SOLID-STATE IMAGE SENSOR FILTER AND SOLID-STATE IMAGE SENSOR

A solid-state image sensor filter includes: a light-incident surface on which light is incident; an infrared filter located on a side of a photoelectric conversion element on which the light-incident surface is disposed; and a barrier layer located on a side of the infrared filter on which the light-incident surface is disposed, the barrier layer being provided to suppress transmission of an oxidation source to thereby prevent the infrared filter from being oxidized.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a solid-state image sensor filter and a solid-state image sensor having the solid-state image sensor filter.

Discussion of the Background

Solid-state image sensors such as CMOS image sensors and CCD image sensors include photoelectric conversion elements that convert the intensity of light into an electrical signal. A first example of a solid-state image sensor includes color filters and color photoelectric conversion elements for respective colors, and the photoelectric conversion elements for respective colors detect respective color light (for example, see PTL 1). A second example of a solid-state image sensor includes an organic photoelectric conversion element and an inorganic photoelectric conversion element, and the photoelectric conversion elements detect respective color light without using a color filter (for example, see PTL 2).

The photoelectric conversion elements have an absorption band not only in the visible light range, but also in the infrared light range including near-infrared light. A third example of a solid-state image sensor includes an infrared cut-off filter disposed on a photoelectric conversion element, and cuts off infrared light that may otherwise be detected by the photoelectric conversion element, to prevent it from reaching the photoelectric conversion element, to thereby improve the accuracy of detection of visible light by the photoelectric conversion element. The materials constituting the infrared cut-off filter may be, for example, anthraquinone-based compounds, phthalocyanine-based compounds, cyanine-based compounds, immonium-based compounds, or diimmonium-based compounds (for example, see PTLs 1, 3, and 4).

A fourth example of a solid-state image sensor includes an infrared pass filter disposed on an infrared photoelectric conversion element, and cuts off visible light that may otherwise be detected by the infrared photoelectric conversion element, to prevent it from reaching the infrared photoelectric conversion element, to thereby improve the accuracy of detection of infrared light by the infrared photoelectric conversion element. Materials constituting the infrared pass filter may be, for example, black colorants such as bisbenzofuranone-based pigments, azomethine-based pigments, perylene-based pigments, or azo-based dyes (for example, PTLs 5 and 6).

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a solid-state image sensor filter for use with a photoelectric conversion element includes color microlenses which have a light-incident surface on which light is incident and collect the light incident on the light-incident surface toward a photoelectric conversion element to be combined with the solid-state image sensor filter, an infrared filter positioned between the color microlenses and the photoelectric conversion element, and a barrier layer formed between the color microlenses and the infrared filter such that transmission of an oxidation source that oxidizes the infrared filter is suppressed.

According to another aspect of the present invention, a solid-state image sensor filter for use with a photoelectric conversion element includes color microlenses which have a light-incident surface on which light is incident and collect the light incident on the light-incident surface toward a photoelectric conversion element to be combined with the solid-state image sensor filter, and an infrared filter positioned between the color microlenses and the photoelectric conversion element. A laminate structure formed between the color microlenses and the infrared filter has an oxygen transmittance of 5.0 cc/m2/day/atm or less.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

With reference toFIGS. 1 and 2, a first embodiment of a solid-state image sensor filter and a solid-state image sensor will be described.FIG. 1is a schematic configuration diagram in which layers in part of a solid-state image sensor are separately illustrated. The structures shown inFIGS. 1 and 2are example structures of a solid-state image sensor. The solid-state image sensor includes respective color filters, in which a gap may be provided between the color filters as shown inFIG. 1, or may not be provided as shown inFIG. 2.

As shown inFIG. 1, the solid-state image sensor includes a solid-state image sensor filter10and a plurality of photoelectric conversion elements11. The solid-state image sensor filter10includes color filters12R,12G, and12B, an infrared cut-off filter13as an example of an infrared filter, a barrier layer14, and respective color microlenses15R,15G, and15B.

The color filters12R,12G, and12B are disposed between the photoelectric conversion elements11for three colors and the infrared cut-off filter13. The barrier layer14is disposed between the infrared cut-off filter13and the color microlenses15R,15G, and15B. The infrared cut-off filter13is disposed on a light-incident side of the color filters12R,12G, and12B. The barrier layer14is disposed on a light-incident side of the infrared cut-off filter13.

The photoelectric conversion elements11for three colors are composed of a red photoelectric conversion element11R, a green photoelectric conversion element11G, and a blue photoelectric conversion element11B. The solid-state image sensor includes a plurality of red photoelectric conversion elements11R, a plurality of green photoelectric conversion elements11G, and a plurality of blue photoelectric conversion elements11B.FIG. 1illustrates one repeating unit of the photoelectric conversion elements11in the solid-state image sensor.

The color filters for three colors are composed of a red filter12R, a green filter12G, and a blue filter12B. The red filter12R is disposed on a light-incident side of the red photoelectric conversion element11R. The green filter12G is disposed on a light-incident side of the green photoelectric conversion element11G. The blue filter12B is disposed on a light-incident side of the blue photoelectric conversion element11B.

As shown inFIG. 2, the color filters12R,12G, and12B have thicknesses T12which may be substantially the same or different from each other. That is, the thicknesses of the red filter12R, the green filter12G, and the blue filter12B may not necessarily be the same. The thickness T12of the color filters12R,12G, and12B is, for example, 0.5 μm or more and 5 μm or less.

An infrared light cut-off function of the infrared cut-off filter13may depend on a thickness T13of the infrared cut-off filter13. The thickness T13of the infrared cut-off filter13may vary depending on the level difference among the color filters12R,12G, and12B. In view of improvement in flatness of an underlayer of the infrared cut-off filter13, the difference in the thickness T12among the color filters12R,12G, and12B is preferably smaller than the thickness T13of the infrared cut-off filter13.

The color filters12R,12G, and12B are formed by forming a coating film containing a color photosensitive resin and patterning the coating film by using a photolithography method. For example, a coating film containing a red photosensitive resin is formed by applying coating liquid containing a red photosensitive resin and drying the coating film. The red filter12R is formed by exposure and development of the coating film containing a red photosensitive resin. When the red photosensitive resin is a negative photosensitive resin, a portion of the coating film containing a red photosensitive resin, corresponding to the red filter12R, is exposed. On the other hand, when the red photosensitive resin is a positive photosensitive resin, portions of the coating film containing a red photosensitive resin, corresponding to regions other than the red filter12R, are exposed.

