Solid-state imaging device and method for manufacturing the same

Abstract

Pixels 8 constituting a solid-state imaging device 1 are provided with: a light-scattering unit 27 for receiving an incident light L1 and producing an absorbed light L2 including scattered light; and a photoelectric conversion unit 26 for receiving the absorbed light L2 from a light input surface 26a and generating a signal voltage corresponding to the received absorbed light L2. The light scattering 27 includes a plurality of metal structures 27a arranged so as to have a predetermined cycle length. The light scattering unit 27 generates, as the scattered light, a diffracted light caused by a plasmon corresponding to the incident light L1.

Description

[Technical Field]

[0001] The present invention relates to a solid-state imaging device and a method for manufacturing the solid-state imaging device. [Background technology]

[0002] A CMOS image sensor includes a photodiode. Each pixel of a CMOS image sensor may include a photodiode. In the technical field of CMOS image sensors, efforts to increase the sensitivity of CMOS image sensors have been underway. In recent years, the use of light in the near-infrared region (wavelengths between 800 nm and 1100 nm) has become increasingly common in the fields of photodiodes and CMOS image sensors. Therefore, increasing sensitivity in the near-infrared region has attracted attention. For example, when using image sensors in surveillance technology, sensitivity can be improved by combining light in the near-infrared region (hereinafter also referred to as "near-infrared light") with visible light. Near-infrared light cannot be detected by the human eye. Therefore, it can be used for hospital room surveillance, gesture input using time-of-flight (ToF), and distance measurement. Therefore, image sensors that detect near-infrared light have a wide range of applications. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-108062 [Patent Document 2] International Publication No. 2018 / 079296 [Patent Document 3] International Publication No. 2018 / 030213 [Patent Document 4] Japanese Patent Application Publication No. 2020-13909 [Non-patent literature]

[0004] [Non-Patent Document 1] Oshiyama Itaru, Yokokawa Sozo, Ikeda Harumi, Ubako Yoshiki, Hirano Tomoyuki, Oinoue Subaru, Saito Taku, Hagimoto Kenya, Iwamoto Hayato, "Improving Infrared Sensitivity of Back-Illuminated CMOS Image Sensors Using PSD Structure," ITE Technical Report, Vol. 41, No. 10, ITE, March 2018. Summary of the Invention [Problem to be solved by the invention]

[0005] Image sensors may be made of silicon. Figure 28 is a graph showing the optical characteristics of silicon. The horizontal axis represents the wavelength of light. The vertical axis represents the wavelength of light absorbed. In the following explanation, the wavelength of light absorbed is referred to as the "absorption length." Referring to graph G28 showing the absorption characteristics, it can be seen that the absorption length increases rapidly from visible light to the near-infrared region. Therefore, in order to detect near-infrared light, it is necessary to increase the thickness of the light absorption region made of silicon.

[0006] Another optical characteristic of silicon is the attenuation of light intensity caused by light absorption. Figure 29 is a graph showing the attenuation of light intensity. The horizontal axis represents the distance traveled by light inside the silicon, in other words, the depth inside the silicon. The vertical axis represents light intensity. Graphs G29a to G29b show the attenuation of light intensity caused by light absorption. fGraph G29a shows the characteristics for each wavelength of light. Graph G29b shows the characteristics for a wavelength of light of 800 nm. Graph G29b shows the characteristics for a wavelength of light of 850 nm. Graph G29c shows the characteristics for a wavelength of light of 900 nm. Graph G29d shows the characteristics for a wavelength of light of 950 nm. Graph G29e shows the characteristics for a wavelength of light of 1000 nm. Graph G29f shows the characteristics for a wavelength of light of 1050 nm. For example, an image sensor for gesture input detects light with a wavelength of 850 nm. Referring to graph G29b, it can be seen that an absorption length of 12 μm is required to absorb half of the light with a wavelength of 850 nm. As another example, an image sensor intended for automotive use detects light with a wavelength of 950 nm. Referring to graph G29d, it can be seen that an absorption length of 44 μm is required to absorb half of the light with a wavelength of 950 nm. μ It can be seen that an absorption length of m is required. The greater the required light absorption rate, the longer the absorption length of the silicon that makes up the light absorbing portion.

[0007] However, the sensor thickness of commonly used visible light image sensors is about 3 μm. The pixel size of surveillance image sensors is also about 3 μm. Considering the dimensions of these image sensors, the absorption length of silicon mentioned above must be said to be long. Therefore, when using silicon to detect near-infrared light, the thickness of silicon required for detection is an issue in the design and manufacturing of the image sensor.

[0008] Therefore, for example, Patent Document 1 and Non-Patent Document 1 disclose technologies aimed at solving the above-mentioned problems. The sensors in Patent Document 1 and Non-Patent Document 1 include a light scattering section that employs a pyramidal structure on the light incident surface. The direction of light incident on the sensor is changed by the light scattering section. Specifically, the direction of light is changed to a direction inclined with respect to the thickness direction of the silicon layer. By changing the direction of light, the distance contributing to light absorption can be substantially extended without increasing the thickness of the silicon layer.

[0009] The light absorbing portion made of silicon may include an isolation wall portion. The isolation wall suppresses crosstalk between pixels. It is also being considered to further extend the distance over which light is absorbed by providing the isolation wall with a light reflecting function.

[0010] For example, Patent Document 1 discloses a technology related to a deep trench insulator (hereinafter also referred to as "DTI"). TI In the example, metals such as tungsten (W) and aluminum (Al) are embedded in trenches by a CVD method. stomach However, optical components such as color filters and microlenses are placed on the negative charge holding film. The optical components are responsible for colorization and light collection. The DTI does not transmit light. As a result, light traveling obliquely due to the light scattering portion does not transmit to adjacent pixels. The DTI suppresses crosstalk by preventing the diffusion of signal electrons to adjacent pixels. The DTI reflects light. As a result, the distance contributing to light absorption in silicon can be substantially extended. This can therefore improve sensitivity.

[0011] For example, Patent Document 2 discloses an element structure having a light scattering portion and a trench (see FIGS. 25 and 28 of Patent Document 2). Patent Document 2 exemplifies several materials to be filled in the trench. The material filled in the trench forms a core. Patent Document 2 exemplifies tungsten, tantalum, copper, aluminum, silver, etc. These metal materials are effective in emitting visible light and near-infrared light. outside lineIt does not transmit light. Patent Document 2 discloses a structure in which a core is thinly covered with a dielectric primarily composed of silicon oxide or silicon nitride. Patent Document 2 demonstrates the advantages of using silicon as a core by calculating the interference of a multilayer film when the core is made of silicon. Patent Document 2 also points out the effect of reduced sensitivity due to a structure including a dielectric. In a structure including a dielectric, the physical properties of the metal that makes up the core absorb part of the visible light and near-infrared light, resulting in a corresponding decrease in sensitivity. Patent Document 2 is negative about using metal materials as materials to be filled into the trench. Patent Document 2 also lists examples of materials to be filled into the trench, such as amorphous silicon, polysilicon, or materials primarily composed of single-crystal silicon.

[0012] Patent Document 3 discloses a solid-state imaging device using a structural color filter. The solid-state imaging device of Patent Document 3 prevents light diffracted inside the light-receiving element 101 that constitutes the unit pixel 103 from transmitting to an adjacent pixel 103. As a result, crosstalk between adjacent pixels is prevented. However, the structural color filter does not function as a light scattering section. The structural color filter functions as a light filter. In this case, it is desirable that the scattering caused by the structural color filter is small. The solid-state imaging device of Patent Document 3 has a metal trench structure. Patent Document 3 lists at least one metal selected from the group consisting of tungsten, titanium, copper, aluminum, and alloys thereof as an example of the material for the metal trench structure.

[0013] In the technical field of imaging elements, there is a demand for an image sensor having a photoelectric conversion efficiency of near-infrared light that is even higher than that of the image sensor employing the above-described configuration. The present invention provides a solid-state imaging device and a method for manufacturing a solid-state imaging device that can further improve the photoelectric conversion efficiency of near-infrared light. [Means for solving the problem]

[0014] A first aspect of the present invention is a solid-state imaging device including a plurality of pixels. Each pixel includes a light scattering section that receives incident light and generates absorbed light including scattered light, and a photoelectric conversion section that receives the absorbed light from a light input surface and generates a signal voltage corresponding to the absorbed light. The light scattering section includes a plurality of metal structures arranged with a predetermined periodic length, and generates, as scattered light, diffracted light due to plasmons in response to the incident light.

[0015] The solid-state imaging device diffracts incident light using a light scattering section including a plurality of metal structures. The diffraction of light by the light scattering section including a plurality of metal structures is caused by the plasmon phenomenon. The generation of diffracted light can be controlled by the periodic length that defines the arrangement of the plurality of metal structures. Therefore, a desired scattering angle can be obtained, and an optical path length determined by the wavelength of the incident light and the light absorption characteristics of the photoelectric conversion section can be ensured. As a result, the photoelectric conversion efficiency of near-infrared light can be further improved.

[0016] In the solid-state imaging device of the first embodiment, the periodic length of the plurality of metal structures may be a variable P. The real part of the refractive index of the photoelectric conversion section may be a variable n. The wavelength of the incident light may be a variable λ. The variable l may be 1 or 2. The variables P, n, λ, and l may satisfy formula (1).

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[0017] This configuration reduces the proportion of zero-order diffracted light that travels straight in the thickness direction of the photoelectric conversion unit. It also increases the proportion of diffracted light of orders that travel obliquely relative to the thickness direction of the photoelectric conversion unit. As a result, the amount of diffracted light in the photoelectric conversion unit can be set to a desired level. Furthermore, the distance contributing to light absorption can also be set to a desired level. This further increases the photoelectric conversion efficiency of near-infrared light.

[0018] The plurality of metal structures in the solid-state imaging device of the first embodiment may form a first periodic structure along a first direction and a second periodic structure along a second direction intersecting the first direction. With this configuration, the mode of incident light or the mode of diffraction targeted by the first periodic structure can be made different from the mode of incident light or the mode of diffraction targeted by the second periodic structure.

[0019] In the solid-state imaging device of the first embodiment, the periodic length of the first periodic structure may be different from the periodic length of the second periodic structure. This configuration also makes it possible to make the mode of incident light or diffraction target by the first periodic structure different from the mode of incident light or diffraction target by the second periodic structure.

[0020] The solid-state imaging device of the first embodiment may further include a charge retention film disposed between the light scattering portion and the photoelectric conversion portion. This configuration also makes it possible to further increase the photoelectric conversion efficiency of near-infrared light and also to suppress dark current.

[0021] A high-concentration impurity layer may be provided on the light input surface of the photoelectric conversion unit in the solid-state imaging device of the first embodiment. This configuration also further improves the photoelectric conversion efficiency of near-infrared light and also suppresses dark current.

[0022] The plurality of metal structures in the solid-state imaging device of the first embodiment may be formed of a material selected from the group consisting of silver, aluminum, gold, copper, and titanium nitride. This configuration makes it possible to obtain a solid-state imaging device including metal structures formed of a material selected from the group consisting of silver, aluminum, gold, copper, and titanium nitride.

[0023] The plurality of metal structures in the solid-state imaging device of the first embodiment may be formed of a material selected from the group consisting of a material containing silver as a main component, a material containing aluminum as a main component, a material containing gold as a main component, a material containing copper as a main component, and a material containing titanium nitride as a main component. This configuration makes it possible to obtain a solid-state imaging device including metal structures formed of a material selected from the group consisting of a material containing silver as a main component, a material containing aluminum as a main component, a material containing gold as a main component, a material containing copper as a main component, and a material containing titanium nitride as a main component.

[0024] The solid-state imaging device of the first embodiment may further include a first isolation wall portion provided between adjacent pixels. The first isolation wall portion may include a trench and a light reflecting portion embedded in the trench. The light reflecting portion may be formed of a material whose real part (n2) and imaginary part (k2) of the refractive index in the wavelength range of incident light from 800 nm to 1100 nm satisfy formula (2). This configuration enables diffracted light to be suitably reflected by the first isolation wall portion. As a result, the photoelectric conversion efficiency of near-infrared light can be further improved.

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[0025] The light reflecting portion in the solid-state imaging device of the first embodiment may be made of a material selected from the group consisting of silver, copper, gold, platinum, and bismuth. These materials satisfy formula (2) at a wavelength of 950 nm. This configuration makes it possible to obtain a solid-state imaging device having a light reflecting portion made of a material selected from the group consisting of silver, copper, gold, platinum, and bismuth.

[0026] The light reflecting portion in the solid-state imaging device of the first embodiment may be formed of a material selected from the group consisting of a material containing silver as a main component, a material containing copper as a main component, a material containing gold as a main component, a material containing platinum as a main component, and a material containing bismuth as a main component. This configuration makes it possible to obtain a solid-state imaging device having a light reflecting portion formed of a material selected from the group consisting of a material containing silver as a main component, a material containing copper as a main component, a material containing gold as a main component, a material containing platinum as a main component, and a material containing bismuth as a main component.

[0027] In the solid-state imaging device of the first embodiment, the trench width may be 45 nm or more, and the light reflecting portion may be made of silver or a material containing silver as a main component. With this configuration, it is possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0028] In the solid-state imaging device of the first embodiment, the trench width may be 50 nm or more. The light reflecting portion may be made of copper or a material containing copper as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0029] In the solid-state imaging device of the first embodiment, the trench width may be 60 nm or more. The light reflecting portion may be made of gold or a material containing gold as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0030] In the solid-state imaging device of the first embodiment, the trench width may be 30 nm or more. The light reflecting portion may be made of platinum or a material containing platinum as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0031] In the solid-state imaging device of the first embodiment, the trench width may be 70 nm or more. The light reflecting portion may be made of bismuth or a material containing bismuth as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0032] The solid-state imaging device of the first embodiment may further include a first isolation wall portion provided between adjacent pixels. The first isolation wall portion may include a trench and a light reflecting portion embedded in the trench. The trench may have a width of 35 nm or more. The light reflecting portion may be made of aluminum or a material containing aluminum as a main component. This configuration also makes it possible to obtain a first isolation wall portion that can suitably reflect diffracted light.

[0033] In the solid-state imaging device of the first embodiment, the first isolation wall may further include a negative charge retention film provided between the wall surface of the trench and the light reflecting portion, which can suppress the generation of dark current at the interface of the trench.

[0034] The negative charge retention film in the solid-state imaging device of the first embodiment may be made of aluminum oxide. This configuration makes it possible to obtain a solid-state imaging device including a negative charge retention film made of aluminum oxide.

[0035] The negative charge retention film in the solid-state imaging device of the first embodiment may be made of silicon nitride. This configuration makes it possible to obtain a solid-state imaging device including a negative charge retention film made of silicon nitride.

[0036] The solid-state imaging device of the first embodiment may further include a first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench, and a second isolation wall portion adjacent to the first isolation wall portion across the photoelectric conversion portion and including a trench and a light reflecting portion embedded in the trench. The distance from the light reflecting portion of the first isolation wall portion to the light reflecting portion of the second isolation wall portion may be defined as a variable W PD The periodic length of the plurality of metal structures may be set as a variable P. The number of periods of the plurality of metal structures, i.e., the number of the plurality of metal structures, may be set as a variable M. The width of each of the plurality of metal structures may be set as a variable W. metal The variable W PD , variable P and variable W metalmay satisfy formula (3). The variable j may be 0 or a positive integer. With this configuration, an interference field in which a standing wave exists between the first and second partition walls can be formed. By satisfying formula (3), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further improved.

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[0037] In the solid-state imaging device of the first embodiment, the distance from the plurality of metal structures to the light reflecting portion of the first isolation wall is set to a variable X L and the distance from the plurality of metal structures to the light reflecting portion of the second isolation wall portion is defined as a variable X R Then, the variable X L and variable X R may be equal to each other. This configuration also makes it possible to further increase the degree of interference. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

[0038] The solid-state imaging device of the first embodiment may further include a first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench, and a second isolation wall portion adjacent to the first isolation wall portion across the photoelectric conversion portion and including a trench and a light reflecting portion embedded in the trench. The distance from the light reflecting portion of the first isolation wall portion to the light reflecting portion of the second isolation wall portion may be defined as a variable W PD The periodic length of the plurality of metal structures may be set as variable P. The number of periods of the plurality of metal structures, that is, the number of the plurality of metal structures, may be set as variable M. The variable W PD The variables P and M may satisfy formula (4). The variable j may be 0 or a positive integer. This configuration also makes it possible to form an interference field in which a standing wave exists between the first and second partition walls. By satisfying formula (4), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0039] A solid-state imaging device according to a second embodiment of the present invention includes a plurality of pixels and a first isolation wall portion provided between adjacent pixels. The pixels include a photoelectric conversion portion that receives absorbed light from a light input surface and generates a signal voltage corresponding to the received absorbed light. The first isolation wall portion includes a trench and a light reflecting portion embedded in the trench. The light reflecting portion is formed of a material whose real part (n2) and imaginary part (k2) of the refractive index satisfy formula (5) in the wavelength range of 800 nm to 1100 nm of incident light entering the pixel. This configuration enables diffracted light to be suitably reflected by the first isolation wall portion. As a result, the photoelectric conversion efficiency of near-infrared light can be further improved.

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[0040] The light reflecting portion in the solid-state imaging device of the second embodiment may be made of a material selected from the group consisting of silver, copper, gold, platinum, and bismuth. This configuration makes it possible to obtain a solid-state imaging device having a light reflecting portion made of a material selected from the group consisting of silver, copper, gold, platinum, and bismuth.

[0041] The light reflecting portion in the solid-state imaging device of the second embodiment may be formed of a material selected from the group consisting of a material containing silver as a main component, a material containing copper as a main component, a material containing gold as a main component, a material containing platinum as a main component, and a material containing bismuth as a main component. This configuration makes it possible to obtain a solid-state imaging device having a light reflecting portion formed of a material selected from the group consisting of a material containing silver as a main component, a material containing copper as a main component, a material containing gold as a main component, a material containing platinum as a main component, and a material containing bismuth as a main component.

[0042] In the solid-state imaging device of the second embodiment, the trench width may be 45 nm or more. The light reflecting portion may be made of silver or a material containing silver as a main component. This configuration makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0043] In the solid-state imaging device of the second embodiment, the trench width may be 50 nm or more. The light reflecting portion may be made of copper or a material containing copper as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0044] In the solid-state imaging device of the second embodiment, the trench width may be 60 nm or more. The light reflecting portion may be made of gold or a material containing gold as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0045] In the solid-state imaging device of the second embodiment, the trench width may be 30 nm or more. The light reflecting portion may be made of platinum or a material containing platinum as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0046] In the solid-state imaging device of the second embodiment, the trench width may be 70 nm or more. The light reflecting portion may be made of bismuth or a material containing bismuth as a main component. This configuration also makes it possible to obtain a first isolating wall portion that can suitably reflect diffracted light.

[0047] In the solid-state imaging device of the second embodiment, the first isolation wall may further include a negative charge retention film provided between the wall surface of the trench and the light reflecting portion, which can suppress the generation of dark current at the interface of the trench.

[0048] The negative charge retention film in the solid-state imaging device of the second embodiment may be made of aluminum oxide. This configuration makes it possible to obtain a solid-state imaging device including a negative charge retention film made of aluminum oxide.

[0049] The negative charge retention film in the solid-state imaging device of the second embodiment may be made of silicon nitride. This configuration makes it possible to obtain a solid-state imaging device including a negative charge retention film made of silicon nitride.

[0050] The solid-state imaging device of the second embodiment may further include a light scattering section that receives incident light and generates absorbed light including scattered light, and a second isolating wall section that is adjacent to the first isolating wall section with the photoelectric conversion section sandwiched therebetween. The light scattering section may include a plurality of metal structures that are arranged with a predetermined periodic length. The distance from the light reflecting section of the first isolating wall section to the light reflecting section of the second isolating wall section may be defined as a variable W PD The periodic length of the plurality of metal structures may be set as a variable P. The number of periods of the plurality of metal structures, that is, the number of the plurality of metal structures, may be set as a variable M. The width of each of the plurality of metal structures may be set as a variable W. metal The variable W PD , variable P and variable W metal may satisfy formula (6). The variable j may be 0 or a positive integer. With this configuration, an interference field in which a standing wave exists between the first and second partition walls can be formed. By satisfying formula (6), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0051] In the solid-state imaging device of the second embodiment, the distance from the plurality of metal structures to the light reflecting portion of the first isolation wall is set to a variable X L and the distance from the plurality of metal structures to the light reflecting portion of the second isolation wall portion is defined as a variable X R Then, the variable X L and variable X R may be equal to each other. This configuration also makes it possible to further increase the degree of interference. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

[0052] The solid-state imaging device of the second embodiment may further include a light scattering section that receives incident light and generates absorbed light including scattered light, and a second isolating wall section that is adjacent to the first isolating wall section with the photoelectric conversion section interposed therebetween. The light scattering section may include a plurality of metal structures that are arranged with a predetermined periodic length. The distance from the first isolating wall section to the second isolating wall section may be defined as a variable W PD The periodic length of the plurality of metal structures may be set as variable P. The number of periods of the plurality of metal structures, that is, the number of the plurality of metal structures, may be set as variable M. The variable W PD The variables P and M may satisfy formula (7). The variable j may be 0 or a positive integer. This configuration also makes it possible to form an interference field in which a standing wave exists between the first and second partition walls. By satisfying formula (7), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0053] The solid-state imaging device of the second embodiment may further include a light scattering section that receives incident light and generates absorbed light including scattered light, and a second isolating wall section that is adjacent to the first isolating wall section with the photoelectric conversion section interposed therebetween. PD The real part of the refractive index of the photoelectric conversion unit may be expressed as a variable n Si The wave number of the incident light may be set as a variable k0. The angle of diffraction of the incident light caused by the light scattering portion may be set as a variable θ d The variable m may be a natural number. The variable W PD , variable n Si , variable k0, variable θ d , and the variable m may satisfy formula (8). This configuration also makes it possible to form an interference field in which a standing wave exists between the first and second isolating walls. By satisfying formula (8), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0054] A solid-state imaging device according to a third aspect of the present invention includes a plurality of pixels and a first isolation wall portion provided between adjacent pixels. The pixels include a photoelectric conversion portion that receives absorbed light from a light input surface and generates a signal voltage corresponding to the received absorbed light. The first isolation wall portion includes a trench and a light reflecting portion embedded in the trench. The trench has a width of 35 nm or more. The light reflecting portion is formed of aluminum or a material containing aluminum as a main component. This configuration also makes it possible to obtain a first isolation wall portion that can favorably reflect diffracted light.

