

Among the inorganic materials, aluminum oxide (AlOx), silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON) are preferable from the viewpoints of performance and optical path length reduction. In particular, SiON formed by CVD can change the refractive index and protection performance by changing the film formation conditions and adjusting the ratio of O and N, and high protection performance can be obtained with a short optical path length.
Further, AlOx formed by the ALCVD method can obtain high protection performance even with a film thickness of 100 nm or less, which is almost an order of magnitude smaller than other film forming methods.
Therefore, for example, a laminated film of 100 nm or less AlOx formed by ALCVD and 100 to 500 nm formed by CVD is very preferable from the viewpoint of optical path length and protection performance.

  A functional layer such as an antireflection layer or a color filter adhesion enhancing layer may be provided between the protective film and the color filter. However, even when these layers are used, it is necessary to use a thin film so that the optical path length from the bottom surface of the color filter layer to the top surface of the photoelectric conversion film is 1.2 μm or less, as will be described later.

In the present embodiment, a functional layer for improving the function of the photoelectric conversion element, specifically, a charge blocking layer for reducing dark current is provided between the photoelectric conversion film 14 and the pixel electrode. Yes.
In the imaging device of the present invention, since the photoelectric conversion film is thin, there is a high risk of dark current increase due to a short circuit or a leak, so that the dark current suppression effect by providing the charge blocking layer is high. .

The color filter layer CF is disposed and formed so that each filter 21 is located at a position facing each pixel electrode 12 on the protective film 18.
As shown in FIG. 3, the color filter layer CF includes a color filter that transmits light of different wavelengths of R, G, and B and a W filter that transmits the entire visible light. Each of the R, G, and B filters is formed of an organic material containing a red / blue / green pigment or dye.

Each color filter is generally formed by exposing and developing a color resist with ultraviolet rays. The color resist is composed of pigments of various colors, a photo-curing resin, a viscosity adjusting agent, and the like. The refractive index of the color filter after pattern formation by exposure and development is determined by the main component pigment and the photo-curing resin. Therefore, as shown in FIG. 1, the refractive index of the color filter differs for each color of WRGB, and also differs depending on the wavelength of incident light.
FIG. 1 shows an example of a WRGB filter. However, since each color filter of a color filter layer generally uses a photo-curing resin, the refractive index difference for each color itself is the same as that in FIG. 0 to 0.4.

In the present invention, the optical path length d ₁ from the bottom surface of the color filter layer CF to the photoelectric conversion film 14 is 1.2 μm or less, and the optical path length d ₂ of the thickness of the photoelectric conversion film 14 is 1.4 μm or less. And

In the present embodiment, the protective film 18 and the counter electrode 16 are provided between the color filter layer CF and the photoelectric conversion film 14, but other layers may be included. The optical path length is represented by the product of the spatial distance and refractive index, wherein the optical path length d ₁ is to have a layer of a plurality of different refractive index, it is represented by the sum of the optical path length of each layer. For example, in the configuration shown in FIG. 11, when the thickness of the protective film 18 is t ₁ , the refractive index is n ₁ , the thickness of the counter electrode 16 is t ₂ , and the refractive index is n ₂ , the optical path length d ₁ = n _1. t ₁ + n ₂ · t ₂ .

The optical path length of the thickness of the photoelectric conversion film 14, that is, the optical path length d ₂ from the top surface to the bottom surface of the photoelectric conversion film 14 is expressed by d ₂ = n ₃ · t ₃ from the thickness t ₃ and the refractive index n _3. It is.

  The inventor has conducted various studies and found that the color mixing ratio can be sufficiently reduced at least within the above range. The investigation that has led to the finding that the above range is preferable will be described below.

  In a general color filter manufactured by mixing a dye or the like in a resist, the refractive index difference between W and R, G, and B is about 0.4 or less as shown in FIG. . If the difference in refractive index is sufficiently small, almost no color mixing occurs. According to the study by the present inventors, if the difference in refractive index is less than 0.1, color mixing that causes a problem did not occur. In view of this, the difference in refractive index between the W pixel and the other pixels was assumed to be about 0.1 to 0.4. In addition, the case where incident light enters vertically from above the filter was studied.

