JP2010021427A - Solid-state imaging element and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging element that is prevented from decreasing sensitivity with the miniaturization of a cell. <P>SOLUTION: The solid-state imaging element has a plurality of pixels each comprising a microlenses 1 and a light-receiving element 6 which receives light converged by the microlens 1, and the pixels each have a transparent flattening film 3 provided between the microlens 1 and light-receiving element 6 and made of a dielectric material, and a plurality of particulates 9 of 5 to 500 nm in particle size provided in the transparent flattening film 3 in an array from the microlens 1 to the light-receiving element 6 and made of a negative dielectric material having a negative dielectric constant. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device used for a digital camera or the like and a manufacturing method thereof.

  In recent years, with the popularization of digital cameras and camera-equipped mobile phones, the market for solid-state imaging devices has significantly increased. While a wide variety of application developments are being implemented, the technological trends range from pixel size miniaturization, wide dynamic range, and high sensitivity. In particular, miniaturization of the pixel size is an indispensable technique for obtaining a high-resolution / high-definition image.

  In a solid-state imaging device such as a CCD (Charge Coupled Device) image sensor or a MOS (Metal Oxide Semiconductor) image sensor, a plurality of semiconductor integrated circuits (pixels) each having a light receiving element are two-dimensionally arranged to Optical signals are converted into electrical signals. Since the sensitivity of a solid-state imaging device is defined by the magnitude of the output current of the light receiving element with respect to the amount of incident light, it is an important factor for improving sensitivity to reliably introduce incident light into the light receiving element. . For this reason, a spherical lens called a microlens is formed in most solid-state imaging devices such as a CCD image sensor and a MOS image sensor.

  FIG. 11 is a diagram illustrating an example of a basic structure of a conventional general pixel.

  As shown in FIG. 11, a microlens 1 is formed on the top of the pixel, and a color filter 2 and a light-shielding film 4 for color-separating incident light are disposed below the microlens 1. Furthermore, a Si substrate 7 on which a light receiving element 6 for converting incident light into an electric signal is formed is disposed at the bottom of the pixel. By forming the condensing element (microlens 1) on the top of the solid-state imaging element, the incident light is converged by the microlens 1 and efficiently passes through the light shielding film 4 and the wiring layer 5 and enters the light receiving element 6. To do.

As a technique for efficiently guiding incident light to the light receiving element, there is a solid-state imaging element described in Patent Document 1. In this solid-state imaging device, a high refractive index optical waveguide made of silicon nitride or the like is formed above the light receiving device.
JP 2007-173258 A

  However, with the miniaturization of the pixel size, the light collection efficiency of the microlens 1 is reduced, and the sensitivity of the solid-state imaging device is significantly reduced. FIG. 12 is a diagram showing a light propagation profile of incident light 10 in a conventional solid-state imaging device. At this time, since the pixel size is 0.45 μm square and the opening of the light shielding film 4 is 0.25 μm square, the opening of the light shielding film 4 is about half the wavelength of the incident light 10. Therefore, as shown in FIG. 12, the incident light 10 cannot pass through the opening, and the incident light 10 does not enter the light receiving element 6.

  FIG. 13 is a diagram showing the relationship between the aspect ratio / sensitivity (sensitivity when light is vertically incident on the pixel) and the pixel size (cell size). Here, the aspect ratio is a value obtained by dividing the distance between the microlens 1 and the light receiving element 6 by the cell size. If the cell size is about 6 μm square, the aspect ratio is approximately 1. As the cell size decreases, the aspect ratio increases. When the cell size is smaller than 2 μm square, the aspect ratio becomes 3 or more. At this time, as shown in FIG. 13, the sensitivity rapidly decreases with a decrease in cell size. When the cell size is 1 μm square or less, the incident light hardly reaches the light receiving element 6 and the sensitivity becomes almost zero.

  According to the technique described in Patent Document 1, it is considered that the problem shown in FIGS. 12 and 13 can be solved by increasing the refractive index of the optical waveguide. Since the refractive index difference with the material around the waveguide becomes larger, light does not enter the optical waveguide due to reflection. Therefore, this technique cannot cope with the problems shown in FIGS.

  In view of the above problems, an object of the present invention is to provide a solid-state imaging device capable of preventing a decrease in sensitivity associated with a reduction in cell size and a method for manufacturing the same.