[0055] The solid-state imaging device of the third embodiment may further include a light scattering section that receives incident light and generates absorbed light including scattered light, and a second isolating wall section that is adjacent to the first isolating wall section with the photoelectric conversion section sandwiched therebetween. The light scattering section may include a plurality of metal structures arranged with a predetermined periodic length. The distance from the light reflecting section of the first isolating wall section to the light reflecting section of the second isolating wall section may be defined as a variable W. PD The periodic length of the plurality of metal structures may be set as a variable P. The number of periods of the plurality of metal structures, that is, the number of the plurality of metal structures, may be set as a variable M. The width of each of the plurality of metal structures may be set as a variable W. metal The variable W PD , variable P and variable W metal may satisfy equation (9). The variable j may be 0 or a positive integer. This configuration also makes it possible to form an interference field in which a standing wave exists between the first and second isolating walls. By satisfying equation (9), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0056] The solid-state imaging device of the third embodiment may further include a light scattering section that receives incident light and generates absorbed light including scattered light, and a second isolating wall section that is adjacent to the first isolating wall section with the photoelectric conversion section interposed therebetween. PD The real part of the refractive index of the photoelectric conversion unit may be expressed as a variable n Si The wave number of the incident light may be set as a variable k0. The angle of diffraction of the incident light caused by the light scattering portion may be set as a variable θ d The variable m may be a natural number. The variable W PD , variable n Si , variable k0, variable θ d , and the variable m may satisfy formula (10). This configuration also makes it possible to form an interference field in which a standing wave exists between the first and second isolating walls. By satisfying formula (10), the degree of interference can be strengthened. As a result, the photoelectric conversion efficiency of near-infrared light can be further increased.

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[0057] A fourth aspect of the present invention is a method for manufacturing a solid-state imaging device having a plurality of pixels and a first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench. The method for manufacturing the solid-state imaging device includes the steps of forming a trench and forming the light reflecting portion in the trench. In the step of forming the light reflecting portion, a material whose real part (n2) of the refractive index and imaginary part (k2) of the refractive index satisfy Equation (11) in the wavelength range of incident light from 800 nm to 1100 nm is provided in the trench by atomic layer deposition.

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[0058] According to the method for manufacturing a solid-state imaging device, it is possible to form a first isolating wall portion that effectively reflects diffracted light, thereby manufacturing a solid-state imaging device with improved photoelectric conversion efficiency for near-infrared light.

[0059] In the method for manufacturing a solid-state imaging device according to the fourth aspect, the light reflecting portion may be formed by atomic layer deposition using a source gas containing silver. The source gas containing silver may be triethylphosphine(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)silver(I). This method allows the formation of a light reflecting portion made of silver.

[0060] The fourth form In a state In a method for manufacturing a solid-state imaging device, in the step of forming a light-reflecting portion, the light-reflecting portion may be formed by atomic layer deposition using a source gas containing copper. The source gas containing copper may be bis(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) or bis(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)copper(II). This method allows the formation of a light-reflecting portion made of copper.

[0061] In the method for manufacturing a solid-state imaging device according to the fourth aspect, in the step of forming the light reflecting portion, the light reflecting portion may be formed by atomic layer deposition using a source gas containing gold. The source gas containing gold may be trimethyl(trimethylphosphine)gold(III). This method allows the formation of a light reflecting portion made of gold.

[0062] In the method for manufacturing a solid-state imaging device according to the fourth aspect, in the step of forming the light reflecting portion, the light reflecting portion may be formed by atomic layer deposition using a source gas containing aluminum. The source gas containing aluminum may be trimethyl aluminum, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)aluminum, or triethyl aluminum. This method allows the formation of a light reflecting portion made of aluminum.

[0063] In the method for manufacturing a solid-state imaging device according to the fourth aspect, in the step of forming the light-reflecting portion, the light-reflecting portion may be formed by atomic layer deposition using a source gas containing bismuth. The source gas containing bismuth may be a material selected from the group consisting of triphenylbismuth, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)bismuth, bis(acetato-O)triphenylbismuth, tris(2-methoxyphenyl)bismuthine, tri(tert-butyloxy)bismuth, tris(1,1,2-trimethylpropyloxy)bismuth, and tris(1,1-diisopropyl-2-methylpropyloxy)bismuth. This method allows the formation of a light-reflecting portion made of bismuth.

[0064] In the method for manufacturing a solid-state imaging device according to the fourth aspect, in the step of forming the light reflecting portion, the light reflecting portion may be formed by atomic layer deposition using a source gas containing platinum. The source gas containing platinum may be (trimethyl)methylcyclopentadienyl platinum(IV). This method allows the formation of a light reflecting portion made of platinum.

[0065] The photoelectric conversion unit included in the solid-state imaging device may include a photoelectric conversion main surface including a light input surface and a photoelectric conversion rear surface opposite to the photoelectric conversion main surface. A light direction changing unit that changes the traveling direction of the absorbed light may be provided on the photoelectric conversion rear surface. The light direction changing unit may change the traveling direction of the absorbed light so that the angle of the absorbed light with respect to the reference axis after the traveling direction has been changed is different from the angle of the absorbed light with respect to the reference axis before the traveling direction has been changed.

[0066] A solid-state imaging device according to a fifth aspect of the present invention includes a plurality of pixels, each including a photoelectric conversion unit that generates a signal voltage in response to absorbed light, and an isolation wall portion provided between adjacent pixels, each including a trench and a light reflecting portion embedded in the trench. The photoelectric conversion unit includes a photoelectric conversion main surface including a light input surface that receives incident light, and a photoelectric conversion back surface opposite to the photoelectric conversion main surface. A light direction changing unit is provided on the photoelectric conversion back surface. The light direction changing unit changes the traveling direction of the absorbed light so that the angle of the absorbed light relative to a reference axis after the traveling direction has been changed is different from the angle of the absorbed light relative to the reference axis before the traveling direction has been changed.

[0067] In the solid-state imaging device, a normal to the light input surface of the absorbed light after the propagation direction has been changed may be set as a reference axis, and an angle relative to the reference axis may correspond to an angle relative to the normal to the light input surface of the absorbed light before the propagation direction has been changed, where the angle is an absolute value of the angle relative to the reference axis.

[0068] In the above solid-state imaging device, the light direction changing portion may be inclined with respect to a reference axis based on the normal line, and may reflect the received light.

[0069] In the above solid-state imaging device, a wiring portion may be in contact with the rear surface of the photoelectric conversion portion.

[0070] In the solid-state imaging device, the light direction changing portion may include a reflecting portion provided on the wiring portion.

[0071] In the above solid-state imaging device, the light redirection portion may include at least one light redirection body that protrudes from the photoelectric conversion rear surface or that is recessed from the photoelectric conversion rear surface.

[0072] In the above-mentioned solid-state imaging device, the height of the light direction changer that protrudes from the back surface of the photoelectric conversion element or the depth of the light direction changer that is recessed from the back surface of the photoelectric conversion element corresponds to the wavelength of the absorbed light based on the refractive index of the photoelectric conversion element.

[0073] In the solid-state imaging device, the height of the light redirector from the rear surface of the photoelectric conversion element may be greater than 1 / 10 of the wavelength of light to be absorbed based on the refractive index of the photoelectric conversion element.

[0074] In the solid-state imaging device, the height of the light redirector from the rear surface of the photoelectric conversion element may be smaller than five times the wavelength of light to be absorbed based on the refractive index of the photoelectric conversion element.

[0075] In the solid-state imaging device, the light redirector may include a surface that is flat.

[0076] In the above solid-state imaging device, the cross-sectional shape of the light redirector may include a rectangular portion.

[0077] In the solid-state imaging device, the light redirector may have a rectangular parallelepiped shape made up of flat surfaces.

[0078] In the solid-state imaging device, the cross-sectional shape of the light redirector may be triangular.

[0079] In the solid-state imaging device, the light redirector may have a quadrangular pyramid shape formed by flat surfaces.

[0080] In the above solid-state imaging device, the light redirector may have a triangular prism shape formed by flat surfaces.

[0081] In the solid-state imaging device, the light redirector may include a surface that is a curved surface.

[0082] In the above solid-state imaging device, the cross-sectional shape of the light redirector may include a portion that is elliptical.

[0083] In the above solid-state imaging device, the light redirection body may have a shape that is a body of revolution obtained by rotating a cross section including an elliptical portion around an axis.

[0084] In the solid-state imaging device, the light redirecting body may have a shape of a sweep body having a cross section including an elliptical portion stretched along an axis.

[0085] In the above solid-state imaging device, the light direction changing section may be configured in a grid shape when viewed in a plane by arranging a plurality of light direction changing bodies along a first direction and a second direction intersecting the first direction.

[0086] In the above solid-state imaging device, the light direction changer may be configured in a striped pattern in a planar view by the light direction changer extending along a first direction and arranging multiple light direction changers along a second direction that intersects the first direction.

[0087] The photoelectric conversion unit of the solid-state imaging device may include a first photoelectric conversion interface including a light input surface, and a second photoelectric conversion interface that is an interface different from the first photoelectric conversion interface and changes the traveling direction of absorbed light received from the light input surface. The absorbed light may travel from the light input surface into the photoelectric conversion unit at a first angle. The absorbed light, whose traveling direction has been changed at the second photoelectric conversion interface, may be incident on the light input surface at a second angle. The second photoelectric conversion interface may change the traveling direction of the absorbed light so that the second angle is different from the first angle.

[0088] In the photoelectric conversion section of the solid-state imaging device, the second photoelectric conversion interface may be a boundary surface with a wiring section provided on a rear surface of the photoelectric conversion section opposite to the first photoelectric conversion interface.

[0089] The second photoelectric conversion interface may be a boundary surface with a trench provided so as to intersect with the first photoelectric conversion interface. [Effects of the Invention]

[0090] According to the present invention, a solid-state imaging device capable of further improving the photoelectric conversion efficiency of near-infrared light and a method for manufacturing the solid-state imaging device are provided. [Brief explanation of the drawings]

[0091] [Figure 1] FIG. 1 is a diagram schematically showing the configuration of a solid-state imaging device according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the electrical configuration of a pixel. [Figure 3] FIG. 3 is an example of the control signals provided to the pixels. [Figure 4] FIG. 4 is a diagram showing the structure of a pixel. [Figure 5] FIG. 5 is an enlarged view of a portion of FIG. 4, in the vicinity of the light input surface (S1). [Figure 6] FIG. 6 is a diagram showing the outline of the operation of the light scattering portion and the DTI. [Figure 7] FIG. 7 is a diagram showing the workings of DTI. [Figure 8] FIG. 8 is a graph showing the reflectance when light is perpendicularly incident from the first member to the second member. [Figure 9] FIG. 9 is a diagram showing a schematic diagram of how light is attenuated each time it is reflected in the DTI. [Figure 10] FIG. 10 is a graph showing the relationship between the number of reflections and the effective magnification. [Figure 11] FIG. 11 is a graph showing the relationship between reflectance and effective magnification when the number of reflections is infinite. [Figure 12] FIG. 12 is a table summarizing the refractive indices of various materials. [Figure 13] FIG. 13 is a graph showing the relationship between the real part of the refractive index and the imaginary part of the refractive index of the buried material. [Figure 14] FIG. 14 is a table summarizing the complex refractive index, reference source, reflectance relative to silicon, real part of dielectric constant, and imaginary part of dielectric constant of various materials. [Figure 15] Figure 15(a) is a schematic diagram of the analytical model used for the study, Figure 15(b) is a graph showing the relationship between film thickness and reflectance, and Figure 15(c) is a graph showing the relationship between film thickness and transmittance. [Figure 16] FIG. 16 is a diagram showing various parameters used in the calculation to obtain the optimum width. [Figure 17]17(a), 17(b), 17(c), and 17(d) are diagrams showing the main steps of a method for manufacturing a solid-state imaging device. [Figure 18] FIG. 18 is a diagram showing a light scattering section included in a solid-state imaging device according to a modified example. [Figure 19] FIG. 19 is a diagram showing a solid-state imaging device including a negative charge holding film. [Figure 20] Fig. 20(a) is a diagram showing a pyramidal light scattering portion, and Fig. 20(b) is a diagram showing a randomly asperity-shaped light scattering portion. [Figure 21] Fig. 21(a) is a diagram showing the model used in the first study, and Fig. 21(b) is a graph showing the results of the first study. [Figure 22] 22(a), 22(b), 22(c) and 22(d) are diagrams that schematically show the conditions used in the second study. [Figure 23] 23(a), 23(b), 23(c) and 23(d) are diagrams schematically showing the conditions used in the second study. [Figure 24] Figure 24(a) is a diagram showing the conditions used in the second study, and Figure 24(b) is a graph showing the results of the second study. [Figure 25] Figure 25(a) is a contour diagram showing the results of a simulation of a diffraction mode using plasmons in a solid-state imaging device without a DTI, and Figure 25(b) is a pie chart showing the results of a simulation of a diffraction mode using plasmons in a solid-state imaging device without a DTI. [Figure 26] Figure 26(a) is a contour diagram showing the results of a simulation of a diffraction mode using plasmons in a solid-state imaging device with a DTI, and Figure 26(b) is a pie chart showing the results of a simulation of a diffraction mode using plasmons in a solid-state imaging device with a DTI. [Figure 27] FIG. 27 is a graph showing the relationship between silicon thickness and cumulative absorption amount. [Figure 28] FIG. 28 is a graph showing the optical characteristics of silicon. [Figure 29]FIG. 29 is a graph showing the attenuation of light intensity. [Figure 30] Fig. 30(a) is a contour diagram showing the distribution of electric field intensity, which is the result of the fifth study. Fig. 30(b) is a table summarizing the results of the fifth, sixth, seventh, and eighth studies. [Figure 31] FIG. 31 is a diagram simply illustrating the analytical model used in the fifth study. [Figure 32] Fig. 32(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Embodiment 2. Fig. 32(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 33] FIG. 33 is a diagram schematically showing how light travels inside the photoelectric conversion layer of the solid-state imaging device 11 of the second embodiment. [Figure 34] FIG. 34 is a contour diagram showing the distribution of the electric field intensity, which is the result of the sixth study. [Figure 35] Fig. 35(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 1 of Embodiment 2. Fig. 35(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 36] Fig. 36(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 2 of Embodiment 2. Fig. 36(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 37] Fig. 37(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 3 of Embodiment 2. Fig. 37(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 38] Fig. 38(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 4 of Embodiment 2. Fig. 38(b) is a perspective view showing the interface of a photoelectric conversion layer included in the solid-state imaging device on the wiring layer side. [Figure 39] Fig. 39(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 5 of Embodiment 2. Fig. 39(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 40]Fig. 40(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 6 of Embodiment 2. Fig. 40(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 41] Fig. 41(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 7 of Embodiment 2. Fig. 41(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 42] Fig. 42(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Embodiment 3. Fig. 42(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 43] FIG. 43 is a diagram schematically showing how light travels inside the photoelectric conversion layer 409 of the solid-state imaging device 19 according to the third embodiment. [Figure 44] Fig. 44(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 1 of Embodiment 3. Fig. 44(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 45] Fig. 45(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 2 of Embodiment 3. Fig. 45(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 46] Fig. 46(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 3 of Embodiment 3. Fig. 46(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 47] Fig. 47(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 4 of Embodiment 3. Fig. 47(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 48] Fig. 48(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 5 of Embodiment 3. Fig. 48(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 49] Fig. 49(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 6 of Embodiment 3. Fig. 49(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 50] Fig. 50(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 7 of Embodiment 3. Fig. 50(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 51] Fig. 51(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 8 of Embodiment 3. Fig. 51(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 52] Fig. 52(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 9 of Embodiment 3. Fig. 52(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 53] Fig. 53(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 10 of Embodiment 3. Fig. 53(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 54] Fig. 54(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 11 of Embodiment 3. Fig. 54(b) is a perspective view showing the interface of a photoelectric conversion layer included in the solid-state imaging device on the wiring layer side. [Figure 55] Fig. 55(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 12 of Embodiment 3. Fig. 55(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 56] Fig. 56(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 13 of Embodiment 3. Fig. 56(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 57] Fig. 57(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 14 of Embodiment 3. Fig. 57(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 58] Fig. 58(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 15 of Embodiment 3. Fig. 58(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 59]Fig. 59(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 16 of Embodiment 3. Fig. 59(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 60] Fig. 60(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 17 of Embodiment 3. Fig. 60(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 61] Fig. 61(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 18 of Embodiment 3. Fig. 61(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 62] Fig. 62(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 19 of Embodiment 3. Fig. 62(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 63] Fig. 63(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 20 of Embodiment 3. Fig. 63(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 64] Fig. 64(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 21 of Embodiment 3. Fig. 64(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 65] Fig. 65(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 22 of Embodiment 3. Fig. 65(b) is a perspective view showing a photoelectric conversion layer wiring layer side interface 4 included in the solid-state imaging device. [Figure 66] Fig. 66(a) is a cross-sectional view showing the structure of a solid-state imaging device according to Modification 23 of Embodiment 3. Fig. 66(b) is a perspective view showing the interface of a photoelectric conversion layer provided in the solid-state imaging device on the wiring layer side. [Figure 67] 67(a), 67(b), 67(c), and 67(d) are cross-sectional views showing further modifications of the solid-state imaging devices of the second embodiment and the modification of the second embodiment. [Figure 68]68(a), 68(b), 68(c), 68(d), 68(e), and 68(f) are cross-sectional views showing further modified examples of the solid-state imaging device of the third embodiment. [Figure 69] 69(a), 69(b), 69(c), 69(d), 69(e), and 69(f) are cross-sectional views showing further modified examples of the solid-state imaging device of the third embodiment. [Figure 70] Figure 70(a) is a cross-sectional view showing a further modified example of the solid-state imaging device of the third embodiment, and Figure 70(b) is a cross-sectional view showing the structure of the solid-state imaging device of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0092] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0093] The following description relates to increasing the sensitivity of a photodiode or a CMOS image sensor in which each pixel is equipped with a photodiode, and in particular to increasing the sensitivity in the near-infrared light region.

[0094] As shown in FIG. 1, the solid-state imaging device 1 of this embodiment is a so-called back-illuminated image sensor. The solid-state imaging device 1 may receive light from the opposite side. The opposite side refers to the side of a support substrate 11, which will be described later. The solid-state imaging device 1 includes a pixel section 2, a pixel control unit 3, a signal processing unit 4, a plurality of horizontal control lines 6, and a plurality of vertical signal lines 7. The pixel section 2, pixel control unit 3, and signal processing unit 4 are provided on a sensor substrate 12, which will be described later. The sensor substrate 12 is bonded to a support substrate 11. The sensor substrate 12, which is a silicon wafer on which the pixel section 2 is formed, is thin. Therefore, the sensor substrate 12 lacks mechanical strength. The support substrate 11 provides the solid-state imaging device 1 with mechanical strength. The pixel section 2 is provided in a portion of the sensor substrate 12 corresponding to the light-receiving region S. The pixel section 2 includes a plurality of pixels 8 arranged two-dimensionally. The pixels 8 output signal voltages corresponding to incident light to the vertical signal lines 7. The pixel control unit 3 is connected to each pixel 8 via the horizontal control lines 6. The pixel control unit 3 outputs a control signal φ for controlling the operation of the pixels 8. The signal processing unit 4 is connected to each pixel 8 via a vertical signal line 7. The signal processing unit 4 receives a signal voltage Δ output by the pixel 8. The signal processing unit 4 generates an image signal from the signal voltage Δ output from the pixel 8.

[0095] FIG. 2 is a diagram showing the electrical configuration of pixel 8. Pixel 8 is a so-called four-transistor CMOS image sensor. Pixel 8 in this embodiment is an N-channel type. Signals from pixel 8 are carried by signal electrons. Note that pixel 8 may also be a P-channel type.