Considering that the penetration of light transmitted through the W filter into adjacent pixels spreads away from the bottom surface of the filter, the distance from the bottom surface of the filter to the bottom surface of the photoelectric conversion film was examined.
In the imaging device having the configuration shown in FIG. 11, when the refractive index difference between two adjacent filters of different colors is 0.1 and 0.4, the photoelectric conversion from the low refractive index filter to the high refractive index filter side is performed. The color mixing ratio due to the light incident on the part was examined by changing d ₁ and d ₂ . Here, the pixel size is 3 μm.

Regarding the refractive index difference Δn = 0.4, the leakage of light from the W pixel to the B pixel when R light (650 nm) was incident was examined. Since the R light transmittance of the B filter is almost 0, it is considered that all signals of the B pixel are caused by leakage. Therefore, the signal charge generated in the B pixel divided by the pixel size (3 μm) was plotted as a color mixture ratio.
As Δn = 0.1, the leakage of light from the W pixel to the R pixel when B light (450 nm) was incident was examined. Since the B light transmittance of the R filter is almost 0, it is considered that all signals of the R pixel are caused by leakage. Therefore, the signal mixture generated by dividing the signal charge generated in the R pixel by the pixel size (3 μm) was plotted as the color mixture ratio.

FIG. 12 is a graph showing the dependence of the color mixture ratio on d ₁ when d ₂ is 1.4 μm. As shown in FIG. 12, the color mixture rate hardly changed when d ₁ was 1.2 μm or less, but rapidly increased when d ₁ exceeded 1.2 μm.

FIG. 13 is a graph showing the dependency of the color mixture rate on d ₂ when d ₁ is 1.2 μm. As shown in FIG. 13, the color mixing ratio is hardly changed by _{d 2} is 1.4 [mu] m or less, and rapidly increase exceeds 1.4 [mu] m.

Note that, when d ₁ = 1.2 μm and d ₂ = 1.4 μm, and the change in the color mixture rate was examined by changing the pixel size, as shown in FIG. 14, the color mixture rate did not depend much on the pixel size. It was. From this, it became clear that the soaking of light occurred only in a small area near the pixel boundary.

  From the above results, it became clear that the light leakage in the solid-state imaging device is as shown in FIG. FIG. 15 is a diagram schematically illustrating leakage of light transmitted through the W filter to adjacent pixels in the solid-state imaging device. In FIG. 15, the thickness is indicated by the optical path length, not the actual film thickness. The light transmitted through the W color filter gradually leaks to the adjacent pixels in the protective film and the photoelectric conversion film due to the difference in refractive index between the W color filter and the adjacent color filter. However, the leakage does not increase linearly with respect to the depth direction, but the leakage region is narrow in the upper part near the color filter, and the leakage region spreads rapidly as the depth increases.

Of the light leaked in this way, the light absorbed by the photoelectric conversion layer of the adjacent pixel causes color mixing. However, since light penetrates in the depth direction while being absorbed by the photoelectric conversion layer, if the leakage region is the same, a large amount of signal charge is generated at the upper part of the photoelectric conversion layer, and the signal charge generated at the lower part of the photoelectric conversion layer is Few. That is, it is important to narrow the leak region above the photoelectric conversion layer. This indicates that when the value of d ₁ is large, the leakage area at the upper part of the photoelectric conversion layer becomes large and the color mixture increases drastically. As shown in FIG. 12, d ₁ is 1.2 μm or less. It is necessary to reduce color mixing.

On the other hand, regarding the lower part of the photoelectric conversion layer, the area of the leakage region increases nonlinearly as d ₂ increases. As shown in FIG. 13, when d ₂ exceeds 1.4 μm, the color mixture increases explosively, so d ₂ needs to be 1.4 μm or less.

That is, according to the present invention, in a stacked imaging device including a photoelectric conversion film in a film shape common to all pixels on a semiconductor circuit substrate, a color filter layer including a W filter is provided, from the bottom surface of the color filter layer to the upper surface of the photoelectric conversion film. of 1.2μm below the optical path length _{d 1,} and the thickness optical path length _{d 2} of the photoelectric conversion layer and below 1.4 [mu] m. As a result, color mixing that may occur when the W filter is provided can be suppressed to prevent S / N reduction, and the effect of increasing sensitivity by providing the W filter can be sufficiently obtained.