  The reason why the incident light cannot pass through the opening of the light shielding film is that the wavelength of the light is larger than the diffraction limit. In other words, if the waveguide mode of the incident light can be changed so that the incident light can pass through a region smaller than the diffraction limit, the sensitivity of the solid-state imaging device is improved. In order to realize light propagation in a region smaller than the diffraction limit of light, it is necessary to use a plasmonic waveguide. A plasmonic waveguide is an optical waveguide that uses surface plasmon polaritons that exist at the interface between a negative dielectric and a dielectric.

  For example, in JP-A-2005-351194, light is guided by generating surface charges that circulate around the surface of a metal microsphere and propagating plasmon polaritons to the second and third microspheres. . In Japanese Patent Application Laid-Open No. 2006-023410, plasmon light is collected by a plasmon lens structure arranged in a semicircular shape on a metal film, thereby realizing a more efficient optical waveguide. Both techniques are general two-dimensional waveguides applied to optical integrated circuits. In the future, in order to realize a solid-state imaging device having a cell size of 1 μm square or less, development of a device having a plasmonic waveguide is indispensable.

  Based on the above findings, the present inventors have scrutinized the application of the plasmonic waveguide to the solid-state imaging device, and have reached the present invention.

  In order to solve the above problems, a solid-state imaging device according to the present invention is a solid-state imaging device including a plurality of pixels each having a light collecting element and a light receiving element that receives light collected by the light collecting element. The pixel is provided in the dielectric material in the vicinity of the dielectric material provided between the light collecting element and the light receiving element, and continuously in the direction from the light collecting element to the light receiving element, And a plurality of fine particles having a particle size of 5 nm to 500 nm made of a negative dielectric material having a negative dielectric constant. As a result, a plasmonic waveguide made of fine particles is constructed in the solid-state imaging device, so that the incident light is guided to the light receiving element even when the wavelength of the incident light becomes larger than the opening of the light shielding film as the cell size decreases. It is possible to prevent a decrease in sensitivity due to cell size miniaturization.

  Here, the plurality of pixels may include a pixel having fine particles made of a first type material and a pixel having fine particles made of a second type material. Thereby, color separation of incident light by the plasmonic waveguide becomes possible, and color reproducibility is improved. Further, since it is not necessary to provide a color filter, the size can be reduced.

  The plurality of pixels include a pixel having fine particles composed of at least one of gold, silver, copper, aluminum, tantalum, chromium, and iron chromium oxide, cobalt titanium oxide, nickel titanium zinc oxide, and cobalt. A pixel having fine particles composed of at least one of zinc oxide and a pixel having fine particles composed of at least one of cobalt aluminum oxide and cobalt chrome oxide may be included. This eliminates the need to use unique metal and oxide materials, and can reduce production costs.

  One pixel may have two or more kinds of fine particles made of different materials. As a result, the manufacturing process becomes easy, and the production cost can be suppressed.

  In the plurality of fine particles arranged in a row in one pixel, the first fine particles arranged on the light collecting element side have a larger particle size than the second fine particles arranged on the light receiving element side. You may have. This facilitates scattering of incident light with fine particles having a large particle size, increasing the plasmon conversion efficiency and improving the sensitivity.

  The condensing element may include an effective refractive index distribution generated in a light transmission film having a concentric structure divided by a line width equal to or shorter than a wavelength of light to be collected. As a result, light incident at a high angle is guided to the light receiving element by the condensing element, and the oblique incidence characteristics of the light are improved, so that the sensitivity is improved.

  According to the solid-state imaging device of the present invention, light propagation in a region smaller than the diffraction limit of incident light within the device is possible, and even when the cell size is miniaturized, incident light can be guided to the light receiving device. A high-sensitivity and ultrafine cell-size solid-state imaging device can be realized.

  Hereinafter, a solid-state imaging device according to an embodiment of the present invention will be specifically described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a solid-state imaging device of full HD (full high vision) specification (2 million pixels) according to the present embodiment.

In this solid-state imaging device, the cell size is 0.45 μm square. The solid-state imaging device, a microlens 1 formed of a resin, and the color filter 2, a transparent flattening film 3 composed of SiO _2, and the light-shielding film 4, the wiring layer 5, the light-receiving element (Si photodiode ) 6 and the Si substrate 7. The transparent planarizing film 3, the light shielding film 4, the wiring layer 5, the light receiving element 6 and the Si substrate 7 constitute a semiconductor integrated circuit 8.

