Imaging device and electronic device

Abstract

A plurality of sub-pixels are included in one pixel. An imaging device includes a sub-pixel, a pixel, and a pixel array. The sub-pixel includes a photoelectric conversion element that receives light incident at a predetermined angle and outputs an analog signal based on an intensity of the received light. The pixel includes a plurality of sub-pixels, a lens that converges light incident from the outside on the sub-pixels, and a photoelectric conversion element isolation portion that does not propagate information about the intensity of light acquired in the photoelectric conversion element to an adjacent photoelectric conversion element, and further includes a light shielding wall for shielding light incident on the lens of another pixel. The pixel array includes a plurality of pixels.

Description

Technical Field

[0001] This invention relates to imaging devices and electronic devices. Background Technology

[0002] In recent years, electronic devices such as smartphones, tablets, and personal computers (PCs) have demanded ingenious designs that improve portability through thinness / miniaturization and bezel-less displays. Image sensors for imaging and biometric authentication functions such as fingerprints are almost indispensable in these devices. To achieve compatibility with thinner casings, implementations that allow imaging devices to be included below the display are needed, and further thinning of optical lenses is desired, with the ultimate goal of eliminating optical lenses altogether. Furthermore, security measures against impersonation are also important in biometric authentication applications.

[0003] At the same time, there is a need to replace dedicated imaging electronic devices such as digital SLR cameras, mirrorless cameras, or compact digital cameras with mobile terminals such as smartphones that include imaging elements, and there is a need for the added value unique to cameras.

[0004] List of cited references

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-033505 Summary of the Invention

[0007] The problem to be solved by the present invention

[0008] One aspect of the present invention provides various embodiments of an imaging apparatus comprising a plurality of sub-pixels in a single pixel.

[0009] Technical solution

[0010] According to one embodiment, the imaging apparatus includes at least sub-pixels, pixels, and a pixel array. A sub-pixel includes a photoelectric conversion element that receives light incident at a predetermined angle and outputs an analog signal based on the intensity of the received light. A pixel includes a plurality of sub-pixels, a lens that converges externally incident light onto the sub-pixels, and a photoelectric conversion element isolation portion that prevents information about the intensity of light acquired in the photoelectric conversion element from propagating to adjacent photoelectric conversion elements. It also includes a light-shielding wall that blocks light incident on the lens of another pixel. The pixel array includes a plurality of pixels.

[0011] A lens can direct light incident parallel to the lens's optical axis onto a sub-pixel located at the center of a pixel. By converging the light incident parallel to the optical axis onto the sub-pixel located at the center of the pixel, the intensity of the light received by each pixel can be precisely converted into a signal.

[0012] A lens can cause a portion of light incident parallel to the optical axis of the lens to be incident on at least the sub-pixel located at the center of the pixel. As described above, light is incident on the sub-pixel located at the center, and light incident parallel to the optical axis can be received by the surrounding sub-pixels.

[0013] A lens can converge light incident at a certain angle relative to the lens's optical axis onto a sub-pixel positioned at a predetermined location within a pixel. By converging light in this way, light can be focused onto each sub-pixel based on the angle relative to the optical axis of the incident light within a pixel, thereby improving angular resolution. In other words, the effects of light from multiple angles can be captured within a single pixel.

[0014] The lens can be a reflow lens, and may include a height difference between the lens and the reflow blocking portion between adjacent lenses. Lenses (on-chip lenses) can be manufactured using various manufacturing methods. For example, a reflow lens manufactured through a reflow process can be used. In this case, a blocking portion can be provided to suppress the degradation of lens performance caused by the reflow process.

[0015] The return flow blocking portion can be at least a part of the light-shielding wall and can include a self-aligning return flow lens. As mentioned above, the blocking portion can also function as part of the light-shielding wall.

[0016] The lens can be a Fresnel lens. A Fresnel lens can be used as an on-plate lens. By using a Fresnel lens, the thickness of the lens can be suppressed.

[0017] A lens can be a diffractive lens. A diffractive lens can be used as an on-chip lens. A diffractive lens can suppress the thickness of the lens similarly to a Fresnel lens, and various characteristics of the lens, such as the position of the focal point in the pixel, can be easily controlled in the manufacturing process.

[0018] The pixel may also include an inner lens located between the lens and the photoelectric conversion element. Not only the on-chip lens but also the inner lens can be configured to overlap with the on-chip lens. By incorporating an inner lens, lens characteristics can be imparted in a way that makes mounting only the on-chip lens difficult and complicates its shape. Furthermore, the inner lens can also be used for pupil correction, etc.

[0019] Lenses can be arranged such that the position of the lens's center is offset from the position of the corresponding pixel in the pixel array. In this way, on-chip lenses can also be formed at positions offset from the pixel's center. For example, pupil correction can be achieved by having different lens positions in the central and end portions of the pixel array.

[0020] A pixel may include a color filter that transmits a predetermined color to at least one sub-pixel. By setting a color filter in the sub-pixels of each pixel, the color resolution of the light received in a pixel can be improved. Furthermore, by setting different color filters for light incident at different angles relative to the optical axis, light with different wavelengths for the same subject area can be received between different pixels.

[0021] When light passing through a color filter of the same color as its neighboring sub-pixels is incident on a sub-pixel, the sub-pixel does not need to include a photoelectric conversion element isolation section between the sub-pixel and its neighboring sub-pixels. Sub-pixels including color filters of the same color can be combined in this way. By combining sub-pixels in this way, the light receiving sensitivity to the color filter can be improved.

[0022] A pixel may include a plasma filter as at least one of the color filters. For example, by using a plasma filter, sensitivity in a predetermined wavelength region of interest can be particularly improved.

[0023] A pixel can include at least two types of color filters between the lens and the photoelectric conversion element. For example, a filter can be provided for the pixel and a filter can be provided for each sub-pixel of the pixel. The characteristics of the filters vary due to stacking. By providing different filters for the pixel and sub-pixels, various types of signal processing can be performed according to the characteristics. Furthermore, different color filters can of course be provided between the sub-pixels.

[0024] Color filters may include plasma filters located on the photoelectric conversion element side of the light-shielding wall. In this way, color filters and plasma filters can be used in an overlapping manner.

[0025] Color filters may include organic film color filters located on the lens side of the light-shielding wall.

[0026] One component of a color filter combination can have a transmission spectrum that transmits near-infrared light and absorbs visible light. In this way, an IR filter can be configured. Therefore, a pixel can include one or more filters with various properties.

[0027] When viewing the light-shielding wall from the optical axis direction of a pixel based on the lens's setting position, the light-shielding wall can be constructed in multiple levels at different locations. Through multi-level construction, the light beam or luminous flux incident on the sub-pixel can be controlled in various modes.

[0028] A light-shielding film can also be provided, constructed to block light incident on adjacent pixels from between light-shielding walls that are constructed in multiple levels. In the case of a multi-level structure, when viewed from the optical axis, gaps may occur between the light-shielding walls depending on the degree of deviation between the lower and upper light-shielding walls. In this case, light may be incident on the sub-pixel from adjacent pixels. To block light from adjacent pixels, a light-shielding film can be provided.

[0029] A pixel may include at least one aperture between the lens and the photoelectric conversion element, and the aperture may be a light-shielding film disposed in a direction intersecting the optical axis of the lens. The pixel may include an aperture for suppressing stray light, but the aforementioned light-shielding film can serve as the aperture.

[0030] A storage area can be further provided to temporarily store the charge converted from light in the photoelectric conversion element. For example, by including the storage area and reading out the charge stored in the storage area at a predetermined time, shutter distortion can be suppressed.

[0031] An anti-reflective film with a moth-eye structure can be provided on the lens side of the photoelectric conversion element, a reflective film can be provided on the side of the photoelectric conversion element opposite to the anti-reflective film, and a metal film can be provided in the semiconductor substrate of the isolation part of the photoelectric conversion element. By processing the surface of the light receiving element into a moth-eye structure, it can be used as a film to prevent the reflection of incident light. In addition, the reflective film can be provided on the opposite side of the light receiving area to improve the efficiency of converting received light into charge.

[0032] The photoelectric conversion element isolation portion may include a groove starting from the side of the semiconductor substrate that is not the irradiated surface, may have a height difference within a portion of the groove and include a vertical transistor, and may have an irradiated structure. In the manufacturing process, the imaging element may be formed from either the front or rear surface of the substrate. When the photoelectric conversion element isolation portion is formed from the side that is not the irradiated surface, the vertical transistor connected to wiring is easily formed during the manufacturing process.

[0033] The isolation portion of the photoelectric conversion element may include an impurity layer formed by solid-phase diffusion. In addition to ion implantation as described above, a well region in the substrate can also be formed by solid-phase diffusion.

[0034] The number of saturated electrons typically depends on the area of ​​the photoelectric conversion region at the pixel potential formed by ion implantation. Meanwhile, solid-state diffusion increases the number of saturated electrons by increasing the capacitance at the sidewalls of the trenches drilled into the substrate. That is, solid-state diffusion has the advantage of providing capacitance in the depth direction as the pixel size decreases, and this advantage diminishes in large pixel sizes. At the same time, solid-state diffusion increases process quantity and manufacturing cost, thus cost-effectiveness needs to be considered. Given this background, in a pixel, the aspect ratio of the semiconductor substrate thickness to the length of one side of the photoelectric conversion element can be at least 4 or higher.

[0035] A pixel can have at least two different sizes of subpixels. For example, by using subpixels of different sizes, it is possible to acquire both the attention sensitivity and attention desaturation signals in the same pixel at the same time.

[0036] According to an embodiment, a method for manufacturing an imaging element having sub-pixels and pixels including multiple sub-pixels includes the following steps: forming a well region in a substrate; forming a photoelectric conversion element isolation portion in the well region for isolating the light receiving region of the sub-pixels; forming an insulating film on the substrate; forming an interlayer film containing a light-transmitting material on the insulating film; forming a light-shielding wall on the photoelectric conversion element isolation portion that isolates the pixels in the interlayer film; and forming a lens on the interlayer film.

[0037] According to an embodiment, the electronic device includes an imaging device as described in any of the foregoing descriptions.

[0038] A signal processing apparatus can be provided to synthesize the output of multiple sub-pixels acquired by an imaging device and obtain three-dimensional stereoscopic information of a subject. According to this signal processing apparatus, various signal processing related to three-dimensional stereoscopic information can be performed based on the signals received from the sub-pixels.

[0039] A signal processing apparatus can be provided to synthesize the output of multiple sub-pixels acquired by an imaging device and expand the viewing angle. According to this signal processing apparatus, various signal processing related to the expansion of the viewing angle can be performed based on the signals received from the sub-pixels.

[0040] A signal processing apparatus can be provided to synthesize the output of multiple sub-pixels acquired by an imaging device and to calculate the number of pixels. Based on this signal processing apparatus, for example, high resolution of the image can be achieved.

[0041] A signal processing apparatus can be provided to synthesize the output of multiple sub-pixels acquired by an imaging device and refocus an image of the subject. According to this signal processing apparatus, for example, an image focused on multiple surfaces can be obtained from the acquired information.

[0042] A signal processing device can provide distance information of a subject based on the offset of a feature pattern in a multi-subpixel image acquired by an imaging device. According to this signal processing device, the distance to the subject can also be measured, for example.

[0043] A signal processing device can be provided, which includes an imaging apparatus and is configured to recognize human motion and convert that motion into operational commands. According to this signal processing device, gesture input can be performed.

[0044] A signal processing apparatus can be provided, configured to perform a Fourier transform on the output from a sub-pixel and perform deconvolution using the sub-pixel's point spread function. Based on this signal processing apparatus, deconvolution filters associated with various PSFs can be implemented.

[0045] A signal processing apparatus can be provided that divides an image into multiple regions, defines a point spread function for each region, and constructs a method for performing deconvolution on each region. According to this signal processing apparatus, deconvolution can be performed even for a PSF that varies for each region, i.e., an offset-varying PSF.

[0046] A display unit can be provided, and an imaging device can be provided on the side of the display unit opposite to the display surface. According to this imaging device, it can, for example, function as a personal authentication device, a built-in camera, etc., when the display screen is being used.

[0047] The system can provide address storage units for subpixels whose light from the subject is blocked by elements of the display unit, and signal processing devices configured to synthesize subpixel images that do not include subpixel signals. By including the signal processing devices, the accuracy of signal acquisition related to imaging from the display surface can be improved while displaying the display screen.

[0048] A storage unit can be provided that extracts features from a personal fingerprint image acquired by an imaging device and stores those features in a database, as well as a personal authentication device configured to acquire a fingerprint image of a subject during an authentication operation, extract features, compare them with the database, and make a determination. By providing a storage unit, the scope of personal authentication for terminal devices and the like can be expanded.

[0049] An imaging device can be provided that acquires fingerprint images through a flipping operation, and the fingerprint image acquisition method can be a flipping operation. For example, fingerprint information acquired from the imaging device can be quickly analyzed in an electronic device.

[0050] A storage unit can be provided that extracts features from personal vein images acquired by an imaging device and stores those features in a database, as well as a personal authentication device configured to acquire a subject's vein image during an authentication operation, extract and compare the features with the database, and make a judgment. Similar to the description above, the scope of vein authentication can be expanded.

[0051] The features of a vein image can be three-dimensional information. Based on the imaging device described above, information about its three-dimensional shape can also be obtained. By using this three-dimensional shape, personal authentication using more accurate vein information can be achieved.

[0052] This device can provide an anti-spoofing function by comparing the spectral information of a subject acquired by an imaging device with the rising spectrum of human skin around a wavelength of 590 nm to determine whether the subject is alive. The information captured by the imaging device can also prevent spoofing authentication.

[0053] It can provide an anti-spoofing function that detects vein pulsation from multiple image differences in vein images acquired by an imaging device and determines whether the vein image belongs to a living body, and similar to the description above, it can prevent spoofing authentication.

[0054] It can provide the function of calculating the signal ratio between the wavelength near 660 nm and the near-infrared region based on the spectral information of the subject acquired by the imaging device, and measuring the saturated oxygen concentration. For example, a pulse oximeter can be used.

[0055] Within a pixel, a wire grid polarizer can be provided in at least one of multiple sub-pixels.

[0056] Within a pixel, wire grid polarizers can be provided in multiple sub-pixels.

[0057] Linear grid polarizers can be provided for pixels.

[0058] Linear grating polarizers with multiple polarization directions can be provided.

[0059] At least two types of linear grid polarizers with polarization directions differing by 90 degrees can be provided.

[0060] It can provide wire grating polarizers with more than three polarization directions, and can perform normal analysis through fitting.

[0061] Subpixels can be combined with a wire grid polarizer and another filter in a hybrid manner.

[0062] Subpixels can receive light that passes through a linear grid polarizer and another filter.

[0063] Within a pixel, at least one sub-pixel may include a guided mode resonance (GMR) filter.

[0064] Within a pixel, GMR filters can be provided in multiple sub-pixels.

[0065] GMR filters can be provided for pixels.

[0066] Two or more GMR filters with different peak wavelengths can be provided.

[0067] Subpixels can be a combination of GMR filters and another type of filter. Attached Figure Description

[0068] Figure 1 This is a schematic view of an electronic device according to an embodiment.

[0069] Figure 2 This is a schematic cross-sectional view of an electronic device according to an embodiment.

[0070] Figure 3 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0071] Figure 4 This is a schematic plan view of the imaging pixels according to an embodiment.

[0072] Figure 5 This is a schematic diagram illustrating an imaging element according to an embodiment.

[0073] Figure 6 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0074] Figure 7 This is a schematic cross-sectional view of the element isolation section according to an embodiment.

[0075] Figure 8 This is a block diagram schematically illustrating signal processing-related elements according to an embodiment.

[0076] Figure 9 This is a flowchart illustrating the processing of an electronic device according to an embodiment.

[0077] Figure 10 This is a view schematically illustrating an imaging example according to an embodiment.

[0078] Figure 11 This is a view schematically illustrating an imaging example according to an embodiment.

[0079] Figure 12 This is a view schematically illustrating an imaging example according to an embodiment.

[0080] Figure 13 This is a view schematically illustrating an imaging example according to an embodiment.

[0081] Figure 14 This is a view schematically illustrating an imaging example according to an embodiment.

[0082] Figure 15 This is a view schematically illustrating an imaging example according to an embodiment.

[0083] Figure 16 This is a view schematically illustrating an imaging example according to an embodiment.

[0084] Figure 17 This is a view schematically illustrating an imaging example according to an embodiment.

[0085] Figure 18 This is a view that schematically illustrates an example of pixels according to an embodiment.

[0086] Figure 19 This is a view that schematically illustrates an example of pixels according to an embodiment.

[0087] Figure 20 This is a view that schematically illustrates an example of pixels according to an embodiment.

[0088] Figure 21 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0089] Figure 22 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0090] Figure 23 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0091] Figure 24 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0092] Figure 25 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0093] Figure 26 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0094] Figure 27 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0095] Figure 28A This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0096] Figure 28B This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0097] Figure 29 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0098] Figure 30 This is a plan view schematically illustrating an example of a filter arrangement according to an embodiment.

[0099] Figure 31 This is a schematic plan view illustrating an example of a filter according to an embodiment.

[0100] Figure 32 This is a diagram illustrating the characteristics of an example filter according to an embodiment.

[0101] Figure 33 This is a graph illustrating the characteristics of an example filter according to an embodiment.

[0102] Figure 34 This is a schematic cross-sectional view illustrating an example of a filter arrangement according to an embodiment.

[0103] Figure 35 This is a schematic cross-sectional view illustrating an example of a filter arrangement according to an embodiment.

[0104] Figure 36 This is a schematic cross-sectional view illustrating an example of a filter arrangement according to an embodiment.

[0105] Figure 37 This is a schematic cross-sectional view illustrating an example of a filter arrangement according to an embodiment.

[0106] Figure 38 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0107] Figure 39 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0108] Figure 40 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0109] Figure 41 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0110] Figure 42 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0111] Figure 43This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0112] Figure 44 This is a graph showing the sensitivity to the spectrum when using the filter according to the embodiment.

[0113] Figure 45 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0114] Figure 46 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0115] Figure 47 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0116] Figure 48 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0117] Figure 49 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0118] Figure 50 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0119] Figure 51 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0120] Figure 52 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0121] Figure 53 This is a plan view of an example of a back-etching lens.

[0122] Figure 54 This is a plan view of an example of a recirculation lens.

[0123] Figure 55 This is a perspective view of an AFM image showing an example of a recirculation lens.

[0124] Figure 56 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0125] Figure 57 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0126] Figure 58 This is a schematic plan view of the imaging pixels according to an embodiment.

[0127] Figure 59 This is a schematic plan view of the imaging pixels according to an embodiment.

[0128] Figure 60 This is a schematic plan view of the imaging pixels according to an embodiment.

[0129] Figure 61 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0130] Figure 62 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0131] Figure 63 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0132] Figure 64 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0133] Figure 65 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0134] Figure 66 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0135] Figure 67 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0136] Figure 68 This is a plan view illustrating the sub-pixel arrangement according to an embodiment.

