Image sensor

Abstract

An imaging element according to an aspect of the present disclosure is provided with a semiconductor substrate and a plurality of pixels. Each of the plurality of pixels includes: a first photoelectric conversion layer; a first pixel electrode; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer; a second pixel electrode; and a second plug electrically connecting the semiconductor substrate and the second pixel electrode. When viewed from a direction normal to the semiconductor substrate, in a first pixel and a plurality of second pixels adjacent to the first pixels among the plurality of pixels, a distance between those plugs among the first plug and the second plugs that are closest to each other is not less than 1 / 2 a pixel pitch.

Description

[Technical field]

[0001] The present disclosure relates to an imaging device. [Background technology]

[0002] Conventionally, imaging elements that utilize photoelectric conversion have been widely used.

[0003] Patent Document 1 discloses an imaging element having a plurality of photoelectric conversion films. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-268471 A Summary of the Invention [Problem to be solved by the invention]

[0005] One challenge for imaging devices is to improve image quality. [Means for solving the problem]

[0006] An imaging element according to one aspect of the present disclosure includes: A semiconductor substrate; A plurality of pixels; Equipped with. Each of the plurality of pixels is a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate, the second photoelectric conversion layer converting light into a second charge; a second pixel electrode that collects the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Includes. The plurality of pixels includes a first pixel and a plurality of second pixels adjacent to the first pixel. When viewed from a normal direction of the semiconductor substrate, in the first pixel and the plurality of second pixels, the distance between the closest of the first plug and the closest of the second plugs is equal to or greater than 1 / 2 of the pixel pitch, which is the shortest distance between the center of the first pixel and the center of each of the plurality of second pixels. Effect of the Invention

[0007] According to the techniques of the present disclosure, image quality can be improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of an imaging device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view of the imaging element shown in FIG. [Figure 3A] FIG. 3A is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the first embodiment is viewed from the normal direction of a semiconductor substrate. [Figure 3B] FIG. 3B is a diagram showing the arrangement of pixel electrodes and plugs in a particular pixel. [Figure 4A] FIG. 4A is a diagram showing an arrangement of pixel electrodes and plugs according to Modification 1. FIG. [Figure 4B] FIG. 4B is a diagram showing an arrangement of pixel electrodes and plugs in a particular pixel of Modification 1. In FIG. [Figure 4C] FIG. 4C is a diagram showing another arrangement of pixel electrodes and plugs in a particular pixel of the first modification example. [Figure 5A] FIG. 5A is a diagram showing an arrangement of pixel electrodes and plugs according to Modification 2. In FIG. [Figure 5B] FIG. 5B is a diagram showing an arrangement of pixel electrodes and plugs in a specific pixel of Modification 2. In FIG. [Figure 6A] FIG. 6A is a diagram showing an arrangement of pixel electrodes and plugs according to Modification 3. In FIG. [Figure 6B]FIG. 6B is a diagram showing an arrangement of pixel electrodes and plugs in a specific pixel of Modification 3. In FIG. [Figure 7A] FIG. 7A is a diagram showing an arrangement of pixel electrodes and plugs according to Modification 4. In FIG. [Figure 7B] FIG. 7B is a diagram showing an arrangement of pixel electrodes and plugs in a specific pixel in Modification 4. In FIG. [Figure 8A] FIG. 8A is a configuration diagram of an imaging element according to a second embodiment of the present disclosure. [Figure 8B] FIG. 8B is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the second embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 8C] FIG. 8C is a diagram showing the arrangement of pixel electrodes and plugs in a particular pixel. [Figure 9A] FIG. 9A is a diagram showing an arrangement of pixel electrodes and plugs according to Modification 5. In FIG. [Figure 9B] FIG. 9B is a diagram showing an arrangement of pixel electrodes and plugs in a specific pixel in Modification 5. In FIG. [Figure 10A] FIG. 10A is a configuration diagram of an imaging element according to a third embodiment of the present disclosure. [Figure 10B] FIG. 10B is a diagram showing the arrangement of pixel electrodes and plugs when the imaging element according to the third embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 10C] FIG. 10C is a diagram showing the arrangement of pixel electrodes and plugs in a particular pixel. [Figure 11A] FIG. 11A is a cross-sectional view of an imaging element according to a fourth embodiment of the present disclosure. [Figure 11B] FIG. 11B is a diagram showing the arrangement of pixel electrodes, plugs, and photodiodes when the imaging element according to the fourth embodiment is viewed from the normal direction of the semiconductor substrate. [Figure 12] FIG. 12 is a diagram showing an arrangement of pixel electrodes and plugs in a particular pixel of an imaging element according to the fifth embodiment of the present disclosure. [Figure 13A] FIG. 13A is a plan view of a regular hexagonal pixel electrode. [Figure 13B]FIG. 13B is a plan view of a regular octagonal pixel electrode. [Figure 14] FIG. 14 is a cross-sectional view of an imaging element according to the sixth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Findings on which this disclosure is based) The image sensor has, for example, a semiconductor substrate and a photoelectric conversion film disposed thereover. In recent years, in order to further increase the density of pixels, an image sensor having a stacked structure of a plurality of photoelectric conversion films has been proposed, as disclosed in Patent Document 1.

[0010] The present inventors have investigated the causes of impeding improvements in the image quality of image sensors, and have found the following problems.

[0011] The imaging element has plugs that connect pixel electrodes and a semiconductor substrate. As pixels become denser, crosstalk between the plugs becomes evident. Crosstalk between the plugs causes color mixing in the image to be obtained. For example, when crosstalk occurs between plugs corresponding to different colors, such as R (red) and G (green), G and B (blue), or B and R, the difference in color between the subject and the obtained image becomes noticeable. Suppressing crosstalk between the plugs is beneficial for improving image quality.

[0012] It is predicted that crosstalk between plugs will become evident in an imaging element having the structure disclosed in Patent Document 1.

[0013] The present disclosure provides techniques for suppressing crosstalk between plugs.

[0014] (Summary of one aspect of the present disclosure) The imaging element according to the first aspect of the present disclosure includes: A semiconductor substrate; A plurality of pixels; Equipped with. Each of the plurality of pixels is a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate, the second photoelectric conversion layer converting light into a second charge; a second pixel electrode that collects the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Includes. The plurality of pixels includes a first pixel and a plurality of second pixels adjacent to the first pixel. When viewed from a normal direction of the semiconductor substrate, in the first pixel and the plurality of second pixels, the distance between the closest of the first plug and the closest of the second plugs is equal to or greater than 1 / 2 of the pixel pitch, which is the shortest distance between the center of the first pixel and the center of each of the plurality of second pixels.

[0015] According to the first aspect, since the plugs are sufficiently separated from each other in the first pixel and the second pixels adjacent to the first pixel, crosstalk between the plugs in the first pixel and the second pixels adjacent to the first pixel can be suppressed, and as a result, color mixing in the image to be obtained can be suppressed.

[0016] The plurality of pixels are two-dimensionally arranged along a first direction and a second direction perpendicular to the first direction, The plurality of second pixels include a pixel adjacent to the first pixel in the first direction; a pixel adjacent to the first pixel in a direction opposite to the first direction; a pixel adjacent to the first pixel in the second direction; a pixel adjacent to the first pixel in a direction opposite to the second direction; a pixel adjacent to the first pixel in a third direction between the first direction and the second direction; a pixel adjacent to the first pixel in a direction opposite to the third direction; a pixel adjacent to the first pixel in a fourth direction perpendicular to the third direction; and A pixel adjacent to the first pixel in a direction opposite to the fourth direction may be included.

[0017] In the second aspect of the present disclosure, for example, in the imaging element according to the first aspect, the distance between the first plug and the second plug in each of the pixels may be equal to or greater than ½ of the pixel pitch when viewed from the normal direction of the semiconductor substrate. With this configuration, crosstalk between plugs in the pixels can be further suppressed.

[0018] In a third aspect of the present disclosure, for example, in the image sensor according to the first or second aspect, each of the pixels may further include a third photoelectric conversion layer disposed between the second photoelectric conversion layer and the semiconductor substrate, the third photoelectric conversion layer converting light into a third charge, a third pixel electrode collecting the third charge, and a third plug electrically connecting the semiconductor substrate and the third pixel electrode. The three-layer structure is suitable for forming a full-color image.

