JP2017054984A - Solid-state imaging element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve phase difference detection characteristics.SOLUTION: A solid-state imaging element of an embodiment comprises: a semiconductor substrate including an upper surface and a lower surface and provided with a first light-receiving element region and a second light-receiving element region from the upper surface toward the lower surface, the second light-receiving element region juxtaposed to the first light-receiving element region; a first light-shielding film selectively provided on the first light-receiving element region; a first resin layer provided on the first light-receiving element region and the first light-shielding film; a first lens provided on the first resin layer; a second light-shielding film selectively provided on the second light-receiving element region; a second resin layer provided on the second light-receiving element region and the second light-shielding film; and a second lens provided on the second resin layer.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a solid-state imaging device.

  A camera having an autofocus function may use a CCD type or CMOS type solid-state imaging device. In such a solid-state imaging device, pixels including photoelectric conversion elements (hereinafter referred to as light receiving element regions) are two-dimensionally arranged. Furthermore, the autofocus function may employ a phase difference type focus detection method.

  However, in a pixel having a phase difference type focus detection function (hereinafter, a phase difference detection pixel), a part of the light receiving element region is shielded from light by the light shielding film. If a part of the light receiving element region is shielded by the light shielding film, a good phase difference detection characteristic may not be obtained.

Japanese Patent No. 5157436

  The problem to be solved by the present invention is to provide a solid-state imaging device with improved phase difference detection characteristics.

  The solid-state imaging device of the embodiment is a semiconductor substrate having an upper surface and a lower surface, and a first light receiving element region and a second light receiving element region are provided from the upper surface toward the lower surface, and the second light receiving element region is , A semiconductor substrate arranged in the first light receiving element region, a first light shielding film selectively provided on the first light receiving element region, the first light receiving element region, and the first light shielding film. A first resin layer provided on the first resin layer, a first lens provided on the first resin layer, a second light-shielding film selectively provided on the second light receiving element region, and the second A second resin layer provided on the light receiving element region and on the second light shielding film; and a second lens provided on the second resin layer.

  In the region where the first light receiving element region is provided, the upper surface of the semiconductor substrate includes a first surface on which the first light shielding film is provided and a second surface on which the first light shielding film is not provided. Including. A distance between the lower surface of the semiconductor substrate and the first surface is shorter than a distance between the lower surface of the semiconductor substrate and the second surface. In the region in which the second light receiving element region is provided, the upper surface of the semiconductor substrate includes a third surface on which the second light shielding film is provided and a fourth surface on which the second light shielding film is not provided. Including. A distance between the lower surface of the semiconductor substrate and the third surface is shorter than a distance between the lower surface of the semiconductor substrate and the fourth surface. In the direction from the first light receiving element region to the second light receiving element region, the second surface is located between the first light shielding film and the fourth surface, and the fourth surface is the second light receiving region. It is located between the surface and the second light shielding film.

FIG. 1A is a schematic cross-sectional view showing a solid-state imaging device according to this embodiment. FIG. 1B is a schematic plan view showing the solid-state imaging device according to the present embodiment. FIG. 2A is a schematic cross-sectional view illustrating a solid-state imaging device according to a first reference example and a schematic diagram illustrating a camera according to the first reference example. FIG. 2B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the first reference example. FIG. 3A is a schematic cross-sectional view showing a solid-state imaging device according to a first reference example and a schematic view showing a camera according to the first reference example. FIG. 3B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the first reference example. FIG. 4A is a schematic cross-sectional view illustrating a solid-state imaging device according to a second reference example and a schematic diagram illustrating a camera according to the second reference example. FIG. 4B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the second reference example. FIG. 5A is a schematic cross-sectional view illustrating a solid-state imaging device according to a second reference example and a schematic diagram illustrating a camera according to the second reference example. FIG. 5B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the second reference example. FIG. 6 is a schematic cross-sectional view illustrating the solid-state imaging device according to the present embodiment and a schematic diagram illustrating the camera according to the present embodiment. FIG. 7 is a schematic cross-sectional view illustrating a solid-state imaging device according to the present embodiment and a schematic diagram illustrating a camera according to the present embodiment. FIG. 8 is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the present embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same members are denoted by the same reference numerals, and the description of the members once described is omitted as appropriate. In the drawings, XYZ coordinates may be used.

  FIG. 1A is a schematic cross-sectional view showing a solid-state imaging device according to this embodiment. FIG. 1B is a schematic plan view showing the solid-state imaging device according to the present embodiment. FIG. 1A shows a cross section at a position along the line A1-A2 of FIG.

  The solid-state imaging device 1 according to this embodiment includes a semiconductor substrate 10 including a first light receiving element region 11 and a second light receiving element region 12, a first light shielding film 21, a first resin layer 31, and a first resin layer 31. The lens 41, the second light shielding film 22, the second resin layer 32, and the second lens 42 are included.

  The semiconductor substrate 10 has an upper surface 10u and a lower surface 10d. The semiconductor substrate 10 is a silicon substrate, for example. The semiconductor substrate 10 may be a nitride semiconductor substrate, a gallium arsenide substrate, or a silicon carbide substrate.

