Filter for solid-state imaging device and method for manufacturing same

Abstract

To provide a filter for a solid-state image sensor capable of suitably detecting light of a visible light region, a solid-state image sensor, and a manufacturing method for a solid-state image sensor.SOLUTION: A filter for a solid-state image sensor comprises: a first photoelectric conversion element; an infrared light pass filter lens positioned on a light incident surface side of the first photoelectric conversion element; a second photoelectric conversion element; a visible light filter positioned on a light incident surface side of the second photoelectric conversion element; and an infrared light cut filter lens positioned on the incident surface side with respect to the second photoelectric conversion element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filter for a solid-state imaging device and a method for manufacturing a solid-state imaging device. [Background technology]

[0002] Solid-state imaging devices such as CMOS image sensors and CCD image sensors include photoelectric conversion elements that convert light intensity into an electrical signal. Solid-state imaging devices are capable of detecting light corresponding to a plurality of colors, for example. Some solid-state imaging devices include color filters and photoelectric conversion elements for each color, and detect light of each color using the photoelectric conversion elements for each color (see, for example, Patent Document 1). Other solid-state imaging devices include organic photoelectric conversion elements and inorganic photoelectric conversion elements, and detect light of each color using the photoelectric conversion elements without using color filters (see, for example, Patent Document 2).

[0003] Some solid-state imaging devices include an infrared light cut filter on a photoelectric conversion element. In this type of solid-state imaging device, the infrared light absorbing dye in the infrared light cut filter absorbs infrared light, thereby cutting off infrared light that can be detected by each photoelectric conversion element. This improves the detection accuracy of visible light in each photoelectric conversion element. For example, some infrared light cut filters contain a cyanine dye, which is an infrared light absorbing dye (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-060176 [Patent Document 2] Japanese Patent Application Publication No. 2018-060910 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-219114 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, miniaturization of infrared cut filters is required as pixel sizes in solid-state imaging devices become smaller. Miniaturization of infrared cut filters is achieved by dry etching using a resist pattern formed on the infrared cut filter. In patterning an infrared cut filter using dry etching, a resist pattern is first formed on the infrared cut filter. The infrared cut filter is then etched using the resist pattern, and the resist pattern is then peeled off from the infrared cut filter. The stripping solution used to peel off the resist pattern from the infrared cut filter may leach a portion of the infrared-absorbing dye contained in the infrared cut filter out of the infrared cut filter upon contact with the infrared cut filter. This may result in a deterioration in the functionality of the solid-state imaging device. Furthermore, while infrared cut filters cut light in the infrared region, they also reduce the intensity of light in the visible region, resulting in a decrease in the light-receiving sensitivity of the solid-state imaging device.

[0006] An object of the present invention is to provide a filter for a solid-state imaging device, a solid-state imaging device, and a method for manufacturing a solid-state imaging device, which are capable of suitably detecting light in the visible light region. [Means for solving the problem]

[0007] One aspect of a filter for a solid-state imaging device for solving the above problem includes a first photoelectric conversion element, an infrared light pass filter lens located on the light incident surface side of the first photoelectric conversion element, a second photoelectric conversion element, a visible light filter located on the light incident surface side of the second photoelectric conversion element, and an infrared light cut filter lens located on the incident surface side of the second photoelectric conversion element, wherein the height of the infrared light cut filter lens is 1.2 μm or more and 1.4 μm or less, and the height of the infrared light pass filter lens is 1.5 μm or more, and the infrared light pass filter lens is an infrared light pass filter located on the light incident surface side of the first photoelectric conversion element. and a lens shape formed by a part of the infrared light pass filter. A filter for a solid-state imaging device comprising:

[0008] The height of the infrared light cut filter lens is 1.2 μm or more and 1.4 μm or less.

[0009] The infrared light pass filter lens and the infrared light cut filter lens may have a spherical shape.

[0010] The infrared light cut filter lens has a function of absorbing light with wavelengths of 250 to 350 nm.

