JP2009100463A - Solid-state imaging device and imaging apparatus - Google Patents

Abstract

A solid-state imaging device capable of improving the resolution of luminance components and the degree of design freedom without substantially reducing color reproducibility and color resolution.
In a solid-state imaging device including photodiodes arranged in a matrix, a high-sensitivity G filter HG that simultaneously obtains a luminance component and a hue component of G is applied to the photodiodes arranged in a checkered pattern among the photodiodes. The color filters R, G, and B are provided on the remaining photodiodes that are provided and are not provided with the luminance filter. The high-sensitivity G filter HG is a filter that transmits light in the entire visible light region and has higher transmittance of green light than that of light of other colors.
[Selection] Figure 2

Description

  The present invention relates to a solid-state imaging device and an imaging apparatus capable of obtaining a high-resolution luminance component.

  In order to obtain a high-resolution luminance component from a solid-state imaging device, there has been proposed one in which sampling points of a photosensitive element for extracting a luminance component are arranged in a checkered pattern.

  The solid-state imaging device described in Patent Document 1 has a luminance filter and a color filter arranged in a checkered pattern in a light receiving region. When using this image sensor, luminance information and color information are detected separately from the luminance filter and the color filter, so that it is possible to obtain a luminance resolution independent of the color information and a color reproduction independent of the spectral characteristics of the luminance information. it can.

JP 2003-318375 A

  However, in the image sensor described in Patent Document 1, since the luminance filter captures all the color information into the photoelectric conversion unit of the image sensor, for example, when an extremely bright subject is imaged, the charge accumulated in the photoelectric conversion unit is reduced. When the luminance increases significantly and it becomes difficult to perform proper brightness adjustment, and at the same time, color mixing occurs due to the phenomenon that the charge accumulated in the photoelectric conversion unit flows into the adjacent vertical charge transfer unit, resulting in a decrease in color reproducibility and color resolution. There is. Therefore, when shooting a bright subject, it is necessary to take measures such as changing the exposure setting. In addition, since color information is essentially not obtained from the light receiving area where the luminance filter is arranged, a decrease in color reproducibility is unavoidable as compared with an image sensor in which a color filter is arranged in the entire light receiving area.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid-state imaging device capable of improving the resolution of luminance components without substantially reducing color reproducibility and color resolution. To do. It is another object of the present invention to provide an imaging apparatus with few restrictions during imaging.

  The solid-state imaging device of the present invention is a solid-state imaging device in which a plurality of photosensitive elements are arranged in a matrix, and the photosensitive element includes a first photosensitive element for obtaining a luminance component and a hue component at the same time, and mainly a hue. And a hue photosensitive element for obtaining a component.

  The solid-state imaging device of the present invention includes one in which the first photosensitive elements are arranged at a uniform density.

  The solid-state imaging device of the present invention includes one in which the first photosensitive element has a spectral sensitivity over the entire visible light region and has a spectral sensitivity for green higher than that for other colors.

  The solid-state imaging device of the present invention includes one in which the hue photosensitive element is a plurality of types of photosensitive elements having different spectral sensitivities.

  The solid-state imaging device of the present invention includes those in which the plurality of types of photosensitive elements are photosensitive elements having spectral sensitivity with respect to magenta and photosensitive elements having spectral sensitivity with respect to yellow.

  In the solid-state imaging device of the present invention, the plurality of types of photosensitive elements are a photosensitive element having a spectral sensitivity for red, a photosensitive element having a spectral sensitivity for green, and a photosensitive element having a spectral sensitivity for blue. Including some.

  In the solid-state imaging device of the present invention, the plurality of types of photosensitive elements include a photosensitive element having a spectral sensitivity for green, a photosensitive element having a spectral sensitivity for cyan, and a photosensitive element having a spectral sensitivity for magenta. And a photosensitive element having spectral sensitivity to yellow.

  In the solid-state imaging device of the present invention, the hue photosensitive element is a photosensitive element that is exposed via a color filter, and the first photosensitive element is a color filter made of the same material as any one of the color filters. And the film thickness of the color filter of the first photosensitive element is smaller than the film thickness of the color filter of the hue photosensitive element.

  The solid-state imaging device of the present invention includes one in which the number of the first photosensitive elements is the same as the number of the hue photosensitive elements.

  The solid-state imaging device of the present invention includes one in which the plurality of photosensitive elements are arranged in a square lattice shape, and the first photosensitive element is arranged in a checkered position of the square lattice.