  The microlens 1 is a condensing element that collects incident light on the solid-state imaging element. The light receiving element 6 receives light collected by the microlens 1 and performs photoelectric conversion.

A transparent flattening film 3 made of a dielectric material is provided between the microlens 1 (color filter 2) and the light receiving element 6. In the transparent flattening film 3, cubic fine particles 9 having a particle size (particle size) of 0.1 μm are arranged in a line from the microlens 1 toward the light receiving element 6 and spaced by 0.2 μm in the Y direction. Are arranged periodically. In this way, by arranging the fine particles 9 that are negative dielectric material (material having a negative dielectric constant) in series in the dielectric material SiO ₂ (transparent flattening film 3), the fine particles 9 are It functions as a 0-dimensional plasmonic waveguide. In FIG. 1, cubic fine particles 9 are shown, but spherical or polygonal fine particles may be used.

  The fine particles 9 are metal or metal oxide such as gold, silver, copper, aluminum, tantalum, chromium, iron chromium oxide, cobalt titanium nickel zinc oxide, cobalt titanium oxide, nickel titanium zinc oxide, cobalt zinc oxide. And at least one of cobalt aluminum oxide and cobalt chromium oxide.

  FIG. 2 shows a light propagation profile of the solid-state imaging device having the above structure.

  Incident light 10 to the solid-state imaging device is collected by the microlens 1, passes through the light shielding film 4 and the wiring layer 5 through the fine particles 9, and reaches the light receiving device 6. The incident light 10 is scattered by the fine particles 9 to generate plasmon light, and the generated plasmon light reaches the light receiving element 6 while propagating through the adjacent fine particles 9. Basically, localized surface plasmons of fine particles made of a negative dielectric material are localized at one point and do not transfer energy as they are. However, by arranging the fine particles in series at intervals smaller than the wavelength of light, an interaction occurs between the adjacent fine particles, and the energy of the localized surface plasmon moves to the adjacent fine particles. As a result, the light energy is guided according to the arrangement of the fine particles. Since the light intensity distribution strongly depends on the particle size of the fine particles, a nanometer-order optical waveguide can be realized. In the solid-state imaging device of FIG. 1, plasmon light generated by light scattering by fine particles is used. However, if plasmon light is excited more efficiently by providing a prism arranged as a condensing element, for example. The sensitivity of the solid-state image sensor is improved.

  FIG. 3A to FIG. 3G are diagrams showing a manufacturing process of the plasmonic waveguide according to the present embodiment. The plasmonic waveguide structure is formed by a plurality of photolithography and etching.

  First, using a normal semiconductor process, a transparent planarizing film 3, a light shielding film 4 and a wiring layer 5 are formed on a Si substrate 7 on which a light receiving element 6 is formed, and a semiconductor integrated circuit 8 (in FIG. Details are not shown). The cell size of one pixel is 0.45 μm square, and the size of one light receiving element 6 is 0.25 μm square.

  Next, a resist 11 is applied to the surface of the transparent planarizing film 3 (FIG. 3A). Thereafter, the resist 11 is patterned by photolithography 12 (FIG. 3B).

  Next, after development, dry etching 13 is performed on the transparent planarizing film 3 using the resist 11 as a mask (FIG. 3C). Thereafter, gold 15 is deposited by gold deposition 14 on the bottom of the hole of the transparent planarizing film 3 formed by dry etching 13 (FIG. 3D).

Next, a SiO ₂ film as a part of the transparent flattening film 3 is formed on the gold 15 using a CVD apparatus (FIG. 3E).

Finally, after a gold / SiO ₂ film is formed in a multilayer shape, the surface is flattened by CMP (Chemical Mechanical Polishing) 16 (FIG. 3F and FIG. 3G). As a result, in the transparent flattening film 3 provided between the microlens 1 and the light receiving element 6, the negative dielectric material is arranged in the form of being adjacent and continuously arranged in the direction from the microlens 1 to the light receiving element 6. A plurality of fine particles 9 having a particle size of 5 nm to 500 nm are formed.

  As described above, according to the solid-state imaging device of the present embodiment, the zero-dimensional plasmonic waveguide that guides the incident light to the light receiving element 6 can be formed in the pixel, so that the incident light exceeds the light diffraction limit. Thus, it is possible to transmit a region narrower than the wavelength. As a result, even if the cell size is reduced to 1 μm square or less, incident light can pass through the light shielding film, and high sensitivity can be maintained.

