Photoelectric conversion device

Abstract

To provide a photoelectric conversion device in which deterioration of a characteristic is suppressed.SOLUTION: A photoelectric conversion device comprises: a substrate; a light detection film 51 that includes a lower surface 51a; a plurality of pixel electrodes 50; a control electrode 60 that includes a first part 60a overlapped to the lower surface 51a and a second part 60b that is not overlapped with the lower surface 51a; a transference electrode 52; a connection part 61 that conducts the control electrode 60 and the transference electrode 52; and a power supply penetration wiring 62 that is connected to the first part 60a of the control electrode 60, and is extended to the substrate. The connection part 61 is contacted to a side surface of the light detection film 51 and the second part 60b of the control electrode 60. A plan view form of the light detection film 51 includes a concave part 51r. The second part 60b of the control electrode 60 is overlapped with a concave part 51r. The connection part 61 is connected to the second part 60b of the control electrode 60 in the concave part 51r. Each pixel electrode 50 and the control electrode 60 are contacted to the lower surface 51a of the light detection film 51.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a photoelectric conversion device. [Background technology]

[0002] An image sensor includes a photodetector element that generates an electric signal according to the amount of incident light, and has a number of pixels arranged one-dimensionally or two-dimensionally. A stacked image sensor is an image sensor that has photodetector elements as pixels, each of which has a structure in which a photoelectric conversion film is stacked on a substrate. Examples of such image sensors are disclosed in Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4729275 [Patent Document 2] JP 2019-016667 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a stacked image sensor, a transparent electrode may be formed on a photoelectric conversion film, and a through wiring for supplying power to the transparent electrode may be disposed.

[0005] The present disclosure provides a photovoltaic device in which the through wiring is protected from substances that cause deterioration of characteristics, such as moisture or oxygen, and deterioration of characteristics is suppressed. [Means for solving the problem]

[0006] A photoelectric conversion device according to one aspect of the present disclosure includes a substrate, a photodetection film having a first surface facing the substrate and a second surface opposite to the first surface, a plurality of first electrodes provided between the substrate and the photodetection film, a second electrode provided between the substrate and the photodetection film and having a first portion overlapping the first surface and a second portion not overlapping the first surface when viewed from a normal direction of the substrate, a third electrode provided on the second surface of the photodetection film, wiring connecting the second electrode and the third electrode, and a first conductive plug connected to the first portion of the second electrode and extending toward the substrate, the wiring contacts a side surface of the light detection film and the second portion of the second electrode, the planar shape of the light detection film as viewed from the normal direction of the substrate has a recess, the second portion of the second electrode overlaps the recess as viewed from the normal direction of the substrate, the wiring is connected to the second portion of the second electrode in the recess, and the first electrode and the second electrode are in contact with the first surface of the light detection film.

[0007] a second electrode provided between the substrate and the photodetection film and having a first portion overlapping the first portion and a second portion not overlapping the first portion when viewed from a normal direction of the substrate; a third electrode provided on the second portion of the photodetection film; wiring connecting the second electrode and the third electrode; and a first conductive plug connected to the first portion of the second electrode and extending toward the substrate, wherein the first conductive plug does not overlap the second portion of the second electrode when viewed from the normal direction of the substrate, and the wiring continuously covers a side surface of the photodetection film and the second portion of the second electrode. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a photoelectric conversion device in which deterioration of characteristics is suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a circuit configuration of an imaging device according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view that typically illustrates a cross section of a device structure of a pixel of the imaging device according to the first embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view of the image sensor according to the first embodiment. [Figure 4] FIG. 4 is a schematic top view of the image sensor according to the first embodiment with a protective film removed. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of the light detection film of the image sensor according to the first embodiment. [Figure 6A] FIG. 6A is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6B] FIG. 6B is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6C] FIG. 6C is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6D] FIG. 6D is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6E] FIG. 6E is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6F] FIG. 6F is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6G] FIG. 6G is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 6H] FIG. 6H is a schematic cross-sectional view for illustrating a step in the method for manufacturing the image sensor according to the first embodiment. [Figure 7]FIG. 7 is a schematic top view of an image sensor according to a modification of the first embodiment with a protective film removed. [Figure 8] FIG. 8 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film of an image sensor according to the second embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film of an image sensor according to a modification of the second embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film of an image sensor according to the third embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film of an image sensor according to a modification of the third embodiment. [Figure 12] FIG. 12 is an enlarged schematic cross-sectional view showing the vicinity of an end portion of the light detection film of the image sensor according to the first embodiment, including the semiconductor substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Summary of the Disclosure) A photoelectric conversion device according to an embodiment of the present disclosure includes a substrate, a photodetection film having a first surface facing the substrate and a second surface opposite to the first surface, a plurality of first electrodes provided between the substrate and the photodetection film, a second electrode provided between the substrate and the photodetection film and having a first portion overlapping the first surface and a second portion not overlapping the first surface when viewed from a normal direction of the substrate, a third electrode provided on the second surface of the photodetection film and having a third surface facing the second surface, wiring for conducting the second electrode and the third electrode, and a first conductive plug connected to the first portion of the second electrode and extending toward the substrate. The material of the first conductive plug is different from the material of the second electrode. The wiring continuously covers the side surface of the photodetection film and the second portion of the second electrode.

[0011] As a result, when viewed from the normal direction of the substrate, the first conductive plug overlaps the light detection film, and the light detection film functions as a protective film for the first conductive plug, which makes it easier to protect the first conductive plug from substances that cause deterioration of characteristics, such as moisture and oxygen, thereby suppressing deterioration of the characteristics of the photoelectric conversion device.

[0012] Also, for example, a photoelectric conversion device according to one embodiment of the present disclosure may further include a multilayer wiring structure disposed between the substrate and the photodetection film and including a plurality of interlayer insulating layers, and the first conductive plug may pass through the plurality of interlayer insulating layers.

[0013] This allows the wiring layers to be multi-layered, so that the area occupied by the wiring layers when the substrate is viewed in plan can be reduced, and the increase in element size can be suppressed.

[0014] Furthermore, for example, in the photoelectric conversion device according to one aspect of the present disclosure, a material of the wiring may have higher corrosion resistance than the material of the first conductive plug.

[0015] As a result, the wiring is formed using a material with high corrosion resistance, which enhances the protection performance of the first conductive plug and the light detection film, thereby suppressing deterioration in the quality and performance of the photoelectric conversion device.

[0016] Also, for example, in a photoelectric conversion device according to one embodiment of the present disclosure, the planar shape of the photodetection film when viewed from the normal direction of the substrate may have a recess, the second portion of the second electrode may overlap the recess when viewed from the normal direction of the substrate, and the wiring may be connected to the second portion of the second electrode in the recess.

[0017] This allows a long distance to be secured from the functional region, in which the multiple first electrodes are provided, to the side of the light detection film. Since there is a risk that the film quality at the end of the light detection film may be deteriorated during the etching process, by securing a long distance from the functional region to the side of the light detection film, the end can be avoided from being used as the functional region. This allows the quality and performance of the photoelectric conversion device to be improved. The functional region is an area for performing light detection, and corresponds to a pixel area when the photoelectric conversion device is an image sensor, for example.

[0018] Also, for example, a photoelectric conversion device according to one embodiment of the present disclosure may further include a plurality of second conductive plugs each in contact with the plurality of first electrodes and extending toward the substrate, and a peripheral circuit located between the first conductive plugs and the second conductive plugs when viewed from the normal direction of the substrate.

[0019] This makes it possible to effectively utilize the region between the first conductive plug and the second conductive plug, thereby preventing the element size from becoming too large.

[0020] Also, for example, in a photoelectric conversion device according to one embodiment of the present disclosure, the entire connection portion of the second electrode with the first conductive plug may be included in the one part, and the first conductive plug may be connected to a wiring layer included in a multilayer wiring structure disposed between the substrate and the photodetection film, or an electrical element provided on the substrate.

[0021] This allows the first conductive plug to be completely covered with the light detection film, thereby improving the protection performance of the first conductive plug, and thus suppressing deterioration in the quality and performance of the photoelectric conversion device.

[0022] Furthermore, for example, in the photoelectric conversion device according to one aspect of the present disclosure, the first electrode may be in contact with the first surface, and the second electrode may be provided in the same layer as the first electrode.

[0023] This allows the first electrode and the second electrode to be provided in the same layer, making it possible to prevent the height of the photovoltaic device from increasing. Also, the first electrode and the second electrode can be formed in the same process, making it possible to easily manufacture the photovoltaic device by reducing the number of processes.

[0024] Also, for example, in a photoelectric conversion device according to one embodiment of the present disclosure, the third electrode may have a fourth surface opposite to the third surface, and the wiring may continuously cover the fourth surface of the third electrode, a side surface of the photodetection film, and the second portion of the second electrode.