[0011] Furthermore, one aspect of a method for manufacturing a solid-state imaging device for solving the above-described problems includes forming the infrared light pass filter lens and the infrared light cut filter lens by an etch-back process in which a resist pattern serving as a master mold, which has been deformed into a spherical lens shape, is transferred to the master mold using ultraviolet light that has a maximum emission spectrum intensity in the range of 250 to 350 nm. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress the degradation of the function of a solid-state imaging device in the visible light region caused by an infrared light cut filter. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an exploded perspective view showing the structure of a solid-state imaging device according to an embodiment of the present invention. [Figure 2] 5A to 5C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention. [Figure 3] 5A to 5C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention. [Figure 4] 5A to 5C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention. [Figure 5] 5A to 5C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to an embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing the structure of a solid-state imaging device according to a comparative example of the present invention. [Figure 7] 10A to 10C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to a comparative example of the present invention. [Figure 8] 10A to 10C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to a comparative example of the present invention. [Figure 9] 10A to 10C are process diagrams illustrating a method for manufacturing a solid-state imaging device according to a comparative example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Embodiments of a filter for a solid-state imaging device, a solid-state imaging device, and a method for manufacturing a solid-state imaging device according to the present invention will be described. The structure of the solid-state imaging device and the method for manufacturing the solid-state imaging device will be described below. In this embodiment, infrared light refers to light having a wavelength in the range of 700 nm to 1 mm, and near-infrared light refers to infrared light having a wavelength in the range of 700 nm to 1100 nm.

[0015] [Solid-state imaging device] First, the structure of a solid-state imaging device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is an exploded perspective view showing the structure of a solid-state imaging device according to an embodiment of the present invention. In Fig. 1, each layer in a part of the solid-state imaging device is shown separated.

[0016] 1, the solid-state imaging device 10 includes a solid-state imaging device filter 10F and a plurality of photoelectric conversion elements 11. The plurality of photoelectric conversion elements 11 include a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, a blue photoelectric conversion element 11B, and an infrared light photoelectric conversion element 11P. The red photoelectric conversion element 11R, the green photoelectric conversion element 11G, and the blue photoelectric conversion element 11B are examples of first photoelectric conversion elements, and the infrared light photoelectric conversion element 11P is an example of a second photoelectric conversion element.

[0017] The solid-state imaging device 10 includes a plurality of red photoelectric conversion elements 11R, a plurality of green photoelectric conversion elements 11G, a plurality of blue photoelectric conversion elements 11B, and a plurality of infrared photoelectric conversion elements 11P. The plurality of infrared photoelectric conversion elements 11P measure the intensity of infrared light. For convenience of illustration, FIG. 1 shows the smallest repeating unit of the photoelectric conversion elements 11 in the solid-state imaging device 10.

[0018] The solid-state imaging device filter 10F includes a visible light filter, an infrared light pass filter lens 12P, an infrared light cut filter lens 13, and an oxygen blocking layer 14, which will be described later.

[0019] The visible light filters are composed of a red filter 12R, a green filter 12G, and a blue filter 12B. The red filter 12R is located on the light incident side of the red photoelectric conversion element 11R. The green filter 12G is located on the light incident side of the green photoelectric conversion element 11G. The blue filter 12B is located on the light incident side of the blue photoelectric conversion element 11B. The thickness T12 of the visible light filters 12R, 12G, and 12B is, for example, not less than 0.5 μm and not more than 2.0 μm.

[0020] The pigments contained in the coloring compositions of the red filter 12R, green filter 12G, and blue filter 12B can be organic or inorganic, either alone or in combination. Pigments with high color development and heat resistance, particularly those with high thermal decomposition resistance, are preferred, and organic pigments are typically used. Usable pigments include organic pigments such as phthalocyanine, azo, anthraquinone, quinacridone, dioxazine, anthanthrone, indanthrone, perylene, thioindigo, isoindoline, quinophthalone, and diketopyrrolopyrrole. Specific examples of organic pigments that can be used in the coloring compositions of the present invention are listed below by color index number.

[0021] Examples of blue pigments used in blue coloring compositions for visible light filters include pigments such as CI Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64, and 81, with CI Pigment Blue 15:6 being preferred.

[0022] Examples of purple pigments include CI Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, and 50, and among these, CI Pigment Violet 23 is preferred.

[0023] Yellow pigments include CI 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, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 20, 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, and the like, and among these, CI Pigment Yellow 13, 150, and 185 are preferred.

[0024] The red coloring composition may contain, instead of a blue pigment, for example, CI Pigment 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, CI Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73, or the like, and, if necessary, for color matching, CI 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, 117, 118, 119, 1 20, 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.

[0025] The green colored composition is a composition obtained by using a green pigment such as CI Pigment Green 7, 10, 36, 37, 58, or 59 in place of the blue dye, and, if necessary, the above yellow pigment for color matching.