  In the drawings of the embodiment, the direction from the lower surface 10d of the semiconductor substrate 10 toward the upper surface 10u is the Z direction. The direction orthogonal to the Z direction is the X direction or the Y direction. The X direction is orthogonal to the Y direction. For example, the direction from the first light receiving element region 11 toward the second light receiving element region 12 is the Y direction.

  The first light receiving element region 11 is provided from the upper surface 10 u to the lower surface 10 d of the semiconductor substrate 10. The upper surface 10 u of the semiconductor substrate 10 is also the upper end of the first light receiving element region 11. The first light receiving element region 11 includes a photoelectric conversion element that generates a signal charge according to the amount of light incident on the first light receiving element region 11 via the first lens 41. This photoelectric conversion element is a Si photodiode.

  The first light shielding film 21 is selectively provided on the first light receiving element region 11. The lower surface 21 d of the first light shielding film 21 is located below the upper surface 10 u of the semiconductor substrate 10. The first light shielding film 21 is embedded in the first light receiving element region 11. In the region where the first light receiving element region 11 is provided, the upper surface 10u of the semiconductor substrate 10 includes the first surface 10-1 provided with the first light shielding film 21 and the first surface where the first light shielding film 21 is not provided. 2 side 10-2. The distance between the lower surface 10d of the semiconductor substrate 10 and the first surface 10-1 is shorter than the distance between the lower surface 10d of the semiconductor substrate 10 and the second surface 10-2. There is a step between the first surface 10-1 and the second surface 10-2. The material of the first light shielding film 21 includes, for example, aluminum (Al) or tungsten (W).

  The first resin layer 31 is provided on the first light receiving element region 11 and on the first light shielding film 21. The first resin layer 31 is in contact with the upper surface 21 u of the first light shielding film 21 and the upper end of the first light receiving element region 11, that is, the upper surface 10 u of the semiconductor substrate 10. The first resin layer 31 includes a translucent resin. The first resin layer 31 includes, for example, at least one of an acrylic resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, and the like.

  The first lens 41 is provided on the first resin layer 31. The focal point f1 of the first lens 41 is located on the upper surface 10u of the semiconductor substrate 10. The focal point f1 of the first lens 41 is located on the second surface 10-2 of the semiconductor substrate 10, for example. The first lens 41 includes, for example, at least one of acrylic resin, epoxy resin, polystyrene resin, polycarbonate resin, and the like. The refractive index of the first resin layer 31 may be the same as the refractive index of the first lens 41.

  The second light receiving element region 12 is provided from the upper surface 10 u to the lower surface 10 d of the semiconductor substrate 10. In the Y direction, the second light receiving element region 12 is provided beside the first light receiving element region 11. The upper surface 10 u of the semiconductor substrate 10 is also the upper end of the second light receiving element region 12. The second light receiving element region 12 includes a photoelectric conversion element that generates a signal charge according to the amount of light incident on the second light receiving element region 12 via the second lens 42. This photoelectric conversion element is a Si photodiode.

  The second light shielding film 22 is selectively provided on the second light receiving element region 12. The lower surface 22 d of the second light shielding film 22 is located below the upper surface 10 u of the semiconductor substrate 10. The second light shielding film 22 is embedded in the second light receiving element region 12. In the region where the second light receiving element region 12 is provided, the upper surface 10u of the semiconductor substrate 10 is the third surface 10-3 provided with the second light shielding film 22, and the fourth where the second light shielding film 22 is not provided. Surface 10-4. The distance between the lower surface 10d of the semiconductor substrate 10 and the third surface 10-3 is shorter than the distance between the lower surface 10d of the semiconductor substrate 10 and the fourth surface 10-4. There is a step between the third surface 10-3 and the fourth surface 10-4. The material of the second light shielding film 22 may be the same as the material of the first light shielding film 21. The material of the second light shielding film 22 includes, for example, aluminum (Al) or tungsten (W).

  The second resin layer 32 is provided on the second light receiving element region 12 and the second light shielding film 22. The second resin layer 32 is in contact with the upper surface 22 u of the second light shielding film 22 and the upper end of the second light receiving element region 12, that is, the upper surface 10 u of the semiconductor substrate 10. The second resin layer 31 includes a translucent resin. The second resin layer 32 includes at least one of an acrylic resin, an epoxy resin, a polystyrene resin, a polycarbonate resin, and the like, for example. The refractive index of the second resin layer 32 may be the same as the refractive index of the second lens 42.

  The second lens 42 is provided on the second resin layer 32. The focal point f2 of the second lens 42 is located on the upper surface 10u of the semiconductor substrate 10. The focal point f2 of the second lens 42 is located on the fourth surface 10-4 of the semiconductor substrate 10. The second lens 42 includes, for example, at least one of acrylic resin, epoxy resin, polystyrene resin, polycarbonate resin, and the like.

  In the Y direction, a part 11 a of the first light receiving element region 11 and a part 12 a of the second light receiving element region 12 are provided between the first light shielding film 21 and the second light shielding film 22. For example, in the Y direction, the first light shielding film 21, the part 11a of the first light receiving element region 11, the second light shielding film 22, and the part 12a of the second light receiving element region 12 are arranged in this order. A part 12a of the second light receiving element region 12 is aligned with a part 11a of the first light receiving element region 11 in the Y direction. In the Y direction, the second surface 10-2 of the semiconductor substrate 10 is located between the first light shielding film 21 and the fourth surface 10-4. Further, in the Y direction, the fourth surface 10-4 of the semiconductor substrate 10 is located between the second surface 10-2 and the second light shielding film 22.

