Solid-state imaging device and solid-state imaging device filter

Abstract

An optical sensor includes an incident surface for light incidence, an infrared filter located on the incident surface side with respect to a photoelectric conversion element, and a barrier layer located on the incident surface side with respect to the infrared filter, which suppresses the transmission of an oxidation source that oxidizes the infrared filter.

Description

[0001] This application is based on the Chinese National Application No. filed on January 27, 2020.

[0002] The following is a divisional application of application 2020800071157 (PCT / JP2020 / 002764) (Filter for Solid State Imaging Element and Solid State Imaging Element), the contents of which are quoted below. Technical Field

[0003] This invention relates to filters for solid-state imaging elements, and solid-state imaging elements having filters for solid-state imaging elements. Background Technology

[0004] Solid-state imaging elements, such as CMOS image sensors and CCD image sensors, incorporate photoelectric conversion elements that convert light intensity into electrical signals. A first example of a solid-state imaging element includes color filters for various colors and photoelectric conversion elements, detecting light of various colors using these photoelectric conversion elements (see, for example, Patent Document 1). A second example of a solid-state imaging element incorporates both organic and inorganic photoelectric conversion elements, detecting light of various colors using individual photoelectric conversion elements instead of color filters (see, for example, Patent Document 2).

[0005] Not only in the visible light band, but also in the infrared light band, including near-infrared light, the photoelectric conversion element has an absorption band. The third example of a solid-state imaging element has an infrared cutoff filter on the photoelectric conversion element, which blocks the infrared light detectable by each photoelectric conversion element relative to the photoelectric conversion element, thereby improving the detection accuracy of each photoelectric conversion element for visible light. The constituent materials of the infrared cutoff filter are, for example, anthraquinone compounds, phthalocyanine compounds, anthocyanin compounds, imine compounds, and diimine compounds (see, for example, Patent Documents 1, 3, and 4).

[0006] Furthermore, the fourth example of a solid-state imaging element includes an infrared bandpass filter on the infrared photoelectric conversion element, which blocks visible light that can be detected by the infrared photoelectric conversion element, thereby improving the detection accuracy of infrared light by the infrared photoelectric conversion element. The infrared bandpass filter is made of black materials such as bisbenzofuranone pigments, azomethyl alkali pigments, perylene pigments, and azo dyes (see, for example, Patent Documents 5 and 6).

[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-060176

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-060910

[0009] Patent Document 3: Japanese Patent Application Publication No. 2017-181705

[0010] Patent Document 4: Japanese Patent Application Publication No. 2018-120097

[0011] Patent Document 5: Japanese Patent Application Publication No. 2016-177273

[0012] Patent Document 6: Japanese Patent Application Publication No. 2018-119077 Summary of the Invention

[0013] On the other hand, it is difficult to assert that the materials used in infrared filters, including infrared cut-off filters and infrared bandpass filters, have higher lightfastness compared to the materials used in photoelectric conversion elements. Furthermore, the application range of solid-state imaging devices is expanding with the development of image processing and sensing technologies. As the demand for expanding the application range of solid-state imaging devices increases, there is a stronger need for technologies that can improve the lightfastness of infrared filters, and consequently, the lightfastness of solid-state imaging devices.

[0014] The purpose of this invention is to provide a filter for a solid-state imaging element and a solid-state imaging element that can improve the light resistance of the solid-state imaging element.

[0015] A filter for a solid-state imaging element used to solve the above problems has: an incident surface for light incidence; an infrared filter located on the incident surface side relative to a photoelectric conversion element to suppress the transmission of infrared light; and a barrier layer located on the incident surface side relative to the infrared filter to suppress the transmission of an oxidation source that causes the infrared filter to oxidize.

[0016] A filter for a solid-state imaging element used to solve the above problems has: an incident surface for light incidence; and an infrared filter located on the incident surface side relative to the photoelectric conversion element to suppress the transmission of infrared light. The oxygen transmittance of the stacked structure located on the incident surface side relative to the infrared filter is less than or equal to 5.0 cc / m 2 / day / atm.

[0017] Based on the above structures, the arrival of oxidation sources at the infrared filter is suppressed, thus making the infrared filter less susceptible to oxidation. As a result, the lightfastness of the infrared filter and consequently the lightfastness of the solid-state imaging element can be improved.

[0018] In the aforementioned filter for a solid-state imaging element, the infrared filter can be an infrared cut-off filter, which can be a microlens containing an infrared absorber. According to this structure, the microlens, which has the function of guiding light toward the photoelectric conversion element, also has an infrared light cut-off function, thus simplifying the layered structure of the filter for the solid-state imaging element.

[0019] In the aforementioned filter for a solid-state imaging element, the refractive index of the barrier layer can be lower than that of the microlens. Microlenses containing infrared absorbers have a higher refractive index than those without, increasing the light reflection from the microlens surface. Therefore, based on the above structure, a barrier layer with a refractive index lower than that of the microlens layer containing infrared absorbers is formed, thereby suppressing light reflection from the microlens surface.

[0020] In the aforementioned filter for a solid-state imaging element, the barrier layer can have an anti-reflective function. According to this structure, the decrease in detection sensitivity caused by reflection from the surface of the microlens can be suppressed through the anti-reflective function. Furthermore, the barrier layer, which suppresses the transmission of the oxide source, also has an anti-reflective function, thus simplifying the layer structure of the filter for the solid-state imaging element.

[0021] The aforementioned filter for a solid-state imaging element can have a color filter located on the incident surface side relative to the photoelectric conversion element. According to this structure, the structure can be generalized for photoelectric conversion elements used for various colors.

[0022] The aforementioned filter for a solid-state imaging element may have an infrared bandpass filter located on the incident surface side relative to the photoelectric conversion element, and the infrared cutoff filter may have a through-hole on the light incident side relative to the infrared bandpass filter. According to this structure, the lightfastness of the infrared cutoff filter can be improved, and it is also possible to measure visible light and to measure infrared light using an infrared photoelectric conversion element.

[0023] In the above-mentioned filter for a solid-state imaging element, the infrared filter may be an infrared bandpass filter, the photoelectric conversion element is a first photoelectric conversion element, and the filter for a solid-state imaging element further comprises: a color filter located on the incident surface side relative to the second photoelectric conversion element; and an infrared cut-off filter located on the incident surface side relative to the second photoelectric conversion element, and the blocking layer located on the incident surface side relative to the infrared cut-off filter.

[0024] Based on the above structure, the light resistance of both infrared bandpass filters and infrared cutoff filters can be improved through a universal barrier layer. As a result, the light resistance of a multifunctional solid-state imaging element with both infrared and visible light detection capabilities can be improved with a simple structure.

[0025] In the above-mentioned filters for solid-state imaging elements, the incident surface side of the infrared bandpass filter and the incident surface side of the infrared cutoff filter can be located at the same height.

[0026] According to the above structure, the infrared bandpass filter and the infrared cutoff filter, which serve as the lower layer of the barrier layer, are located at the same height. Therefore, the step difference of the barrier layer substrate can be reduced, and compared with the structure in which the barrier layer is located above a substrate with a large step difference, it is easier to suppress fluctuations in the thickness and composition of the barrier layer, and it is easier to exert the transmission suppression function of the barrier layer throughout the entire substrate.

[0027] In the aforementioned filter for solid-state imaging elements, the oxygen permeability of the barrier layer can be less than or equal to 5.0 cc / m 2 / day / atm. Based on this structure, the oxygen permeability of the barrier layer is specified to be less than or equal to 5.0cc / m². 2 / day / atm, therefore the infrared cut-off filter is not easily oxidized by oxygen.

[0028] In the above-mentioned solid-state imaging element filter, there may also be a planarization layer that fills the step difference of the base layer of the planarization layer, and the barrier layer may be located on the incident surface side of the light relative to the planarization layer.