  Furthermore, it has been found that the light leakage area increases as the refractive index difference Δn between the filters increases. 16 and 17 are diagrams schematically showing leakage of light transmitted through the W filter to adjacent pixels when the refractive index difference Δn is 0.2, 0, and 4, respectively. As shown in FIGS. 16 and 17, the leakage area increases as the refractive index difference Δn increases. From FIG. 16 and FIG. 17, when the refractive index difference Δn is increased, the leakage region is spread so as to increase rapidly.

Considering that there is the above correlation between the refractive index difference Δn and the leakage region, it is conceivable that appropriate ranges exist for d ₁ and d ₂ according to the refractive index difference Δn. However, as shown in FIGS. 16 and 17, the leakage region has a complicated shape that expands as it goes in the depth direction, and light is absorbed in the photoelectric conversion film so that there is a slight amount below the photoelectric conversion unit. Since this is a complicated phenomenon such as the arrival of only light, an appropriate correlation between the refractive index difference Δn and d ₁ and d ₂ for controlling color mixing cannot be uniquely determined.

Therefore, the inventor first obtained data of the color mixing ratio when d ₁ , d ₂ and the refractive index difference Δn were changed as shown in FIG. FIG. 18 shows only the case where Δn = 0.1, 0.2, 0.3, 0.4 when d ₁ = 1.2 μm, but d1 is 0.2, Similarly, data is acquired for the case of 0.6 μm. However, since data values overlap and visibility decreases, it is not shown in FIG. Next, an appropriate relational expression (for example, Δn × (d ₁ + d ₂ )) is predicted between d ₁ , d ₂ and the refractive index difference Δn for the obtained data, and the color mixing rate and By plotting the relationship, a condition under which color mixing can be more effectively suppressed under conditions where d ₁ is 1.2 μm or less and d ₂ is 1.4 μm or less was searched. As a result, it was found that color mixing can be more effectively suppressed by setting Δn × (d ₁ + d ₂ ) ² to 2.0 or less as shown in FIG.

FIG. 19 is based on the result of FIG. 18, and in the case where d ₁ is 1.2 μm or less and d ₂ is 1.4 μm or less, Δn × (d ₁ + d ₂ ) ² is plotted on the horizontal axis and the color mixing ratio is plotted on the vertical axis. Is a graph in which is plotted. As shown in FIG. 19, when Δn × (d ₁ + d ₂ ) ² changes greatly from 2.0 as a boundary, and Δn × (d ₁ + d ₂ ) ² becomes 2.0 or more, 2 It has been found that the increase in color mixture becomes remarkable as compared with the case of less than 0.0. That is,
Δn × (d ₁ + d ₂ ) ² <2.0
It was found that color mixing can be suppressed more effectively.

In the above embodiment, the color filter array is an array in which one of G of RGB Bayer arrays is replaced with W. However, the color filter array is not limited to the above array and can be arbitrarily changed. is there. Further, instead of R, G, and B, a complementary color filter may be provided, or a color filter layer including four types of color filters of yellow, magenta, cyan, and white may be provided. Even in that case, since white generally has the smallest refractive index, light oozes out from the white pixel to other pixels in the same manner, so that the optical path lengths d ₁ and d ₂ are controlled as in the above embodiment. As a result, the influence of light oozing can be suppressed, and a high S / N image can be acquired.

  FIG. 20 is a circuit diagram illustrating the signal readout circuit 11 in each pixel unit 20 and the relationship between the circuit unit 11 and the photoelectric conversion unit 17. As shown in FIG. 20, in the signal readout circuit 11, an output transistor 32, a reset transistor 33, and a selection transistor 34 are formed. The output transistor 32, the reset transistor 33, and the selection transistor 34 are each composed of an n-channel MOS transistor. The photoelectric conversion unit 17 and the gate of the output transistor 32 are electrically connected, and this node is referred to as a floating diffusion FD (hereinafter simply referred to as FD). In FIG. 11, the signal readout circuit 11 is shown as one region, but in reality, the above-described elements are formed in this region.

  In the pixel unit 20 of the present embodiment, a bias voltage is applied to the pixel electrode 12 such that holes out of the charges generated in the photoelectric conversion film 14 move to the pixel electrode 12 and electrons move to the counter electrode 16. Applied. As a bias voltage, a voltage (5 V) higher than the power supply voltage Vdd of the readout circuit (voltage supplied to the drain of the output transistor in FIG. 20, for example, 3 V) so that the photoelectric conversion film 14 exhibits sufficiently high sensitivity. It is desirable to use about -20V, for example 10V).