The color compositions for the red filter12R, the green filter12G, and the blue filter12B may include organic or inorganic pigments, and these pigments can be used singly or in combination of two or more. Pigments having high color development and high thermal stability, particularly high resistance to thermal decomposition, are preferred. Typically, organic pigments are used. Examples of the pigments include organic pigments such as phthalocyanine-based pigments, azo-based pigments, anthraquinone-based pigments, quinacridone-based pigments, dioxazine-based pigments, anthanthrone-based pigments, indanthrone-based pigments, perylene-based pigments, thioindigo-based pigments, isoindoline-based pigments, quinophthalone-based pigments, and diketopyrrolopyrrole-based pigment.

Specific examples of the organic pigments that can be used for the color composition will be described below using color index numbers.

A blue pigment used for blue color composition in the color filters may be, for example, C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64, or 81. Among these, C.I. Pigment Blue 15:6 is preferred as a blue pigment.

Further, a green color composition may be used including a green pigment and a toning pigment, instead of a blue pigment or the like. The green pigment may be, for example, C.I. Pigment Green 7, 10, 36, 37, 58, or 59. The toning pigment may be a yellow pigment described above as a toning pigment for the red color composition.

The infrared cut-off filter13cuts off infrared light that may otherwise be detected by the photoelectric conversion elements11, to prevent it from reaching the photoelectric conversion elements11, to thereby improve the accuracy of detection of visible light by the photoelectric conversion elements11. That is, the infrared cut-off filter13prevents infrared light that may otherwise be detected by the photoelectric conversion elements11, to prevent it from passing through to the photoelectric conversion elements11. The infrared light that may be detected by the photoelectric conversion elements11is near-infrared light having a wavelength of, for example, 800 nm or more and 1000 nm or less. The infrared cut-off filter13is a layer common to the red filter12R, the green filter12G, and the blue filter12B. That is, a single infrared cut-off filter13covers the red filter12R, the green filter12G, and the blue filter12B.

The transmission spectrum of the infrared cut-off filter13preferably satisfies the following conditions [A1] to [A3]. [A1] The average transmittance in the wavelength range of 450 nm or more and 650 nm or less is 80% or more.

[A2] A maximum absorption is achieved in the wavelength range of 800 nm or more and 1000 nm or less.

[A3] A cut-off wavelength width, which is a difference between the cut-off wavelength on the short-wavelength side at which the transmittance is 50% and the cut-off wavelength on the long-wavelength side at which the transmittance is 50%, is 100 nm or more.

With a configuration satisfying [A1], absorption of the visible light by the infrared cut-off filter13is sufficiently suppressed. With a configuration satisfying [A2] and [A3], the infrared cut-off filter13sufficiently cuts off the infrared light that may otherwise be detected by the respective color photoelectric conversion elements11.

A barrier function of the barrier layer14against an oxidation source may depend on the thickness of the barrier layer14. The thickness of the barrier layer14on the infrared cut-off filter13may vary depending on the level difference on the upper surface of the infrared cut-off filter13. In view of improvement in flatness of an underlayer of the barrier layer14, the thickness T13of the infrared cut-off filter13is preferably a size that provides suitable flatness to the upper surface of the infrared cut-off filter13. For suitable flatness, for example, the level difference on the upper surface of the infrared cut-off filter13is smaller than three times the thickness of the barrier layer14.

When the infrared absorbing dye described above is exposed to oxygen and water in the atmosphere in an environment irradiated with sunlight, the transmission spectrum in the near-infrared range changes. That is, when the infrared cut-off filter13is exposed to an oxidation source in an environment irradiated with sunlight, the near-infrared light cut-off performance decreases.

The barrier layer14suppresses transmission of oxygen and water, which are oxidation sources for the infrared cut-off filter13, to thereby suppress a decrease in the near-infrared light cut-off performance and a decrease in the visible light transmission performance of the infrared absorbing dye. The barrier layer14is a layer common to the red filter12R, the green filter12G, and the blue filter12B. That is, one barrier layer14covers the red filter12R, the green filter12G, and the blue filter12B.

A material constituting the barrier layer14may be an inorganic compound. The material constituting the barrier layer14is preferably a silicon compound. The material constituting the barrier layer14is, for example, at least one selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

The barrier layer14is formed by film formation using a vapor phase film formation method such as sputtering, CVD, or ion plating, or a liquid phase film formation method such as coating. For example, a barrier layer14made of a silicon oxide may be formed by film formation by sputtering using a target made of silicon oxide onto a substrate on which the infrared cut-off filter13is formed. For example, the barrier layer14made of a silicon oxide may be formed by film formation by CVD using silane and oxygen onto a substrate on which the infrared cut-off filter13is formed. For example, the barrier layer14made of a silicon oxide may be formed by applying a coating liquid containing a polysilazane, modifying, and drying the coating film.

The oxygen transmittance, thickness, and transmittance in the visible light range of the barrier layer14preferably satisfy the following condition [B1] or [B3].

[B1] The oxygen transmittance according to JIS K 7126-2:2006 is 5.0 cc/m2/day/atm or less. In other words, the oxygen transmittance is 5.0 cm3/m2/day/atm or less. The oxygen transmittance is measured in accordance with appendix A of JIS K 7126-2:2006, at 23° C. and RH 50%.

[B2] The thickness of the barrier layer14is 10 nm or more and 500 nm or less.

[B3] The transmittance in the visible light range (average) of the barrier layer14is 90% or more.

With a configuration satisfying [B1], it is possible to sufficiently prevent an oxidation source, particularly oxygen, from reaching the infrared cut-off filter13. In view of improvement in light resistance of the infrared cut-off filter13, the oxygen transmittance is preferably 3.0 cc/m2/day/atm or less, more preferably 1.0 cc/m2/day/atm or less, and still more preferably 0.7 cc/m2/day/atm or less. In other words, the oxygen transmittance is preferably 3.0 cm3/m2/day/atm or less, more preferably 1.0 cm3/m2/day/atm or less, and still more preferably 0.7 cm3/m2/day/atm or less.

With a configuration satisfying [B2], a material constituting [B1] and [B3] can be easily selected. Further, it is possible to prevent occurrence of cracking in the barrier layer14. With a configuration satisfying [B3], absorption of the visible light by the barrier layer14is sufficiently suppressed.