  In the solid-state imaging device of the present invention, the first photosensitive element and the hue photosensitive element are each arranged in a square lattice pattern having the same pitch, and each square lattice is arranged in the row direction and ½ pitch from each other. Includes those that are shifted in the column direction.

  The solid-state imaging device of the present invention includes one in which the solid-state imaging device is a MOS type solid-state imaging device.

  The solid-state imaging device of the present invention includes one in which the solid-state imaging device is a CCD type solid-state imaging device.

  The solid-state imaging device of the present invention is an imaging device equipped with the above-described solid-state imaging device.

  The solid-state imaging device of the present invention includes an apparatus that performs an AF operation using only a signal from the first photosensitive element.

  As is clear from the above description, it is possible to provide a solid-state imaging device that can improve the resolution of the luminance component without substantially reducing the color reproducibility and the color resolution, and at the time of imaging. It is possible to provide a solid-state imaging device that does not have a restriction.

  FIG. 1 is a diagram illustrating a schematic configuration of a digital camera which is an example of an imaging apparatus according to an embodiment of the present invention. The imaging system of the digital camera shown in the figure includes a photographic lens 1, a CCD type solid-state imaging device 5, a diaphragm 2 provided therebetween, an infrared cut filter 3, and an optical low-pass filter 4. Details of the solid-state imaging device 5 will be described later.

  A system control unit 11 that performs overall control of the electrical control system of the digital camera controls the flash light emitting unit 12 and the light receiving unit 13 and controls the lens driving unit 8 to adjust the position of the photographing lens 1 to the focus position and zoom. The exposure amount is adjusted by adjusting the aperture amount of the aperture 2 via the aperture drive unit 9.

  In addition, the system control unit 11 drives the solid-state imaging device 5 via the imaging device driving unit 10 and outputs a subject image captured through the photographing lens 1 as a color signal. An instruction signal from the user is input to the system control unit 11 through the operation unit 14.

  The electric control system of the digital camera further includes an analog signal processing unit 6 that performs analog signal processing such as correlated double sampling processing connected to the output of the solid-state imaging device 5, and a signal output from the analog signal processing unit 6. And an A / D conversion circuit 7 for converting the signal into a digital signal, which are controlled by the system control unit 11.

  Furthermore, the electric control system of this digital camera generates image data by performing main memory 16, memory control unit 15 connected to main memory 16, interpolation calculation, gamma correction calculation, RGB / YC conversion processing, and the like. A digital signal processing unit 17, a compression / decompression processing unit 18 that compresses image data generated by the digital signal processing unit 17 into a JPEG format or decompresses compressed image data, and a digital signal processing unit 17 that integrates photometric data. The integration unit 19 for obtaining the gain of white balance correction performed by the camera, the external memory control unit 20 to which the removable recording medium 21 is connected, and the display control unit 22 to which the liquid crystal display unit 23 mounted on the back of the camera is connected. These are connected to each other by a control bus 24 and a data bus 25, and are controlled by commands from the system control unit 11. That.

  FIG. 2 is a schematic diagram of the surface of the light receiving region of the solid-state imaging device according to the first embodiment of the present invention. FIG. 2 shows only a range of 5 rows and 5 columns, but in actuality, the arrangement shown in the drawing is repeated vertically and horizontally.

  The light receiving region 46 of the solid-state imaging device according to the present embodiment has a high-sensitivity G filter HG, color filters R, G, and B on each surface of a large number of photodiodes (not shown) arranged in a square lattice pattern. (However, the surface here includes not only that the filter is directly provided on the surface of the semiconductor substrate, but also that provided on the surface side with a predetermined interval.) Is the same). The high-sensitivity G filter HG is provided on the surface of the photodiode arranged at the checkered position of the square lattice among the individual photodiodes arranged vertically and horizontally. Further, the color filters R, G, and B are provided above the surface of the photodiode disposed at the remaining position of the square lattice. The number of high-sensitivity G filters HG and the number of color filters (R, G, B) (the total number of RGB) is the same. However, the identity here is not exact, and the density and number of high-sensitivity G filters HG and color filters (R, G, B) may not be exactly the same depending on the layout of the periphery of the photosensitive element. Including. In the following description, red, green, and blue may be simply described as R, G, and B.

  In the solid-state imaging device 1 illustrated in FIG. 2, filters aligned with “HG, G, HG, G,...” Are arranged on the individual surfaces of the even-numbered photodiodes, and on the individual surfaces of the odd-numbered photodiodes. , Filters arranged in line with “R, HG, B, HG, R,...” And filters arranged in line with “B, HG, R, HG, B,.