[0137] Figure 69 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0138] Figure 70 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0139] Figure 71 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0140] Figure 72 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0141] Figure 73 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0142] Figure 74 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0143] Figure 75 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0144] Figure 76This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0145] Figure 77 This is a schematic plan view of a lens according to an embodiment.

[0146] Figure 78 This is a schematic cross-sectional view of a lens according to an embodiment.

[0147] Figure 79 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0148] Figure 80 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0149] Figure 81 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0150] Figure 82 This is a schematic cross-sectional view of a diffractive lens according to an embodiment.

[0151] Figure 83 This is a schematic cross-sectional view of a diffractive lens according to an embodiment.

[0152] Figure 84 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0153] Figure 85 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0154] Figure 86 This is a view illustrating an example of a pixel array and a diffractive lens included in the pixels according to an embodiment.

[0155] Figure 87 This is a view illustrating an example of a pixel array and a diffractive lens included in the pixels according to an embodiment.

[0156] Figure 88 This is a view illustrating an example of a pixel array and a diffractive lens included in the pixels according to an embodiment.

[0157] Figure 89 This is a view showing the state of imaging a finger according to an embodiment.

[0158] Figure 90 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0159] Figure 91 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0160] Figure 92This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0161] Figure 93 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0162] Figure 94 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0163] Figure 95 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0164] Figure 96 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0165] Figure 97 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0166] Figure 98 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0167] Figure 99 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0168] Figure 100 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0169] Figure 101 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0170] Figure 102 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0171] Figure 103 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0172] Figure 104 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0173] Figure 105 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0174] Figure 106 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0175] Figure 107 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0176] Figure 108 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0177] Figure 109 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0178] Figure 110 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0179] Figure 111 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0180] Figure 112 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0181] Figure 113 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0182] Figure 114 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0183] Figure 115 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0184] Figure 116 This is a graph showing the sensitivity of each sub-pixel according to an embodiment.

[0185] Figure 117 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0186] Figure 118 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0187] Figure 119 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0188] Figure 120 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0189] Figure 121 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0190] Figure 122 This is a schematic cross-sectional view of the isolation section according to an embodiment.

[0191] Figure 123 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0192] Figure 124 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0193] Figure 125 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0194] Figure 126 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0195] Figure 127 This is a schematic planar cross-sectional view of the imaging pixels according to an embodiment.

[0196] Figure 128 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0197] Figure 129 This is a schematic planar cross-sectional view of the imaging pixels according to an embodiment.

[0198] Figure 130 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0199] Figure 131 This is a schematic planar cross-sectional view of the imaging pixels according to an embodiment.

[0200] Figure 132 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0201] Figure 133 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0202] Figure 134 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0203] Figure 135 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0204] Figure 136 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0205] Figure 137A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0206] Figure 137B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0207] Figure 138A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0208] Figure 138B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0209] Figure 139A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0210] Figure 139BThis is a schematic view illustrating a semiconductor process according to an embodiment.

[0211] Figure 140 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0212] Figure 141 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0213] Figure 142 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0214] Figure 143 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0215] Figure 144 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0216] Figure 145 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0217] Figure 146 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0218] Figure 147 This is a schematic diagram illustrating a semiconductor process according to an embodiment.

[0219] Figure 148 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0220] Figure 149 This is a schematic diagram illustrating a semiconductor process according to an embodiment.

[0221] Figure 150 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0222] Figure 151 This is a schematic diagram illustrating a semiconductor process according to an embodiment.

[0223] Figure 152 These are graphs and charts showing the properties of the material with respect to ultraviolet light according to the embodiments.

[0224] Figure 153A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0225] Figure 153B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0226] Figure 153C This is a schematic view illustrating a semiconductor process according to an embodiment.

[0227] Figure 154A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0228] Figure 154B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0229] Figure 154C This is a schematic view illustrating a semiconductor process according to an embodiment.

[0230] Figure 155 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0231] Figure 156 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0232] Figure 157 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0233] Figure 158 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0234] Figure 159 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0235] Figure 160 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0236] Figure 161 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0237] Figure 162 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0238] Figure 163 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0239] Figure 164 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0240] Figure 165 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0241] Figure 166 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0242] Figure 167 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0243] Figure 168This is a schematic view illustrating a semiconductor process according to an embodiment.

[0244] Figure 169 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0245] Figure 170 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0246] Figure 171 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0247] Figure 172 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0248] Figure 173 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0249] Figure 174 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0250] Figure 175 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0251] Figure 176 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0252] Figure 177 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0253] Figure 178 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0254] Figure 179 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0255] Figure 180 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0256] Figure 181 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0257] Figure 182 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0258] Figure 183 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0259] Figure 184 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0260] Figure 185 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0261] Figure 186 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0262] Figure 187 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0263] Figure 188 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0264] Figure 189 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0265] Figure 190 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0266] Figure 191 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0267] Figure 192 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0268] Figure 193 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0269] Figure 194 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0270] Figure 195 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0271] Figure 196 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0272] Figure 197 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0273] Figure 198 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0274] Figure 199 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0275] Figure 200 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0276] Figure 201This is a schematic view illustrating a semiconductor process according to an embodiment.

[0277] Figure 202 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0278] Figure 203 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0279] Figure 204 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0280] Figure 205 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0281] Figure 206 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0282] Figure 207 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0283] Figure 208 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0284] Figure 209 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0285] Figure 210 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0286] Figure 211 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0287] Figure 212 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0288] Figure 213 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0289] Figure 214 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0290] Figure 215 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0291] Figure 216 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0292] Figure 217 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0293] Figure 218 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0294] Figure 219 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0295] Figure 220 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0296] Figure 221 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0297] Figure 222 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0298] Figure 223 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0299] Figure 224 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0300] Figure 225 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0301] Figure 226 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0302] Figure 227 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0303] Figure 228 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0304] Figure 229 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0305] Figure 230 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0306] Figure 231 is a view schematically illustrating a semiconductor process according to an embodiment.

[0307] Figure 232 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0308] Figure 233 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0309] Figure 234 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0310] Figure 235 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0311] Figure 236 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0312] Figure 237 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0313] Figure 238 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0314] Figure 239 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0315] Figure 240 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0316] Figure 241 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0317] Figure 242 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0318] Figure 243 This is a schematic view illustrating a semiconductor process according to an embodiment.

[0319] Figure 244A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0320] Figure 244B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0321] Figure 245A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0322] Figure 245B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0323] Figure 246A This is a schematic view illustrating a semiconductor process according to an embodiment.

[0324] Figure 246B This is a schematic view illustrating a semiconductor process according to an embodiment.

[0325] Figure 247 This is a block diagram schematically illustrating a signal processing apparatus according to an embodiment.

[0326] Figure 248This is a block diagram schematically illustrating a signal processing apparatus according to an embodiment.

[0327] Figure 249 This is a flowchart illustrating the processing of an electronic device according to an embodiment.

[0328] Figure 250 This is a view showing examples of subpixels in a pixel according to an embodiment.

[0329] Figure 251 This is a graph showing the angle dependence of the sensitivity of sub-pixels according to an embodiment.

[0330] Figure 252A This is a graph showing an example of pixel values ​​for a sub-pixel image according to an embodiment.

[0331] Figure 252B This is a graph showing an example of pixel values ​​for a sub-pixel image according to an embodiment.

[0332] Figure 253 This is a graph illustrating an example of pixel values ​​in a composite sub-pixel image according to an embodiment.

[0333] Figure 254 This is a diagram illustrating a sub-pixel image according to an embodiment.

[0334] Figure 255 This is a schematic cross-sectional view of the imaging pixels according to an embodiment.

[0335] Figure 256 This is an illustration showing a sub-pixel image according to an embodiment.

[0336] Figure 257 This is a view showing an example of a composite image according to an embodiment.

[0337] Figure 258 This is a block diagram schematically illustrating a signal processing apparatus according to an embodiment.

[0338] Figure 259 This is a flowchart illustrating the processing of an electronic device according to an embodiment.

[0339] Figure 260 This is a diagram illustrating a sub-pixel image according to an embodiment.

[0340] Figure 261 This is a schematic diagram illustrating the positional relationship between the subject and pixels according to an embodiment.

[0341] Figure 262 This is a diagram illustrating a sub-pixel image according to an embodiment.

[0342] Figure 263 This is a diagram illustrating a sub-pixel image according to an embodiment.

[0343] Figure 264 This is a diagram illustrating a sub-pixel image according to an embodiment.

[0344] Figure 265 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0345] Figure 266 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0346] Figure 267 This is a schematic cross-sectional view of an electronic device according to an embodiment.

[0347] Figure 268 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0348] Figure 269 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0349] Figure 270 This is a schematic view illustrating the light reception of an electronic device according to an embodiment.

[0350] Figure 271 It is a graph showing the light transmission and reflection characteristics of human skin.

[0351] Figure 272 This is a schematic view illustrating an example of a filter according to an embodiment.

[0352] Figure 273 This is a schematic view illustrating an example of a filter according to an embodiment.

[0353] Figure 274 This is a schematic view illustrating an example of a filter according to an embodiment.

[0354] Figure 275 This is a schematic view illustrating an example of a filter according to an embodiment.

[0355] Figure 276 This is a schematic view illustrating an example of a filter according to an embodiment.

[0356] Figure 277 This is a schematic view illustrating an example of a filter according to an embodiment.

[0357] Figure 278 This is a schematic view illustrating an example of a filter according to an embodiment.

[0358] Figure 279 This is a schematic view illustrating an example of a filter according to an embodiment.

[0359] Figure 280This is a schematic view illustrating an example of a filter according to an embodiment.

[0360] Figure 281 This is a schematic view illustrating an example of a filter according to an embodiment.

[0361] Figure 282 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0362] Figure 283 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0363] Figure 284 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0364] Figure 285 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0365] Figure 286 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0366] Figure 287 This is a view schematically illustrating an example of a filter arrangement according to an embodiment.

[0367] Figure 288 This is a view showing an example of a filter according to an embodiment.

[0368] Figure 289 This is a view showing an example of a filter according to an embodiment.

[0369] Figure 290 This is a view showing an example of a filter according to an embodiment.

[0370] Figure 291 This is a view showing an example of a filter according to an embodiment.

[0371] Figure 292 This is a view illustrating an example of the wavelength characteristics of a filter according to an embodiment. Detailed Implementation

[0372] In the following description, embodiments of the imaging apparatus and electronic device will be illustrated with reference to the accompanying drawings. The main structural components of the imaging apparatus and electronic device will be described primarily below, but the imaging apparatus and electronic device may have structural components and functions not shown or described.

[0373] The following description does not exclude components or functions that are not shown or described. Additionally, dimensions, shapes, aspect ratios, etc., may sometimes be changed for illustrative purposes, but will have appropriate dimensions, shapes, aspect ratios, etc., during installation. Furthermore, the accompanying drawings may show sectional views intended to include end views. That is, it should be noted that what is described as a sectional view includes views showing only the cut planes.

[0374] Note that in the following description, the signal to be acquired is referred to as image information or imaging information. Image information and imaging information are broad concepts and include still images, moving images, or a frame of an image from a video.

[0375] In this invention, regarding direction, such as Figure 1 As shown in the schematic diagram of electronic device 1, the first direction is the rightward direction in the diagram, the second direction is the direction perpendicular to the diagram, and the third direction is the upward direction in the diagram. That is, the second direction is the direction that intersects with the first direction, and the third direction is the direction that intersects with both the first and second directions. The term "intersect" can include an intersection at a 90-degree angle, or it may not be strictly 90 degrees. Furthermore, as can be seen from the diagram, the first and second directions are distinguished for convenience, and they are equivalent even if they are interchanged.

[0376] Furthermore, the imaging elements described later are also defined according to the electronic device, and the imaging elements are arranged in an array along the first direction and the second direction (i.e., the direction intersecting the first direction). That is, the semiconductor substrate is disposed along the first direction and the second direction. Then, the third direction is the direction intersecting the first direction and the second direction, and is a direction substantially perpendicular to the semiconductor substrate.

[0377] In this specification, the electronic device will be described in the following order.

[0378] 1. First Embodiment

[0379] This section will illustrate a non-limiting example of the overall construction of an electronic device.

[0380] 2. Examples 2 to 6

[0381] This illustrates some non-limiting examples where the positions of the imaging elements and the light source are not restricted.

[0382] 3. Examples 7 to 9

[0383] This illustrates some non-restrictive examples where the pixel shape is not restricted.

[0384] 4. Examples 10 to 17

[0385] Some non-limiting examples of planar arrangements of filters for pixels are illustrated.

[0386] 5. Examples 18 to 21

[0387] Some non-limiting examples of planar arrangements of filters for sub-pixels are illustrated.

[0388] 6. Examples 22 to 29

[0389] Some non-limiting examples of the arrangement of filters for pixels and subpixels on a substrate are illustrated.

[0390] 7. Examples 30 to 41

[0391] Some non-limiting examples of lenses included in imaging elements are illustrated.

[0392] 8. Examples 42 to 66

[0393] Some non-limiting examples of peripheral techniques for photoelectric conversion elements in pixels are illustrated.

[0394] 9. Examples 67 to 92

[0395] The above embodiments illustrate some imaging elements and provide non-limiting examples of semiconductor processes.

[0396] (9-1) Examples 67 to 75: The process for manufacturing photoelectric conversion elements in pixels is described.

[0397] (9-2) Examples 76 to 92: The process for manufacturing a light-shielding wall for isolating pixels, a lens constituting a pixel, a filter, etc. is described.

[0398] 10. Examples 93 to 104: Other operations and structures of signal processing, electronic devices, etc. are described.

[0399] Some non-limiting examples of signal processing for imaging elements having the construction of each of the above embodiments are illustrated.

[0400] 11. Examples 105 and 106

[0401] Different, non-limiting examples of filters used for subpixels are illustrated.

[0402] As described above, in this invention, firstly, the construction of the entire device including the sensor will be explained by example. Thereafter, a light-receiving sensor will be described by specific example for each construction element. Next, the manufacturing process of the light-receiving sensor will be described by specific example. Finally, constructions other than signal processing and semiconductors will be described by specific example.

[0403] (First Embodiment)

[0404] [Electronic Devices]

[0405] First, the structure and function of the light-receiving element in the general-purpose electronic device 1 will be described. More details will be explained in each embodiment described below.

[0406] Figure 1 An external view and a cross-sectional view of an electronic device including an imaging apparatus according to the present invention are schematically shown. The cross-sectional view shows a section AA along alternating long and short lines shown in the external view, including the display portion of the display unit 2. For ease of explanation, the casing portion of the electronic device 1 and circuitry other than the display portion are omitted.

[0407] In the external view, the display screen 1a extends to near the outer diameter of the electronic device 1, and the width of the bezel 1b surrounding the display screen 1a is set to less than a few millimeters. Typically, the front-facing camera is mounted on the bezel 1b. In this embodiment, for example, as the imaging device 3, as shown by the dashed line in the external view, the front-facing camera can be positioned approximately at the center of the lower part of the display screen 1a in the second direction. In this way, by arranging the front-facing camera, which is the imaging element 3, on the opposite side of the display surface of the display unit 2, it is not necessary to arrange the front-facing camera in the bezel 1b, and the width of the bezel 1b can be narrowed.

[0408] Notice, Figure 1 The external view is shown as an example, and the imaging device 3 (i.e., the front camera) can be arranged on the side of the display unit 2 opposite to the display surface (rear surface side) and located at any position on the display screen 1a in the first and second directions. For example, the front camera can be arranged on the peripheral edge portion (end portion or boundary portion) of the display screen 1a. Although one imaging device 3 is shown, the imaging device 3 is not limited to this, and more imaging optical systems can be arranged on the side opposite to the display surface. That is, multiple imaging elements 10 can be arranged in one electronic device 1.

[0409] For example, as shown in the cross-sectional view, the imaging element 3 is disposed on the rear surface side of the display unit 2, opposite to the display surface side that serves as the display surface. Note that this cross-sectional view is shown in an abbreviated manner. For example, similarly to the above, in Figure 1 The sectional view also includes an adhesive layer, but this is omitted for simplicity.

[0410] For example, such as Figure 1 As shown, the imaging element in this invention is disposed below the display of the electronic device 1.

[0411] Figure 2 This is a schematic cross-sectional view of electronic device 1. That is, Figure 2 Showing more details Figure 1The imaging device 3 is shown in a cross-sectional view, and its relationship with other components is also shown. The electronic device 1 can be an electronic device such as a smartphone, mobile phone, tablet computer, or PC that combines display and imaging functions. The electronic device 1 equipped with an imaging element is not limited to these forms and can be used in various devices, etc.

[0412] The electronic device 1 includes an imaging device 3 (camera module, etc.) arranged on the side opposite to the display surface of the display unit 2, and the imaging device 3 performs imaging through the display unit 2.

[0413] like Figure 2 As shown, the display unit 2 is a structure in which the display panel 4, the circular polarizing plate 5, the touch panel 6 and the protective glass 7 are stacked sequentially along a third direction. Figure 2 The stacked structure is shown as an example, and adhesive or bonding layers can be provided between the display panel 4, the circular polarizer 5, the touch panel 6, and the protective glass 7 as needed. Furthermore, the order of the circular polarizer 5 and the touch panel 6 can be appropriately changed according to the design.

[0414] The imaging device 3 is disposed on the side of the display unit 2 opposite to the display surface. The imaging device 3 includes, for example, an imaging element 10 and an optical system 9.

[0415] Multiple imaging devices 3 can be provided for a single display unit 2 of the electronic device 1. Light emitted on the display surface passes through an optical system 9, which serves as an opening, and propagates to the imaging element 10. Alternatively, an optical system with certain optical characteristics can be provided instead of an opening, such as optical characteristics that adjust the optical path length and change the polarization state.

[0416] The optical system 9 propagates light emitted onto the display surface to the imaging element. For example, the optical system 9 may be a simple opening disposed in the display panel 4. As another example, the optical system 9 may include a light propagation path made of a highly transmissive material, may have a waveguide structure surrounded by a low-refractive-index material, or may have a lens shape. In the case of a lens shape, the optical system 9 may be a concept including an on-chip lens formed on the light-receiving element. Furthermore, the imaging device 3 may not include the optical system 9.

[0417] Note that the imaging device 3 itself may be included in the imaging element 10. That is, the imaging element 10 may be suitably formed on the underside of the display panel 4 of the display.

[0418] Furthermore, in the following description, the imaging device 3 has a structure including the aforementioned optical system 9 and imaging element 10, but it may also have a concept that further includes an A / D conversion unit, an information processing unit, etc. That is, in the case of describing the imaging device 3 in this invention, as... Figure 1As shown, the imaging device 3 may have a concept that includes not only the structure of the imaging system, but also an information processing unit for outputting information containing image data and recognition results.

[0419] Although not shown in detail, for example, display panel 4 may include an organic light-emitting device (OLED), a liquid crystal such as a TFT, a microLED, or a microOLED as an optical system for display (display optical system). The display optical system may include light-emitting elements based on another display principle.