  There is no step between the first light shielding film 21 and the part 11 a of the first light receiving element region 11. There is no step between the upper surface 21 u of the first light shielding film 21 and the second surface 10-2 of the semiconductor substrate 10. The distance between the lower surface 10 d of the semiconductor substrate 10 and the upper surface 21 u of the first light shielding film 21 is between the lower surface 10 d of the semiconductor substrate 10 and the upper end of the first light receiving element region 11, that is, the upper surface 10 u of the semiconductor substrate 10. Same as distance. A flat surface is formed by the upper surface 21 u of the first light shielding film 21 and the upper surface 10 u of the semiconductor substrate 10 adjacent to the first light shielding film 21.

  There is no step between the second light shielding film 22 and the part 12a of the second light receiving element region 12. There is no step between the upper surface 22 u of the second light shielding film 22 and the fourth surface 10-4 of the semiconductor substrate 10. The distance between the lower surface 10d of the semiconductor substrate 10 and the upper surface 22u of the second light shielding film 22 is between the lower surface 10d of the semiconductor substrate 10 and the upper end of the second light receiving element region 12, that is, the upper surface 10u of the semiconductor substrate 10. Same as distance. There is no step between the second light shielding film 22 and the upper surface 10 u of the semiconductor substrate 10. A flat surface is formed by the upper surface 22 u of the second light shielding film 22 and the upper surface 10 u of the semiconductor substrate 10 adjacent to the second light shielding film 22.

  In addition, the solid-state imaging device 1 includes a third resin layer 33 and a third lens 43. The third resin layer 33 is, for example, a color filter layer that preferentially transmits red light. The semiconductor substrate 10 further includes a third light receiving element region 13 aligned with the second light receiving element region 12 in the Y direction. The third light receiving element region 13 includes a photoelectric conversion element that generates a signal charge according to the amount of light incident on the third light receiving element region 13 through the third lens 43. This photoelectric conversion element is a Si photodiode.

  The third resin layer 33 is provided on the third light receiving element region 13. The third lens 43 is provided on the third resin layer 33. The focal point f3 of the third lens 43 is located on the upper surface 10u of the semiconductor substrate 10. The third lens 43 includes, for example, at least one of acrylic resin, epoxy resin, polystyrene resin, polycarbonate resin, and the like.

  The heights of the first resin layer 31, the second resin layer 32, and the third resin layer 33 from the upper surface 10u of the semiconductor substrate 10 are the same. The focal length of the first lens 41, the focal length of the second lens 42, and the focal length of the third lens 43 are the same.

  The solid-state imaging device 1 includes a metal layer 23, a metal layer 24, a metal layer 25, a metal layer 26, and an insulating layer 53. Each of the metal layer 23, the metal layer 24, the metal layer 25, and the metal layer 26 includes the same material as that of the first light shielding film 21 or the second light shielding film 22. The insulating layer 53 includes, for example, silicon oxide.

  The solid-state imaging device 1 includes light-receiving element regions 14 and 15 including photodiodes, resin layers 34 and 35, and lenses 44 and 45. In FIG. 1A, each of the light receiving element regions 14 and 15, the resin layers 34 and 35, and the lenses 44 and 45 has a half cross section. The resin layer 34 is, for example, a color filter layer that preferentially transmits red light. The resin layer 35 is, for example, a color filter layer that preferentially transmits green light.

  The metal layer 23 is connected to the first light shielding film 21. The metal layer 25 is connected to the second light shielding film 22. In the Y direction, the metal layer 24 and the insulating layer 53 are provided between the first resin layer 31 and the second resin layer 32. In the Y direction, a metal layer 23 and an insulating layer 53 are provided between the resin layer 34 and the first resin layer 31. In the Y direction, a metal layer 25 and an insulating layer 53 are provided between the second resin layer 32 and the third resin layer 33. In the Y direction, a metal layer 26 and an insulating layer 53 are provided between the third resin layer 33 and the resin layer 35. The insulating layer 53 surrounds each of the first resin layer 31, the second resin layer 32, and the third resin layer 33 in the XY plane.

  In addition, in the solid-state imaging device 1, a plurality of light receiving element regions other than the light receiving element regions 11 to 15 are arranged two-dimensionally (X direction and Y direction) on the upper surface 10 u of the semiconductor substrate 10. A color filter layer is provided on each of the plurality of light receiving element regions. Here, the color filter layer is a color filter layer that preferentially transmits one of red light, green light, and blue light. Further, a lens is provided on each of the plurality of light receiving element regions via a color filter layer.

  In FIG. 1B, nine pixels and six pixels on which a half plane is displayed are represented by a broken line extending in the X direction and a broken line extending in the Y direction. The first light shielding film 21 covers substantially half of the first light receiving element region 11. The second light shielding film 22 covers substantially half of the second light receiving element region 12. The external shape of the 1st light shielding film 21 and the 2nd light shielding film 22 is a rectangle, for example.