[0096] The pixel 8 includes a photodiode PD, a floating diffusion layer FD, a transfer gate TG, a reset transistor RG, a source follower transistor SF, and a selection transistor SEL.

[0097] The photodiode PD is a PN junction type. The photodiode PD generates signal electrons as carriers and accumulates the generated signal electrons.

[0098] The transfer gate TG, the reset transistor RG, the source follower transistor SF, and the selection transistor SEL are each a field effect transistor.

[0099] The source of the transfer gate TG is connected to the photodiode PD. The drain of the transfer gate TG is connected to the floating diffusion layer FD. The gate of the transfer gate TG is connected to a horizontal control line 6. The transfer gate TG receives a control signal φ1 from the horizontal control line 6. The transfer gate TG controls the transfer of signal electrons from the photodiode PD to the floating diffusion layer FD based on the control signal φ1.

[0100] The floating diffusion layer FD is connected to the drain of the transfer gate TG. In other words, the floating diffusion layer FD is connected to the photodiode PD via the transfer gate TG. The floating diffusion layer FD converts signal electrons into a signal voltage. The floating diffusion layer FD is connected to the source of the reset transistor RG. The floating diffusion layer FD is also connected to the gate of the source follower transistor SF.

[0101] The source of the reset transistor RG is connected to the floating diffusion layer FD. The drain of the reset transistor RG is connected to the reset drain. The gate of the reset transistor RG is connected to a horizontal control line 6. The reset transistor RG receives a control signal φ2 from the horizontal control line 6. The reset transistor RG resets the potential of the floating diffusion layer FD based on the control signal φ2.

[0102] The source of the source follower transistor SF is connected to the selection transistor SEL. The drain of the source follower transistor SF is connected to an analog power supply. The gate of the source follower transistor SF is connected to a horizontal control line 6. The source follower transistor SF outputs a signal voltage corresponding to the voltage input to the gate of the selection transistor SEL.

[0103] The source of the selection transistor SEL is connected to the vertical signal line 7. The drain of the selection transistor SEL is connected to the source of the source follower transistor SF. The gate of the selection transistor SEL is connected to the horizontal control line 6. The selection transistor SEL outputs a signal voltage Δ to the vertical signal line 7 based on a control signal φ3.

[0104] 3 is a diagram showing the control signals φ1, φ2, φ3, RS, and SS output by the pixel control unit 3. FIG. 3 shows the timing of the control signals φ1, φ2, φ3, RS, and SS during the readout period of the nth row. In the following explanation, "(H)" indicates that the signal is high, that is, on. "(L)" indicates that the signal is low, that is, off.

[0105] The pixel control unit 3 outputs a control signal φ3(H). As a result, the row that received the control signal φ3 is selected. Next, the pixel control unit 3 outputs a control signal φ2(H) for a predetermined period. As a result, a reset drain voltage is output to the floating diffusion layer FD. Next, the pixel control unit 3 outputs a control signal RS(H) for a predetermined period. As a result, the reset level is sampled. Next, the pixel control unit 3 outputs a control signal φ1(H) for a predetermined period. As a result, signal electrons are transferred from the photodiode PD to the floating diffusion layer FD. Next, the pixel control unit 3 outputs a control signal SS(H) for a predetermined period. As a result, the signal level caused by the signal electrons stored in the floating diffusion layer FD is sampled at the timing of the control signal SS(H). Next, the pixel control unit 3 outputs a control signal φ2(H) again for a predetermined period. As a result, a reset drain voltage is output to the floating diffusion layer FD. The potential of the floating diffusion layer FD is reset. The pixel control unit 3 outputs a control signal φ3(L). As a result, readout of the nth row is completed. After that, the pixel control unit 3 outputs the control signal φ3(H) to the next (n+1)th row.

[0106] The signal processing unit 4 creates a difference between the sampled signal level and the reset level. The difference between the sampled signal level and the reset level is correlated double sampling. Correlated double sampling can reduce noise. Correlated double sampling can remove offset. The difference between the sampled signal level and the reset level is treated as a signal component. This signal component is converted from an analog value to a digital value. The component converted into a digital value is then output to the outside of the solid-state imaging device 1.

[0107] FIG. 4 shows a schematic cross section of the pixel section 2. The pixel section 2 is formed on a sensor substrate 12. The sensor substrate 12 has a wiring region 13 and an element region 14. The surface of the sensor substrate 12 on the wiring region 13 side is bonded to a support substrate 11. In addition, a color filter 16 and a microlens 17 are disposed on the pixel section 2. The color filter 16 is responsible for colorization. The microlens 17 is responsible for light collection.

[0108] The wiring region 13 has a plurality of wirings 18, a plurality of vias 19, and gates 21 and 21A. The wirings 18 are formed of copper or aluminum. The vias 19 electrically connect the wirings 18 to each other. The vias 19 electrically connect the wirings 18 to the gates 21 and 21A formed of polysilicon. The wiring region 13 also has an insulating film (not shown) that covers the wirings 18 and the vias 19.

[0109] The element region 14 includes the pixel 8 and the DTI 22 .

[0110] Each pixel 8 has a photoelectric conversion unit 26 and a light scattering unit 27. The photoelectric conversion unit 26 generates a signal voltage according to absorbed light L2 received from the light input surface 26a. The light scattering unit 27 is provided on the light input surface 26a of the photoelectric conversion unit 26. The light input surface 26a also serves as the main surface of a pinning region 36, which will be described later. The light scattering unit 27 receives incident light L1 (see FIG. 5) and generates absorbed light L2 (see FIG. 5), which is output to the photoelectric conversion unit 26.

[0111] The photoelectric conversion section 26 has a first region 29 and a second region 31 .

[0112] The first region 29 includes a base portion 32, a charge accumulation portion 33a, a photodiode pinning layer 33b, and a readout portion 34. The base portion 32 is P-type and constitutes the light input surface 26a. The absorbed light L2 is absorbed in the base portion 32, resulting in the generation of signal electrons. The charge accumulation portion 33a and the photodiode pinning layer 33b are provided between the base portion 32 and the wiring region 13. In other words, the charge accumulation portion 33a is provided near the surface on the wiring region 13 side. The charge accumulation portion 33a cooperates with the P-type base portion 32 and the photodiode pinning layer 33b to form a PN junction diode. The P+-type photodiode pinning layer 33b is provided between the charge accumulation portion 33a and the wiring region 13. The photodiode pinning layer 33b prevents dark current from the interface states on the silicon surface. The photodiode pinning layer 33b contacts the channel stop region 24. The potential of the photodiode pinning layer 33b is the same as the potential of the channel stop region 24.

[0113] The readout section 34 has a threshold adjustment region 34a, N+ regions 34b, 34c, and 34d, and a P-type well 34e.

[0114] The threshold adjustment region 34a contacts the charge accumulation portion 33a and the photodiode pinning layer 33b. The threshold adjustment region 34a cooperates with the gate 21A to form a transfer gate TG. The N+ type region 34b contacts the threshold adjustment region 34a. The N+ type region 34b forms a floating diffusion layer FD. In other words, the N+ type region 34b is provided on the opposite side of the threshold adjustment region 34a to the photodiode PD. That is, the threshold adjustment region 34a is provided between the charge accumulation portion 33a and the floating diffusion layer FD. The P-type well 34e is adjacent to the charge accumulation portion 33a. In other words, the P-type well 34e is adjacent to the charge accumulation portion 33a via the threshold adjustment region 34a.

[0115] The N+ type region 34c is adjacent to the N+ type region 34b across a channel region formed by the P-type well 34e. Signal electrons stored in the charge storage unit 33a are read out to the N+ type region 34b via the threshold adjustment region 34a, which constitutes the transfer gate TG. The N+ type region 34b is a floating diffusion layer FD. The read-out signal electrons are converted into a voltage signal in the floating diffusion layer FD. The N+ type region 34d is adjacent to the N+ type region 34c across a channel region formed by the P-type well 34e. The N+ type region 34d, the N+ type region 34c, and the gate 21 constitute a source follower transistor SF. The channel stop region 24 contacts the N+ type region 34d. Although not shown, a reset transistor RG and a select transistor SEL are also provided.

[0116] The P-type well 34e includes a floating diffusion layer FD, a reset transistor RG, a source follower transistor SF, and a select transistor SEL. The P-type well 34e prevents signal electrons from flowing in from the P-type base portion 32. The P-type well 34e controls the thresholds of the reset transistor RG, the source follower transistor SF, and the select transistor SEL.

[0117] Fig. 5 is an enlarged view of region S1 in Fig. 4. As shown in Fig. 5, the photoelectric conversion body 26 further includes a pinning region 36 formed in the second region 31.

[0118] The pinning region 36 (high concentration impurity layer) is provided on the incident side of the base portion 32. In other words, the pinning region 36 is provided on the surface of the base portion 32 opposite the wiring region 13 side. The thickness of the pinning region 36 is 3 nm or more. The thickness of the pinning region 36 is 100 nm or less. The pinning region 36 has a high acceptor concentration. The pinning region 36 is neutralized. The pinning region 36 holds holes. The pinning region 36 suppresses the generation of dark current. The pinning region 36 will be described in more detail.

[0119] In solid-state imaging device 1 of the present embodiment, a region (photoelectric conversion section) that generates signal electrons due to light absorption includes regions (second region 31, pinning region 36) that function to suppress the generation of dark current. Therefore, between light scattering section 27 and photoelectric conversion section 26, there is substantially no layer or film that blocks absorbed light L2 that is output from light scattering section 27 to photoelectric conversion section 26.

[0120] The sensor will be described as an N-channel type. The signal resulting from the incident light L1 will be described as being carried by signal electrons. The pinning region 36 is of P-type.

[0121] The pinning region 36 is a P+ type pinning layer formed on the surface on the incident side. The pinning region 36 has a high acceptor concentration. The pinning region 36 is always provided with 1×10 17 cm ―3 Holes exist at a concentration of 0.01 or more. Dark current occurs due to the interface states present on the light input surface 26a on the incident side of the photoelectric conversion unit 26. These holes suppress the occurrence of this dark current.

[0122] The pinning region 36 satisfies at least the first condition, and it is even better if the pinning region 36 satisfies the second and third conditions.

[0123] The first condition is that the pinning region 36 accumulates and neutralizes holes on the light-incident surface 26a. This first condition suppresses the generation of dark current at the light-incident surface 26a. When multiple band gap levels are present, such as at the Si / SiO2 interface, electrons in the valence band are excited into conductors via the band gap levels, resulting in the generation of dark current. The value of the dark current is expressed by equation (12), which is based on the Shockley-Read-Hall model.

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[0124] The parameters that make up equation (12) are as follows: U: Recombination rate. σ=σ n =σ p : Capture cross section for electrons and holes in the band gap level. v th :Thermal motion velocity. N t : Band gap level density. n: electron density in the conduction band. p: valence band hole density. n i : intrinsic carrier density. k: Boltzmann's constant. T: Absolute temperature. A positive recombination rate indicates recombination. A negative recombination rate indicates the rate of dark current generation. When the Si / SiO2 interface is depleted, n,p< <n i According to this condition, equation (13) can be obtained from equation (12).

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[0125] This configuration generates a large dark current. On the other hand, when the hole concentration near the interface is large, that is, when p>>n i In the case of n, the band gap level that contributes most to the generation of dark current is E t =E i If , then equation (15) is obtained from equation (12).

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[0126] Equation (16) is the ratio between when the interface is depleted and when holes are accumulated.

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[0127] The second condition is to extend the life of minority carriers. Minority carriers are electrons. In other words, the second condition is that the electrons of the generated electron-hole pairs quickly pass through the P-type photoelectric conversion unit 26 and reach the charge accumulation unit 33a.

[0128] The minority carrier lifetime is affected by the number of crystal defects contained in the pinning region 36. Specifically, the minority carrier lifetime increases as the number of crystal defects contained in the pinning region 36 decreases. Crystal defects are more likely to occur when the pinning region 36 contains a high impurity concentration and has a large high-concentration region. This is because the size of impurity atoms differs from the size of silicon atoms.

[0129] The pinning region 36 is formed by ion implantation. The amount of ions to be implanted corresponds to the integral of the impurity concentration and the impurity distribution. The amount of ions to be implanted that can suppress the occurrence of crystal defects is 3×10 15 cm -2 The following is shown:

[0130] Ion implantation introduces impurities into silicon and simultaneously introduces energy into the silicon. The energy introduced into the silicon also causes crystal defects. Crystal defects can be repaired by annealing, which is performed after ion implantation. However, crystal defects do not completely disappear even with annealing.

[0131] The pinning region 36 is formed after the formation of the wiring region 13 is completed. The annealing method is limited to laser annealing, etc. Therefore, it is necessary to reduce the occurrence of crystal defects caused by ion implantation. The energy introduced into silicon by ion implantation is proportional to the amount of impurity. The energy introduced into silicon by ion implantation is also proportional to the strength of the energy. As a condition for suppressing the occurrence of crystal defects, the product of the amount of impurity and the energy is set to 5×10 15 keV cm -2 It is shown that:

[0132] The third condition is that the electrons of the electron-hole pairs generated by photoelectric conversion must quickly reach the charge accumulation section 33a. The electrons reach the charge accumulation section 33a after passing through the P-type base section 32. This behavior occurs when the electrons move due to drift motion caused by the potential gradient.

[0133] The base portion 32, which is P-type, is depleted. Similarly, the portion of the pinning region 36 with a low impurity concentration on the base portion 32 side is depleted. A sufficient electric field is obtained in the depleted region. Holes are accumulated in the pinning region 36 near the light input surface 26a to suppress dark current. The portion near the light input surface 26a is neutralized. The difference in impurity concentration facilitates the movement of electrons in the non-depleted region.

[0134] The pinning region 36 has an impurity concentration distribution. The higher the acceptor concentration, the smaller the energy difference between the Fermi level and the valence band edge. The concentration of the acceptor impurities decreases in the pinning region 36 from the incident surface toward the base 32. With this impurity concentration distribution, even if there are portions in the pinning region 36 where holes are accumulated, signal electrons will drift quickly to the base 32.

[0135] Such an impurity concentration distribution is obtained by ion implantation. Specifically, it is obtained by setting the peak position of the impurity concentration distribution at the light input surface 26a. The peak position of the impurity concentration distribution may also be set in an oxide film provided on the light input surface 26a. By setting the peak position in this way, an impurity concentration distribution is formed in which the impurity concentration monotonically decreases from the light input surface 26a toward the base portion 32.

[0136] The impurity concentration distribution can also be achieved under other conditions. Ion implantation is performed at a low energy of, say, 0.2 keV. As a result, the peak position in the impurity concentration distribution is approximately 0.5 nm. When a device with such a distribution is annealed, the peak almost disappears. As a result, an impurity concentration distribution is obtained in which the impurity concentration monotonically decreases from the incident surface toward the base portion 32. The implantation energy is preferably, for example, 1 keV or less. A method using low-energy ion implantation does not form an oxide film. As a result, a method using low-energy ion implantation has the advantage of eliminating the complicated process of removing the oxide film after ion implantation. The following description focuses on the method of forming the pinning region 36 using low-energy ion implantation.

[0137] (Light scattering part) The inventors have conducted extensive research into further improving the sensitivity of the image sensor shown in Patent Document 1 and other publications. As a result, the inventors have discovered that one of the main reasons for the insufficient improvement in sensitivity is insufficient scattering of light in the light scattering portion. The results of studying the characteristics of the pyramidal scattering layer or the randomly asperity-shaped scattering layer will be described in detail in the following sections, "First Study" and "Second Study."

[0138] The inventors have come up with the structure shown in FIG. 6 as a light scattering structure that sufficiently scatters light. The structure shown in FIG. 6 scatters incident light L1 by diffraction using plasmons. Equation (17) shows the relationship between variables related to the light scattering structure. The light scattering structure is made up of a plurality of metal structures 27a. The plurality of metal structures 27a are arranged according to a fixed period. The light scattering structure is a periodic structure. In the light scattering structure, diffracted light is considered to be generated due to plasmons. The diffracted light is calculated by dividing the scattering angle θ in Equation (17). d In other words, the scattering angle θ d is 90 degrees less than In the diffraction mode, propagating light is generated in silicon. θ d is 90 degrees The above In this case, it is a localized enhanced field mode.

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[0139] Diffracted light generated by ordinary diffraction phenomena includes zero-order light that travels straight without being diffracted. Diffracted light is divided into two parts by the diffraction angle (scattering angle θ d ) of the diffracted light. First, light scattering section 27 is required to reduce the proportion of zero-order light. Second, light scattering section 27 is required to reduce the diffraction angle (scattering angle θ d) is required to be large. Thirdly, light scattering section 27 is required to have a small reflectance. In equation (17), l = 1 indicates the range in which primary light can be used as scattered light. When l = 2, it indicates the range in which secondary light can be used as scattered light. When secondary light is also used as scattered light, the average scattering angle of the intensity-weighted primary and secondary light becomes smaller than when only primary light is used. However, the periodic length of the metal structure only needs to be doubled. As a result, there is an advantage that the degree of microfabrication is less. Ordinary diffraction phenomena are not suitable for use as light scattering section 27. This is because ordinary diffraction phenomena have a large proportion of zero-order light and a high reflectance.

[0140] In the diffraction mode utilizing plasmons, diffracted light is generated by the vibration of electric dipoles induced in the lower part (silicon side) of the metal structure 27a. The diffracted light is considered to be emitted from the center of the vibration of the electric dipoles.

[0141] The light scattering portion 27 is a metal film formed on the surface of the pinning region 36. The light scattering portion 27 is in direct contact with the pinning region 36. The light scattering portion 27 is formed of a material selected from the group consisting of silver, aluminum, gold, copper, and titanium nitride. The light scattering portion 27 may be formed of a material selected from the group consisting of a material containing silver as a main component, a material containing aluminum as a main component, a material containing gold as a main component, a material containing copper as a main component, and a material containing titanium nitride as a main component. The thickness of the light scattering portion 27 is 10 nm or more. The thickness of the light scattering portion 27 is 30 nm or less.

[0142] Light scattering section 27 is separated from the light scattering section 27 of another pixel 8 adjacent to the pixel 8. This separation means that plasmons generated in one light scattering section 27 do not move to the other adjacent light scattering section 27. In other words, a gap is provided at the boundary between pixels 8. The movement of plasmons generated in one light scattering section 27 to the other adjacent light scattering section 27 is also called plasmon interference. This gap makes it possible to suppress plasmon interference between pixels 8.

[0143] Light scattering portion 27 generates scattered light generated by plasmons. The presence of the gap reduces the area of ​​light scattering portion 27. Solid-state imaging device 1 has microlens 17 (see FIG. 4). Microlens 17 is provided on light scattering portion 27. Microlens 17 makes it possible to focus incident light L1 onto light scattering portion 27. As a result, a decrease in sensitivity can be prevented.

[0144] Light scattering section 27 may include a concave-convex structure. The concave-convex structure includes a plurality of metal structures 27a (a plurality of convex portions). Metal structures 27a protrude from light input surface 26a.

[0145] Light scattering section 27 may employ various structures capable of generating diffracted light generated by plasmons. Light scattering section 27 may include a periodic structure. The periodic structure may be, for example, a structure having a plurality of spherical particles. The periodic structure may be, for example, a structure having a plurality of columnar particles. Such structures can be classified into pattern structures and particulate structures.

[0146] Examples of pattern structures include diffraction gratings, hole arrays, disk arrays, slit arrays, antenna arrays, and bull's-eye arrays. The diffraction grating may be, for example, a one-dimensional array structure in the form of stripes. The diffraction grating may be, for example, a two-dimensional array structure in the form of a square lattice. The diffraction grating may be, for example, a two-dimensional array structure in the form of a triangular lattice. The hole array may have holes with a circular, rectangular, or triangular shape. The disk array may have disks with a circular, rectangular, triangular, or hemispherical shape. The slit array may have slits with a one-dimensional structure, a cross structure, or an asterisk structure. The slit array may have each structure arranged in a square lattice or triangular lattice shape. The antenna array may have a particle pair structure, a rod pair structure, or a bowtie structure. The bull's-eye array may have a structure including an aperture and a concentric concave-convex structure arranged in a square lattice or triangular lattice shape.

[0147] Examples of the microparticle structure include microparticles formed from a metal material. Examples of metal materials that may be used include aluminum, silver, gold, and copper. Examples of the shape of the microparticle include spherical nanoparticles, metal nanoshells, metal nanorods, and metal nanowires. The microparticle structure utilizes localized surface plasmon resonance. When spherical nanoparticles are used as the microparticle structure, a gap mode that operates between particles is applied. As a result, near-infrared resonance can be obtained. The diameter of the spherical nanoparticles and nanoshells may be 10 nm or more. The diameter of the spherical nanoparticles and nanoshells may be 1 μm or less. The diameter of the nanorods and nanowires may be 10 nm or more. The diameter of the nanorods and nanowires may be 300 nm or less. The length of the nanorods and nanowires may be 50 nm or more. The length of the nanorods and nanowires may be 10 μm or less. Examples of materials that form the microparticle structure include nitride-based nanoparticles such as TiN and high-refractive-index nanoparticles such as Si that utilize Mie scattering. These fine particle structures may be formed by chemical synthesis, sputtering, or vacuum deposition, which allows the formation of island-shaped films with grain structures.