[0029] According to the above structure, the barrier layer is located on the incident surface side of the planarization layer, thus reducing the step difference of the barrier layer substrate. Moreover, compared with the structure in which the barrier layer is located above the substrate with a large step difference, it is easier to suppress fluctuations in the thickness and composition of the barrier layer, and it is easier to exert the transmission suppression function of the barrier layer throughout the entire substrate.

[0030] Solid-state imaging elements for solving the above problems include photoelectric conversion elements and filters for the solid-state imaging elements.

[0031] The effects of the invention

[0032] According to the present invention, the lightfastness of solid-state imaging elements can be improved. Attached Figure Description

[0033] Figure 1 This is an exploded perspective view showing a portion of the layer structure of the first embodiment of the solid-state imaging element.

[0034] Figure 2 yes Figure 1 Sectional view along line II-II.

[0035] Figure 3 This is a cross-sectional view showing the layer structure of a first modified example of the solid-state imaging element according to the first embodiment.

[0036] Figure 4 This is a cross-sectional view showing the layer structure of a second modified example of the solid-state imaging element according to the first embodiment.

[0037] Figure 5This is a cross-sectional view showing the layer structure of a third modified example of the solid-state imaging element according to the first embodiment.

[0038] Figure 6 This is a cross-sectional view showing the layer structure of a fourth modified example of the solid-state imaging element according to the first embodiment.

[0039] Figure 7 This is a cross-sectional view showing the layer structure of a fifth modified example of the solid-state imaging element according to the first embodiment.

[0040] Figure 8 This is a cross-sectional view showing the layer structure of a sixth modified example of the solid-state imaging element according to the first embodiment.

[0041] Figure 9 This is an exploded perspective view showing a portion of the layer structure of a seventh variation of the solid-state imaging element according to the first embodiment.

[0042] Figure 10 This is an exploded perspective view showing a portion of the layer structure of the second embodiment of the solid-state imaging element.

[0043] Figure 11 yes Figure 10 XI-XI profile.

[0044] Figure 12 This is a graph representing an example of the transmission spectrum of an infrared bandpass filter.

[0045] Figure 13 This is an exploded perspective view showing a portion of the layer structure of a first modified example of the solid-state imaging element according to the second embodiment.

[0046] Figure 14 This is a cross-sectional view showing the layer structure of a second modified example of the solid-state imaging element according to the second embodiment.

[0047] Figure 15 This is an exploded perspective view showing a portion of the layer structure of a third modified example of the solid-state imaging element according to the second embodiment.

[0048] Figure 16 yes Figure 15 XVI-XVI line cross-section. Detailed Implementation

[0049] [First Implementation]

[0050] Below, refer to Figure 1 and Figure 2 A first embodiment of a filter for a solid-state imaging element and a solid-state imaging element will be described. Figure 1 This is a schematic structural diagram showing the layers of a portion of a solid-state imaging element. Among them, Figure 1 and Figure 2 The structures shown are all examples of solid-state imaging element structures. For example... Figure 1 As shown, the gap can be located between the filters for various colors on the solid-state imaging element, such as... Figure 2 As shown, the gap may not be located between filters used for various colors.

[0051] like Figure 1 As shown, the solid-state imaging element includes a solid-state imaging element filter 10 and a plurality of photoelectric conversion elements 11. The solid-state imaging element filter 10 includes filters 12R, 12G, and 12B for various colors, an infrared cut-off filter 13 as an example of an infrared filter, a blocking layer 14, and microlenses 15R, 15G, and 15B for various colors.

[0052] Color filters 12R, 12G, and 12B are located between the photoelectric conversion element 11 for the three colors and the infrared cut-off filter 13. A barrier layer 14 is located between the infrared cut-off filter 13 and the microlenses 15R, 15G, and 15B for the various colors. The infrared cut-off filter 13 is located on the light incident side relative to the color filters 12R, 12G, and 12B. The barrier layer 14 is located on the light incident side relative to the infrared cut-off filter 13.

[0053] The three-color photoelectric conversion element 11 is composed of a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, and a blue photoelectric conversion element 11B. The solid-state imaging element has multiple red photoelectric conversion elements 11R, multiple green photoelectric conversion elements 11G, and multiple blue photoelectric conversion elements 11B. Figure 1 The image shows a repeating unit of the photoelectric conversion element 11 of the solid-state imaging element.

[0054] The three-color filter consists of a red filter 12R, a green filter 12G, and a blue filter 12B. The red filter 12R is located on the incident side of light relative to the red photoelectric conversion element 11R. The green filter 12G is located on the incident side of light relative to the green photoelectric conversion element 11G. The blue filter 12B is located on the incident side of light relative to the blue photoelectric conversion element 11B.

[0055] like Figure 2 As shown, the thickness T12 of the filters 12R, 12G, and 12B used for various colors can be approximately equal in size to each other, or they can be of different sizes. That is, the thickness of the red filter 12R, the green filter 12G, and the blue filter 12B may not all be of the same size. The thickness T12 of the filters 12R, 12G, and 12B used for various colors is, for example, greater than or equal to 0.5 μm and less than or equal to 5 μm.

[0056] Furthermore, the infrared cutoff filter 13's infrared light blocking function can be varied depending on its thickness T13. The thickness T13 of the infrared cutoff filter 13 can be varied based on the step difference between the filters 12R, 12G, and 12B used for various colors. Therefore, from the viewpoint of improving the flatness of the substrate of the infrared cutoff filter 13, it is preferable that the thickness T12 difference between the filters 12R, 12G, and 12B used for various colors is less than the thickness T13 of the infrared cutoff filter 13.

[0057] Color filters 12R, 12G, and 12B for various colors are formed by coatings containing coloring photosensitive resins and by patterning the coatings using photolithography. For example, a coating containing a red photosensitive resin is formed by applying a coating solution containing a red photosensitive resin and then drying the coating. A red color filter 12R is formed by exposing and developing a coating containing a red photosensitive resin. Furthermore, when the red photosensitive resin is a negative photosensitive resin, the portion of the coating containing the red photosensitive resin corresponding to the red color filter 12R is exposed. Conversely, when the red photosensitive resin is a positive photosensitive resin, the portion of the coating containing the red photosensitive resin corresponding to the area other than the red color filter 12R is exposed.

[0058] For the pigments contained in the coloring compositions of the red filter 12R, the green filter 12G, and the blue filter 12B, organic or inorganic pigments can be used alone, or two or more organic or inorganic pigments can be used in combination. The pigments are preferably pigments with high color rendering and high heat resistance, especially pigments with high resistance to thermal decomposition. Organic pigments are typically used. Examples of such pigments include phthalocyanines, azo compounds, anthraquinones, quinacridones, dioxazines, anthrones, indanones, perylene compounds, thioindoline compounds, isoindoline compounds, quinoline ketones, diketopyrrolopyrroles, and other organic pigments.

[0059] Below are specific examples of organic pigments that can be used in coloring compositions, indicated by color index numbers.

[0060] The blue pigment used in the blue coloring composition for filters of various colors can be, for example, CIPigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64, 81, etc. Among them, CIPigment Blue 15:6 is preferred as the blue pigment.

[0061] Purple pigments can be, for example, CIPigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50, etc. Among them, CIPigment Violet 23 is preferred as a purple pigment.

[0062] Yellow pigment can be CIPigment Yellow (pigment yellow) 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 11 Pigments including 7, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, and 214. Among these, CIPigmentYellow 13, 150, and 185 are preferred as yellow pigments.

[0063] Red coloring compositions are compositions that can be obtained by using red pigments instead of blue pigments, and by using pigments for color mixing as needed. Examples of red pigments include CIPigment Red 7, 9, 14, 41, 48:1, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 97, 122, 123, 146, 149, 168, 177, 178, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 246, 254, 255, 264, 272, and CIPigment Orange 36, 43, 51, 55, 59, 61, 71, 73, etc. For example, pigments used for color mixing can be CIPigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 11 8, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214, etc.