[0025] With this, since the wiring is in contact with the light detection film, it is possible to further suppress the increase in element size.

[0026] Also, for example, a photoelectric conversion device according to one embodiment of the present disclosure may further include a plurality of stacked structures, each of which includes the light detection film and the third electrode, and each of the plurality of stacked structures may be stacked on top of each other in the normal direction of the substrate.

[0027] This allows, for example, each of the multiple light detection films to detect a different wavelength band of light, allowing the detection results to be used for various purposes.

[0028] Furthermore, for example, in the photoelectric conversion device according to one aspect of the present disclosure, an end portion of each of the plurality of stacked structures may be provided in a stepped shape.

[0029] This ensures a sufficient contact area between the third electrode and the wiring, thereby preventing unnecessary voltage drops at the contact area, thereby improving the quality and performance of the photoelectric conversion device.

[0030] Furthermore, for example, in the photoelectric conversion device according to one aspect of the present disclosure, the side surfaces of the plurality of stacked structures may be flat across the plurality of stacked structures.

[0031] This makes it possible to further prevent the element size from becoming large, since the side surfaces of the electrode and the light detection film are flush with each other.

[0032] Furthermore, for example, in the photoelectric conversion device according to the aspect of the present disclosure, the wiring may have a film shape.

[0033] In this way, since the wiring having a film shape thinner than the through electrode covers the side surface of the light detection film, it is possible to suppress the increase in element size. Thus, according to this aspect, it is possible to realize a high-quality and high-performance photoelectric conversion device by suppressing the increase in element size.

[0034] In the present disclosure, all or part of a circuit, unit, device, member or part, or all or part of a functional block in a block diagram may be implemented by one or more electronic circuits including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). The LSI or IC may be integrated into one chip, or may be configured by combining multiple chips. For example, functional blocks other than memory elements may be integrated into one chip. Here, although it is called an LSI or an IC, the name may change depending on the degree of integration, and it may be called a system LSI, a VLSI (very large scale integration), or an ULSI (ultra large scale integration). A Field Programmable Gate Array (FPGA), which is programmed after the manufacture of the LSI, or a reconfigurable logic device, which can reconfigure the junction relationship inside the LSI or set up the circuit partition inside the LSI, can also be used for the same purpose.

[0035] Furthermore, all or part of the functions or operations of a circuit, unit, device, member, or section can be executed by software processing. In this case, the software is recorded in one or more non-transitory recording media such as ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified in the software are executed by the processor and peripheral devices. The system or device may include one or more non-transitory recording media on which the software is recorded, a processor, and necessary hardware devices, such as interfaces.

[0036] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0037] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component arrangement and connection, manufacturing process, and manufacturing process sequence shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, components that are not described in the independent claims are described as optional components.

[0038] In addition, each figure is a schematic diagram and is not necessarily illustrated precisely. Therefore, for example, the scales in each figure do not necessarily match. In addition, in each figure, substantially the same configurations are given the same reference numerals, and duplicated explanations are omitted or simplified.

[0039] Furthermore, in this specification, terms indicating the relationship between elements, such as flush, terms indicating the shape of an element, such as rectangle, and numerical ranges are not expressions that only express a strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about a few percent.

[0040] In this specification, the terms "upper" and "lower" do not refer to the upper direction (vertically upward) and lower direction (vertically downward) in absolute spatial recognition, but are used as terms defined by a relative positional relationship based on the stacking order in a stacked configuration. The terms "upper" and "lower" are applied not only to the case where two components are arranged with a gap between them and another component exists between the two components, but also to the case where two components are arranged closely together and are in contact with each other.

[0041] (Embodiment 1) [Overview of imaging devices including image sensors] First, an image pickup device including an image sensor according to the present embodiment will be generally described.

[0042] Fig. 1 is a schematic diagram showing a circuit configuration of an image pickup device 100 according to the present embodiment. As shown in Fig. 1, the image pickup device 100 is an example of a photoelectric conversion device, and includes an image sensor 101 including a plurality of pixels 14, and peripheral circuits.

[0043] A plurality of pixels 14 are arranged two-dimensionally, i.e., in row and column directions, on a semiconductor substrate to form a pixel region. The image sensor 101 may be a line sensor. In that case, the plurality of pixels 14 may be arranged in a line. In this specification, the row direction and the column direction refer to the directions in which the rows and columns extend, respectively. Specifically, the vertical direction is the column direction, and the horizontal direction is the row direction.

[0044] Each pixel 14 includes a photodetection unit 10 and a charge detection circuit 25. The photodetection unit 10 includes a pixel electrode 50, a photodetection film 51, and a transparent electrode 52. A specific configuration of the photodetection unit 10 will be described later. The charge detection circuit 25 includes an amplification transistor 11, a reset transistor 12, and an address transistor 13.

[0045] The imaging device 100 includes a voltage control element for applying a predetermined voltage to the transparent electrode 52. The voltage control element includes, for example, a voltage control circuit, a voltage generation circuit such as a constant voltage source, and a voltage reference line such as a ground line. The voltage applied by the voltage control element is called a control voltage. In this embodiment, the imaging device 100 includes a voltage control circuit 30 as the voltage control element.

[0046] The voltage control circuit 30 may generate a constant control voltage, or may generate a plurality of control voltages with different values. For example, the voltage control circuit 30 may generate a control voltage with two or more different values, or may generate a control voltage that changes continuously within a predetermined range. The voltage control circuit 30 determines the value of the control voltage to be generated based on a command from an operator who operates the imaging device 100, or a command from another control unit or the like provided in the imaging device 100, and generates a control voltage of the determined value. The voltage control circuit 30 is provided outside the photosensitive region as a part of the peripheral circuit.

[0047] For example, the voltage control circuit 30 generates two or more different control voltages and applies the control voltages to the transparent electrode 52. This changes the spectral sensitivity characteristics of the light detection film 51. This change in the spectral sensitivity characteristics includes a spectral sensitivity characteristic in which the sensitivity of the light detection film 51 becomes zero to the light to be detected. As a result, for example, in the imaging device 100, while the pixels 14 are reading out the detection signals row by row, the voltage control circuit 30 applies a control voltage to the transparent electrode 52 that makes the sensitivity of the light detection film 51 zero. This makes it possible to reduce the influence of light incident when reading out the detection signals to almost zero. Therefore, even if the detection signals are read out substantially row by row, a global shutter operation can be realized.

[0048] In this embodiment, as shown in Fig. 1, the voltage control circuit 30 applies a control voltage to the transparent electrodes 52 of the pixels 14 arranged in the row direction via the counter electrode signal line 16. As a result, the voltage control circuit 30 changes the voltage between the pixel electrodes 50 and the transparent electrodes 52, and switches the spectral sensitivity characteristics in the light detection unit 10. Alternatively, the voltage control circuit 30 may realize an electronic shutter operation by applying a control voltage so as to obtain a spectral sensitivity characteristic in which the sensitivity to light becomes zero at a predetermined timing during imaging. The voltage control circuit 30 may also apply a control voltage to the pixel electrodes 50.

[0049] When light is irradiated onto the photodetection unit 10, in order to accumulate electrons as signal charges in the pixel electrode 50, the pixel electrode 50 is set to a higher potential than the transparent electrode 52. At this time, the direction of movement of electrons is opposite to the direction of movement of holes, so a current flows from the pixel electrode 50 to the transparent electrode 52. Also, when light is irradiated onto the photodetection unit 10, in order to accumulate holes as signal charges in the pixel electrode 50, the pixel electrode 50 is set to a lower potential than the transparent electrode 52. At this time, a current flows from the transparent electrode 52 to the pixel electrode 50.

[0050] The pixel electrode 50 is connected to the gate electrode of the amplifier transistor 11, and the signal charge collected by the pixel electrode 50 is stored in a charge storage node 24 located between the pixel electrode 50 and the gate electrode of the amplifier transistor 11. In this embodiment, the signal charge is a hole. Alternatively, the signal charge may be an electron.

[0051] The signal charge stored in the charge storage node 24 is applied to the gate electrode of the amplifying transistor 11 as a voltage according to the amount of the signal charge. The amplifying transistor 11 is included in the charge detection circuit 25, and amplifies the voltage applied to the gate electrode. The address transistor 13 selectively reads out the amplified voltage as the signal voltage. The address transistor 13 is also called a row selection transistor. The reset transistor 12 has one of its source electrode and drain electrode connected to the pixel electrode 50, and resets the signal charge stored in the charge storage node 24. In other words, the reset transistor 12 resets the potentials of the gate electrode of the amplifying transistor 11 and the pixel electrode 50.