[0420] For example, the light-emitting element in a display optical system can have a stripe array or a mosaic array. The light-emitting elements can be arranged in an array in a first direction and a second direction, or they can have tilted or partially thinned pixels. For example, the array can be arranged in the same order as described below regarding the array of light-receiving elements. Furthermore, in a display optical system, the light-emitting element can include stacked filters to change the displayed color. When OLEDs or similar materials are used as light-emitting elements, the display panel 4 can include multiple layers, such as an anode layer and a cathode layer. Furthermore, these layers can include a high-transmittance material.

[0421] The display panel 4 may be provided with low-transmittance components such as a color filter layer. If the display panel 4 includes an OLED, for example, it may include a substrate 4a and an OLED unit. The substrate 4a may include, for example, polyimide. If the substrate 4a includes a low-transmittance material such as polyimide, an opening may be formed depending on the arrangement of the imaging device 3. Furthermore, the display panel 4 may include a light propagation path containing a high-transmittance material, and may have a waveguide structure with a low-refractive-index material surrounding a low-absorption, high-refractive-index material, or may have a lens shape. Similarly, in this case, light incident from the display surface of the display unit 2 is received by the imaging device 3 and converted into a signal.

[0422] The light-emitting element included in the display panel 4 can emit light when fingerprint information is acquired, such as in fingerprint authentication. That is, the light-emitting element included in the display panel 4 can operate as an element that outputs an image on the display surface of the display unit 2, and can also operate as a light-emitting element when fingerprints are acquired.

[0423] For example, the circular polarizer 5 is used to reduce glare on the display screen 1a or improve its visibility even in bright environments.

[0424] A touch sensor is incorporated into the touch panel 6. Various types of touch sensors exist, such as capacitive and resistive film sensors, but any type can be used. Furthermore, the touch panel 6 and the display panel 4 can be integrated together.

[0425] Through design, the circular polarizer 5 and the touch panel 6 can be interchanged in the third-order orientation.

[0426] The protective glass 7 is used to protect the display panel 4, etc. As mentioned above, an adhesive layer or bonding layer, such as an optically clear adhesive (OCA), can be provided in appropriate locations.

[0427] Figure 3 This is a view schematically illustrating an example of imaging performed by an imaging element according to an embodiment. For example, electronic device 1 may have the function of reading a person's fingerprint or performing personal authentication. This personal authentication may be performed based on feature points such as fingerprints, or it may be performed using, for example, a trained neural network model. As will be explained later, for example, an option for determining whether the subject is alive may be added.

[0428] The part where the fingers are placed is, for example, Figure 1 or Figure 2 The protective glass 7 is shown. As described above, for example, light is incident on the imaging element 10 via the protective glass 7, the touch panel 6, the circular polarizer 5, and the display panel 4.

[0429] Imaging element 10 receives light R1 reflected from reading surface 12 of electronic device 1, which is light L1 emitted from inside electronic device 1. Light receiving element in imaging element 10 receives the light and performs appropriate processing on it.

[0430] As another example, light R2 reflected around the reading surface 12 can be received, light R2 being light L2 emitted from outside the electronic device 1.

[0431] As another example, light R3 can be received via the reading surface 12. This light is emitted from inside the electronic device 1 but is not transmitted to the reading surface of the electronic device 1. Instead, it is transmitted to a person's finger or the like to the extent that it reaches the skin and is reflected and scattered.

[0432] As another example, light D4 can be received, which is external light L4 that is transmitted and scattered by a person's finger or the like and diffracted on the reading surface 12. Of course, the direction of the light is not limited to the direction of external light L4, and light, for example, from the direction of light L2, can pass through the finger, and light reflected and scattered inside the finger can be received.

[0433] As described below, the imaging element 10 includes pixels arranged in an array. The imaging element 10 acquires information such as fingerprints by reading the state of reflected and diffracted light incident on the pixels in the pixel array.

[0434] For example, the reading surface 12 is configured such that reflection is less likely to occur in areas where the fingerprint ridges and the reading surface 12 come into contact, and conversely, total internal reflection occurs in areas where the fingerprint ridges and the reading surface 12 do not come into contact. Because of this reading surface 12, fingerprint information is acquired by reading the areas where fingerprint ridges are present and the areas where fingerprint ridges are not present using each pixel.

[0435] The imaging device of electronic device 1 will be described in more detail next.

[0436] [Imaging element]

[0437] Figure 4 This is a schematic plan view illustrating the imaging pixels included in the imaging element of the imaging apparatus 3 according to an embodiment. For example, Figure 4 From Figure 2 The diagram shows a plan view of the imaging device 3 viewed from the direction of the reading surface 12. Hereinafter, for the sake of simplicity, the term "pixel" refers to an imaging pixel and is not distinguished from a light-emitting pixel unless otherwise stated.

[0438] Light via Figure 2 The optical system 9 shown is incident on Figure 4 The imaging element 10 in the imaging apparatus 3 shown is on a pixel. For example, as shown in the top view, the imaging element 10 includes a pixel array having pixels 102 arranged in an array along a first direction and a second direction. That is, the optical system 9 is arranged to appropriately focus the desired light onto the area present in the pixel 102.

[0439] As described above, the imaging element 10 includes a plurality of pixels 102 arranged in an array. Figure 4 The arrangement of pixels shown is for illustrative purposes only and is not limited to this arrangement. Another example will be described in detail below.

[0440] The lower view shows a plan view of pixel 102. The lower view is an enlarged view of pixel 102 in the upper view. Pixel 102 includes, for example, a lens 104 and a plurality of subpixels 106.

[0441] For example, a lens 104 is provided for a pixel 102. This embodiment is not limited to this, and the lens 104 may include a plurality of stacked lenses. As shown in the plan view, the lens 104 is arranged such that light is focused onto the sub-pixel 106 included in pixel 102. For example, the lens 104 is arranged such that light incident perpendicularly to the vertical direction relative to the drawing is focused onto the sub-pixel 106 located at the center of pixel 102.

[0442] As an example, light incident parallel to the optical axis of lens 104 is focused onto sub-pixel 106 located at the center of pixel 102. Lens 104 may be, for example, an on-chip microlens array formed on a chip used to form imaging element 10. As explained in the manufacturing process described later, lens 104 may be, for example, a lens formed by etch-back.

[0443] Figure 5 This is a plan view schematically illustrating an example of the construction of an imaging apparatus 3 according to an embodiment. The imaging apparatus 3 includes a pixel array 100, an imaging control unit 20, a line drive unit 22, and a column signal processing unit 24. Note that in this figure, for convenience, a first direction and a second direction are shown, and the arrangement of each component is not limited to these directions.

[0444] The pixel array 100 includes sub-pixels 106 arranged in an array on a semiconductor substrate and having photoelectric conversion elements. In addition, line drive lines 220 and column signal lines 240 are arranged in the pixel array 100.

[0445] As an example Figure 4 As shown, a plurality of sub-pixels 106 are disposed in pixel 102. Sub-pixels 106 include photoelectric conversion units and a plurality of pixel transistors, the photoelectric conversion units being, for example, photodiodes that generate and accumulate charge based on emitted light.

[0446] A pixel transistor includes a source / drain region (not shown) formed on the front surface of a semiconductor substrate and a gate electrode formed across a gate insulating film. A pixel transistor may include multiple MOS transistors, including a transfer transistor, a reset transistor, a select transistor, and an amplification transistor. Furthermore, a pixel transistor may include multiple transistors other than the select transistor described above.

[0447] Furthermore, a pixel-sharing structure comprising multiple sub-pixels 106, multiple transmission transistors, a shared floating diffuser, and another shared pixel transistor can be adopted. For example, sub-pixels 106 belonging to the same pixel 102 can share a floating diffuser and transistors that each constitute one of the aforementioned pixel transistors.

[0448] The imaging control unit 20 acquires signals from the imaging element 10 and performs control to transmit the acquired signals appropriately.

[0449] Line drive unit 22 is connected to imaging control unit 20 and multiple line drive lines 220. Line drive lines 220 are connected to at least one of the pixel transistors included in each sub-pixel 106 belonging to a line (i.e., a line along a first direction) in pixel array 100. Under the control of imaging control unit 20, line drive unit 22 selectively outputs drive signals for outputting signals from sub-pixels 106 to line drive lines 220 for each line.

[0450] The pixel circuit generates an image signal based on the charge generated by the photoelectric conversion element of the sub-pixel 106, and the image signal is controlled by the control signal of the line driving unit 22. In the array unit of the sub-pixel 106, the line driving lines 220 and column signal lines 240 are arranged in a matrix, for example, along a first direction and a second direction.

[0451] Line drive line 220 is a signal line that transmits control signals for the pixel circuitry in sub-pixels 106, and is arranged for each row of pixel array 100. Line drive line 220 is commonly connected to the sub-pixels 106 arranged in each row.

[0452] The column signal processing unit 24 is connected to the imaging control unit 20 and multiple column signal lines 240. The column signal lines 240 are connected to at least one of the pixel transistors included in each sub-pixel 106 belonging to a column (i.e., a column along the second direction) in the pixel array 100. Under the control of the imaging control unit 20, for each column, the column signal processing unit 24 acquires the image signal obtained by the photoelectric conversion of the sub-pixel 106 via the column signal lines 240. The acquired image signal is then output to the appropriate location.

[0453] The column signal lines 240 are signal lines that transmit image signals based on the charges generated in the sub-pixels 106, and are arranged for each column of the pixel array 100. The column signal lines 240 are connected together to the sub-pixels 106 arranged in each column.

[0454] The imaging control unit 20 appropriately outputs the light received by each sub-pixel 106 as an analog image signal by controlling the line drive unit 22 and the column signal processing unit 24.

[0455] Line drive unit 22 generates control signals for the pixel circuit. Line drive unit 22 transmits the generated control signals to the pixel circuit of the photoelectric conversion element via line drive line 220. Column signal processing unit 24 processes the image signal based on the charge generated in the sub-pixel 106. Column signal processing unit 24 processes the image signal via column signal line 240. The processing in column signal processing unit 24 corresponds to, for example, analog-to-digital (A / D) conversion for converting analog image signals to digital image signals. The image signal processed by column signal processing unit 24 is output as the image signal of imaging element 10.

[0456] The imaging control unit 20 controls the entire imaging element 10. The imaging control unit 20 controls the imaging element 10 by generating and outputting control signals for controlling the line drive unit 22 and the column signal processing unit 24. The control signals generated by the imaging control unit 20 are transmitted to the line drive unit 22 and the column signal processing unit 24 via signal lines 200 and 202, respectively.

[0457] Imaging element 10 may include a black reference pixel region (not shown) for outputting optical black as a black level reference. The black reference pixel region is covered by a light-shielding film such as metal and is typically arranged outside the effective pixel region.

[0458] The imaging element construction examples disclosed herein can be applied to rear-surface illumination imaging devices, front-surface illumination imaging devices, imaging devices using organic photoelectric conversion films, etc.

[0459] [pixel]

[0460] Figure 6 This is a view schematically illustrating an example of a pixel according to this embodiment. For example, an example of a rear-surface illumination type imaging element is shown as pixel 102. Figure 6 It is along Figure 4 A cross-sectional view taken from BB. Pixel 102 includes a lens 104, multiple sub-pixels 106, a light-shielding wall 108, multiple photoelectric conversion element isolation sections 110, a semiconductor substrate 300, a wiring layer 302, wiring 304, an interlayer film 306, and an adhesive layer 308.

[0461] Furthermore, in the figures described later, shaded lines are used in principle, but for ease of understanding, these shaded lines will be used as examples in the explanation. For instance, the photoelectric conversion element isolation section 110 may be shown as an insulator, but the entire photoelectric conversion element isolation section 110 is not necessarily constructed as an insulator.

[0462] As an example, the photoelectric conversion element isolation section 110 includes a metal or the like as a core, and has an insulating film (oxide film) between the core and the semiconductor layer. Characteristic structures are shown in each embodiment described below, and... Figure 6 The cross-sectional view of pixel 102 in each of these featured embodiments includes structural elements of conductive pairs, semiconductors, and insulators. That is, in the cross-sectional view of pixel 102, the material is not limited by the shaded lines.

[0463] As another example, lens 104 and interlayer film 306, etc., do not have shaded lines to transmit light, but this could include, for example, an insulator. As mentioned above, shaded lines can be omitted based on light transmission properties, etc., but it should be noted that, according to the description in this specification, physical properties, etc., appropriately correspond to the accompanying drawings.

[0464] Furthermore, in these figures, for ease of understanding, the dimensions of the photoelectric conversion element isolation section 110 are emphasized, but the actual dimensions relative to the sub-pixel 106 are not shown. That is, regardless of the ratios in these figures, the photoelectric conversion element isolation section 110 can be formed to be sufficiently smaller than the sub-pixel 106.

[0465] Pixel 102 has multiple sub-pixels 106.

[0466] Multiple sub-pixels 106 are set for a single pixel 102. For example, as follows: Figure 4 As shown, 5×5=25 subpixels 106 can be set for a single pixel 102. Subpixels 106 can be, for example, photodiodes. The number of subpixels 106 is not limited to this and can be more or less than 25, as long as appropriate processing can be performed.

[0467] As described below, all sub-pixels 106 are shown as identical squares, but are not limited to this, and may have appropriate shapes depending on various circumstances and the information desired to be obtained. Furthermore, another filter may be used for each sub-pixel 106 included in pixel 102.

[0468] Sub-pixel 106 includes, for example, an n-type semiconductor region and a p-type well region surrounding the n-type semiconductor region. When the pn junction between the n-type semiconductor region and the p-type well region is irradiated by incident light, photoelectric conversion occurs. The charge generated by photoelectric conversion is converted into an image signal by a pixel circuit (not shown). Figure 5 The semiconductor regions of the line drive unit 22, the column signal processing unit 24, and the imaging control unit 20 shown can be further formed on the semiconductor substrate 300.

[0469] In the above description, n-type and p-type have been illustrated, but the semiconductor types used in this invention are not limited to these. For example, n-type and p-type can be interchanged with appropriate operation. Furthermore, for example, n+ type, n++ type, p+ type, p++ type, etc., can be used with appropriate operation. This also applies to the following description.

[0470] For example, a lens 104 is provided for one pixel 102. Furthermore, lens 104 may include multiple stacked lenses. For example, as... Figure 6As shown, lens 104 can be a spherical lens or a lens with a shape close to a sphere. Lens 104 may include, for example, organic materials, such as styrene-based resins, acrylic resins, styrene-acrylic copolymer resins, or siloxane resins. Furthermore, lens 104 may also include inorganic materials, such as silicon nitride or silicon oxynitride. Antireflective coatings with different refractive indices can be formed on the lens surface.

[0471] Furthermore, for the height difference of the lower layers, lens 104 may include, for example, a planarization film beneath the lens material, which comprises an organic material such as acrylic resin. As another component, lens 104 may include a transparent inorganic material such as silicon oxide planarized by chemical mechanical polishing (CMP). Additionally, lens 104 may be a reflow lens formed by a reflow process.

[0472] Figure 6 An example of a rear-surface illumination type imaging element 10 is shown, and the cases of beams incident from a third direction in a direction parallel to the element mounting (parallel to the optical axis of lens 104) and in an oblique direction (not parallel to the optical axis of lens 104) are also shown.

[0473] For example, a parallel beam of light (solid line) incident from the top of lens 104 converges onto sub-pixel 106 located at the center. Simultaneously, a beam of light incident along an oblique direction (dotted or dashed line) converges onto sub-pixel 106 located outside the center. Note that in the above description, the vertical optical axis of lens 104 is used as a reference, but this is not always the case. The direction from which the beam of light enters onto sub-pixel 106 located at the center of pixel 102 can also be determined using techniques such as pupil correction described below.

[0474] Note that details of another form of optical path will be explained below.

[0475] The light-shielding wall 108 isolates the pixels 102 from each other. The light-shielding wall 108 can suppress the incidence of light from adjacent pixels 102 and can block stray light by setting the light-shielding wall 108. Therefore, crosstalk that may occur in adjacent pixels 102 can be suppressed and the resolution can be improved.

[0476] The light-shielding wall 108 may include a light-shielding material, such as a metal film comprising at least one of tungsten (W), aluminum (Al), silver (Ag), gold (Au), copper (Cu), platinum (Pt), molybdenum (Mo), chromium (Cr), titanium (Ti), nickel (Ni), iron (Fe), and tellurium (Te), a composite comprising at least two of these metals, an oxide of these metals, a nitride of these metals, or an alloy of these metals. Furthermore, multilayer films obtained by combining these materials can also be constructed.

[0477] Additionally, as described below, the light-shielding wall 108 can also be divided into multiple segments in a third direction. At the boundary of the pixel 102, the light-shielding wall 108 and the photoelectric conversion element isolation section 110 can be in continuous contact with each other.

[0478] The photoelectric conversion element isolation section 110 isolates the plurality of sub-pixels 106 included in the pixel 102. That is, the photoelectric conversion element isolation section 110 is configured such that the influence of incident light does not reach another sub-pixel 106 between adjacent sub-pixels 106.

[0479] The semiconductor substrate 300 is, for example, a silicon substrate. Semiconductor regions constituting elements of a pixel circuit are formed in the semiconductor substrate 300. The elements of the pixel circuit are formed in well regions formed in the semiconductor substrate 300. As an example, the semiconductor substrate 300 in the figures includes a p-type well region.

[0480] Wiring layer 302 connects the semiconductor elements in pixel 102 to each other. Furthermore, wiring layer 302 is also used for connections to circuitry outside the pixel and forms signal lines. The wiring in wiring layer 302 forms wiring 304, which uses conductors made of metals such as copper or aluminum to transmit electrical signals, and the insulating layer includes, for example, silicon oxide (SiO2) to insulate the wirings from each other.

[0481] In the case of the rear-surface illumination type imaging element 10, the insulating layer and wiring 304 are formed adjacent to the front surface side of the semiconductor substrate 300 to form the wiring layer 302. Furthermore, a support substrate (not shown) may be arranged adjacent to the wiring layer 302. The support substrate is the substrate that supports the imaging element 10 and improves its strength during the manufacture of the imaging element 10. Logic circuits, etc., may be pre-mounted on the support substrate, and the circuits of the semiconductor substrate 300 and the support substrate may be electrically connected to each other.

[0482] An interlayer film 306 is disposed on the metal film 316 to, for example, cover the sub-pixel 106 and the photoelectric conversion element isolation portion 110. The interlayer film 306 may include a transparent material, such as silicon oxide, silicon nitride, or SiON.

[0483] Note that in the accompanying drawings, shaded lines have been omitted for ease of observation, but appropriate conductors, semiconductors, and insulators are arranged. Without forming a light-shielding wall 108, organic materials such as styrene-based resins, acrylic resins, styrene-acrylic copolymer resins, or siloxane resins can be used, and the lens 104 can be directly mounted on the organic material.

[0484] As described below, an inner lens may also be provided in the interlayer film 306 (i.e., between the lens 104 and the sub-pixel 106). Alternatively, a light-shielding wall 108 penetrating the interlayer film 306 may be provided at the boundary between pixels 102.

[0485] An adhesive layer 308 is disposed between the interlaminar film 306 and the lens 104. The adhesive layer 308 is used to planarize the interlaminar film 306 and to bring the interlaminar film 306 and the lens 104 into close contact with each other. The adhesive layer 308 comprises, for example, a transparent organic material with adjustable viscosity, more specifically, an acrylic resin or an epoxy resin.