[0019] In a fourth aspect of the present disclosure, for example, in the imaging element according to the third aspect, the distance between the first plug and the third plug in each of the pixels may be equal to or greater than half the pixel pitch when viewed from the normal direction of the semiconductor substrate. With this configuration, crosstalk between plugs in the pixels can be further suppressed.

[0020] In a fifth aspect of the present disclosure, for example, in the imaging element according to the third or fourth aspect, the distance between the second plug and the third plug in each of the pixels may be equal to or greater than half the pixel pitch when viewed from the normal direction of the semiconductor substrate. With this configuration, crosstalk between plugs in pixels can be further suppressed.

[0021] In a sixth aspect of the present disclosure, for example, in the imaging element according to any one of the third to fifth aspects, when viewed from the normal direction of the semiconductor substrate, in each of the plurality of pixels, the distance between the first plug and the second plug may be longer than the distance between the first plug and the third plug and also longer than the distance between the second plug and the third plug. With this configuration, crosstalk can be more effectively suppressed.

[0022] In a seventh aspect of the present disclosure, for example, the imaging element according to any one of the first to sixth aspects may further include a shield electrode between the first pixel and each of the second pixels, the shield electrode being maintained at a constant potential. With this configuration, crosstalk between plugs in adjacent pixels can be further suppressed.

[0023] An imaging element according to an eighth aspect of the present disclosure includes: A semiconductor substrate; a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode that collects the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate, the second photoelectric conversion layer converting light into a second charge; a second pixel electrode that collects the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Equipped with the first pixel electrode has a long side and a short side, When viewed from a normal direction of the semiconductor substrate, the distance between the first plug and the second plug is longer than the long side of the first pixel electrode.

[0024] According to the eighth aspect, crosstalk due to coupling between the first plug and the second plug is suppressed in each pixel, and as a result, color mixing in the image to be obtained can be suppressed.

[0025] In a ninth aspect of the present disclosure, for example, the imaging element according to the eighth aspect may further include a third photoelectric conversion layer disposed between the second photoelectric conversion layer and the semiconductor substrate, converting light into a third charge, a third pixel electrode collecting the third charge, and a third plug electrically connecting the semiconductor substrate and the third pixel electrode. The three-layer structure is suitable for forming a full-color image.

[0026] In a tenth aspect of the present disclosure, for example, in the image sensor according to the ninth aspect, the third plug may be disposed in a central region that is a region including the center of gravity of the third pixel electrode. This configuration improves the design freedom of the charge storage region and the transistor connected to the third plug.

[0027] An imaging element according to an eleventh aspect of the present disclosure, A semiconductor substrate; a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode that collects the first charges; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate, the second photoelectric conversion layer converting light into a second charge; a second pixel electrode that collects the second charges; Equipped with the second pixel electrode has a plurality of sides; When viewed from a normal direction of the semiconductor substrate, the first pixel electrode and the second pixel electrode are arranged to be shifted from each other by ½ or more of the length of each of the multiple sides of the second pixel electrode.

[0028] According to the eleventh aspect, crosstalk between plugs or crosstalk between charge accumulation regions can be suppressed without providing a notch or a through hole in the second photoelectric conversion layer.

[0029] In a twelfth aspect of the present disclosure, for example, the imaging element according to the eleventh aspect may further include a first plug electrically connecting the semiconductor substrate and the first pixel electrode, and the first plug may be disposed in a central region including the center of gravity of the first pixel electrode. With this configuration, it is not necessary to provide a through hole in the second pixel electrode for passing the first plug therethrough.

[0030] In a thirteenth aspect of the present disclosure, for example, the imaging element according to the eleventh or twelfth aspect may further include a second plug that electrically connects the semiconductor substrate and the second pixel electrode.

[0031] In a fourteenth aspect of the present disclosure, for example, in the image sensor according to any one of the first to thirteenth aspects, the first plug and the second plug may be disposed at diagonal positions in the first pixel electrode. With this configuration, crosstalk between the plugs can be more effectively suppressed.

[0032] In a fifteenth aspect of the present disclosure, for example, in an imaging element relating to any one of the first to fourteenth aspects, the first pixel electrode may include a first storage electrode that accumulates the first charge in the first photoelectric conversion layer and a first readout electrode electrically connected to the semiconductor substrate via the first plug, and the second pixel electrode may include a second storage electrode that accumulates the second charge in the second photoelectric conversion layer and a second readout electrode electrically connected to the semiconductor substrate via the second plug.

[0033] An imaging element according to a sixteenth aspect of the present disclosure, A semiconductor substrate; A plurality of pixels; An imaging element comprising: Each of the plurality of pixels is A first photoelectric conversion layer; a first pixel electrode that collects charges generated in the first photoelectric conversion layer; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate; a second pixel electrode that collects charges generated in the second photoelectric conversion layer; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; having When the imaging element is viewed from a normal direction of the semiconductor substrate, the distance between the closest plugs in the adjacent pixels is equal to or greater than ½ of the pixel pitch.

[0034] According to the sixteenth aspect, since the plugs in adjacent pixels are sufficiently separated from each other, crosstalk between the plugs in adjacent pixels can be suppressed, and as a result, color mixing in the image to be obtained can be suppressed.

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0036] (First embodiment) 1 shows a configuration of an imaging device 100A according to a first embodiment of the present disclosure. The imaging device 100A includes an imaging element 100. The imaging element 100 includes a semiconductor substrate 1 and a plurality of pixels 10. The plurality of pixels 10 are provided on the semiconductor substrate 1. Each pixel 10 is supported by the semiconductor substrate 1. A portion of the pixel 10 may be formed by the semiconductor substrate 1.

[0037] The semiconductor substrate 1 can be a circuit board including various electronic circuits, and is made of, for example, a Si substrate.

[0038] Each pixel 10 includes a photoelectric conversion unit 12. The photoelectric conversion unit 12 generates positive and negative charges, typically hole-electron pairs, upon receiving incident light. The photoelectric conversion unit 12 includes at least one photoelectric conversion layer disposed above the semiconductor substrate 1. In FIG. 1, the photoelectric conversion units 12 of each pixel 10 are shown spatially separated from one another. However, this is merely for convenience of explanation. The photoelectric conversion units 12 of the multiple pixels 10 may be continuously disposed on the semiconductor substrate 1 without any gaps between them. In other words, the photoelectric conversion units 12 of adjacent pixels may be electrically connected to one another.

[0039] 1, the pixels 10 are arranged in a plurality of rows and a plurality of columns, i.e., m rows and n columns. m and n are, independently, integers of 1 or more. The pixels 10 are arranged, for example, two-dimensionally on the semiconductor substrate 1 to form an imaging region. When the imaging device 100A is viewed in a plan view, the imaging element 100 can be defined as a region in which a photoelectric conversion layer exists.

[0040] In pixels arranged in m rows and n columns, if the pixel in x row and y column is represented as (x,y), the pixels adjacent to (x,y) are represented as (x-1,y-1), (x,y-1), (x+1,y-1), (x-1,y), (x+1,y), (x-1,y+1), (x,y+1), (x+1,y+1), (x+1,y+1), where x is a natural number less than m and y is a natural number less than n.

[0041] The number and arrangement of the pixels 10 are not particularly limited. In Fig. 1, the center of each pixel 10 is located on a lattice point of a square lattice. A plurality of pixels 10 may be arranged so that the center of each pixel 10 is located on a lattice point of a triangular lattice, a hexagonal lattice, or the like. By arranging the pixels 10 one-dimensionally, the image sensor 100 can be used as a line sensor.

[0042] The imaging device 100A has peripheral circuits formed on a semiconductor substrate 1.

[0043] The peripheral circuits include a vertical scanning circuit 52 and a horizontal signal readout circuit 54. The peripheral circuits may additionally include a control circuit 56 and a voltage supply circuit 58. The peripheral circuits may further include a signal processing circuit, an output circuit, and the like. Each circuit is provided on the semiconductor substrate 1. A part of the peripheral circuits may be disposed on a substrate other than the semiconductor substrate 1 on which the pixels 10 are formed.

[0044] The vertical scanning circuit 52 is also called a row scanning circuit. An address signal line 44 is provided corresponding to each row of the pixels 10, and the address signal line 44 is connected to the vertical scanning circuit 52. The signal line provided corresponding to each row of the pixels 10 is not limited to the address signal line 44, and a plurality of types of signal lines can be connected to the vertical scanning circuit 52 for each row of the pixels 10. The horizontal signal readout circuit 54 is also called a column scanning circuit. A vertical signal line 45 is provided corresponding to each column of the pixels 10, and the vertical signal line 45 is connected to the horizontal signal readout circuit 54.