[0026] The infrared light pass filter lens 12P is located on the light incident side of the infrared light photoelectric conversion element 11P. The infrared light pass filter lens 12P blocks visible light that can be detected by the infrared light photoelectric conversion element 11P from reaching the infrared light photoelectric conversion element 11P. This improves the accuracy with which the infrared light photoelectric conversion element 11P detects infrared light. The infrared light that can be detected by the infrared light photoelectric conversion element 11P is near-infrared light, for example. The infrared light transmission function of the infrared light pass filter lens 12P can vary depending on the height T12 of the infrared light pass filter lens 12P. To fully utilize the infrared light transmission function of the infrared light pass filter lens 12P, the height T12 of the infrared light pass filter lens 12P is preferably 1.5 μm or more.

[0027] To efficiently capture light into the light-receiving section of the photoelectric conversion element 11, a technology has been proposed in which uniformly shaped microlenses are formed on the photoelectric conversion element. The microlenses focus light incident from the object for each pixel and guide it to the light-receiving section of the photoelectric conversion element. Focusing light with microlenses and directing it to the light-receiving section of the photoelectric conversion element increases the apparent aperture ratio of the light-receiving section, thereby improving the sensitivity of the solid-state imaging device. Furthermore, a large distance between adjacent microlenses at a 45-degree cross section can significantly affect crosstalk, a phenomenon in which light leaks into adjacent visible light filters through the gaps between the microlenses. Crosstalk refers to the phenomenon in which light that should be incident on a certain color is instead incident on an adjacent color due to the difference in refractive index between the pigments of each color. Due to crosstalk, light that should be incident on a color with a lower refractive index is lost by being incident on an adjacent color with a higher refractive index, reducing the amount of light reaching the light-receiving section and causing a decrease in sensitivity. Therefore, the infrared pass filter lens 12P of the present invention functions as a microlens in addition to its visible light blocking function. The shape may be, for example, a spherical shape, a parabolic shape, a sinusoidal shape, or a triangular pyramid. A spherical shape is preferable from the viewpoints of light collection efficiency and the ability to reduce the distance between adjacent microlenses at a 45-degree cross section. By using such an infrared light pass filter lens, the distance between the light incident portion of the lens and the photoelectric conversion element 11 is reduced compared to conventional solid-state imaging element structures (see FIG. 7), improving the light receiving sensitivity of the solid-state imaging element in the infrared region. Furthermore, the layer structure of the solid-state imaging element filter 10F can be simplified.

[0028] The constituent material of the infrared light pass filter lens 12P includes a black pigment or a black dye and a transparent resin. The black pigment may be a single pigment having a black color or a mixture of two or more pigments having a black color. Examples of the black dye include azo dyes, anthraquinone dyes, azine dyes, quinoline dyes, perinone dyes, perylene dyes, and methine dyes. Examples of the transparent resin include acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins. The constituent material of the infrared light pass filter lens 12P may also contain inorganic oxide particles to adjust the refractive index. Examples of inorganic oxides include aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide. The infrared light pass filter lens 12P may also contain additives that provide other functions, such as light stabilizers, antioxidants, heat stabilizers, and antistatic agents.

[0029] The infrared cut filter lenses 13 (13R, 13G, 13B) are positioned on the light incident side of the visible light filters 12R, 12G, and 12B. When viewed from a perspective facing the plane on which the infrared cut filter lenses 13 extend, the infrared cut filter lenses 13 are positioned above the red filter 12R, the green filter 12G, and the blue filter 12B. In addition to their infrared cut function, the infrared cut filter lenses 13 function as microlenses, similar to the infrared pass filter lenses 12. Examples of their shapes include spherical, parabolic, sinusoidal, and triangular pyramidal shapes. A spherical shape is preferred from the viewpoints of light collection efficiency and the ability to reduce the 45-degree cross-sectional distance between adjacent microlenses. By using such infrared cut filter lenses, the distance between the light incident portion of the lens and the photoelectric conversion element 11 is reduced compared to conventional solid-state imaging element structures (see FIG. 7), improving the light receiving sensitivity of the solid-state imaging element in the visible range. Furthermore, the layer structure of the filter 10F for solid-state imaging devices can be simplified.