[0486] Figure 7 This is a schematic cross-sectional view showing the sub-pixel 106 and the photoelectric conversion element isolation portion 110 according to the embodiment in more detail. In this figure, the proportions are significantly different from the actual proportions of the sub-pixel 106 because the photoelectric conversion element isolation portion 110 is emphasized.

[0487] The photoelectric conversion element isolation section 110 may include a p-type well region 310.

[0488] The photoelectric conversion element isolation portion 110 is formed, for example, from a fixed charge film 312, an insulating film 314, and a metal film 316 in the well region 310 of the semiconductor substrate 300. As described above, the photoelectric conversion element isolation portion 110 is disposed in a trench formed in the semiconductor substrate 300 so as not to propagate information about light intensity to adjacent sub-pixels 106.

[0489] An insulating film 314 can be disposed in the trench. In addition to the insulating film 314, a metal film 316 can also be disposed. A fixed charge film 312 with a negative fixed charge can be disposed on the sidewall of the trench between the light receiving surface of the semiconductor substrate 300 and the isolation section 110 of the photoelectric conversion element.

[0490] Because the pinning effect of the negative charge film 312 is enhanced by the inversion layer generated on the contact surface of the semiconductor substrate 300, the generation of dark current is suppressed. The negative charge film 312 is, for example, an insulator and may include oxides or nitrides comprising at least one of hafnium (Hf), zirconium (Zr), aluminum, tantalum (Ta), and titanium.

[0491] The insulating film 314 contains, for example, silicon oxide, and insulates the photoelectric conversion element of the sub-pixel 106 from the metal film 316.

[0492] The metal film 316 has an opening in at least a portion of the sub-pixel 106. Furthermore, the metal film 316 can be embedded in the gap of the insulating film 314 in the trench portion of the photoelectric conversion element isolation portion 110.

[0493] The metal film 316 can block light to cover the black reference pixel area and the peripheral circuit area. The metal film 316 can include a light-blocking material, such as a metal film containing at least one of metals such as tungsten, aluminum, silver, gold, copper, platinum, molybdenum, chromium, titanium, nickel, iron, and tellurium, a composite of these metals, an oxide of these metals, a nitride of these metals, or an alloy of these metals. Furthermore, these materials can be combined into a multilayer film. Additionally, considering the process differences in linewidth and the misalignment between the light-blocking wall 108 and the metal film 316, the remaining width of the metal film 316 at the boundary of pixel 102 can be set to be greater than the remaining width of the metal film 316 at locations outside the boundary of pixel 102.

[0494] The remaining width of the metal film 316 in the photoelectric conversion element isolation section 110 can be greater than or less than the width of the trench formed in the semiconductor substrate 300. In the former case, dark current and white point characteristics are suppressed, and angular resolution is improved. In the latter case, sensitivity is improved. Furthermore, in a portion of the photoelectric conversion element isolation section 110 included in the pixel 102, the metal film 316 can be disposed only in the gaps of the insulating film 314 in the trench portion, and the metal film 316 may not be disposed above the surface of the insulating film 314.

[0495] Note that in the following explanation, when in conjunction with Figure 6 In partial or full sectional views of the same pixel 102, sometimes the following is omitted. Figure 7 The structural elements shown in the description are not readily apparent from the accompanying drawings, but unless otherwise stated, pixel 102 has a similar structure. For example, the photoelectric conversion element isolation section 110 has a fixed charge film 312, an insulating film 314, and a metal film 316 between the sub-pixel 106 and the photoelectric conversion element isolation section 110. Similarly, the same applies between the sub-pixel 106 and the interlayer film 306.

[0496] Signal Processing

[0497] The column signal processing unit 24 outputs an analog signal from the pixel 102 formed as described above, and further performs appropriate signal processing on the analog signal.

[0498] Figure 8 An example block diagram relating to signal processing in electronic device 1 according to an embodiment is shown. Display unit 2, optical system 9, and imaging element 10 are shown for reference, but are not limited to this configuration. For example, circuitry performing various display signal processing can be connected to display unit 2. Furthermore, a control unit for comprehensive control of electronic device 1 can also be provided.

[0499] As in Figure 1 The electronic device 1 shown includes, for example, Figure 8The electronic device 1 may include a display unit 2, but this embodiment is not limited to this. That is, the electronic device 1 may not include a display unit 2.

[0500] Imaging element 10 can receive light via optical system 9, which includes an optical lens for controlling incident light. Furthermore, imaging element 10 can receive light from a subject without an optical lens. Imaging element 10 can receive reflected light emitted from a light source inside the housing onto the finger, transmitted or scattered light emitted from a light source outside the housing onto the finger, or transmitted or scattered light from the finger due to ambient light.

[0501] exist Figure 8 In this electronic device 1, a signal processing unit 40, a storage unit 42, an image processing unit 44, an authentication unit 46, and a result output unit 48 are included as structural elements for processing signals, etc. Although the imaging element 10 is... Figure 8 While these elements are shown as separate components, they may be included within the imaging element 10, and the imaging element 10 may perform each of the functions described below. These structural elements may be located, for example, on the same chip as the imaging element 10, on another stacked chip, or on other chips.

[0502] The signal processing unit 40 converts the analog signal output from the imaging element 10 into a digital signal and outputs the digital signal. Furthermore, the signal processing unit 40 appropriately processes the converted digital signal and converts it into image data. During this conversion, the signal processing unit 40 performs signal processing required to generate the image data, such as ground correction and pixel correction. For example, the signal processing unit 40 can perform signal processing such as ground correction and pixel correction. Figure 5 The column signal processing unit 24 described herein is configured as part of the signal processing unit 40.

[0503] Storage unit 42 stores data required for processing by electronic device 1. Storage unit 42 temporarily stores, for example, image data output from signal processing unit 40 or other components. In addition, when information processing of software for at least one structural element in electronic device 1 is specifically implemented using hardware resources, storage unit 42 may store programs related to the software, and the corresponding structural element can perform processing by reading the programs stored in storage unit 42.

[0504] The image processing unit 44 performs image processing on the image data output from the signal processing unit 40. For example, this image processing may include conversion processing to an image suitable for recognition, or, in the case of a fingerprint image, processing of data other than the image itself. The image processing unit 44 may perform, for example, de-mosaic processing, color correction processing, etc.

[0505] Note that the signal processing unit 40 and the image processing unit 44 do not need to be strictly distinguished, and the data input / output direction may not be the same. For example, the signal processing unit 40 and the image processing unit 44 may be constructed as the same element. As another example, each of the signal processing unit 40 and the image processing unit 44 may perform processing suitable for the architecture constituting that element. The detailed operation and function of each construction will be described in the following embodiments.

[0506] The authentication unit 46 performs personal authentication, for example, based on the fingerprint shape (feature points) output from the addition processing unit, etc. Personal authentication can be performed not only on the fingerprint shape, but also on the location information of sweat glands scattered on the surface of the finger at a size of approximately 30 μm.

[0507] For example, authentication unit 46 can perform biometric authentication or personal authentication based on the spectral analysis results analyzed by signal processing unit 40 and the like, utilizing the rising spectrum shape of the skin color spectrum.

[0508] When the signal processing unit 40 detects spectral features from a vein, the authentication unit 46 can use the data regarding the spectral features to confirm that the subject in contact with the reading surface 12 is a living body. Furthermore, this authentication can be performed in combination with authentication related to vein shape. Authentication regarding artery shape will be described in the embodiments described below.

[0509] For example, personal information can be stored in the authentication unit 46 as fingerprints or sweat gland feature points, or it can be stored in the storage unit. The stored information can be information about the spectrum or information about shape, such as fingerprints. When the subject is in contact with the reading surface 12, the authentication unit 46 can determine that the subject is a living finger and can authenticate that the subject is the stored individual.

[0510] The result output unit 48 outputs a personal authentication result based on the result output from the authentication unit 46. For example, the result output unit 48 may output an authentication success signal if the finger in contact with the reading surface matches the recorded personal data, or it may output an authentication failure signal in other cases.

[0511] For the electronic device 1 according to this embodiment, the case of performing personal authentication using, for example, fingerprints will be described. In this case, the electronic device 1 can further perform spectral determination of the rise of veins and skin as an anti-spoofing measure.

[0512] Note that the authentication method described in this embodiment is not limited to this combination, and the electronic device 1 may, for example, make a determination solely based on fingerprint shape and the spectrum specific to skin. Alternatively, it may make a determination solely based on fingerprint shape and the spectrum specific to veins. Furthermore, it may make a determination solely based on fingerprint authentication or a combination of all authentication methods. That is, the electronic device 1 may perform authentication using a method that includes at least one of various authentication methods.

[0513] Furthermore, another authentication method (such as facial authentication, password input authentication, etc.) can be combined with the authentication method according to this embodiment, and these authentication methods are not excluded, wherein facial authentication is performed based on the position of facial feature points (such as eyes, nose, or mouth) or the position or size of facial regions.

[0514] Furthermore, the combination can be used selectively depending on the purpose of the electronic device 1. For example, the electronic device 1 can reduce processing time by using fingerprint authentication to unlock the lock screen, and in cases requiring high authentication accuracy, such as financial transactions, biometric authentication can be performed using spectral information (skin color spectrum and vein spectrum) in addition to fingerprint authentication.

[0515] Figure 9 This is a flowchart illustrating the processing flow of electronic device 1 according to an embodiment.

[0516] First, the electronic device 1 activates the sensor (S100). For example, when the electronic device 1 activates the sensor, it can be in a standby state by energizing the aforementioned structural elements. The electronic device 1 can explicitly activate the sensor using a switch or the like. As another example, the electronic device 1 can optically or mechanically acquire contact between the subject and the reading surface 12, and use this acquisition as a trigger to activate the sensor. As yet another example, the electronic device 1 can be triggered by detecting that a finger has approached the reading surface 12 at a distance less than a predetermined distance.

[0517] Next, the signal processing unit 40 detects the intensity of the light incident at the time of information acquisition based on the information acquired from the imaging element 10, and acquires the external light conditions based on the detection result (S102). For example, the electronic device 1 acquires an image in a state where no light from the inside is incident. Through this acquisition, the intensity of sunlight, light from an indoor light source passing through the finger, or light entering from the gap between the fingers is detected. The signal processing unit 40 can perform grounding processing in a later processing based on the light intensity. The acquisition of the external light image for grounding processing can be performed before or after the fingerprint image acquisition, or at both times.

[0518] Next, the light-emitting unit disposed in the electronic device 1 emits light to illuminate at least a portion of the area where the finger and the reading surface 12 are in contact with each other (S104). The light emitted can be white light or light with a specific wavelength, such as light of R, G, B, etc. In the following text, when referring to colors, red can be simply referred to as R, green as simply referred to as G, and blue as simply referred to as B.

[0519] For example, since light from the longer wavelength side passes through the finger, B (and G) light can be emitted to obtain the surface shape. To analyze the reflectance spectrum of human skin surfaces, R (and G) light can be emitted. Furthermore, R (and near-infrared) light can be emitted to observe veins. In this way, the emitted light can be tailored to produce an appropriate color based on subsequent processing.

[0520] These lights do not need to be emitted simultaneously. For example, B and G can be emitted first to obtain data for fingerprint shape analysis, then R can be emitted to obtain data for spectral analysis, and then red to near-infrared light can be emitted to obtain data for vein authentication analysis. Note that the processing in S104 is not necessary when acquiring light reception information from external light sources.

[0521] Next, the imaging element 10 receives light containing information such as fingerprints emitted by the light-emitting unit and reflected on the reading surface 12 (S106). The light reception is performed by the imaging element 10, and then the necessary subsequent processing is performed. For example, based on the intensity of the light received by the light-receiving unit of the sub-pixel 106, an analog signal is output from the imaging element 10 (imaging device 3) through a photoelectric conversion element.

[0522] Next, the signal processing unit 40 and / or the image processing unit 44 perform appropriate processing on the received light data (S108). For example, after light reception, the signal processing unit 40 and the image processing unit 44 perform processing to obtain the fingerprint shape, obtain spectral information of reflected light, scattered light, or transmitted light, or calculate the offset between sub-pixel images and synthesize sub-pixel images through A / D conversion and background correction.

[0523] Next, the authentication unit 46 determines whether the fingerprint shapes match each other (S110). The fingerprint shape determination can be performed using general methods. For example, the authentication unit 46 extracts a predetermined number of feature points from the fingerprint and determines whether the fingerprint can be identified as belonging to the stored individual by comparing the extracted feature points.

[0524] If the fingerprint shapes do not match (S110: No), the electronic device 1 repeats the process that started from S102. In the case of repeated processing, the process can be modified as follows. For example, since the position of the finger is unclear, the light-emitting unit initially causes the display unit to emit light over a wider area. However, in the second and subsequent authentications, information such as the area where the finger to be authenticated exists can be acquired in the external light condition acquisition process (S102), and the light-emitting area for the second and subsequent authentications can be controlled. Therefore, noise light is reduced and authentication accuracy is improved.

[0525] Furthermore, electronic device 1 can perform second and subsequent authentications while changing the light source conditions. Additionally, electronic device 1 can perform second and subsequent authentications by switching the processing methods, such as signal processing, image processing, or authentication algorithms, within signal processing unit 40 or image processing unit 44. When processing is repeated in this manner, even if the luminous area is reduced based on the image information from the first authentication, operation can continue without outputting error messages, thus keeping the user's finger in place.

[0526] If the fingerprint shapes match (S110: Yes), the authentication unit 46 determines that the authentication is successful (S112) and outputs the authentication result from the result output unit 48. In this case, the result output unit 48 outputs, for example, information indicating successful authentication and allows access to another configuration of the electronic device 1.

[0527] Furthermore, in the above description, the result output unit 48 performs output if successful, but the present invention is not limited thereto.

[0528] Furthermore, the above process can be repeated in the event of authentication failure, but if the process is repeated a predetermined number of times, access to electronic device 1 can be blocked without performing authentication. In this case, the user can be prompted to enter a password via another access component (e.g., a numeric keypad) from the interface.

[0529] Furthermore, in this situation, the device reading may fail, so the authentication process can be repeated while changing the state of the light emission, light reception, the reading surface, the spectrum being used, etc. For example, if the analysis results show that the device is wet, some output can be provided to the user through the interface to wipe the water off and perform the authentication operation again.

[0530] As described above, according to this embodiment, for light converged by an array of on-chip lenses, the imaging device 3 of the electronic device 1 can isolate and measure the intensity of light incident from multiple different angles while suppressing stray light. As described below, these measurements can provide color information or spectral information to each photoelectric conversion element by combining color filters or plasma filters.

[0531] Furthermore, the electronic device 1 can have a personal authentication function, and this personal authentication function can achieve fingerprint authentication without the need for an optical lens. For example, information can be obtained from sub-pixels 106 at different angles without requiring an optical system with a pinhole or the like. Therefore, the electronic device 1 can acquire images captured with higher sensitivity and suppress resolution degradation, and can achieve high-precision authentication by using the images for authentication.

[0532] The global shutter drive of the imaging device 3 is certified by a flip operation performed using the global shutter as described below.

[0533] When performing vein authentication as described below, enable 3D vein authentication.

[0534] The rise spectrum specific to skin color can be measured using various filters described below. Additionally, depending on the type of filter, biometric measurements such as pulse rate or saturated oxygen concentration can be performed. These features enable enhanced personal authentication against impersonation.

[0535] The various configurations of each structural element will be explained below. First, the optical receiving aspect of electronic device 1 will be used as an example.

[0536] (Second Embodiment)

[0537] Figure 10 This is a schematic view illustrating an example of the imaging state of the imaging element 10. Similar to a smartphone or tablet, Figure 10 The electronic device 1 shown includes a display as a display unit 2. For example, the electronic device 1 includes an imaging element 10 located below the display as the display unit 2. Figure 1 As shown, the display unit 2 may include a touch panel 6, and may include an input interface through which input can be performed by touching the touch panel with a finger or the like.

[0538] The electronic device 1 can emit light toward the reading surface 12 by emitting light from the display unit 2 disposed inside the electronic device 1. More specifically, the light-emitting element included in the display unit 2 can emit light toward the finger. The imaging element 10 can receive light reflected or scattered from or near the reading surface 12 due to reflection, scattering, etc.

[0539] like Figure 10 As shown, the readable area can be set within the range where the imaging element 10 can receive light. In this case, the light-emitting element of the display unit 2 can emit light in the area where the imaging element 10 can receive reflected light from the reading surface 12, etc.

[0540] Figure 11 This is a view schematically illustrating another example of the imaging state of the imaging element 10. (See image below.) Figure 11 As shown, the light-emitting area of ​​the display unit can be adjusted appropriately. For example, the electronic device 1 can narrow the light-emitting area to be only near the finger placement area. Similarly, the imaging element 10 can also be controlled to acquire a signal in an area where the imaging element can receive reflected light from the reading surface 12 that is in contact with the finger.

[0541] like Figure 10 and 11 As shown, when an area to be authenticated is set on the reading surface 12, a guide display can be executed to prompt the user to place their finger on that area of ​​the display unit 2. This display can be preset based on the imaging device 3 and the position of the light-emitting pixels that emit light at the time of imaging.

[0542] Figure 12 This is a schematic view illustrating the reflection and scattering of light near the reading surface 12. (See image.) Figure 12 As shown, the light-emitting element disposed in the display unit 2 emits light, and the light emitted by the light-emitting element is reflected or scattered on or near the reading surface 12. The imaging element 10 receives the reflected or scattered light, converts the reflected or scattered light into an analog signal, and outputs the analog signal.

[0543] Note that, for ease of understanding, Figure 12 The light-emitting element is shown in a shape similar to a light-emitting diode, but the light-emitting element may not actually have this shape, and may be, for example, an OLED for emitting light in a display (display unit 2) formed on a semiconductor substrate.

[0544] For example, light emitted from the light-emitting element is well reflected and propagated to the imaging element 10 in areas where the finger ridge does not contact the reading surface 12. On the other hand, in areas where the finger ridge contacts the reading surface 12, for example, a portion of the light emitted from the light-emitting element is transmitted into the interior of the finger, and the reflected or scattered light inside the finger propagates through the reading surface 12 to the imaging element 10.

[0545] For example, in such Figure 12 In this propagation scenario, the photoelectric conversion element in the imaging element 10 that receives light reflected in the region where the finger ridge and the reading surface 12 are in contact, and the photoelectric conversion element that receives light reflected in the region where the finger ridge and the reading surface 12 are in contact, receive light of different intensities.

[0546] Imaging element 10 and / or signal processing unit 40, etc., can reconstruct an image of the fingerprint based on the intensity of the received light. For example, as described below, signal processing unit 40, etc., can also remove unwanted reflections from elements used in the display based on analog signals acquired for each sub-pixel 106. As described above, electronic device 1 can acquire an image with unwanted noise removed by imaging device 3 including sub-pixels 106.