  The filter HG is a filter that transmits light in the entire visible light region and has higher transmittance of green light than that of light of other colors. Therefore, the photodiode below the high-sensitivity G filter HG has spectral sensitivity over the entire visible light region, and has higher spectral sensitivity for green than that for other colors. Therefore, a luminance component and a G hue component can be obtained at the same time. The color filters R, G, and B are filters that transmit red light, green light, and blue light, respectively. Accordingly, the photodiodes below the color filters R, G, and B are hue photosensitive elements having spectral sensitivity with respect to red, green, and blue, respectively.

  FIG. 3 is an example of the spectral characteristics of the high-sensitivity G filter HG and the color filters R, G, and B. In the visible light region, the color filters R, G, and B have characteristics as illustrated, and transmit red light, green light, and blue light, respectively. The high-sensitivity G filter HG is a characteristic obtained by shifting the characteristics of the color filter G as a whole as shown in the figure. The green light transmission amount is larger than that of the color filter G, and light of other colors is also transmitted. To do.

  Since the high-sensitivity G filter has the characteristics as shown in FIG. 3, the photodiode disposed below the high-sensitivity G filter can simultaneously obtain a luminance component and a hue component. In addition, since the amount of light other than green light is reduced, it also functions as a filter that suppresses excessive inflow of charges accumulated in the photodiode, which is a photoelectric conversion unit, when an extremely bright subject is imaged To do. Accordingly, a highly sensitive luminance component can be obtained without degrading color reproducibility and color resolution due to color mixing.

  FIG. 4 is a schematic cross-sectional view of an example of the solid-state imaging device according to the first embodiment of the present invention. 4A is a schematic cross-sectional view of odd-numbered rows of the solid-state image sensor of FIG. 2, and FIG. 4B is a schematic cross-sectional view of even-numbered rows of the solid-state image sensor of FIG.

  As shown in FIG. 4, the solid-state imaging device includes photodiodes 38 that are photoelectric conversion units arranged on the surface of an n-type silicon substrate 37. Above each photodiode 38, a high-sensitivity G filter 39HG, In addition, color filters 39B, 39G, and 39R are formed. The high sensitivity G filter 39HG is formed on the translucent region 40. Since this filter is formed of a material having the same or similar transmission characteristics as the color filter 39G, the amount of green light transmitted is larger than that of the color filter 39G, and the amount of light blocks of other colors is larger than that of the color filter 39G. The characteristic becomes smaller as shown in FIG.

  The color filters 39R, 39G, and 39B are directly formed on the planarizing film 42 on each photosensitive element 38, and the microlens 41 is formed on the high-sensitivity G filter 39HG and the color filters 39B, 39G, and 39R. In addition, as a resin film which comprises the translucent area | region 40, the resist material (for example, C series by Fuji Film Electronics Materials Co., Ltd.) which has translucency with respect to visible light, or thermosetting (non-photosensitive) Use materials. Although not shown in FIG. 4, elements, electrodes, wirings, and the like for reading out signal charges photoelectrically converted by the photodiodes 38 or signals based on the signal charges are provided above the silicon substrate 37 and the silicon substrate 37. It is done.

  FIGS. 5A and 6A are schematic cross-sectional views of other examples of the solid-state imaging device according to the first embodiment of the present invention. 5A is a cross-sectional view taken along the line AA in FIG. 5B, and FIG. 6A is a cross-sectional view taken along the line BB in FIG. 6B. A difference from the solid-state imaging device of FIG. 4 is that the high-sensitivity G filter 39HG and the color filter 39G are integrally formed of the same material. That is, the light-transmitting region 40 below the high-sensitivity G filter 39HG is formed by patterning with high accuracy by dry etching and then filling the opening with the high-sensitivity G filter 39HG and the color filter 39G with the same material. In FIGS. 5A and 6A, only the filter portion is shown, and the semiconductor substrate, the microlens, and the like are omitted. The film on the planarizing film 42 is a passivation film 43.

  Next, a manufacturing process of the color filter in the solid-state imaging device shown in FIGS. 5A and 6A will be described in detail with reference to FIGS. In these figures, “39R” is attached to the red color filter, “39G” to the green color filter, “39B” to the blue color filter, and “39HG” to the high sensitivity G color filter. is doing. Further, a CMP process for planarization is performed. As each of the RGB color filter materials, a material whose polishing rate is about 1: 1 with the resist in the CMP process is used. In the following description, green “G” may be described as a first color, red “R” as a second color, and blue “B” as a third color. In each drawing, the lower layer than the planarizing film 42 is omitted.