[0064] Furthermore, the green coloring composition is a composition obtained by using green pigments and tinting pigments instead of blue pigments, etc. Examples of green pigments include CIPigment Green 7, 10, 36, 37, 58, 59, etc. Tinting pigments can be yellow pigments, as listed in red coloring compositions, used for tinting.

[0065] The infrared cut-off filter 13 blocks the infrared light detectable by each photoelectric conversion element 11 relative to the photoelectric conversion element 11, thereby improving the detection accuracy of the photoelectric conversion element 11 for visible light. In other words, the infrared cut-off filter 13 suppresses the transmission of infrared light detectable by each photoelectric conversion element 11. The infrared light detectable by each photoelectric conversion element 11 is, for example, near-infrared light with a wavelength greater than or equal to 800 nm and less than or equal to 1000 nm. The infrared cut-off filter 13 is a layer that is universal for the red filter 12R, the green filter 12G, and the blue filter 12B. That is, one infrared cut-off filter 13 covers the red filter 12R, the green filter 12G, and the blue filter 12B.

[0066] The infrared cut-off filter 13 is made of a transparent resin containing infrared-absorbing pigments. Examples of infrared-absorbing pigments include anthraquinone pigments, anthocyanin pigments, phthalocyanine pigments, dithiol pigments, diimmonium-based dyes, squaric acid cyanine pigments, and ketone acid pigments. Examples of transparent resins include acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins. The infrared cut-off filter 13 is formed by film formation using methods such as coating.

[0067] The transmission spectrum of the preferred infrared cut-off filter 13 satisfies the following conditions [A1] to [A3].

[0068] [A1] In the wavelength band greater than or equal to 450 nm and less than or equal to 650 nm, the average transmittance is greater than or equal to 80%.

[0069] [A2] It has the maximum absorption rate in the wavelength band greater than or equal to 800 nm and less than or equal to 1000 nm.

[0070] [A3] The difference between the cutoff wavelength of the short wavelength side with 50% transmittance and the cutoff wavelength of the long wavelength side with 50% transmittance is a cutoff wavelength amplitude greater than or equal to 100 nm.

[0071] If the structure satisfies [A1], the absorption of visible light by the infrared cut-off filter 13 can be sufficiently suppressed. If the structure satisfies [A2] and [A3], the near-infrared light that can be detected by the photoelectric conversion element 11 for various colors can be sufficiently blocked by the infrared cut-off filter 13.

[0072] Furthermore, the blocking function of the barrier layer 14 against the oxidation source can be varied depending on the thickness of the barrier layer 14. Moreover, the thickness of the barrier layer 14 on the infrared cut-off filter 13 can be varied depending on the step difference on the upper surface of the infrared cut-off filter 13. Therefore, from the viewpoint of improving the flatness of the substrate of the barrier layer 14, it is preferable that the thickness T13 of the infrared cut-off filter 13 is a size that imparts appropriate flatness to the upper surface of the infrared cut-off filter 13. Appropriate flatness, for example, means that the step difference on the upper surface of the infrared cut-off filter 13 is less than three times the thickness of the barrier layer 14.

[0073] The aforementioned infrared-absorbing pigments come into contact with oxygen and water in the atmosphere when exposed to sunlight, thereby altering the transmission spectrum in the near-infrared band. In other words, the infrared cut-off filter 13 comes into contact with an oxidation source when exposed to sunlight, causing a decrease in its near-infrared light cut-off performance.

[0074] The barrier layer 14 suppresses the transmission of oxygen and water, which are the oxidation sources of the infrared cut-off filter 13, thereby suppressing the decrease in the cut-off performance of the infrared absorbing pigment to near-infrared light and suppressing the decrease in the transmission performance of visible light. The barrier layer 14 is a layer that is universal for the red filter 12R, the green filter 12G, and the blue filter 12B. That is, one barrier layer 14 covers the red filter 12R, the green filter 12G, and the blue filter 12B.

[0075] The barrier layer 14 can be made of an inorganic compound. The preferred material for the barrier layer 14 is a silicon compound. For example, the material for the barrier layer 14 may be at least one selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

[0076] The barrier layer 14 is formed by vapor phase deposition methods such as sputtering, CVD, and ion plating, or liquid phase deposition methods such as coating. For example, for a substrate on which the infrared cut-off filter 13 is formed, the barrier layer 14 is formed by sputtering a target material made of silicon oxide. For example, for a substrate on which the infrared cut-off filter 13 is formed, the barrier layer 14 is formed by CVD using silane and oxygen. For example, the barrier layer 14 is formed by coating, modifying, and drying a coating solution containing polysilazane.

[0077] The oxygen transmittance, thickness, and visible light transmittance of the preferred barrier layer 14 satisfy the following conditions [B1] or [B3].

[0078] [B1] Based on JIS K 7126-2:2006, the oxygen permeability is less than or equal to 5.0 cc / m³. 2 / day / atm. In other words, the oxygen permeability is less than or equal to 5.0cm.3 / m 2 / day / atm. Furthermore, the oxygen permeability is based on Annex A of JIS K 7126-2:2006, and is the oxygen permeability at 23°C and 50% relative humidity.

[0079] [B2] The thickness of the barrier layer 14 is greater than or equal to 10 nm and less than or equal to 500 nm.

[0080] [B3] The visible light transmittance (average) of the barrier layer 14 is greater than or equal to 90%.

[0081] If the structure satisfies [B1], it can sufficiently suppress the arrival of oxidation sources at the infrared cutoff filter 13, especially suppressing oxygen from reaching the infrared cutoff filter 13. Furthermore, from the viewpoint of further improving the lightfastness of the infrared cutoff filter 13, it is preferable that the oxygen transmittance is less than or equal to 3.0 cc / m 2 / day / atm, preferably less than or equal to 1.0cc / m 2 / day / atm, further preferably less than or equal to 0.7cc / m 2 / day / atm. In other words, the preferred oxygen permeability is less than or equal to 3.0cm. 3 / m 2 / day / atm, preferably less than or equal to 1.0cm 3 / m 2 / day / atm, further preferably less than or equal to 0.7cm 3 / m 2 / day / atm.

[0082] If the structure satisfies [B2], it is easy to select constituent materials that satisfy [B1] and [B3]. Furthermore, it can suppress the formation of cracks in the barrier layer 14. Additionally, if the structure satisfies [B3], it can effectively suppress the absorption of visible light by the barrier layer 14.

[0083] The barrier layer 14 may have a monolayer structure composed of a single compound, a stacked structure based on layers composed of a single compound, or a stacked structure based on layers composed of different compounds. For example, the barrier layer 14 may be a structure that satisfies [B1] by having a stacked structure based on layers that do not satisfy [B1] in the monolayer.

[0084] like Figure 1As shown, the microlenses for various colors consist of a red microlens 15R, a green microlens 15G, and a blue microlens 15B. The red microlens 15R is located on the light incident side relative to the red filter 12R. The green microlens 15G is located on the light incident side relative to the green filter 12G. The blue microlens 15B is located on the light incident side relative to the blue filter 12B.

[0085] Microlenses 15R, 15G, and 15B for various colors have an incident surface 15S as their outer surface. To ensure that light entering the incident surface 15S converges towards the photoelectric conversion elements 11R, 11G, and 11B for various colors, the microlenses 15R, 15G, and 15B for various colors have a specified refractive index difference relative to the refractive index of the external atmosphere.

[0086] Microlenses 15R, 15G, and 15B for various colors are formed by creating a coating containing a transparent resin, patterning the coating using photolithography, and reflowing based on heat treatment. Transparent resins include, for example, acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins.

[0087] As described above, according to the first embodiment of the filter for a solid-state imaging element and the solid-state imaging element, the effects described below can be obtained.

[0088] (1-1) The barrier layer 14 inhibits the oxidation source from reaching the infrared cut-off filter 13, so the infrared cut-off filter 13 is not easily oxidized by the oxidation source. As a result, the light resistance of the infrared cut-off filter 13 can be improved, and thus the light resistance of the solid-state imaging element can be improved.