[0547] Furthermore, the imaging device 3 can acquire signals captured after the display unit 2 emits light and signals captured when the display unit 2 is not emitting light. The imaging device 3 can switch the light emission state of the display unit 2 and acquire images, and the signal processing unit 40 or the image processing unit 44 can acquire difference images between these images. By acquiring difference images, the electronic device 1 can acquire images that suppress the effects of external optical noise.

[0548] Furthermore, for example, the imaging element 10 can decompose the wavelengths of light that have diffused from the area where the fingerprint ridges and the reading surface 12 have come into contact and propagated into the finger and returned to the electronic device side, and acquire spectral information specific to human skin, etc.

[0549] Furthermore, taking advantage of the fact that light in the red to near-infrared region is more readily absorbed in the presence of veins or arteries than in the absence of blood, the imaging element 10 can acquire spectral information (and shape) related to veins and arteries.

[0550] As described above, according to this embodiment, the electronic device 1 emits light from a light-emitting element arranged on the display surface of the display unit 2, receives the light reflected and scattered near the reading surface 12 using the imaging element 10, and acquires an analog signal. Through this acquisition, personal authentication can be performed using the light-emitting element provided for the display of the electronic device 1.

[0551] As described above, the electronic device 1 may include an imaging device 3 located below the display. The electronic device 1 can then remove unnecessary images from the display element positioned directly above it by synthesizing sub-pixel images, and can extract only the original subject image. Furthermore, the electronic device 1 can remove the effects of external light noise by continuously acquiring images captured when the display is illuminated and images captured when it is not illuminated, and generating a difference image.

[0552] (Third Embodiment)

[0553] Figure 13 This is a view schematically illustrating another example of the imaging state of the imaging element 10. The electronic device 1 includes a light source 14, which is different from the display, within its housing.

[0554] Light source 14 is arranged in electronic device 1 and is a different light source from the light-emitting element used for display on the display of display unit 2. Light source 14 is, for example, positioned below protective glass 7. For example, when performing authentication using imaging element 10, light source 14 emits light to be imaged by imaging element 10. Light source 14 can be, for example, OLED, microLED, microOLED, etc., but is not limited to these, and can be any light source that can appropriately emit light.

[0555] Electronic device 1 can emit light from light source 14 toward reading surface 12 and receive the returned light through imaging element 10. As in the above embodiment, electronic device 1 can be a device such as a smartphone. In this case, with... Figure 10 Similarly, the imaging device 3 may include an imaging element 10 located below the display unit 2 (i.e., below the display).

[0556] Furthermore, as another example, the electronic device 1 may include an imaging element 10 and a light source 14 in a configuration that does not include a display. For example, also in an electronic device 1 such as a smartphone that includes a display (display unit 2), at least one of the imaging element 10 and the light source 14 may be located in an area not below the display, such as in an area where a lens unit or a speaker unit with a front-facing camera is located.

[0557] Similar to Figure 12 According to this embodiment, the electronic device 1 can acquire fingerprint information by reading the areas where fingerprint ridges exist and the areas where fingerprint ridges do not exist for each pixel. Furthermore, the electronic device 1 can use the imaging element 10 to decompose the light that has been scattered and propagated into the finger and then returned to the electronic device side (e.g., Figure 3 The wavelength of R3 in the image is determined, and spectral information specific to human skin is obtained. An advantage of this embodiment is that it provides a light source specification specifically designed for authentication purposes.

[0558] Furthermore, in fingerprint shape measurement, it is desirable to receive the total internal reflection component due to the refractive index difference between the reading surface 12 and the air layer. For example, the electronic device 1 can display the contact area of ​​the finger on the reading surface 12 to satisfy the condition that the light totally reflected by the reading surface 12 from the light source 14 can be received by the imaging element 10.

[0559] Figure 14 This is a view schematically illustrating another example of the imaging state of the imaging element 10. Of course, in Figure 11 This can also be used to deal with such areas under certain circumstances.

[0560] As described above, the light source used during imaging may not be a light-emitting element used for display on the display unit 2. Note that, as described in this embodiment, the electronic device 1 may not include the display unit 2.

[0561] (Example 4)

[0562] Figure 15 This is a view schematically illustrating an example of the imaging state of the imaging element 10. The electronic device 1 includes a light source 16, such that light is incident on a finger or the like, approximately parallel to the protective glass 7. The imaging element 10 can receive light emitted from the light source 16 and reflected, scattered, etc., near the reading surface 12.

[0563] The light source 16 is configured to emit light in a direction parallel to the arrangement direction of the protective glass 7. The imaging element 10 then receives the light reflected or scattered by fingers or the like near the reading surface 12. Although not shown in the figure, it is understood that... Figure 3 As shown, the imaging element 10 can receive light reflected from a finger at the upper side of the reading surface 12 (i.e., the outside of the electronic device 1).

[0564] As described above, according to this embodiment, authentication can be performed using scattered light from inside the subject (e.g., a finger), thus enabling robust authentication against sweat, dryness, etc.

[0565] (5th embodiment)

[0566] Figure 16 This is a schematic view illustrating an example of the imaging state of the imaging element 10. The electronic device 1 includes a light source 16 that allows light to pass through the interior of the protective glass 7.

[0567] The light source 16 is arranged to propagate light through total internal reflection using a protective glass 7 as a light guide. A portion of the light emitted from the light source 16 is emitted through the interior of the protective glass 7 and enters the subject. The imaging element 10 can then receive the scattered light emitted from the reading surface 12.

[0568] That is, the light source 16 is configured such that the emitted light enters the protective glass 7 and propagates within the protective glass, which serves as a light guide, while being totally internally reflected due to the difference in refractive index between the protective glass and the air layer. The area where the subject contacts the reading surface 12 has a small difference in refractive index. A portion of this light enters the subject, is scattered, and is emitted towards the imaging element 10 via the reading surface 12. The imaging element 10 receives the emitted light.

[0569] In this embodiment, the protective glass 7 may be formed such that its refractive index varies along a third direction. By forming a protective glass 7 with a varying refractive index, the transmission of light from the outside or light emitted from the inside at a certain angle can be achieved with higher precision without emitting light emitted from the light source 16 to the reading surface 12 and the imaging element 10 side.

[0570] Furthermore, through this formation method, the angle of light changes due to reflection and scattering in the area touched by fingers, etc., so the imaging element 10 can fully receive the light affected by fingers, etc. As described above, total internal reflection can be generated not only on the surface of the protective glass 7 including the reading surface 12, but also through changes in the refractive index within the protective glass 7.

[0571] As described above, according to this embodiment, authentication can be performed using scattered light from inside the subject (e.g., a finger), thus enabling robust authentication against variations in imaging conditions such as sweat and dryness.

[0572] (Sixth Embodiment)

[0573] Figure 17 This is a view schematically showing an example of the imaging state of the imaging element 10. The electronic device 1 includes a light source 18 on the upper side of the reading surface 12 (i.e., the side opposite to the imaging element 10).

[0574] The light source 18 is positioned facing the reading surface 12 through the subject (e.g., a finger). Light emitted from the light source 18 can be transmitted and scattered through the subject and received by the imaging element 10 through the reading surface 12.

[0575] For example, the light source 18 can be configured to be detachable from the electronic device 1. Alternatively, a system can be employed that emits light after the electronic device 1, which is a mobile terminal (e.g., a smartphone equipped with the imaging element 10 of this embodiment), is brought close to the fixed light source 18. Operation commands between the light source 18 and the electronic device 1 can be synchronized and transmitted via wireless communication such as infrared, Bluetooth, Wi-Fi, or near-field communication.

[0576] The light source 18 may be provided with a mold (groove) shaped to easily fix a subject (e.g., a finger). In addition, a clamp capable of fixing the electronic device 1 in a predetermined position may be provided.

[0577] The electronic device 1 can be positioned close to the light source 18 while maintaining direct contact between the subject (e.g., a finger) and the electronic device. In this case, communication, infrared detection, etc., can be performed between the electronic device 1 and the light source 18, and the light source 18 can emit light, for example, when the electronic device 1 is detected approaching a predetermined position. Then, synchronized with the light source 18 via wireless communication, the electronic device 1 can receive reflected or scattered light through the imaging element 10. The detection element can be a physical contact button or a sensor for sensing the electronic device 1 or the subject. Furthermore, signals transmitted from the electronic device 1 can be received at the light source 18, and light can be emitted thereas as well.

[0578] As described above, the electronic device 1 according to the third to sixth embodiments has some forms in which a light source different from that of the display unit is provided. In these embodiments, the imaging element 10 may be disposed below the display, or the display may not be disposed between the protective glass and the imaging element. The embodiments described herein are not mandatory, and the electronic device 1 may use natural light, such as sunlight, as a light source.

[0579] As described in embodiments two through six, the light source emitting light onto the subject can be an organic EL display emitting red, blue, and green light, or an organic EL display emitting white light and including color filters for color development. Alternatively, the light source can be a liquid crystal display or a light-emitting diode (LED).

[0580] In addition, laser diodes (LDs) can be used as the light source. An LD can be, for example, a vertical-cavity surface-emitting laser (a so-called VCSEL), which resonates light in a direction perpendicular to the substrate surface and emits light in a direction perpendicular to the surface, within a structure comprising a stacked semiconductor or a dielectric in a mirror. Phosphorescent materials (e.g., ZnS containing rare-earth ions such as Yb³⁺, Tm³⁺, or Nd³⁺ at the luminescent center) can be used. Furthermore, quantum dots such as GaAs or InGaAs can be used.

[0581] The types of light sources are not limited to the examples listed above. It is expected that the light source used for certification will have appropriate intensity in the wavelength region corresponding to each testing objective.

[0582] As an example, in the case of fingerprint authentication, a light source outputting in the blue to green wavelength region, specifically around 400 nm to 500 nm, is preferably selected. It is generally known that the scattering coefficient of the skin surface and the molar absorption coefficient of melanin depend on the wavelength of light. More specifically, the properties related to scattering and absorption tend to decrease with increasing wavelength. Therefore, for longer wavelengths of light, the effects of scattering and absorption are smaller, and the light penetrates the skin. That is, when imaging skin patterns using long-wavelength light, the light that has already entered the skin is reflected by the tissues within the skin.

[0583] Long-wavelength light can become background light during imaging and may contribute to resolution degradation. Therefore, using short-wavelength light as the light source for skin pattern imaging is effective. For example, in the case of using an organic EL display, both blue and green pixels can emit light, or one of the blue and green pixels can emit light, to serve as the light source.

[0584] For example, in the case of reflection from human skin, there is typically an increase around 590 nm in the wavelength region of approximately 550 nm to 650 nm. Figure 271 The reflectivity of human skin is explained (from "Skincolor", Akihiro OHGA, Television, 1967, Vol. 2, No. 8, pp. 534-540). As shown in the figure, reflectivity increases from 550 to 650 nm, independent of skin color, sunburn, etc. Therefore, for example, to detect the rise in signal intensity in the 500 nm to 700 nm range, a light source with output in this wavelength region is preferred.

[0585] For example, in order to accurately separate Figure 10 The upward trend allows for the separate emission of light from green organic ELs emitting approximately 500nm to 600nm and red organic ELs emitting approximately 600nm to 700nm, and allows for the acquisition of individual images and spectral analysis.

[0586] These light sources do not necessarily have to be composed of a single type of component; they can also be composed of multiple light sources, each with its own unique emission spectrum. For example, both organic ELs that emit visible light and LEDs that emit near-infrared light can be used as light sources.

[0587] Next, the arrangement of pixel 102 and the various filters set in pixel 102 will be explained.

[0588] (Seventh Embodiment)

[0589] In the above embodiments, pixels 102 and sub-pixels 106 are arranged in a rectangular array without gaps along the first and second directions, but the present technology is not limited to this. For example, the shape may not be rectangular, or it may not be arranged along the first and second directions. Furthermore, gaps may exist between pixels.

[0590] Figure 18 This is a schematic view illustrating an example of pixels according to an embodiment. Pixel 102 has 3×3 sub-pixels 106, but is not limited thereto, and is similar to... Figure 4 This can include 5×5 or fewer or more subpixels 106. Additionally, 3×3 pixels 102 are shown, but these pixels 102 obviously represent a portion of the pixel array. The view shown at the bottom is a magnified view of pixel 102.

[0591] like Figure 18 As shown, pixels 102 can be arranged by forming a pixel array along a direction different from the first and second directions of electronic device 1. For example, pixels 102, lens 104, and sub-pixels 106 are arranged in an array by rotating approximately 45 degrees relative to the first and second directions. By arranging pixels 102 in this way, the spacing between pixels 102 can be reduced to 1 / √2, thereby achieving high resolution while maintaining imaging characteristics.

[0592] (Embodiment 8)

[0593] Figure 19 This is a view schematically illustrating an example of pixels according to an embodiment. (e.g.) Figure 19 As shown, pixel 102 may include sub-pixels 106 having a regular hexagonal shape. As another example, pixel 102 may include sub-pixels 106 having a parallelepiped shape. Pixel 102 may have a structure that sets the sub-pixels 106 into a cellular structure.

[0594] Since a regular hexagon has the shortest perimeter among tessellated shapes, it is expected that resolution can be effectively improved by forming subpixels 106 into regular hexagons or similar shapes.

[0595] Furthermore, in the aforementioned light-shielding wall 108 and photoelectric conversion element isolation section 110, stress concentration occurs due to the trenching of the light-shielding wall and photoelectric conversion element isolation section and the embedding of metal or insulating film. Conversely, by forming the pixel 102 into a hexagonal shape with a high stress dispersion effect, the risk of initial failure can be reduced compared to the case including rectangular sub-pixels 106 and pixel 102.

[0596] Furthermore, when the light-shielding wall 108 and the photoelectric conversion element isolation section 110 have an intersection, processing deviations occur in the depth direction due to the micro-load effect during etching. By forming the sub-pixel 106 into a hexagon, the number of joints is reduced to three relative to the four rows of joints in the rectangle, and micro-load processing deviations can be suppressed.

[0597] (Embodiment 9)

[0598] Figure 20 This is a view schematically illustrating an example of pixels according to an embodiment. (e.g.) Figure 20 As shown, subpixels 106A and 106B with different sizes and / or shapes can be set in pixel 102.

[0599] For example, such as Figure 20 As shown, subpixel 106A has a larger area, while subpixel 106B has a smaller area. By comparing these two subpixels, subpixel 106A has a lower angular resolution but higher sensitivity than subpixel 106B. Conversely, compared to subpixel 106A, subpixel 106B has lower sensitivity but superior angular resolution.

[0600] As described above, by mixing subpixels 106 of different sizes, both high-sensitivity and high-resolution subpixel images can be obtained simultaneously. Therefore, for example, by acquiring an image containing pixels with these subpixels 106, a wide dynamic range can be obtained.

[0601] Next, we will explain the case where a color filter is set in each pixel 102.

[0602] In the accompanying drawings used for illustration, for example, nine pixels 102 are shown. These nine pixels are extracted and shown from the pixel array 100. Filters may be disposed over the entire pixel array 100 or over a portion of the pixel array 100. Furthermore, filters with different arrangements may be disposed for each region, rather than over the entire pixel array 100. Additionally, sub-pixels 106 are not explicitly shown in the figures, but naturally, as in each of the embodiments described above, sub-pixels 106 are disposed within pixels 102.

[0603] In the following description of the filter used for pixel 102, the same filter is arranged for pixel 102 which is marked with the same shaded line.

[0604] (Embodiment 10)

[0605] Figure 21 This is a view showing an example of the filters applied to each pixel. Figure 21This is a view illustrating an example of arranging a filter 112 for each pixel 102. The filter 112 is, for example, a color filter and is a filter that extracts light from a predetermined frequency region of the incident light. For example, the filter 112 can be positioned anywhere between the lens 104 and the sub-pixel 106. In the case of a color filter, the filter 112 may comprise an organic film.

[0606] As filter 112, such as Figure 21 As shown, for example, green filter 112G, red filter 112R and blue filter 112B can be arranged in a Bayer array.

[0607] Compared to a color array that combines an on-chip lens, a color filter, and a photoelectric conversion element, this filter arrangement has the advantage of providing angular information to pixel 102 via sub-pixels 106. By arranging the filters according to a Bayer array, an array that takes color reproduction into account can be obtained.

[0608] (Embodiment 11)

[0609] Figure 22 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 22 This is a view showing an example of arranging filters 112 for each pixel 102.

[0610] As filter 112, a green filter 112G, a red filter 112R, a blue filter 112B, and a white (transparent) filter 112W are arranged. This arrangement is an RGBW array, which includes filters 112W for focusing sensitivity in the Bayer array. More specifically, a white light filter 112W is provided for each unit instead of one green filter 112G in the Bayer array.

[0611] Filter 112W can be a filter that allows light to pass through, or it can be omitted depending on its position in the structure, as long as the optical path length is not significantly different from that of other filters. For example, in the structure of pixel 102... Figure 6 In the case of the structure shown and the color filter provided in the interlayer membrane 306, the filter 112W can be provided in an indefinite manner.

[0612] By employing this filter arrangement, an array with improved sensitivity compared to the Bayer array can be obtained.

[0613] (Embodiment 12)

[0614] Figure 23 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 23 This is a view showing an example of arranging filters 112 for each pixel 102.

[0615] As filter 112, a green filter 112G, a red filter 112R, a blue filter 112B, and an infrared filter 112IR are arranged. This arrangement is an RGB-IR array in the Bayer array with an infrared filter 112IR for sensing. More specifically, an infrared filter 112IR is provided for each unit instead of one green filter 112G in the Bayer array.

[0616] By employing this filter arrangement, an array that also receives infrared light can be obtained relative to the Bayer array.

[0617] (Embodiment 13)

[0618] Figure 24 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 24 This is a view showing an example of arranging filters 112 for each pixel 102.

[0619] As filter 112, a green filter 112G, a red filter 112R, a blue filter 112B, and an infrared cutoff filter 112IRC are arranged. This arrangement is an array of infrared cutoff filters 112IRC in the Bayer array. More specifically, an infrared cutoff filter 112IRC is provided for each cell instead of one green filter 112G in the Bayer array.

[0620] This filter arrangement allows for the acquisition of an array that receives infrared light that is also blocked relative to the Bayer array, and in the visible light region, sensitivity can be improved similarly to that of white light.

[0621] (Example 14)

[0622] Figure 25 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 25 This is a view showing an example of arranging filters 112 for each pixel 102.

[0623] As filter 112, a green filter 112G, a cyan filter 112Cy, a magenta filter 112Mg, and a yellow filter 112Ye are arranged. In this embodiment, an array of color filters having a complementary color system will be described.

[0624] For example, when the imaging device 3 is positioned below the display and detects light transmitted through the display, the electronic device 1 may include a polyimide layer between the incident surface (reading surface 12) and the imaging element 10. Typically, it is known that yellow-brown polyimide absorbs light in the blue wavelength region and has high green and red transmittance. Therefore, the imaging element 10 can effectively detect the light intensity and wavelength information from the subject by including pixels 102 equipped with yellow filters.