  The pixel on which the first light shielding film 21 or the second light shielding film 22 is disposed is a phase difference detection pixel. In the present embodiment, the left-side phase difference detection pixel as shown in FIG. 1B is the left pixel 1PL, and the right-side phase difference detection pixel is the right pixel 1PR. Pixels other than the left pixel 1PL and the right pixel 1PR function as image sensor pixels. The phase difference detection pixels are not limited to one set of the left pixel 1PL and the right pixel 1PR, and a plurality of sets may be arranged on the semiconductor substrate 10.

  Before describing the operation of the solid-state imaging device 1, the operation of the solid-state imaging device 100 according to the first reference example will be described.

  FIG. 2A is a schematic cross-sectional view illustrating a solid-state imaging device according to a first reference example and a schematic diagram illustrating a camera according to the first reference example. FIG. 2B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the first reference example.

  In the solid-state imaging device 100 according to the first reference example, no step is formed on the upper surface 10 u of the semiconductor substrate 10 in the region where the first light receiving element region 11 is provided. Further, no step is formed on the upper surface 10 u of the semiconductor substrate 10 in the region where the second light receiving element region 12 is provided.

  In the solid-state imaging device 100, there is a step between the upper surface 21 u of the first light shielding film 21 and the upper surface 10 u of the semiconductor substrate 10. Further, there is a step between the upper surface 22 u of the second light shielding film 22 and the upper surface 10 u of the semiconductor substrate 10. In the solid-state imaging device 100, the first light shielding film 21 and the second light shielding film 22 are provided on the upper surface 10 u of the flat semiconductor substrate 10.

  In the solid-state imaging device 100, the focal point of the first lens 41 and the focal point of the second lens 42 are located on the upper surface 10 u of the semiconductor substrate 10. The solid-state imaging device 100 is incorporated in an image sensor 202 provided in the camera 200, for example. For example, in the image sensor 202, a plurality of solid-state imaging elements 100 are periodically arranged in the XY plane. The image sensor 202 faces the camera lens 201.

  When attention is paid to the pixel provided with the first light shielding film 21 and the second light shielding film 22, the left pixel in FIG. 2A is the left pixel 100PL, and the right pixel is the right pixel 100PR. .

  For example, when the focal point 201f of the camera lens 201 is positioned in front of the image sensor 202 and the light beam Pf1 is incident on one of the solid-state imaging elements 100 through the camera lens 201 (front focus), the solid-state imaging element 100 The first lens 41 and the second lens 42 are incident with a light flux Pf1 tilted to the right from the normal C1 with respect to the semiconductor substrate 10.

  FIG. 2B shows the relationship between the incident angle (θ) and the light intensity (a.u.:arbitrary unit) of the signal charge. Here, the value obtained by integrating the light intensity on the vertical axis at the incident angle (θ) on the horizontal axis corresponds to the light intensity received by the plurality of solid-state imaging devices 100. In addition, the absolute value of the incident angle (θ) increases as the position of the solid-state imaging device 100 is further away from the center 202c of the image sensor 202. Further, 30 ° is a critical angle of the light beam incident on the first lens 41 and the second lens 42.

  For example, in the left pixel 100PL, the light intensity is highest when the light beam Pf1 is incident perpendicularly (θ: 0 °) with respect to the semiconductor substrate 10. However, in the left pixel 100PL, the light beam Pf1 hits the first light shielding film 21 when the light beam Pf1 is tilted to the right even a little. Thereby, in the left pixel 100PL, as the absolute value of the incident angle (θ) increases, the light intensity attenuates. This is depicted as curve A.

  On the other hand, in the right pixel 100PR, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the left pixel 100PL. In the right pixel 100PR, even if the light beam Pf1 is slightly tilted to the right, the light beam Pf1 strikes the second light receiving element region 12. That is, the light intensity of the right pixel 100PR is higher than the light intensity of the left pixel 100PL. In the right pixel 100PR, as the absolute value of the incident angle (θ) increases, the light intensity temporarily reaches a maximum. Then, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is depicted as curve B.

  However, in the first reference example, the focal point of the second lens 42 is located at the upper end of the second light receiving element region 12. Thereby, in the right pixel 100PR, a part of the light flux Pf1 is blocked by the second light shielding film 22. For example, FIG. 2A shows a state in which a part of the light flux Pf1 is reflected by the second light shielding film 22.

  Next, a state in which the focal point 201f of the camera lens 201 is positioned behind the image sensor 202 and the light beam Pf1 is incident on the solid-state imaging device 100 through the camera lens 201 (back focus) will be described. FIG. 3A is a schematic cross-sectional view showing a solid-state imaging device according to a first reference example and a schematic view showing a camera according to the first reference example. FIG. 3B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the first reference example.

  For example, when the focal point 201f of the camera lens 201 is positioned behind the image sensor 202 and the light beam Pf1 is incident on one of the solid-state imaging devices 100 through the camera lens 201), the first lens 41 and the first lens 41 of the solid-state imaging device 100 are used. A light flux Pf1 tilted to the left from the normal line C1 with respect to the semiconductor substrate 10 is incident on the two lenses 42.