[0045] The control circuit 56 receives command data, a clock, and the like provided from outside the imaging device 100A to control the entire imaging device 100A. Typically, the control circuit 56 has a timing generator and supplies drive signals to the vertical scanning circuit 52, the horizontal signal read circuit 54, the voltage supply circuit 58, and the like. The control circuit 56 can be realized, for example, by a microcontroller including one or more processors. The functions of the control circuit 56 may be realized by a combination of a general-purpose processing circuit and software, or may be realized by hardware specialized for such processing.

[0046] The voltage supply circuit 58 supplies a predetermined voltage to each pixel 10 via the voltage line 48. The voltage supply circuit 58 is not limited to a specific power supply circuit, and may be a circuit that converts a voltage supplied from a power source such as a battery into a predetermined voltage, or may be a circuit that generates a predetermined voltage. The voltage supply circuit 58 may be a part of the above-mentioned vertical scanning circuit 52. These circuits that constitute the peripheral circuits may be arranged in a peripheral region R2 outside the image sensor 100.

[0047] FIG. 2 shows a cross section of the image sensor 100.

[0048] Each pixel 10 has a plurality of photoelectric conversion layers. The plurality of photoelectric conversion layers include a first photoelectric conversion layer 121, a second photoelectric conversion layer 122, and a third photoelectric conversion layer 123. The first photoelectric conversion layer 121 may be a single layer shared by the plurality of pixels 10. The second photoelectric conversion layer 122 may be a single layer shared by the plurality of pixels 10. The third photoelectric conversion layer 123 may be a single layer shared by the plurality of pixels 10. However, each of the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 may be divided for each pixel. "Shared by a plurality of pixels" means that it is shared between a specific pixel and at least one pixel adjacent to the specific pixel.

[0049] The first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 are made of a photoelectric conversion material. The photoelectric conversion material is typically an organic material.

[0050] The first photoelectric conversion layer 121 collects charges (first charges) corresponding to light in a first wavelength range. The second photoelectric conversion layer 122 collects charges (second charges) corresponding to light in a second wavelength range. The third photoelectric conversion layer 123 collects charges (third charges) corresponding to light in a third wavelength range. The first wavelength range is, for example, the wavelength range of blue light. The first photoelectric conversion layer 121 is made of a material sensitive to blue light. The second wavelength range is, for example, the wavelength range of green light. The second photoelectric conversion layer 122 is made of a material sensitive to green light. The third wavelength range is, for example, the wavelength range of red light. The third photoelectric conversion layer 123 is made of a material sensitive to red light.

[0051] In this embodiment, the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, the third photoelectric conversion layer 123, and the semiconductor substrate 1 are arranged in this order. In the normal direction of the semiconductor substrate 1, the second photoelectric conversion layer 122 is arranged between the first photoelectric conversion layer 121 and the semiconductor substrate 1. In the normal direction of the semiconductor substrate 1, the third photoelectric conversion layer 123 is arranged between the second photoelectric conversion layer 122 and the semiconductor substrate 1. The arrangement order of the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 is not limited to this order.

[0052] Each pixel 10 further has a plurality of pixel electrodes. The plurality of pixel electrodes include a first pixel electrode 13, a second pixel electrode 14, and a third pixel electrode 15. The first pixel electrode 13 is electrically connected to a first photoelectric conversion layer 121. The second pixel electrode 14 is electrically connected to a second photoelectric conversion layer 122. The third pixel electrode 15 is electrically connected to a third photoelectric conversion layer 123.

[0053] The first pixel electrode 13 and the second pixel electrode 14 are transparent electrodes that are translucent to visible light and / or near infrared light. The transparent electrodes are made of a transparent conductive oxide such as ITO (Indium Tin Oxide). The third pixel electrode 15 is a non-transparent electrode that is not translucent to visible light and / or near infrared light. Examples of materials for the non-transparent electrodes include metals, metal oxides, metal nitrides, conductive polysilicon, etc.

[0054] In this specification, "having light transmissivity" means that the transmittance of light in a specific wavelength range is 40% or more. The wavelength range of visible light is, for example, 400 nm to 780 nm. The wavelength range of near-infrared light is, for example, 780 nm to 2000 nm. The transmittance can be calculated by the method specified in Japanese Industrial Standard JIS R3106 (1998).

[0055] An insulating layer 8 is provided between the first pixel electrode 13 and the second pixel electrode 14. An insulating layer 9 is provided between the third pixel electrode 15 and the semiconductor substrate 1. The insulating layers 8 and 9 are made of an insulating material such as SiO2.

[0056] Each pixel 10 further has a plurality of counter electrodes. The plurality of counter electrodes include a first counter electrode 17 and a second counter electrode 18. The first counter electrode 17 and the second counter electrode 18 are each shared by a plurality of pixels 10. The first counter electrode 17 and the second counter electrode 18 are each a transparent electrode that is translucent to visible light and / or near-infrared light.

[0057] The first counter electrode 17 is provided corresponding to the first pixel electrode 13. The first photoelectric conversion layer 121 is sandwiched between the first counter electrode 17 and the first pixel electrode 13. The second counter electrode 18 is provided corresponding to the second pixel electrode 14 and the third pixel electrode 15. The second photoelectric conversion layer 122 is sandwiched between the second counter electrode 18 and the second pixel electrode 14. The third photoelectric conversion layer 123 is sandwiched between the second counter electrode 18 and the third pixel electrode 15. The first counter electrode 17 is electrically connected to the first photoelectric conversion layer 121. The second counter electrode 18 is electrically connected to the second photoelectric conversion layer 122. The second counter electrode 18 is electrically connected to the third photoelectric conversion layer 123.

[0058] In this embodiment, the second counter electrode 18 applies a voltage to both the second photoelectric conversion layer 122 and the third photoelectric conversion layer 123. However, the second counter electrode 18 may be configured to apply a voltage only to the second photoelectric conversion layer 122. In this case, a third counter electrode that applies a voltage to the third photoelectric conversion layer 123 may be provided.

[0059] Each pixel 10 may include a microlens. The microlenses may be arranged to form a surface of the image sensor 100. One or more microlenses may be arranged for each pixel 10. The microlenses may be arranged to focus light on an overlapping region between the first pixel electrode 13 and the second pixel electrode 14 when the image sensor 100 is viewed in plan.

[0060] Each pixel 10 further has a plurality of plugs. Each plug extends in a normal direction of the semiconductor substrate 1. The plurality of plugs include a first plug 31, a second plug 32, and a third plug 33. The first plug 31 electrically connects the semiconductor substrate 1 to the first pixel electrode 13. The second plug 32 electrically connects the semiconductor substrate 1 to the second pixel electrode 14. The third plug 33 electrically connects the semiconductor substrate 1 to the third pixel electrode 15.

[0061] The first plug 31, the second plug 32, and the third plug 33 are made of a conductive material, such as a metal, a metal oxide, a metal nitride, or conductive polysilicon.

[0062] The semiconductor substrate 1 has a plurality of charge storage regions. The charge storage regions may be parts of the pixels 10. Each charge storage region is an n-type or p-type impurity region. The plurality of charge storage regions include a first charge storage region 3, a second charge storage region 4, and a third charge storage region 5. The first plug 31 electrically connects the first charge storage region 3 to the first pixel electrode 13. The second plug 32 electrically connects the second charge storage region 4 to the second pixel electrode 14. The third plug 33 electrically connects the third charge storage region 5 to the third pixel electrode 15.

[0063] The semiconductor substrate 1 may have a number of transistors for reading out the charges stored in the first charge storage region 3, the second charge storage region 4 and the third charge storage region 5, and for resetting the stored charges.

[0064] The pixel electrode may be electrically connected to the charge storage region via a plug penetrating the semiconductor substrate and a wiring layer below the semiconductor substrate.

[0065] In this specification, "upper" and "lower" are defined based on the traveling direction of light. The side approaching the light incident surface is "upper", and the side away from the light incident surface is "lower".

[0066] When the imaging element 10 is irradiated with light, electron-hole pairs are generated in the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123.

[0067] For example, when a voltage is applied between the first counter electrode 17 and the first pixel electrode 13 so that the potential of the first counter electrode 17 exceeds the potential of the first pixel electrode 13, holes which are positive charges are collected in the first pixel electrode 13, and electrons which are negative charges are collected in the first counter electrode 17. The holes collected in the first pixel electrode 13 are accumulated in the first plug 31 and the first charge accumulation region 3.