[0148] The periodic length of a structure utilizing surface plasmon resonance based on periodicity is preferably 100 nm or more and less than the wavelength. In a structure utilizing surface plasmon resonance based on gap mode, the intermetallic distance between particle pairs or the like is preferably less than the wavelength. For example, the intermetallic distance is preferably 1 nm or more. More preferably, the intermetallic distance is 100 nm or less. The structure may be formed by excimer laser lithography, electron beam lithography, focused ion beam processing technology, or the like.

[0149] (DTI) Further investigation by the inventors has led to the identification of factors that could lead to further improvement in sensitivity: the insufficient improvement in sensitivity and the occurrence of crosstalk are due to the configuration of the DTI 22.

[0150] The DTI 22 is provided between adjacent pixels 8. The DTI 22 has a deep trench 22a and a light reflecting portion 22b. The deep trench 22a is provided on the incident side. The light reflecting portion 22b is formed of a metal material embedded in the deep trench 22a. The channel stop region 24 is provided on the wiring region 13 side. A charge storage portion 33a, a floating diffusion layer FD, and the like are provided in the region sandwiched between the deep trenches 22a. The deep trench 22a suppresses optical crosstalk between the pixels 8. The deep trench 22a suppresses crosstalk due to diffusion of signal electrons. The channel stop region 24 electrically isolates the pixels 8 from each other. More specifically, the channel stop region 24 electrically isolates the charge storage portion 33a and the N+ type region 34d.

[0151] As shown in FIG. 7, the DTI 22 optically separates adjacent pixels 8 from each other. Therefore, it is desirable that the DTI 22 ideally reflect all light and not transmit all light. If the light reflectivity and light blocking properties of the DTI 22 are insufficient, the DTI 22 will not be able to reflect enough light. As a result, some light will transmit through the DTI 22. Light leaking into adjacent pixels 8 can cause crosstalk.

[0152] FIG. 8 shows calculated values ​​of reflectance when light is perpendicularly incident from the first member to the second member. The first member is made of silicon. The second member is made of silver (Ag: graph G8a), copper (Cu: graph G8b), aluminum (Al: graph G8c), silicon oxide (SiO2: graph G8d), and silicon dioxide (SiO2: graph G8e). e ), Tungsten (W: Graph G8 d ) The horizontal axis indicates the wavelength of light in a vacuum. The vertical axis indicates the reflectance. For example, the wavelength of light used in the ToF method is 850 nm or 940 nm. Conventional image sensors are made of silicon oxide (Graph G8 e ) or tungsten (Graph G8 d In this case, the reflectance was found to be 20% or less.

[0153] To improve sensitivity, light must pass through the P-type substrate multiple times. After passing through the P-type substrate, the light enters the DTI 22. The incident light is reflected by the DTI 22. The light then passes through the P-type substrate again. This repeated passage through the P-type substrate and reflection by the DTI 22 extends the optical path length L that contributes to light absorption. Increasing the number of reflections in the DTI 22 further extends the optical path length L. Increasing the reflectivity R of the DTI 22 is important to increase the number of reflections in the DTI 22.

[0154] For example, let us assume that the DTI 22 completely reflects light. When light is completely reflected, the reflectance can be expressed as R=1. Assuming that the reflectance R=1, the optical path length L can be expressed by equation (18). According to equation (18), it can be seen that the optical path length L is proportional to the number of reflections k.

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[0155] Next, we will consider the case where the reflectance is less than 1. When the reflectance is less than 1, the optical path length L can be expressed by equation (19). The effective optical path length L becomes shorter depending on the amount of attenuation due to reflection. According to equation (19), the attenuation of reflected light with respect to the number of reflections k can be expressed by a geometric progression. Figure 9 shows a schematic diagram of how light is attenuated each time it is reflected at a reflectance R.

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[0156] In equation (19), the second factor in the second term on the right-hand side is called the effective magnification EM. The relationship between the number of reflections k and the effective magnification EM was confirmed. The results of this study are shown in Figure 10. Figure 10 shows the relationship between the number of reflections k and the effective magnification EM. The horizontal axis represents the number of reflections, and the vertical axis represents the effective magnification EM. Specifically, Figure 10 shows the effective magnification EM when the number of reflections k is 1 to 14. The correspondence between each of the graphs G10a to G10j and the effective magnification EM is as follows: Graph G10a: R =1.0. Graph G10b: R =0.9. Graph G10c: R =0.8. Graph G10d: R =0.7. Graph G10e: R =0.6. Graph G10f: R =0.5. Graph G10g: R =0.4. Graph G10h: R =0.3. Graph G10i: R =0.2. Graph G10j: R =0.1.

[0157] The relationship between reflectance R and effective magnification EM was confirmed when the number of reflections k is infinite. The results are shown in Figure 11. The horizontal axis represents reflectance R. The vertical axis represents effective magnification EM. Referring to graph G11, it can be seen that even with infinite reflections, when reflectance R is small, effective magnification EM remains small. It can also be seen that effective magnification EM increases rapidly when reflectance R exceeds 0.8. The results shown in Figure 11 indicate that it is desirable for the reflectance R of the DTI22 to be 0.8 or greater.

[0158] We investigated the configuration of the DTI22 that can achieve a reflectance R of 0.8 or more. The reflectance R is the reflectance R of light incident from silicon to the buried material that constitutes the DTI22. Based on the complex refractive index of the buried material, we investigated a configuration that can achieve the desired reflectance R. For simplicity, we assumed normal incidence. As a result, the reflectance R is obtained by equation (20).

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[0159] FIG. 12 is a list of refractive indices for various materials. Substituting the complex refractive index of silicon shown in FIG. 12 into equation (20), we can determine the relationship between n2 and k2 when R=0.8. FIG. 13 shows this relationship as graph G13. The horizontal axis indicates the real part n2. The vertical axis indicates the imaginary part k2. The diamond-shaped marker M13a corresponds to a wavelength of 800 nm. The cross-shaped marker M13b corresponds to a wavelength of 1100 nm. The markers M13a and M13b almost overlap with each other. Furthermore, values ​​from 800 nm to 1100 nm show roughly the same tendency. In other words, the markers M13a and M13b almost overlap with each other. In the upper left region A13, based on the markers M13a and M13b, the reflectance is 0.8. End Graph G13 is a linear approximation of markers M13a and M13b. Using graph G13, the condition for the reflectance R to be 0.8 or more is expressed by equation (21).

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[0160] FIG. 8 shows that silver and copper have high reflectance R in the near-infrared region with wavelengths of 800 nm or more. In the near-infrared region with wavelengths of 800 nm or more, silver and copper are suitable materials to be embedded in the DTI 22. Looking at the complex refractive index values ​​shown in FIG. 12, silver and copper satisfy formula (21). Silver or copper is the most preferable material for the DTI 22. Gold, platinum, and bismuth also satisfy formula (21). Therefore, gold, platinum, and bismuth are also preferable materials for the DTI 22.

[0161] FIG. 14 is a list of the complex refractive index, reference material, reflectance R relative to silicon, real part of dielectric constant, and imaginary part of dielectric constant of various materials. These values ​​are for a wavelength of 940 nm. When reflectance R is used as the reference, materials with a reflectance R of 0.8 or higher are silver, copper, lithium, gold, and bismuth. From the viewpoint of material stability, it is preferable to select silver, copper, gold, and bismuth from among these.

[0162] The optical characteristics of the DTI22 are affected not only by the type of embedded material but also by the thickness of the embedded material. The optical characteristic is transmittance. Transmittance affects crosstalk. We will now consider the thickness and transmittance of the embedded material that makes up the DTI22. Figure 15(a) is a schematic diagram of the analytical model used for this study. Figure 15(b) shows the relationship between film thickness and reflectance R. The horizontal axis represents film thickness, and the vertical axis represents reflectance R. The relationship between each graph and the embedded material is as follows: Silver: Graph G15a. Copper: Graph G15b. Aluminium: Graph G15c. Silicon oxide: Graph G15d. Tungsten: Graph G15e.

[0163] The thickness of the buried material is the same as the groove width of the DTI22. Crosstalk is roughly correlated with transmittance. If the crosstalk that can withstand normal practical use is set to 5% or less, the transmittance should be set to 5% or less. The thickness of the buried material should be equal to or greater than the following value. Silver: film thickness 45 nm. Copper: film thickness 50 nm. Aluminum: film thickness 35 nm.

[0164] 15(c) shows the relationship between film thickness and transmittance. The horizontal axis represents film thickness, and the vertical axis represents transmittance. The relationship between each graph and the buried material is as follows: Silver: Graph G15i. Copper: Graph G15h. Aluminum: Graph G15j. Silicon oxide: Graph G15f. Tungsten: Graf G 15g. For example, referring to graphs G15a to G15e in Fig. 15(b), it was found that the reflectance of aluminum (graph G15c) is not as high as that of silver (graph G15a) and copper (graph G15b). Referring to graph G15j in Fig. 15(c), it was found that aluminum has the excellent property of having a low transmittance.

[0165] As a result of the above considerations, the types of metals that can be used as the embedding material for the DTI 22 and the width of the DTI 22 set for each type of metal are listed below. In this specification, the "width of the DTI 22" may be interpreted as the width of the deep trench 22a. The "width of the DTI 22" may be interpreted as the width of the light reflecting portion 22b.

[0166] When the buried material is silver or a material containing silver as a main component, the width of the DTI 22 is 45 nm or more.

[0167] When the buried material is copper or a material containing copper as a main component, the width of the DTI 22 is 50 nm or more.

[0168] When the buried material is gold or a material containing gold as a main component, the width of the DTI 22 is 60 nm or more.

[0169] When the buried material is platinum or a material containing platinum as a main component, the width of the DTI 22 is 30 nm or more.

[0170] When the buried material is bismuth or a material containing bismuth as a main component, the width of the DTI 22 is 70 nm or more.

[0171] When the buried material is aluminum or a material containing aluminum as a main component, the width of the DTI 22 is 35 nm or more.

[0172] The DTI22 may have a negative charge holding film to prevent dark current from the trench interface. Aluminum oxide may be used as the negative charge holding film. Silicon nitride may also be used as the negative charge holding film. We investigated the effect of the negative charge holding film on reflectance and transmittance. In Figures 15(b) and 15(c), the dashed lines indicate the results when a negative charge holding film is present. A 5-nm-thick alumina layer was used as the negative charge holding film, sandwiched between the silicon and metal. In both Figures 15(b) and 15(c), the presence or absence of the negative charge holding film did not significantly affect the relationship between film thickness and reflectance. The same was true for transmittance. Specifically, the negative charge holding film did not significantly affect the relationship between film thickness and transmittance.

[0173] The inventors have also considered the DTI 22 from another perspective. In the above discussion of the DTI 22, attention was focused on the material that constitutes the DTI 22. The inventors have further considered the spacing W between adjacent DTIs 22. PD Specifically, the light diffracted by the metal plasmonic structure is repeatedly reflected by the DTI 22. As a result, the diffracted light forms an interference field as a standing wave. The distance W between the first DTI 22 (first isolation wall) and the second DTI 22 (second isolation wall) PD satisfies the constructive interference condition in standing waves. The spacing W PD The efficiency of light absorption can be maximized by setting

[0174] As shown in FIG. 16, the interval W PD The interval W between the first DTI 22 and the second DTI 22 is defined as PD is the width of the photoelectric conversion unit 26 sandwiched between the first DTI 22 and the second DTI 22. PD is defined by equation (22).

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[0175] Variable X L and variable X R satisfies equation (23).

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[0176] Distance W between metal structures 27a metal If you do not define PD may be defined by equation (24).

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[0177] The above-mentioned interval W PD The above argument is valid when the light scattering portion 27 has a periodic structure. PDIn the discussion above, it is important to have a structure that scatters light and to satisfy the condition of constructive interference in standing waves. It is not an essential requirement that the light scattering section 27 has a periodic structure. When the light scattering section 27 has a non-periodic structure in which the periodic length P cannot be defined, the spacing W PD The discussion of this will be explained in the section on variations.

[0178] <Method of manufacturing a solid-state imaging device> A method for manufacturing the solid-state imaging device 1 will now be described.

[0179] A silicon wafer is prepared. Next, components such as the charge accumulation portion 33a, photodiode pinning layer 33b, transistors, and wiring 18 are formed on a portion of the silicon wafer that will be on the wiring region 13 side of the solid-state imaging device 1. This process forms the sensor substrate 12. Next, the sensor substrate 12 is bonded to the support substrate 11. In this process, the surface on which the charge accumulation portion 33a and the like are formed is bonded to the support substrate 11. A wafer on which a circuit is formed may be used as the support substrate 11. When a wafer on which a circuit is formed is used as the support substrate 11, the degree of integration can be further increased.

[0180] Next, the thickness of the sensor substrate 12 is adjusted. Specifically, the sensor substrate 12 is removed from the light input surface 26a of the sensor substrate 12. The thickness of the sensor substrate 12 is 2 μm or more and 4 μm or less when used for normal visible light. When used for near-infrared light, a sensor substrate 12 with a thickness of 2 μm or more and 4 μm or less is usually unable to sufficiently absorb near-infrared light. According to the configuration of the solid-state imaging device 1, even if the thickness of the sensor substrate 12 is 2 μm or more and 4 μm or less, it is possible to sufficiently detect near-infrared light.

[0181] Next, the pinning region 36 is formed. Specifically, boron ions are implanted into the light input surface 26a of the sensor substrate 12. The ion implantation energy is at least 0.2 keV. The ion implantation energy is 0.2 keV or more. The ion implantation energy is 1 keV or less. After the ion implantation, laser annealing is performed for activation. The ion implantation may be performed through an oxide film. In this case, the peak of the impurity concentration in the impurity concentration distribution occurs at the interface on the incident side or in the oxide film. The ion implantation dose is 1×10 14 cm ―3 The ion implantation dose is preferably 3×10 15 cm ―3 The following is desirable. Next, after the ion implantation, laser annealing is performed. Laser annealing allows annealing to be performed without damaging the transistors and wiring formed on the wiring region 13 side. When performing laser annealing, the energy of the laser annealing is reduced. In other words, when performing laser annealing, silicon is not melted. By satisfying this condition, it is possible to prevent the impurity concentration in the melted portion from becoming constant. By performing laser annealing under conditions that do not melt silicon multiple times, it is possible to change a state of insufficient impurity activity to a state of sufficient impurity activity. A deep trench 22a is formed to prevent crosstalk.

[0182] A method for forming the DTI 22 from the back surface (incident surface) side will be described. The method for forming the DTI 22 includes an etching step S1 for digging a deep trench 22a and a step S3 for filling the deep trench 22a with metal. A hard mask 101 is formed on the main surface of a P-type substrate 100. Next, the deep trench 22a is formed. The deep trench 22a is formed by alternately repeating an anisotropic etching step and a sidewall protective film formation step multiple times (see FIG. 17(a)). This process allows the formation of a deep trench 22a with a large aspect ratio (the ratio of the width to the depth of the DTI 22).

[0183] Next, as shown in FIG. 17(b), an alumina (Al2O3) film of approximately 5 nm is formed on the inner surface of the deep trench 22a (step S2). The alumina (Al2O3) film is a negative charge retention film 52. The hard mask 101 is removed. Next, a film is formed. ALD (Atomic Layer Deposition) may be used to form the film. The ALD process allows a uniform film to be formed on the deep trench 22a, which has a large aspect ratio. The negative charge retention film 52 of the DTI 22 and a negative charge retention film (not shown) on the backside may be formed in the same process. The negative charge retention film 52 accumulates holes at the interface of the deep trench 22a. As a result, dark current from the interface state is suppressed.

[0184] 17(c), a material that will become the light reflecting portion 22b is placed in the deep trench 22a. Atomic layer deposition may be used in step S3. The relationship between the filling material and the source gas (precursor) is as follows:

[0185] When the filling material is silver, a source gas containing silver is used. As the source gas containing silver, "triethylphosphine(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate)silver(I)" may be used.

[0186] When the filling material is copper, a source gas containing copper is used. The following gases may be used as the source gas containing copper. "Bis(2,2,6,6-tetramethyl-3,5-heptanedionate)copper(II)" (Cu(thd)2, (thd = 2,2,6,6-tetramethyl-3,5-heptane dionate, Cu(OCC(CH3)3CHCOC(CH3)3)2)). "Bis(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)copper(II)" (Cu(OCC(CH3)3CHCOCF2CF2CF3)2)).

[0187] When the filling material is gold, a source gas containing gold is used. The following gases may be used as the source gas containing gold. Trimethyl(trimethylphosphine)gold(III) (Me3AuPMe3 (Me=Methyl)).

[0188] When the filling material is aluminum, a source gas containing aluminum is used. The following gases may be used as the source gas containing aluminum. · Trimethylaluminum (Al(CH3)3, TMA). Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)aluminum (Al(C 11 H 19 O2)3, Al(DPM)3). · Triethylaluminum (Al(C2H5)3, TEA).

[0189] When the filling material is bismuth, a source gas containing bismuth is used. The following gases may be used as the source gas containing bismuth. Triphenylbismuth (Ph)3 (Ph=phenyl) Tris(2,2,6,6-tetramethyl-3,5-heptanedionate) bismuth (2,2,6,6Tetramethyl-3,5-heptanedionate(III)Bi(Bi(TMHD)3)). Bis(acetato-O)triphenylbismuth (Ph3Bi(Oас)2, (CH3CO2)2Bi(C6H5)3) (see also the chemical formula below). Tris(2-methoxyphenyl)bismuthine ((CH3OC6H4)3Bi) Tri(tert-butyloxy)bismuth (Tri-tert-butoxybismuth(III), Tri(tert-butyloxy)bismuth). · Tris(1,1,2-trimethylpropyloxy)bismuth. · Tris(1,1-diisopropyl-2-methylpropyloxy)bismuth.

[0190] When the filling material is platinum, a source gas containing platinum is used. The following gases may be used as the source gas containing platinum. "Trimethyl(methylcyclopentadienyl)platinum(IV) (C5H4CH3Pt(CH3)3).

[0191] In the above source gases, the number of carbon atoms in the hydrocarbon group may be at least 1. Other source gases that may be used include M(C5H5)2 or (CH3C5H4)M(CH3)3.

[0192] Next, the filling material deposited outside the deep trench 22a is removed by chemical mechanical polishing (CMP).

[0193] Next, as shown in FIG. 17(d), a protective film 53 is formed (step S4). The protective film 53 can suppress corrosion of the silver or copper embedded in the deep trench 22a. The protective film 53 may be made of alumina. The negative charge holding film 52 may also serve as the protective film 53. The protective film 53 may be provided separately from the negative charge holding film 52.

[0194] Next, after the deep trench is formed, the light scattering portion 27 is formed.

[0195] Color filters 16 and microlenses 17 are formed on light scattering portions 27. Through the above steps, solid-state imaging device 1 can be obtained.

[0196] <Action and effect> The solid-state imaging device 1 diffracts incident light L1 by the light scattering section 27 including a plurality of metal structures 27a. The diffraction of light by the light scattering section 27 including a plurality of metal structures 27a is caused by the plasmon phenomenon. The generation of diffracted light can be controlled by the periodic length P that defines the arrangement of the plurality of metal structures 27a. Therefore, as shown in equation (25), the desired scattering angle θ d As a result, it is possible to ensure the optical path length L determined by the wavelength λ of the incident light L1 and the light absorption characteristics of the photoelectric conversion section 26. Therefore, the photoelectric conversion efficiency of near-infrared light can be further improved.

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[0197] In a solid-state imaging device 1 having a configuration that satisfies formula (26), the proportion of zero-order diffracted light that travels straight in the thickness direction of the photoelectric conversion section 26 decreases. The proportion of diffracted light of orders that travel in directions oblique to the thickness direction of the photoelectric conversion section 26 increases. As a result, the amount of diffracted light and propagation distance in the photoelectric conversion section 26 can be adjusted to desired levels. Therefore, the photoelectric conversion efficiency of near-infrared light can be further improved.

number

[0198] The DTI 22 formed from a metal that satisfies formula (27) can effectively reflect diffracted light, thereby further increasing the photoelectric conversion efficiency of near-infrared light.

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[0199] Metals have unique optical properties in the near-infrared region. In other words, metals have unique complex refractive indices in the near-infrared region. Therefore, the selection of the metal for forming the light-reflecting portion 22b is important. Without the light-scattering portion 27, the angle of the incident light L1 does not change significantly. The angle of incidence on the side surface of the DTI 22 increases. As a result, total reflection may occur in some cases. Therefore, the reflectance R may increase. With the light-scattering portion 27, the angle of incidence on the side surface of the DTI 22 may decrease. According to Equation (26), it is possible to construct a DTI 22 formed from a metal suitable for the near-infrared region. As a result, the reflectance R of the DTI 22 can be increased. The transmittance of the DTI 22 can also be reduced. Furthermore, the DTI 22 can be miniaturized.

[0200] Although the embodiments of the present invention have been described above, the solid-state imaging device of the present invention is not limited to the above embodiments.