The barrier layer14may have a single-layer structure made of a single compound, a laminate structure composed of layers made of a single compound, or a laminate structure composed of layers made of compounds different from each other. For example, the barrier layer14may have a laminate structure composed of layers, each of which alone does not satisfy [B1], to form a configuration satisfying [B1].

As shown inFIG. 1, the color microlenses include the red microlenses15R, the green microlenses15G, and the blue microlenses15B. The red microlenses15R are disposed on a light-incident side of the red filter12R. The green microlenses15G are disposed on a light-incident side of the green filter12G. The blue microlenses15B are disposed on a light-incident side of the blue filter12B.

The color microlenses15R,15G, and15B have a light-incident surface15S which is an outer surface. In order to collect light incident on the light-incident surface15S toward the respective color photoelectric conversion elements11R,11G, and11B, the color microlenses15R,15G, and15B respectively have a refractive index different from a refractive index of the outside air by a predetermined amount.

The color microlenses15R,15G, and15B are formed by forming a coating film containing a transparent resin, patterning the coating film by using a photolithography method, and performing reflow by heat treatment. Examples of the transparent resin include acrylic resin, polyamide-based resin, polyimide-based resin, polyurethane-based resin, polyester-based resin, polyether-based resin, polyolefin-based resin, polycarbonate-based resin, polystyrene-based resin, and norbornene-based resin.

As described above, according to the first embodiment of the solid-state image sensor filter and the solid-state image sensor, the following effects can be achieved.

(1-1) Since the barrier layer14prevents an oxidation source from reaching the infrared cut-off filter13, oxidation of the infrared cut-off filter13by the oxidation source can be suppressed. Accordingly, it is possible to improve the light resistance of the infrared cut-off filter13, and thus improve the light resistance of the solid-state image sensor.

(1-2) With a configuration satisfying [B1], the effect as in the above (1-1) can be achieved. In particular, oxidation of the infrared cut-off filter13due to oxygen can be suppressed.

(1-3) When the thickness T13of the infrared cut-off filter13has a size that provides suitable flatness to the upper surface of the infrared cut-off filter13, occurrence of variation in the effect of the above (1-1) and (1-2) can be reduced.

(1-4) The larger the difference in the thickness T12among the color filters12R,12G, and12B, the larger the thickness T13for providing suitable flatness to the upper surface of the infrared cut-off filter13. Accordingly, when the difference in the thickness T12among the color filters12R,12G, and12B is smaller than the thickness T13of the infrared cut-off filter13, the thickness T13for obtaining the effect as in the above (1-3) can be reduced. Accordingly, the thickness T13of the infrared cut-off filter13can be a size specialized for cutting off the infrared light.

The above first embodiment can be modified and implemented as follows.

<First Modification>As shown inFIG. 3, the barrier layer14may not necessarily be disposed between the infrared cut-off filter13and the color microlenses15R,15G, and15B, and may be disposed on the outer surface of the color microlenses15R,15G, and15B. In this case, the outer surface of the barrier layer14functions as a light-incident surface of the solid-state image sensor on which light is incident. In short, the barrier layer14may be positioned on a light-incident side of the infrared cut-off filter13.

(1-5) According to the first modification, the barrier layer14is disposed on optical surfaces (flat surfaces) of the color microlenses15R,15G, and15B. Accordingly, the thickness of the barrier layer14can be easily made uniform, and thus the barrier function of the barrier layer14against an oxidation source can be easily made uniform.

(1-6) In the configuration of the first modification, the refractive index of the barrier layer14is preferably smaller than the refractive indices of the color microlenses15R,15G, and15B. More preferably, the difference between the refractive indices of the color microlenses15R,15G, and15B and the refractive index of the barrier layer14is 0.1 or more. With this configuration, since the difference between the refractive index of air and the refractive indices of the color microlenses can be reduced, reflected light generated on the light-incident surface can be reduced.

(1-7) The barrier layer14preferably further has an antireflection function to visible light. When the barrier layer14has an antireflection function as well, it is possible to suppress a decrease in detection sensitivity due to reflection at the light-incident surface. In addition, since the barrier layer14that reduces transmission of an oxidation source has an antireflection function, the layer structure of the solid-state image sensor filter10can be simplified compared with a configuration in which an antireflection layer is separately provided. The antireflection function may be implemented by a difference between the refractive index of the barrier layer14and the refractive indices of other layers, or may be implemented by the barrier layer14having an uneven surface formed by including a filler in the barrier layer14or by embossing barrier layer14.

<Second Modification>As shown inFIG. 4, a cut off function of the infrared cut-off filter13may be implemented by a layer other than the infrared cut-off filter13. For example, a cut off function of the infrared cut-off filter may be implemented by the color microlenses15R,15G, and15B. That is, in the solid-state image sensor filter10, a material constituting the color microlenses15R,15G, and15B can contain an infrared absorbing dye. Accordingly, the solid-state image sensor filter10can be modified to a configuration in which the infrared cut-off filter13is omitted.

(1-8) When an infrared cut-off function is implemented by the color microlenses15R,15G, and15B, the layer structure of the solid-state image sensor filter10can be simplified.

<Third Modification>As shown inFIG. 5, the color filters12R,12G, and12B tend to have thicknesses different from each other in order to convert light of different colors into approximately the same intensity. Accordingly, filters for one color tend to have a level difference from filters for other colors. In this case, the infrared cut-off filter13tends to have a shape following the level difference formed by the color filters different from each other. As described above, the shape of the infrared cut-off filter13following the level difference causes variations in thickness of the barrier layer14, and thus the barrier function of the oxidation source.

Therefore, the solid-state image sensor filter10may further include a flattening layer21between the infrared cut-off filter13and the barrier layer14. The flattening layer21has optical transmittance for transmitting visible light, and a surface of the flattening layer21has a flat surface, filling the level difference formed by the infrared cut-off filter13. That is, the flattening layer21has a shape that can reduce differences in height of the surface of the infrared cut-off filter13.

A material constituting the flattening layer21may be a transparent resin. Examples of the transparent resin include acrylic resin, polyamide-based resin, polyimide-based resin, polyurethane-based resin, polyester-based resin, polyether-based resin, polyolefin-based resin, polycarbonate-based resin, polystyrene-based resin, and norbornene-based resin. The flattening layer21is formed by film formation using a liquid phase film formation method such as coating.

(1-9) When the solid-state image sensor filter10includes the flattening layer21, it is possible to obtain the effect as in the above (1-3) and remove constraints for achieving flatness from the thickness T13of the infrared cut-off filter13and the thickness T12of the color filters12R,12G, and12B.