[0068] When a voltage is applied between the second opposing electrode 18 and the second pixel electrode 14 so that the potential of the second opposing electrode 18 exceeds the potential of the second pixel electrode 14, holes which are positive charges are collected in the second pixel electrode 14, and electrons which are negative charges are collected in the second opposing electrode 18. The holes collected in the second pixel electrode 14 are accumulated in the second plug 32 and the second charge accumulation region 4.

[0069] When a voltage is applied between the second opposing electrode 18 and the third pixel electrode 15 so that the potential of the second opposing electrode 18 exceeds the potential of the third pixel electrode 15, holes which are positive charges are collected in the third pixel electrode 15, and electrons which are negative charges are collected in the second opposing electrode 18. The holes collected in the third pixel electrode 15 are accumulated in the third plug 33 and the third charge accumulation region 5.

[0070] A blocking layer that prevents electric charges from flowing into the pixel electrode in the dark may be provided between the pixel electrode and the photoelectric conversion layer.

[0071] The imaging element 100 of this embodiment has a multi-layer structure. "Multi-layer" means that a plurality of photoelectric conversion layers are present in the normal direction of the semiconductor substrate 1. The multi-layer structure is advantageous in increasing the sensitivity of the pixel because it is possible to secure a sufficient area for the pixel electrode. In this embodiment, since there are three photoelectric conversion layers, the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123, it can be said that the imaging element 100 has a three-layer structure. The first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123 typically have different photoelectric conversion characteristics from each other.

[0072] According to the imaging element 100 having a three-layer structure, the three photoelectric conversion layers may include a photoelectric conversion layer sensitive to blue light, a photoelectric conversion layer sensitive to green light, and a photoelectric conversion layer sensitive to red light. Therefore, the three-layer structure is suitable for forming a full-color image.

[0073] The arrangement of plugs for suppressing crosstalk between the plugs will be described below. In this specification, the plugs are represented by two, three or four different symbols.

[0074] The description of this embodiment can be applied not only to the imaging element 100 having a three-layer structure, but also to an imaging element having a two-layer structure. The third photoelectric conversion layer 123, the third pixel electrode 15, and the third plug 33 can be any elements. When the description of this embodiment is applied to an imaging element having a two-layer structure, the description of the third photoelectric conversion layer 123, the third pixel electrode 15, and the third plug 33 is excluded.

[0075] Fig. 3A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 when the imaging element 100 is viewed from the normal direction of the semiconductor substrate 1. In other words, Fig. 3A is a projection view of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 onto a plane perpendicular to the normal direction of the semiconductor substrate 1.

[0076] In this specification, viewing the imaging element 100 from the normal direction of the semiconductor substrate 1 is synonymous with viewing the imaging element 100 from a planar view.

[0077] The pixel electrodes in the lower layer are cut out as necessary to avoid the plugs in the upper layer. Specifically, the first pixel electrode 13 is rectangular. The second pixel electrode 14 has a cutout for passing the first plug 31. The third pixel electrode 15 has a cutout for passing the first plug 31 and a cutout for passing the second plug 32. With this configuration, the areas of the second pixel electrode 14 and the third pixel electrode 15 can be maximized while securing the space for the first plug 31 and the second plug 32 to pass through. This makes it possible to give each pixel electrode the same degree of sensitivity. In this embodiment, the area of ​​the first pixel electrode 13 is larger than the area of ​​the second pixel electrode 14. The area of ​​the second pixel electrode 14 is larger than the area of ​​the third pixel electrode 15. The first pixel electrode 13 located in the uppermost layer does not have a cutout. The first pixel electrode 13 has, for example, a square shape.

[0078] When the imaging element 100 is viewed from the normal direction of the semiconductor substrate 1, in multiple adjacent pixels 10, the distance Lc between the nearest plugs is equal to or greater than 1 / 2 of the pixel pitch L. There is no particular upper limit to the distance Lc. The distance Lc is smaller than the pixel pitch L. When a pixel 10 arbitrarily selected from the multiple pixels 10 is defined as a first pixel, and multiple pixels 10 adjacent to the first pixel are defined as multiple second pixels, the distance between the nearest plugs is equal to or greater than 1 / 2 of the pixel pitch in the first pixel and the multiple second pixels.

[0079] As shown in FIG. 3A, in a plurality of pixels 10 adjacent to each other, the closest plugs are the second plug 32 and the third plug 33. The distance between the second plug 32 and the third plug 33 is represented by the distance Lc. The "distance between plugs" means the distance between the centers of the plugs. The shape of the plug in a plan view is not necessarily circular. Therefore, the "center of the plug" means the center of gravity of the plug. The "pixel pitch" means the repeating period of the pixels 10. The pixel pitch L corresponds to the distance between the centers of two adjacent pixels 10. The repeating period of the pixels 10 corresponds to the distance between specific plugs. For example, the distance between any first plug 31 and the first plug 31 closest to that first plug 31 is equal to the pixel pitch L. The position of the second plug 32 and the position of the third plug 33 may be interchanged.

[0080] According to this embodiment, since the plugs are sufficiently separated from each other in the adjacent pixels 10, it is possible to suppress crosstalk between the plugs in the adjacent pixels 10. As a result, it is possible to suppress color mixing in the image to be obtained.

[0081] A wiring layer may be provided between the semiconductor substrate 1 and the third photoelectric conversion layer 123. When a wiring layer is provided, the first plug 31, the second plug 32, and the third plug 33 may be electrically connected to the first charge accumulation region 3, the second charge accumulation region 4, and the third charge accumulation region 5, respectively, via the wiring layer. When the first plug 31, the second plug 32, and the third plug 33 are connected to the first charge accumulation region 3, the second charge accumulation region 4, and the third charge accumulation region 5, respectively, via the wiring layer, the "distance between the plugs" means the distance between the portions connecting the pixel electrode and the wiring layer.

[0082] In the adjacent pixels 10, the distance La between the first plug 31 and the second plug 32 is 1 / 2 or more of the pixel pitch L, and is, for example, greater than the distance Lc. In the adjacent pixels 10, the distance Lb between the first plug 31 and the third plug 33 is 1 / 2 or more of the pixel pitch L, and is, for example, greater than the distance Lc. That is, in the adjacent pixels 10, the distance between the first plug 31 and the second plug 32 or the third plug 33 is sufficiently secured. The first plug 31 is longer than the second plug 32 and longer than the third plug 33. The first plug 31 is the longest plug and is susceptible to crosstalk. By securing a sufficient distance between the first plug 31 and the second plug 32 or the third plug 33, the effect of suppressing crosstalk can be maximized.

[0083] However, the positions of the first plug 31 and the second plug 32 may be interchanged. The positions of the first plug 31 and the third plug 33 may be interchanged. In other words, in adjacent pixels 10, the closest plugs may be the first plug 31 and the third plug 33, or the first plug 31 and the second plug 32.

[0084] The distance La between the first plug 31 and the second plug 32 in the adjacent pixels 10 may be longer than or equal to the distance Lb between the first plug 31 and the third plug 33 in the adjacent pixels 10.

[0085] In the image sensor 100 of this embodiment, there are eight pixels 10 adjacent to a particular pixel 10, except when the pixel 10 located at the outermost periphery of the image sensor 100 is the particular pixel 10. This also applies to the other embodiments.

[0086] 3B shows an arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 in a specific pixel 10 of the imaging element 100. In this embodiment, the distance Lα between the first plug 31 and the second plug 32 in the pixel 10 is equal to or greater than ½ of the pixel pitch L. With this configuration, crosstalk between the plugs in the pixel 10 can be further suppressed. As a result, color mixing in the image to be obtained can be suppressed.

[0087] Furthermore, in this embodiment, the distance Lβ between the first plug 31 and the third plug 33 in the pixel 10 is equal to or greater than ½ of the pixel pitch L. This configuration can further suppress crosstalk between the plugs in the pixel 10. As a result, color mixing in the image to be obtained can be suppressed.

[0088] Furthermore, in this embodiment, the distance Lγ between the second plug 32 and the third plug 33 in the pixel 10 is equal to or greater than ½ of the pixel pitch L. This configuration can further suppress crosstalk between the plugs in the pixel 10. As a result, color mixing in the image to be obtained can be suppressed.