[0201] (Variation: Optimal trench spacing in non-periodic structures) The spacing W of the DTI 22 when the light scattering portion 27 has a non-periodic structure PD When the silicon light receiving surface has a pyramidal shape, a triangular prism structure, or a random uneven structure, it can be said that the light scattering section 27 has a non-periodic structure. When the light scattering section 27 has a non-periodic structure, the structure is not specified by a variable such as the periodic length P. The spacing W is determined by using the interference condition that the spacing W is an integer multiple of the propagation wavelength inside the photoelectric conversion section 26. PD According to this definition, the period length P and the number of periods M are unnecessary. The definition is in the form of an integer multiple of the propagation wavelength plus an offset range.

[0202] The spacing W of the DTI 22 when the light scattering portion 27 has a non-periodic structure PD can be defined by equation (28).

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[0203] As shown in FIG. 18, light scattering section 27 may include a first periodic structure 27M1 and a second periodic structure 27M2.

[0204] The first periodic structure 27M1 includes a plurality of metal structures 27a. The metal structures 27a are arranged at equal intervals along a first direction D1. The arrangement of the metal structures 27a is defined by a first periodic length P1. The first periodic length P1 may be determined based on the wavelength λ of the incident light L1. The first periodic length P1 is determined based on the scattering angle θ d It may be determined based on the following.

[0205] The second periodic structure 27M2 includes a plurality of metal structures 27a. The metal structures 27a may be the same as the metal structures 27a that constitute the first periodic structure 27M1. The metal structures 27a may also be different metal structures 27a. The light-scattering portion 27 in FIG. 18 illustrates a case in which the metal structures 27a that constitute the second periodic structure 27M2 are the same as the metal structures 27a that constitute the first periodic structure 27M1.

[0206] The metal structures 27a are arranged at equal intervals along a second direction D2. The second direction D2 is inclined with respect to the first direction D1. The second direction D2 is not parallel to the first direction D1. In the example shown in FIG. 18, the second direction D2 is perpendicular to the first direction D1. The arrangement of the metal structures 27a is defined by a second periodic length P2. The second periodic length P2 may be determined based on the wavelength λ of the incident light L1. The second periodic length P2 is determined based on the scattering angle θ dThe second periodic length P2 may be determined based on the second periodic structure 27M2. The second periodic length P2 is different from the first periodic length P1. For example, the wavelength λ of the incident light L1 targeted by the second periodic structure 27M2 may be made different from the wavelength λ of the incident light L1 targeted by the first periodic structure 27M1. The second scattering angle θ by the second periodic structure 27M2 may be determined based on the second periodic structure 27M2. d is the first scattering angle θ by the first periodic structure 27M1. d can be made different from.

[0207] 19, the solid-state imaging device 1A may include a charge holding film 81. The charge holding film 81 is provided between the light scattering section 27 and the photoelectric conversion section .

[0208] In this specification, elemental technologies for improving the photoelectric conversion efficiency of a solid-state imaging device have been described. The elemental technologies for improving the photoelectric conversion efficiency include, first, a large scattering angle θ d The second element is a technology for obtaining a large reflectance R in the DTI 22. The third element is a technology for forming a standing wave in the photoelectric conversion section 26. The first element is the use of diffracted light generated by plasmons in a fine metal structure. The second element is the selection of an optimal metal material for constructing the DTI 22. The third element is the selection of the spacing W of the DTI 22. PD In other words, the third elemental technology is the optimization of the width of the photoelectric conversion section 26. A solid-state imaging device that incorporates all of the first, second, and third elemental technologies can achieve the best photoelectric conversion efficiency. If a solid-state imaging device incorporates at least one of the three elemental technologies, it can achieve the effect of improving photoelectric conversion efficiency.

[0209] The solid-state imaging device that is the subject of the present invention will be listed below based on three elemental technologies.

[0210] The solid-state imaging device according to the first aspect includes all of the first, second, and third elemental technologies. This solid-state imaging device is the one described in the embodiment.

[0211] The solid-state imaging device according to the second aspect includes the first elemental technology and the second elemental technology. PD may take any value.

[0212] The solid-state imaging device according to the third aspect includes the first elemental technology and the third elemental technology. The material of the DTI 22 according to the second elemental technology may be any material.

[0213] The solid-state imaging device according to the fourth aspect includes the first element technology. The material of the DTI 22 according to the second element technology may be any material. The spacing W of the DTI 22 according to the third element technology PD may take any value.

[0214] A solid-state imaging device according to a fifth aspect includes the second and third elemental technologies. The light scattering portion according to the first elemental technology does not need to generate scattered light by plasmons. The solid-state imaging device according to the fifth aspect may employ a light scattering portion having a periodic structure. For example, as shown in FIG. 20(a), a solid-state imaging device 1B may employ a pyramidal scattering layer or a triangular prism array scattering layer as light scattering portion 27B.

[0215] The solid-state imaging device of the sixth aspect includes the second elemental technology. The light scattering portion of the first elemental technology does not have to generate scattered light by plasmons. The solid-state imaging device of the sixth aspect may employ a light scattering portion having a periodic structure. For example, a pyramidal scattering layer or a scattering layer of a triangular prism array may be employed as the light scattering portion. The spacing W of the DTI 22 of the third elemental technology PD may take any value.

[0216] A seventh aspect of the solid-state imaging device includes the third elemental technology. The light scattering portion according to the first elemental technology does not have to generate scattered light by plasmons. The seventh aspect of the solid-state imaging device may employ a light scattering portion having a periodic structure. For example, a pyramidal scattering layer may be employed as the light scattering portion. In other words, any material may be employed as the material for the DTI 22 according to the second elemental technology.

[0217] The solid-state imaging device of the eighth aspect includes the second and third elemental technologies. The light scattering portion related to the first elemental technology does not have to generate scattered light by plasmons. As shown in FIG. 20(b), the solid-state imaging device 1C of the eighth aspect may employ a light scattering portion 27C having a non-periodic structure. For example, a scattering layer with a randomly uneven shape may be employed as the light scattering portion.

[0218] The solid-state imaging device of the ninth aspect includes the second elemental technology. The light scattering portion according to the first elemental technology does not have to generate scattered light by plasmons. The solid-state imaging device of the ninth aspect may employ a light scattering portion having a non-periodic structure. For example, a scattering layer with a random unevenness may be employed as the light scattering portion. The spacing W of the DTI 22 according to the third elemental technology PD may take any value.

[0219] A tenth aspect of the solid-state imaging device includes the third elemental technology. The light scattering portion according to the first elemental technology does not have to generate scattered light by plasmons. The tenth aspect of the solid-state imaging device may employ a light scattering portion having a non-periodic structure. For example, a scattering layer with a randomly irregular shape may be employed as the light scattering portion. In other words, any material may be employed as the material for the DTI 22 according to the second elemental technology.

[0220] We investigated the characteristics when a pyramidal scattering layer or an isosceles triangular prism scattering layer was used as the light scattering structure. In the investigation, we assumed that light is incident on silicon from a silicon oxide film, as shown in Figure 21(a). Symbol L1 is the incident light. Symbol LA is the refracted light (scattered light). Symbol LB is the reflected light. Symbol δ is the angle of incidence. Symbol θ2 is the angle of refraction. Symbol α is the inclination angle of the incident surface. Symbol θ d is the scattering angle. Scattering angle θ d is the sum of the refraction angle and the inclination angle α of the incident surface. In the first study, we obtained the characteristics when the number of reflections was one. In the second study, we obtained the characteristics when the number of reflections was three.

[0221] The results of some studies carried out on solid-state imaging devices will be described below.

[0222] (First Consideration) FIG. 21(b) shows the results of the first study. The horizontal axis represents the inclination angle α of the incident surface. The inclination angle α of the incident surface corresponds to the inclination of the pyramidal surfaces constituting light scattering section 27S or the inclination of one surface forming random irregularities. The first vertical axis represents the reflectance R (graph G21a). The second vertical axis represents the scattering angle θ d (Graph G21b) is shown. The reflectance R is shown as the average value of S-polarized light and P-polarized light. The wavelength λ of the light was 940 nm.

[0223] According to graph G21b, the scattering angle θ d It was found that is proportional to the inclination angle α of the incident surface. According to graph G21a, it was found that the reflectance R increases rapidly when the inclination angle α of the incident surface is greater than 50 degrees. If the allowable value of the reflectance R is 0.3, the inclination angle α of the incident surface when the reflectance R is 0.3 is 73 degrees. The scattering angle θ when the reflectance R is 0.3 d is 50 degrees. Scattering angle θ d The larger the scattering angle θ, the longer the optical path length L can be. d It is preferable to set the scattering angle θ to a large value. dAccording to the conditions for increasing R, the reflectance R increases. Therefore, it was found that the amount of light incident on the photoelectric conversion section 26 decreases in the first place.

[0224] (Second Consideration) The characteristics were calculated when an array of isosceles triangular prisms was used. Figures 22(a) to (d), 23(a) to (d), and 24(a) show schematic diagrams of the path of light. In each figure, the inclination angle α of the incident surface differs as listed below. Symbol L1 is the incident light. Symbol LA is the refracted light (scattered light). Symbol LB is the reflected light. Symbol LA2 is the second refracted light. Symbol LB2 is the second reflected light. Figure 22(a): Tilt angle α<60 degrees. Figure 22(b): Tilt angle α = 60 degrees. Figure 22(c): 54 degrees < tilt angle α < 60 degrees. Figure 22(d): Tilt angle α = 54 degrees. Figure 23(a): 45 degrees < tilt angle α < 54 degrees. Figure 23(b): Tilt angle α = 45 degrees. Figure 23(c): 30 degrees < tilt angle α < 45 degrees. Figure 23(d): Tilt angle α = 30 degrees. Figure 24(a): 0 degrees < tilt angle α < 30 degrees.

[0225] According to Figure 22(a), when the tilt angle α is less than 60 degrees, two or three incidents always occur. The second incident angle δ is δ = 180 - 3α, which is negative. The third incident angle ε is ε = 360 - 5α.

[0226] According to Figure 22(b), when the tilt angle α = 60 degrees, two incidences always occur. It can also be seen that a third incidence occurs on the triangular prism. The second incidence angle δ is δ = 180 - 3α = 0 degrees. The third incidence angle ε is ε = 360 - 5α = 60 degrees.

[0227] According to Figure 22(c), when the tilt angle α is 54 degrees < 60 degrees, a third incidence occurs depending on the incident position. The second incidence angle δ is δ = 180 - 3α. The third incidence angle ε is ε = 360 - 5α.

[0228] According to Figure 22(d), when the tilt angle α = 54 degrees, two incidences always occur. The second incidence angle δ is δ = 180 - 3α = 18 degrees. The second reflected light LB2 is parallel to the triangular prism surface. This is the limit for a third incidence.

[0229] 23(a), when the tilt angle α is 45 degrees<α<54 degrees, the third incidence does not occur depending on the incidence position. The second incidence angle δ is δ=180-3α.

[0230] 23(b), it can be seen that when the tilt angle α is 45 degrees, there is a second incidence. The second incidence angle δ is δ=45 degrees.

[0231] According to Figure 23(c), when the tilt angle α is 30 degrees < 45 degrees, a second incidence occurs depending on the incident position. The second incidence angle δ is δ = 180 - 3α. The limit position where the second incidence occurs (X C ) is defined by equation (29).

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[0232] According to FIG. 23(d), it can be seen that when the tilt angle α is 30 degrees, the second incidence does not occur.

[0233] According to FIG. 24(a), it can be seen that the second incidence does not occur even when the tilt angle α is 0 degrees<30 degrees.

[0234] FIG. 24(b) shows the results of the study. The horizontal axis represents the inclination angle α of the incident plane. The inclination angle α of the incident plane corresponds to the inclination of a pyramidal plane or the inclination of a plane forming random irregularities. The first vertical axis represents the reflectance R (graph G24a). The second vertical axis represents the scattering angle θ d (Graph G24b) is shown. The reflectance R is the average value of S-polarized light and P-polarized light. The wavelength of the light was 940 nm.

[0235] In FIG. 24(b), range R24a indicates the range of tilt angles α where the number of incidences is one. Range R24b indicates the range of tilt angles α where the number of incidences to the triangular prism is two, depending on the incidence position. Range R24c indicates the range of tilt angles α where the number of incidences is two. Range R24d indicates the range of tilt angles α where the number of incidences to the triangular prism is three, depending on the incidence position. Range R24e indicates the range of tilt angles α where the number of incidences is three.

[0236] According to graph G24b, the scattering angle θ d It was found that the scattering angle θ is approximately proportional to the inclination angle α of the incident plane. d The characteristics of showed roughly the same tendency regardless of the number of reflections considered in the analysis. The characteristics of reflectance R showed a tendency to differ depending on the number of reflections considered in the analysis. In an analysis taking into account three reflections, it was found that there is a range in which reflectance R is reduced even when the inclination angle α of the incident surface is large. It was found that the scattering angle cannot be increased for triangular prism-shaped light scattering parts and pyramid-shaped light scattering parts.

[0237] (Third Consideration) Figures 25(a) and 25(b) show the results of a simulation of a diffraction mode using plasmons in a solid-state imaging device without a DTI 22. As an analytical model, a structure was set up in which 23 silver gratings were formed on a silicon substrate with a 2 nm thick silicon oxide film interposed between them. The period of the silver grating was set to 265 nm. The width of the silver grating was set to 230 nm. The height of the silver grating was set to 180 nm. The wavelength of light was set to 940 nm.

[0238] Fig. 25(a) is a contour diagram showing the distribution of the electric field strength. More specifically, Fig. 25(a) shows the distribution of the square of the absolute value of the electric field strength. The scattering angle θ obtained by substituting the grating period of 265 nm into equation (30) is d is 80.6 degrees. The scattering angle θ obtained from Eq. (30) d The value of is the scattering angle θ d was found to be consistent with

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[0239] Figure 25(b) is a pie chart showing the destinations of the incident light L1. If the incident light L1 is taken as 100%, it was found that the proportions are as follows: 0th order reflected light (G25a): 7.7%. Scattered reflected light (G25b): 3.5%. 0th order transmitted light (G25c): 30.1%. Scattered transmitted light (G25d): 49.5%. Light absorbed by silver (G25e): 3.2%. Light absorbed by silicon (G25f): 6.1%.

[0240] The absorption in silicon is for a silicon thickness of 3 μm. From these results, it was found that the following conditions can be met: Reflectance: 11.2%. 0th order transmitted light: 30.1%. Scattering percentage: 49.5%. Main scattering angle: 80.6 degrees. The above conditions are better than those when a pyramidal scattering layer or a randomly uneven scattering layer is used as the light scattering portion.

[0241] (Fourth Consideration) Figures 26(a) and 26(b) show the results of a simulation of the diffraction mode using plasmons in a solid-state imaging device equipped with a DTI 22. As an analytical model, a structure was set up in which 23 silver gratings were formed on a silicon substrate with a 2 nm silicon oxide film interposed between them. The period of the silver grating was set to 265 nm. The width of the silver grating was set to 230 nm. The height of the silver grating was set to 180 nm. The wavelength of light was set to 940 nm.

[0242] Fig. 26(a) is a contour diagram showing the distribution of the electric field strength. More specifically, Fig. 26(a) shows the distribution of the square of the absolute value of the electric field strength.

[0243] Figure 26(b) is a pie chart showing the destinations of the incident light L1. If the incident light L1 is taken as 100%, it was found that the respective proportions are as follows. 0th order reflected light (G26a): 6.3%. Scattered reflected light (G26b): 5.9%. Transmitted light (G26c): 60.7%. Light absorbed in the trench (G26d): 2.2%. Light absorbed by silver (G26e): 3.8%. Light absorbed by silicon (G26f): 21.1%.

[0244] In Figure 26(b), the "scattered transmitted light" component shown in Figure 25(b) is included in the transmitted light (G26c). Transmitted light (G25c) indicates the sum of the proportions of the zero-order transmitted light and the scattered transmitted light. In this study, the proportion of the "light absorbed by silicon" component is increased compared to the results of the above study. When the DTI22 is provided, the proportion of the "light absorbed by silicon" component can be increased. In Figure 26(b), the increase in the "light absorbed by silicon" is part of the scattered light component.

[0245] By providing the DTI 22, the scattered transmitted light propagates repeatedly through the photoelectric conversion unit 26 due to reflection by the DTI 22. As a result, the amount of light absorbed increases. Not all light is absorbed when propagating due to reflection by the DTI 22. The light that is not absorbed is treated as transmitted light. It is included in the transmitted light (G26c).

[0246] (Fifth Consideration) FIG. 27 compares the relationship between silicon thickness and cumulative absorption amount when a plasmonic structure is provided (graph G27a) and when a plasmonic structure is not provided (graph G27b). The horizontal axis represents the silicon depth from the incident surface. The vertical axis represents the cumulative absorption ratio. In other words, the vertical axis represents the cumulative absorption amount. Graphs G27a and G27b show that the cumulative absorption amount of a solid-state imaging device with a plasmonic structure can be made greater than the cumulative absorption amount of a solid-state imaging device without a plasmonic structure.

[0247] (Fifth calculation example) Incidentally, Figure 2 of Patent Document 4 (JP 2020-13909 A) shows a cross-section of a pixel included in a back-illuminated CMOS image sensor. Figure 2 shows a light-shielding member. The light-shielding member is formed of a wiring layer. Patent Document 4 exemplifies metal wiring made of copper or aluminum as a material for the light-shielding member. Patent Document 4 also discloses that, in addition to metal materials, the light-shielding member may be made of polysilicon or an oxide film. Furthermore, Patent Document 4 discloses that the light-shielding member reflects infrared light that has passed through the semiconductor substrate without being photoelectrically converted in the semiconductor substrate, thereby allowing the infrared light to re-enter the semiconductor substrate. In other words, the light-shielding member functions to reflect in addition to blocking light. However, Patent Document 4 does not specifically disclose the cross-sectional shape of the light-shielding member. Furthermore, Patent Document 4 does not disclose that the light-shielding member scatters reflected light, nor does it disclose matters related to the angle of the reflected light.

[0248] As described in the fourth study, the solid-state imaging device 1 of the first embodiment includes a metal structure that generates diffracted light due to plasmons, and a trench. According to the pie chart in FIG. 26(b), the ratio of light G26f absorbed by silicon in the solid-state imaging device 1 of the first embodiment was 21.1%. On the other hand, according to the pie chart in FIG. 26(b), the ratio of transmitted light G26c in the solid-state imaging device 1 of the first embodiment was 60.7%. In the fourth study, the wiring portion side interface 26b of the photoelectric conversion unit 26 (FIG. 3 1 The researchers did not take into account the light reflections that occur in the

[0249] Therefore, in the fifth study, the reflection of light occurring at the wiring portion-side interface 26b of the photoelectric conversion portion 26 is taken into consideration. The analytical model used in the fifth study includes the wiring region 13. The wiring region 13 includes the wiring 18 and the via 19. However, in the fifth study, it is sufficient to simulate the reflection of light occurring at the wiring portion-side interface 26b. Therefore, the analytical model does not include the wiring 18 and the via 19.

[0250] In the fifth study, the distribution of electric field strength was calculated in the same way as in the fourth study. The values ​​used in the calculation were the same as those used in the calculation in the fourth study. In other words, as an analytical model, a structure was set up in which 23 silver gratings were formed on a silicon substrate with a 2 nm silicon oxide film in between. The period of the silver grating was set to 265 nm. The width of the silver grating was set to 230 nm. The height of the silver grating was set to 180 nm. The wavelength of the light was set to 940 nm.

[0251] Fig. 30(a) is a contour diagram showing the distribution of electric field strength. More specifically, Fig. 30(a) shows the distribution of the square of the absolute value of the electric field strength. Referring to Fig. 30(a), standing waves were also confirmed in the depth direction of the photoelectric conversion section 26. These standing waves were generated by interference between light incident from the light input surface 26a and light reflected from the wiring section side interface 26b.

[0252] Fig. 30(b) is a table summarizing the results of the fifth, sixth, seventh, and eighth studies. According to the results of the fifth study, when the incident light L1 is taken as 100%, the respective proportions are as follows. Note that due to calculation errors, even if all the proportion values ​​are added up, the total value does not equal 100%. 0th order reflected light: 43.6%. Scattered reflected light: 6.1%. Transmitted light: 19.1%. Light absorbed in the trench: 5.2%. Light absorbed by silver: 4.0%. Light absorbed by silicon: 26.6%. Total: 104.6%.

[0253] The figures from the fourth study are compared with those from the fifth study.

[0254] The results showed that the fifth study was more advantageous in terms of transmitted light than the fourth study. Specifically, the transmitted light rate for the fourth study was 60.7%, while the transmitted light rate for the fifth study was 19.1%. In other words, reflection significantly reduced the proportion of transmitted light.

[0255] The results also showed that the fifth study was more advantageous than the fourth study in terms of the amount of light absorbed by silicon. Specifically, the amount of light absorbed by silicon in the fourth study was 21.1%, while the amount of light absorbed by silicon in the fifth study was 26.6%. In other words, reflection was able to increase the proportion of light absorbed by silicon.

[0256] However, the results showed that the 0th order reflected light was less favorable in the 5th study than in the 4th study. Specifically, the 0th order reflected light in the 4th study was 6.3%, while the 0th order reflected light in the 5th study was 43.6%. In other words, it was found that the proportion of 0th order reflected light increases due to reflection.