[0052] In order to selectively perform the above-mentioned operations in the multiple pixels 14, the imaging device 100 includes a power supply wiring 21, a vertical signal line 17, an address signal line 26, and a reset signal line 27. These wirings and signal lines are connected to the pixels 14, respectively. Specifically, the power supply wiring 21 is connected to one of the source electrode and the drain electrode of the amplification transistor 11. The vertical signal line 17 is connected to the other of the source electrode and the drain electrode of the address transistor 13, that is, the one not connected to the charge storage node 24. The address signal line 26 is connected to the gate electrode of the address transistor 13. In addition, the reset signal line 27 is connected to the gate electrode of the reset transistor 12.

[0053] The peripheral circuits include at least a part of electric circuits represented by a vertical scanning circuit 15, a horizontal signal readout circuit 20, a plurality of column signal processing circuits 19, a plurality of load circuits 18, a plurality of differential amplifiers 22, and a voltage control circuit 30. The vertical scanning circuit 15 is also called a row scanning circuit. The horizontal signal readout circuit 20 is also called a column scanning circuit. The column signal processing circuit 19 is also called a row signal storage circuit. The differential amplifier 22 is also called a feedback amplifier.

[0054] The vertical scanning circuit 15 is connected to an address signal line 26 and a reset signal line 27, and selects a plurality of pixels 14 arranged in each row on a row-by-row basis, reads out the signal voltage, and resets the potential of the pixel electrode 50. The power supply wiring 21 supplies a predetermined power supply voltage to each pixel 14. The horizontal signal readout circuit 20 is electrically connected to a plurality of column signal processing circuits 19. The column signal processing circuits 19 are electrically connected to the pixels 14 arranged in each column via vertical signal lines 17 corresponding to each column. The load circuits 18 are electrically connected to each vertical signal line 17. The load circuits 18 and the amplifying transistors 11 form a source follower circuit.

[0055] A plurality of differential amplifiers 22 are provided corresponding to each column. The negative input terminals of the differential amplifiers 22 are connected to the corresponding vertical signal lines 17. The output terminals of the differential amplifiers 22 are connected to the pixels 14 via the feedback lines 23 corresponding to each column.

[0056] The vertical scanning circuit 15 applies a row selection signal, which controls the on and off of the address transistor 13, to the gate electrode of the address transistor 13 via the address signal line 26. This causes the row to be read out to be scanned and selected. A signal voltage is read out from the pixels 14 in the selected row to the vertical signal line 17. The vertical scanning circuit 15 also applies a reset signal, which controls the on and off of the reset transistor 12, to the gate electrode of the reset transistor 12 via the reset signal line 27. This causes the row of the pixels 14 to be subjected to the reset operation to be selected. The vertical signal line 17 transmits the signal voltage read out from the pixels 14 selected by the vertical scanning circuit 15 to the column signal processing circuit 19.

[0057] The column signal processing circuit 19 performs noise suppression signal processing, such as correlated double sampling, and analog-to-digital conversion (AD conversion).

[0058] The horizontal signal read circuit 20 sequentially reads out signals from the multiple column signal processing circuits 19 to a horizontal common signal line .

[0059] The differential amplifier 22 is connected to the other of the drain and source electrodes of the reset transistor 12, which is not connected to the pixel electrode 50, via a feedback line 23. Therefore, when the address transistor 13 and the reset transistor 12 are in a conductive state, the differential amplifier 22 receives the output value of the address transistor 13 at its negative terminal. The differential amplifier 22 performs a feedback operation so that the gate potential of the amplifying transistor 11 becomes a predetermined feedback voltage. At this time, the output voltage value of the differential amplifier 22 is 0V or a positive voltage close to 0V. The feedback voltage means the output voltage of the differential amplifier 22.

[0060] A detailed device structure of the pixel 14 of the imaging device 100 will be described below with reference to Fig. 2. Fig. 2 is a cross-sectional view that typically illustrates a cross-section of the device structure of the pixel 14 of the imaging device 100 according to the present embodiment.

[0061] 2, the pixel 14 includes a semiconductor substrate 31, a charge detection circuit 25 (not shown), and a photodetector 10. The semiconductor substrate 31 is, for example, a p-type silicon substrate. The charge detection circuit 25 detects a signal charge captured by the pixel electrode 50 and outputs a signal voltage. The charge detection circuit 25 includes an amplification transistor 11, a reset transistor 12, and an address transistor 13, and is formed on the semiconductor substrate 31.

[0062] Each of the amplification transistor 11, the reset transistor 12, and the address transistor 13 is an example of an electric element formed on the semiconductor substrate 31. Each of the amplification transistor 11, the reset transistor 12, and the address transistor 13 is, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Specifically, each of the amplification transistor 11, the reset transistor 12, and the address transistor 13 is an n-channel MOSFET, but may be a p-channel MOSFET.

[0063] The amplifier transistor 11 has n-type impurity regions 41C and 41D, a gate insulating layer 38B, and a gate electrode 39B. The n-type impurity regions 41C and 41D are formed in the semiconductor substrate 31, and function as a drain or a source, respectively. The gate insulating layer 38B is located on the semiconductor substrate 31. The gate electrode 39B is located on the gate insulating layer 38B.

[0064] The reset transistor 12 has n-type impurity regions 41A and 41B, a gate insulating layer 38A, and a gate electrode 39A. The n-type impurity regions 41A and 41B are formed in the semiconductor substrate 31, and function as a drain and a source, respectively. The gate insulating layer 38A is located on the semiconductor substrate 31. The gate electrode 39A is located on the gate insulating layer 38A.

[0065] The address transistor 13 has n-type impurity regions 41D and 41E, a gate insulating layer 38C, and a gate electrode 39C. The n-type impurity regions 41D and 41E are formed in the semiconductor substrate 31, and function as a drain or a source, respectively. The gate insulating layer 38C is located on the semiconductor substrate 31. The gate electrode 39C is located on the gate insulating layer 38C.

[0066] The gate insulating layers 38A, 38B, and 38C are formed using an insulating material, and have, for example, a single-layer structure or a multilayer structure of a silicon oxide film or a silicon nitride film.

[0067] The gate electrodes 39A, 39B, and 39C are each formed using a conductive material. For example, the gate electrodes 39A, 39B, and 39C are formed using polysilicon to which impurities are added to make them conductive. Alternatively, the gate electrodes 39A, 39B, and 39C may be formed using a metal material such as copper.

[0068] The n-type impurity regions 41A, 41B, 41C, 41D, and 41E are formed by doping the semiconductor substrate 31 with an n-type impurity such as phosphorus (P) by ion implantation or the like. In the example shown in FIG. 2, the n-type impurity region 41D is shared by the amplification transistor 11 and the address transistor 13. This connects the amplification transistor 11 and the address transistor 13 in series. The n-type impurity region 41D may be separated into two n-type impurity regions. These two n-type impurity regions may be electrically connected via a wiring layer.

[0069] In the semiconductor substrate 31, an element isolation region 42 is provided between adjacent pixels 14 and between the amplification transistor 11 and the reset transistor 12. The element isolation region 42 electrically isolates adjacent pixels 14. In addition, leakage of signal charges accumulated in the charge accumulation node 24 is suppressed.

[0070] A multi-layer wiring structure is provided on the upper surface of the semiconductor substrate 31. The multi-layer wiring structure includes a plurality of interlayer insulating layers, one or more wiring layers, one or more plugs, and one or more contact plugs. Specifically, interlayer insulating layers 43A, 43B, and 43C are laminated on the upper surface of the semiconductor substrate 31. Contact plugs 45A and 45B, a wiring 46A, and a conductive plug 47A are embedded in the interlayer insulating layer 43A. A wiring 46B and a conductive plug 47B are embedded in the interlayer insulating layer 43B. A wiring 46C and a conductive plug 47C are embedded in the interlayer insulating layer 43C.

[0071] The contact plug 45A is connected to the n-type impurity region 41B of the reset transistor 12. The contact plug 45B is connected to the gate electrode 39B of the amplification transistor 11. The wiring 46A connects the contact plug 45A and the contact plug 45B. This electrically connects the n-type impurity region 41B of the reset transistor 12 to the gate electrode 39B of the amplification transistor 11.

[0072] Moreover, the wiring 46A is connected to the pixel electrode 50 via the conductive plugs 47A, 47B, and 47C, and the wirings 46B and 46C. As a result, the n-type impurity region 41B, the gate electrode 39B, the contact plugs 45A and 45B, the wirings 46A, 46B, and 46C, the conductive plugs 47A, 47B, and 47C, and the pixel electrode 50 configure the charge storage node 24.

[0073] 2, the multi-layer wiring structure may include a plurality of wirings 48B and 48C that are not directly and electrically connected to the pixel electrode 50. For example, the wiring 48B is located in the same layer as the wiring 46B and is embedded in the interlayer insulating layer 43B. The wiring 48C is located in the same layer as the wiring 46C and is embedded in the interlayer insulating layer 43C. The wirings 48B and 48C each function as, for example, a part of the counter electrode signal line 16, the vertical signal line 17, the power supply line 21, the feedback line 23, the address signal line 26, or the reset signal line 27. At least one of the wirings 48B and 48C may be connected to a power supply through-wire 62, which will be described later. At least one of the wirings 48B and 48C may be provided in the peripheral region, not in the pixel region.