[0089] The first plug 31 is the longest plug, and the second plug 32 is longer than the third plug 33. Therefore, the influence of crosstalk between the first plug 31 and the second plug 32 is large. If the plugs are arranged so that the relationships Lα>Lβ and Lα>Lγ are satisfied, the crosstalk can be suppressed more effectively.

[0090] A shield electrode maintained at a constant potential may be provided between adjacent pixels 10. The shield electrode can further suppress crosstalk between the plugs in the adjacent pixels 10.

[0091] In the normal direction of the semiconductor substrate 1, the first charge accumulation region 3 can be disposed at a position overlapping with the first plug 31. Similarly, the second charge accumulation region 4 can be disposed at a position overlapping with the second plug 32. The third charge accumulation region 5 can be disposed at a position overlapping with the third plug 33. With this configuration, crosstalk due to coupling between the charge accumulation regions can also be suppressed.

[0092] (Variation 1) FIG. 4A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, and the first plug 31, the second plug 32, and the third plug 33 according to the first modification. FIG. 4B shows the arrangement of the pixel electrodes and plugs in a specific pixel of the first modification. According to this modification, in a plurality of adjacent pixels 10, the distance Lc between the nearest plugs is equal to or greater than 1 / 2 of the pixel pitch L. In a plurality of adjacent pixels 10, the nearest plugs are the second plug 32 and the third plug 33. The distance between the second plug 32 and the third plug 33 is represented by the distance Lc. In a plurality of adjacent pixels 10, the distance La between the first plug 31 and the second plug 32 is equal to the distance Lc. That is, in a plurality of adjacent pixels 10, the distance La is also the distance between the nearest plugs. In a plurality of adjacent pixels 10, the distance Lb between the first plug 31 and the third plug 33 is also equal to or greater than 1 / 2 of the pixel pitch L.

[0093] 4B, in this modification, the first pixel electrode 13 and the second pixel electrode 14 are arranged with a shift of ½ or more of the length W of one side of the second pixel electrode 14. In other words, the distance F between the first plug 31 and the second plug 32 is W / 2 or more. The position of the center of gravity of the first pixel electrode 13 and the position of the center of gravity of the second pixel electrode 14 are shifted from each other. With this configuration, crosstalk between plugs or crosstalk between charge accumulation regions can be suppressed without providing a notch or a through-hole in the second photoelectric conversion layer 122.

[0094] In detail, the first pixel electrode 13 has a square shape in a plan view. The first plug 31 is disposed in the central region of the first pixel electrode 13. The second pixel electrode 14 has a square shape in a plan view. The second plug 32 is disposed in the central region of the second pixel electrode 13. The positional relationship between the first pixel electrode 13 and the second pixel electrode 14 is determined so that the first plug 31 passes outside the range of the second pixel electrode 14. With this configuration, it is not necessary to provide a through hole for passing the first plug 31 in the second pixel electrode 14. The "central region of the pixel electrode" means a region having a certain width including the center of gravity of the pixel electrode when the pixel electrode is viewed in a plan view. Specifically, when the pixel electrode has a roughly rectangular shape in a plan view, the pixel electrode is divided into nine rectangular regions so that the areas of the divided regions are equal to each other. The region including the center of gravity of the pixel electrode among the nine rectangular regions is the central region. When a notch or the like is provided in the pixel electrode, the smallest rectangle surrounding the pixel electrode can be divided into nine. The center of gravity of a pixel electrode may be the center of gravity of the smallest rectangle that encloses the pixel electrode.

[0095] The first plug 31 may be disposed at the center of the first pixel electrode 13. In other words, when the imaging element 100 is viewed in a plan view, the center of the first pixel electrode 13 may overlap with the first plug 31. The "center of the pixel electrode" may be the center of gravity of the pixel electrode when the pixel electrode is viewed in a plan view.

[0096] In this specification, the term "planar view" is synonymous with viewing the image sensor 100 from the normal direction of the semiconductor substrate 1.

[0097] Like the first pixel electrode 13 and the second pixel electrode 14, the third pixel electrode 15 has a square shape in a plan view. The third plug 33 is disposed in the central region of the third pixel electrode 15. The positional relationship between the first pixel electrode 13, the second pixel electrode 14, and the third pixel electrode 15 is determined so that the first plug 31 and the second plug 32 pass outside the range of the third pixel electrode 15. With this configuration, it is not necessary to provide a through hole in the third pixel electrode 33 for passing the first plug 31 and the second plug 32. The first plug 31, the second plug 32, and the third plug 33 are disposed at the vertices of an equilateral triangle. The distance between the first plug 31 and the third plug 33 is also equal to the distance F. The distance between the second plug 32 and the third plug 33 is also equal to the distance F.

[0098] The third plug 33 may be disposed at the center of the third pixel electrode 15. In other words, when the image sensor 100 is viewed in a plan view, the center of the third pixel electrode 15 may overlap the third plug 33.

[0099] The first pixel electrode 13 and the third pixel electrode 14 are arranged with a shift of ½ or more of the length W of one side of the second pixel electrode 14. The second pixel electrode 14 and the third pixel electrode 15 are arranged with a shift of ½ or more of the length W of one side of the second pixel electrode 14. The position of the center of gravity of the first pixel electrode 13, the position of the center of gravity of the second pixel electrode 14, and the position of the center of gravity of the third pixel electrode 15 are shifted from each other.

[0100] Fig. 4C shows another arrangement of pixel electrodes and plugs in a specific pixel of Modification 1. In the example shown in Fig. 4C as well, the first pixel electrode 13 and the second pixel electrode 14 are arranged with a shift of 1 / 2 or more of the length W of one side of the second pixel electrode 14. In other words, the distance F between the first plug 31 and the second plug 32 is W / 2 or more.

[0101] In the normal direction of the semiconductor substrate 1, the upper pixel electrode of a particular pixel 10 overlaps the lower pixel electrode of an adjacent pixel 10. According to the example shown in Fig. 4C, it is possible to increase the area of ​​each pixel electrode.

[0102] (Variation 2) FIG. 5A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 according to the second modification. FIG. 5B shows the arrangement of the pixel electrodes and plugs in a specific pixel of the second modification. According to this modification, in a plurality of adjacent pixels 10, the distance between the nearest plugs is equal to or greater than 1 / 2 of the pixel pitch L. According to this modification, the distance between the plugs in a plurality of adjacent pixels 10 is equal to L / 2. In a plurality of adjacent pixels 10, the nearest plugs are the first plug 31 and the third plug 33, or the second plug 32 and the third plug 33. In a plurality of adjacent pixels 10, the distance Lb between the first plug 31 and the third plug 33 is equal to L / 2. In a plurality of adjacent pixels, the distance Lc between the second plug 32 and the third plug 33 is equal to L / 2. The distance La between the first plug 31 and the second plug 32 is equal to L(1 / 2) 1 / 2 is equal to.

[0103] 5B, in this modification, the first pixel electrode 13 and the second pixel electrode 14 are also arranged with a shift of ½ or more of the length W of one side of the second pixel electrode 14. In other words, the distance F between the first plug 31 and the second plug 32 is W / 2 or more. The distance F is W(½) 1 / 2 The distance between the second plug 32 and the third plug 33 is equal to W / 2.

[0104] Two third plugs 33 are connected to the third pixel electrode 15. The third pixel electrode 15 has a rough shape of a rectangle having long and short sides. The direction of the long side is perpendicular to the straight line connecting the first plug 31 and the second plug 32. When the imaging element 100 is viewed in a plan view, the first plug 31, the second plug 32, and the third plug 33 are located on lattice points of a square lattice. The first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, and the first plug 31, the second plug 32, and the third plug 33 are arranged so that the plugs in the upper layer avoid the pixel electrodes in the lower layer. The first plug 31 passes outside the range of the second pixel electrode 14 and the third pixel electrode 15. The second plug 32 passes outside the range of the third pixel electrode 15.

[0105] The second pixel electrode 14 and the third pixel electrode 15 have cutouts to avoid the plugs in the upper layers. The first pixel electrode 15 is the uppermost pixel electrode, so it may or may not have a cutout.

[0106] (Variation 3) FIG. 6A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 according to the modified example 3. FIG. 6B shows the arrangement of the pixel electrodes and plugs in a specific pixel of the modified example 3. Except for the adoption of a square third pixel electrode 15 instead of the rectangular third pixel electrode 15, the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 in this modified example is the same as that in the modified example 2. The third pixel electrode 15 is provided with a cutout to avoid the first plug 31 and the second plug 32. In this modified example, the distance between the nearest plugs in the plurality of adjacent pixels 10 is 1 / 2 or more of the pixel pitch L. In the plurality of adjacent pixels 10, the nearest plugs are the first plug 31 and the third plug 33, or the second plug 32 and the third plug 33.