[0257] 31 is a simplified diagram illustrating the analytical model used in the fifth study. The dashed line in FIG. 31 represents the light L3 reflected at the interface 26b on the wiring side of the photoelectric conversion section 26. of 2. Light L3 is further reflected by DTI 22. In this reflection, the angle of incidence of light L3 on DTI 22 is the same as the angle of incidence of absorbed light L2 on DTI 22 after being diffracted by light scattering unit 27. Light L3 is repeatedly reflected by DTI 22 and heads toward light input surface 26a. On its way to light input surface 26a, part of light L3 is absorbed by photoelectric conversion unit 26.

[0258] Here, it is assumed that the pair of DTIs 22 are parallel to each other and that the extension direction of the DTIs 22 is perpendicular to the light input surface 26a. Furthermore, it is assumed that the wiring portion side interface 26b is parallel to the light input surface 26a and perpendicular to the extension direction of the DTIs 22. Based on these assumptions, the angle of incidence of light L3 with respect to the light input surface 26a is the same as the angle of light L2 generated by the light scattering portion 27. When light L3 is incident on the light input surface 26a at the same angle as the angle of light L2, the action of the light scattering portion 27 causes the incident light L3 to be emitted as light L4 outside the photoelectric conversion portion 26 in the 0-degree direction. As a result, it is believed that the proportion of zero-order reflected light has increased significantly.

[0259] In summary, the fifth review revealed the following two points:

[0260] First, it was found that reflection at the wiring-side interface 26b reduces the proportion of transmitted light and increases the proportion of light absorbed by silicon. In other words, it was found that reflection at the wiring-side interface 26b contributes to an increase in the proportion of light absorbed by silicon, and is therefore beneficial to improving the photoelectric conversion efficiency of near-infrared light.

[0261] Secondly, it was found that reflection at the wiring portion side interface 26b increases the amount of light L3 emitted to the outside of the photoelectric conversion layer 401. Here, the inventors noticed that if the amount of light L3 emitted to the outside of the photoelectric conversion layer 401 could be reduced, the photoelectric conversion efficiency of near-infrared light could be further improved. In other words, the inventors realized that if the light emitted to the outside of the photoelectric conversion unit 26 could be reduced in order to further increase the proportion of light absorbed by silicon, the photoelectric conversion efficiency could be further improved.

[0262] That is, when light L3 enters light scattering section 27 from the photoelectric conversion section 26 side at the same angle as the diffraction angle of light L2 diffracted by light scattering section 27, light L3 is emitted as light L4 outside photoelectric conversion section 26 at the same angle as the angle of incidence of the original incident light. Therefore, when light L2 is reflected at wiring section side interface 26b, the reflection angle of light L3 is changed. As a result, it is possible to reduce light L4 emitted outside photoelectric conversion section 26 made of silicon.

[0263] For example, a configuration for changing the reflection angle of light L3 at the wiring portion side interface 26b may be provided to change the reflection angle of light L3 to an angle different from the incident angle. A solid-state imaging device having such a configuration will be described as a second embodiment. Furthermore, a scattering structure may be provided at the wiring portion side interface 26b to change the reflection angle of light L3. A solid-state imaging device having such a configuration will be described as a third embodiment.

[0264] Second Embodiment Fig. 32(a) is a cross-sectional view showing the structure of a solid-state imaging device 11 according to the second embodiment. Fig. 32(b) is a perspective view showing an interface 411 on the wiring layer side of a photoelectric conversion layer 401 included in the solid-state imaging device 11.

[0265] The solid-state imaging device 11 includes an incident-side insulating layer 60, a photoelectric conversion layer 401, and a wiring layer 501.

[0266] The incident-side insulating layer 60 is made of, for example, silicon oxide (SiO2). The incident-side insulating layer 60 has an incident-side insulating layer main surface 61 and an incident-side insulating layer back surface 62. The incident-side insulating layer main surface 61 receives light. In other words, the incident-side insulating layer main surface 61 is the light input surface of the solid-state imaging device 11. The incident-side insulating layer back surface 62 contacts the photoelectric conversion layer 401. Light scattering portions 27 are embedded in the incident-side insulating layer 60. The details of the light scattering portions 27 are the same as those of the light scattering portions 27 in the first embodiment.

[0267] The photoelectric conversion layer 401 is mainly composed of silicon (Si). Details of the photoelectric conversion layer 401 are approximately the same as those of the photoelectric conversion layer 401 of the first embodiment. In the photoelectric conversion layer 401 of the second embodiment, explanations of the configurations that are the same as those of the photoelectric conversion layer 401 of the first embodiment will be omitted, and configurations that differ from those of the photoelectric conversion layer 401 of the first embodiment will be explained in detail.

[0268] The photoelectric conversion layer 401 has a wiring layer side interface 411 (photoelectric conversion back surface, second photoelectric conversion interface), an insulating layer side interface 42 (photoelectric conversion main surface, first photoelectric conversion interface), and a DTI side interface 43. The insulating layer side interface 42 of the photoelectric conversion layer 401 contacts the incident-side insulating layer back surface 62 of the incident-side insulating layer 60. A light scattering portion 27 is provided at the insulating layer side interface 42. The wiring layer side interface 411 contacts the wiring layer 501. The distance from the insulating layer side interface 42 to the wiring layer side interface 411 is, for example, 3 μm. In other words, the distance from the insulating layer side interface 42 to the wiring layer side interface 411 is the thickness of the photoelectric conversion layer 401.

[0269] The photoelectric conversion layer 401 is provided with a DTI 22. Details of the DTI 22 of the second embodiment are the same as those of the DTI 22 of the first embodiment. A DTI-side interface 43 of the photoelectric conversion layer 401 contacts the DTI side surface 221 of the DTI 22.

[0270] The wiring layer 501 is made of, for example, silicon oxide (SiO2). Details of the wiring layer 501 of the second embodiment are approximately the same as those of the wiring layer 501 of the first embodiment. In the wiring layer 501 of the second embodiment, descriptions of the same configuration as the wiring layer 501 of the first embodiment will be omitted, and configurations not described in the first embodiment will be described in detail.

[0271] The wiring layer 501 has a wiring layer main surface 511. The wiring layer main surface 511 contacts the wiring layer side interface 411 of the photoelectric conversion layer 401.

[0272] Here, a detailed description will be given of a characteristic configuration of the solid-state imaging device 11 of the second embodiment. In the solid-state imaging device 11 of the second embodiment, the shape of the wiring layer side interface 411 is different from the shape of the wiring portion side interface 26b of the first embodiment.

[0273] 31, the wiring portion-side interface 26b of the photoelectric conversion unit 26 of the solid-state imaging device 1 of the first embodiment is a flat surface. Furthermore, the wiring portion-side interface 26b is perpendicular to the thickness direction of the photoelectric conversion unit 26. In other words, the wiring portion-side interface 26b is perpendicular to the DTI-side interface 26c.

[0274] As shown in FIG. 32A, the wiring layer side interface 411 of the solid-state imaging device 11 of the second embodiment includes a first interface 41a1 and a second interface 41b1. The first interface 41a1 contacts the first main surface 51a1 of the wiring layer main surface 511. The second interface 41b1 contacts the second main surface 51b1 of the wiring layer main surface 511. The first interface 41a1 and the second interface 41b1 are each flat. On the other hand, the first interface 41a1 and the second interface 41b1 are not orthogonal to the thickness direction of the photoelectric conversion layer 401. In other words, the first interface 41a1 and the second interface 41b1 are inclined surfaces inclined with respect to the thickness direction of the photoelectric conversion layer 401. For example, a virtual plane K connecting the lower ends of the DTIs 22 is defined. When the imaginary plane K is used as a reference, the angle of the first interface portion 41a1 with respect to the imaginary plane K is 5 degrees. Similarly, the angle of the second interface portion 41b1 with respect to the imaginary plane K is also 5 degrees. The angle of the first interface portion 41a1 may be the same as or different from that of the second interface portion 41b1.

[0275] The ridge line 41c1, which is the boundary between the first interface portion 41a1 and the second interface portion 41b1, is located approximately in the center of the width of the photoelectric conversion layer 401. The width of the photoelectric conversion layer 401 is the distance from one DTI-side interface 43 to the other DTI-side interface 43. The width of the photoelectric conversion layer 401 can also be said to be the distance from one DTI 22 to the other DTI 22. Furthermore, the ridge line 41c1 is located closer to the wiring layer 501 than the lower end surfaces of the DTI 22. In other words, the ridge line 41c1 is located outside between the pair of DTIs 22. In other words, the wiring layer-side interface 411 of the photoelectric conversion layer 401 protrudes toward the wiring layer 501.

[0276] In a cross section of the photoelectric conversion layer 401, a cross-sectional area A1 formed by the imaginary plane K, the first interface 41a1, and the second interface 41b1 can be referred to as a "light-direction changing portion 301." The first interface 41a1 and the second interface 41b1 can also be referred to as the surface of the light-direction changing portion 301. The solid-state imaging device 1 of the first embodiment shown in FIG. 31 does not include a portion corresponding to the light-direction changing portion 301 included in the solid-state imaging device 11 of the second embodiment. In other words, it can be said that the light-direction changing portion 301 is a portion of the photoelectric conversion layer 401 that is different from the photoelectric conversion portion 26 of the solid-state imaging device 1 of the first embodiment.

[0277] Fig. 32(b) is a perspective view of the wiring layer side interface 411 of the photoelectric conversion layer 401. As shown in Fig. 32(b), the wiring layer side interface 411 of the photoelectric conversion layer 401 is a swept body obtained by sweeping the cross-sectional area A1 along a predetermined axis X.

[0278] FIG. 33 schematically illustrates how light travels within the photoelectric conversion layer 401 of the solid-state imaging device 11 of the second embodiment. The light scattering section 27 receives light L1 and emits light L2. The traveling direction of light L2 is at an angle (θ) with reference axis D1, which is the normal direction of the insulating layer-side interface 42. The light L2 is reflected at the DTI-side interface 43. At this time, the angle of incidence of light L2 with respect to the DTI-side interface 43 is (90-θ) degrees. The angle of reflection is also (90-θ) degrees. The light L2 is reflected multiple times at the DTI-side interface 43 and reaches the wiring layer-side interface 411. The angle (φ) of the wiring layer-side interface 411 is defined based on axis D2, which is orthogonal to the reference axis D. The angle of incidence of light L2 with respect to the wiring layer-side interface 411 is then (θ-φ) degrees.

[0279] Here, the wiring portion side interface 26b in the first embodiment is a flat surface. 、 φ=0 degrees. On the other hand, the wiring layer side interface 411 of the second embodiment is an inclined surface. For example, φ=5 degrees. Therefore, it can be said that the angle of incidence at the wiring layer side interface 411 of the second embodiment is changed by φ degrees compared to the angle of incidence at the wiring portion side interface 26b of the first embodiment. As a result, the angle of incidence when the light L3 is incident again on the light scattering portion 27 is (θ −2φ) degrees. That is, the angle of incidence (θ−2φ) of light L3 when it enters light scattering section 27 is different from the angle (θ) of light L2. As a result, the state of diffraction in light scattering section 27 changes from that in the case of incidence, and emission of light L3 from photoelectric conversion layer 401 to the outside is suppressed.

[0280] (Sixth Consideration) As a sixth study, the distribution of the electric field intensity was obtained for the solid-state imaging device 11 of the second embodiment in the same manner as in the fifth study. The values ​​used in the calculation are as follows. Angle of the wiring portion side interface 411: 5 degrees. Pixel size: 6.5 μm. The thickness of the photoelectric conversion layer 401 is 3 μm. Wiring layer thickness: 4.1 μm. The thickness of the photoelectric conversion layer 401 and the thickness of the wiring layer 501 are values ​​in the vicinity of the DTI 22.

[0281] FIG. 34 is a contour diagram showing the distribution of electric field intensity. More specifically, FIG. 34 shows the distribution of the square of the absolute value of the electric field intensity. Referring to FIG. 34, similar to the results of the fifth study (FIG. 30(a)), standing waves were also confirmed in the depth direction of the photoelectric conversion section 26. A detailed comparison revealed that the standing waves in the sixth study were more disturbed than those in the fifth study. This disturbance in the standing wave is thought to be caused by a change in the reflection angle due to the inclination of the wiring section side interface 411.

[0282] According to the results of the sixth study shown in FIG. 30(b), when the incident light L1 is taken as 100%, it was found that the respective proportions are as follows. 0th order reflected light: 33.8%. Scattered reflected light: 6.5%. Transmitted light: 14.5%. Light absorbed in the trench: 7.2%. Light absorbed by silver: 2.9%. Light absorbed by silicon: 38.1%. Total: 103.0%.

[0283] The figures from the fifth study are compared with those from the sixth study.

[0284] The results showed that the sixth study was more advantageous than the fifth study in terms of zero-order reflected light. Specifically, the zero-order reflected light in the fifth study was 43.6%. On the other hand, the zero-order reflected light in the sixth study was 33.8%. In other words, by tilting the wiring portion side interface 411, the proportion of zero-order reflected light could be reduced.

[0285] The results also showed that the sixth study was more advantageous than the fifth study in terms of transmitted light. Specifically, the transmitted light in the fifth study was 19.1%. On the other hand, the transmitted light in the sixth study was 14.5%. In other words, by tilting the wiring portion side interface 411, the proportion of zero-order reflected light could be reduced.

[0286] The results also showed that the sixth study was more advantageous than the fifth study in terms of the amount of light absorbed by silicon. Specifically, the amount of light absorbed by silicon in the fifth study was 26.6%. On the other hand, the amount of light absorbed by silicon in the sixth study was 38.1%. In other words, by tilting the interface 411 on the wiring portion side, , Shi This allowed us to increase the proportion of light absorbed by the silicon.

[0287] Therefore, it was found that the inclination of the wiring portion side interface 411 suppresses the emission of light from the photoelectric conversion layer 401. As a result, it was found that the photoelectric conversion efficiency of near-infrared light can be further improved.

[0288] <Modification of the second embodiment> In the solid-state imaging device 11 of the second embodiment, the direction of the redirected light L3 is based on the direction of the light L2 before the redirection. This configuration is known as specular reflection. The shape of the light-direction changing unit 301 may be any shape that produces specular reflection, and is not limited to the shape of the solid-state imaging device 11 of the second embodiment.

[0289] Modifications 1, 2, and 3 of the second embodiment are examples of the wiring layer side interface formed by a flat surface.

[0290] <Modification 1 of the Second Embodiment> FIG. 35(a) is a cross-sectional view showing the structure of a solid-state imaging device 12 according to Modification 1 of the second embodiment. FIG. 35(b) is a perspective view showing a wiring layer-side interface 412 of a photoelectric conversion layer 402 included in the solid-state imaging device 12. The light-direction changing portion 302 may have a shape of a quadrangular pyramid. One side of the quadrangular pyramid may be the same as the spacing between the DTIs 22. The wiring layer-side interface 412 includes a first interface 41a2, a second interface 41b2, a third interface 41c2, and a fourth interface 41d2. The first interface 41a2 contacts the first main surface 51a2 of the wiring layer main surface 512. The second interface 41b2 contacts the second main surface 51b2 of the wiring layer main surface 512. The third interface 41c2 contacts the third main surface of the wiring layer main surface 512. The fourth interface portion 41d2 contacts the fourth main surface portion of the wiring layer main surface 512. The vertex 41p2 is located closer to the wiring layer 502 than the imaginary plane K. The vertex 41p2 is located outside the gap between the pair of DTIs 22. That is, the light direction changing portion 302 has a protrusion shape.

[0291] <Modification 2 of the Second Embodiment> FIG. 36(a) is a cross-sectional view showing the structure of a solid-state imaging device 13 according to Modification 2 of the second embodiment. FIG. 36(b) is a perspective view showing a wiring layer side interface 413 of a photoelectric conversion layer 403 included in the solid-state imaging device 13. The light direction changing portion 303 is recessed with respect to the imaginary plane K. While the light direction changing portion 301 of the second embodiment is a protrusion, the light direction changing portion 303 is a recess. The light direction changing portion 303 includes a first interface portion 41a3 and a second interface portion 41b3. The first interface portion 41a3 is in contact with the first main surface portion 51a3 of the wiring layer main surface 513. The second interface portion 41b3 is in contact with the second main surface portion 51b3 of the wiring layer main surface 513. The ridge line 41c3 is located between a pair of DTIs 22.

[0292] <Modification 3 of the Second Embodiment> FIG. 37(a) is a cross-sectional view showing the structure of a solid-state imaging device 14 according to Modification 3 of the second embodiment. FIG. 37(b) is a perspective view showing a wiring layer-side interface 414 of a photoelectric conversion layer 404 included in the solid-state imaging device 14. The light-direction-changing portion 304 may have a quadrangular pyramid shape. While the light-direction-changing portion 302 according to Modification 1 of the second embodiment is a protrusion, the light-direction-changing portion 304 according to Modification 3 of the second embodiment is a recess. The wiring layer-side interface 414 of the photoelectric conversion layer 404 includes a first interface 41a4, a second interface 41b4, a third interface 41c4, and a fourth interface 41d4. The first interface 41a4 is in contact with the first main surface 51a4 of the wiring layer main surface 514. The second interface 41b4 is in contact with the second main surface 51b4 of the wiring layer main surface 514. The third interface portion 41c4 contacts the third main surface portion of the wiring layer main surface 514. The fourth interface portion 41d4 contacts the fourth main surface portion of the wiring layer main surface 514. The vertex 41p4 is located between the pair of DTIs 22. That is, the light direction changing portion 304 is a recessed portion.

[0293] The wiring layer side interface 411 and the like in the second embodiment described above are configured with several flat surfaces. The wiring layer side interface may include a curved portion. Modifications 4, 5, 6, and 7 of the second embodiment are examples of wiring layer side interfaces that include a curved portion.

[0294] <Fourth Modification of the Second Embodiment> FIG. 38(a) is a cross-sectional view showing the structure of a solid-state imaging device 15 according to Modification 4 of the second embodiment. FIG. 38(b) is a perspective view showing the wiring layer side interface 415 of the photoelectric conversion layer 405 included in the solid-state imaging device 15. The cross section of the wiring layer side interface 415 of the photoelectric conversion layer 405 may be elliptical. An area A5 surrounded by the imaginary plane K and the curved surface 41s5 corresponds to the light-direction changing unit 305. The curved surface 41s5 protrudes from the imaginary plane K toward the wiring layer 505. The curved surface 41s5 is in contact with the curved surface 51s5 of the wiring layer main surface 515. The curved surface 41s5 extends from one DTI-side interface 43 to the other DTI-side interface 43. In other words, the portion of the wiring layer side interface 415 between the DTI-side interfaces 43 does not include a flat surface. There are no particular limitations on the shape of the curved surface 41s5. For example, the curve appearing in the cross section of the curved surface 41s5 may be a quadratic curve such as an ellipse, a hyperbola, or a parabola. The wiring layer side interface 415 of the photoelectric conversion layer 405 is a swept body obtained by sweeping, along a predetermined axis X, a cross-sectional area A5 surrounded by a line included in the imaginary plane K and a curve included in the curved surface 41s5.

[0295] <Fifth Modification of the Second Embodiment> FIG. 39(a) is a cross-sectional view showing the structure of a solid-state imaging device 16 according to Modification 5 of the second embodiment. FIG. 39(b) is a perspective view showing a wiring layer side interface 416 of a photoelectric conversion layer 406 included in the solid-state imaging device 16. The cross section of the wiring layer side interface 416 of the photoelectric conversion layer 406 includes an elliptical portion. The light direction changer 305 according to Modification 4 of the second embodiment (see FIG. 38(b)) is a swept body in which the cross-sectional area A5 is swept in the direction of a predetermined axis X. The light direction changer 306 according to Modification 5 of the second embodiment is a rotated body in which the cross-sectional area A6 is rotated around a predetermined axis Z. For example, the light direction changer 306 has a shape similar to a convex lens. The light direction changer 306 includes a curved surface 41s6. The curved surface 41s6 is in contact with the curved surface 51s6 of the wiring layer main surface 516. The light direction changer 306 protrudes toward the wiring layer 506 side.

[0296] <Sixth Modification of the Second Embodiment> FIG. 40(a) is a cross-sectional view showing the structure of a solid-state imaging device 17 according to Modification 6 of the second embodiment. FIG. 40(b) is a perspective view showing a wiring layer side interface 417 of a photoelectric conversion layer 407 included in the solid-state imaging device 17. The light direction changer 307 is recessed with respect to the imaginary plane K. That is, while the light direction changer 305 in Modification 4 of the second embodiment is a protrusion (FIG. 38(b)), the light direction changer 307 is a recess. The light direction changer 307 includes a curved surface 41s7. The curved surface 41s7, which is the surface of the light direction changer 307, is a swept surface obtained by sweeping the cross-sectional area A7 in the direction of a predetermined axis X. The curved surface 41s7 is in contact with a curved surface 51s7 of the wiring layer main surface 517. The curved surface 41s7 is located between a pair of DTIs 22.