(Embodiment 2)
FIG. 4 is a cross-sectional view of a solid-state imaging device of full HD specification (2 million pixels) according to the present embodiment.

  In this solid-state imaging device, the cell size is 0.45 μm square. The solid-state imaging device includes a microlens 1, a color filter 2, a transparent flattening film 3, a light shielding film 4, a wiring layer 5, a light receiving element 6, and a Si substrate 7. The transparent planarizing film 3, the light shielding film 4, the wiring layer 5, the light receiving element 6 and the Si substrate 7 constitute a semiconductor integrated circuit 8.

Between the microlens 1 and the light receiving element 6, spherical fine particles 17, 18 or 19 are arranged in a row from the microlens 1 toward the light receiving element 6 and periodically arranged at intervals of 0.2 μm in the Y direction. is doing. The materials of the main particles 17, 18 and 19 constituting the plasmonic waveguide are different in adjacent pixels. That is, in the pixel of the red transmission region R (the pixel in which the R color filter 2 is arranged), the fine particles 19 made of gold having a particle size distribution of 5 nm to 50 nm (median value: 15 nm) are SiO, which is a dielectric material. ₂ are arranged in series in (transparent planarizing film 3). In the pixel of the green transmission region G (the pixel in which the G color filter 2 is disposed), the fine particles 18 composed of cobalt titanium nickel zinc oxide having a particle size distribution of 5 nm to 50 nm (median value: 25 nm) are dielectric materials. Are arranged in series in SiO ₂ (transparent planarizing film 3). In the pixel of the blue transmission region B (the pixel in which the B color filter 2 is arranged), the fine particles 17 made of cobalt aluminum oxide having a particle size distribution of 5 nm to 50 nm (median value: 20 nm) are dielectric materials. They are arranged in series in SiO ₂ (transparent planarizing film 3). At this time, it is possible to realize excellent spectral characteristics due to plasmon light absorption by coupling of surface plasmons and visible light of fine particles 17, 18 and 19 having small particle diameters and electronic transition absorption of metals and metal oxides.

  FIG. 5 shows the light receiving sensitivity characteristics of the solid-state imaging device having the above structure.

  In FIG. 5, the sensitivity characteristic 21 of the pixel in the red transmission region R, the sensitivity characteristic 20 of the pixel in the green transmission region G, and the sensitivity characteristic 28 of the pixel in the blue transmission region B are shown. FIG. 5 shows that the solid-state imaging device exhibits excellent spectral characteristics in the red wavelength region, the green wavelength region, and the blue wavelength region.

  The fine particles 19 are made of gold. However, the fine particles 19 are not limited to this as long as they are made of a first type material including at least gold, silver, copper, aluminum, tantalum, chromium, and iron-chromium oxide. The fine particles 18 are made of cobalt titanium nickel zinc oxide. However, the fine particles 18 are of the second kind containing at least cobalt titanium nickel zinc oxide, cobalt titanium oxide, nickel titanium zinc oxide and cobalt zinc oxide. If it is comprised with material, it will not be restricted to this. Further, although the fine particles 17 are made of cobalt aluminum oxide, the fine particles 17 are not limited to this as long as they are made of a third type material including at least cobalt aluminum oxide and cobalt chrome oxide. By doing so, the fine particles are uniformly dispersed in the medium without agglomeration, and good color reproducibility without color variation between pixels can be realized. Further, when the first type of fine particles are used, a transmission filter mainly in the red region can be realized, and when the second type of fine particles is used, a transmission filter mainly in the green region can be realized, and the third type of fine particles is used. A transmission filter in the blue region can be realized. Further, the spectral characteristics of an arbitrary region can be realized by mixing the first, second, and third types of materials and selecting the proportions to form the fine particles 17, 18, and 19, respectively.