[0089] (1-2) If the structure satisfies [B1], the effect based on (1-1) above can be obtained, especially the oxidation of the infrared cutoff filter 13 caused by oxygen can be suppressed.

[0090] (1-3) If the thickness T13 of the infrared cut-off filter 13 is such that it can impart appropriate flatness to the upper surface of the infrared cut-off filter 13, it can also suppress fluctuations based on the effects of (1-1) and (1-2) above.

[0091] (1-4) The greater the difference in thickness T12 between the filters 12R, 12G, and 12B for various colors, the greater the thickness T13 used to impart appropriate flatness to the upper surface of the infrared cut-off filter 13. Therefore, if the structure has a thickness T12 difference between the filters 12R, 12G, and 12B for various colors that is less than the thickness T13 of the infrared cut-off filter 13, the thickness T13 used to achieve the effect based on (1-3) can be reduced. As a result, the thickness T13 of the infrared cut-off filter 13 can be set to a size specifically designed to cut off infrared light.

[0092] Furthermore, the first embodiment described above can be modified in the following ways.

[0093] [Amendment Example 1]

[0094] ·like Figure 3 As shown, the blocking layer 14 is not limited to the space between the infrared cut-off filter 13 and the microlenses 15R, 15G, and 15B for various colors; it can also be located on the outer surface of the microlenses 15R, 15G, and 15B for various colors. In this case, the outer surface of the blocking layer 14 functions as the incident surface for light to be incident on the solid-state imaging element. In short, the position of the blocking layer 14 only needs to be on the light incident side relative to the infrared cut-off filter 13.

[0095] (1-5) According to the first modified example, the barrier layer 14 is located on the optical surface (flat surface) of the microlenses 15R, 15G, and 15B for various colors. As a result, the thickness of the barrier layer 14 can be easily made uniform, and thus the barrier function of the barrier layer 14 in blocking the oxidation source can also be easily made uniform.

[0096] (1-6) In the structure of the first modified example, it is preferable that the refractive index of the barrier layer 14 is lower than that of the microlenses 15R, 15G, and 15B used for various colors. Furthermore, it is more preferable that the difference between the refractive index of the microlenses 15R, 15G, and 15B used for various colors and the refractive index of the barrier layer 14 is greater than or equal to 0.1. According to this structure, the refractive index difference between air and the microlenses used for various colors can be reduced, thus suppressing reflected light generated on the incident surface side.

[0097] (1-7) Preferably, the barrier layer 14 also has an anti-reflective function for visible light. If the barrier layer 14 has an anti-reflective function, it can also suppress the decrease in detection sensitivity caused by reflection from the incident surface. Furthermore, since the barrier layer 14, which suppresses the transmission of the oxidation source, also has an anti-reflective function, the layer structure of the filter 10 for the solid-state imaging element can be simplified compared to other structures with anti-reflection layers. The anti-reflective function can be achieved by the difference in refractive index between the barrier layer 14 and other layers, or by the barrier layer 14 containing filler, or by giving the barrier layer 14 an embossed shape so that the barrier layer 14 has an uneven shape.

[0098] [Second Amendment Example]

[0099] ·like Figure 4 As shown, layers other than the infrared cut-off filter 13 can also perform the cut-off function of the infrared cut-off filter 13. For example, microlenses 15R, 15G, and 15B for various colors can also perform the cut-off function of infrared cut-off filters. That is, regarding the filter 10 for solid-state imaging elements, the constituent materials of the microlenses 15R, 15G, and 15B for various colors can contain infrared-absorbing pigments. Thus, the filter 10 for solid-state imaging elements can be modified to a structure that eliminates the infrared cut-off filter 13.

[0100] (1-8) If the structure of the microlenses 15R, 15G, 15B used for various colors also has an infrared cutoff function, the layer structure of the filter 10 for solid-state imaging elements can be simplified.

[0101] [Third Amendment Example]

[0102] ·like Figure 5 As shown, filters 12R, 12G, and 12 used for various colors tend to have different thicknesses, thus converting different colors of light into the same intensity. As a result, a filter for one color tends to create a step difference between filters for other colors. In this case, the infrared cut-off filter 13 tends to have a shape that follows the step difference formed between the different color filters. As described above, the shape of the infrared cut-off filter 13 following the step difference causes fluctuations in the thickness of the blocking layer 14, and consequently, fluctuations in the blocking function of the oxide source.

[0103] Therefore, the solid-state imaging element filter 10 may further have a planarization layer 21 between the infrared cut-off filter 13 and the blocking layer 14. The planarization layer 21 has light transmittance that allows visible light to pass through, and the surface of the planarization layer 21 has a flat surface that fills the step difference formed by the infrared cut-off filter 13. That is, the planarization layer 21 has a shape that can gently reduce the height difference on the surface of the infrared cut-off filter 13.

[0104] The planarization layer 21 is made of a transparent resin. Examples of transparent resins include acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins. The planarization layer 21 is formed by a liquid-phase film-forming method such as coating.

[0105] (1-9) If the solid-state imaging element filter 10 has a structure with a planarization layer 21, the effect based on (1-3) above can be obtained, and the limitations on planarization can be removed from the thickness T13 of the infrared cut-off filter 13 and the thickness T12 of the filters 12R, 12G, and 12B for various colors.

[0106] [Amendment Example 4]

[0107] ·like Figure 6 As shown, the solid-state imaging element filter 10 may further have a planarization layer 22 between the color filters 12R, 12G, 12B and the infrared cut-off filter 13. The material and method of forming the planarization layer 22 may be the same as those described in the third modified example.

[0108] (1-10) If it is another structure with a planarization layer 22, the effect based on (1-3) above can be obtained, and the infrared cut-off filter 13 can be easily homogenized to cut off infrared light.

[0109] [Fifth Amendment Example]

[0110] ·like Figure 7 As shown, the position of the infrared cut-off filter 13 is not limited to between the filters 12R, 12G, and 12B for various colors and the blocking layer 14. For example, the position of the infrared cut-off filter 13 can be changed to between each photoelectric conversion element 11 and the filters 12R, 12G, and 12B for various colors. In short, the infrared cut-off filter 13 only needs to be positioned between the blocking layer 14 and each photoelectric conversion element 11.

[0111] [Amendment 6]

[0112] ·like Figure 8As shown, the positions of the infrared cut-off filter 13 and the blocking layer 14 are not limited to those between the microlenses 15R, 15G, and 15B for various colors and the filters 12R, 12G, and 12B for various colors. The positions of the infrared cut-off filter 13 and the blocking layer 14 can be changed to be between the filters 12R, 12G, and 12B for various colors and each photoelectric conversion element 11. In short, the positions of the infrared cut-off filter 13 and the blocking layer 14 are only required to be on the light incident side relative to each photoelectric conversion element 11.

[0113] [Amendment 7]

[0114] ·like Figure 9 As shown, the plurality of photoelectric conversion elements 11 may include an infrared photoelectric conversion element 11P for measuring the intensity of infrared light. In this case, the solid-state imaging element filter 10 has an infrared bandpass filter 12P on the light incident side relative to the infrared photoelectric conversion element 11P.

[0115] The infrared bandpass filter 12P blocks visible light that can be detected by the infrared photoelectric conversion element 11P, thereby improving the detection accuracy of infrared light by the infrared photoelectric conversion element 11P. The infrared light that the infrared photoelectric conversion element 11P can detect is, for example, near-infrared light with a wavelength greater than or equal to 800 nm and less than or equal to 1200 nm. The infrared bandpass filter 12P is formed by forming a coating containing a black photosensitive resin and patterning the coating using photolithography.

[0116] The infrared cut-off filter 13 has a through-hole 13H on the light incident side relative to the infrared bandpass filter 12P, thus the infrared cut-off filter 13 is not located on the light incident side relative to the infrared bandpass filter 12P. The infrared cut-off filter 13 is applicable to the red filter 12R, the green filter 12G, and the blue filter 12B. That is, one infrared cut-off filter 13 covers the red filter 12R, the green filter 12G, and the blue filter 12B.