[0030] The infrared light absorbing dye for forming the infrared light cut filter lens 13 may be at least one selected from, for example, anthraquinone dyes, cyanine dyes, phthalocyanine dyes, dithiol dyes, diimonium dyes, squarylium dyes, and croconium dyes. Among these dyes, cyanine dyes are preferred. Cyanine dyes have a maximum infrared light absorption rate at any wavelength included in the near-infrared range. Therefore, the infrared light cut filter lens 13 can reliably absorb near-infrared light incident on the infrared light cut filter lens 13. This allows the infrared light cut filter lens 13 to adequately cut near-infrared light that can be detected by the photoelectric conversion elements 11 for each color.

[0031] The transparent resin used to form the infrared light cut filter lens 13 may be at least one selected from, for example, acrylic resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, and norbornene resins. Among these resins, the transparent resin is preferably an acrylic resin. By using an acrylic resin, a flat, uniform infrared light cut precursor layer 23 can be formed without being affected by the step TP (see FIG. 2) between the infrared light pass filter lens 12P and the visible light filters 12R, 12G, and 12B. In an environment irradiated with sunlight, the infrared absorbing dye comes into contact with oxygen and water in the air, which changes the transmission spectrum in the near-infrared band. In other words, the infrared light cut filter lens 13 comes into contact with an oxidizing source in an environment irradiated with sunlight, thereby reducing its near-infrared light cut performance. In this regard, the light resistance of the infrared cut filter lens 13 can be improved by providing an oxygen barrier layer 14 (described later) on the incident surface side of the infrared cut filter lens 13. In addition, the infrared-absorbing dye may alter the transmission spectrum of the infrared cut filter lens 13 in the near-infrared band due to ultraviolet light generated during the formation process of the infrared cut filter lens 13, for example, when a plasma device is used, particularly ultraviolet light in the 250 to 350 nm range. Therefore, in the present invention, the infrared cut filter lens 13 is characterized by having the function of absorbing wavelengths of 250 to 350 nm. While any method can be used to absorb wavelengths of 250 to 350 nm, adding an ultraviolet absorber is one method. Usable materials include salicylates, benzotriazole compounds, benzophenone compounds, salicylic acid compounds, coumarin compounds, substituted acrylonitriles, and triazines, and these may be used alone or in combination.

[0032] The oxygen-blocking layer 14 is located on the light incident side of the infrared cut filter lens 13 and the infrared pass filter lens 12P. The oxygen-blocking layer 14 is a layer common to the red filter 12R, the green filter 12G, the blue filter 12B, and the infrared pass filter lens 12P. The oxygen-blocking layer 14 prevents an oxidizing source from passing through the infrared cut filter lens 13. Examples of the oxidizing source include oxygen and water.

[0033] The oxygen barrier layer 14 has an oxygen permeability of, for example, 5.0 cc / m 2 The oxygen permeability of the oxygen barrier layer 14 is preferably 5.0 cc / m or less. This oxygen permeability is a value measured by a method conforming to JIS K7126:2006. 2 / day / atom or less, the oxygen blocking layer 14 prevents the oxidizing source from reaching the infrared cut filter lens 13. Therefore, the infrared cut filter lens 13 is less likely to be oxidized by the oxidizing source. This makes it possible to improve the light resistance of the infrared cut filter lens 13.

[0034] The height of the infrared light cut filter lens 13 in the stacking direction is preferably 1.2 to 1.4 μm to ensure infrared light cutoff performance and to ensure the characteristics of the solid-state imaging device in the visible range. If the height of the infrared light cut filter lens 13 is in the range of 1.2 to 1.4 μm, a near-infrared light cutoff rate of 90% or more can be ensured, for example, in the wavelength range of 840 to 940 nm. If the height is less than 1.2 μm, the near-infrared light cutoff rate will be less than 90%, and the detection accuracy of visible light will not be improved. Here, the near-infrared light cutoff rate is calculated as the average rate of change in the light receiving sensitivity of the solid-state imaging device in the infrared range between with and without an infrared light cutoff filter. On the other hand, if the height exceeds 1.4 μm, the distance to the photoelectric conversion element will be increased, resulting in a decrease in light receiving sensitivity in the visible light range.

[0035] [Method of manufacturing a solid-state imaging device] Next, a method for manufacturing a solid-state imaging device including a filter for a solid-state imaging device will be described.

[0036] The method for manufacturing a filter for a solid-state imaging device according to this embodiment includes at least the steps of forming a visible light filter and an infrared light pass filter, forming an infrared light cut precursor layer, and forming an infrared light pass filter lens and an infrared light cut filter lens.