[0074] The light detection section 10 is provided on the interlayer insulating layer 43C. The light detection section 10 includes a transparent electrode 52, a light detection film 51, and a pixel electrode 50 located closer to the semiconductor substrate 31 than the transparent electrode 52. The light detection film 51 is sandwiched between the transparent electrode 52 and the pixel electrode 50. The light detection section 10 also includes an insulating layer 53 formed on at least a part of the upper surface of the transparent electrode 52. The light detection section 10 further includes a protective film 54.

[0075] 2, the pixel 14 includes a color filter 55 above the transparent electrode 52 of the light detection unit 10. Furthermore, the pixel 14 includes a microlens 56 on the color filter 55. Note that the pixel 14 does not necessarily need to include the insulating layer 53, the protective film 54, the color filter 55, and the microlens 56.

[0076] The structure of each of the photodetector sections 10 of the multiple pixels 14 and the vicinity of the ends of the photodetector film 51 will be described below with reference to FIGS. 3, 4 and 5. FIG.

[0077] Fig. 3 is a schematic cross-sectional view of image sensor 101 according to the present embodiment. Fig. 4 is a schematic top view of image sensor 101 according to the present embodiment with protective film 54 removed. Fig. 5 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of light detection film 51 of image sensor 101 according to the present embodiment.

[0078] In the following figures, except for Fig. 12, the interlayer insulating layers 43A, 43B, and 43C shown in Fig. 2 are collectively referred to as the interlayer insulating layer 43. The conductive plugs 47A, 47B, and 47C are collectively referred to as the conductive plug 47. The semiconductor substrate 31, as well as the transistors, wiring, plugs, and the like, are not shown.

[0079] In this specification, the configuration below the light detection film 51 may be collectively referred to as the circuit section. Specifically, the circuit section includes the semiconductor substrate 31 and the interlayer insulating layer 43, as well as the transistors, wiring, plugs, and the like formed on or inside these. For example, the circuit section also includes the pixel electrodes 50 and the control electrodes 60.

[0080] 4, in order to make the shapes of the light detection film 51, the control electrode 60, and the connection portion 61 easier to understand, they are each shaded with different types of oblique lines. In this case, the light detection film 51 is not shaded in the portion that overlaps with the pixel electrode 50, the control electrode 60, and the connection portion 61. Similarly, the connection portion 61 is not shaded in the portion that overlaps with the control electrode 60. The same applies to FIG. 7, which will be described later.

[0081] As described above, the image sensor 101 includes a plurality of pixels 14. Specifically, the image sensor 101 includes a plurality of pixel electrodes 50, a light detection film 51, and a transparent electrode 52, as shown in Figures 3, 4, and 5.

[0082] In this embodiment, the light detection film 51 and the transparent electrode 52 of each pixel 14 are connected to the light detection film 51 and the transparent electrode 52 of the adjacent pixel 14, respectively, to form an integrated light detection film 51 and transparent electrode 52. The light detection film 51 may be separated for each pixel 14. The transparent electrode 52 may be integrally connected for each row or column of the two-dimensionally arranged pixels 14. In contrast, the pixel electrode 50 of each pixel 14 is not connected to the pixel electrode 50 of the adjacent pixel 14 and is independent. In other words, one pixel electrode 50 is provided for each pixel 14.

[0083] The image sensor 101 further includes a control electrode 60, a connection portion 61, and a power supply through wire 62. The control electrode 60, the connection portion 61, and the power supply through wire 62 form a part of the counter electrode signal line 16.

[0084] The pixel electrodes 50 are an example of a plurality of first electrodes provided on the lower surface 51a side of the light detection film 51. The pixel electrodes 50 are arranged one-dimensionally or two-dimensionally and embedded in the upper surface 43a of the interlayer insulating layer 43 so that the upper surface of each pixel electrode 50 is exposed. FIG. 4 shows an example in which a total of 30 pixel electrodes 50 are arranged in 5 rows and 6 columns, but the number of pixel electrodes 50 is not particularly limited. As shown in FIG. 3 and FIG. 5, each of the pixel electrodes 50 is in contact with the lower surface 51a of the light detection film 51. A conductive plug 47 is connected to each of the pixel electrodes 50. The conductive plug 47 is an example of a plurality of second conductive plugs extending toward the semiconductor substrate 31.

[0085] The conductive plug 47 and the power supply through wiring 62 are made of copper or silver.

[0086] The pixel electrodes 50 are formed using a conductive material such as a metal such as aluminum or copper, or polysilicon doped with impurities to provide conductivity. The pixel electrodes 50 may be formed using the same material as the control electrode 60 described below. The pixel electrodes 50 are, for example, the same size and shape as one another.

[0087] 3 and 5, the light detection film 51 has a lower surface 51a and an upper surface 51b. The lower surface 51a is an example of a first surface facing the semiconductor substrate 31. The upper surface 51b is an example of a second surface opposite to the lower surface 51a.

[0088] In this specification, "two surfaces facing each other" does not only mean that the two surfaces are directly opposite each other with no other components between them, but also means that there is another component between them. In other words, "facing each other" also includes cases where the two surfaces face each other with another component between them. "Facing each other" also means that the two surfaces face each other and are in contact with each other.

[0089] In this embodiment, the light detection film 51 is disposed on the upper surface 43a of the interlayer insulating layer 43 so as to cover the plurality of pixel electrodes 50 and the power supply through wiring 62. Specifically, as shown in FIG. 4, the light detection film 51 overlaps the plurality of pixel electrodes 50 and a part of the control electrode 60 when viewed from the normal direction of the semiconductor substrate 31. More specifically, the light detection film 51 contacts and covers each of the plurality of pixel electrodes 50 and the first portion 60a of the control electrode 60. Note that the view from the normal direction of the semiconductor substrate 31 will hereinafter be simply referred to as "top view."

[0090] The light detection film 51 photoelectrically converts the incident light to generate a signal charge according to the intensity of the incident light. The light detection film 51 is made of, for example, an organic semiconductor. The light detection film 51 may include one or more organic semiconductor layers. For example, the light detection film 51 may include a carrier transport layer that transports electrons or holes, and a blocking layer that blocks carriers, in addition to a photoelectric conversion layer that generates hole-electron pairs. These organic semiconductor layers may be made of organic p-type semiconductors and organic n-type semiconductors made of known materials. The light detection film 51 may be, for example, a mixed film of organic donor molecules and acceptor molecules, a mixed film of semiconducting carbon nanotubes and acceptor molecules, or a quantum dot-containing film.

[0091] The transparent electrode 52 is an example of a third electrode provided on the upper surface 51b side of the light detection film 51, and has a lower surface 52a and an upper surface 52b. The lower surface 52a is an example of a third surface facing the upper surface 51b of the light detection film 51. The upper surface 52b is an example of a fourth surface opposite the lower surface 52a.

[0092] The transparent electrode 52 is disposed on the upper surface 51b of the light detection film 51. Specifically, the transparent electrode 52 is provided in contact with the upper surface 51b so as to cover at least a region of the upper surface 51b of the light detection film 51 where the plurality of pixel electrodes 50 and the power supply through wiring 62 are provided. In the present embodiment, the transparent electrode 52 is formed to cover the entire upper surface 51b of the light detection film 51. For example, the shape of the transparent electrode 52 and the shape of the light detection film 51 are the same in a top view. As shown in FIG. 5, the side surface 52s of the transparent electrode 52 and the side surface 51s of the light detection film 51 are flush with each other. That is, there is no step between the side surface 52s of the transparent electrode 52 and the side surface 51s of the light detection film 51. The side surface 52s of the transparent electrode 52 and the side surface 51s of the light detection film 51 are flat across the side surface 52s of the transparent electrode 52 and the side surface 51s of the light detection film 51. Here, an example is shown in which the side surface 52s and the side surface 51s are parallel to the normal direction of the semiconductor substrate 31, but the side surface 52s and the side surface 51s may be inclined obliquely with respect to the normal direction.

[0093] The transparent electrode 52 is formed using a material that is transparent to the light to be detected and has electrical conductivity. For example, the transparent electrode 52 is formed using a transparent conductive semiconductor oxide film such as indium tin oxide (ITO), aluminum doped zinc oxide (AZO), or gallium doped zinc oxide (GZO). The transparent electrode 52 may be formed using other transparent conductive semiconductors, or may be formed using a thin metal film that is thin enough to transmit light.