  First, as shown in FIG. 7A, after a wiring layer (not shown) is formed on the planarizing film 42, a passivation film 43 made of a silicon nitride film is formed by plasma CVD, and this passivation film 43 is formed. On the top, as shown in FIG. 7B, a resin film for forming the translucent region 40 is formed by a coating method.

  Then, as shown in FIG. 8A, a resist pattern R1 is formed by photolithography. Thereafter, as shown in FIG. 8B, a first opening O1 is formed by reactive ion etching (RIE) using the resist pattern R1 as a mask. Here, the lower silicon nitride film 43 functions as an etching stopper. The first opening is formed only in the portion where the green color filter 39G is formed.

  Then, a green color filter material is applied as a color filter material of the first color so as to be 0.5 to 2.0 μm. This color filter material has photosensitivity. By this step, the green color filter material is filled in the first opening O1 and applied also on the resist pattern R1. In this state, only the green color filter 39G is cured by heat treatment and partial UV irradiation (FIG. 8C), and the resist pattern R1 on the translucent region 40 and the green color filter 39G are formed by CMP. The color filter material is polished and flattened (FIG. 8D).

  And as shown in FIG.8 (e), the same color filter material as the color filter material of FIG.8 (c) is apply | coated so that it may become 0.1-1.0 micrometer. In this state, heat treatment and ultraviolet irradiation are performed to cure only the green color filter 39G portion and the high-sensitivity G filter 39HG portion (above the translucent region 40). Thereafter, CMP may be performed to obtain a desired film thickness. By this step, a green color filter material is formed on the light-transmitting region 40 and the green color filter material filled in the opening O1. At this time, the part of the green color filter above the translucent region 40 is in a cured state.

  FIG. 9 shows an embodiment in which the manufacturing process (c) and subsequent steps in FIG. 8 are changed. After the steps of FIGS. 9A and 9B, which are the same steps as the steps of FIGS. 8A and 8B, the resist pattern R1 is removed under the conditions of solvent or dry etching (FIG. 9). (C)). Thereafter, as shown in FIG. 9 (d), a green color filter material is applied on the opening O1 and the translucent region 40, and in FIG. 9 (e), a high-sensitivity G filter 39HG and a green color filter are respectively obtained by CMP. 39G is formed. Here, the high-sensitivity G filter 39HG and the green color filter 39G are in a cured state as in FIG. 8 and 9 show the AA cross section of FIG. 5B.

  After FIG. 8E or FIG. 9E, as shown in FIG. 10A, a resist pattern R2 for forming a red color filter pattern is formed by photolithography. Here, it has a shape having an opening in a region to be a red color filter.

  Thereafter, as shown in FIG. 10B, reactive ion etching (RIE), which is anisotropic dry etching, is performed using the resist pattern R2 as a mask to form a red color filter material pattern. Two openings O2 are formed. Again, the underlying silicon nitride film 43 acts as an etching stopper.

  Then, with the resist pattern R2 left, a red color filter material is applied so as to have a film thickness of 0.5 to 2.0 μm, and only a portion of the red color filter 39R is cured by heat treatment and ultraviolet irradiation. (FIG. 10C). Thereafter, CMP is performed to flatten the surface to form a red color filter 39R (FIG. 11A).

  Thereafter, as shown in FIG. 11B, a resist pattern R3 for forming a blue color filter pattern is formed by photolithography. Here, it has a shape having an opening in a region to be a blue color filter.

  Thereafter, as shown in FIG. 11C, reactive ion etching (RIE), which is anisotropic dry etching, is performed using the resist pattern R3 as a mask to form a blue color filter material pattern. 3 openings O3 are formed. Again, the underlying silicon nitride film 43 acts as an etching stopper.

  Then, while leaving the resist pattern R3, the blue color filter material 39B (B) is applied, and heat treatment and ultraviolet irradiation are performed to cure only the portion of the blue color filter 39R (FIG. 12A). Thereafter, CMP is performed to flatten the surface to form a blue color filter 39B (FIG. 12B).

  By this CMP process, the color filter surface of each color is flat, and a highly accurate color filter pattern can be formed without residue.