[0297] <Seventh Modification of the Second Embodiment> FIG. 41(a) is a cross-sectional view showing the structure of a solid-state imaging device 18 according to Modification 7 of the second embodiment. FIG. 41(b) is a perspective view showing a wiring layer side interface 418 of a photoelectric conversion layer 408 included in the solid-state imaging device 18. The light direction changing portion 308 is recessed with respect to the imaginary plane K. The curved surface 41s8, which is the surface of the light direction changing portion 308, is a surface of revolution obtained by rotating the cross-sectional area A8 around a predetermined axis Z. For example, the light direction changing portion 308 has a shape similar to a concave lens. The curved surface 41s8 is in contact with the curved surface 51s8 of the wiring layer main surface 518. The curved surface 41s7 is located between a pair of DTIs 22.

[0298] As already mentioned, a scattering structure may be provided at the interface on the wiring layer side as a configuration for changing the reflection angle of light L3. A solid-state imaging device in which a light scattering structure is provided at the interface on the wiring layer side will be described as a third embodiment.

[0299] Third Embodiment Fig. 42(a) is a cross-sectional view showing the structure of a solid-state imaging device 19 according to the third embodiment. Fig. 42(b) is a perspective view showing an interface 419 on the wiring layer side of a photoelectric conversion layer 409 included in the solid-state imaging device 19.

[0300] The wiring layer side interface 419 has an interface recess 41a9 and an interface flat portion 41b9. The interface flat portion 41b9 is perpendicular to the DTI side interface 43. The interface recess 41a9 is recessed further than the interface flat portion 41b9. The interface recess 41a9 is provided between a pair of DTIs 22. The distance from the interface recess 41a9 to one of the DTIs 22 is approximately the same as the distance from the interface recess 41a9 to the other DTI 22. The interface recess 41a9 is provided approximately in the center of the wiring layer side interface 419 surrounded by the DTIs 22.

[0301] The depth of the interface recess 41a9 can be defined with reference to the interface flat portion 41b9. The depth of the interface recess 41a9 is the distance from the interface flat portion 41b9 to the recess bottom surface 41t9 of the interface recess 41a9. A wiring layer protrusion 51t9 protruding from the wiring layer main surface 519 of the wiring layer 509 is disposed in the interface recess 41a9. The upper surface of the wiring layer protrusion 51t9 is in contact with the recess bottom surface 41t9 of the interface recess 41a9. Therefore, the depth of the interface recess 41a9 is the same as the height of the wiring layer protrusion 51t9.

[0302] The depth of the interface recess 41a9 is determined based on the wavelength of the light L2. For example, the depth of the interface recess 41a9 is longer than 10% of the wavelength (λ) of the light L2. This definition can also be said to be the lower limit of the depth of the interface recess 41a9. Furthermore, the depth of the interface recess 41a9 is shorter than five times the wavelength (λ) of the light L2. This definition can also be said to be the upper limit of the depth of the interface recess 41a9.

[0303] The wavelength (λ) of light L2 here is a value based on the refractive index of the photoelectric conversion layer 409. For example, assume that the refractive index of light L2 in a vacuum is 940 nm. The main material of the photoelectric conversion layer 409 is silicon. The real part of the refractive index of silicon is 3.59. Therefore, the wavelength of light L2 in silicon is 262 nm.

[0304] The depth of interface recess 41a9 may be, for example, 1 / 10 or more of 262 nm. The depth of interface recess 41a9 may be, for example, less than 5 times 262 nm. As an example, the depth of interface recess 41a9 may be 405 nm. In this case, the depth of interface recess 41a9 (405 nm) is approximately 1.55 times the wavelength (262 nm). The width of interface recess 41a9 may be, for example, 285 nm.

[0305] When metal structures 27a and interface recess 41a9 of light scattering section 27 are viewed in plan, interface recess 41a9 may entirely overlap with metal structures 27a. A part of interface recess 41a9 may overlap with metal structures 27a, and another part may not overlap with metal structures 27a. In other words, another part of interface recess 41a9 may overlap with a gap between adjacent metal structures 27a. Furthermore, interface recess 41a9 may not entirely overlap with metal structures 27a. In other words, interface recess 41a9 may entirely overlap with a gap between adjacent metal structures 27a.

[0306] 43 schematically shows how light travels inside the photoelectric conversion layer 409 of the solid-state imaging device 19 of the third embodiment. The light scattering portion 27 receives light L1 and emits light L2. The traveling direction of light L2 is at an angle (θ) with the normal direction of the insulating layer-side interface 42 as a reference axis D1. After being reflected multiple times at the DTI-side interface 43, light L2 is incident on the interface recess 41a9 of the wiring layer-side interface 419.

[0307] The interface recess 41a9, upon which the light L2 is incident, emits scattered light L3S. The direction of the light L3S is distributed around the interface recess 41a9. This scattering changes the traveling direction of the light. Therefore, the interface recess 41a9 is a light direction changer. The light L3S that is incident again on the light scattering section 27 includes a component that is incident on the light scattering section 27 at an incident angle different from the angle (θ) of the light L2. As a result, the state of diffraction at the light scattering section 27 changes from that in the case of incidence, and the emission of the light L3S from the photoelectric conversion layer 409 to the outside is suppressed.

[0308] Therefore, the interface recesses 41a9 can also be said to be light scatterers. The solid-state imaging device 19 of the third embodiment has a light scattering portion 27 provided at the insulating layer side interface 42 and a scatterer that is the interface recesses 41a9 provided at the wiring layer side interface 419. In other words, the solid-state imaging device 19 of the third embodiment has the function of scattering two types of light. The scattering provided by the light scattering portion 27 increases the angle of incidence on the photoelectric conversion layer 409. The scattering provided by the interface recesses 41a9 causes the angle of incidence of light traveling through the photoelectric conversion layer 409 when it re-enters the light scattering portion 27 to differ from the diffraction angle.

[0309] <Modification of the third embodiment> The shape of the light direction changing portion 301 is not limited to the shape of the solid-state imaging device 19 of the third embodiment, as long as it scatters light.

[0310] <Modification 1 of the Third Embodiment> FIG. 44(a) shows a solid-state imaging device 1 according to a first modification of the third embodiment. 10 FIG. 44(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 10 Photoelectric conversion layer 40 10 The wiring layer side interface 41 10 The interface recess 41a is a perspective view showing the interface recess 41a. 10 The wiring layer side interface 41 10 A plurality of interface recesses 41a may be provided. 10 is a light direction change unit 30 10 The interface recess 41a 10 The shape of the single interface recess 41a may be the same as the interface recess 41a9 of the third embodiment. 10 A plurality of interface recesses 41a are provided along the X-axis direction. 10 are provided along the Y-axis direction perpendicular to the X-axis. 10 are arranged in a lattice pattern. 10 The intervals between the interface recesses 41a may be the same. 10 The interface recesses 41a may be regularly arranged. 10 The intervals between the interface recesses 41a may be different from each other.10 may be irregularly arranged.

[0311] <Modification 2 of the Third Embodiment> FIG. 45(a) shows a solid-state imaging device 1 according to a second modification of the third embodiment. 11 FIG. 45(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 11 Photoelectric conversion layer 40 11 The wiring layer side interface 41 11 FIG. 10 is a perspective view showing a solid-state imaging device 1 according to a second modification of the third embodiment. 11 is one interface recess 41a 11 One interface recess 41a 11 is a light direction change unit 30 11 For example, the interface recess 41a9 of the third embodiment is square in plan view. 11 In other words, the interface recess 41a is rectangular in plan view. 11 The interfacial recess 41a has a stripe shape. The long side is longer than the short side. 11 The interface recess 41a may extend from one DTI 22 to the other DTI 22. 11 The depth of the recess 41a may be the same as that of the interface recess 41a9 in the third embodiment.

[0312] (Seventh Consideration) In the seventh study, the solid-state imaging device 1 of the second modification 11 The effect of the structure of the interface recess 41a, which is a light direction changer, was confirmed. 11 The depth was set to 405 nm and the width was set to 285 nm. According to the results of the seventh study shown in Figure 30(b), when light L1 is set to 100%, the respective proportions are as follows. 0th order reflected light: 10.2%. Scattered reflected light: 4.7%. Transmitted light: 20.2%. Light absorbed in the trench: 8.9%. Light absorbed by silver: 12.1%. Light absorbed by silicon: 42.1%. Total: 98.1%.

[0313] The figures from the fifth study are compared with those from the seventh study.

[0314] The results show that the seventh study is more advantageous than the fifth study in terms of the zero-order reflected light. Specifically, the zero-order reflected light in the fifth study was 43.6%. On the other hand, the zero-order reflected light in the seventh study was 10.2%. In other words, the interface recess 41a, which is a scattering body, 11 By providing this, the proportion of the zero-order reflected light could be reduced.

[0315] The results show that the seventh study is more advantageous than the fifth study in terms of the amount of light absorbed by silicon. Specifically, the amount of light absorbed by silicon in the fifth study was 26.6%. On the other hand, the amount of light absorbed by silicon in the seventh study was 42.0%. In other words, the interfacial recess 41a, which is a scatterer, 11 By providing the silicon, the proportion of light absorbed by the silicon could be increased.

[0316] Regarding transmitted light, no significant difference was observed between the results of the fifth and seventh studies.

[0317] As a result of comparing the fifth study with the seventh study, the interface recess 41a, which is a light scattering body, 11 According to the results, it was found that light can be emitted at an angle different from the angle of reflection at the interface 26b on the wiring portion side, which is a flat surface.

[0318] <Modification 3 of the Third Embodiment> FIG. 46(a) shows a solid-state imaging device 1 according to a third modification of the third embodiment. 12 FIG. 46(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 12 Photoelectric conversion layer 40 12 The wiring layer side interface 41 12 FIG. 10 is a perspective view showing a solid-state imaging device 1 according to a third modification of the third embodiment. 12 The recessed portions 41a 12 The plurality of interface recesses 41a 12 is a light direction change unit 3012 The interface recess 41a 12 The shape of the single unit is the same as the interface recess 41a of the modified example 2 of the third embodiment. 11 The plurality of interface recesses 41a may be the same as the plurality of interface recesses 41a. 12 is the interface recess 41a 12 are spaced apart from each other along a second direction perpendicular to the first direction in which they extend.

[0319] (Eighth Consideration) In the eighth study, the solid-state imaging device 1 of the third modification 12 The effect of the structure of the interface recess 41a, which is a light direction changer, was confirmed. 12 The depth of the interface recess 41a was 405 nm and the width was 285 nm. 12 The number of these is 23. According to the results of the eighth study shown in FIG. 30(b), when the incident light L1 is taken as 100%, it was found that the respective proportions are as follows. 0th order reflected light: 27.6%. Scattered reflected light: 3.4%. Transmitted light: 17.5%. Light absorbed in the trench: 7.0%. Light absorbed by silver: 12.3%. Light absorbed by silicon: 30.8%. Total: 98.6%.

[0320] The figures from the fifth study are compared with those from the eighth study.

[0321] The results show that the seventh study is more advantageous than the fifth study in terms of the zero-order reflected light. Specifically, the zero-order reflected light in the fifth study was 43.6%. On the other hand, the zero-order reflected light in the eighth study was 27.7%. In other words, the interface recess 41a, which is a scatterer, 12 By providing this, the proportion of the zero-order reflected light could be reduced.

[0322] The results show that the eighth study is more advantageous than the fifth study in terms of transmitted light. Specifically, the fifth study's transmitted light was 19.1%. On the other hand, the eighth study's transmitted light was 17.5%. In other words, the interface recess 41a, which is a scattering body, 12 By providing the above, the proportion of transmitted light could be reduced.

[0323] The results show that the eighth study is more advantageous than the fifth study in terms of the amount of light absorbed by silicon. Specifically, the fifth study absorbed 26.6% of the light. On the other hand, the eighth study absorbed 30.8% of the light. In other words, the interfacial recess 41a, which is a scatterer, 12 By providing the silicon, the proportion of light absorbed by the silicon could be increased.

[0324] <Fourth Modification of the Third Embodiment> FIG. 47(a) shows a solid-state imaging device 1 according to a fourth modification of the third embodiment. 13 FIG. 47(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 13 Photoelectric conversion layer 40 13 The wiring layer side interface 41 13 The interface recess 41a9 of the third embodiment has a rectangular parallelepiped shape. The shape of the interface recess 41a9 is not limited to a rectangular parallelepiped. For example, the interface recess 41a9 of the fourth modification of the third embodiment has a rectangular parallelepiped shape. 13 The shape of the interface recess 41a is a quadrangular pyramid. 13 When the shape of the interface recess 41a is a quadrangular pyramid, 13 The cross-sectional shape of the solid-state imaging device 1 according to the fourth modification of the third embodiment is a triangle. 13 is one interface recess 41a 13 One interface recess 41a 13 is a light direction change unit 30 13 The interface recess 41a 13 Like the interface recess 41a9, the interface recess 41a is provided in the approximate center of the area surrounded by the DTI 22. 13 The depth of the interface recess 41a9 may be the same as the width of the interface recess 41a9. 13The length of the bottom side of the recess 41a9 may also be the same as the width of the recess 41a9.

[0325] <Fifth Modification of the Third Embodiment> FIG. 48(a) shows a solid-state imaging device 1 according to a fifth modification of the third embodiment. 14 FIG. 48(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 14 Photoelectric conversion layer 40 14 The wiring layer side interface 41 14 The interface recess 41a is a perspective view showing the interface recess 41a. 14 The wiring layer side interface 41 14 A plurality of interface recesses 41a may be provided. 14 is a light direction change unit 30 14 The interface recess 41a 14 The shape of the single unit is the same as the interface recess 41a of the third modification of the third embodiment. 12 The plurality of interface recesses 41a may be the same as the plurality of interface recesses 41a. 14 A plurality of interface recesses 41a are provided along the X-axis direction. 14 In other words, a plurality of interface recesses 41a are provided along the Y-axis direction. 14 are arranged in a grid pattern.

[0326] <Sixth Modification of the Third Embodiment> FIG. 49(a) shows a solid-state imaging device 1 according to a sixth modification of the third embodiment. 15 FIG. 49(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 15 Photoelectric conversion layer 40 15 The wiring layer side interface 41 15 1 is a perspective view showing the solid-state imaging device 1. 15 is one interface recess 41a 15 One interface recess 41a 15 is a light direction change unit 30 15 Solid-state imaging device 1 15 The interface recess 41a 15 The interfacial recess 41a has a stripe shape with a triangular cross section. 15 Also, the interface recess 41a of the second modification of the third embodiment 11Similarly, it may extend from one DTI 22 to the other DTI 22.

[0327] <Seventh Modification of the Third Embodiment> FIG. 50(a) shows a solid-state imaging device 1 according to a seventh modification of the third embodiment. 16 FIG. 50(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 16 Photoelectric conversion layer 40 16 The wiring layer side interface 41 16 The interface recess 41a is a perspective view showing the interface recess 41a. 16 The wiring layer side interface 41 16 A plurality of interface recesses 41a may be provided. 16 is a light direction change unit 30 16 The interface recess 41a 16 The shape of the single unit is the same as the interface recess 41a of the sixth modified example of the third embodiment. 15 The plurality of interface recesses 41a may be the same as the plurality of interface recesses 41a. 16 is the interface recess 41a 16 are spaced apart from each other along another direction perpendicular to the direction in which the

[0328] <Eighth Modification of the Third Embodiment> FIG. 51(a) shows a solid-state imaging device 1 according to Modification 8 of the third embodiment. 17 FIG. 51(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 17 Photoelectric conversion layer 40 17 The wiring layer side interface 41 17 The interface recess 41a9 of the third embodiment has a rectangular parallelepiped shape. The shape of the interface recess 41a9 is not limited to a rectangular parallelepiped. For example, the interface recess 41a9 of the eighth modified example of the third embodiment has a rectangular parallelepiped shape. 17 The shape of the interface recess 41a includes a curved surface. 17 When the shape of the interface recess 41a is a curved surface, 17 The cross-sectional shape of the interface recess 41a includes a circular arc. 17 The cross-sectional shape of the solid-state imaging device 1 according to the eighth modification of the third embodiment is a part of an ellipse. 17 is one interface recess 41a 17 One interface recess 41a 17 is a light direction change unit 3017 The interface recess 41a 17 Like the interface recess 41a9, the interface recess 41a is provided in the approximate center of the area surrounded by the DTI 22. 17 The depth of the interface recess 41a may be the same as the depth of the interface recess 41a9. 17 The diameter of the recess 41a9 may also be the same as the width of the recess 41a9.

[0329] <Modification 9 of the Third Embodiment> FIG. 52(a) shows a solid-state imaging device 1 according to a ninth modification of the third embodiment. 18 FIG. 52(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 18 Photoelectric conversion layer 40 18 The wiring layer side interface 41 18 The interface recess 41a is a perspective view showing the interface recess 41a. 18 The wiring layer side interface 41 18 A plurality of interface recesses 41a may be provided. 18 is a light direction change unit 30 18 The interface recess 41a 18 The shape of the single unit is the same as the interface recess 41a of the modified example 8 of the third embodiment. 16 The plurality of interface recesses 41a may be the same as the plurality of interface recesses 41a. 18 A plurality of interface recesses 41a are provided along the X-axis direction. 18 In other words, a plurality of interface recesses 41a are provided along the Y-axis direction. 18 are arranged in a grid pattern.

[0330] <Modification 10 of the Third Embodiment> FIG. 53(a) shows a solid-state imaging device 1 according to a tenth modification of the third embodiment. 19 FIG. 53(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 19 Photoelectric conversion layer 40 19 The wiring layer side interface 41 19 1 is a perspective view showing the solid-state imaging device 1. 19 is one interface recess 41a 19 One interface recess 41a 19 is a light direction change unit 30 19 Solid-state imaging device 119 The interface recess 41a 19 The cross section of the interface recess 41a is an ellipse. 19 corresponds to the surface of the sweep body extending in a predetermined direction. 19 The interfacial recess 41a is striped. 19 The DTI 22 may also extend from one DTI 22 to the other DTI 22.

[0331] <Eleventh Modification of Third Embodiment> FIG. 54(a) shows a solid-state imaging device 1 according to an eleventh modification of the third embodiment. 20 FIG. 54(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 20 Photoelectric conversion layer 40 20 The wiring layer side interface 41 20 The interface recess 41a is a perspective view showing the interface recess 41a. 20 The wiring layer side interface 41 20 A plurality of interface recesses 41a may be provided. 20 is a light direction change unit 30 20 The interface recess 41a 20 The shape of the single unit is the same as the interface recess 41a of the modified example 10 of the third embodiment. 19 The plurality of interface recesses 41a may be the same as the plurality of interface recesses 41a. 20 is the interface recess 41a 20 are spaced apart from each other along another direction perpendicular to the direction in which the

[0332] In the third embodiment, light direction changing portions 309 and the like are recesses recessed from interfacial flat portion 41b9. Light direction changing portions that are light scatterers may be convex portions that protrude from interfacial flat portion 41b9. Examples in which light direction changing portions are convex portions will be described below as Modifications 12 to 23 of the third embodiment.

[0333] <Modification 12 of the Third Embodiment> FIG. 55(a) shows a solid-state imaging device 1 according to a twelfth modification of the third embodiment. 21 FIG. 55(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 21 Photoelectric conversion layer 40 21 The wiring layer side interface 41 211 is a perspective view showing the wiring layer side interface 41. 21 The interface protrusion 41a 21 and the interface flat portion 41b 21 and a solid-state imaging device 1. 21 is one interface protrusion 41a 21 One interface protrusion 41a 21 is a light direction change unit 30 21 The interface protrusion 41a 21 is the wiring layer 50 21 The interface protrusion 41a protrudes to the side. 21 is the wiring layer 50 21 The wiring layer main surface 51 21 The wiring layer recess 51t recessed from the 21 The interface protrusions 41a are arranged at the 21 Like the interface recess 41a9, the interface protrusion 41a is provided in the approximate center of the area surrounded by the DTI 22. 21 The height of the interface protrusion 41a may be the same as that of the interface recess 41a9. 21 The width of the recess 41a may also be the same as that of the interface recess 41a9.

[0334] <Modification 13 of the Third Embodiment> FIG. 56(a) shows a solid-state imaging device 1 according to a thirteenth modification of the third embodiment. 22 FIG. 56(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 22 Photoelectric conversion layer 40 22 The wiring layer side interface 41 22 FIG. 13 is a perspective view showing a solid-state imaging device 1 according to a thirteenth modification of the third embodiment. 22 The plurality of interface protrusions 41a 22 The plurality of interface protrusions 41a 22 is a light direction change unit 30 22 The interface protrusion 41a 22 The shape of the single unit is the same as that of the interface convex portion 41a of the modification 12 of the third embodiment. 21 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 22 A plurality of interface protrusions 41a are provided along the X-axis direction. 22 are provided along the Y-axis direction perpendicular to the X-axis. 22are arranged in a grid pattern. 22 The intervals between the interface protrusions 41a may be the same. 22 The interface protrusions 41a may be arranged regularly. 22 The intervals between the interface protrusions 41a may be different from each other. 22 may be irregularly arranged.