[0117] The through-holes 13H in the infrared cut-off filter 13 are formed by a patterning process such as photolithography or dry etching. When the through-holes 13H are formed by photolithography, a photosensitive composition containing an infrared-absorbing pigment is used as the constituent material of the infrared cut-off filter 13. The photosensitive composition may contain a binder resin, a photopolymerization initiator, a polymerizable monomer, an organic solvent, a leveling agent, etc.

[0118] The adhesive resin can be, for example, acrylic resin, polyamide resin, polyimide resin, polyurethane resin, polyester resin, polyether resin, polyolefin resin, polycarbonate resin, polystyrene resin, or norbornene resin.

[0119] Photopolymerization initiators can be acetophenone-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzophenone-based photopolymerization initiators, thioxanone-based photopolymerization initiators, triazine-based photopolymerization initiators, oxime ester-based photopolymerization initiators, etc. One of these photopolymerization initiators can be used alone, or two or more photopolymerization initiators can be used in combination.

[0120] Polymerizable monomers can be (meth)acrylic acid, (meth)acrylate, (meth)ethyl acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, (tert-butyl acrylate), (meth)acrylate, ... For polymerizable monomers, one of the monomers mentioned above can be used alone, or two or more of the monomers mentioned above can be used in combination.

[0121] Organic solvents can be, for example, ethyl lactate, benzyl alcohol, 1,2,3-trichloropropane, 1,3-butanediol, 1,3-butanediol, 1,3-butanediol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-1,3-propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, and 3-methoxy-3-methylacetic acid. Butyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N,N-dimethylacetamide, N,N-dimethylformamide, n-butanol, n-butanyl acetate, o-xylene, o-chlorotoluene, o-diethylbenzene, o-dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butanylene, tert-butanylene, γ-butyrolactone, isobutanol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate Ethylene glycol monotert-butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether The following solvents are listed: dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methyl cyclohexanol, N-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, diesters, etc. For organic solvents, one of the above solvents can be used alone, or two or more of the above solvents can be used in combination.

[0122] The leveling agent is preferably a dimethylsiloxane having a polyether structure or a polyester structure in its main chain. Examples of dimethylsiloxanes having a polyether structure in their main chain include FZ-2122 manufactured by Higashi Re Dow Corning Co., Ltd., and BYK-333 manufactured by Bick Kemming Co., Ltd. Examples of dimethylsiloxanes having a polyester structure include BYK-310 and BYK-370 manufactured by Bick Kemming Co., Ltd. Both dimethylsiloxanes with a polyether structure and dimethylsiloxanes with a polyester structure can be used as leveling agents. One of the above-mentioned leveling agents can be used alone, or two or more of the above-mentioned leveling agents can be used in combination.

[0123] When the through-hole 13H of the infrared cut-off filter 13 is formed using a dry etching method, the constituent material of the infrared cut-off filter 13 is a curable composition containing an infrared absorbing pigment. The curable composition contains a transparent resin. Examples of transparent resins include acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins.

[0124] The barrier layer 14 has a through-hole 14H on the light incident side relative to the infrared bandpass filter 12P. Therefore, the barrier layer 14 is not located on the light incident side relative to the infrared bandpass filter 12P. The barrier layer 14 is applicable to the red filter 12R, the green filter 12G, and the blue filter 12B. That is, one barrier layer 14 covers the red filter 12R, the green filter 12G, and the blue filter 12B.

[0125] For the formation of the through-hole 14H in the barrier layer 14, any processing method can be used as long as it can penetrate the barrier layer 14 to form a hole. For example, the through-hole 14H can be formed using a method such as dry etching.

[0126] The filters 12R, 12G, and 12B used for various colors are thinner than the infrared bandpass filter 12P. The combined thickness of the infrared cutoff filter 13 and the barrier layer 14 is equivalent to the difference between the thickness of the filters 12R, 12G, and 12B used for various colors and the thickness of the infrared bandpass filter 12P.

[0127] (1-11) According to the seventh modification, the light resistance of the infrared cut-off filter 13 can be improved, and the measurement of visible light by photoelectric conversion elements 11R, 11G, 11B for various colors and the measurement of infrared light by photoelectric conversion element 11P for infrared light can be realized.

[0128] (1-12) The thickness of the infrared bandpass filter 12P, which cuts off visible light, is easily greater than the thickness of the filters 12R, 12G, and 12B used for various colors. On the other hand, the step difference TP between the infrared bandpass filter 12P and the filters 12R, 12G, and 12B used for various colors is filled by the infrared cutoff filter 13 and the blocking layer 14. Therefore, even with a structure that generates a step difference TP between the filters 12R, 12G, and 12B used for various colors and the infrared bandpass filter 12P, it is easy to obtain the flatness of the lower layer of the microlenses 15R, 15G, and 15B used for various colors and the infrared microlens 15P.

[0129] [other]

[0130] The solid-state imaging element can have an anchoring layer between the barrier layer 14 and its lower layer. This anchoring layer improves the adhesion between the barrier layer 14 and its lower layer. Alternatively, the solid-state imaging element can also have an anchoring layer between the barrier layer 14 and its upper layer. This anchoring layer further improves the adhesion between the barrier layer 14 and its upper layer.

[0131] The anchoring layer is made of materials such as multifunctional acrylic resin or silane coupling agent. The thickness of the anchoring layer is, for example, greater than or equal to 50 nm and less than or equal to 1 μm. If the thickness of the anchoring layer is greater than or equal to 50 nm, it is easier to achieve tight adhesion between layers. If the thickness of the anchoring layer is less than or equal to 1 μm, it is easier to suppress light absorption by the anchoring layer.

[0132] The multiple photoelectric conversion elements 11 can be composed of organic and inorganic photoelectric conversion elements. Therefore, the filters 12R, 12G, and 12B used for various colors can be omitted. Even if the structure of the filters 12R, 12G, and 12B used for various colors is omitted, the infrared cut-off filter 13 is protected because the solid-state imaging element filter 10 has an infrared cut-off filter 13 and the aforementioned blocking function.

[0133] The solid-state imaging element filter 10 may have a black matrix and a planarization layer between multiple photoelectric conversion elements 11 and the color filters 12R, 12G, and 12B. The black matrix suppresses light of various colors selected by the color filters 12R, 12G, and 12B from entering the photoelectric conversion elements 11 for other colors. The planarization layer fills in the step difference of the black matrix, thereby planarizing the substrates of the color filters 12R, 12G, and 12B, as well as the substrate of the infrared cut-off filter 13. As a result, the planarization layer planarizes the substrate of the blocking layer 14.

[0134] • The color filter can be changed to a three-color filter consisting of a cyan filter, a yellow filter, and a magenta filter. Alternatively, the color filter can be changed to a four-color filter consisting of a cyan filter, a yellow filter, a magenta filter, and a black filter. Furthermore, the color filter can be changed to a four-color filter consisting of a transparent filter, a yellow filter, a red filter, and a black filter.

[0135] The refractive indices of the filters 12R, 12G, and 12B used for various colors are, for example, greater than or equal to 1.6 and less than or equal to 1.9. The refractive indices of each microlens 15R, 15G, and 15B are, for example, greater than or equal to 1.4 and less than or equal to 2.0. More preferably, the refractive indices of each microlens 15R, 15G, and 15B are greater than or equal to 1.5 and less than or equal to 1.7. The constituent materials of the infrared cut-off filter 13 and the infrared bandpass filter 12P may contain inorganic oxide particles to suppress the difference in refractive indices of the filters 12R, 12G, and 12B used for various colors and the microlenses 15R, 15G, and 15B. Inorganic oxides are, for example, aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide.