[0625] (Example 15)

[0626] Additionally, as another example of using visible light filters other than RGB, it is possible to set up filters that can appropriately capture the rising spectrum (500nm to 650nm: see reference) characteristic of human skin. Figure 271 The filter uses green, orange, red, and other colors to adjust the sensitivity of light. Therefore, it can also acquire information such as fingerprints and determine whether light is reflected or scattered by a person's skin, enabling biometric authentication and preventing impersonation. Furthermore, color resolution can be improved by providing four or more colors of filters. In this case, the filter array does not need to be a 2×2 pixel unit.

[0627] The signals obtained from these pixels can be balanced by interpolating each other through subsequent signal processing stages, such as linear matrix or white balance.

[0628] As described above, the imaging device 3 can include various appropriate filters for the pixel 102 according to the information to be acquired, without being constrained by the primary and complementary color systems in visible light.

[0629] (Embodiment 16)

[0630] Figure 26 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 26 This is a view showing an example of arranging filters 112 for each pixel 102.

[0631] like Figure 26 As shown, a single filter 112 can be set for the entire pixel array 100 or a portion thereof.

[0632] By using a single filter 112 in this manner, the imaging device 3 can acquire a signal at the resolution of interest.

[0633] (Embodiment 17)

[0634] Figure 27 This is a view showing an example of the filters applied to each pixel. Similar to... Figure 21 , Figure 27This is a view showing an example of arranging filters 112 for each pixel 102.

[0635] like Figure 27 As shown, two types of color filters 112x and 112y can be arranged in a checkered pattern for the entire pixel array 100 or a portion thereof.

[0636] By using pixels 102 that include two different types of filters, images of different subjects can be acquired. For example, the two types of color filters 112 can be a combination of a filter 112x for visible light and a filter 112y for IR. An example of a checkerboard pattern has been described as an arrangement of the filters, but the arrangement is not limited to this.

[0637] Although not shown, for example, a 2×2 Bayer array could be replaced with another filter 112 (e.g., an IR filter) with a longer period, or as another example, multiple different filters could be arranged in an array filled with a single type of filter. The term "period" is used in these descriptions, but unequal intervals or random arrangements can be used.

[0638] Note that the arrangement of filter 112 is not only applicable to applications such as... Figures 21 to 27 The same rectangular pixel 102 shown, but can also be applied to, for example Figure 19 and 20 Pixel 102 is shown. The filter can be applied to... Figures 21 to 27 The arrangement shown can be made even more unique based on the shape, size, etc. of each pixel.

[0639] Next, the arrangement of filters for sub-pixels 106 in pixel 102, rather than filters for pixel 102, will be described. According to the apparatus of the present invention, filters may also be provided for each sub-pixel 106 instead of for each pixel 102.

[0640] In the following description of the filter used for sub-pixel 106, similar to the case of pixel 102, the same filter is arranged for the same sub-pixel 106 marked with the same shaded line. Furthermore, in the following figures, it is assumed that pixel 102 has 3×3 or 5×5 sub-pixels 106, but the number of sub-pixels 106 is not limited to the aforementioned numbers.

[0641] (Embodiment 18)

[0642] Figure 28A This is a view showing an example of the filters applied to each sub-pixel. Figure 28AThis is a view showing an example of arranging filter 114 for each subpixel 106. In this figure, as an example, one pixel 102 includes 3×3 subpixels 106.

[0643] Pixel 102 includes at least two different types of filters in its sub-pixels 106. A color filter may not be provided for the sub-pixel 106 located at the center of pixel 102. Filters 114 (e.g., color filters) may be provided in the sub-pixels 106 surrounding the sub-pixel 106 located at the center of pixel 102.

[0644] For example, the upper right diagonal sub-pixel 106 can be equipped with a red filter 114R, the horizontal sub-pixel 106 can be equipped with a green filter 114G, and the upper left diagonal sub-pixel 106 can be equipped with a blue filter 114B.

[0645] By setting the color filter in this way, within a pixel 102, brightness information can be accurately obtained in the sub-pixel 106 located at the center of pixel 102 that easily and effectively receives light, and color information can be obtained in the sub-pixels 106 surrounding that sub-pixel 106. Compared to setting a filter for each pixel 102, brightness and color information can be obtained in a well-balanced manner within a single pixel (i.e., in a closer area to the subject).

[0646] Figure 28B This is a view showing an example of the filters applied to each sub-pixel. Figure 28B In the middle, although the array of filters 114 and Figure 28A The array is the same, but pixel 102 includes 5×5 sub-pixels 106. As mentioned above, even in the case of 5×5 pixels, the sub-pixel 106 located in the center and the sub-pixels 106 surrounding it can be similarly configured with different filters.

[0647] Although each sub-pixel 106 in pixel 102 has a different parallax relative to the subject, a composite processing method for offsetting and overlapping the images acquired from the individual sub-pixels 106 can be performed. For example, the offset can be obtained through signal processing so that the overlap is maximized after the images are acquired.

[0648] Furthermore, while maintaining a constant subject distance, the offset can be predetermined, taking into account the sensor's oblique incidence characteristics. The subsequent compositing process can be color reproduction improvement achieved through a general linear matrix or white balance. As another example, the compositing process can be SN improvement achieved by adding identical filter configurations, or an operation to extract wavelengths of a specific spectrum. For instance, these processes can output multiple distinct images, such as a subject image in the visible light region and a characteristic spectral image in the near-infrared region, instead of outputting a single composite image.

[0649] When the offset between the images to be synthesized has a fraction of less than one pixel, a process of aligning the grid by interpolation approximation can be performed. Furthermore, with the same filter, images can be synthesized with this fraction of offset, and images with an increased number of pixels can be temporarily generated. High-resolution images can also be generated by interpolating information using easily manageable equal spacing.

[0650] Part of the parallax image processing will be described in more detail in the following embodiments.

[0651] (Embodiment 19)

[0652] Figure 29 This is a view showing an example of the filters applied to each sub-pixel. For example, similar to... Figure 28A As a filter 114 such as a color filter, the upper right diagonal sub-pixel 106 is provided with a red filter 114R, the horizontal sub-pixel 106 is provided with a green filter 114G, and the upper left diagonal sub-pixel 106 is provided with a blue filter 114B.

[0653] Figure 29 Four pixels 102 are shown. The sub-pixel 106 located at the center of each pixel may not have a color filter, while the surrounding sub-pixels 106 may have a filter 114. The filter 114 is a uniform color filter for each pixel, and the color combination of the filter can be changed between different pixels. As shown, the color arrangement of the color filter can be a primary color array, or it can be an array used when applying other multi-color filters.

[0654] For example, instead of setting it for each pixel 102, it can be set for each sub-pixel 106, corresponding to the configuration described in the above embodiments. Figures 21 to 27 The color filter for pixel 102. That is, the filter set for each pixel 102 may not be determined as filter 112 but as filter 114.

[0655] By setting up such an array, it is possible to obtain brightness information with high precision in the sub-pixel 106 located at the center of pixel 102, which can easily and effectively receive light, and to obtain color information in the sub-pixels 106 surrounding it.

[0656] When only the signal of sub-pixel 106 located at the same position relative to pixel 102 is collected, in order to... Figure 28A The same resolution as pixel 102 in the image obtains the same output under the same conditions, while Figure 29 While the resolution in the image is relatively poor, each sub-pixel outside the center periodically contains multiple outputs with different color conditions and can be individually de-mosaiced.

[0657] (Embodiment 20)

[0658] Figure 30 This is a view showing an example of the filters applied to each sub-pixel. Similar to... Figure 28A As the color filter, the upper right diagonal sub-pixel 106 is provided with a red filter 114R, the horizontal sub-pixel 106 is provided with a green filter 114G, and the upper left diagonal sub-pixel 106 is provided with a blue filter 114B.

[0659] Furthermore, for all pixels 102, vertical sub-pixels 106 are provided with, for example, a yellow filter 114Ye. For example, in the case described above where it is positioned below the display, when polyimide is present between them, the yellow filter 114Ye can effectively sense the light intensity and wavelength information from the subject. As mentioned above, two or more colors of filter 114 can be provided for each pixel 102.

[0660] Note that in the above description, the color filters are red, green, blue, and yellow, but the color filters are not limited to these. Similar to the above embodiment of the filter 112 for the pixel, the sub-pixel 106 may be suitably provided with, for example, a magenta filter 114Mg, a cyan filter 114Cy, a white filter 114W, a filter 114IR for acquiring infrared wavelengths, and a filter 114IRC for blocking infrared wavelengths.

[0661] Additionally, for example, to obtain skin tone characteristics, an orange filter with appropriate sensitivity to light having an ascending spectrum (550nm to 600nm) can be set. In this case, color resolution can be improved by using filters of three or more colors.

[0662] Pixel 102 can be formed by combining a filter 112 applied to pixel 102 and a filter 114 applied to sub-pixel 106. For example, a filter 112IRC for blocking the infrared region can be provided in pixel 102, and filters 114R, 114G and 114B for capturing red, green and blue can be appropriately arranged in sub-pixel 106.

[0663] (Embodiment 21)

[0664] In the above embodiments, the use of a color filter as filter 114 has been described, but filter 114 is not limited to this, and special filters may be used.

[0665] Figure 31 This is a view showing an example of a filter included in sub-pixel 106. The filter is a plasma filter 116. The plasma filter 116 is a filter that selectively transmits specific wavelengths using plasma resonance. By using the plasma filter 116, a narrowband filter that operates through plasma resonance on a metal surface can be realized.

[0666] like Figure 31 As shown, the plasma filter 116 includes a metal film 116A and an aperture 116B. For example, as Figure 31 As shown, the plasma filter 116 is composed of plasma resonance pairs, in which, for example, aperture 116B is arranged in a honeycomb pattern in a thin metal film 116A.

[0667] The metal film 116A is composed of a thin metal film. The metal film 116A can be, for example, a metal film of aluminum, silver, gold, copper, platinum, molybdenum, tungsten, chromium, titanium, nickel, iron, tellurium, etc., a composite of these metals, or an alloy of these metals. These materials can be formed in multiple layers as the metal film 116A.

[0668] The choice of material for a metal film affects the transmission spectrum. For example, aluminum is one of the ideal materials for a wide wavelength range because it reflects all RGB wavelengths and does not absorb anything. Meanwhile, copper readily reflects the red wavelength region and is an ideal material for filters specifically designed for the red or near-infrared wavelength region.

[0669] Each aperture 116B penetrates the thin metal film 116A and serves as a waveguide. Typically, a waveguide has a cutoff frequency and cutoff wavelength defined by its shape, such as side length and diameter, and is designed to prevent light with frequencies equal to or lower than the cutoff frequency (wavelengths equal to or greater than the cutoff wavelength) from propagating. The cutoff wavelength of aperture 116B depends primarily on the aperture diameter D1; the smaller the aperture diameter D1, the shorter the cutoff wavelength. Note that the aperture diameter D1 is set to a value smaller than the wavelength of the light to be transmitted.

[0670] Simultaneously, when light enters a thin metal film 116A having holes 116B formed periodically with short periods less than or equal to the wavelength of the light, a phenomenon occurs where light with a wavelength longer than the cutoff wavelength of the holes 116B is transmitted. This phenomenon is called anomalous plasma transport. This phenomenon occurs when surface plasma is excited at the boundary between the thin metal film 116A and the interlayer film thereon. Therefore, by adjusting the hole spacing a0 and the opening diameter D1 of the holes 116B, information about light of various wavelengths can be selectively acquired.

[0671] Theoretically, plasmon resonance occurs when the dielectric constant εm of the conductor film, the dielectric constant εd of the interlayer film, and the aperture spacing a0 satisfy the following conditions at the surface plasmon frequency ωsp. Here, i and j represent degrees.

[0672] [Mathematical Expression 1]

[0673]

[0674] [Mathematical Expression 2]

[0675]

[0676] Figure 32 This is a graph showing the structure of the aperture 116B in the plasma filter 116 and its wavelength sensitivity. The solid line represents the relationship between wavelength and sensitivity when the aperture spacing a0 = 250 nm, the dashed line represents the relationship when the aperture spacing a0 = 325 nm, and the alternating long and short lines represent the relationship when the aperture spacing a0 = 500 nm.

[0677] Figure 33 It is a graph showing the plasma mode and waveguide mode.

[0678] like Figure 32 As shown, when the aperture spacing a0 increases, the transmission spectrum shifts towards longer wavelengths. Simultaneously, as... Figure 33 As shown, since the spectrum is obtained as a spectrum mixed with waveguide modes of cutoff wavelength or smaller, it is desirable, for example, to stack plasma filters in combination with filter 112 as color filters for pixel 102 to narrow the bandwidth.

[0679] As another example, a plasma filter 116 may include various plasma filters in multiple layers. As yet another example, the plasma filter 116 can obtain multiple spectral outputs and narrow the bandwidth in signal processing.

[0680] As an interlayer film for plasma filters, a film with a low dielectric constant can be used, such as a dielectric or a low-k film, like silicon oxide.

[0681] As described above, by using a plasma filter 116 instead of a color filter, information about light in a predetermined spectral region can be obtained. For example, a plasma filter 116 can be used to replace at least a portion of the embodiments associated with filters. In a third aspect, pixel 102 may combine a color filter and a plasma filter.

[0682] Furthermore, since plasma filters include a metal film, they have the advantage of higher heat resistance than ordinary filters. In the case where the filter is placed before the light-shielding wall is formed, using a plasma filter containing metal as the filter provides the advantage that the light-shielding wall 108 and the like can be manufactured using appropriate processing methods without being limited by thermal brittleness.

[0683] Furthermore, the metal film 316 used for light blocking between pixels 102 or between sub-pixels 106 can comprise the same metal material as the plasma filter 116. Using the same metal material has the advantage of reducing the number of processes. In the case where the metal film 316 also serves as a light-blocking film for the black reference pixel area, the required film thickness for light blocking may differ from the optimal film thickness of the plasma filter. In this case, it is desirable to separately provide the metal material for these film thicknesses, or to form the metal film thickness separately.

[0684] Meanwhile, in the plasma filter 116, since the metal film is prone to reflecting light and has a low aperture ratio, so-called glare or ghosting may occur, in which the reflected light is reflected by components such as sealing glass or IR cut-off filters and re-enters the sensor.

[0685] As a countermeasure, in the combination of wavelengths close to each other in the transmission spectrum, the color filter can be positioned on the upper side, and the plasma filter 116 can be positioned on the lower side. With this configuration, wavelength components that are easily reflected by the plasma filter 116 upon incident light are absorbed by the color filter, and components reflected by the plasma filter 116 are also absorbed again by the color filter, thereby suppressing glare and ghosting.

[0686] Note that the plasma filter 116 has low transmittance in principle. To obtain sufficient signal strength for authentication, it is desirable to set a variable storage time for each sub-pixel. Specifically, the imaging element 10 can be configured such that the storage time of sub-pixels including the plasma filter 116 is extended, while the storage time of sub-pixels not including the plasma filter 116 is shortened.

[0687] Next, a cross-sectional view will be used to illustrate the arrangement of various filters in pixel 102 and sub-pixel 106. The following figures show the structure of pixel 102, etc., on the substrate, but wiring layer 302, etc., is not shown. Other necessary structures are not shown appropriately; only the relationship between pixel 102, etc., and filter 112, etc., is highlighted. Therefore, it is assumed that further components (not shown appropriately) are provided.

[0688] (Embodiment 22)

[0689] Figure 34 This is a schematic cross-sectional view of pixel 102, showing an example arrangement of filter 112. Although filter 112 is, for example, an insulator, the shading lines are omitted. Figure 34 As shown, pixel 102 may include a filter 112 located between interlayer film 306 and on-chip lens. An adhesive layer 308 may also be provided between interlayer film 306 and filter 112.

[0690] The advantage of the structure of pixel 102 according to this embodiment is that the thermal constraint during the wall structure processing is not affected during its formation, while ordinary organic filters require high-temperature treatment (e.g., denaturation) which can cause problems such as reduced sensitivity at 300 degrees or higher.

[0691] (23rd Embodiment)

[0692] Figure 35 This is a schematic cross-sectional view of pixel 102, showing an example of the arrangement of filter 112. (See attached image.) Figure 35 As shown, pixel 102 may include a planarization film 318 disposed on a metal film 316 of the photoelectric conversion element isolation section 110 and a filter 112 disposed thereafter. The planarization film 318 is, for example, a layer comprising a substance such as a transparent organic material and having a planarized upper surface, the transparent organic material having a viscosity adjusted similarly to that of the adhesive layer 308.

[0693] As a variation, although not shown, the filter 112 can be directly disposed above the metal film 316.

[0694] In filter 112, if the filter is exposed during the trenching process of the light-shielding wall 108, deposits will adhere to the cavity wall of the device. Therefore, considering process differences such as linewidth and misalignment, it is desirable to position the filter end so that the filter is not exposed. When a gap is formed between filter 112 and the metal film 316 of the photoelectric conversion element isolation portion 110 when viewed from the top surface, color mixing deteriorates. Therefore, for example, considering process differences such as linewidth and misalignment, it is desirable for the metal film 316 and filter 112 to overlap without gaps.

[0695] (Embodiment 24)

[0696] Figure 36 This is a schematic cross-sectional view of pixel 102, illustrating an example arrangement of filter 114. (See attached image.) Figure 36 As shown, the filter 114 is disposed in the interlayer film 306 such that it covers the upper surface of each sub-pixel 106. For example, each filter 114 is arranged to cover the sub-pixel 106 from above the photoelectric conversion element isolation portion 110.

[0697] Similarly, in this case, similar to the case described above where a filter 112 is provided on the photoelectric conversion element isolation section 110, a planarization film 318 can be provided, and a filter 114 can be provided on the planarization film.

[0698] Filter 114 may not be the same filter across the entire span of pixel 102, as described above. For example, in Figure 36 In the middle, the left filter 114 can be a green filter 114G, while the right filter 114 can be a red filter 114R.

[0699] Furthermore, for example, the sub-pixel 106 located at the center can output a signal of interest sensitivity without the application of a filter. In this case, the signal of interest sensitivity can be acquired, and color information can be interpolated in the peripheral sub-pixels 106 to which the filter 114 is applied.

[0700] (Embodiment 25)

[0701] Figure 37 This is a schematic cross-sectional view of pixel 102, showing an example arrangement of filters 112 and 114. (See attached image.) Figure 37 As shown, two layers of filters 112 and 114 can be set in the vertical direction.

[0702] For example, the left pixel 102 may include an on-chip filter 112IRC that absorbs infrared light at its upper part and, for example, different filters 114 for each sub-pixel 106 at its lower part, such as any filter 114 like a green filter 114G, a red filter 114R, and a blue filter 114B. Meanwhile, the right pixel 102 may include, for example, a filter 112IR that transmits only infrared light at its upper part.

[0703] With this configuration, color information and infrared information, which also provide angular information, can be acquired simultaneously without installing an infrared absorption filter on a part other than the imaging element 10 of the electronic device 1. Furthermore, a solid-state imaging element with a new transmission spectrum can be achieved by combining different filters vertically.

[0704] (Embodiment 26)

[0705] Here, we will explain the case of overlapping color filters in terms of the spectrum.

[0706] Figure 38 This is a graph illustrating an example of the characteristics of a color filter. In the following spectral description, the horizontal axis represents wavelength [nm], and the vertical axis represents light receiving sensitivity (quantum efficiency (QE)) [%).