[0335] <Modification 14 of the Third Embodiment> FIG. 57(a) shows a solid-state imaging device 1 according to a modification 14 of the third embodiment. 23 FIG. 57(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 23 Photoelectric conversion layer 40 23 The wiring layer side interface 41 23 FIG. 14 is a perspective view showing a solid-state imaging device 1 according to a fourteenth modification of the third embodiment. 23 is one interface protrusion 41a 23 One interface protrusion 41a 23 is a light direction change unit 30 23 The interface protrusion 41a of the fourteenth modification of the third embodiment is configured as follows. 23 In other words, the interface protrusion 41a is rectangular in plan view. 23 The interface protrusions 41a are striped. 23 may extend from one DTI 22 to the other DTI 22.

[0336] <Modification 15 of the Third Embodiment> FIG. 58(a) shows a solid-state imaging device 1 according to a fifteenth modification of the third embodiment. 24 FIG. 58(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 24 Photoelectric conversion layer 40 24 The wiring layer side interface 41 24 FIG. 15 is a perspective view showing a solid-state imaging device 1 according to a fifteenth modification of the third embodiment. 24 The plurality of interface protrusions 41a 24 The plurality of interface protrusions 41a 24 is a light direction change unit 30 24 The interface protrusion 41a 24 The shape of the single unit is the same as that of the interface convex portion 41a of the modified example 14 of the third embodiment.23 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 24 The interface protrusion 41a 24 are spaced apart from each other along a second direction perpendicular to the first direction in which they extend.

[0337] <Modification 16 of the Third Embodiment> FIG. 59(a) shows a solid-state imaging device 1 according to a 16th modification of the third embodiment. 25 FIG. 59(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 25 Photoelectric conversion layer 40 25 The wiring layer side interface 41 25 12 is a perspective view showing an interface protrusion 41a of a twelfth modification of the third embodiment. 21 The shape of the interface protrusions is not limited to a rectangular parallelepiped. For example, the interface protrusions 41a of the modified example 16 of the third embodiment 25 The shape of the interface protrusion 41a is a quadrangular pyramid. 25 When the shape of the interface protrusion 41a is a quadrangular pyramid, 25 The cross-sectional shape of the solid-state imaging device 1 according to the sixteenth modification of the third embodiment is a triangle. 25 is one interface protrusion 41a 25 One interface protrusion 41a 25 is a light direction change unit 30 25 The interface protrusion 41a 25 is provided approximately in the center of the area surrounded by the DTI 22.

[0338] <Modification 17 of the Third Embodiment> FIG. 60(a) shows a solid-state imaging device 1 according to a seventeenth modification of the third embodiment. 26 FIG. 60(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 26 Photoelectric conversion layer 40 26 The wiring layer side interface 41 26 FIG. 17 is a perspective view showing a solid-state imaging device 1 according to a seventeenth modification of the third embodiment. 26 The plurality of interface protrusions 41a 26 The plurality of interface protrusions 41a 26 is a light direction change unit 30 26 The interface protrusion 41a 26The shape of the single unit is the same as that of the interface convex portion 41a of the modified example 16 of the third embodiment. 25 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 26 A plurality of interface protrusions 41a are provided along the X-axis direction. 26 are provided along the Y-axis direction perpendicular to the X-axis. 26 are arranged in a grid pattern. 26 The intervals between the interface protrusions 41a may be the same. 26 The interface protrusions 41a may be arranged regularly. 26 The intervals between the interface protrusions 41a may be different from each other. 26 may be irregularly arranged.

[0339] <Modification 18 of the Third Embodiment> FIG. 61(a) shows a solid-state imaging device 1 according to Modification 18 of the third embodiment. 27 FIG. 61(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 27 Photoelectric conversion layer 40 27 The wiring layer side interface 41 27 1 is a perspective view showing the solid-state imaging device 1. 27 is one interface protrusion 41a 27 One interface protrusion 41a 27 is a light direction change unit 30 27 Solid-state imaging device 1 27 The interface protrusion 41a 27 The cross section of the interface protrusion 41a is an ellipse. 27 The interface protrusions 41a are stripes extending in a predetermined direction. 27 The DTI 22 may also extend from one DTI 22 to the other DTI 22.

[0340] <Modification 19 of the Third Embodiment> FIG. 62(a) shows a solid-state imaging device 1 according to a 19th modification of the third embodiment. 28 FIG. 62(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 28 Photoelectric conversion layer 40 28 The wiring layer side interface 4128 The interface protrusion 41a is a perspective view showing the interface protrusion 41a. 28 The wiring layer side interface 41 28 A plurality of interface protrusions 41a may be provided. 28 is a light direction change unit 30 28 The interface protrusion 41a 28 The shape of the single unit is the same as that of the interface convex portion 41a of the modification 18 of the third embodiment. 27 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 28 The interface protrusion 41a 28 are spaced apart from each other along another direction perpendicular to the direction in which the

[0341] <Modification 20 of the Third Embodiment> FIG. 63(a) shows a solid-state imaging device 1 according to a 20th modification of the third embodiment. 29 FIG. 63(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 29 Photoelectric conversion layer 40 29 The wiring layer side interface 41 29 The shape of the interface recess is not limited to a rectangular parallelepiped. For example, the interface protrusion 41a of the modification 20 of the third embodiment 29 The shape of the interface protrusion 41a includes a curved surface. 29 When the shape of the interface includes a curved surface, for example, the interface protrusion 41a 29 The cross-sectional shape of the solid-state imaging device 1 according to the 20th modification of the third embodiment is a part of an ellipse. 29 is one interface protrusion 41a 29 One interface protrusion 41a 29 is a light direction change unit 30 29 The interface protrusion 41a 29 The interface protrusion 41a is provided at approximately the center of the area surrounded by the DTI 22. 29 The height of the interface protrusion 41a 21 The depth of the interface protrusion 41a may be the same as that of the interface protrusion 41a. 29 The diameter of the interface protrusion 41a 21 may be the same as the width of

[0342] <Modification 21 of the Third Embodiment> FIG. 64(a) shows a solid-state imaging device 1 according to a modification 21 of the third embodiment. 30 FIG. 64(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 30 Photoelectric conversion layer 40 30 The wiring layer side interface 41 30 FIG. 21 is a perspective view showing a solid-state imaging device 1 according to a modification 21 of the third embodiment. 30 The plurality of interface protrusions 41a 30 The plurality of interface protrusions 41a 30 is a light direction change unit 30 30 The interface protrusion 41a 30 The shape of the single unit is the same as that of the interface convex portion 41a of the modification 20 of the third embodiment. 29 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 30 A plurality of interface protrusions 41a are provided along the X-axis direction. 30 are provided along the Y-axis direction perpendicular to the X-axis. 30 are arranged in a grid pattern. 30 The intervals between the interface protrusions 41a may be the same. 30 The interface protrusions 41a may be arranged regularly. 30 The intervals between the interface protrusions 41a may be different from each other. 30 may be irregularly arranged.

[0343] <Modification 22 of the Third Embodiment> FIG. 65(a) shows a solid-state imaging device 1 according to a modification 22 of the third embodiment. 31 FIG. 65(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 31 Photoelectric conversion layer 40 31 The wiring layer side interface 41 31 FIG. 10 is a perspective view showing a solid-state imaging device 1 according to a modification 22 of the third embodiment. 31 is one interface protrusion 41a 31 One interface protrusion 41a 31 is a light direction change unit 30 31 The interface protrusion 41a of the modified example 22 of the third embodiment is configured as follows. 31In other words, the interface protrusion 41a is rectangular in plan view. 31 The interface protrusions 41a are striped. 31 may extend from one DTI 22 to the other DTI 22.

[0344] <Modification 23 of the Third Embodiment> FIG. 66(a) shows a solid-state imaging device 1 according to a modification 23 of the third embodiment. 32 FIG. 66(b) is a cross-sectional view showing the structure of the solid-state imaging device 1. 32 Photoelectric conversion layer 40 32 The wiring layer side interface 41 32 FIG. 10 is a perspective view showing a solid-state imaging device 1 according to a modification 23 of the third embodiment. 32 The plurality of interface protrusions 41a 32 The plurality of interface protrusions 41a 32 is a light direction change unit 30 32 The interface protrusion 41a 32 The shape of the single unit is the same as that of the interface convex portion 41a of the modified example 22 of the third embodiment. 31 The plurality of interface protrusions 41a may be the same as the plurality of interface protrusions 41a. 32 The interface protrusion 41a 32 are spaced apart from each other along a second direction perpendicular to the first direction in which they extend.

[0345] <Further variations> The solid-state imaging device 11 of the second embodiment and the solid-state imaging devices 12 to 18 of the modifications of the second embodiment are provided with a light scattering section 27 that generates diffracted light due to plasmons. Similarly, the solid-state imaging device 19 of the third embodiment and the solid-state imaging devices 1 of the modifications 1 to 23 are provided with a light scattering section 27 that generates diffracted light due to plasmons. 10 ~1 32 The light scattering section 27 also had a light scattering section 27 that generates diffracted light due to plasmons. Light scattering section 27 may be replaced with another element. The light scattering section may have a pyramidal structure with fine irregularities formed on the light incident surface.

[0346] 67(a) is a modified example of the solid-state imaging device 11 of the second embodiment and the modified solid-state imaging device 12. The solid-state imaging device 1A1 has a pyramidal structure 70 as a light scattering portion.

[0347] A solid-state imaging device 1A3 shown in Fig. 67(b) is a further modification of the solid-state imaging devices 13 and 14 that are modifications of the second embodiment. The solid-state imaging device 1A3 has a pyramidal structure 70 as a light scattering portion.

[0348] A solid-state imaging device 1A5 shown in Fig. 67(c) is a further modification of the solid-state imaging devices 15 and 16 that are modifications of the second embodiment. The solid-state imaging device 1A5 has a pyramidal structure 70 as a light scattering portion.

[0349] A solid-state imaging device 1A7 shown in Fig. 67(d) is a further modification of the solid-state imaging devices 17 and 18 which are modifications of the second embodiment. The solid-state imaging device 1A7 has a pyramidal structure 70 as a light scattering portion.

[0350] The solid-state imaging device 1A9 shown in FIG. 68(a) is the same as the solid-state imaging device 19 of the third embodiment and the solid-state imaging device 1 of the modified example. 11 The solid-state imaging device 1A9 has a pyramidal structure 70 as a light scattering portion.

[0351] Solid-state imaging device 1A shown in FIG. 68(b) 10 The solid-state imaging device 1 according to the modification of the third embodiment 10 , 1 12 This is a further modification of the solid-state imaging device 1A. 10 has a pyramidal structure 70 as a light scattering portion.

[0352] Solid-state imaging device 1A shown in FIG. 68(c) 13 The solid-state imaging device 1 according to the modification of the third embodiment 13 , 1 15 This is a further modification of the solid-state imaging device 1A. 13 has a pyramidal structure 70 as a light scattering portion.

[0353] Solid-state imaging device 1A shown in FIG. 68(d) 14 The solid-state imaging device 1 according to the modification of the third embodiment 14 , 1 16 This is a further modification of the solid-state imaging device 1A.14 has a pyramidal structure 70 as a light scattering portion.

[0354] Solid-state imaging device 1A shown in FIG. 68(e) 17 The solid-state imaging device 1 according to the modification of the third embodiment 17 , 1 19 This is a further modification of the solid-state imaging device 1A. 17 has a pyramidal structure 70 as a light scattering portion.

[0355] Solid-state imaging device 1A shown in FIG. 68(f) 18 The solid-state imaging device 1 according to the modification of the third embodiment 18 , 1 20 This is a further modification of the solid-state imaging device 1A. 18 has a pyramidal structure 70 as a light scattering portion.

[0356] Solid-state imaging device 1A shown in FIG. 69(a) 21 The solid-state imaging device 1 according to the modification of the third embodiment 21 , 1 23 This is a further modification of the solid-state imaging device 1A. 21 has a pyramidal structure 70 as a light scattering portion.

[0357] Solid-state imaging device 1A shown in FIG. 69(b) 22 The solid-state imaging device 1 according to the modification of the third embodiment 22 , 1 24 This is a further modification of the solid-state imaging device 1A. 22 has a pyramidal structure 70 as a light scattering portion.

[0358] Solid-state imaging device 1A shown in FIG. 69(c) 25 The solid-state imaging device 1 according to the modification of the third embodiment 25 , 1 27 This is a further modification of the solid-state imaging device 1A. 25 has a pyramidal structure 70 as a light scattering portion.

[0359] Solid-state imaging device 1A shown in FIG. 69(d) 26 The solid-state imaging device 1 according to the modification of the third embodiment 26, 1 28 This is a further modification of the solid-state imaging device 1A. 26 has a pyramidal structure 70 as a light scattering portion.

[0360] Solid-state imaging device 1A shown in FIG. 69(e) 29 The solid-state imaging device 1 according to the modification of the third embodiment 29 , 1 31 This is a further modification of the solid-state imaging device 1A. 29 has a pyramidal structure 70 as a light scattering portion.

[0361] Solid-state imaging device 1A shown in FIG. 69(f) 30 The solid-state imaging device 1 according to the modification of the third embodiment 30 , 1 32 This is a further modification of the solid-state imaging device 1A. 30 has a pyramidal structure 70 as a light scattering portion.

[0362] FIG. 70(a) shows a solid-state imaging device 1 according to a further modification of the third embodiment. 33 Solid-state imaging device 1 33 In addition to the same configuration as the solid-state imaging device 19 of the third embodiment, the solid-state imaging device 19 further includes a wiring layer 50 13 The solid-state imaging device 1 has a reflective film 55 embedded therein. 33 is a light direction change unit 30 33 In addition to the scattering effect of the light, there is also a reflection effect due to the reflective film 55. The reflective film 55 can reduce transmitted light.

[0363] <Fourth embodiment> FIG. 70(b) is a cross-sectional view showing the structure of a solid-state imaging device according to the fourth embodiment. In the solid-state imaging device 11 according to the second embodiment, the light-direction changing section 301 is provided at the wiring layer side interface 411. Since it is only necessary that the angle of incidence on the light scattering section 27 is different from the diffraction angle, the configuration for changing the light direction only needs to be provided on the light path in the photoelectric conversion section. For example, as shown in FIG. 70(b), the light-direction changing section 30 34 The DTI side interface 43 34 The DTI side interface 43 may be provided on the 34The DTI side interface 43 may be an inclined surface as in the second embodiment. 35 As in the third embodiment, light scattering body 44 may be provided in the light scattering member 44 . [Explanation of symbols]

[0364] 1...solid-state imaging device, 2...pixel unit, 3...pixel control unit, 4...signal processing unit, 8...pixel, 22...DTI, 26...photoelectric conversion unit, 26a...light input surface, 27...light scattering unit, L1...incident light, L2...absorbed light, 301...light direction change unit, 411...wiring layer side interface (back surface of photoelectric conversion unit), 41a 10 ...interface recess (light direction changer), 41a 21 ...Interface convex portion (light direction changer).

Claims

1. A solid-state imaging device including a plurality of pixels, The pixel is a light scattering section that receives incident light and generates absorbed light including scattered light; a photoelectric conversion unit that receives the absorbed light from a light input surface and generates a signal voltage according to the received absorbed light, the light scattering portion includes a plurality of metal structures arranged with a predetermined periodic length, and generates, as the scattered light, diffracted light of propagating light caused by plasmons that are not in a localized enhanced field mode corresponding to the incident light, A periodic length of the plurality of metal structures is set as a variable P, The real part of the refractive index of the photoelectric conversion unit is defined as a variable n, The wavelength of the incident light is set as a variable λ, The order l is 1 or 2, The variable P, the variable n, the variable λ, and the order l satisfy Equation (1). [Equation 1] Solid-state imaging device.

2. The plurality of metal structures are a first periodic structure along a first direction; 2. The solid-state imaging device according to claim 1, further comprising a second periodic structure extending along a second direction intersecting the first direction.

3. A solid-state imaging device as described in claim 2, wherein the periodic length of the first periodic structure is different from the periodic length of the second periodic structure.

4. A solid-state imaging device described in any one of claims 1 to 3, further comprising a charge retention film arranged between the light scattering portion and the photoelectric conversion portion.

5. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of bismuth or a material containing bismuth as a main component.

6. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 45 nm or more; 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of silver or a material containing silver as a main component.

7. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 50 nm or more, 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of copper or a material containing copper as a main component.

8. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 60 nm or more, 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of gold or a material containing gold as a main component.

9. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 30 nm or more, 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of platinum or a material containing platinum as a main component.

10. A solid-state imaging device as described in Claim 5, wherein the width of the trench is 70 nm or more.

11. A first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; A periodic length of the plurality of metal structures is set as a variable P, The number of periods of the plurality of metal structures is set as a variable M, The width of each of the plurality of metal structures is a variable W metal , The variable j is 0 or a positive integer, The variable W PD , the variable P, and the variable W metal satisfy the formula (2). [Equation 2] The solid-state imaging device according to any one of claims 1 to 10.

12. A distance from the plurality of metal structures to the light reflecting portion of the first isolation wall portion is defined as a variable X L , When the distance from the plurality of metal structures to the light reflecting portion of the second isolation wall portion is a variable X R , The solid-state imaging device according to claim 11 , wherein the variable X L and the variable X R are equal to each other.

13. A first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; A periodic length of the plurality of metal structures is set as a variable P, The number of periods of the plurality of metal structures is set as a variable M, The variable j is 0 or a positive integer, The variable W PD , the variable P, and the variable M satisfy the formula (3). [Equation 3] The solid-state imaging device according to any one of claims 1 to 10.

14. The photoelectric conversion unit includes a photoelectric conversion main surface including the light input surface and a photoelectric conversion back surface opposite to the photoelectric conversion main surface, a light direction changing section that changes the traveling direction of the absorbed light is provided on the rear surface of the photoelectric conversion section; the light direction changing unit changes the traveling direction of the absorbed light so that an angle of the absorbed light with respect to a reference axis after the traveling direction has been changed is different from an angle of the absorbed light with respect to the reference axis before the traveling direction has been changed; the light direction changing unit is in direct contact with the rear surface of the photoelectric conversion surface, The solid-state imaging device according to any one of claims 1 to 13, wherein the light direction changing portion includes only one light direction changing body that protrudes from the back surface of the photoelectric conversion element, which is a flat surface, or that is recessed from the back surface of the photoelectric conversion element, which is a flat surface.

15. Further comprising a first isolation wall portion provided between the adjacent pixels, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 35 nm or more; 5. The solid-state imaging device according to claim 1, wherein the light reflecting portion is made of aluminum or a material containing aluminum as a main component.

16. A first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; A periodic length of the plurality of metal structures is set as a variable P, The number of periods of the plurality of metal structures is set as a variable M, The width of each of the plurality of metal structures is a variable W metal , The variable j is 0 or a positive integer, The variable W PD , the variable P, and the variable W metal satisfy the formula (4). [Equation 4] The solid-state imaging device according to any one of claims 1 to 10.

17. A first isolation wall portion provided between adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; A periodic length of the plurality of metal structures is set as a variable P, The number of periods of the plurality of metal structures is set as a variable M, The variable j is 0 or a positive integer, The variable W PD , the variable P, and the variable M satisfy the formula (5). [Equation 5] The solid-state imaging device according to any one of claims 1 to 10.

18. A plurality of pixels; a first isolation wall portion provided between the adjacent pixels; the pixel includes a photoelectric conversion unit that receives absorbed light from a light input surface and generates a signal voltage according to the received absorbed light, the first isolation wall portion includes a trench and a light reflecting portion embedded in the trench; The width of the trench is 35 nm; The solid-state imaging device, wherein the light reflecting portion is formed of aluminum or a material containing aluminum as a main component.

19. A light scattering section that receives incident light and generates absorbed light including scattered light; a plurality of pixels each including a photoelectric conversion unit that generates a signal voltage according to the absorbed light; a first isolation wall portion provided between the adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench; The width of the trench is 35 nm or more; the light reflecting portion is formed of aluminum or a material containing aluminum as a main component, the light scattering portion includes a plurality of metal structures arranged at a predetermined periodic length, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; A periodic length of the plurality of metal structures is set as a variable P, The number of periods of the plurality of metal structures is set as a variable M, The width of each of the plurality of metal structures is a variable W metal , The variable j is 0 or a positive integer, The variable W PD , the variable P, and the variable W metal satisfy the formula (6). [Equation 6] Solid-state imaging device.

20. A light scattering section that receives incident light and generates absorbed light including scattered light; a plurality of pixels each including a photoelectric conversion unit that generates a signal voltage according to the absorbed light; a first isolation wall portion provided between the adjacent pixels and including a trench and a light reflecting portion embedded in the trench; a second isolation wall portion adjacent to the first isolation wall portion with the photoelectric conversion portion interposed therebetween, the second isolation wall portion including a trench and a light reflecting portion embedded in the trench; The width of the trench is 35 nm or more; the light reflecting portion is formed of aluminum or a material containing aluminum as a main component, The distance from the light reflecting portion of the first partition wall portion to the light reflecting portion of the second partition wall portion is defined as a variable W PD ; The real part of the refractive index of the photoelectric conversion portion is defined as a variable n Si , The wave number of the incident light is defined as a variable k 0 , The angle of diffraction caused by the light scattering portion on the incident light is defined as a variable θ d , The variable m is a natural number, The variable W PD , the variable n Si , the variable k 0 , the variable θ d , and the variable m satisfy equation (7). [Equation 7] Solid-state imaging device.

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