[0136] The constituent materials of the infrared cut-off filter 13 and the infrared bandpass filter 12P may contain additives such as light stabilizers, antioxidants, heat stabilizers, and antistatic agents to provide additional functions.

[0137] • The solid-state imaging element can be modified to omit the barrier layer 14, and the oxygen transmittance of the stacked structure located on the incident surface 15S side relative to the infrared cut-off filter 13 is less than or equal to 5.0 cc / m 2 The structure can be / day / atm. For example, the laminated structure can have filters 12R, 12G, 12B for various colors, a planarization layer, and microlenses 15R, 15G, 15B for various colors. The oxygen permeability of this laminated structure can be less than or equal to 5.0 cc / m. 2 / day / atm.

[0138] [Second Implementation]

[0139] Below, refer to Figures 10 to 12 A second embodiment of the solid-state imaging element will be described. Figure 10 This is a schematic structural diagram showing the individual layers of a portion of a solid-state imaging element.

[0140] like Figure 10 As shown, the solid-state imaging element includes a solid-state imaging element filter 10 and multiple photoelectric conversion elements 11. The solid-state imaging element filter 10 includes filters 12R, 12G, and 12B for various colors, an infrared bandpass filter 12P, a blocking layer 14, and microlenses 15R, 15G, 15B, and 15P. The infrared bandpass filter 12P is an example of an infrared filter.

[0141] Color filters 12R, 12G, and 12B are located between the photoelectric conversion elements 11R, 11G, and 11B for the three colors and the microlenses 15R, 15G, and 15B. An infrared bandpass filter 12P is located between the infrared photoelectric conversion element 11P and the microlens 15P. A blocking layer 14 is located between the infrared bandpass filter 12P and the infrared microlens 15P. The blocking layer 14 is located on the light incident side relative to the infrared bandpass filter 12P.

[0142] The photoelectric conversion element 11 for three colors is an example of a first photoelectric conversion element, composed of a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, and a blue photoelectric conversion element 11B. The infrared photoelectric conversion element 11P is an example of a second photoelectric conversion element. The solid-state imaging element has multiple red photoelectric conversion elements 11R, multiple green photoelectric conversion elements 11G, multiple blue photoelectric conversion elements 11B, and multiple infrared photoelectric conversion elements 11P. Figure 10 The image shows a repeating unit of the photoelectric conversion element 11 of the solid-state imaging element.

[0143] like Figure 11 As shown, the thickness T12 of the filters 12R, 12G, and 12B used for various colors can be different in size from that of the infrared bandpass filter 12P, or they can be the same size. The thickness T12 of the filters 12R, 12G, and 12B used for various colors is, for example, greater than or equal to 0.5 μm and less than or equal to 5 μm.

[0144] Furthermore, the infrared bandpass filter 12P's infrared light transmission function can be varied depending on its thickness T12. Moreover, the microlenses 15R, 15G, 15B on the filters 12R, 12G, 12B for various colors, and the microlens 15P on the blocking layer 14 can have their processing precision reduced depending on the step difference between the filters 12R, 12G, 12B and the blocking layer 14. Therefore, from the viewpoint of improving the flatness of the substrates of each microlens 15R, 15G, 15B, 15P, it is preferable that the combined thickness T12 of the infrared bandpass filter 12P and the thickness T14 of the blocking layer 14 is approximately equal to the thickness of the filters 12R, 12G, 12B for various colors.

[0145] The infrared bandpass filter 12P blocks visible light detectable by the infrared photoelectric conversion element 11P, thereby improving the detection accuracy of near-infrared light by the infrared photoelectric conversion element 11P. In other words, the infrared bandpass filter 12P suppresses the transmission of visible light detectable by the infrared photoelectric conversion element 11P. The infrared bandpass filter 12P is a layer located solely on the infrared photoelectric conversion element 11P.

[0146] The infrared bandpass filter 12P is composed of a black pigment or black dye and a transparent resin. The black pigment is a single pigment that is black, or a mixture of two or more pigments that are black. Examples of black dyes include azo dyes, anthraquinone dyes, azazine dyes, quinoline dyes, pyridone dyes, perylene dyes, and methyl alkali dyes. Examples of transparent resins include acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins. The infrared bandpass filter 12P is formed by liquid-phase film formation methods such as coating.

[0147] The constituent materials of the infrared bandpass filter 12P may contain particles of inorganic oxides used to adjust the refractive index of the infrared bandpass filter 12P. Inorganic oxides include, for example, aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide. The infrared bandpass filter 12P may also contain additives such as light stabilizers, antioxidants, heat stabilizers, and antistatic agents to provide additional functions.

[0148] like Figure 12 As shown, the infrared bandpass filter 12P exhibits a transmittance of less than or equal to 3% in the wavelength range of 400 nm or greater and 700 nm or less. On the other hand, the infrared bandpass filter 12P has a transmittance of greater than or equal to 10% at a wavelength of 850 nm, and greater than or equal to 90% at wavelengths of 900 nm or greater.

[0149] The solar spectrum has an absorption band near a wavelength of 940 nm due to water vapor absorption. Therefore, the spectral intensity of the solar spectrum decreases near a wavelength of 940 nm. Consequently, near-infrared light with a wavelength of 940 nm is less susceptible to interference from sunlight, which is an external source of interference, when using a solid-state imaging element outdoors during the day. That is, if the center wavelength of the light source used is 940 nm, a solid-state imaging element with less noise can be provided. Near-infrared light with a wavelength of 940 nm is detected using an infrared photoelectric conversion element 11P.

[0150] The barrier layer 14 suppresses the transmission of oxygen and water, which are the oxidation sources of the infrared bandpass filter 12P. This suppresses the decrease in visible light cutoff performance caused by black pigments and dyes, and also suppresses the decrease in near-infrared light transmission performance. The barrier layer 14 is located on the incident surface 15S side relative to the infrared bandpass filter 12P, but not on the incident surface 15S side relative to the filters 12R, 12G, and 12B used for various colors. That is, the barrier layer 14 covers the infrared bandpass filter 12P, but does not cover the filters 12R, 12G, and 12B used for various colors.

[0151] The oxygen transmittance, thickness, and visible light transmittance of the barrier layer 14 are the same as those of the barrier layer 14 in the first embodiment, and preferably satisfy the conditions [B1] or [B3] described above.

[0152] If the structure satisfies [B1], it can sufficiently suppress the arrival of oxidation sources at the infrared bandpass filter 12P, especially suppressing oxygen from reaching the infrared bandpass filter 12P. Furthermore, from the viewpoint of further improving the lightfastness of the infrared cutoff filter 13, it is preferable that the oxygen transmittance is less than or equal to 3.0 cc / m 2 / day / atm, preferably less than or equal to 1.0cc / m 2 / day / atm, further preferably less than or equal to 0.7cc / m 2 / day / atm.

[0153] If the structure satisfies [B2], it is easy to select constituent materials that satisfy [B1] and [B3]. Moreover, it is also possible to suppress the formation of cracks in the barrier layer 14. If the structure satisfies [B3], it is possible to sufficiently suppress the absorption of visible light by the barrier layer 14.

[0154] As described above, according to the second embodiment of the filter for a solid-state imaging element and the solid-state imaging element, the effects described below can be obtained.

[0155] (2-1) The barrier layer 14 inhibits the oxidation source from reaching the infrared bandpass filter 12P, so the infrared bandpass filter 12P is not easily oxidized by the oxidation source. As a result, the light resistance of the infrared bandpass filter 12P and thus the light resistance of the solid-state imaging element can be improved.

[0156] (2-2) If the structure satisfies [B1], it can also achieve the effect based on (2-1) above, especially suppressing the oxidation of the infrared bandpass filter 12P caused by oxygen.

[0157] (2-3) If the combined thickness T12 of the infrared bandpass filter 12P and the thickness T14 of the blocking layer 14 is approximately the same as that of the filters 12R, 12G, and 12B used for various colors, then a high degree of flatness can be obtained on the substrate of the microlenses 15R, 15G, 15B, and 15P. As a result, fluctuations in the processing and shape of the microlenses 15R, 15G, 15B, and 15P can also be suppressed.