  FD is a node including an n-type impurity region electrically connected to the pixel electrode 12. The FD has a capacitance due to the parasitic capacitance of the photoelectric conversion unit 17 and each transistor. Since the potential of the FD changes according to the amount of charges collected by the pixel electrode 12, the FD functions as a charge storage unit.

  The output transistor 32 converts the charge signal accumulated in the FD into a voltage signal and outputs it to the signal line. The gate terminal of the output transistor 32 is electrically connected to the FD, and the drain terminal is connected to the power supply voltage Vdd of the solid-state imaging device. The source terminal of the output transistor 32 is connected to the drain terminal of the selection transistor 34. The pixel unit 20 in the present embodiment is a circuit having a so-called three-transistor configuration in which the FD, the pixel electrode 12 of the photoelectric conversion unit 17, and the gate terminal of the output transistor 32 are electrically connected directly.

  The reset transistor 33 resets the potential of the FD to a reference potential. The FD is electrically connected to the drain terminal of the reset transistor 33, the reset power source is connected to the source terminal, and the voltage RD is supplied. When the reset pulse RS applied to the gate terminal of the reset transistor 33 becomes high level, the reset transistor 33 is turned on, and electrons are injected from the source to the drain of the reset transistor 33. Then, due to the injection of electrons, the potential of the FD drops and the potential of the FD is reset to the reference potential. The selection transistor 34 has a source terminal connected to the signal line, and selectively outputs a signal output from the output transistor 32 of each pixel to a signal line provided for each column. . When the selection pulse RW applied to the gate terminal of the selection transistor 34 becomes a high level, the selection transistor 34 is turned on, whereby a signal output from the output transistor 32 of each pixel is output to the signal line.

  In the solid-state imaging device of the above-described embodiment, the signal readout circuit 11 is configured by the reset transistor 33, the output transistor 32, and the selection transistor 34 are n-channel MOS transistors, and holes are collected by the pixel electrode 12. However, the present invention is not limited thereto, and the reset transistor 33, the output transistor 32, and the selection transistor 34 are configured by p-channel MOS transistors, and electrons are collected by the pixel electrode 12, and a charge signal corresponding to the amount of the electrons is obtained. Reading may be performed by the signal reading circuit 11 configured by a p-channel MOS transistor.

  As in the above embodiment, holes are collected by the pixel electrode 12 and read out by the signal readout circuit 11 constituted by an n-channel MOS transistor, or electrons are collected by the pixel electrode 12 as described above. When this is configured to read out the signal readout circuit 11 configured by a p-channel MOS transistor, the electron is collected by the pixel electrode and read out by a signal readout circuit configured from an n-channel MOS transistor. As compared with, the number of saturated electrons can be increased, and the dynamic range of the W pixel which is easily saturated can be increased. In the photodiode formed in the conventional silicon substrate, since the signal readout circuit and the photodiode are formed in the same substrate, the polarity of the readout circuit and the polarity of the collected charge could not be reversed. .

  FIG. 21 is a diagram illustrating an overall configuration of the solid-state imaging device 100 of the present embodiment. As shown in FIG. 21, the solid-state imaging device 100 of the present embodiment includes a vertical driver 121, a control unit 122, a signal processing circuit 123, a horizontal driver 124, an LVDS 125, a serial conversion unit 126, a pad 127, and the like. And a pixel region (corresponding to an imaging unit) in which a plurality of pixel units 20 shown in FIG. 11 are arranged two-dimensionally. In the pixel region of FIG. 21, only the signal readout circuit 11 of the pixel unit 20 is schematically shown.

  The control unit 122 includes a timing generator and the like, outputs the frame synchronization signal VD and the row synchronization signal HD, and controls the operations of the vertical driver 121 and the horizontal driver 124 to control the charge signal in the pixel unit 20. It controls reading and the like.

  The vertical driver 121 outputs a reset pulse RS and a selection pulse RW to the signal readout circuit 11 based on the frame synchronization signal VD and the row synchronization signal HD output from the control unit 122, and a reset operation in the signal readout circuit 11. And the charge signal reading operation.

  The signal processing circuit 123 is provided corresponding to each column of the signal readout circuit 11. The signal processing circuit 123 includes an ADC circuit that performs correlated double sampling (CDS) processing on the signals output from the corresponding columns and converts the processed signals into digital signals. The signal processed by the signal processing circuit 123 is stored in a memory provided for each column.