<Fourth Modification>As shown inFIG. 6, the solid-state image sensor filter10can include a flattening layer22between the color filters12R,12G, and12B and the infrared cut-off filter13. A material constituting the flattening layer22and a method of forming the flattening layer22may be the same as those in the third modification.

(1-10) When the solid-state image sensor filter10includes the flattening layer22, it is possible to obtain the effect as in the above (1-3) and homogenize the infrared light cut-off function of the infrared cut-off filter13.

<Fifth Modification>As shown inFIG. 7, the position of the infrared cut-off filter13is not limited to between the color filters12R,12G, and12B and the barrier layer14. The position of the infrared cut-off filter13may be modified to, for example, between the photoelectric conversion elements11and the color filters12R,12G, and12B. In short, the infrared cut-off filter13may be disposed between the barrier layer14and the photoelectric conversion elements11.

<Sixth Modification>As shown inFIG. 8, the position of the infrared cut-off filter13and the position of the barrier layer14are not limited to between the color microlenses15R,15G, and15B and the color filters12R,12G, and12B. The position of the infrared cut-off filter13and the position of the barrier layer14may be modified to between the color filters12R,12G, and12B and the photoelectric conversion elements11. In short, the infrared cut-off filter13and the barrier layer14may be disposed on a light-incident side of the photoelectric conversion elements11.

<Seventh Modification>As shown inFIG. 9, a plurality of photoelectric conversion elements11can include an infrared photoelectric conversion element11P for measuring the intensity of infrared light. In this case, the solid-state image sensor filter10includes an infrared pass filter12P on a light-incident side of the infrared photoelectric conversion element11P.

The infrared pass filter12P cuts off visible light that may otherwise be detected by the infrared photoelectric conversion element11P, to prevent it from reaching the infrared photoelectric conversion element11P, to thereby improve the accuracy of detection of infrared light by the infrared photoelectric conversion element11P. The infrared light that may be detected by the infrared photoelectric conversion element11P is near-infrared light having a wavelength of, for example, 800 nm or more and 1200 nm or less. The infrared pass filter12P is formed by forming a coating film containing a black photosensitive resin and patterning the coating film by using a photolithography method.

The infrared cut-off filter13has a through hole13H on a light-incident side of the infrared pass filter12P such that the infrared cut-off filter13is not present on a light-incident side of the infrared pass filter12P. The infrared cut-off filter13is common to the red filter12R, the green filter12G, and the blue filter12B. That is, a single infrared cut-off filter13covers the red filter12R, the green filter12G, and the blue filter12B.

The through hole13H of the infrared cut-off filter13is formed by a processing method such as patterning using photolithography or dry etching. When the through hole13H is formed by photolithography, a photosensitive composition containing an infrared absorbing dye is used as a material for constituting the infrared cut-off filter13. The photosensitive composition may contain a binder resin, a photopolymerization initiator, a polymerizable monomer, an organic solvent, a leveling agent, and the like.

The leveling agent is preferably dimethylsiloxane having a polyether structure or a polyester structure in the main chain. The dimethylsiloxane having a polyether structure in the main chain may be, for example, FZ-2122 manufactured by Toray Dow Corning Co. Ltd., BYK-333 manufactured by BYK Chemie Co., Ltd., or the like. The dimethylsiloxane having a polyester structure in the main chain may be, for example, BYK-310 or BYK-370 manufactured by BYK Chemie Co., Ltd., or the like. As the leveling agent, both the dimethylsiloxane having a polyether structure and the dimethylsiloxane having a polyester structure may be used. As the leveling agent, these may be used singly or in combination of two or more.

When the through hole13H of the infrared cut-off filter13is formed by dry etching, a curable composition containing an infrared absorbing dye is used as a material constituting the infrared cut-off filter13. The curable composition includes transparent resin. Examples of the transparent resin include acrylic resin, polyamide-based resin, polyimide-based resin, polyurethane-based resin, polyester-based resin, polyether-based resin, polyolefin-based resin, polycarbonate-based resin, polystyrene-based resin, and norbornene-based resin.

The barrier layer14has a through hole14H on a light-incident side of the infrared pass filter12P. Accordingly, the barrier layer14is not present on a light-incident side of the infrared pass filter12P. The barrier layer14is common to the red filter12R, the green filter12G, and the blue filter12B. That is, one barrier layer14covers the red filter12R, the green filter12G, and the blue filter12B.

The through hole14H of the barrier layer14may be formed by any processing method by which a hole penetrating the barrier layer14can be formed. For example, the through hole14H may be formed by dry etching.

Each of the color filters12R,12G, and12B is thinner than the infrared pass filter12P. The sum of the thickness of the infrared cut-off filter13and the thickness of the barrier layer14corresponds to a difference between the thickness of each of the color filters12R,12G, and12B and the thickness of the infrared pass filter12P.

(1-11) According to the seventh modification, light resistance of the infrared cut-off filter13can be improved, and measurement of visible light by the color photoelectric conversion elements11R,11G, and11B and measurement of infrared light by the infrared photoelectric conversion element11P are possible.

(1-12) The thickness of the infrared pass filter12P that cuts off visible light tends to be larger than the thickness of each of the color filters12R,12G, and12B. On the other hand, a level difference TP between the infrared pass filter12P and the color filters12R,12G, and12B is filled by the infrared cut-off filter13and the barrier layer14. Accordingly, even when the level difference TP is formed between the color filters12R,12G, and12B and the infrared pass filter12P, flatness of a layer underlying the microlenses15R,15G, and15B, and the infrared microlens15P can be easily obtained.

<Others>The solid-state image sensor may include an anchor layer between the barrier layer14and a layer underlying the barrier layer14. Accordingly, the anchor layer can enhance adhesion between the barrier layer14and the layer underlying the barrier layer14. Further, the solid-state image sensor may include an anchor layer between the barrier layer14and a layer overlying the barrier layer14. Accordingly, the anchor layer can enhance adhesion between the barrier layer14and the layer overlying the barrier layer14.