  FIG. 3B shows the relationship between the incident angle (θ) and the light intensity (a.u.:arbitrary unit) of the signal charge. Here, the value obtained by integrating the light intensity on the vertical axis at the incident angle (θ) on the horizontal axis corresponds to the light intensity received by the plurality of solid-state imaging devices 100. In addition, the absolute value of the incident angle (θ) increases as the position of the solid-state imaging device 100 is further away from the center 202c of the image sensor 202. Here, −30 ° is the critical angle of the light beam incident on the first lens 41 and the second lens 42. An angle tilted to the right is represented by a positive value, and an angle tilted to the left is represented by a negative value. In FIG. 3B, the result of the solid-state imaging device 100 described above is also displayed in an overlapping manner.

  For example, in the right pixel 100PR, the light intensity is highest when the light flux Pf1 is incident perpendicularly (θ: 0 °) to the semiconductor substrate 10. However, in the right pixel 100PR, if the light beam Pf1 is tilted to the left even a little, the light beam Pf1 hits the second light shielding film 22. Thereby, in the right pixel 100PR, the light intensity attenuates as the absolute value of the incident angle (θ) increases. This is depicted as curve B.

  On the other hand, in the left pixel 100PL, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the right pixel 100PR. In the left pixel 100PL, the light beam Pf1 strikes the first light receiving element region 11 even if the light beam Pf1 is slightly tilted to the left. That is, the light intensity of the left pixel 100PL is higher than the light intensity of the right pixel 100PR. In the left pixel 100PL, as the absolute value of the incident angle (−θ) increases, the light intensity temporarily reaches a maximum. Thereafter, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is depicted as curve A.

  However, in the first reference example, the focal point of the first lens 41 is located at the upper end of the first light receiving element region 11. Thereby, in the left pixel 100PL, a part of the light flux Pf1 is blocked by the first light shielding film 21. For example, FIG. 3A shows a state in which a part of the light beam Pf1 is reflected by the first light shielding film 21.

  When the data of the relationship between the incident angle (θ) and the light intensity is acquired and the light intensity obtained by integrating the light intensity at the incident angle (θ) becomes the same in the right pixel 100PR and the left pixel 100PL, the camera lens 201 is used. Is in focus on the image sensor 202.

  FIG. 4A is a schematic cross-sectional view illustrating a solid-state imaging device according to a second reference example and a schematic diagram illustrating a camera according to the second reference example. FIG. 4B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the second reference example.

  In the example shown in FIGS. 4A and 4B, in the solid-state imaging device 101, the focus of the first lens 41 is located on the upper surface 21u of the first light shielding film 21, and the focus of the second lens 42 is the second. It is located on the upper surface 22 u of the light shielding film 22. Other configurations of the solid-state imaging device 101 are the same as the configurations of the solid-state imaging device 100. The solid-state image sensor 101 is incorporated in an image sensor 202 provided in the camera 200, for example. In the image sensor 202, for example, a plurality of solid-state imaging elements 101 are periodically arranged in the XY plane.

  For example, when the focal point 201f of the camera lens 201 is positioned in front of the image sensor 202, the first lens 41 and the second lens 42 of any one of the solid-state imaging devices 101 are tilted to the right from the normal line C1 with respect to the semiconductor substrate 10. The incident light beam Pf1 enters.

  FIG. 4B shows the relationship between the incident angle (θ) and the light intensity (a.u.) of the signal charge. The value obtained by integrating the light intensity on the vertical axis at the incident angle (θ) on the horizontal axis corresponds to the light intensity received by the plurality of solid-state imaging devices 101. In addition, the absolute value of the incident angle (θ) increases as the position of the solid-state imaging device 101 is further away from the center 202 c of the image sensor 202. In FIG. 4B, the result of the solid-state imaging device 100 described above is also displayed in an overlapping manner.

  For example, in the left pixel 101PL, the light intensity is highest when the light flux Pf1 is incident on the semiconductor substrate 10 perpendicularly (θ: 0 °). However, in the left pixel 101PL, the light beam Pf1 hits the first light shielding film 21 when the light beam Pf1 is tilted to the right even a little. Thereby, in the left pixel 101PL, the light intensity attenuates as the absolute value of the incident angle (θ) increases. This is depicted as curve C.

  On the other hand, in the right pixel 101PR, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the left pixel 101PL. In the right pixel 101PR, even if the light beam Pf1 is slightly tilted to the right, the light beam Pf1 strikes the second light receiving element region 12. That is, the light intensity of the right pixel 101PR is higher than the light intensity of the left pixel 101PL. In the right pixel 101PR, as the absolute value of the incident angle (θ) increases, the light intensity temporarily reaches a maximum. After that, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is depicted as curve D.

  In the second reference example, the focal point of the second lens 42 is located on the upper surface 22 u of the second light shielding film 22. Thus, the light beam Pf1 that has reached the second resin layer 32 through the second lens 42 passes between the second light shielding film 22 and the metal layer 24 and reaches the second light receiving element region 12.