  The horizontal driver 124 performs control for sequentially reading out signals for one row of the pixel unit 20 stored in the memory of the signal processing circuit 123 and outputting the signals to the LVDS 125.

  The LVDS 125 transmits a digital signal in accordance with LVDS (low voltage differential signaling). The serial conversion unit 126 converts an input parallel digital signal into a serial signal and outputs it. The pad 127 is an interface used for input / output with the outside.

  In the present embodiment, the configuration in which the micro lens is not provided on the color filter has been described, but the micro lens may be provided on the color filter.

  The solid-state imaging device of the above-described embodiment can be used for various imaging devices. Examples of the imaging device include a digital camera, a digital video camera, an electronic endoscope, and a camera-equipped mobile phone.

DESCRIPTION OF SYMBOLS 1 Semiconductor circuit board 11 Signal readout circuit 12 Pixel electrode 14 Photoelectric conversion film 16 Opposite electrode 17 Photoelectric conversion part 18 Protective film 20 Pixel part 21 Color filter 32 Output transistor 33 Reset transistor 34 Selection transistor 100 Solid-state image sensor FD Floating diffusion CF Color filter layer

Claims (9)

A pixel electrode partitioned on a substrate unit; a photoelectric conversion film that generates a signal charge according to the amount of incident light; and a counter electrode provided to face the pixel electrode with the photoelectric conversion film interposed therebetween In a solid-state imaging device having an imaging unit in which a plurality of pixels having a photoelectric conversion unit are two-dimensionally arranged,
The photoelectric conversion film and the counter electrode are formed in a common film shape common to all the pixels,
A protective film is provided on the counter electrode,
On the protective film, color filter layers having different color filters are arranged so that each color filter corresponds to each photoelectric conversion unit,
The color filter layer, as the different color filters, transmits a predetermined color filter that transmits only a wavelength in a predetermined color region, and a wavelength that extends over the entire visible light region disposed adjacent to the predetermined color filter. A white filter that has a refractive index difference between the predetermined color filter and the white filter at least in a visible light region other than the wavelength of the predetermined color region,
An optical path length d ₁ from the bottom surface of the color filter layer to the top surface of the photoelectric conversion film is 1.2 μm or less;
A solid-state imaging device optical path length d ₂ of the thickness of the photoelectric conversion film is equal to or less than 1.4 [mu] m.   The solid-state imaging device according to claim 1, wherein the photoelectric conversion film includes an organic material. Assuming that the refractive index difference between the white filter and the predetermined color filter is Δn, between Δn and the optical path lengths d ₁ (μm) and d ₂ (μm) in a visible light wavelength region that the predetermined color filter does not transmit. ,
Δn × (d ₁ + d ₂ ) ² <2.0
The solid-state imaging device according to claim 1, wherein the relationship is established.   The solid-state imaging device according to any one of claims 1 to 3, wherein the predetermined color is any one of blue, green, and red.   As the predetermined color filter that transmits only the wavelength of the predetermined color region, a blue filter that transmits only the wavelength of the blue region, a green filter that transmits only the wavelength of the green region, and a red filter that transmits only the wavelength of the red region The solid-state imaging device according to claim 1, further comprising:   As the predetermined color filter that transmits only the wavelength of the predetermined color region, a yellow filter that transmits only the wavelength of the yellow region, a magenta filter that transmits only the wavelength of the magenta region, and a cyan filter that transmits only the wavelength of the cyan region The solid-state imaging device according to claim 1, further comprising:   A MOS transistor circuit is formed on the substrate to read out a signal corresponding to the charge generated in the photoelectric conversion unit. The MOS transistor circuit includes a charge storage unit electrically connected to the photoelectric conversion unit, and the charge storage unit. A reset transistor that resets the potential of the unit to a reset potential, and an output transistor that outputs a signal corresponding to the potential of the charge storage unit. The reset transistor and the output transistor have a carrier polarity in the photoelectric conversion unit. The solid-state imaging device according to any one of claims 1 to 6, wherein the solid-state imaging device has a polarity opposite to that of the generated charges to be collected.   8. The solid-state imaging device according to claim 1, wherein a functional layer for suppressing dark current is provided between the photoelectric conversion film and the pixel electrode. 9.   An image pickup apparatus comprising the solid-state image pickup device according to claim 1.