  Then, on the color filter, a resist material that is transparent to visible light (for example, C series manufactured by FUJIFILM Electronics Materials Co., Ltd.) is applied to form a planarizing film 44. Thereafter, a microlens 45 is formed on the planarizing film 44 by an etching method or a melt method (FIG. 12C), so that a solid-state imaging device as shown in FIGS. It is formed.

  In the manufacturing process described above, CMP is used for the planarization process, but other methods such as resist etch back may be used.

  FIG. 13 is a schematic diagram of the surface of the light receiving region of the solid-state imaging device according to the second embodiment of the present invention. Note that the image pickup element in FIG. 13 is not in a square lattice shape as shown in FIG. 2, but photodiodes are arranged in a checkered pattern. Although FIG. 13 shows only the range of 7 rows and 7 columns, the arrangement shown in FIG. 13 is actually repeated vertically and horizontally.

  The light receiving region 47 of the solid-state imaging device of the present embodiment is provided with a high-sensitivity G filter HG and color filters R, G, and B on the individual surfaces of a number of photodiodes (not shown) arranged in a checkered pattern. Yes. This arrangement becomes an array of square lattices when tilted at an angle of 45 °, and the high-sensitivity G filter HG is arranged on the surface of the photodiode in the checkered arrangement position of the square lattice array inclined at an angle of 45 °. The color filters R, G, and B are provided on the surface of the remaining photodiode in the checkered arrangement position. That is, in the solid-state imaging device illustrated in FIG. 13, “G, HG, G, HG, G,...” And “R, HG, B, HG,. R ... "are alternately arranged.

  From the viewpoint of the arrangement in FIG. 13, it can be considered that two square lattice arrays having the same pitch are shifted in the row direction and the column direction by ½ pitch. From such a viewpoint, a high-sensitivity G filter HG is arranged on the surface of one of the photodiodes arranged in a square lattice, and the surface of the photodiode arranged in the other square lattice is arranged on the surface of the photodiode. The color filters R, G, and B are arranged in a so-called Bayer array.

  FIG. 14 is a schematic diagram of the surface of the light receiving region of the solid-state imaging device according to the third embodiment of the present invention. FIG. 14 shows only a range of 5 rows and 5 columns, but in actuality, the arrangement shown in FIG. 14 is repeated vertically and horizontally.

  The light receiving region 48 of the solid-state imaging device according to the present embodiment includes a high-sensitivity G filter HG and color complementary color filters C1 and C2 on each surface of a large number of photodiodes (not shown) arranged in a square lattice pattern vertically and horizontally. Provided. The high-sensitivity G filter HG is provided on the surface of the photodiode in the checkered arrangement position among the individual photodiodes arranged vertically and horizontally, and the color filters C1 and C2 are the remaining checkered arrangement positions. It is provided on the surface of the photodiode.

  In other words, in the solid-state imaging device illustrated in FIG. 14, filters “HG, C1, HG, C1, HG...” Are arranged on the individual surfaces of the even-numbered photodiodes, and , “C2, HG, C2, HG, C2,...” Rows are alternately arranged.

  The high-sensitivity G filter HG can be said to be a filter that simultaneously obtains a luminance component and a hue component of G, that is, a luminance & high-sensitivity G filter, and transmits a certain amount of light of the hue components C1 and C2. This high-sensitivity G filter HG can be realized by thinly forming the material of the color filter 39G shown in FIG.

  Further, if the color filters C1 and C2 transmit magenta and yellow, respectively, high-sensitivity hue information can be obtained because the entire visible light region includes a green hue component having spectral sensitivity.

  FIG. 15 is a schematic diagram of the surface of the light receiving region of the solid-state imaging device according to the fourth embodiment of the present invention. In the image pickup device of FIG. 15, photodiodes are arranged in a checkered pattern as in the case of FIG. 13. FIG. 15 shows only a range of 7 rows and 7 columns, but in actuality, the arrangement shown in FIG. 15 is repeated vertically and horizontally.

  In the light receiving region 49 of the solid-state imaging device of the present embodiment, a high-sensitivity G filter HG and color complementary color filters C1 and C2 are provided on individual surfaces of a number of photodiodes (not shown) arranged in a checkered pattern. . This arrangement becomes a square lattice arrangement when tilted at an angle of 45 °, and the high-sensitivity G filter HG has a square lattice arrangement inclined at an angle of 45 ° in the checkered arrangement surface of the photodiode. The color filters C1 and C2 are provided on the surface of the remaining photodiodes in the checkered arrangement position. That is, in the solid-state imaging device 48 illustrated in FIG. 15, “C1, HG, C1, HG, C1...” And “C2, HG, C2, HG,. “C2,...” Are alternately arranged.