[0707] Solid lines represent the sensitivity characteristics of the red filter, dotted lines represent the sensitivity characteristics of the green filter, and alternating long and short dashed lines represent the sensitivity characteristics of the blue filter. As described above, the filters of each color are designed to increase the light receiving sensitivity (transmittance) within a predetermined wavelength range.

[0708] Filters used in various imaging devices and the like include materials with various transmission spectra obtained by preparing pigments and dyes. For example, to emphasize the light-receiving sensitivity of a filter, there are combinations that broaden the half-width and overlap the spectra of different colors. When two filters with overlapping spectra are stacked one on top of the other, their respective transmission spectra are superimposed, and a new narrowband sensitivity spectrum can be achieved.

[0709] Figure 39 An example of transmittance is shown when green and red filters are stacked one on top of the other. Figure 39 As shown, by using stacked green and red filters, a characteristic sensitivity spectrum with high sensitivity in the wavelength region of 550 to 600 nm was obtained.

[0710] For example, such as Figure 271 As shown, regardless of skin color, the wavelength region with large spectral variations exists around 550 to 600 nm, and more typically around 590 nm. For this reason, biometric authentication is usually performed in areas such as... Figure 39 Perform within the wavelength range shown.

[0711] Based on the above facts, for example, Figure 39 The filter shown, constructed by stacking green and red filters, can be considered a filter combination with sensitivity spectral characteristics suitable for biometric authentication. For example, this characteristic remains unchanged even when there is a gap between the green and red filters, in the presence of a substance that transmits all visible light. Therefore, filters of different colors can be provided in both filter 112 and filter 114 shown in the above figures.

[0712] For example, as in Figure 37When the filters are stacked in the right pixel 102, a filter combination suitable for biometric authentication can be obtained by setting a red filter 112R directly below the lens 104 and setting a green filter 114G on the sub-pixel 106.

[0713] As another example, Figure 40 An example of transmittance is shown when green and blue filters are stacked one on top of the other. Meanwhile, in color matching experiments in color engineering, a negative region that cannot be reproduced by additive color mixing of red, blue, and green primary colors exists approximately between 436 and 546 nm, and four-primary-color encoding of red, blue, green, and emerald has been proposed as a means to compensate for the image quality impact in this region. Figure 40 The transmission spectrum can be used for emerald pixels in four-color coding.

[0714] Figure 41 An example of the sensitivity spectrum behavior when the film thickness of a green filter is varied is shown. The figure illustrates an example where the solid line represents a green filter film thickness of 500 nm, the broken line represents 400 nm, and the dotted line represents 300 nm. The film thickness dependence of the green filter follows the Lambert-Beer law. That is, the effect of the filter film thickness decreases as the absorptivity (absorbance) decreases (transmittance increases) and increases as the absorptivity (absorbance) increases (transmittance decreases). This can be seen from... Figure 41 The relationship between solid lines, broken lines, and dotted lines in the graph is used to confirm the dependence caused by film thickness.

[0715] Figure 42 This is a graph showing the spectral sensitivity with respect to wavelength when green and red filters with different film thicknesses are stacked. Similar to... Figure 41 An example of the following is shown: a solid line indicates that the thickness of the green filter is 500 nm, a broken line indicates 400 nm, and a dotted line indicates 300 nm.

[0716] like Figure 42 As shown, relative to Figure 39 The curve can be used to alter the state of the side lobes of the sensitivity spectrum at higher wavelengths (e.g., above 580 nm). Using this result, the thickness of the filter can be changed by matching the sensitivity spectrum to the spectrum of a hypothetical subject.

[0717] In addition, Figure 37 For example, a red filter 112R can be disposed in the upper part of the left pixel 102, and green filters 114G with different film thicknesses can be disposed for each sub-pixel 106 in the lower part. Figure 41 and 42As shown, the green filter has, for example, a thickness of 300 nm and a thickness of 500 nm.

[0718] By using green filters 114G with different film thicknesses, two spectra with different sidelobe sensitivities in the wavelength region above 580 nm can be obtained. Based on the differences between these sensitivity spectra, the subject spectrum above 580 nm can be extracted.

[0719] To obtain the difference between the signals received by sub-pixels 106 corresponding to color filters 114G with different film thicknesses, image shifting processing can be performed taking into account the parallax of each sub-pixel 106 and the subject distance. Alternatively, even with color filters of the same color, a similar effect can be obtained by changing the type of pigment or the mixing ratio of the pigments.

[0720] Figure 43 This is a graph showing the sensitivity spectra of the red and blue filters separately. The solid line represents the sensitivity of the red filter, and the alternating long and short lines represent the sensitivity of the blue filter. As mentioned above, the regions between the red and blue filters where the sensitivity in the visible light region (approximately 400 to 700 nm) becomes sufficiently high (e.g., above 10%) do not overlap.

[0721] Figure 44 Another example of the sensitivity spectrum obtained when different color filters are arranged vertically based on the above description is shown.

[0722] Because the red and blue filters have separate transmission spectral peaks in the visible light region, they act complementaryly when stacked. Therefore, by stacking the red and blue filters, light is essentially blocked throughout the entire visible light region.

[0723] Meanwhile, in the near-infrared region, both exhibit almost identical transmission spectral peaks between 800 nm and 900 nm. Therefore, when these color filters are stacked, they become sensitive to near-infrared radiation. In other words, by using these color filters in a stacked manner, they can be used as near-infrared filters.

[0724] Note that in the appendix Figure 38 , 39 Among 40, 41, 42, 43 and 44, the following have already been used. Figure 37 The structure is illustrated as an example, but the construction of stacked color filters is not limited to this. In this embodiment, where the filters are stacked vertically, for example, it is possible to... Figure 34 , 35 and 36, and will be explained later. Figure 47 A second stage is formed on the single-layer filter.

[0725] More specifically, color filters can be stacked as filters 112 and 114, or, as another example, color filters can be stacked as two layers of filters 112 or two layers of filters 114. Furthermore, the combination of color filters is not limited to the combinations described above, and can also be combinations other than these. Additionally, the types of stacked color filters are not limited to two; three or more types of filters can be stacked in a third direction.

[0726] (Embodiment 27)

[0727] In the above embodiments, the stacking of color filters has been described, but it will be shown that one of the color filters is in the form of a plasma filter.

[0728] Figure 45 This is a cross-sectional view showing an example of the structure of an imaging pixel according to this embodiment. The imaging element 10 includes a lens 104, a red filter 112R, an adhesive layer 308, a light-shielding wall 108, an interlayer film 306, and a plasma filter 116.

[0729] Lens 104 is equivalent to the lens described in the foregoing embodiments.

[0730] The filter 112R is positioned below the lens 104.

[0731] An adhesive layer 308 is provided below the filter 112R to ensure close contact between the filter 112R and the interlayer film 306. Depending on the structure of the interlayer film 306 and the filter 112R, the adhesive layer 308 is not necessary.

[0732] Interlayer membrane 306 is disposed below filter 112R via adhesive layer 308. As described above, interlayer membrane contains, for example, a permeable material.

[0733] Crosstalk between the interlayer films 306 of the pixel 102 is suppressed by the light-shielding wall 108.

[0734] Then, in the above embodiments, various filters 114 are set at their respective positions. Figure 31 The plasma filter 116 is shown. The plasma filter 116 is constructed by forming a hole 116B in a metal film (e.g., an aluminum film) 116A. For example, an interlayer film 306 is filled inside the hole 116B.

[0735] For example, Figure 32 and 33 The sensitivity of the plasma filter 116 to wavelengths is shown. Specific examples of the spectral configurations shown in these figures are suitable for detecting wavelengths such as… Figure 271The spectrum shown is unique to human skin. Therefore, the spectrum obtained through the plasma filter 116 is suitable for biometric authentication.

[0736] Figure 46 From Figure 45 A planar view of the plasma filter 116 viewed above the imaging pixels. (See image.) Figure 46 As shown, the imaging element 10 includes a plasma filter 116 with apertures 116B that have different shapes and spacings for each sub-pixel 106.

[0737] For example, plasma filter 116a is designed with an aperture spacing of 320 nm and readily transmits light with a wavelength of 550 nm, and plasma filter 116b is designed with an aperture spacing of 340 nm and readily transmits light with a wavelength of 580 nm. Similarly, plasma filters can be formed with different aperture spacings such that plasma filter 116c readily transmits light with a wavelength of 610 nm, plasma filter 116d readily transmits light with a wavelength of 640 nm, plasma filter 116e readily transmits light with a wavelength of 670 nm, plasma filter 116f readily transmits light with a wavelength of 700 nm, plasma filter 116g readily transmits light with a wavelength of 730 nm, plasma filter 116h readily transmits light with a wavelength of 760 nm, and plasma filter 116i readily transmits light with a wavelength of 790 nm.

[0738] By designing the plasma filter 116 for each sub-pixel 106 in this manner, the imaging element 10 can obtain a spectrum in the wavelength range of 550 to 790 nm.

[0739] For example, by setting on these plasma filters Figure 41 The red filter 112R shown in the curve is able to suppress... Figure 33 The effects of waveguide modes below the cutoff wavelength are shown. Furthermore, it can suppress flares and ghosting.

[0740] Figure 47 This is a plan view showing an example of the structure of an imaging element. (e.g.) Figure 47 As shown, for example, the same red filter 112R is set for multiple pixels 102.

[0741] Figure 48 It is shown Figure 47 The diagram shows a plan view illustrating an example structure of sub-pixel 106 in an imaging plane. Within an imaging element 10, sub-pixels 106 contain plasma filters 116 of the same shape. Different imaging elements 10 may contain different plasma filters 116.

[0742] By setting the filter 112R and the plasma filter 116 in this way, an image signal that is easy to apply demosaicing to each sub-pixel image can be obtained.

[0743] (Embodiment 28)

[0744] Figure 49 This is a cross-sectional view showing an example of the structure of an imaging pixel. Regarding the above... Figure 36 The optical path of pixel 102 is designed so that the uppermost part of the metal film 316 does not become the focus.

[0745] The difference in this structure is that the beam diameter near the uppermost part of the metal film 316 is larger than at least one sub-pixel 106. Even when this structure is combined with a telecentric optical system that is incident substantially perpendicularly on the imaging device, light information can be obtained through multiple sub-pixels 106 in pixel 102.

[0746] As mentioned above, various color filters can be arranged appropriately according to their intended use. For example, such as Figure 21 , 22 As shown in figures 23, 24, 25, 26, and 27, different colored filters can be used for each pixel 102. As another example, see the figure... Figure 28A , 28B As shown in 29 and 30, filters of different colors can be appropriately arranged in a pixel 102.

[0747] Furthermore, color filters can be applied to all pixels 102 included in the imaging element 10, or color filters can be applied to some pixels 102. Additionally, filters can be stacked in the vertical direction to have sensitivity spectra that differ from the characteristics of each individual color filter.

[0748] Note that sub-pixels 106 can be configured to include an organic photoelectric conversion film instead of a color filter, or a plasma filter can be used. As mentioned above, alternatives to color filters can be used, as long as information can be appropriately acquired for each color (i.e., for each light wavelength).

[0749] The construction of these filters can be appropriately selected based on their intended use, design constraints, etc. Specific examples have been described in the foregoing embodiments.

[0750] For example, filters 112, 114, or plasma filters 116 use materials such as pigments or dyes to transmit light of a desired wavelength and obtain spectral information of the light from the subject. Filter 112 can be disposed on, for example, an interlayer film 306, and an adhesive layer 308 that also serves as a planarization film can be disposed between the interlayer film 306 and the filter 112.

[0751] For example, a filter 114 or a plasma filter 116 can be disposed on the metal film 316, and an adhesive layer that also serves as a planarization film can be disposed between the metal film 316 and the filter 114 or the plasma filter 116.

[0752] For example, a filter 114 or a plasma filter 116 can be provided for each sub-pixel 106, or the filter 114 or the plasma filter 116 can be different for each sub-pixel 106. Furthermore, a filter 114 or a plasma filter 116 with the same structure can be provided for each pixel 102, and these filters can be different for each pixel 102. A color filter may not be provided to emphasize sensitivity and resolution.

[0753] (Embodiment 29)

[0754] The various aspects of the present invention are not limited to the rear surface irradiation type in each of the above embodiments.

[0755] Figure 50 This is a cross-sectional view showing pixel 102 in a front-surface illumination type imaging element. The difference between a front-surface illumination type sensor and a rear-surface illumination type sensor is that the wiring layer and pixel transistors are formed on the illumination surface side. This structural difference will be explained.

[0756] In the front surface illumination type, although there are some crosstalk paths in the gaps between wirings and between through interconnects, the metal film (wiring 304) of wiring layer 302 is used as a light shield 108 in the front surface illumination type.

[0757] In the front surface illumination type, the optical path opening below the lens 104 is narrowed due to the wiring layer 302. Therefore, compared with the rear surface illumination type having the same pixel size and the same lens structure, the oblique incidence characteristics of the pixel 102 are degraded in the front surface illumination type due to the vignetting of the wiring 304.

[0758] Furthermore, the wiring layer 302 has the specifications required for circuitry. Therefore, even when a reduced height is desired as part of the optical path design, it cannot be designed with the same freedom as the rear surface illumination type.

[0759] In the front-surface illumination type, the pixel transistor is formed on the illumination surface side of the semiconductor substrate 300 and is confined within the potential design region of the pixel. Note that, although not shown, it is similar to... Figure 7 In this process, an insulating film 314 is disposed on the surface of the semiconductor substrate 300.

[0760] In the front-surface illumination type, the area and volume of the wiring layer 302 increase when attempting to accelerate operation through parallel processing. For this reason, acceleration, sensitivity, and oblique incidence characteristics are subject to a trade-off. Meanwhile, in the rear-surface illumination type, the wiring layer 302 allows for greater freedom in wiring design since its placement does not affect the optical path design.

[0761] In the front surface irradiation type, since the organic film color filter (filter 114) cannot withstand the heat generated during the formation process of the wiring layer 302, the arrangement of the color filter is limited to the filter 112 on the wiring layer 302. Meanwhile, since the plasma filter 116 is a metal film, the plasma filter can be formed at any height of the wiring layer 302, but this will affect the wiring capacitance.

[0762] In these comparisons, the rear-surface illumination type has advantages in terms of product specifications and characteristics, while the front-surface illumination type has the advantages of not requiring a support substrate, having fewer process steps, and lower manufacturing costs. Depending on the required accuracy of light reception for the pixels 102 in the imaging element 10, the front-surface illumination type is usually sufficient. In this case, the front-surface illumination type imaging element 10 can be used.

[0763] In the following embodiments, the rear surface irradiation type is mainly used as an example, but this embodiment is not limited to the rear surface irradiation type; for example, the front surface irradiation type can also be used. In addition, the stacking of filters in the above embodiments can also be implemented similarly within the scope of the above-described limitations.

[0764] (Embodiment 30)

[0765] In the above description, pixel 102, sub-pixel 106, filters 112 and 114, etc., have been described. Next, the lens included in pixel 102 will be described. In each of the above embodiments, the case of including an on-chip lens that has undergone an etch-back process during the manufacturing process has been described.

[0766] As lens 104, various lenses can be used besides those that have undergone etch-back treatment. Since each lens has different characteristics, by changing the lens, more appropriate control over light collection, scattering, etc., can be achieved according to the subject to be imaged and the intended use. The various lens configurations in the following embodiments do not necessarily have to be the same on the pixel array. That is, the type of lens used for each pixel 102 can be changed as needed.

[0767] By combining and mixing various lenses for each pixel 102, pixels 102 with various characteristics can be formed in the same pixel array. For example, the lens to be used can be changed based on the position of the pixel 102 in the pixel array.

[0768] In this embodiment, as a variation of the on-chip lens, the case of providing a so-called recirculation lens will be described. More specifically, the form of the light-shielding structure suitable for controlling the variation of the recirculation lens when the recirculation lens is set as lens 104 will be described.

[0769] The method of transferring the lens-shaped resist described in the above embodiments onto the lens material through a back-etching process has the advantage of reducing the gap between lenses by deposition during etching. That is, sensitivity can be improved by reducing the ineffective area of ​​the lens.

[0770] Meanwhile, according to the Fraunhofer diffraction theory, when collecting light with wavelength λ, the spot radius ω0 can be approximated as follows, where the refractive index n of the medium, the focal length f, and the lens size D are defined.

[0771] [Mathematical Expression 3]

[0772]

[0773] That is, as the lens thickness increases and the focal length decreases, or as the lens size increases, the light beam can be narrowed. However, when attempting to increase the lens thickness and simultaneously increase the lens size in a similar manner, there are problems such as increased etching of the lens material, increased deposition in the chamber, and increased maintenance frequency. For device operation, it is assumed that the lens thickness is limited to, for example, about 3 to 4 μm.

[0774] One solution is to form a recirculation lens by heating. Materials used for recirculation lenses, such as those obtained by dissolving a resin, such as acrylic resin, in a solvent and adding a photosensitizer (e.g., ortho-naphthoquinone diazide compound), are already commercially available.

[0775] In reflow lenses, it is difficult to reduce the gap compared to using etching back, and the gap widens, for example, at the diagonal vertices. However, this method offers advantages such as easy formation of thick lenses, fewer processing steps without the need for etching back, and the ability to remove the PAD portion through exposure and development.

[0776] Figure 51 A cross-sectional view of the imaging pixels according to an embodiment is shown. Figure 51The lens 104 shown is a reflow lens disposed in the adhesive layer 308, which serves as a substantially flat substrate. Lens 104 is disposed on the interlayer film 306 through the adhesive layer 308. Note that in the case of a reflow lens, as shown, the boundaries between lenses may not be very clear, but similarly, this will not cause significant differences in the following description.

[0777] Figure 52 A cross-sectional view of the imaging pixels according to an embodiment is shown. Figure 52 The structure is in Figure 51 The structure includes a filter 112. In this way, the filter 112 can be configured based on the above-described embodiment of pixel 102. When the filter 112 is configured, as shown in the figure, the filter 112 can be disposed between the adhesive layer 308 and the lens 104, which serves as a recirculation lens. As another example, the filter 112 can be disposed between the adhesive layer 308 and the interlayer film 306.

[0778] As shown in the figure Figure 51 and 52 As shown, similar to a back-etching lens, a backflow lens can be set as lens 104.

[0779] Figure 53 This is a plan view illustrating an example of a microlens array for a back-etching lens. Conversely, Figure 54 This is a plan view illustrating an example of a microlens array for a recirculation lens. Figure 53 In this configuration, the lens array is formed such that there are almost no gaps between the lenses. Conversely, in... Figure 54 In this case, the gaps between the lenses are relatively wide.

[0780] In the case of forming a microlens array using a reflow lens, shape reproducibility may be poor due to variations in heat treatment. Furthermore, it cannot be said that the material of the reflow lens and silicon oxide have good adhesion. Therefore, as... Figure 51 and 52 As shown, an adhesive layer 308 can be formed between the reflow lens and the interlayer film 306 to ensure close contact between the lens 104 and the interlayer film 306. The adhesive layer 308 may deteriorate due to contact with metal. Therefore, a transparent inorganic film (not shown), such as silicon oxide, can be disposed beneath the adhesive layer 308 to prevent deterioration.