[0037] Hereinafter, the method for manufacturing a filter for a solid-state imaging device and the method for manufacturing a solid-state imaging device according to this embodiment will be described in more detail with reference to Figures 2 to 5. Figures 2 to 5 are process diagrams for explaining the method for manufacturing a solid-state imaging device according to this embodiment of the present invention. Note that Figures 2 to 5 schematically show a cross section of the solid-state imaging device cut along the direction in which the layers constituting the solid-state imaging device are stacked, i.e., the AA' cross section in Figure 1.

[0038] As shown in Fig. 2, in the method for manufacturing a filter for a solid-state imaging device according to this embodiment, first, a semiconductor substrate 21 is prepared. A plurality of photoelectric conversion elements 11 are two-dimensionally arranged on the semiconductor substrate 21, such that one photoelectric conversion element 11 corresponds to one pixel. Note that Figs. 2 to 5 illustrate two red photoelectric conversion elements 11R and three infrared photoelectric conversion elements 11P. The material forming the semiconductor substrate 21 may be, for example, Si, an oxide such as SiO2, a nitride such as SiN, or a mixture thereof.

[0039] As shown in FIG. 2, a red filter 12R is formed on the semiconductor substrate 21 at a position corresponding to the red photoelectric conversion element 11R of the semiconductor substrate 21, and an infrared light pass filter 22P is formed at a position corresponding to the infrared light photoelectric conversion element 11P. The infrared light pass filter 22P is formed so that its thickness is greater than that of the red filter 12R. The step formed in this manner between the surface of the infrared light pass filter 22P and the surface of the red filter 12R is indicated as a "step TP" in FIG. 2. Note that FIG. 2 omits illustrations of the blue photoelectric conversion element 11B, the blue filter 12B corresponding to the blue photoelectric conversion element 11B, the green photoelectric conversion element 11G, and the green filter 12G corresponding to the green photoelectric conversion element 11G.

[0040] The red filter 12R is formed, for example, by forming a coating film containing a red photosensitive resin and patterning the coating film using a photolithography method. The coating film containing the red photosensitive resin is formed, for example, by applying a coating liquid containing the red photosensitive resin and drying the coating film. The red filter 12R is formed, for example, by exposing the coating film containing the red photosensitive resin to an area corresponding to the red filter 12R and developing it. On the semiconductor substrate 21, the green filter 12G, the blue filter 12B, and the infrared light pass filter 22P are formed in the same manner as the red filter 12R.

[0041] The visible light filters including the red filter 12R may be formed before the infrared light pass filter 22P, or the infrared light pass filter 22P may be formed before the visible light filter. Since the infrared light pass filter 22P is formed to be thicker than the visible light filter, it is preferable from a manufacturing standpoint to form the visible light filter before the infrared light pass filter 22P.

[0042] In this embodiment, the film thicknesses (heights) of the green filter 12G, the red filter 12R, and the blue filter 12B may be different from one another or may be the same.

[0043] Next, as shown in FIG. 3, an infrared-cutting precursor layer 23 is formed on the visible light filter and infrared light pass filter 22P. When forming the infrared-cutting precursor layer 23, first, a coating liquid containing an infrared-absorbing dye, a transparent resin, an ultraviolet absorber, and an organic solvent is applied to the visible light filter and infrared light pass filter 22P, and the coating film is dried. Next, the dried coating film is cured by heating. In this way, the infrared-cutting precursor layer 23 is formed.