  Further, as shown in FIG. 6, the plasmonic waveguide of one pixel may have two or more kinds of fine particles composed of different particle sizes and materials. As described above, fine particles 19 made of gold having a particle size distribution of 5 nm to 50 nm (median value: 15 nm) are arranged in the pixels of the red transmission region R, and a particle size distribution of 5 nm to 50 nm is arranged in the green transmission region G. Fine particles 18 composed of cobalt titanium nickel zinc oxide (median value: 25 nm) are arranged, and the blue transmission region B is composed of cobalt aluminum oxide having a particle size distribution of 5 nm to 50 nm (median value: 20 nm). Fine particles 17 are arranged. However, it is not necessary that all the fine particles arranged between the microlens 1 and the light receiving element 6 are the same kind of fine particles. For example, as shown in FIG. 6, with respect to fine particles for guiding light (fine particles disposed between the microlens 1 and the wiring layer 5), the same material and the same particle size of 0.1 μm are used in all pixels. With respect to other fine particles (fine particles disposed between the wiring layer 5 and the light receiving element 6), fine particles of different materials may be used in pixels in which the color filters 2 of different colors are disposed. By adopting such a structure, it is possible to reduce the load on the manufacturing process in which different materials are arranged for each pixel and to suppress the cost.

  As described above, according to the solid-state imaging device of the present embodiment, the plurality of pixels include the pixels having the fine particles 19 made of the first type material and the fine particles 18 made of the second type material. And pixels having fine particles 17 made of the third type material. Therefore, since light in different wavelength ranges is guided to the light receiving element 6 in the three pixels, the fine particles can have a color filter function. As a result, it is not necessary to provide a color filter on the solid-state image sensor, and thus the size of the solid-state image sensor can be reduced.

(Embodiment 3)
7A and 7B are a top view and a cross-sectional view of a gradient index microlens arranged on the top surface of a solid-state imaging device of full HD specification (2 million pixels) according to the present embodiment.

Generally, in order for the gradient index microlens to have a convex lens effect, the refractive index of the gradient index microlens needs to be highest at the optical center 25. As shown in FIG. 7A, in the gradient index microlens of the present embodiment, SiO ₂ gathers densely near the center of the lens and becomes sparser as it becomes an outer zone region (region surrounded by a broken line in FIG. 7B). It will change. At this time, if the width 24 of each zone region is equal to or smaller than the wavelength of the incident light, the effective refractive index perceived by the light is a high refractive index material (for example, n = 1.45) in the zone region. It is determined by the volume ratio between the SiO ₂ ) 23 and the low refractive index material (for example, n = 1.00 air) 22. That is, if the high refractive index material 23 in the zone region is increased, the effective refractive index is increased, and if the high refractive index material 23 in the zone region is decreased, the effective refractive index is decreased (FIG. 7C).

  Here, the gradient index microlens has a quadrangular shape in accordance with the opening of each pixel. In general, when the area of the light incident window is circular, a gap is formed between the lenses, so that leakage light is generated and the light collection loss increases. However, if the area of the light incident window is rectangular, the incident light can be collected in the entire area of the pixel, so that there is no leakage light and the light collection loss can be reduced.

  FIG. 7D shows a modification of the gradient index microlens according to the present embodiment, that is, a cross-sectional view of a gradient index microlens having a two-stage structure.

This microlens has a two-stage structure of SiO ₂ having a thickness of 0.4 μm and SiO ₂ having a thickness of 0.8 μm. By changing not only the line width of the light transmission film (SiO ₂ ) but also the film thickness in each zone area (area surrounded by a broken line in FIG. 7D), it is possible to control the effective refractive index distribution with higher accuracy. Become. Note that this two-stage refractive index distribution type microlens is employed as the condensing element of the solid-state imaging device shown in FIG.

  FIG. 8 is a cross-sectional view of a solid-state imaging device of full HD specification (2 million pixels) according to the present embodiment.

  In this solid-state imaging device, the cell size is 0.45 μm square. The solid-state imaging device includes a gradient index microlens 26, a color filter 2, a transparent flattening film 3, a light shielding film 4, a wiring layer 5, a light receiving element 6, and a Si substrate 7. Yes. The transparent planarizing film 3, the light shielding film 4, the wiring layer 5, the light receiving element 6 and the Si substrate 7 constitute a semiconductor integrated circuit 8.

Here, the gradient index microlens 26 has a structure in which SiO ₂ (n = 1.45) is dug concentrically, and the surrounding medium is air (n = 1.00). The lens film thickness is 1.2 μm. It can be seen that the cross-sectional structure of the lens is not symmetrical with respect to the unit pixel.

  9A and 9B are a top view and a refractive index distribution of the refractive index distribution type microlens 26 having a convex lens effect according to the present embodiment.

  In the gradient index microlens 26, the center of the concentric structure (optical center 25) is shifted from the center of the pixel to form an eccentric structure (FIG. 9A), so that the effective refractive index distribution also has an asymmetric shape with respect to the pixel. (FIG. 9B). Therefore, the gradient index microlens 26 has not only a light collecting property but also a deflecting property.