  In the arrangement of FIG. 15, it can be considered that two square lattice arrangements having the same pitch are shifted in the row direction and the column direction by 1/2 pitch with respect to each other as in the arrangement of FIG. From such a viewpoint, a high-sensitivity G filter HG is arranged on the surface of one of the photodiodes arranged in a square lattice, and the surface of the photodiode arranged in the other square lattice is arranged on the surface of the photodiode. Color filters C1 and C2 are arranged. Also in this example, the color filters C1 and C2 that can transmit magenta and yellow can be used.

  FIG. 16 is a schematic diagram of the surface of the light receiving region of the solid-state imaging device according to the fifth embodiment of the present invention. FIG. 16 shows only the range of 5 rows and 5 columns, but in actuality, the arrangement shown in FIG. 16 is repeated vertically and horizontally.

  The light receiving region 50 of the solid-state imaging device of the present embodiment has a high-sensitivity G filter HG and color filters G, Cy, Ye, Mg is provided. The high-sensitivity G filter HG is provided on the surface of the photodiodes arranged in a checkered pattern among the individual photodiodes arranged vertically and horizontally, and the color filters G, Cy, Ye, and Mg are the remaining checkers. It is provided on the surface of the photodiode that is in the shape of the arrangement.

  That is, in the solid-state imaging device illustrated in FIG. 16, filters “HG, Cy, HG, Mg, HG...” Are arranged on the individual surfaces of even-numbered photodiodes, and , “G, HG, Ye, HG, G,...” Rows are alternately arranged.

  The high-sensitivity G filter HG can be said to be a filter that simultaneously obtains a luminance component and a hue component of G, that is, a luminance & high-sensitivity G filter, and can be realized by thinly forming the material of the color filter 39G shown in FIG. The color filters Cy, Ye, and Mg are complementary color filters that transmit cyan, yellow, and magenta, respectively. The color filter G transmits green.

  FIG. 17 is a schematic view of the surface of the light receiving region of the solid-state imaging device according to the sixth embodiment of the present invention. In the image pickup device of FIG. 17, photodiodes are arranged in a checkered pattern, as in the case of FIG. FIG. 17 shows only the range of 7 rows and 7 columns, but in actuality, the arrangement shown in FIG. 17 is repeated vertically and horizontally.

  The light receiving region 51 of the solid-state imaging device of the present embodiment includes a high-sensitivity G filter HG and color filters G, Cy, Ye, and Mg on the individual surfaces of a number of photodiodes (not shown) arranged in a checkered pattern. Provided. This arrangement becomes a square lattice arrangement when tilted at an angle of 45 °, and the high-sensitivity G filter HG has a square lattice arrangement inclined at an angle of 45 ° in the checkered arrangement surface of the photodiode. The color filters G, Cy, Ye, and Mg are provided on the surface of the remaining photodiodes in the checkered arrangement position. That is, in the solid-state imaging device 48 illustrated in FIG. 17, “HG, Cy, HG, Mg, HG...” And “G, HG, Ye, HG,. G, ... "are alternately arranged.

  In the arrangement of FIG. 17, like the arrangement of FIG. 13, it can be considered that two square lattice arrangements having the same pitch are arranged with a ½ pitch shift from each other in the row direction and the column direction. From such a viewpoint, a high-sensitivity G filter HG is arranged on the surface of one of the photodiodes arranged in a square lattice, and the surface of the photodiode arranged in the other square lattice is arranged on the surface of the photodiode. Color filters G, Cy, Ye, and Mg are arranged. As in FIG. 16, the color filters Cy, Ye, and Mg are complementary color filters that transmit cyan, yellow, and magenta, respectively, and the color filter G transmits green.

  As described above, according to the solid-state imaging device of the present invention, since the dedicated pixels for luminance information and hue detection are provided at the same time, the luminance resolution of the captured image is not greatly influenced by the brightness and color of the subject. Can be obtained.

  In the above description, the high-sensitivity G filter HG and the number (total number) of color filters (R, G, B, Cy, Mg, Ye) are arranged to be the same, but they need to be the same. There is no. The number of high sensitivity G filters HG may be large, and the number of color filters may be large.