  However, in the right pixel 101PR, a part of the light flux Pf1 hits the corner 22c of the second light shielding film 22, and a part of the light flux Pf1 is blocked by the corner 22c. Further, when the upper surface of the second light shielding film 22 is focused, the focus of the pixels other than the phase difference detection pixels is shifted from the upper surface of the light receiving element, and the light intensity received by the light receiving element region is reduced.

  Next, in the second reference example, a state where the focal point 201f of the camera lens 201 is positioned behind the image sensor 202 will be described. FIG. 5A is a schematic cross-sectional view illustrating a solid-state imaging device according to a second reference example and a schematic diagram illustrating a camera according to the second reference example. FIG. 5B is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the second reference example.

  For example, when the focal point 201f of the camera lens 201 is positioned behind the image sensor 202, the first lens 41 and the second lens 42 of any one of the solid-state imaging devices 101 are tilted to the left from the normal line C1 with respect to the semiconductor substrate 10. The light beam Pf1 enters.

  FIG. 5B shows the relationship between the incident angle (θ) and the light intensity (a.u.) of the signal charge. The value obtained by integrating the light intensity on the vertical axis at the incident angle (θ) on the horizontal axis corresponds to the light intensity received by the plurality of solid-state imaging devices 101. In addition, the absolute value of the incident angle (θ) increases as the position of the solid-state imaging device 101 is further away from the center 202 c of the image sensor 202.

  For example, in the right pixel 101PR, the light intensity is highest when the light flux Pf1 is incident perpendicularly (θ: 0 °) to the semiconductor substrate 10. However, in the right pixel 101PR, the light beam Pf1 hits the second light shielding film 22 if the light beam Pf1 is tilted to the left even a little. Thereby, in the right pixel 101PR, the light intensity attenuates as the absolute value of the incident angle (θ) increases. This state is represented as a curve D.

  On the other hand, in the left pixel 101PL, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the right pixel 101PR. In the left pixel 101PL, the light beam Pf1 strikes the first light receiving element region 11 even if the light beam Pf1 is slightly tilted to the left. That is, the light intensity of the left pixel 101PL is higher than the light intensity of the right pixel 101PR. In the left pixel 101PL, as the absolute value of the incident angle (θ) increases, the light intensity temporarily reaches a maximum. After that, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is depicted as curve C.

  In the second reference example, the focal point of the first lens 41 is located on the upper surface 21 u of the first light shielding film 21. As a result, the light beam Pf1 that has reached the first resin layer 31 through the first lens 41 passes between the first light shielding film 21 and the metal layer 24 and reaches the first light receiving element region 11.

  However, in the left pixel 101PL, a part of the light flux Pf1 hits the corner 21c of the first light shielding film 21, and a part of the light flux Pf1 is blocked by the corner 21c. Further, when the upper surface of the first light shielding film 21 is in focus, the focus of the pixels other than the phase difference detection pixels is shifted from the upper surface of the light receiving element, and the light intensity received by the light receiving element region is reduced.

  The operation of the solid-state imaging device 1 according to this embodiment will be described.

  FIG. 6 is a schematic cross-sectional view illustrating the solid-state imaging device according to the present embodiment and a schematic diagram illustrating the camera according to the present embodiment. FIG. 7 is a schematic cross-sectional view illustrating a solid-state imaging device according to the present embodiment and a schematic diagram illustrating a camera according to the present embodiment. FIG. 8 is a graph showing the relationship between the incident angle of light and the light intensity of the light receiving element region in the solid-state imaging device according to the present embodiment. In FIG. 8, the value obtained by integrating the light intensity on the vertical axis at the incident angle (θ) on the horizontal axis corresponds to the light intensity received by the plurality of solid-state imaging devices 1. In addition, the absolute value of the incident angle (θ) increases as the position of the solid-state imaging device 1 is further away from the center 202c of the image sensor 202. In FIG. 8, the results of the solid-state imaging devices 100 and 101 described above are also displayed in an overlapping manner.

  For example, the solid-state imaging device 1 is incorporated in an image sensor 202 provided in the camera 200. For example, in the image sensor 202, a plurality of solid-state imaging devices 1 are periodically arranged in the XY plane.

  The operation when the light beam Pf1 enters one of the solid-state imaging devices 1 from the right side will be described.

  For example, as shown in FIG. 6, the focal point 201 f of the camera lens 201 is positioned in front of the image sensor 202. As a result, the light flux Pf1 tilted to the right from the normal line C1 with respect to the semiconductor substrate 10 enters the first lens 41 and the second lens 42 of the solid-state imaging device 1.

  For example, in the left pixel 1PL, the light intensity is highest when the light beam Pf1 is incident perpendicularly (θ: 0 °) to the semiconductor substrate 10. However, in the left pixel 1PL, the light beam Pf1 hits the first light shielding film 21 when the light beam Pf1 is tilted to the right even a little. Thereby, in the left pixel 1PL, the light intensity attenuates as the absolute value of the incident angle (θ) increases. This is illustrated as a curve α in FIG.

  On the other hand, in the right pixel 1PR, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the left pixel 1PL. In the right pixel 1PR, even if the light beam Pf1 is slightly tilted to the right, the light beam Pf1 strikes the second light receiving element region 12. That is, the light intensity of the right pixel 1PR is higher than the light intensity of the left pixel 1PL. In the right pixel 1PR, as the absolute value of the incident angle (θ) increases, the light intensity temporarily reaches a maximum. Then, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is depicted as a curve β in FIG.