A material constituting the anchor layer may be, for example, a polyfunctional acrylic resin or a silane coupling agent. The film thickness of the anchor layer may be, for example, 50 nm or more and 1 μm or less. When the anchor layer has a thickness of 50 nm or more, adhesion between layers can be easily obtained. When the anchor layer has a thickness of 1 μm or less, absorption of light by the anchor layer can be easily suppressed.A plurality of photoelectric conversion elements11may be composed of an organic photoelectric conversion element and an inorganic photoelectric conversion element. With this configuration, the color filters12R,12G, and12B can be omitted. Even when the color filters12R,12G, and12B are omitted, it is possible to protect the cut off function of the infrared cut-off filter13by the solid-state image sensor filter10having the infrared cut-off filter13and the above-mentioned barrier function.The solid-state image sensor filter10may include a black matrix and a flattening layer between the plurality of photoelectric conversion elements11and the color filters12R,12G, and12B. The black matrix prevents light of each color selected by the corresponding color filters12R,12G, and12B from entering the photoelectric conversion elements11for other colors. The flattening layer fills the level difference in the black matrix to thereby flatten the underlayer of the color filters12R,12G, and12B, and the underlayer of the infrared cut-off filter13. Accordingly, the flattening layer flattens the underlayer of the barrier layer14.The color filters may be modified to those for three colors composed of a cyan filter, a yellow filter, and a magenta filter. Further, the color filters may be modified to those for four colors composed of a cyan filter, a yellow filter, a magenta filter, and a black filter. Further, the color filters may be modified to those for four colors composed of a transparent filter, a yellow filter, a red filter, and a black filter.The color filters12R,12G, and12B have a refractive index of, for example, 1.6 or more and 1.9 or less. The microlenses15R,15G, and15B have a refractive index of, for example, 1.4 or more and 2.0 or less. More preferably, the microlenses15R,15G, and15B have a refractive index of 1.5 or more and 1.7 or less. Materials constituting the infrared cut-off filter13and the infrared pass filter12P can contain particles of inorganic oxide in order to reduce a difference between refractive indices of the respective color filters12R,12G, and12B and the respective microlenses15R,15G, and15B. Examples of the inorganic oxide include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide.Materials constituting the infrared cut-off filter13and the infrared pass filter12P can contain additives such as a photostabilizer, an antioxidant, a thermal stabilizer, and antistatic agent in order to provide other functions.The solid-state image sensor can be modified to a configuration in which the barrier layer14is omitted and a laminate structure located on a side of the infrared cut-off filter13on which the light-incident surface15S is disposed has an oxygen transmittance of 5.0 cc/m2/day/atm or less. For example, the laminate structure may include the color filters12R,12G, and12B, the flattening layer, and the color microlenses15R,15G, and15B, and have an oxygen transmittance of 5.0 cc/m2/day/atm or less.

Second Embodiment

With reference toFIGS. 10 to 12, a second embodiment of the solid-state image sensor will be described.FIG. 10is a schematic configuration diagram in which layers in part of a solid-state image sensor are separately illustrated.

As shown inFIG. 10, the solid-state image sensor includes a solid-state image sensor filter10and a plurality of photoelectric conversion elements11. The solid-state image sensor filter10includes color filters12R,12G, and12B, an infrared pass filter12P, a barrier layer14, and microlenses15R,15G,15B, and15P. The infrared pass filter12P is an example of an infrared filter.

The color filters12R,12G, and12B are disposed between photoelectric conversion elements11R,11G, and11B for three colors and the microlenses15R,15G, and15B, respectively. The infrared pass filter12P is disposed between an infrared photoelectric conversion element11P and the microlens15P. The barrier layer14is disposed between the infrared pass filter12P and the infrared microlens15P. The barrier layer14is disposed on a light-incident side of the infrared pass filter12P.

The photoelectric conversion elements11for three colors are examples of the first photoelectric conversion element, and composed of the red photoelectric conversion element11R, the green photoelectric conversion element11G, and the blue photoelectric conversion element11B. The infrared photoelectric conversion element11P is an example of the second photoelectric conversion element. The solid-state image sensor includes a plurality of red photoelectric conversion elements11R, a plurality of green photoelectric conversion elements11G, a plurality of blue photoelectric conversion elements11B, and a plurality of infrared photoelectric conversion elements11P.FIG. 10illustrates one repeating unit of the photoelectric conversion elements11in the solid-state image sensor.

As shown inFIG. 11, the color filters12R,12G, and12B have thicknesses T12which may be different from that of the infrared pass filter12P, or may be the same as that of the infrared pass filter12P. The thickness T12of the color filters12R,12G, and12B is, for example, 0.5 μm or more and 5 μm or less.

A function of the infrared pass filter12P of transmitting infrared light may depend on a thickness T12of the infrared pass filter12P. The processing accuracy of the microlenses15R,15G, and15B disposed on the color filters12R,12G, and12B, respectively, and the microlens15P disposed on the barrier layer14may be reduced due to a level difference between the color filters12R,12G, and12B and the barrier layer14. Therefore, in view of improvement in flatness of an underlayer of the microlenses15R,15G,15B, and15P, the sum of the thickness T12of the infrared pass filter12P and the thickness T14of the barrier layer14is preferably substantially equal to the thickness of each of the color filters12R,12G, and12B.

The infrared pass filter12P cuts off visible light that may otherwise be detected by the infrared photoelectric conversion element11P, to prevent it from reaching the infrared photoelectric conversion element11P, to thereby improve the accuracy of detection of near-infrared light by the infrared photoelectric conversion element11P. That is, the infrared pass filter12P prevents the visible light that may be detected by the infrared photoelectric conversion element11P from passing through to the infrared photoelectric conversion element11P. The infrared pass filter12P is a layer disposed only on the infrared photoelectric conversion element11P.

Materials constituting the infrared pass filter12P include a black colorant or a black dye, and a transparent resin. The black colorant may be a single colorant having a black color, or a mixture of two or more colorants having a black color. Examples of the black dye include azo-based dye, anthraquinone-based dye, azine-based dye, quinoline-based dye, perinone-based dye, perylene-based dye, and methine-based dye. Examples of the transparent resin include acrylic resin, polyamide-based resin, polyimide-based resin, polyurethane-based resin, polyester-based resin, polyether-based resin, polyolefin-based resin, polycarbonate-based resin, polystyrene-based resin, and norbornene-based resin. The infrared pass filter12P is formed by film formation using a liquid phase film formation method such as coating.

A material constituting the infrared pass filter12P can contain particles of inorganic oxide in order to adjust the refractive index of the infrared pass filter12P. Examples of the inorganic oxide include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide. The infrared pass filter12P can contain additives such as a photostabilizer, an antioxidant, a thermal stabilizer, and antistatic agent in order to provide other functions.