  Next, a specific example of the MOS type color image sensor according to the embodiment of the present invention will be described with reference to FIG. FIG. 18 shows an example using a checkered array of photosensitive elements, but a square grid array of solid-state image sensors may also be used. In FIG. 18A, in the light receiving region 3, a high-sensitivity G filter HG that obtains a luminance component and a hue component of G and color filters R, G, and B as shown in FIG. 13 are arranged in a checkered pattern. ing. Therefore, the photodiodes arranged below the respective filters function as a first photosensitive element for obtaining a luminance component and a hue component at the same time, and a hue photosensitive element for mainly obtaining a hue component.

  These photosensitive elements (hereinafter referred to as HG, G, R, and B for convenience) are formed of photosensitive elements having their own spectral sensitivity characteristics, or photodiodes having the same photosensitive characteristics. Alternatively, a color filter having each spectral sensitivity characteristic may be stacked on a light receiving element such as the above.

  A vertical scanning circuit 4, a horizontal scanning circuit 5, and a selection circuit 6 are provided for the light receiving region 3. Further, each photosensitive element HG, G, R, B has a selection line Ly extended from the vertical scanning circuit 4 and a call line extended from the selection circuit 6 as shown in the conceptual diagram of FIG. It is connected to a switching element SW interposed between Lx.

  The vertical scanning circuit 4 selects the photosensitive elements HG, G, R, and B by supplying a vertical scanning signal synchronized with a predetermined vertical scanning timing to each selection line Ly. Further, the horizontal scanning circuit 5 Are generated in the photosensitive elements HG, G, R, and B selected by the selection lines Ly by sequentially turning on / off the switching elements in the selection circuit 6 with a horizontal scanning signal synchronized with the horizontal scanning timing. Each pixel signal is read out through each call line Lx.

  Next, a specific example of the CCD color solid-state imaging device according to the embodiment of the present invention will be described with reference to FIG. Although FIG. 19 shows an example using a checkered array of photosensitive elements, a solid-state image sensor having a square grid array may be used. In FIG. 19A, in the light receiving region 7, a high-sensitivity G filter HG that obtains a luminance component and a hue component of G and color filters R, G, and B as shown in FIG. 13 are arranged in a checkered pattern. ing. Therefore, the photodiodes arranged below the respective filters function as a first photosensitive element for obtaining a luminance component and a hue component at the same time, and a hue photosensitive element for mainly obtaining a hue component.

  These photosensitive elements (hereinafter referred to as HG, G, R, and B for convenience) are formed of photosensitive elements having their own spectral sensitivity characteristics, or photodiodes having the same photosensitive characteristics. Alternatively, a color filter having each spectral sensitivity characteristic may be stacked on a light receiving element such as the above.

  In this solid-state imaging device, as shown in the conceptual diagram of FIG. 19B, a vertical charge transfer path 9 is formed next to each photosensitive element HG, G, R, B via a transfer gate 8 to transfer the vertical charge. A number of transfer electrodes 11 are stacked on the upper surface of the path 9. The pixel signals of the photosensitive elements HG, G, R, and B are transmitted through the vertical charge transfer paths 9 in synchronization with a vertical transfer drive signal such as a four-phase drive method supplied from the vertical transfer circuit 10 to a predetermined transfer electrode 11. Vertical transfer.

  Further, a horizontal charge transfer path 12 is formed at the end portion of each vertical charge transfer path 9, and each pixel signal vertically transferred from each vertical charge transfer path 9 is supplied from the horizontal transfer circuit 13 in two phases. A pixel signal is read out by horizontal transfer in synchronization with a horizontal transfer drive signal such as a drive method.

  An AF (autofocus) operation when the solid-state imaging device described above is used in the digital camera shown in FIG. 1 will be described. The first photosensitive element (photosensitive element having a high-sensitivity G filter HG) for obtaining a luminance component and a hue component in the solid-state imaging device of the present invention outputs a relatively large signal even when the amount of light from the subject is small. To do. Therefore, in the high-sensitivity shooting mode in which the signal charge amount that is generally handled is small (when shooting with high ISO sensitivity and high sensitivity), AF control is performed by using only the first photosensitive element, thereby achieving high Accurate AF operation is possible. Note that such switching of AF control is performed by the system control unit 11.