[0094] In this embodiment, as shown in FIG. 4, the light detection film 51 and the transparent electrode 52 have a rectangular shape in top view. Two control electrodes 60 are arranged so as to overlap each of the sides 52e and 52f among the four sides 52c, 52d, 52e, and 52f of the transparent electrode 52. For this reason, the image sensor 101 includes two connection parts 61. The two connection parts 61 are provided so as to cover each of the sides 52e and 52f of the transparent electrode 52. Each of the two connection parts 61 is joined to the control electrode 60 and the side surface 52s of the transparent electrode 52, and electrically connects the control electrode 60 and the transparent electrode 52.

[0095] The insulating layer 53 is formed to cover at least a part of the upper surface 52b of the transparent electrode 52. The insulating layer 53 is provided in contact with the upper surface 52b so as to cover at least a region of the upper surface 52b of the transparent electrode 52 in which the plurality of pixel electrodes 50 and the power supply through wiring 62 are provided.

[0096] 5, in the present embodiment, a through hole 53a is provided in the insulating layer 53. The through hole 53a is a contact hole for electrically connecting the connection portion 61 and the transparent electrode 52. A part of the transparent electrode 52 is exposed in the through hole 53a.

[0097] The protective film 54 is provided on the upper surface 43 a of the interlayer insulating layer 43 , covering the connection portion 61 and the insulating layer 53 .

[0098] The insulating layer 53 and the protective film 54 are formed using a material having insulating properties. For example, the insulating layer 53 is formed of silicon oxide, silicon nitride, silicon oxynitride, or an organic or inorganic polymer material. The insulating layer 53 and the protective film 54 are transparent to light of a wavelength to be detected by the image sensor 101, for example.

[0099] The control electrode 60 is an example of a second electrode provided on the lower surface 51a side of the light detection film 51. As shown in Figs. 4 and 5, the control electrode 60 has a first portion 60a and a second portion 60b. The first portion 60a is a portion that overlaps with the lower surface 51a of the light detection film 51 in a top view. The second portion 60b is a portion that does not overlap with the lower surface 51a of the light detection film 51 in a top view. In other words, the second portion 60b is a portion that is exposed and not covered by the light detection film 51.

[0100] In this embodiment, the control electrode 60 is provided in the same layer as the multiple pixel electrodes 50. Specifically, the lower surface of the control electrode 60 and the lower surfaces of each of the multiple pixel electrodes 50 are at the same height from the semiconductor substrate 31. In addition, the upper surface of the control electrode 60 and the upper surfaces of each of the multiple pixel electrodes 50 are at the same height from the semiconductor substrate 31. The control electrode 60 and the multiple pixel electrodes 50 may be formed, for example, in the same process using the same material.

[0101] The control electrode 60 is formed, for example, using a material containing a metal, and has electrical conductivity and light shielding properties. For example, the control electrode 60 is formed of a metal film such as titanium, tantalum aluminum, tungsten, or aluminum with added silicon and copper (AlSiCu), or a metal film made of an alloy of these. Alternatively, the control electrode 60 may be formed of a metal nitride film such as titanium nitride, tantalum nitride, or tungsten nitride. Alternatively, the control electrode 60 may be formed of a metal carbide film such as titanium carbide, tantalum carbide, or tungsten carbide. The control electrode 60 may have a single-layer structure of the above-mentioned metal film or metal nitride film, or may have a laminated structure of multiple metal films or metal nitride films.

[0102] The control electrode 60 may be formed using a material that is more corrosion resistant than the power supply through wire 62. The material that is more corrosion resistant is, for example, a material that has low reactivity with oxygen and moisture.

[0103] Since the control electrode 60 is formed using a highly corrosion-resistant material, the power supply through wire 62 can be protected from oxygen gas and the like used in patterning the light detection film 51. Since oxidation of the power supply through wire 62 is suppressed, deterioration of the quality and characteristics of the image sensor 101 can be suppressed.

[0104] The connection portion 61 is an example of a wiring that electrically connects the control electrode 60 and the transparent electrode 52. In the present embodiment, the connection portion 61 is an example of a film-shaped wiring that continuously covers the side surface 51s of the light detection film 51 and the second portion 60b of the control electrode 60.

[0105] Specifically, the connection portion 61 joins the control electrode 60 exposed on the upper surface 43a of the interlayer insulating layer 43 to the side surface 52s of the transparent electrode 52. The connection portion 61 also covers the side surface 51s of the light detection film 51. The connection portion 61 also covers a part of the upper surface of the insulating layer 53 other than the area where the pixel electrodes 50 are provided. In other words, the connection portion 61 does not overlap any of the multiple pixel electrodes 50 in a top view.

[0106] Furthermore, a portion of the connection portion 61 is located within the through hole 53a and is physically and electrically connected to the transparent electrode 52. Specifically, the connection portion 61 covers a portion of the upper surface 52b of the transparent electrode 52 that is exposed within the through hole 53a. In this manner, the connection portion 61 contacts and continuously covers the upper surface 52b of the transparent electrode 52, the inside of the through hole 53a of the insulating layer 53, the upper surface and side surface 53s of the insulating layer 53, the side surface 52s of the transparent electrode 52, the side surface 51s of the light detection film 51, and the second portion 60b of the control electrode 60 in this order.

[0107] The bonding area between the connection portion 61 and the control electrode 60 may be larger or smaller than the bonding area between the connection portion 61 and the transparent electrode 52. The bonding area between the connection portion 61 and the control electrode 60 may be the same as the bonding area between the connection portion 61 and the transparent electrode 52. As shown in FIG. 4, in this embodiment, in a top view, the connection portion 61 is larger than the control electrode 60 and completely contains the control electrode 60. In other words, the connection portion 61 contacts and covers the entire second portion 60b of the control electrode 60.

[0108] The connection portion 61 is formed, for example, using a material containing a metal, and has electrical conductivity and light blocking properties. For example, the connection portion 61 is formed of a metal film such as titanium, aluminum, copper, tungsten, gold, silver, nickel, cobalt, or aluminum with added silicon and copper (AlSiCu), or a metal film made of an alloy of these. Alternatively, the connection portion 61 may be formed of a metal nitride film such as titanium nitride. Similarly to the control electrode 60, the connection portion 61 may have a single-layer structure of the above-mentioned metal film or metal nitride film, or may have a laminated structure of multiple metal films or metal nitride films.

[0109] The connection portion 61 may be formed using a material that is more corrosion resistant than the power supply through wiring 62. An example of a material that is more corrosion resistant is titanium nitride. An example of a material that is more corrosion resistant is a material that is less reactive to oxygen and moisture.

[0110] The power supply through wire 62 is an example of a first conductive plug that is connected to the first portion 60a of the control electrode 60 and extends toward the semiconductor substrate 31. In top view, as shown in FIG. 4, the power supply through wire 62 is located inside the first portion 60a. That is, the entire portion of the control electrode 60 that is connected to the power supply through wire 62 is included in the first portion 60a. The power supply through wire 62 is electrically connected to the voltage control circuit 30 shown in FIG.

[0111] As described above, in the image sensor 101 according to the present embodiment, the portion of the voltage application path from the control electrode 60 to the transparent electrode 52 that does not require translucency is wired at the connection portion 61. This makes it possible to apply a voltage to the transparent electrode 52 with low wiring resistance, and voltage fluctuations in the light detection film 51 are suppressed.

[0112] This realizes the image sensor 101 capable of more stable imaging. The image sensor 101 is also used in imaging devices for mobile devices that require lower power consumption. It is also possible to realize an imaging device that has a high-speed electronic shutter or can switch spectral sensitivity characteristics at higher speeds.

[0113] 3 and 5, a through wiring 62 for supplying power to the transparent electrode 52 is disposed directly below the light detection film 51, and a thin-film connection portion 61 is used as a wiring material for establishing an electrical connection to the transparent electrode 52. This eliminates the need to secure an area for arranging the through wiring on the side of the light detection film 51 solely for the purpose of supplying power to the transparent electrode 52. Furthermore, since the through wiring 62 for supplying power and the transparent electrode 52 are electrically connected by the minute thin-film connection portion 61, it is possible to suppress an increase in the size of the element.

[0114] [Manufacturing method] Next, a method for manufacturing image sensor 101 according to the present embodiment will be described with reference to Figures 6A to 6H. Figures 6A to 6H are cross-sectional views for explaining each step of the method for manufacturing image sensor 101 according to the present embodiment.

[0115] (A) The process of preparing the circuit part First, a circuit section is prepared as shown in Fig. 6A. Specifically, a semiconductor substrate 31 (not shown) on which an interlayer insulating layer 43 is formed is prepared. As described above, a plurality of pixel electrodes 50 and control electrodes 60 are provided on an upper surface 43a of the interlayer insulating layer 43. Furthermore, the power supply through wiring 62 is connected to the control electrode 60. More specifically, the circuit section has the structure shown in Fig. 2 for each pixel electrode 50, and can be fabricated using a known semiconductor device manufacturing method.