[0044] Next, as shown in FIG. 4, a plurality of infrared pass filter lenses 12P and infrared cut filter lenses 13 are formed. The plurality of infrared pass filter lenses 12P are formed from portions of the infrared pass filters 22P, and the infrared cut filter lenses 13 are formed at positions overlapping the respective visible light filters 12R, 12G, and 12B when viewed from a viewpoint opposite to the plane on which the infrared cut precursor layer 23 extends. The infrared pass filter lenses 12P and the infrared cut filter lenses 13 are formed using an etch-back method. In the etch-back method, a resist pattern serving as a master mold having a spherical lens shape, which is a shape in which multiple hemispheres are arranged, is first formed on the infrared cut precursor layer 23. Then, the master resist pattern is dry-etched to transfer the spherical lens shape of the resist pattern to the infrared cut precursor layer 23 and the infrared pass filters 22P, thereby forming a plurality of infrared pass filter lenses 12P and infrared cut filter lenses 13. Here, the dry etching of the resist pattern may be, for example, plasma etching. Gases containing at least one selected from the group consisting of fluorine, oxygen, hydrogen, sulfur, carbon, bromine, chlorine, nitrogen, argon, helium, xenon, and krypton can be used. Fluorine-based gases are particularly preferred, including at least one selected from the group consisting of CF4, C2F6, C3F8, C2F4, C4F8, C4F6, C5F8, and CHF3. Among these, from the perspective of forming the desired spherical lens, the fluorine-based gas is preferably at least one selected from the group consisting of C2F6, C3F8, and C4F8. During dry etching of the infrared-cut precursor layer 23, a bias can be applied to the infrared-cut precursor layer 23. The above-mentioned etch-back method does not strip the resist pattern; that is, it does not use a resist pattern stripper, which can degrade the spectral characteristics of the infrared-cut filter. As a result, the degradation of the function of the solid-state imaging device 10 caused by partial elution of the infrared light absorbing dye contained in the infrared light cut filter lens 13 is suppressed.

[0045] Next, as shown in FIG. 5 , an oxygen-blocking layer 14 is formed to cover the surfaces of the infrared cut filter lens 13 and the infrared pass filter lens 12P when viewed from a perspective opposite the plane on which the semiconductor substrate 21 extends. This allows the solid-state imaging device 10 according to this embodiment to be obtained. The oxygen-blocking layer 14 is formed by a vapor-phase film-forming method such as sputtering, CVD, or ion plating, or a liquid-phase film-forming method such as coating. The oxygen-blocking layer 14 made of silicon oxide may be formed, for example, by sputtering using a silicon oxide target. Alternatively, the oxygen-blocking layer 14 may be formed, for example, by CVD using silane and oxygen. Alternatively, the oxygen-blocking layer 14 made of silicon oxide may be formed by applying a coating liquid containing polysilazane, modifying the coating, and then drying the resulting coating.

[0046] The layer structure of the oxygen-blocking layer 14 may be a single layer structure made of a single compound, a laminated structure of layers made of a single compound, or a laminated structure of layers made of different compounds.

[0047] This makes it possible to form a plurality of solid-state imaging devices 10, which have been described above with reference to FIG.

[0048] [Example] A manufacturing example of a solid-state imaging device corresponding to the embodiment will be described below. Note that in the manufacturing example described below, a manufacturing example of a solid-state imaging device 10 will be described in which the height T12 of the infrared light pass filter lens 12P is greater than the heights of the visible light filters 12R, 12G, and 12B.

[0049] A green resist layer containing a green pigment, a photosensitive curable resin, and a thermosetting resin was spin-coated at 1000 rpm on a semiconductor substrate 21 with multiple photoelectric conversion elements 11 arranged two-dimensionally. The green pigment was CIPG58 in color index. The green pigment concentration in the green resist was set to 70% by mass. Next, the green resist layer was selectively exposed using a green mask, and the exposed green resist layer was developed to form a green filter 12G pattern. The green filter 12G pattern was then cured by heating at 230°C for 6 minutes using a hot plate. This resulted in a green filter having a thickness of 500 nm.

[0050] Next, a blue resist layer containing a pigment, a photosensitive curable resin, and a thermosetting resin was spin-coated at 1000 rpm on the green filter 12G and on the portion of the semiconductor substrate 21 not covered by the green filter 12G. The pigments used were CIPB156 and CIPV23 in the color index. The blue pigment concentration in the blue resist was set to 50% by mass. Next, the blue resist layer was selectively exposed by photolithography using a blue mask, and the exposed blue resist layer was developed to form a blue filter 12B pattern. The blue filter 12B pattern was then cured by heating at 230°C for 6 minutes using a hot plate. This resulted in a blue filter 12B with a thickness of 600 nm. The blue filter 12B was formed at a position on the surface of the semiconductor substrate 21 different from the position where the green filter 12G was formed.