[0107] (Variation 4) FIG. 7A shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 according to the fourth modification. FIG. 7B shows the arrangement of the pixel electrodes and plugs in a specific pixel of the second modification. Except for the adoption of the square third pixel electrode 15 without a notch, the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the first plug 31, the second plug 32, and the third plug 33 in this modification is the same as that in the third modification. The area of ​​the first pixel electrode 13 is larger than that of the second pixel electrode 14 and is larger than that of the third pixel electrode 15. In this modification, the distance between the nearest plugs in the plurality of adjacent pixels 10 is 1 / 2 or more of the pixel pitch L. In the plurality of adjacent pixels 10, the nearest plugs are the first plug 31 and the third plug 33, or the second plug 32 and the third plug 33.

[0108] Second embodiment 8A shows the configuration of an image sensor 200 according to the second embodiment of the present disclosure. The image sensor 200 has a four-layer structure. The image sensor 200 has a fourth photoelectric conversion layer 124, a fourth pixel electrode 16, and a fourth plug 34 in addition to the configuration of the image sensor 100 of the first embodiment.

[0109] In the normal direction of the semiconductor substrate 1, the fourth photoelectric conversion layer 124 is disposed, for example, between the third photoelectric conversion layer 123 and the semiconductor substrate 1. The fourth pixel electrode 16 is electrically connected to the fourth photoelectric conversion layer 124 and collects charges corresponding to light in a fourth wavelength range. The fourth wavelength range is, for example, a wavelength range of near-infrared light. The fourth photoelectric conversion layer 124 is made of a material sensitive to near-infrared light. The fourth plug 34 electrically connects the semiconductor substrate 1 and the fourth pixel electrode 16.

[0110] Visible light is absorbed by the upper layers, the first photoelectric conversion layer 121, the second photoelectric conversion layer 122, and the third photoelectric conversion layer 123. Since visible light does not reach the fourth photoelectric conversion layer 124 that is sensitive to near-infrared light, an image based on near-infrared light can be obtained by the fourth photoelectric conversion layer 124.

[0111] Fig. 8B shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 when the imaging element 200 is viewed from the normal direction of the semiconductor substrate 1. Fig. 8C shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 in a specific pixel 10.

[0112] When the fourth pixel electrode 16 and the fourth plug 34 are added to the arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, and the first plug 31, the second plug 32, and the third plug 33 in variant example 3, the arrangement becomes the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 in the imaging element 200 of this embodiment.

[0113] In this embodiment, the distance between the closest plugs in the adjacent pixels 10 is equal to or greater than 1 / 2 of the pixel pitch L. According to this embodiment, the distance between the plugs in the adjacent pixels 10 is equal to L / 2. In the adjacent pixels 10, the closest plugs are the first plug 31 and the third plug 33, the second plug 32 and the third plug 33, or the first plug 31 and the fourth plug 34. In the adjacent pixels 10, the distance Lb between the first plug 31 and the third plug 33 is equal to L / 2. In the adjacent pixels 10, the distance Lc between the second plug 32 and the third plug 33 is equal to L / 2. In the adjacent pixels 10, the distance Ld between the first plug 31 and the fourth plug 34 is equal to L / 2. The distance La between the first plug 31 and the second plug 32 is equal to L(1 / 2) 1 / 2 is equal to.

[0114] When the imaging element 200 is viewed in plan, the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 are located on the lattice points of a square lattice. The first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 are arranged so that the plugs in the upper layer avoid the pixel electrodes in the lower layer. The first plug 31 passes outside the ranges of the second pixel electrode 14, the third pixel electrode 15, and the fourth pixel electrode 16. The second plug 32 passes outside the ranges of the third pixel electrode 15 and the fourth pixel electrode 16. The third plug 33 passes outside the range of the fourth pixel electrode 16.

[0115] (Variation 5) Fig. 9A shows an arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 according to Modification 5. Fig. 9B shows an arrangement of the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 in a specific pixel 10 of Modification 5.

[0116] In this modification, the distance between the closest plugs in the adjacent pixels 10 is equal to or greater than 1 / 2 of the pixel pitch L. According to this modification, the distance between the plugs in the adjacent pixels 10 is equal to L / 2. In the adjacent pixels 10, the closest plugs are the first plugs 31, the second plugs 32, the third plugs 33, or the fourth plugs 34. In the adjacent pixels 10, the distance L1 between the first plugs 31 is equal to the distance L2 between the second plugs 32, the distance L3 between the third plugs 33, and the distance L4 between the fourth plugs 34. In other words, the inverted arrangement of the pixels 10 is determined so that such a relationship is established in the adjacent pixels 10.

[0117] According to the configuration of this modification, the closest plugs are of the same color in a plurality of adjacent pixels 10. Therefore, not only is crosstalk between the plugs suppressed, but the effect of suppressing color mixing is additionally obtained.

[0118] In this modification, the first pixel electrode 13, the second pixel electrode 14, the third pixel electrode 15, the fourth pixel electrode 16, and the first plug 31, the second plug 32, the third plug 33, and the fourth plug 34 are arranged so that the plugs in the upper layer avoid the pixel electrodes in the lower layer. The first plug 31 passes outside the range of the second pixel electrode 14, the third pixel electrode 15, and the fourth pixel electrode 16. In other words, the second pixel electrode 14, the third pixel electrode 15, and the fourth pixel electrode 16 have a notch for passing the first plug 31. The second plug 32 passes outside the range of the third pixel electrode 15 and the fourth pixel electrode 16. In other words, the third pixel electrode 15 and the fourth pixel electrode 16 have a notch for passing the second plug 32. The third plug 33 passes outside the range of the fourth pixel electrode 16. In other words, the fourth pixel electrode 16 has a notch for passing the third plug 33.

[0119] Third embodiment 10A shows a configuration of an image sensor 300 according to a third embodiment of the present disclosure. The image sensor 300 has a two-layer structure. The image sensor 300 has a configuration in which, for example, one set of photoelectric conversion layer, pixel electrodes, and plugs are omitted from the image sensor 100 of the first embodiment.

[0120] The first photoelectric conversion layer 121 collects charges corresponding to light in a first wavelength range. The second photoelectric conversion layer 122 collects charges corresponding to light in a second wavelength range. The first wavelength range is, for example, the wavelength range of visible light. The first photoelectric conversion layer 121 can be made of a photoelectric conversion material sensitive to visible light. By using a color filter, it is possible to obtain blue, green, and red information from the first photoelectric conversion layer 121 to form a full-color image. It is also possible to obtain a monochrome image from the first photoelectric conversion layer 121. The second wavelength range is, for example, the wavelength range of near-infrared light. The second photoelectric conversion layer 122 can be made of a photoelectric conversion material sensitive to visible light. It is possible to form an image based on near-infrared light information from the second photoelectric conversion layer 122.

[0121] Fig. 10B shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 when the imaging element 300 is viewed from the normal direction of the semiconductor substrate 1. Fig. 10C shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, and the second plug 32 in a specific pixel 10.

[0122] In this embodiment as well, in a plurality of adjacent pixels 10, the distance between the closest plugs is ½ or more of the pixel pitch L. In a plurality of adjacent pixels 10, the closest plugs are the first plugs 31 and the second plugs 32. In this embodiment, the distance between all of the first plugs 31 and the second plugs 32 is the distance Lt. That is, the first plugs 31 and the second plugs 32 are arranged on the lattice points of a square lattice with one side having the length Lt. The distance Lt is ½ or more of the pixel pitch L and is smaller than the pixel pitch L.

[0123] In this embodiment as well, since the plugs are sufficiently spaced apart from one another, it is possible to suppress crosstalk between the plugs in a plurality of adjacent pixels 10. As a result, it is possible to suppress color mixing in the image to be obtained.

[0124] The first plug 31 and the second plug 32 may be arranged diagonally. The first plug 31 and the second plug 32 may be arranged near the diagonal of the first pixel electrode 13. The first plug 31 and the second plug 32 may be arranged on the diagonal of the first pixel electrode 13. With such an arrangement, crosstalk can be more effectively suppressed. "The plugs are arranged on the diagonal of the first pixel electrode 13" means that each plug overlaps with the diagonal of the smallest rectangle surrounding the first pixel electrode 13 when the image sensor is viewed in a plan view.