  FIG. 9C is a diagram illustrating a state of light propagating through the asymmetric gradient index microlens 26.

  Incident light 27 incident at a specific angle is deflected by a refractive index distribution type microlens 26 having an asymmetric refractive index distribution with respect to the pixel center, and condensed on the pixel center axis. This suggests that the solid-state imaging device according to the present embodiment supports high-angle incidence, and even a nonlinear optical system in which light at various angles is incident on the surface of the solid-state imaging device is sufficient. It shows that it can respond to.

  As described above, according to the solid-state imaging device of the present embodiment, the condensing element is a gradient index microlens, and is divided by a line width that is the same as or shorter than the wavelength of the light to be collected. It has an effective refractive index distribution generated in a concentric light transmission film. Accordingly, the light incident at a high angle is also guided to the light receiving element 6 and the oblique incident characteristics of the light are improved, so that the sensitivity is improved.

(Embodiment 4)
FIG. 10 is a cross-sectional view of a solid-state image sensor of full HD specification (2 million pixels) according to the present embodiment.

  In this solid-state imaging device, the cell size is 0.45 μm square. The solid-state imaging device includes a microlens 1, a color filter 2, a transparent flattening film 3, a light shielding film 4, a wiring layer 5, a light receiving element 6, and a Si substrate 7. The transparent planarizing film 3, the light shielding film 4, the wiring layer 5, the light receiving element 6 and the Si substrate 7 constitute a semiconductor integrated circuit 8.

  Similar to the solid-state imaging device of the first embodiment, in the solid-state imaging device of the present embodiment, cubic fine particles 9 having a negative dielectric material and a particle size (particle size) of 0.1 μm are converted to the light wavelength in the Y direction. Plasmon light is propagated by periodically arranging in series at smaller intervals. At this time, in the solid-state imaging device of the present embodiment, plasmon light generated by light scattering by the fine particles 9 is used. However, if the particle size of the uppermost fine particle 9 (the fine particle 9 closest to the light incident surface) on which light is incident is too small than the wavelength, the fine particle 9 is less likely to scatter incident light, and the conversion efficiency to plasmon is reduced. Decreases. Therefore, in the present embodiment, the particle size in the X direction of the uppermost fine particle 9 in each pixel is set to 0.2 μm, for example, to be larger than the other fine particles 9. Thereby, scattering of incident light easily occurs in the fine particles 9, and plasmon conversion efficiency is increased.

  As described above, according to the solid-state imaging device of the present embodiment, among the plurality of fine particles 9 arranged in a row in one pixel, the fine particles 9 arranged on the microlens 1 side are arranged on the light receiving device 6 side. It has a larger particle size than the fine particles 9 that are formed. Accordingly, the plasmon conversion efficiency is increased and the sensitivity is improved.

  Although the solid-state imaging device of the present invention has been described based on the embodiment, the present invention is not limited to this embodiment. The present invention includes various modifications made by those skilled in the art without departing from the scope of the present invention.

  For example, in the above embodiment, the fine particles constituting the plasmonic waveguide are fine particles having a spherical shape or a cubic shape. However, a plasmonic waveguide that guides red, blue, and green light to a light-receiving element if the particle size representing a particle size and one side is 5 nm to 500 nm and the constituent material is a fine dielectric material. Therefore, the shape is not limited to a spherical shape or a cubic shape.

  In the above embodiment, the fine particles are arranged at intervals of 0.2 μm in the Y direction. However, if the fine particles are arranged in the Y direction at intervals smaller than the wavelength of the incident light, plasmon polaritons generated by the incident light can be propagated between the fine particles, and thus the interval is not limited to 0.2 μm.

  The solid-state imaging device of the present invention can be used for image sensor-related products such as digital video cameras, digital still cameras, camera-equipped mobile phones, surveillance cameras, in-vehicle cameras, and broadcast cameras, and the performance is improved. In addition, it is industrially useful because the price can be reduced.