[0158] Furthermore, the second embodiment described above can be modified in the following ways.

[0159] [Amendment Example 1]

[0160] like Figure 13 As shown, the blocking layer 14 can be disposed on the incident side of light relative to the infrared bandpass filter 12P and the filters 12R, 12G, and 12B for various colors. That is, the blocking layer 14 can be disposed on the entire incident surface 15S side relative to each photoelectric conversion element 11.

[0161] (2-4) If the barrier layer 14 is located on the entire incident surface 15S side relative to each photoelectric conversion element 11, the barrier layer 14 can be formed using a method that forms the barrier layer 14 over the entire film-forming object. Moreover, there is no need for a separate process of removing the barrier layer 14 from above the filters 12R, 12G, and 12B for various colors, thus simplifying the method for forming a solid-state imaging element.

[0162] (2-5) The incident surface 15S side of the filters 12R, 12G, and 12B for various colors adjacent to the infrared bandpass filter 12P is also covered by the blocking layer 14, thus further effectively suppressing the oxidation of the infrared bandpass filter 12P.

[0163] [Second Amendment Example]

[0164] like Figure 14 As shown, the infrared bandpass filter 12P, which cuts off the entire wavelength region of visible light, tends to have a different thickness than the filters 12R, 12G, and 12B used for various colors. As a result, a step difference is easily formed between the infrared bandpass filter 12P and the filters 12R, 12G, and 12B used for various colors. In this case, the upper surface and a portion of the peripheral surface of the infrared bandpass filter 12P are exposed from the filters 12R, 12G, and 12B used for various colors.

[0165] Furthermore, as in the first modified example, when the blocking layer 14 is located on the entire incident surface 15S side of each photoelectric conversion element 11, the blocking layer 14 tends to have a shape that follows a step difference between the infrared bandpass filter 12P and the filters 12R, 12G, and 12B for various colors. The shape of the blocking layer 14 that follows the step difference causes fluctuations in the thickness of the blocking layer 14, which in turn causes fluctuations in the blocking function of the oxide source. In particular, the blocking function of the oxide source may decrease in a portion of the peripheral surface of the infrared bandpass filter 12P.

[0166] Therefore, a planarization layer 23 can also be provided between the infrared bandpass filter 12P and the filters 12R, 12G, and 12B for various colors and the blocking layer 14. The planarization layer 23 has light transmittance that allows visible light to pass through, and the surface of the planarization layer 23 has a flat surface that fills the step difference formed by the infrared bandpass filter 12P. That is, the planarization layer 23 has a shape that can mitigate the height difference formed by the infrared bandpass filter 12P and the filters 12R, 12G, and 12B for various colors.

[0167] The material constituting the planarization layer 23 may be a material that can be used in the planarization layer 21 of the first embodiment.

[0168] (2-6) If the structure has a planarization layer 23, the effects based on (2-1) and (2-5) can be obtained even if a portion of the peripheral surface of the infrared bandpass filter 12P is exposed from the filters 12R, 12G, and 12B for various colors.

[0169] [Third Amendment Example]

[0170] like Figure 15 As shown, the solid-state imaging element also has an infrared cut-off filter 13. The infrared cut-off filter 13 blocks infrared light detectable by the photoelectric conversion elements 11R, 11G, and 11B for various colors, thereby improving the detection accuracy of the photoelectric conversion elements 11 for visible light. The infrared light detectable by each photoelectric conversion element 11 is, for example, near-infrared light with a wavelength greater than or equal to 800 nm and less than or equal to 1000 nm. The infrared cut-off filter 13 is a layer that is universal for the red filter 12R, the green filter 12G, and the blue filter 12B. That is, one infrared cut-off filter 13 covers the red filter 12R, the green filter 12G, and the blue filter 12B.

[0171] The infrared cut-off filter 13 is located on the light incident side relative to the filters 12R, 12G, and 12B used for various colors. The infrared cut-off filter 13 has a through-hole 13H on the light incident side relative to the infrared bandpass filter 12P, but is not located on the light incident side relative to the infrared bandpass filter 12P.

[0172] Furthermore, the infrared cutoff filter 13's infrared light blocking function can be varied depending on its thickness. The thickness of the infrared cutoff filter 13 can be varied on and between the various color filters 12R, 12G, and 12B, based on the step difference between them. Therefore, from the viewpoint of improving the flatness of the substrate of the infrared cutoff filter 13, it is preferable that the thickness difference between the various color filters 12R, 12G, and 12B is less than the thickness of the infrared cutoff filter 13.

[0173] like Figure 16 As shown, the filters 12R, 12G, and 12B for various colors are thinner than the infrared bandpass filter 12P. In this case, it is preferable that the infrared cutoff filter 13 has a thickness equivalent to the difference in film thickness between the filters 12R, 12G, and 12B for various colors and the infrared bandpass filter 12P.

[0174] exist Figure 16 In the example shown, the incident surface of the infrared bandpass filter 12P and the incident surface of the infrared cutoff filter 13 are at the same height. That is, the surface of the infrared bandpass filter 12P that contacts the blocking layer 14 and the surface of the infrared cutoff filter 13 that contacts the blocking layer 14 are at the same height. In other words, the incident surface of the infrared bandpass filter 12P and the incident surface of the infrared cutoff filter 13 are coplanar.

[0175] The transmission spectrum of the preferred infrared cut-off filter 13 satisfies the conditions [A1] to [A3] above.

[0176] If the structure satisfies [A1], the absorption of visible light by the infrared cut-off filter 13 can be sufficiently suppressed. If the structure satisfies [A2] and [A3], the near-infrared light that can be detected by the photoelectric conversion element 11 for various colors can be sufficiently blocked by the infrared cut-off filter 13, and the blocking of visible light can be sufficiently suppressed.

[0177] (2-7) When infrared absorbing pigments come into contact with oxygen and water in the atmosphere under sunlight, the transmission spectrum of the near-infrared band changes. That is, when the infrared cut-off filter 13 comes into contact with the oxidation source under sunlight, the cut-off performance of near-infrared light decreases. In this respect, the blocking layer 14 is also located on the incident surface 15S side of the infrared cut-off filter 13, thus also improving the light resistance of the infrared cut-off filter 13.

[0178] (2-8) A single barrier layer 14 can improve the light resistance of the infrared bandpass filter 12P and the infrared cutoff filter 13, and thus can simplify the layer structure of the solid imaging element compared with structures having different barrier layers.

[0179] (2-9) If the combined thickness of the infrared cut-off filter 13 and the thicknesses of the filters 12R, 12G, and 12B for various colors is equivalent to the thickness of the infrared bandpass filter 12P, then the lower surface of the blocking layer 14 can be given appropriate flatness. As a result, fluctuations based on the effects described in (2-1) and (2-7) above can also be suppressed.

[0180] [other]

[0181] The blocking layer 14 is not limited to the area between the infrared bandpass filter 12P and the infrared microlens 15P; it can also be located on the outer surface of the infrared microlens 15P. In this case, the outer surface of the blocking layer 14 functions as the incident surface for light to be incident on the solid-state imaging element. In short, the blocking layer 14 only needs to be positioned on the light incident side relative to the infrared bandpass filter 12P. According to this structure, the blocking layer 14 is located on the optical surface (flat surface) of the infrared microlens 15P. As a result, it is easy to achieve uniformity in the thickness of the blocking layer 14, and thus, it is easy to achieve uniformity in the blocking function of the blocking layer 14 against the oxide source.

[0182] The solid-state imaging element can have an anchoring layer between the barrier layer 14 and its lower layer. This anchoring layer improves the adhesion between the barrier layer 14 and its lower layer. Alternatively, the solid-state imaging element can have an anchoring layer between the barrier layer 14 and its upper layer. This anchoring layer also improves the adhesion between the barrier layer 14 and its upper layer.