[0116] (B) Step of forming a light detection film Next, as shown in FIG. 6B, a light detection film 151 is formed on the upper surface 43a of the interlayer insulating layer 43 so as to cover the pixel electrodes 50 and the control electrode 60. The lower surface 151a of the light detection film 151 is in contact with the upper surface 43a of the interlayer insulating layer 43, the pixel electrodes 50, and the control electrode 60. The light detection film 151 can be formed by a spin coating method, an inkjet method, a die coating method, a spray coating method, a vacuum deposition method, a screen printing method, or the like. The light detection film 151 is patterned into a predetermined shape in a later process to become the light detection film 51 shown in FIG. 3.

[0117] (C) A process for forming a transparent conductive film Next, as shown in FIG. 6B, a transparent conductive film 152 is formed on the light detection film 151. The transparent conductive film 152 is formed on a region of the light detection film 151 where the multiple pixel electrodes 50 are provided. A lower surface 152a of the transparent conductive film 152 is in contact with an upper surface 151b of the light detection film 151. The transparent conductive film 152 is formed by, for example, a sputtering method. Note that the transparent conductive film 152 is patterned into a predetermined shape in a later process to become the transparent electrode 52 shown in FIG.

[0118] (D) Step of forming an insulating layer Next, as shown in FIG. 6B, an insulating layer 153 is formed on the transparent conductive film 152. The insulating layer 153 is formed on at least an area of ​​the transparent conductive film 152 where a plurality of pixel electrodes 50 are provided. The lower surface of the insulating layer 153 is in contact with the upper surface 152b of the transparent conductive film 152. The insulating layer 153 can be formed by, for example, an atomic layer deposition (ALD) method, a chemical vapor deposition (CVD) method, or a sputtering method. The insulating layer 153 will become the insulating layer 53 by being patterned into a predetermined shape in a later process.

[0119] (E) Patterning step Next, a part of the light detection film 151, a part of the transparent conductive film 152, and a part of the insulating layer 153 are removed, respectively, to thereby pattern the light detection film 151, the transparent conductive film 152, and the insulating layer 153. Specifically, as shown in FIG. 6C, a photosensitive resist 190 is formed on the insulating layer 153. For example, the photosensitive resist 190 is formed by a spin coating method. Next, the photosensitive resist 190 is exposed using a photomask and developed to form a resist pattern 191 having a predetermined pattern, as shown in FIG. 6D.

[0120] Next, the light detection film 151, the transparent conductive film 152, and the insulating layer 153 are etched using the resist pattern 191. The etching of each film is performed by, for example, dry etching.

[0121] For example, the insulating layer 153 and the transparent conductive film 152 are etched using a gas containing a halogen, such as fluorine, chlorine, bromine, or iodine. At this time, a gas containing at least one of the elements fluorine and chlorine may be used. Furthermore, the dry etching is performed using reactive etching (RIE) in which a gas is turned into plasma by plasma discharge, and the chemical species of the gas that has been turned into plasma reacts with the insulating layer 153 and the transparent conductive film 152. When the insulating layer 153 and the transparent conductive film 152 are formed using a material containing, for example, nitrogen or silicon, the insulating layer 153 and the transparent conductive film 152 can be efficiently etched by using these gases and etching methods.

[0122] On the other hand, the etching of the light detection film 151 is performed using a gas containing oxygen. Specifically, a chamber is filled with a gas containing oxygen, and a part of the light detection film 151 is oxidized by chemical etching using an oxidation reaction. Since the light detection film 151 contains a large amount of carbon, it can be removed as carbon oxide by an oxidation reaction with oxygen gas.

[0123] 6E, the light detection film 51, the transparent electrode 52, and the insulating layer 153 are formed in the desired shapes. A side surface 51s of the light detection film 51, a side surface 52s of the transparent electrode 52, and a side surface 53s of the insulating layer 53 are flush with each other.

[0124] At this time, the power supply through wire 62 is disposed at a position where it is completely covered by the light detection film 51. In addition, the second portion 60b, which is a part of the control electrode 60, is exposed.

[0125] Furthermore, in this embodiment, a part of insulating layer 53 is removed to form through hole 53a as shown in Fig. 6F. Specifically, a resist pattern (not shown) is formed to expose only the position of insulating layer 53 where through hole 53a is to be formed, and the exposed part of insulating layer 53 is removed using the resist pattern as a mask to form through hole 53a. Note that through hole 53a may be formed simultaneously with patterning of insulating layer 153. Through hole 53a is formed by, for example, dry etching, but may also be formed by wet etching.

[0126] (F) Step of forming a connection Next, a connection portion 61 is formed to electrically connect the side surface 52s of the transparent electrode 52 and the control electrode 60. Specifically, as shown in Fig. 6G, a conductive thin film 161 is formed over the entire upper surface 43a of the interlayer insulating layer 43 so as to contact and cover each of the upper surface of the insulating layer 53, the side surface 53s of the insulating layer 53, the side surface 52s of the transparent electrode 52, and the side surface 51s of the light detection film 51. The conductive thin film 161 can be formed by using a sputtering method, a vacuum deposition method, or the like.

[0127] Thereafter, a resist pattern (not shown) is formed to expose at least the region of the conductive thin film 161 where the pixel electrodes 50 are provided, and a part of the conductive thin film 161 is removed by etching using the formed resist pattern as a mask. As a result, as shown in FIG. 6H, a connection portion 61 is formed that is joined to the control electrode 60 on the upper surface 43a of the interlayer insulating layer 43 and is also joined to the side surface 52s and upper surface 52b of the transparent electrode 52. Since the connection portion 61 is formed on the outer periphery of the element, if the size of the connection portion 61 is large, it will cause the element size to become enlarged. Therefore, by forming the connection portion 61 from a conductive thin film, it is possible to form the connection portion 61 to have the minimum necessary size.

[0128] (G) Process for forming a protective film Next, when the image sensor 101 includes the protective film 54, the protective film 54 is formed on the upper surface 43a of the interlayer insulating layer 43, covering the connection portion 61 and the insulating layer 53, as shown in Fig. 3. In this way, the image sensor 101 shown in Fig. 3 is manufactured.

[0129] [Variations] Here, a modification of the first embodiment will be described.

[0130] Fig. 7 is a schematic top view of an image sensor 102 according to this modification with the protective film 54 removed. As shown in Fig. 7, the top view shapes of the light detection film 51, the transparent electrode 52, the control electrode 60, and the connection portion 61 are different from those in the first embodiment. The following description will focus on the differences from the first embodiment, and the description of the commonalities will be omitted or simplified.

[0131] 7, the light detection film 51 has a recess 51r in top view. In this modification, two recesses 51r are provided in the light detection film 51. The two recesses 51r are recessed from each of the sides 52e and 52f toward the center. In top view, the shape of the recess 51r is rectangular, but is not limited thereto.

[0132] The position where the recess 51r is provided is not particularly limited. For example, the recess 51r may be provided at at least one of the four vertices of the rectangle of the light detection film 51. In other words, the recess 51r may be provided by cutting out a corner of the rectangle. The shape of the recess 51r in top view may be a triangle, a semicircle, or the like.

[0133] In this modification, the second portion 60b of the control electrode 60 overlaps the recess 51r in a top view. The connection portion 61 is connected to the second portion 60b at the recess 51r.

[0134] In this manner, in this modification, by providing the second portion 60b in the recess 51r, it is possible to ensure a wiring path for supplying voltage from the control electrode 60 to the transparent electrode 52 while suppressing an increase in element size. Also, similarly to the second embodiment described below, it is possible to partially increase the distance from the side surface 51s of the light detection film 51 to the pixel electrode 50, thereby obtaining a high-performance and stable image sensor 101.

[0135] (Embodiment 2) Next, a second embodiment will be described.

[0136] Fig. 8 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of light detection film 251 of image sensor 201 according to the present embodiment. As shown in Fig. 8, image sensor 201 differs from image sensor 101 according to embodiment 1 in that it includes light detection film 251 instead of light detection film 51. The following description will focus on the differences from embodiment 1, and description of commonalities will be omitted or simplified.

[0137] The light detection film 251 has a larger area at the end where the pixel electrodes 50 are not provided, compared to the light detection film 51 according to embodiment 1. Specifically, in top view, the distance D between the end of the pixel electrode 250, which is the pixel electrode 50 located at the edge among the multiple pixel electrodes 50, and the side surface 251s of the light detection film 251 is long.

[0138] 8, the distance D is expressed as the sum of the width D1 of the first portion 60a of the control electrode 60 and the distance D2 between the pixel electrode 250 and the control electrode 60. In this case, the distance D2 is longer than, for example, the width D3 of the pixel electrode 250. The distance D2 may be longer than twice the width D3.