As shown inFIG. 12, the transmission spectrum of the infrared pass filter12P shows, for example, a transmittance of 3% or less in the wavelength range of 400 nm or more and 700 nm or less. On the other hand, the infrared pass filter12P has a transmittance of 10% or more at the wavelength of 850 nm as a peak, and a transmittance of 90% or more at the wavelength of 900 nm or more.

The solar spectrum has absorption bands due to absorption by water vapor at wavelengths around 940 nm. Accordingly, the spectral intensity in the solar spectrum decreases at wavelengths around 940 nm. Therefore, when the solid-state image sensor is used outdoors in the day time, near-infrared light having the wavelength of 940 nm is not likely to be affected by sunlight, which is ambient light. That is, when the center wavelength of a light source that is used is 940 nm, a solid-state image sensor with less noise can be provided. The infrared photoelectric conversion element11P detects near-infrared light having a wavelength of 940 nm.

The barrier layer14suppresses transmission of oxygen and water, which are oxidation sources to the infrared pass filter12P, to thereby suppress a decrease in the visible light cut-off performance and a decrease in the near-infrared light transmission performance of the black colorant and black dye. The barrier layer14is located on a side of the infrared pass filter12P on which the light-incident surface15S is disposed, and is not located on a side of the color filters12R,12G, and12B on which the light-incident surface15S is disposed. That is, the barrier layer14covers the infrared pass filter12P, but does not cover the color filters12R,12G, and12B.

As with the barrier layer14of the first embodiment, the oxygen transmittance, thickness, and transmittance in the visible light range of the barrier layer14preferably satisfy the above condition [B1] or [B3].

With a configuration satisfying [B1], it is possible to sufficiently prevent an oxidation source, particularly oxygen, from reaching the infrared pass filter12P. In view of improvement in light resistance of the infrared cut-off filter13, the oxygen transmittance is preferably 3.0 cc/m2/day/atm or less, more preferably 1.0 cc/m2/day/atm or less, and still more preferably 0.7 cc/m2/day/atm or less.

With a configuration satisfying [B2], a material constituting [B1] and [B3] can be easily selected. Further, it is also possible to prevent occurrence of cracking in the barrier layer14. With a configuration satisfying [B3], absorption of the visible light by the barrier layer14is sufficiently suppressed.

As described above, according to the second embodiment of the solid-state image sensor filter and the solid-state image sensor, the following effects can be achieved.

(2-1) Since the barrier layer14prevents an oxidation source from reaching the infrared pass filter12P, oxidation of the infrared pass filter12P by the oxidation source can be suppressed. Accordingly, it is possible to improve the light resistance of the infrared pass filter12P, and thus improve the light resistance of the solid-state image sensor.

(2-2) With a configuration satisfying [B1], the effect as in the above (2-1) can also be achieved. In particular, oxidation of the infrared pass filter12P due to oxygen can be suppressed.

(2-3) When the sum of the thickness T12of the infrared pass filter12P and the thickness T14of the barrier layer14is substantially the same as the thickness of each of the color filters12R,12G, and12B, the underlayer of the microlenses15R,15G,15B, and15P can have high flatness. Accordingly, it is also possible to prevent occurrence of variation in processing and shape of the microlenses15R,15G,15B, and15P.

The above second embodiment can be modified and implemented as follows.

As shown inFIG. 13, the barrier layer14may be disposed on a light-incident side of the infrared pass filter12P and the color filters12R,12G, and12B. That is, the barrier layer14may be disposed on a side of all of the photoelectric conversion elements11facing the light-incident surface15S.

(2-4) When the barrier layer14is configured to be located on a side of all of the photoelectric conversion elements11facing the light-incident surface15S, the barrier layer14can be formed by using a method of forming the barrier layer14on the entirety of a layer where the film is to be formed. Since a separate step of removing the barrier layer14from the color filters12R,12G, and12B is not necessary, the method of forming the solid-state image sensor can be simplified.

(2-5) Since the light-incident surface15S-side of the color filters12R,12G, and12B adjacent to the infrared pass filter12P is covered by the barrier layer14, oxidation of the infrared pass filter12P can be further effectively reduced.

As shown inFIG. 14, the infrared pass filter12P that cuts off all the wavelength bands of visible light tends to have a thickness different from that of the respective color filters12R,12G, and12B. Accordingly, the infrared pass filter12P tends to form a level difference between the infrared pass filter12P and the respective color filters12R,12G, and12B. In this case, the top and part of the peripheral surface of the infrared pass filter12P are exposed from the respective color filters12R,12G, and12B.

As in the first modification, when the barrier layer14is located on a side of all of the photoelectric conversion elements11facing the light-incident surface15S, the barrier layer14tends to have a shape following the level difference formed between the infrared pass filter12P and the color filters12R,12G, and12B. The shape of the barrier layer14following the level difference causes variations in thickness of the barrier layer14, and thus the barrier function of the oxidation source. In particular, a barrier function against the oxidation source may decrease in part of the peripheral surface of the infrared pass filter12P.

Therefore, a flattening layer23may be further provided between the infrared pass filter12P, the color filters12R,12G, and12B, and the barrier layer14. The flattening layer23has optical transmittance for transmitting visible light, and a surface of the flattening layer23has a flat surface, filling the level difference formed by the infrared pass filter12P. That is, the flattening layer23has a shape that can reduce the difference in height formed by the infrared pass filter12P and the color filters12R,12G, and12B.

A material constituting the flattening layer23may be a material that can be used for the flattening layer21of the first embodiment.

(2-6) When the flattening layer23is further provided, the effect as in the above (2-1) and (2-5) can be obtained even when part of the peripheral surface of the infrared pass filter12P is exposed from the color filters12R,12G, and12B.

As shown inFIG. 15, the solid-state image sensor further includes an infrared cut-off filter13. The infrared cut-off filter13cuts off the infrared light that may otherwise be detected by the respective color photoelectric conversion elements11R,11G, and11B, to thereby improve the accuracy of detection of visible light by the photoelectric conversion elements11. The infrared light that may be detected by the photoelectric conversion elements11is near-infrared light having a wavelength of, for example, 800 nm or more and 1000 nm or less. The infrared cut-off filter13is a layer common to the red filter12R, the green filter12G, and the blue filter12B. That is, a single infrared cut-off filter13covers the red filter12R, the green filter12G, and the blue filter12B.