[0125] (Fourth embodiment) 11A shows a cross section of an image sensor 400 according to the fourth embodiment. The image sensor 400 also has a two-layer structure. Each pixel of the image sensor 400 further includes a photodiode PD instead of the third photoelectric conversion layer 123, the third pixel electrode 15, the third plug 33, and the third charge accumulation region 5 of the image sensor 100 described with reference to FIG. 2.

[0126] The photodiode PD is provided on the semiconductor substrate 1. Each of the first pixel electrode 13 and the second pixel electrode 14 has light-transmitting properties. Between the photodiode PD and the second photoelectric conversion layer 122, a color filter 19r or a color filter 19b is provided. Each of the photodiodes PD is covered with the color filter 19r or the color filter 19b. Between the photodiode PD and the color filters 19r and 19b, an insulating layer 25 is provided. The insulating layer 25 is made of an insulating material such as SiO2. Between the second pixel electrode 14 and the color filters 19r and 19b, an insulating layer 9 is present. The insulating layer 9 also functions as a planarization layer and can be made of a transparent resin such as an acrylic resin or an epoxy resin. The imaging element 400 includes a condenser lens 21. The condenser lens 21 functions to effectively guide light to the photodiode PD. The condenser lens is synonymous with the microlens described above.

[0127] The first photoelectric conversion layer 121 has sensitivity to, for example, a wavelength range of near-infrared light. The first photoelectric conversion layer 121 can be made of a photoelectric conversion material having sensitivity to the wavelength range of near-infrared light. The second photoelectric conversion layer 122 has sensitivity to, for example, a wavelength range of green light. The second photoelectric conversion layer 122 can be made of a photoelectric conversion material having sensitivity to the wavelength range of green light. The photodiode PD is typically a silicon photodiode. The color filter 19r is a filter that cuts off red light. The color filter 19b is a filter that cuts off blue light.

[0128] Since the first photoelectric conversion layer 121 has sensitivity to the wavelength region of near-infrared light, and the second photoelectric conversion layer 122 has sensitivity to the wavelength region of green light, the red light and the blue light reach the color filters 19r and 19b. The red light is blocked by the color filter 19r, and only the blue light is incident on the photodiode PD. The blue light is blocked by the color filter 19b, and only the red light is incident on the photodiode PD. Therefore, the imaging element 400 can form an image based on near-infrared light and a full-color image.

[0129] 11B shows the arrangement of the first pixel electrode 13, the second pixel electrode 14, the first plug 31, the second plug 32, and the photodiode PD when the image sensor 400 is viewed from the normal direction of the semiconductor substrate 1. As the arrangement of the first plug 31 and the second plug 32 in the image sensor 400 of this embodiment, for example, the arrangement of the first plug 31 and the second plug 32 described with reference to FIGS. 10A to 10C is adopted.

[0130] That is, in a plurality of adjacent pixels 10, the distance between the closest plugs is ½ or more of the pixel pitch L. In a plurality of adjacent pixels 10, the closest plugs are the first plug 31 and the second plug 32. In this embodiment, the distance between all the plugs 31 and 32 is the distance Lt. That is, the first plugs 31 and the second plugs 32 are arranged on the lattice points of a square lattice with one side having the length Lt. The distance Lt is ½ or more of the pixel pitch L and is smaller than the pixel pitch L.

[0131] In this embodiment as well, since the plugs are sufficiently spaced apart from one another, it is possible to suppress crosstalk between the plugs in a plurality of adjacent pixels 10. As a result, it is possible to suppress color mixing in the image to be obtained.

[0132] Fifth embodiment 12 shows an arrangement of a first pixel electrode 13, a second pixel electrode 14, a third pixel electrode 15, a first plug 31, a second plug 32, and a third plug 33 in a specific pixel of an image sensor according to a fifth embodiment of the present disclosure. The image sensor according to this embodiment has a three-layer structure similar to that of the image sensor 100 according to the first embodiment.

[0133] The first pixel electrode 13 has, for example, a square shape in a plan view. Since the first photoelectric conversion layer 121 is the uppermost photoelectric conversion layer, the first pixel electrode 13 does not need to have a notch for passing a plug. The second pixel electrode 14 and the third pixel electrode 15 have a notch for passing the first plug 31. The third pixel electrode 15 has a notch for passing the second plug 32.

[0134] In this embodiment, when viewed from the normal direction of the semiconductor substrate 1, the distance between the first plug 31 and the second plug 32 is longer than the long side P of the first pixel electrode 13. With this configuration, crosstalk due to coupling between the first plug 31 and the second plug 32 is suppressed in each pixel 10. As a result, noise can be reduced.

[0135] In this embodiment, the first plug 31 and the second plug 32 are arranged diagonally. The first plug 31 and the second plug 32 may be arranged near the diagonal of the first pixel electrode 13. The first plug 31 and the second plug 32 may be arranged on the diagonal of the first pixel electrode 13. With such an arrangement, crosstalk can be more effectively suppressed.

[0136] The third photoelectric conversion layer 123 is the photoelectric conversion layer located at the bottom. The third plug 33 is shorter than the first plug 31 and shorter than the second plug 32. The influence of crosstalk between the third plug 33 and other plugs is small. Therefore, the third plug 33 can be disposed at any position. In this embodiment, the third plug 33 is disposed in the central region of the third pixel electrode 15. According to such a configuration, the distance between the first charge accumulation region 3, the second charge accumulation region 4, and the third charge accumulation region 5 can be sufficiently secured. This makes it possible to suppress crosstalk between the charge accumulation regions, and also to suppress crosstalk between the charge accumulation regions and the plugs. The design freedom of the third charge accumulation region 5 and the transistor connected to the third plug 33 is also improved.

[0137] The third plug 33 may be disposed on the midpoint of a line segment connecting the first plug 31 and the second plug 32. The line segment connecting the first plug 31 and the second plug 32 means a line segment connecting the center of gravity of the first plug 31 and the center of gravity of the second plug 32 when the imaging element is viewed in a plan view. "The third plug 33 is disposed on the midpoint of the line segment" means that the third plug 33 overlaps with the midpoint.

[0138] In this embodiment, the shape of the pixel electrodes is not particularly limited, and may be a rectangle having long and short sides, or a polygon such as a regular hexagon or a regular octagon.

[0139] Fig. 13A shows a pixel electrode having a regular hexagonal shape. Fig. 13B shows a pixel electrode having a regular octagonal shape. In the case of a regular hexagon, the diagonal DL that does not pass through the center of the regular hexagon is defined as the long side. In the case of a regular octagon, the diagonal DL that does not pass through the center of the regular octagon is also defined as the long side. In the examples shown in Figs. 13A and 13B, the distance between the first plug 31 and the second plug 32 is longer than the diagonal DL, which is the long side of the first pixel electrode 13.

[0140] A notch CP1 is provided in the second pixel electrode 14 and the third pixel electrode 15, which are pixel electrodes in the lower layer, in order to extend the first plug 31 downward and connect it to the semiconductor substrate 1. A notch CP2 is further provided in the third pixel electrode 15, which is a pixel electrode in the lower layer, in order to extend the second plug 32 downward and connect it to the semiconductor substrate 1.

[0141] Sixth embodiment FIG. 14 shows a cross section of an imaging element 500 according to a sixth embodiment of the present disclosure. The imaging element 500 differs from the imaging elements of the previous embodiments in the structure of the electrodes. In the imaging element 500, the first pixel electrode 13 has a first storage electrode 13a, a first readout electrode 13b, and a first transfer electrode 13c. The second pixel electrode 14 has a second storage electrode 14a, a second readout electrode 14b, and a second transfer electrode 14c. The third pixel electrode 15 has a third storage electrode 15a, a third readout electrode 15b, and a third transfer electrode 15c. The first transfer electrode 13c, the second transfer electrode 14c, and the third transfer electrode 15c may be omitted.