  The operation when the light beam Pf1 is incident on the solid-state imaging device 1 from the left side will be described.

  For example, as shown in FIG. 7, the focal point 201 f of the camera lens 201 is located behind the image sensor 202. As a result, the light flux Pf1 tilted to the left from the normal line C1 with respect to the semiconductor substrate 10 enters the first lens 41 and the second lens 42 of any one of the solid-state imaging devices 1.

  For example, in the right pixel 1PR, the light intensity is highest when the light beam Pf1 is incident perpendicularly (θ: 0 °) to the semiconductor substrate 10. However, in the right pixel 1PR, the light beam Pf1 hits the second light shielding film 22 if the light beam Pf1 is tilted to the left even a little. Thereby, in the right pixel 1PR, the light intensity attenuates as the absolute value of the incident angle (θ) increases. This is depicted as a curve β in FIG.

  On the other hand, in the left pixel 1PL, when the incident angle (θ) of the light beam Pf1 is vertical (θ: 0 °), the light intensity is the same as that of the right pixel 1PR. In the left pixel 1PL, the light beam Pf1 strikes the first light receiving element region 11 even if the light beam Pf1 is slightly tilted to the left. That is, the light intensity of the left pixel 1PL is higher than the light intensity of the right pixel 1PR. In the left pixel 1PL, as the absolute value of the incident angle (θ) increases, the light intensity temporarily reaches a maximum. After that, the incident angle (θ) approaches the critical angle, and the light intensity is eventually attenuated. This is illustrated as a curve α in FIG.

  In the present embodiment, there is no step between the fourth surface 10-4 of the second light receiving element region 12 and the upper surface 22 u of the second light shielding film 22. Accordingly, in the present embodiment, a phenomenon (first reference example) in which a part of the light flux Pf1 is blocked by the second light shielding film 22 is less likely to occur. Further, there is no step between the second surface 10-4 of the first light receiving element region 11 and the upper surface 21 u of the first light shielding film 21. Accordingly, in the present embodiment, a phenomenon (first reference example) in which a part of the light beam Pf1 is blocked by the first light shielding film 22 is less likely to occur. Thereby, in this embodiment, the sensitivity of a signal charge increases compared with the first reference example.

  Further, when there is no step between the fourth surface 10-4 of the second light receiving element region 12 and the upper surface 22u of the second light shielding film 22, a part of the light flux Pf1 is caused by the corner portion 22c of the second light shielding film 22. The obstructed phenomenon (second reference example) is difficult to occur. Further, when there is no step between the second surface 10-2 of the first light receiving element region 11 and the upper surface 21u of the first light shielding film 21, a part of the light flux Pf1 is caused by the corner portion 21c of the first light shielding film 21. The obstructed phenomenon (second reference example) is difficult to occur.

  In the present embodiment, the focal point of the second lens 42 is located on the upper surface 10 u of the semiconductor substrate 10. Thereby, in this embodiment, the focus of the 2nd lens 42 approaches the pn junction of the 2nd light receiving element area | region 12 compared with a 2nd reference example. In the present embodiment, the focal point of the first lens 41 is located on the upper surface 10 u of the semiconductor substrate 10. Thereby, in this embodiment, the focus of the 1st lens 41 approaches the pn junction of the 1st light receiving element area | region 11 compared with a 1st reference example. Thereby, in this embodiment, the sensitivity of the signal charge is further increased as compared with the second reference example. That is, it is possible to achieve both improvement of the phase difference detection characteristics and improvement of the light intensity received by the light receiving region of the pixel that is not the phase difference detection pixel.

  Thereby, in this embodiment, the characteristic of a phase difference detection improves compared with a reference example.

  Further, in the present embodiment, the focal points of the lenses (first lens 41 and second lens 42) arranged in the phase difference detection pixels (left pixel 1PL, right pixel 1PR) are located on the upper surface 10u of the semiconductor substrate 10. ing. Further, the focal point of the third lens 43 disposed in the pixel for the image sensor is also located on the upper surface 10 u of the semiconductor substrate 10. Thereby, the manufacturing process which selectively changes only the focus of the 1st lens 41 and the focus of the 2nd lens 42 in the solid-state image sensor 1 becomes unnecessary.

  In the present embodiment, the first resin layer 31 is provided on the first light shielding film 21 and the first light receiving element region 11. When the refractive index of the first resin layer 31 is the same as the refractive index of the first lens 41, the light incident from the first lens 41 is not reflected by the interface between the first resin layer 31 and the first lens 41. It reaches the first light receiving element region 11. A second resin layer 32 is provided on the second light shielding film 22 and the second light receiving element region 12. When the refractive index of the second resin layer 32 is the same as the refractive index of the second lens 42, the light incident from the second lens 42 is not reflected by the interface between the second resin layer 32 and the second lens 42. It reaches the second light receiving element region 12.