[0051] Next, a red resist containing a pigment, a photosensitive curable resin, and a thermosetting resin was spin-coated at 1000 rpm on the green filter 12G, the blue filter 12B, and the portions of the semiconductor substrate 21 not covered by these filters to form a red resist layer. The pigments used were CIPR254 and CIPY139 in the Color Index. The pigment concentration in the red resist was set to 60% by mass. Next, the red resist layer was selectively exposed using a red mask, and the exposed red resist layer was developed to form a red filter 12R pattern. The red filter 12R pattern was then cured by heating it at 230°C for 6 minutes using a hot plate. This resulted in a red filter 12R with a thickness of 600 nm. The red filter 12R was formed at a position on the surface of the semiconductor substrate 21 different from the positions where the blue filter 12B and the green filter 12G were formed.

[0052] Next, a photosensitive infrared light path resist containing blue, purple, and yellow pigments was applied to the visible light filters 12R, 12G, and 12B and to the portions of the semiconductor substrate 21 not covered by the visible light filters. This formed an infrared light path resist layer. CIPB15:6 (Color Index) was used for the blue pigment, CIPV23 (Color Index) was used for the purple pigment, and CIPY139 (Color Index) was used for the yellow pigment. The pigment concentration in the infrared light path resist was set to 78% by mass.

[0053] Next, the infrared light pass resist layer was selectively exposed using an infrared light pass mask, and the exposed infrared light pass resist layer was developed to form an infrared light pass filter 22P pattern. The infrared light pass filter 22P pattern was then cured by heating at 230°C for 6 minutes using a hot plate. This resulted in an infrared light pass filter 22P with a thickness of 1900 nm. The infrared light pass filter 22P was formed at a position on the surface of the semiconductor substrate 21 different from the positions where the visible light filters 12R, 12G, and 12B were formed. The infrared light pass filter 22P had a maximum transmittance of 4.8% for light having a wavelength of 400 nm to 650 nm, and a maximum transmittance of 8.6% for light having a wavelength of 650 nm to 730 nm. The infrared light pass filter 22P also had a minimum transmittance of 92.1% for light having a wavelength of 800 nm to 1000 nm.

[0054] Next, a coating solution containing an infrared-absorbing dye, an ultraviolet absorber, and a thermosetting resin was spin-coated at 600 rpm onto the visible light filters 12R, 12G, and 12B and the infrared light pass filter 22P to form a coating film. The coating film was then cured by heating at 200°C for 20 minutes using a hot plate. This resulted in an infrared light-cutting precursor layer 23 having a thickness of 1600 nm being formed on the visible light filters 12R, 12G, and 12B and the infrared light pass filter 22P. The infrared light-cutting precursor layer 23 had a transmittance of 8% for light having a wavelength around 940 nm.

[0055] Next, a resist pattern serving as a master mold having a spherical lens shape, which is a shape in which multiple hemispheres are arranged, was formed on the infrared-cut precursor layer 23. The master resist pattern was then dry-etched to form the infrared-cut filter lens 13 and the infrared-pass filter lens 12P. An ICP-type dry etching device was used for this process. The etching gas used was fluorine-based gas C4F8, and etching was performed by applying a bias to the etching target. This resulted in the formation of an infrared-cut filter lens 13 with a height of 1.2 μm. The height of the infrared-pass filter lens 13 was 1.7 μm. When the emission intensity during plasma etching using C4F8 was confirmed, an emission intensity with a maximum value near 260 nm was obtained.

[0056] Next, an oxygen blocking layer 14 made of SiO2 and having a thickness of 100 nm was formed on the surfaces of the infrared cut filter lens 13 and the infrared pass filter lens 12P by plasma CVD, thereby obtaining the solid-state imaging device 10 according to this example.

[0057] [Comparative Example] Fig. 6 is a cross-sectional view showing the structure of a solid-state imaging device according to a comparative example of the present invention. Fig. 6 shows the structure of the solid-state imaging device filter and solid-state imaging device 100 for comparison. In this configuration, a microlens 250 is formed on an infrared light cut filter 240 and an infrared light pass filter 220P.

[0058] 7 to 9 are process diagrams for explaining a method for manufacturing a solid-state imaging device according to a comparative example of the present invention. The method for manufacturing a solid-state imaging device filter according to the comparative example will be explained below with reference to Figs. 7 to 9, focusing on differences from the example. The rest of the method is the same as the example.