1 is a diagram illustrating a schematic configuration of a digital camera that is an example of an imaging apparatus according to an embodiment of the present invention. The schematic diagram of the light-receiving area | region surface of the solid-state image sensor of the 1st Embodiment of this invention. FIG. 4 is a diagram illustrating an example of spectral characteristics of a filter provided in the solid-state imaging device according to the first embodiment of the present invention. 1 is a schematic cross-sectional view of an example of a solid-state imaging element according to a first embodiment of the present invention. FIG. 6 is a diagram illustrating another example of the solid-state imaging element according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating another example of the solid-state imaging element according to the first embodiment of the present invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The figure which shows the manufacturing process of the color filter of the 1st Embodiment of this invention. The schematic diagram of the light-receiving region surface of the solid-state image sensor of the 2nd Embodiment of this invention. The schematic diagram of the light-receiving region surface of the solid-state image sensor of the 3rd Embodiment of this invention. The schematic diagram of the light-receiving region surface of the solid-state image sensor of the 4th Embodiment of this invention. The schematic diagram of the light-receiving region surface of the solid-state image sensor of the 5th Embodiment of this invention. The schematic diagram of the light-receiving region surface of the solid-state image sensor of the 6th Embodiment of this invention. The figure which shows the structure of the specific example of the MOS type color image sensor of embodiment of this invention. The figure which shows the structure of the specific example of the CCD type color solid-state image sensor of embodiment of this invention.

Explanation of symbols

37... N-type silicon substrate 38... Photodiode 39HG... Filter 39R provided on the photosensitive element for extracting luminance and hue components... Filter 39G provided on the red photosensitive element. Filters C1 and C2 provided in the photosensitive elements of the filter. Filters 40 provided in the photosensitive element for extracting the hue component. Translucent regions 41 and 45... Microlenses 42 and 44. Flattening films 43. , 49, 50, 51... Light receiving region

Claims (15)

A solid-state imaging device in which a plurality of photosensitive elements are arranged in a matrix,
The photosensitive element includes a first photosensitive element for obtaining a luminance component and a hue component at the same time, and a hue photosensitive element mainly for obtaining a hue component. The solid-state imaging device according to claim 1,
The first photosensitive element is a solid-state imaging element arranged with a uniform density. The solid-state imaging device according to claim 1 or 2,
The first photosensitive element has a spectral sensitivity over the entire visible light region, and has a spectral sensitivity for green higher than that for other colors. It is a solid-state image sensing device according to any one of claims 1 to 3,
The hue photosensitive element is a solid-state imaging element which is a plurality of types of photosensitive elements having different spectral sensitivities. The solid-state imaging device according to claim 4,
The plurality of types of photosensitive elements are a solid-state imaging device which is a photosensitive element having a spectral sensitivity for magenta and a photosensitive element having a spectral sensitivity for yellow. The solid-state imaging device according to claim 4,
The plurality of types of photosensitive elements are a solid-state imaging device which is a photosensitive element having a spectral sensitivity for red, a photosensitive element having a spectral sensitivity for green, and a photosensitive element having a spectral sensitivity for blue. The solid-state imaging device according to claim 4,
The plurality of types of photosensitive elements include a photosensitive element having a spectral sensitivity for green, a photosensitive element having a spectral sensitivity for cyan, a photosensitive element having a spectral sensitivity for magenta, and a spectral sensitivity for yellow. A solid-state imaging device which is a photosensitive device having The solid-state imaging device according to any one of claims 1 to 7,
The hue photosensitive element is a photosensitive element that is exposed through a color filter,
The first photosensitive element is a photosensitive element that is exposed through a color filter made of the same material as any one of the color filters.
The solid-state imaging device, wherein the thickness of the color filter of the first photosensitive element is smaller than the thickness of the color filter of the hue photosensitive element. The solid-state imaging device according to any one of claims 1 to 8,
A solid-state imaging device in which the number of the first photosensitive elements is the same as the number of the hue photosensitive elements. The solid-state imaging device according to claim 9,
The plurality of photosensitive elements are arranged in a square lattice shape, and the first photosensitive elements are arranged at checkered positions of the square lattice. The solid-state imaging device according to claim 9,
The first photosensitive element and the hue photosensitive element are each arranged in a square lattice with the same pitch, and the square lattices are arranged so as to be shifted from each other in the row direction and the column direction by ½ pitch. Solid-state imaging device. It is a solid-state image sensing device according to any one of claims 1 to 11,
The solid-state imaging device is a MOS type solid-state imaging device. It is a solid-state image sensing device according to any one of claims 1 to 11,
The solid-state imaging device is a solid-state imaging device which is a CCD solid-state imaging device.   An imaging apparatus equipped with the solid-state imaging device according to claim 1. The imaging device according to claim 14,
An image pickup apparatus that performs an AF operation using only a signal from the first photosensitive element.

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