The infrared cut-off filter13is disposed on a light-incident side of the color filters12R,12G, and12B. The infrared cut-off filter13has a through hole13H on a light-incident side of the infrared pass filter12P such that the infrared cut-off filter13is not present on a light-incident side of the infrared pass filter12P.

An infrared light cut-off function of the infrared cut-off filter13may depend on a thickness of the infrared cut-off filter13. The thickness of the infrared cut-off filter13may vary depending on the level difference among the color filters12R,12G, and12B at positions on the color filters12R,12G, and12B, and between the color filters12R,12G, and12B. In view of improvement in flatness of an underlayer of the infrared cut-off filter13, the difference in the thickness among the color filters12R,12G, and12B is preferably smaller than the thickness of the infrared cut-off filter13.

As shown inFIG. 16, each of the color filters12R,12G, and12B is thinner than the infrared pass filter12P. In this case, the infrared cut-off filter13preferably has a thickness corresponding to the difference in film thickness between each of the color filters12R,12G, and12B and the infrared pass filter12P.

In the example shown inFIG. 16, a surface of the infrared pass filter12P on a side on which the light-incident surface is disposed and a surface of the infrared cut-off filter13on a side on which the light-incident surface is disposed are located at the same height. That is, a surface of the infrared pass filter12P in contact with the barrier layer14and a surface of the infrared cut-off filter13in contact with the barrier layer14are located at the same height. In other words, a surface of the infrared pass filter12P on a side on which the light-incident surface is disposed and a surface of the infrared cut-off filter13on a side on which the light-incident surface is disposed are flush with each other.

The transmission spectrum of the infrared cut-off filter13preferably satisfies the above conditions [A1] to [A3].

With a configuration satisfying [A1], absorption of the visible light by the infrared cut-off filter13is sufficiently suppressed. With a configuration satisfying [A2] and [A3], the infrared cut-off filter13sufficiently cuts off infrared light that may otherwise be detected by the respective color photoelectric conversion elements11, and prevents visible light from being cut off.

(2-7) When the infrared absorbing dye is exposed to oxygen and water in the atmosphere in an environment irradiated with sunlight, the transmission spectrum in the near-infrared range changes. That is, when the infrared cut-off filter13is exposed to an oxidation source in an environment irradiated with sunlight, the near-infrared light cut-off performance decreases. In this regard, since the barrier layer14is located on a side of the infrared cut-off filter13on which the light-incident surface15S is disposed, it is possible to enhance light resistance of the infrared cut-off filter13.

(2-8) Since the light resistance of the infrared pass filter12P and the light resistance of the infrared cut-off filter13are increased by a single barrier layer14, a layer configuration of the solid-state image sensor can be simplified compared with a configuration having separate barrier layers.

(2-9) When the sum of the thickness of the infrared cut-off filter13and the thickness of each of the color filters12R,12G, and12B corresponds to the thickness of the infrared pass filter12P, it is possible to provide suitable flatness to the underside of the barrier layer14. Accordingly, occurrence of variation in the effect of the above (2-1) and (2-7) can be reduced.

<Others>The barrier layer14may not necessarily be disposed between the infrared pass filter12P and the infrared microlens15P, and may be disposed on the outer surface of the infrared microlens15P. In this case, the outer surface of the barrier layer14functions as a light-incident surface of the solid-state image sensor on which light is incident. In short, the barrier layer14may be positioned on a light-incident side of the infrared pass filter12P. With this configuration, the barrier layer14is disposed on an optical surface (flat surface) of the infrared microlens15P. Accordingly, the thickness of the barrier layer14can be easily made uniform, and thus the barrier function of the barrier layer14against an oxidation source can be easily made uniform.The solid-state image sensor may include an anchor layer between the barrier layer14and a layer underlying the barrier layer14. Accordingly, the anchor layer can enhance adhesion between the barrier layer14and the layer underlying the barrier layer14. Further, the solid-state image sensor may include an anchor layer between the barrier layer14and a layer overlying the barrier layer14. Accordingly, the anchor layer can enhance adhesion between the barrier layer14and the layer overlying the barrier layer14.

A material constituting the anchor layer and a thickness of the anchor layer may be the same as those in the modifications of the first embodiment.A plurality of photoelectric conversion elements11may be composed of an organic photoelectric conversion element and an inorganic photoelectric conversion element, and the color filters12R,12G, and12B may be omitted from the solid-state image sensor filter10. Even when the color filters12R,12G, and12B are omitted, it is possible to protect the transmission function of the infrared pass filter12P by the above-mentioned barrier function when the infrared pass filter12P is provided.The solid-state image sensor filter10may include a black matrix and a flattening layer between the plurality of photoelectric conversion elements11and the color filters12R,12G,12B, and the infrared pass filter12P. The black matrix prevents light of each color selected by the corresponding color filters12R,12G, and12B from entering the photoelectric conversion elements11for other colors. The flattening layer fills the level difference in the black matrix to thereby flatten the underlayer of the color filters12R,12G, and12B, the underlayer of the infrared pass filter12P, and the underlayer of the infrared cut-off filter13. Accordingly, the flattening layer flattens the underlayer of the barrier layer14.The color filters may be modified to those for three colors composed of a cyan filter, a yellow filter, and a magenta filter. Further, the color filters may be modified to those for four colors composed of a cyan filter, a yellow filter, a magenta filter, and a black filter. Further, the color filters may be modified to those for four colors composed of a transparent filter, a yellow filter, a red filter, and a black filter.The color filters12R,12G, and12B have a refractive index of, for example, 1.7 or more and 1.9 or less. The microlenses15R,15G, and15B have a refractive index of, for example, 1.5 or more and 1.6 or less. Materials constituting the infrared pass filter12P and the infrared cut-off filter13can contain particles of inorganic oxide in order to reduce a difference between refractive indices of the respective color filters12R,12G, and12B and the respective microlenses15R,15G, and15B. Examples of the inorganic oxide include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide.Materials constituting the infrared pass filter12P and the infrared cut-off filter13can contain additives such as a photostabilizer, an antioxidant, a thermal stabilizer, and an antistatic agent in order to provide other functions.The solid-state image sensor can be modified to a configuration in which the barrier layer14is omitted and a laminate structure located on a side of the infrared pass filter12P on which the light-incident surface15S is disposed has an oxygen transmittance of 5.0 cc/m2/day/atm or less. For example, the laminate structure is formed by other functional layers such as a flattening layer, an adhesion layer, and the like. The laminate structure together with the infrared microlens15P may form a structure having an oxygen transmittance of 5.0 cc/m2/day/atm or less.The solid-state image sensor may further include a band-pass filter on a light-incident side of the plurality of microlenses. The band-pass filter is a filter that transmits specific wavelengths of visible light and near-infrared light, and has a function similar to that of the infrared cut-off filter13. That is, the band-pass filter can cut off unnecessary infrared light which may otherwise be detected by the respective color photoelectric conversion elements11R,11G,11B, and the infrared photoelectric conversion element11P. Accordingly, it is possible to improve the accuracy of detection of the visible light by the respective color photoelectric conversion elements11R,11G, and11B, and detection of the near-infrared light in the 850 nm or 940 nm wavelength band by the infrared photoelectric conversion element11P.