1 is a diagram illustrating a structure of a solid-state imaging device according to Embodiment 1. FIG. 3 is a diagram showing a light propagation profile of the solid-state imaging device according to Embodiment 1. FIG. FIG. 5 is a diagram illustrating a manufacturing process of the plasmonic waveguide according to the first embodiment. 6 is a diagram illustrating a structure of a solid-state imaging device according to Embodiment 2. FIG. It is a figure which shows the spectral sensitivity characteristic of the solid-state image sensor which concerns on Embodiment 2. FIG. It is a figure which shows the structure of the modification of the solid-state image sensor which concerns on Embodiment 2. FIG. 6 is a top view of a gradient index microlens according to Embodiment 3. FIG. 6 is a cross-sectional view of a gradient index microlens according to Embodiment 3. FIG. 6 is a diagram showing a refractive index distribution of a gradient index microlens according to Embodiment 3. FIG. FIG. 10 is a diagram illustrating a cross-sectional view of a modification of the gradient index microlens according to the third embodiment. 6 is a diagram illustrating a structure of a solid-state imaging device according to Embodiment 3. FIG. 6 is a top view of a gradient index microlens according to Embodiment 3. FIG. 6 is a diagram showing a refractive index distribution of a gradient index microlens according to Embodiment 3. FIG. 6 is a diagram illustrating optical characteristics of a gradient index microlens according to Embodiment 3. FIG. FIG. 6 is a diagram illustrating a structure of a solid-state imaging device according to a fourth embodiment. It is a figure which shows an example of the basic structure of the conventional common pixel. It is a figure which shows the light propagation profile of the incident light in the conventional solid-state image sensor. It is a figure which shows the cell size dependence of the aspect-ratio and sensitivity of the conventional solid-state image sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Micro lens 2 Color filter 3 Transparent flattening film 4 Light shielding film 5 Wiring layer 6 Light receiving element 7 Si substrate 8 Semiconductor integrated circuit 9, 17, 18, 19 Fine particle 10, 27 Incident light 11 Resist 12 Photolithography 13 Dry etching 14 Gold Evaporation 15 Gold 16 CMP
20 Sensitivity characteristics of pixels in the green transmission area G 21 Sensitivity characteristics of pixels in the red transmission area R 28 Sensitivity characteristics of pixels in the blue transmission area B 22 Low refractive index material 23 High refractive index material 24 Zone area width 25 Optical center 26 Refraction Rate distribution type micro lens

Claims (8)

A solid-state imaging device comprising a plurality of pixels each having a light collecting element and a light receiving element that receives light collected by the light collecting element,
The pixel is
A dielectric material provided between the light collecting element and the light receiving element;
A plurality of fine particles having a particle size of 5 nm to 500 nm, which is formed of a negative dielectric material having a negative dielectric constant, which is provided in the dielectric material in the vicinity of and continuously in the direction from the light collecting element to the light receiving element. A solid-state imaging device. The fine particles are at least one of gold, silver, copper, aluminum, tantalum, chromium, iron chromium oxide, cobalt titanium oxide, nickel titanium zinc oxide, cobalt zinc oxide, cobalt aluminum oxide, and cobalt chromium oxide. The solid-state imaging device according to claim 1, comprising: 2. The solid-state imaging device according to claim 1, wherein the plurality of pixels include pixels having fine particles made of a first type of material and pixels having fine particles made of a second type of material. The plurality of pixels are:
A pixel having fine particles composed of at least one of gold, silver, copper, aluminum, tantalum, chromium, and iron chromium oxide;
A pixel having fine particles composed of at least one of cobalt titanium oxide, nickel titanium zinc oxide, and cobalt zinc oxide;
The solid-state image sensor of Claim 3. The solid-state imaging device according to claim 1, wherein one pixel includes two or more kinds of fine particles made of different materials. Among a plurality of fine particles arranged in a row in one pixel, the first fine particles arranged on the light collecting element side have a larger particle size than the second fine particles arranged on the light receiving element side. The solid-state image sensor of any one of Claims 1-5. The said condensing element is provided with the effective refractive index distribution produced in the light-transmitting film | membrane of the concentric structure divided | segmented by the line | wire width which is comparable or shorter than the wavelength of the light to condense. The solid-state imaging device according to item 1. A solid-state imaging device manufacturing method comprising a plurality of pixels each having a light collecting element and a light receiving element that receives light collected by the light collecting element,
A negative dielectric having a negative dielectric constant in a dielectric material provided between the light condensing element and the light receiving element, in a form that is arranged close to and continuously in the direction from the light condensing element to the light receiving element. A method for producing a solid-state imaging device, wherein a plurality of fine particles having a particle size of 5 nm to 500 nm composed of a body material are formed.