[0059] As shown in FIG. 7 , a resist pattern 260 was formed only on the visible light filter 120R on the infrared light pass filter 220P and the infrared light cut precursor layer 230. To form the resist pattern 260, a photoresist layer was first formed to entirely cover the infrared light pass filter 220P and the infrared light cut precursor layer 230. A positive resist was used as the material for forming the photoresist layer. A portion of the photoresist layer was then exposed using a photomask. The photoresist layer was then developed. A resist pattern 260 having an opening overlapping the infrared light pass filter 220P was formed. Next, the infrared light cut precursor layer 230 was patterned by dry etching using the resist pattern 260. An ICP dry etching system was used for this process. A mixed gas containing argon gas and oxygen gas was used as the etching gas, and a bias was applied to the etching target to perform anisotropic etching on the infrared light cut precursor layer 230. As a result, an infrared light cut filter 240 having a thickness of 1200 nm was formed.

[0060] 8, the resist pattern 260 was stripped from the infrared light cut precursor layer 230 by a dipping method using a stripper. The stripper used was a mixture of N-methylpyrrolidone and dimethyl sulfoxide, which can dissolve the resist pattern 260.

[0061] 9, a plurality of microlenses 250 having a height of 500 nm were formed by etching back on the infrared light pass filter 220P and the infrared light cut filter 240. Furthermore, an oxygen blocking film 140 was formed in the same manner as in the example, and the solid-state imaging element 100 according to this comparative example, as shown in FIG.

[0062] Thus, the solid-state imaging element filter of this embodiment, which has an infrared light-cutting filter lens 13 with a height of 1.2 μm, can maintain sufficient infrared light-cutting performance, and the light receiving sensitivity of the solid-state imaging element in the visible range was approximately 1.2 times higher for each pixel (each color) compared to the solid-state imaging element filter described in the comparative example.

[0063] Furthermore, the method for manufacturing a solid-state imaging device filter according to this embodiment enables the formation of a pixel pitch of 1.0 μm, and does not require a stripping solution to strip the resist pattern when forming the infrared cut filter. As a result, the elution of the infrared light absorbing dye contained in the infrared cut filter during formation of the infrared cut filter is suppressed, and the deterioration of the function of the solid-state imaging device can be suppressed. [Explanation of symbols]

[0064] 10...Solid-state image sensor 10F...Solid-state image sensor filter 11...Photoelectric conversion element 12B...Blue filter 12G...Green filter 12P...Infrared light pass filter lens 12R...Red filter 13...Infrared cut filter lens 14...Oxygen barrier layer 21...Semiconductor substrate 22P...Infrared light pass filter 23...Infrared light blocking precursor layer 24...Infrared cut filter 25...Microlens 26...Resist pattern

Claims

1. a first photoelectric conversion element; and an infrared light pass filter lens located on the light incident surface side of the first photoelectric conversion element; a second photoelectric conversion element; and a visible light filter located on the light incident surface side of the second photoelectric conversion element; an infrared light cut filter lens located on the incident surface side of the second photoelectric conversion element, the height of the infrared light cut filter lens is 1.2 μm or more and 1.4 μm or less; The height of the infrared light pass filter lens is 1.5 μm or more, The infrared light pass filter lens is a filter for a solid-state imaging element, which comprises an infrared light pass filter located on the light incident surface side of the first photoelectric conversion element and a lens shape formed by a part of the infrared light pass filter.

2. a first photoelectric conversion element; and an infrared light pass filter lens located on the light incident surface side of the first photoelectric conversion element; a second photoelectric conversion element; and a visible light filter located on the light incident surface side of the second photoelectric conversion element; an infrared light cut filter lens located on the incident surface side of the second photoelectric conversion element, The infrared light pass filter lens is a filter for solid-state imaging elements, which comprises an infrared light pass filter located on the light incident surface side of the first photoelectric conversion element and a lens shape formed by a part of the infrared light pass filter, and contains particles of an inorganic compound selected from aluminum oxide, silicon oxide, and zirconium oxide.

3. 3. A filter for a solid-state imaging device according to claim 1, wherein the infrared-pass filter lens and the infrared-cut filter lens have a spherical shape.

4. 3. The filter for a solid-state imaging device according to claim 1, wherein the infrared light cut filter lens has a function of absorbing light having a wavelength of 250 to 350 nm.

5. A method for manufacturing a solid-state imaging device comprising the filter for a solid-state imaging device according to any one of claims 1 to 4, comprising the steps of: The infrared light pass filter lens and the infrared light cut filter lens are formed by an etch-back process in which a resist pattern, which serves as a master mold and has been deformed into a spherical lens shape, is transferred onto the master mold using ultraviolet light that has a maximum emission spectrum intensity in the range of 250 to 350 nm.

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