[0139] The distance D is, for example, longer than the end of the light detection film 251 where the film quality may deteriorate. As in the first embodiment, oxygen plasma can be used to etch the light detection film 251. However, the light detection film 251 has a tendency to deteriorate in performance when exposed to oxygen or moisture. Therefore, the light detection function is likely to deteriorate at the end of the light detection film 251 etched with oxygen plasma, and the pixel electrode 250 may be adversely affected by the performance deterioration.

[0140] According to the image sensor 201 of this embodiment, the distance D from the side surface 251s of the light detection film 251 to the pixel electrode 250 can be sufficiently ensured, so that a high-performance and stable image sensor 201 can be obtained.

[0141] [Variations] Next, a modification of the second embodiment will be described.

[0142] Fig. 9 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film 251 of an image sensor 301 according to this modification. As shown in Fig. 9, the image sensor 301 differs from the image sensor 201 according to the second embodiment in that a peripheral circuit 370 is located between a conductive plug 47 and a power supply through wiring 62. The following description will focus on the differences from the second embodiment, and description of the commonalities will be omitted or simplified.

[0143] The peripheral circuit 370 is, for example, at least one of the vertical scanning circuit 15, the horizontal signal readout circuit 20, the voltage control circuit 30, the load circuit 18, and the column signal processing circuit 19 shown in Fig. 1. Note that, although Fig. 9 shows the peripheral circuit 370 being located in the interlayer insulating layer 43, a part or the whole of the peripheral circuit 370 may be provided in the semiconductor substrate 31. That is, in this modification, the peripheral circuit 370 is located between the conductive plug 47 connected to the pixel electrode 250 and the power supply through wiring 62 in a top view.

[0144] This makes it possible to effectively utilize the end region provided to ensure the distance D from the side surface 251s of the light detection film 251 to the pixel electrode 250. By providing the peripheral circuit 370 between the conductive plug 47 and the power supply through wiring 62, other spaces can be reduced, and the increase in element size can be suppressed.

[0145] (Embodiment 3) Next, a third embodiment will be described.

[0146] FIG. 10 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of the light detection film 51 of the image sensor 401 according to the present embodiment. As shown in FIG. 10, the image sensor 401 includes a plurality of laminated structures of the light detection film 51, the transparent electrode 52, and the insulating layer 53, as compared with the image sensor 101 according to the first embodiment. Specifically, the image sensor 401 includes three laminated structures 451a, 451b, and 451c. The three laminated structures 451a, 451b, and 451c are laminated in the normal direction of the semiconductor substrate 31. Furthermore, the image sensor 401 includes a connection portion 461 instead of the connection portion 61. In the following, differences from the first embodiment will be mainly described, and descriptions of commonalities will be omitted or simplified.

[0147] In the present embodiment, the ends of the three laminated structures 451a, 451b, and 451c are provided in a stepped shape. Specifically, at least a part of the end of the upper surface 52b of the transparent electrode 52 of each of the three laminated structures 451a, 451b, and 451c does not overlap with other laminated structures in top view.

[0148] For example, the upper surface 52b of the transparent electrode 52 of the stacked structure 451a, which is the closest to the semiconductor substrate 31, i.e., the lowest stacked structure, does not overlap with the stacked structures 451b and 451c in top view. The upper surface 52b of the transparent electrode 52 of the stacked structure 451b located in the middle does not overlap with the stacked structure 451c in top view. The insulating layer 53 of each of the three stacked structures 451a, 451b, and 451c is provided with a through hole 53a for exposing a part of the upper surface 52b of the transparent electrode 52. The through holes 53a of each of the three stacked structures 451a, 451b, and 451c do not overlap with each other in top view.

[0149] The light detection films 51 included in each of the three stacked structures 451a, 451b, and 451c have different wavelengths of light to be detected. For example, the light detection films 51 included in each of the three stacked structures 451a, 451b, and 451c detect red light, green light, and blue light, respectively, and generate signal charges according to the intensity of each light. This allows the image sensor 401 to generate a color image without providing a color filter 55.

[0150] The connection portion 461 contacts and covers the upper surface 52b of the transparent electrode 52 included in each of the three laminated structures 451a, 451b, and 451c, and the side surfaces of each of the three laminated structures 451a, 451b, and 451c. Specifically, the connection portion 461 contacts and covers the upper surface 52b of the transparent electrode 52 of the uppermost laminated structure 451c, the side surface of the laminated structure 451c, the upper surface 52b of the transparent electrode 52 of the middle laminated structure 451b, the side surface of the laminated structure 451b, the upper surface 52b of the transparent electrode 52 of the lowermost laminated structure 451a, the side surface of the laminated structure 451a, and the second portion 60b of the control electrode 60 in this order. The side surfaces of each of the laminated structures 451c, 451b, and 451a include a side surface 53s of the insulating layer 53, a side surface 52s of the transparent electrode 52, and a side surface 51s of the light detecting film 51.

[0151] Although not shown, a plurality of pixel electrodes 50 are connected to the lower surface 51a of each of the light detection films 51 of the three stacked structures 451a, 451b, and 451c. A conductive plug 47 is connected to the lower surface of each of the plurality of pixel electrodes 50. In this case, the conductive plug 47 connected to the pixel electrode 50 for the light detection film 51 of the uppermost stacked structure 451c penetrates the middle stacked structure 451b and the lowermost stacked structure 451a. In addition, the conductive plug 47 connected to the pixel electrode 50 for the light detection film 51 of the middle stacked structure 451b penetrates the lowermost stacked structure 451a. With this configuration, the light detection film 51 of each stacked structure can perform photoelectric conversion at the part connected to the pixel electrode 50 and accumulate signal charges in the charge accumulation node 24 via the pixel electrode 50 and the conductive plug 47.

[0152] As described above, according to this embodiment, the wavelength band of light detected by each of the multiple light detection films 51 can be made different, so that the detection results can be used for various purposes.

[0153] In the present embodiment, an example in which three laminated structures are laminated has been shown, but two laminated structures may be laminated, or four or more laminated structures may be laminated. For example, when two laminated structures are laminated, the light detection film 51 of one laminated structure may detect infrared light, and the light detection film 51 of the other laminated structure may detect visible light. The number of laminated structures and the wavelength of light to be detected are not particularly limited.

[0154] [Variations] Next, a modification of the third embodiment will be described.

[0155] Fig. 11 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of a light detection film 51 of an image sensor 501 according to this modification. As shown in Fig. 11, the image sensor 501 is different from the image sensor 401 according to the third embodiment in that the side surfaces of the three laminated structures 451a, 451b, and 451c are flush with each other. The following description will focus on the differences from the third embodiment, and the description of the commonalities will be omitted or simplified.

[0156] In this modification, the side surfaces of the three laminated structures 451a, 451b, and 451c are flush with each other, that is, the side surfaces of the three laminated structures 451a, 451b, and 451c are flat across the three laminated structures 451a, 451b, and 451c, so that the upper surfaces 52b of the transparent electrodes 52 of the laminated structures other than the uppermost laminated structure 451c are covered by the laminated structures located above. Therefore, in this modification, a voltage is supplied to each of the transparent electrodes 52 of the middle laminated structure 451b and the lowermost laminated structure 451a through the side surfaces 52s of the transparent electrodes 52. A through hole 53a is provided in the insulating layer 53 of the uppermost laminated structure 451c, exposing a part of the upper surface 52b of the transparent electrode 52.

[0157] The image sensor 501 includes a connection portion 561 instead of the connection portion 461. The connection portion 561 contacts and covers the side surfaces of each of the three laminated structures 451a, 451b, and 451c. Specifically, the connection portion 561 contacts and covers the upper surface 52b of the transparent electrode 52 of the uppermost laminated structure 451c, the side surface of the laminated structure 451c, the side surface of the middle laminated structure 451b, the side surface of the lowermost laminated structure 451a, and the second portion 60b of the control electrode 60 in this order.

[0158] As described above, according to this modification, since the side surfaces of each laminate structure are flush with each other, it is possible to further suppress the increase in element size.

[0159] The insulating layer 53 of the uppermost laminated structure 451c does not have to have the through-hole 53a. A voltage may be supplied to each of the transparent electrodes 52 of the three laminated structures 451a, 451b, and 451c via the side surface 52s of the transparent electrode 52.

[0160] Fig. 12 is a schematic cross-sectional view showing an enlarged view of the vicinity of an end of the light detection film 51 of the image sensor 101 according to the first embodiment, including the semiconductor substrate 31. Fig. 12 differs from Fig. 5 in showing interlayer insulating layers 43A, 43B, and 43C and the semiconductor substrate 31. Fig. 12 further shows the reset transistor 12, wiring, plugs, etc. The following mainly describes the differences from Fig. 5, and the description of the commonalities will be omitted or simplified.