The present application addresses the following. Materials constituting an infrared filter including an infrared cut-off filter and an infrared pass filter tend not to have high light resistance compared with materials constituting a photoelectric conversion element and the like. On the other hand, with the development of image processing and sensing, the application range of solid-state image sensors is steadily expanding. A technique for improving the light resistance of infrared filters and, by extension, the light resistance of solid-state image sensors is being sought, with increasing demand for expanding the range of application of solid-state image sensors.

An aspect of the present invention is to provide a solid-state image sensor filter and a solid-state image sensor capable of improving light resistance of the solid-state image sensor.

A solid-state image sensor filter includes: a light-incident surface on which light is incident; an infrared filter located on a side of a photoelectric conversion element on which the light-incident surface is disposed, the infrared filter being provided to suppress transmission of infrared light; and a barrier layer located on a side of the infrared filter on which the light-incident surface is disposed, the barrier layer being provided to suppress transmission of an oxidation source to thereby prevent the infrared filter from being oxidized.

A solid-state image sensor filter includes: a light-incident surface on which light is incident; and an infrared filter located on a side of a photoelectric conversion element on which the light-incident surface is disposed, the infrared filter being provided to suppress transmission of infrared light, wherein a laminate structure located on a side of the infrared filter on which the light-incident surface is disposed has an oxygen transmittance of 5.0 cc/m2/day/atm or less.

According to the above configurations, since an oxidation source is prevented from reaching the infrared filter, oxidation of the infrared filter by the oxidation source is suppressed. Accordingly, it is possible to improve the light resistance of the infrared filter, and thus improve the light resistance of the solid-state image sensor.

In the above solid-state image sensor filter, the infrared filter may be an infrared cut-off filter, and the infrared cut-off filter may be an array of microlenses containing an infrared absorber. With this configuration, since the microlenses having a function of collecting light toward the photoelectric conversion element further also have an infrared light cut-off function, the layer structure of the solid-state image sensor filter can be simplified.

In the above solid-state image sensor filter, the barrier layer may have a refractive index smaller than a refractive index of the microlenses. The refractive index of the microlenses containing an infrared absorber is larger than the refractive index of the microlenses that do not contain an infrared absorber, and light reflection at the surface of the microlenses increases. In this regard, according to the above configuration, in which the barrier layer has a refractive index smaller than a refractive index of the microlens layer containing an infrared absorber, light reflection at the surface of the microlenses can be reduced.

In the above solid-state image sensor filter, the barrier layer may have an antireflection function. With this configuration, the antireflection function can suppress a decrease in detection sensitivity due to reflection at the surface of the microlenses. In addition, since the barrier layer that reduces transmission of an oxidation source further has an antireflection function, the layer structure of the solid-state image sensor filter can also be simplified.

The above solid-state image sensor filter may include a color filter located on a side of the photoelectric conversion element on which the light-incident surface is disposed. With this configuration, the photoelectric conversion element may have a configuration common for all colors.

The above solid-state image sensor filter may include an infrared pass filter located on a side of the photoelectric conversion element on which the light-incident surface is disposed; and the infrared cut-off filter may have a through hole on a light-incident side of the infrared pass filter. With this configuration, light resistance of the infrared cut-off filter can be improved, and measurement of visible light and measurement of infrared light by an infrared photoelectric conversion element are possible.

In the above solid-state image sensor filter, the infrared filter may be an infrared pass filter, the photoelectric conversion element may be a first photoelectric conversion element, the solid-state image sensor filter may further include: a color filter located on a side of a second photoelectric conversion element on which the light-incident surface is disposed; and an infrared cut-off filter located on a side of the second photoelectric conversion element on which the light-incident surface is disposed, and the barrier layer may be located on a side of the infrared cut-off filter on which the light-incident surface is disposed.

With this configuration, light resistance of the infrared pass filter and light resistance of the infrared cut-off filter can be improved by a common barrier layer. Accordingly, light resistance of a multi-functional solid-state image sensor having an infrared light detection function and a visible light detection function can be improved with a simple configuration.

In the solid-state image sensor filter, a surface of the infrared pass filter on a side on which the light-incident surface is disposed and a surface of the infrared cut-off filter on a side on which the light-incident surface is disposed may be located at the same height.

With this configuration, the infrared pass filter and the infrared cut-off filter, which are layers underlying the barrier layer, are positioned at the same height. Accordingly, it is possible to decrease a level difference of an underlayer of the barrier layer. Compared with a configuration in which the barrier layer is disposed on an underlayer having a large level difference, the variation in thickness and composition of the barrier layer can be reduced, and the barrier layer can easily perform a transmission suppression function across the entire underlayer.

In the above solid-state image sensor filter, the barrier layer may have an oxygen transmittance of 5.0 cc/m2/day/atm or less. With this configuration, since the oxygen transmittance of the barrier layer is set to 5.0 cc/m2/day/atm or less, oxidation of the infrared cut-off filter by oxygen can be suppressed.

The above solid-state image sensor filter may further include a flattening layer that fills a level difference of an underlayer of the flattening layer, wherein the barrier layer may be located on a side of the flattening layer on which the light-incident surface is disposed.

With this configuration, since the barrier layer is located on a side of the flattening layer on which the light-incident surface is disposed, it is possible to decrease a level difference of the underlayer of the barrier layer. Compared with a configuration in which the barrier layer is disposed on an underlayer having a large level difference, the variation in thickness and composition of the barrier layer can be reduced, and the barrier layer can easily perform a transmission suppression function across the entire underlayer.

A solid-state image sensor for solving the above problem includes: a photoelectric conversion element; and the solid-state image sensor filter described above.

According to embodiments of the present invention, light resistance of a solid-state image sensor can be improved.

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