[0183] The constituent materials and thickness of the anchoring layer can be the same as those of the anchoring layer in the modified example of the first embodiment.

[0184] The multiple photoelectric conversion elements 11 are composed of organic and inorganic photoelectric conversion elements. Therefore, the filters 12R, 12G, and 12B used for various colors can be omitted in the filter 10 for the solid-state imaging element. Even if the structure omits the filters 12R, 12G, and 12B used for various colors, if it has an infrared bandpass filter 12P, the transmission function of the infrared bandpass filter 12P can be protected due to the aforementioned blocking function.

[0185] The solid-state imaging element filter 10 may have a black matrix and a planarization layer between multiple photoelectric conversion elements 11 and the color filters 12R, 12G, 12B and the infrared bandpass filter 12P. The black matrix suppresses light of various colors selected by the color filters 12R, 12G, 12B from entering the photoelectric conversion elements 11 for other colors. The planarization layer fills the step difference of the black matrix, thereby enabling planarization of the substrates of the color filters 12R, 12G, 12B, the infrared bandpass filter 12P, and the infrared cutoff filter 13. As a result, the planarization layer planarizes the substrate of the blocking layer 14.

[0186] • The color filter can be changed to a three-color filter consisting of a cyan filter, a yellow filter, and a magenta filter. Alternatively, the color filter can be changed to a four-color filter consisting of a cyan filter, a yellow filter, a magenta filter, and a black filter. Furthermore, the color filter can be changed to a four-color filter consisting of a transparent filter, a yellow filter, a red filter, and a black filter.

[0187] The refractive indices of the filters 12R, 12G, and 12B used for various colors are, for example, greater than or equal to 1.7 and less than or equal to 1.9. The refractive indices of the microlenses 15R, 15G, and 15B are, for example, greater than or equal to 1.5 and less than or equal to 1.6. The materials constituting the infrared bandpass filter 12P and the infrared cutoff filter 13 may contain inorganic oxide particles to suppress the difference in refractive index with the filters 12R, 12G, and 12B used for various colors and the microlenses 15R, 15G, and 15B. Examples of inorganic oxides include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide.

[0188] The materials constituting the infrared bandpass filter 12P and the infrared cutoff filter 13 may contain light stabilizers, antioxidants, heat stabilizers, antistatic agents, and other additives that also have other functions.

[0189] • The solid-state imaging element can be modified to omit the barrier layer 14, and the oxygen transmittance of the stacked structure located on the incident surface 15S side relative to the infrared bandpass filter 12P is less than or equal to 5.0 cc / m2 A structure with a density of / day / atm. For example, the stacked structure is formed by a planarization layer and other functional layers such as a bonding layer. This stacked structure can be formed together with an infrared microlens 15P to have a density of less than or equal to 5.0cc / m. 2 The structure of oxygen permeability per day / atm.

[0190] The solid-state imaging element may have a bandpass filter on the light incident surface side relative to multiple microlenses. The bandpass filter is a filter that allows specific wavelengths of visible and near-infrared light to pass through, and has the same function as the infrared cut-off filter 13. That is, it can block unwanted infrared light that can be detected by photoelectric conversion elements 11R, 11G, 11B for various colors and photoelectric conversion element 11P for infrared use. This improves the detection accuracy of visible light for photoelectric conversion elements 11R, 11G, 11B for various colors and near-infrared light with wavelengths in the 850nm or 940nm band for the detection object of photoelectric conversion element 11P for infrared use.

[0191] Explanation of the label

[0192] 10… Filters for solid-state imaging elements

[0193] 11… Photoelectric conversion element

[0194] 11R…Red photoelectric conversion element

[0195] 11G…Green photoelectric conversion element

[0196] 11B…Blue photoelectric conversion element

[0197] 11P…Infrared photoelectric conversion element

[0198] 12R…Red filter

[0199] 12G… Green filter

[0200] 12B…Blue filter

[0201] 12P…Infrared bandpass filter

[0202] 13…Infrared cut-off filter

[0203] 14…Barrier layer

[0204] 15R…Red with microlenses

[0205] 15G… Green Microlenses

[0206] 15B…Blue with microlenses

[0207] 15P…Infrared Microlens

[0208] 15s…incident surface

[0209] 21, 22, 23... Planarization layers

Claims

1. A filter for a solid-state imaging element, comprising: The incident surface of light; An infrared filter, located on the incident surface side relative to the photoelectric conversion element; and A barrier layer, located on the incident surface side relative to the infrared filter, suppresses the transmission of oxidation sources that could oxidize the infrared filter. The barrier layer simultaneously satisfies the following [B1] to [B3]: [B1] Oxygen permeability less than or equal to 5.0 cm⁻¹ 3 / m 2 / day / atm; [B2] Thickness greater than or equal to 10 nm and less than or equal to 500 nm; and [B3] The average transmittance in the visible light region is greater than or equal to 90%. The infrared filter is an infrared cutoff filter. The transmission spectrum of the infrared cut-off filter simultaneously satisfies the following [A1] to [A3]: [A1] In a wavelength band greater than or equal to 450 nm and less than or equal to 650 nm, the average transmittance is greater than or equal to 80%. [A2] It has the maximum absorption rate in the wavelength band of 800 nm or more and 1000 nm or less; as well as [A3] The difference between the cutoff wavelength of the short wavelength side with 50% transmittance and the cutoff wavelength of the long wavelength side with 50% transmittance is a cutoff wavelength amplitude greater than or equal to 100 nm.

2. The filter for a solid-state imaging element according to claim 1, wherein, The filter for the solid-state imaging element also has a microlens located on the incident surface side relative to the photoelectric conversion element. The barrier layer is located on the outer surface of the microlens. The refractive index of the barrier layer is lower than that of the microlens.

3. The filter for a solid-state imaging element according to claim 2, wherein, The infrared cut-off filter is a microlens containing an infrared absorber.

4. The filter for a solid-state imaging element according to any one of claims 1 to 3, wherein, The barrier layer has anti-reflective properties.

5. The filter for a solid-state imaging element according to any one of claims 1 to 3, wherein, It has a color filter located on the incident surface side relative to the photoelectric conversion element.

6. The filter for a solid-state imaging element according to claim 1, wherein, It has an infrared bandpass filter located on the incident surface side relative to the photoelectric conversion element. The infrared cut-off filter has a through-hole on the light incident side relative to the infrared bandpass filter.

7. The filter for a solid-state imaging element according to claim 1, wherein, The planarization layer also includes a planarization layer that fills the step difference of the base layer of the planarization layer. The barrier layer is located on the incident surface side of the light relative to the planarization layer.

8. A filter for a solid-state imaging element, comprising: The incident surface of light; and An infrared filter is located on the incident surface side relative to the photoelectric conversion element. The layer structure located on the incident surface side relative to the infrared filter simultaneously satisfies the following [B1] to [B3]: [B1] Oxygen permeability less than or equal to 5.0 cm⁻¹ 3 / m 2 / day / atm; [B2] Thickness greater than or equal to 10 nm and less than or equal to 500 nm; and [B3] The average transmittance in the visible light region is greater than or equal to 90%. The infrared filter is an infrared cutoff filter. The transmission spectrum of the infrared cut-off filter simultaneously satisfies the following [A1] to [A3]: [A1] In a wavelength band greater than or equal to 450 nm and less than or equal to 650 nm, the average transmittance is greater than or equal to 80%. [A2] It has the maximum absorption rate in the wavelength band of 800 nm or more and 1000 nm or less; as well as [A3] The difference between the cutoff wavelength of the short wavelength side with 50% transmittance and the cutoff wavelength of the long wavelength side with 50% transmittance is a cutoff wavelength amplitude greater than or equal to 100 nm.

9. A solid-state imaging element, comprising: Photoelectric conversion elements; and The filter for a solid-state imaging element according to any one of claims 1 to 8.

Images