  In the present embodiment, each of the first resin layer 31 and the second resin layer 32 is surrounded by the insulating layer 53. The refractive index of the insulating layer 53 may be different from the refractive index of the first resin layer 31 and the refractive index of the second resin layer 32. For example, when the refractive index of the insulating layer 53 is lower than the refractive index of the first resin layer 31 and the refractive index of the second resin layer 32, the interface between the first resin layer 31 and the insulating layer 53 and the second resin layer 32 Light reflection (for example, total reflection) easily occurs at the interface with the insulating layer 53. Thereby, light collection in the first light receiving element region 11 and the second light receiving element region 12 is promoted.

  In addition, metal layers 23, 24, and 25 are provided under the insulating layer 53. Light is also reflected by the metal layers 23, 24, and 25, and light collection in the first light receiving element region 11 and the second light receiving element region 12 is promoted.

  The first resin layer 31 or the second resin layer 32 may be a color filter layer. For example, if the first resin layer 31 or the second resin layer 32 is a color filter layer, light in a specific wavelength band is transmitted through the first resin layer 31 or the second resin layer 32.

  Thereby, the positional deviation of the focal point f1 in the first lens 41 due to chromatic aberration and the positional deviation of the focal point f2 in the second lens 42 due to chromatic aberration are suppressed.

  In the above embodiment, “above” when expressed as “A is provided on B” means that A is in contact with B and A is provided on B. In addition to the case, it may be used to mean that A does not contact B and A is provided above B. “A is provided on B” is also applied when A and B are reversed and A is positioned below B, or when A and B are arranged side by side. There is a case. This is because even if the semiconductor device according to the embodiment is rotated, the structure of the semiconductor device is not changed before and after the rotation.

  The embodiment has been described above with reference to specific examples. However, the embodiments are not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the embodiments as long as they include the features of the embodiments. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

  In addition, each element included in each of the above-described embodiments can be combined as long as technically possible, and combinations thereof are also included in the scope of the embodiment as long as they include the features of the embodiment. In addition, in the category of the idea of the embodiment, those skilled in the art can conceive various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the embodiment. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1,100,101 Solid-state image sensor, 1PL Left pixel, 1PR Right pixel, 10 Semiconductor substrate, 10-1 1st surface, 10-2 2nd surface, 10-3 3rd surface, 10-4 4th surface, 10d Bottom surface, 10u top surface, 11 first light receiving element region, 11a part, 12 second light receiving element region, 12a part, 13 third light receiving element region, 14, 15 light receiving element region, 21 first light shielding film, 21c corner 21d lower surface, 21u upper surface, 22 second light shielding film, 22c corner, 22d lower surface, 22u upper surface, 23, 24, 25, 26 metal layer, 31 first resin layer, 32 second resin layer, 33 third resin layer , 34, 35 Resin layer, 41 First lens, 42 Second lens, 43 Third lens, 44, 45 lens, 53 Insulating layer, 100PL, 101PL Left pixel, 100PR, 101PR Right pixel, 2 0 camera, 201 camera lens, 201f focus, 202 image sensor, C1 normal, Pf1 light beam, f1, f2, f3 the focal

Claims (5)

A semiconductor substrate having an upper surface and a lower surface, wherein a first light receiving element region and a second light receiving element region are provided from the upper surface toward the lower surface, and the second light receiving element region is provided in the first light receiving element region. A line of semiconductor substrates,
A first light-shielding film selectively provided on the first light-receiving element region;
A first resin layer provided on the first light receiving element region and on the first light shielding film;
A first lens provided on the first resin layer;
A second light-shielding film selectively provided on the second light-receiving element region;
A second resin layer provided on the second light receiving element region and on the second light shielding film;
A second lens provided on the second resin layer;
With
In the region where the first light receiving element region is provided, the upper surface of the semiconductor substrate includes a first surface on which the first light shielding film is provided and a second surface on which the first light shielding film is not provided. Including
A distance between the lower surface of the semiconductor substrate and the first surface is shorter than a distance between the lower surface of the semiconductor substrate and the second surface;
In the region in which the second light receiving element region is provided, the upper surface of the semiconductor substrate includes a third surface on which the second light shielding film is provided and a fourth surface on which the second light shielding film is not provided. Including
The distance between the lower surface of the semiconductor substrate and the third surface is shorter than the distance between the lower surface of the semiconductor substrate and the fourth surface,
In the direction from the first light receiving element region to the second light receiving element region, the second surface is located between the first light shielding film and the fourth surface, and the fourth surface is the second light receiving region. A solid-state imaging device positioned between a surface and the second light shielding film. There is no step between the upper surface of the first light shielding film and the second surface,
The solid-state imaging device according to claim 1, wherein there is no step between the upper surface of the second light shielding film and the fourth surface.   3. The solid-state imaging device according to claim 1, wherein a focal point of the first lens and a focal point of the second lens are located on the upper surface of the semiconductor substrate. An insulating layer surrounding the first resin layer and the second resin layer;
4. The solid-state imaging device according to claim 1, wherein a refractive index of the insulating layer is different from a refractive index of the first resin layer and a refractive index of the second resin layer. The refractive index of the first resin layer is the same as the refractive index of the first lens,
5. The solid-state imaging device according to claim 1, wherein a refractive index of the second resin layer is the same as a refractive index of the second lens.