[0161] The pixel electrode 50 and the control electrode 60 are provided between the light detection film 51 and the semiconductor substrate 31. When viewed from the normal direction of the semiconductor substrate 31, the power supply through wire 62 overlaps with the light detection film 51, so that the light detection film 51 functions as a protective film for the power supply through wire 62. This makes it easier to protect the power supply through wire 62, which is the first conductive plug, from substances such as moisture and oxygen that cause deterioration of characteristics, so that deterioration of the characteristics of the photoelectric conversion device can be suppressed.

[0162] A multi-layer wiring structure is provided on the upper surface of the semiconductor substrate 31. The multi-layer wiring structure includes a plurality of interlayer insulating layers, one or more wiring layers, one or more plugs, and one or more contact plugs. Specifically, interlayer insulating layers 43A, 43B, and 43C are laminated on the upper surface of the semiconductor substrate 31. A contact plug 45A is embedded in the interlayer insulating layer 43A. A wiring 46B and a conductive plug 47B are embedded in the interlayer insulating layer 43B. A wiring 46C and a conductive plug 47C are embedded in the interlayer insulating layer 43C. The power supply through wiring 62 may pass through the plurality of interlayer insulating layers. This results in a multi-layer wiring structure, which can reduce the area occupied by the wiring layers when the substrate is viewed in a plan view, thereby suppressing the enlargement of the element size.

[0163] (Other embodiments) Although the photoelectric conversion device according to one or more aspects has been described based on the embodiments, the present disclosure is not limited to these embodiments. As long as it does not deviate from the gist of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiment and forms constructed by combining components in different embodiments are also included within the scope of the present disclosure.

[0164] For example, the image sensor 101 may detect a change in capacitance of the light detection film 51 without detecting a charge due to photoelectric conversion. Such a type of image sensor and imaging device is disclosed, for example, in Patent Document WO 2017 / 081847. That is, the light detection film 51 may generate hole-electron pairs according to the intensity of the incident light, or the capacitance may change according to the intensity of the incident light. Each pixel 14 can detect the light incident on the light detection film 51 by detecting the generated charge or the change in capacitance.

[0165] Also, for example, the pixel electrodes 50 and the control electrode 60 may be provided in different layers. That is, the height of each of the pixel electrodes 50 from the semiconductor substrate 31 may be different from the height of the control electrode 60 from the semiconductor substrate 31. For example, the control electrode 60 may be provided at a position closer to the semiconductor substrate 31 than the upper surface 43a of the interlayer insulating layer 43. Specifically, the control electrode 60 may be provided between the interlayer insulating layer 43B and the interlayer insulating layer 43C.

[0166] Furthermore, each of the above embodiments can be modified, substituted, added, omitted, and the like in various ways within the scope of the claims or their equivalents. [Industrial Applicability]

[0167] INDUSTRIAL APPLICABILITY The present disclosure can be used as a high-quality, high-performance photoelectric conversion device in which the increase in element size is suppressed, and can be used in, for example, cameras, distance measuring devices, and the like. [Explanation of symbols]

[0168] 10 Light detection section 11 Amplifying transistor 12 Reset transistor 13 Address transistor 14 pixels 15 Vertical scanning circuit 16 Counter electrode signal line 17 Vertical signal line 18 Load circuit 19 Column signal processing circuit 20 Horizontal signal readout circuit 21 Power wiring 22 Differential Amplifier 23 Feedback Line 24 Charge Storage Node 25 Charge detection circuit 26 Address signal line 27 Reset signal line 28 Horizontal common signal line 30 Voltage control circuit 31 Semiconductor Substrate 38A, 38B, 38C Gate insulating layer 39A, 39B, 39C Gate electrode 41A, 41B, 41C, 41D, 41E n-type impurity region 42 Element isolation region 43, 43A, 43B, 43C Interlayer insulation layer 43a, 51b, 52b, 151b, 152b top surface 45A, 45B contact plug 46A, 46B, 46C, 48B, 48C Wiring 47, 47A, 47B, 47C Conductive plug 50, 250 pixel electrodes 51, 151, 251 Photodetector film 51a, 52a, 151a, 152a bottom side 51r Recess 51s, 52s, 53s, 251s side 52 Transparent electrode Areas 52c, 52d, 52e, and 52f 53, 153 Insulating layer 53a Through hole 54 Protective film 55 Color Filter 56 Micro Lens 100 Imaging device 101, 102, 201, 301, 401, 501 Image Sensor 60 Control electrode 60a Part 1 60b 2nd part 61, 461, 561 Connection 62 Power supply through wiring 152 Transparent conductive film 161 Conductive Thin Film 190 Photosensitive resist 191 Resist Pattern 370 Peripheral Circuits 451a, 451b, 451c Laminated structure

Claims

1. A substrate; a light detection film having a first surface facing the substrate and a second surface opposite the first surface; A plurality of first electrodes provided between the substrate and the light detection film; a second electrode provided between the substrate and the light detection film, the second electrode having a first portion overlapping the first surface and a second portion not overlapping the first surface when viewed in a normal direction of the substrate; a third electrode provided on the second surface of the light detection film; A wiring that electrically connects the second electrode and the third electrode; a first conductive plug connected to the first portion of the second electrode and extending toward the substrate; the wiring contacts a side surface of the light detection film and the second portion of the second electrode; The light detection film has a planar shape seen from a normal direction of the substrate, the planar shape having a recess, the second portion of the second electrode overlaps with the recess when viewed from a normal direction of the substrate, the wiring is connected to the second portion of the second electrode in the recess; the first electrode and the second electrode are in contact with the first surface of the light detection film; Photoelectric conversion device.

2. The light detection film further includes a multilayer wiring structure including a plurality of interlayer insulating layers, the multilayer wiring structure being disposed between the substrate and the light detection film; the first conductive plug passes through the plurality of interlayer insulating layers; The photoelectric conversion device according to claim 1 .

3. a material of the wiring has a higher corrosion resistance than the material of the first conductive plug; The photoelectric conversion device according to claim 1 .

4. a plurality of second conductive plugs each in contact with the plurality of first electrodes and extending toward the substrate; a peripheral circuit located between the first conductive plug and the second conductive plug when viewed from a normal direction of the substrate, The photoelectric conversion device according to claim 1 .

5. the entirety of a connection portion of the second electrode with the first conductive plug is included in the first portion; the first conductive plug is connected to a wiring layer disposed between the substrate and the light detection film, or to an electric element provided on the substrate; The photoelectric conversion device according to claim 1 .

6. the third electrode has a third surface facing the second surface and a fourth surface opposite to the third surface, the wiring continuously covers the fourth surface of the third electrode, a side surface of the light detection film, and the second portion of the second electrode; The photoelectric conversion device according to claim 1 .

7. a plurality of stacked structures each including the light detection film and the third electrode; Each of the plurality of laminated structures is laminated on one another in a normal direction of the substrate. The photoelectric conversion device according to claim 1 .

8. Each end of the plurality of laminated structures is provided in a stepped shape. The photoelectric conversion device according to claim 7 .

9. The side surfaces of the plurality of laminated structures are flat across the plurality of laminated structures. The photoelectric conversion device according to claim 7 .

10. The wiring has a film shape. The photoelectric conversion device according to claim 1 .

11. A substrate; a light detection film having a first surface facing the substrate and a second surface opposite the first surface; A plurality of first electrodes provided between the substrate and the light detection film; a second electrode provided between the substrate and the light detection film, the second electrode having a first portion overlapping the first surface and a second portion not overlapping the first surface when viewed in a normal direction of the substrate; a third electrode provided on the second surface of the light detection film; A wiring that electrically connects the second electrode and the third electrode; a first conductive plug connected to the first portion of the second electrode and extending toward the substrate; When viewed from a normal direction of the substrate, the first conductive plug does not overlap the second portion of the second electrode, the wiring continuously covers a side surface of the light detection film and the second portion of the second electrode; Photoelectric conversion device.

12. When viewed in a normal direction of the substrate, the first conductive plug overlaps with the first portion of the second electrode. The photoelectric conversion device according to claim 11 .

13. The light detection film has a planar shape seen from a normal direction of the substrate, the planar shape having a recess, the second portion of the second electrode overlaps with the recess when viewed from a normal direction of the substrate, the wiring is connected to the second portion of the second electrode in the recess; The photoelectric conversion device according to claim 11 or 12.

14. The light detection film includes a photoelectric conversion layer. The photoelectric conversion device according to claim 1 .

15. The light detection film includes a carrier transport layer. The photoelectric conversion device according to claim 1 .

16. The light detection film includes a blocking layer. The photoelectric conversion device according to claim 1 .

17. the material of the first conductive plug is different from the material of the second electrode; The photoelectric conversion device according to claim 1 .

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