[0142] A first semiconductor layer 27 is provided between the first pixel electrode 13 and the first photoelectric conversion layer 121. A part of the insulating layer 8 is present between the first semiconductor layer 27 and the first pixel electrode 13. A second semiconductor layer 28 is provided between the second pixel electrode 14 and the second photoelectric conversion layer 122. A part of the insulating layer 8 is present between the second semiconductor layer 28 and the second pixel electrode 14. A third semiconductor layer 29 is provided between the third pixel electrode 15 and the third photoelectric conversion layer 123. A part of the insulating layer 9 is present between the third semiconductor layer 29 and the third pixel electrode 15. The first semiconductor layer 27, the second semiconductor layer 28, and the third semiconductor layer 29 are provided to more efficiently accumulate charges, and are made of a semiconductor material having light transmission properties.

[0143] The first storage electrode 13a and the first transfer electrode 13c face the first photoelectric conversion layer 121 through a part of the insulating layer 8, or through a part of the insulating layer 8 and the first semiconductor layer 27. At least a part of the first readout electrode 13b is in contact with the first photoelectric conversion layer 121 directly or through the first semiconductor layer 27. The first readout electrode 13b is connected to a first plug 31. The first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c are each electrically connected to a wiring not shown. A desired voltage can be applied to each of the first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c. The first storage electrode 13a can function as a charge storage electrode for attracting charges generated in the first photoelectric conversion film 121 according to the applied voltage and storing the charges in the first photoelectric conversion layer 121. When the imaging element 500 is viewed in plan, the first transfer electrode 13c is disposed between the first storage electrode 13a and the first readout electrode 13b. The first transfer electrode 13c plays a role of blocking the accumulated electric charge and controlling the transfer of the electric charge. By controlling the voltages applied to the first storage electrode 13a, the first readout electrode 13b, and the first transfer electrode 13c, the electric charge generated in the first photoelectric conversion layer 121 can be accumulated inside the first photoelectric conversion layer 121 or at the interface of the first photoelectric conversion layer 121, or the generated electric charge can be taken out to the first charge accumulation region 3. These explanations regarding the first pixel electrode 13 can also be applied to the second pixel electrode 14 and the third pixel electrode 15 by replacing "first" with "second" or "third."

[0144] According to the electrode structure of this embodiment, the charges generated in the photoelectric conversion layer can be efficiently collected and transferred, leading to improved sensitivity. The electrode structure of this embodiment can be applied to all of the embodiments described above. [Industrial Applicability]

[0145] The technology disclosed in this specification is useful for an imaging element. The imaging element can be applied to an imaging device, an optical sensor, etc. Examples of the imaging device include a digital camera, a medical camera, and a surveillance camera. [Explanation of symbols]

[0146] 1. Semiconductor substrate 3 First charge storage region 4 Second charge storage region 5 Third charge storage region 10 pixels 12 Photoelectric conversion section 13 First pixel electrode 14 Second pixel electrode 15 Third pixel electrode 16 4th pixel electrode 17 First opposing electrode 18 Second counter electrode 19r,19b color filters 31 First plug 32 2nd plug 33 3rd plug 34 4th plug 100,200,300,400,500 Image sensor 100A Imaging Device 121 First photoelectric conversion layer 122 Second photoelectric conversion layer 123 Third photoelectric conversion layer 124 4th photoelectric conversion layer PD Photodiode

Claims

1. A semiconductor substrate; A plurality of pixels; Equipped with Each of the plurality of pixels is a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate and configured to convert light into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Including, the plurality of pixels includes a first pixel and a plurality of second pixels adjacent to the first pixel, When viewed from a normal direction of the semiconductor substrate, in the first pixel and the plurality of second pixels, a distance between the nearest plugs of the first plug and the nearest plugs of the second plug is equal to or greater than ½ of a pixel pitch, which is the shortest distance between a center of the first pixel and a center of each of the plurality of second pixels. Image sensor.

2. When viewed from the normal direction of the semiconductor substrate, a distance between the first plug and the second plug in each of the plurality of pixels is equal to or greater than half of the pixel pitch. The imaging device according to claim 1 .

3. Each of the plurality of pixels is a third photoelectric conversion layer disposed between the second photoelectric conversion layer and the semiconductor substrate and configured to convert light into a third charge; a third pixel electrode for collecting the third charges; a third plug electrically connecting the semiconductor substrate and the third pixel electrode; Further comprising: The imaging device according to claim 1 .

4. When viewed from the normal direction of the semiconductor substrate, a distance between the first plug and the third plug in each of the plurality of pixels is equal to or greater than half of the pixel pitch. The imaging device according to claim 3 .

5. When viewed from the normal direction of the semiconductor substrate, a distance between the second plug and the third plug in each of the plurality of pixels is equal to or greater than half of the pixel pitch. The imaging device according to claim 3 .

6. When viewed from a normal direction of the semiconductor substrate, in each of the plurality of pixels, a distance between the first plug and the second plug is longer than a distance between the first plug and the third plug and is also longer than a distance between the second plug and the third plug; The imaging device according to claim 3 .

7. a shield electrode maintained at a constant potential between the first pixel and each of the plurality of second pixels; The imaging device according to claim 1 .

8. A semiconductor substrate; a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate and configured to convert light into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Equipped with the first pixel electrode has a long side and a short side; When viewed from a normal direction of the semiconductor substrate, a distance between the first plug and the second plug is longer than the long side of the first pixel electrode. Image sensor.

9. a third photoelectric conversion layer disposed between the second photoelectric conversion layer and the semiconductor substrate and configured to convert light into a third charge; a third pixel electrode for collecting the third charges; a third plug electrically connecting the semiconductor substrate and the third pixel electrode; Further comprising: The imaging device according to claim 8 .

10. the third plug is disposed in a central region that is a region including the center of gravity of the third pixel electrode; The imaging device according to claim 9 .

11. A semiconductor substrate; a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode for collecting the first charges; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate and configured to convert light into a second charge; a second pixel electrode for collecting the second charges; a third photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate and configured to convert light into a third charge; a third pixel electrode for collecting the third charges; Equipped with the first pixel electrode has a plurality of sides; the second pixel electrode has a plurality of sides; the third pixel electrode has a plurality of sides; When viewed from a normal direction of the semiconductor substrate, the first pixel electrode and the second pixel electrode are arranged to be shifted by ½ or more of the length of each of the multiple sides of the second pixel electrode, the second pixel electrode and the third pixel electrode are arranged to be shifted by ½ or more of the length of each of the multiple sides of the third pixel electrode, and the third pixel electrode and the first pixel electrode are arranged to be shifted by ½ or more of the length of each of the multiple sides of the first pixel electrode. Image sensor.

12. a first plug electrically connecting the semiconductor substrate and the first pixel electrode; the first plug is disposed in a central region that is a region including the center of gravity of the first pixel electrode; The imaging device according to claim 11.

13. a second plug electrically connecting the semiconductor substrate and the second pixel electrode; The imaging device according to claim 11 or 12.

14. The second plug does not penetrate the third pixel electrode. The imaging device according to claim 13.

15. A semiconductor substrate, a first photoelectric conversion layer that converts light into a first charge; a first pixel electrode for collecting the first charges; a first plug electrically connecting the semiconductor substrate and the first pixel electrode; a second photoelectric conversion layer disposed between the first photoelectric conversion layer and the semiconductor substrate and configured to convert light into a second charge; a second pixel electrode for collecting the second charges; a second plug electrically connecting the semiconductor substrate and the second pixel electrode; Equipped with the second pixel electrode has a plurality of sides; When viewed from a normal direction of the semiconductor substrate, the first pixel electrode and the second pixel electrode are arranged to be shifted from each other by ½ or more of the length of each of the plurality of sides of the second pixel electrode, the shortest distance between the first plug and the second plug is equal to or greater than half of a pixel pitch, which is the shortest distance between a center of the first pixel and the center of each of the plurality of second pixels; Image sensor.

16. The first plug is disposed in a central region that is a region including a center of gravity of the first pixel electrode. The imaging device according to claim 15.

17. the first plug and the second plug are disposed at diagonal positions on the first pixel electrode; 17. The imaging device according to claim 1, wherein the first and second electrodes are arranged in a first direction.

18. the first pixel electrode includes a first storage electrode configured to store the first charge in the first photoelectric conversion layer, and a first readout electrode electrically connected to the semiconductor substrate via the first plug; the second pixel electrode includes a second storage electrode configured to store the second charge in the second photoelectric conversion layer, and a second readout electrode electrically connected to the semiconductor substrate via the second plug; The imaging device according to claim 1 .

19. The plurality of pixels are arranged in a plurality of rows and a plurality of columns, each of which is m rows and n columns; m and n each independently represent an integer of 1 or more; The imaging device according to claim 1 .

Images