[0781] Figure 55 This is a schematic diagram of an atomic force microscope (AFM) image of a microlens array of a reflow lens. For example, by providing the adhesive layer 308, a microlens array such as... Figure 55 The microlens array shown. To improve the shape reproducibility described above, walls can also be arranged so that the space between lens 104 and adjacent lens 104 is not filled due to heat treatment.

[0782] As described above, according to this embodiment, pixel 102 may include a recirculation lens as lens 104. By using various lenses, characteristics such as sensitivity and angular resolution can be controlled, and suppression of factors such as size increase of imaging element 10 can be achieved. As an example, a recirculation lens can be used. By appropriately designing lens 104 according to its intended use, it can be used for various purposes depending on the application of electronic device 1.

[0783] Furthermore, different lenses may be used on the pixel array of the imaging element 10, and lenses of various methods may be used in combination. For example, the lens to be used may be changed based on the position of the pixel 102 in the pixel array.

[0784] The following sections will further illustrate examples of various lenses. First, the application of the shape of pixel 102 to the recirculation lens will be explained.

[0785] (Embodiment 31)

[0786] Figure 56 A cross-sectional view of an imaging pixel according to an embodiment is shown. Pixel 102 shows an example of an embodiment with respect to lens 104 including a dam (lens isolation portion) having a metal film. The adhesive layer 308 is, for example, an insulator, but the shading lines are omitted. For example, pixel 102 includes a recirculation lens as lens 104. For example, this embodiment is similar to... Figure 51 The difference lies in the fact that the lens material is blocked by a dam during the reflow process. That is, a wall is provided between the lenses 104 of adjacent pixels 102 to avoid contact with adjacent lenses 104.

[0787] The dam stabilizes the shape of the lens 104. Furthermore, by incorporating a metal film within the dam portion, light-shielding properties are improved, and stray light is suppressed. When a metal film is incorporated into the dam, the film-forming process can be generalized by using the same material as the metal embedded in the light-shielding wall 108 as the metal film.

[0788] Figure 57 A cross-sectional view of the imaging pixels according to an embodiment is shown. Essentially, it is similar to... Figure 56 A dam with a metal film is provided between the lenses 104. Figure 57 The imaging pixels include a filter 112. The filter 112 can be disposed between the diaphragms, that is, directly below the lens 104.

[0789] like Figure 56 and 57 As shown, as an example, a dam between the lens 104 is formed by deforming the adhesive layer 308 and the interlayer film 306. A metal film, which serves as a framework, can then be provided, and the metal film can be integrally formed with the light-shielding wall 108.

[0790] Figure 58 , 59 60 is a planar view of the imaging pixels according to an embodiment. For example, Figure 56 and 57 An example of the shape of a dike as viewed from directly above is shown.

[0791] exist Figure 58 In the design, the dam has a rectangular opening. A blocking effect is observed near the side center of the dam. Simultaneously, in the diagonal portions, the lens material does not reach the dam, resulting in stray light from the gaps, and the lens shape may change. However, in terms of sensitivity, this rectangular dam shape is advantageous in terms of area.

[0792] exist Figure 59 In the diagram, viewed from above, a dam is formed at the boundary of pixel 102 to follow the shape of the ineffective area of ​​lens 104. Since the lens material is blocked throughout the dam, the shape of lens 104 is stable. Furthermore, the metallic film on the dam (e.g., a portion of the light-shielding wall 108) also has the advantage of effectively suppressing stray light from the gap portion. As an example, an example has been described where the cross-sectional result obtained by AFM is approximately octagonal, but this embodiment is not limited to this; for example, the dam can be formed into a rectangular shape with rounded corners.

[0793] Figure 60 The feature is that pixel 102 has a near-circular shape, such as a hexagon, and includes a near-circular embankment. The advantage is that all boundaries are rounded and the density of reflow lenses with poor pattern fidelity is increased. For example, in sub-pixels 106 and 102 formed as... Figure 19 In the case of the hexagonal shape shown, a return lens can be effectively formed by forming a dam in this shape.

[0794] Note that, including Figure 58 , 59 The structure of the dam with light-shielding properties shown in Figure 60 is not limited to a backflow lens. For example, this structure can be provided in lens 104 through a back-etching process in the above embodiment. In this case, the light-shielding performance can also be improved.

[0795] Figure 61 A cross-sectional view of an imaging pixel according to an embodiment is shown. Pixel 102, for example, has a dam consisting only of transparent material with respect to the recirculation lens. This structure has better light-blocking properties than... Figure 56 The lens isolation section shown has poor light-blocking properties, but it can suppress sensitivity loss. Due to the embankment shape in the top view plan... Figure 58 , 59 The state of pixel 102 shown in 60 overlaps with that of pixel 102, so its description is omitted.

[0796] Figure 62shows a cross-sectional view of an imaging pixel according to an embodiment. Figure 61 The pixel 102 in includes a filter 112. In Figure 62 the example, similar to Figure 61 the example, a bank made only of a transparent material is provided. Similarly, according to this configuration, the light shielding property is poorer than that of the lens isolation portion having the light shielding wall 108, but sensitivity loss can be suppressed.

[0797] Figure 63 shows a cross-sectional view of an imaging pixel according to an embodiment. The pixel 102 includes a lens isolation portion 120 on the adhesive layer 308. The lens isolation portion 120 has an effect similar to that of the above-described bank in the present embodiment.

[0798] The pixel 102 includes a bank as the lens isolation portion 120, and the bank mainly includes a light-shielding material that is photosensitive to the reflow lens, such as carbon black resist. Compared with the bank including Figure 56 the metal film, the light shielding property is slightly poorer, but the manufacturing process can be reduced. The plan view of the bank shape seen from above coincides with Figure 58 and the like, and thus the description thereof is omitted.

[0799] Figure 64 shows a cross-sectional view of an imaging pixel according to an embodiment. As shown in this figure, the lens isolation portion 120 may be disposed between the filters.

[0800] Figure 65 shows a cross-sectional view of an imaging pixel according to an embodiment. As shown in this figure, the lens isolation portion 120 may be disposed on the filter.

[0801] Similarly to the above, a configuration including the light-shielding lens isolation portion 120 as shown in Figure 63 , 64 and 65 is formed to be used for stabilizing the lens shape in a case where a reflow lens is used as the lens 104 by way of example, but the present invention is not limited thereto. For example, as in the above-described embodiment, in the case of the lens 104 formed by etch-back, the effect of suppressing crosstalk can be exhibited by including the lens isolation portion 120.

[0802] As described above, as in the present embodiment, the lens isolation portion may be formed between the lenses 104 of the adjacent pixels 102. By forming the lens isolation portion, for example, the shape of the reflow lens can be stabilized. Further, as described above, by providing a metal film or the like, or by providing the lens isolation portion including a low transmittance material, the effect of suppressing crosstalk between the pixels 102 can be exhibited. In addition, various forms that exhibit the effect of suppressing sensitivity loss are also as described above.

[0803] (Thirty-second embodiment)

[0804] Figure 66A cross-sectional view of an imaging pixel according to an embodiment is shown. This figure is a view illustrating other structures of the lens included in pixel 102. In this embodiment, similar to the embodiments described above, pixel 102 includes a lens 104 as an on-chip lens, and may further include lenses within pixel 102. That is, an inner lens 118 is disposed between sub-pixel 106 and lens 104.

[0805] By providing the inner lens 118 as in this embodiment, pixel 102 can image light incident via lens 104 onto sub-pixel 106 at close range. By reducing the focal length of the lens, the spot radius ω0 of the converging light of pixel 102 can be reduced according to the Fraunhofer diffraction theory (Equation (3)).

[0806] Notice, Figure 66 The diagram illustrates a structure in which light is incident on the photoelectric conversion element of each sub-pixel 106 via two lenses, but this embodiment is not limited to this structure. For example, light can be incident through three or more lenses.

[0807] (Embodiment 33)

[0808] As an example of the inner lens 118 in the above embodiments, some forms will be described.

[0809] Figure 67 This is a cross-sectional view illustrating an example in which the imaging element 10 according to an embodiment includes an inner lens. In the case where the imaging element 10 includes an inner lens, the oblique incidence characteristics of the light beam in the imaging element 10 can be controlled by changing the distance from the inner lens to the light receiving element.

[0810] In the following text, the arrangement of filters 112, 114 and plasma filter 116 described in the above embodiments is omitted, but these filters can be appropriately arranged even when an inner lens is provided.

[0811] As described above, in addition to the configuration of each of the embodiments described above, the imaging element 10 also includes an inner lens 118. The incident characteristics of light incident through the lens 104 relative to the sub-pixel 106 change depending on the position of the inner lens 118. For example, the characteristics of obliquely incident light change.

[0812] exist Figure 67 In, for example, as in Figure 6 In this configuration, the inner lens 118 is arranged such that light incident perpendicularly to pixel 102 from a third direction is incident on the entire surface of sub-pixel 106 located at the center of pixel 102. In this case, the distance between the inner lens 118 and the photoelectric conversion element isolation section 110 is set to l1.

[0813] Note that until Figure 75In the description, the distance between the inner lens 118 and the photoelectric conversion element isolation portion 110 (the film thickness of the interlayer film 306) was changed, but this embodiment is not limited to this. For example, the distance between the adhesive layer 308 and the inner lens 118 (the film thickness of the interlayer film 306) can be appropriately changed, or the distance between the two can be changed.

[0814] Figure 68 The arrangement of subpixels 106 used in the following description is shown. Subpixels 106 located at the center of pixel 102 in the first direction will be described as subpixels 106C, 106D, 106E, 106F and 106G along the second direction.

[0815] Figure 69 It is shown in such Figure 67 The graph shows the light-receiving characteristics of sub-pixel 106 when the inner lens 118 is provided. As a non-limiting example, pixel 102 has a size of 6 μm and includes 5 × 5 = 25 sub-pixels 106 of 1.2 μm each.

[0816] like Figure 67 As shown, the imaging element 10 includes an inner lens 118 in the pixel 102, and a metal film 316 is embedded in the photoelectric conversion element isolation portion 110. Figure 68 In the diagram, the solid line represents the sensitivity of sub-pixel 106E, the dotted line represents the sensitivity of sub-pixel 106D, the broken line represents the sensitivity of sub-pixel 106F, the alternating long and short lines represent the sensitivity of sub-pixel 106C, and one long and two short lines represent the sensitivity of sub-pixel 106G.

[0817] The vertical axis of the graph, without subpixel division, defines the angle of incidence of pixel 102 in the second direction with 0-degree sensitivity as a normalization factor. The effect of the reduction in the number of photons per unit area of ​​incident light due to cosθ is returned and corrected.

[0818] like Figure 69 As shown, the sensitivity of sub-pixel 106G located at the center decreases towards the outside of pixel 102.

[0819] (34th embodiment)

[0820] Figure 70 This is a cross-sectional view illustrating an example of an imaging element 10 according to an embodiment, including an inner lens 118. In this embodiment, the optical path is designed such that the uppermost part of the metal film 316 becomes the focal point in the sub-pixel 106E located at the center of pixel 102. For example, by... Figure 67 The l1 in the image is changed to l2 to achieve the optical path.

[0821] Figure 71 It is shown Figure 70The sensitivity curve is shown in the figure. Although the difference between the 106 sub-pixels increases, it has the advantage of being able to obtain a high-resolution image at the center.

[0822] (Embodiment 35)

[0823] Figure 72 This is a view showing the inner lens 118 and the photoelectric conversion element isolation section 110 separated by a distance l3, which is between the distance l4 at the end of the pixel 102 and... Figure 70 The distance between them is l2.

[0824] Figure 73 It is shown Figure 72 The graph shows the sensitivity curves of each sub-pixel under the following conditions. In this case, it has the advantages of being able to uniformize the sensitivity and angular resolution among sub-pixels, reducing the characteristic differences between sub-pixels, and making the processing of the imaging element easier in image processing such as PSF correction and image synthesis, which will be described later.

[0825] (Embodiment 36)

[0826] Figure 74 This is a cross-sectional view with a distance l4 between the inner lens 118 and the photoelectric conversion element isolation section 110, that is, the upper part of the photoelectric conversion element isolation section 110 of the sub-pixel 106 located at the end becomes the focal point. As shown in this figure, taking into account the geometric extension of the optical path length at the end of the pixel 102, the optical path can be designed such that the end of the pixel 102 becomes the focal point.

[0827] Figure 75 It is shown Figure 74 The graph shows the sensitivity curves of each sub-pixel under this condition. In this case, since the light receiving sensitivity of the sub-pixels 106C and 106G at the end can be maximized, for example, when acquiring parallax images, the features at the end can be extracted.

[0828] Imaging element 10 may include an inner lens 118 at a distance different from those described in embodiments 30 to 33.

[0829] For example, the optical path can be designed such that the focal position of pixel 102 is significantly offset relative to the height of the metal film 316, and the beam diameter becomes larger than that of at least the sub-pixel 106 near the uppermost part of the metal film 316. With this design, for example, even when combined with a telecentric optical system that is perpendicular to the imaging device, it has the advantage that not only the central sub-pixel 106 but also the peripheral sub-pixels 106 can acquire the light information in pixel 102.

[0830] As described above, the focal position of lens 104 is determined relative to assumed optical characteristics (wavelength and angle) based on the layer thickness of the light-gathering structure, the lens thickness, and the optical physical properties of each material. The oblique incidence characteristics can be controlled using any of these parameters, and the optical path design is not limited to the height of the lower wall (l1 to l4 mentioned above).

[0831] (Embodiment 37)

[0832] Figure 76 This is a cross-sectional view showing the imaging pixels according to an embodiment. Figure 76 This is a view showing another configuration of the lens 104 included in pixel 102. Pixel 102 includes a Fresnel lens 122 as an on-chip lens. The Fresnel lens 122 has a shape that concentrically divides the refractive lens to reduce its thickness.

[0833] By configuring Fresnel lens 122 as lens 104 in this embodiment, for example, when lens forming is performed using nanoimprint as described later, it has the advantage that the shape difference caused by UV irradiation or heat increases with the increase of the volume of the lens material.

[0834] (Embodiment 38)

[0835] Figure 77 This is a plan view illustrating an example of a lens included in an imaging pixel according to an embodiment. Pixel 102 includes a diffractive lens 124 as a lens. The diffractive lens 124 is a lens capable of converging light by designing the depth of the grooves according to the wavelength and the spacing of the grooves according to the diffraction angle, and utilizing the diffraction phenomenon of a micro-undulation structure equal to or less than the wavelength.

[0836] Figure 78 This is a cross-sectional view illustrating an example of a lens included in an imaging pixel according to an embodiment. That is, Figure 78 It is along Figure 77 A cross-sectional view of the BB line.

[0837] exist Figure 77 and 78 In the diagram, the white areas between the diagonal regions contain materials with different transmittances (different refractive indices). By changing the transmittance in this way, and based on the groove depth and the spacing between the grooves as defined above, light is focused through diffraction.

[0838] Pixel 102 may include a diffractive lens 124 as a lens. Note that a Fresnel lens is based on pure refraction in a processing height difference that is sufficiently large than the wavelength, and diffractive lenses and Fresnel lenses are completely different in principle.

[0839] Figure 79This is a cross-sectional view illustrating an example of an imaging pixel according to an embodiment. For example, as described above, pixel 102 may include a diffraction lens 124 as an on-chip lens (lens 104). For example, as... Figure 79 As shown, the diffraction lens 124 may include a plurality of fine undulations, for example, concentrically arranged around the optical axis, on the surface of a resin, inorganic film, or the like, having a depth approximately equal to the wavelength of light. Such a diffraction lens is called a zone plate type (Fresnel zone plate). The shape of the diffraction lens 124 is not limited to a concentric circle shape; for example, it may be octagonal, hexagonal, rectangular, etc.

[0840] As mentioned above, a diffractive lens can be used as lens 104, but is not limited to this. Several methods of using a diffractive lens will be described. For example, as... Figure 79 As shown, only one diffraction lens 124 can be set for each pixel 102.

[0841] Figure 80 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 80 As shown, a diffraction lens 126 can be used instead of the inner lens 118. The diffraction lens 126 does not have a table, but may suitably include a table with transparency or high transmittance.

[0842] Figure 81 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 81 As shown, a two-stage structure can be adopted, consisting of a diffractive lens 124 as an on-plate lens and an inner lens 118.

[0843] Note that in Figure 80 and 81 In this case, the lens is constructed as a two-stage lens, but a multi-stage lens construction comprising more than two lenses can also be used. When multiple lenses are stacked along a third direction, any number of the lenses can be used as diffractive lenses.

[0844] When the wavelength is λ, the diffraction order is m, the diffraction grating spacing is d, and the refractive indices of the incident and emitting materials are n1 and n2, respectively, the diffraction grating causes interference in the region where the following relational expression holds.

[0845] [Mathematical Expression 4]

[0846]

[0847] Figure 82 This is a view illustrating a diffraction grating. In Figure 82In the simple slit structure shown, the intensity of the transmitted light is dispersed across multiple diffraction points. The emission direction of the diffracted light is determined based on equation (4) above. For example, the direction of the first-order light diffracts in the direction of θ2 obtained when θ1 = 0 and m = 1 in equation (4), and diffraction fringes are produced. It can be seen from equation (4) that the direction in which the fringes are produced varies with the wavelength.

[0848] Figure 83 This is a view illustrating another example of a diffraction grating. This type of diffraction grating has a sawtooth shape known as blazing. Blazing increases the diffraction efficiency for a specific wavelength. This specific wavelength λ can be expressed using the blaze angle γ by the following formula. Here, n is the relative refractive index.

[0849] [Mathematical Expression 5]

[0850]

[0851] In a blaze, the undulations of the diffraction grating can be replaced with a sawtooth shape, and the angle of the tilted surface can be determined so that the wavefront diffracted to the target diffraction order is parallel everywhere.

[0852] Due to the use of interference effects, diffractive lenses 124 and 126 differ from refractive lenses in their responsiveness to changes in the wavelength of incident light, such as focal length. Pixel 102 can use this difference to correct chromatic aberration by combining a diffractive lens with a refractive lens optical system.

[0853] Conversely, in pixel 102, chromatic aberration can be actively generated using a diffractive lens, and spectral analysis can be performed using the output from each sub-pixel 106 in pixel 102.

[0854] Furthermore, each pixel 102 may include diffractive lenses with different characteristics from each other. For example, while a refractive on-chip lens in an imaging device performs pupil correction through continuous positional shifts, a diffractive lens can freely achieve individual focusing states by including diffractive lenses with different shapes in each pixel 102, regardless of the lens states of adjacent pixels.

[0855] As described above, by using diffractive lenses, pixels 102 with properties different from those of refracting lenses can be formed. These lenses can be used in combination, or lenses can be combined for each pixel to have different properties. By appropriately using diffractive lenses, light with properties different from those in the case of using refracting lenses can be received.

[0856] Notice, Figure 79 , 80Examples shown in Figures 81 and 81 are without filters 112 and lens isolation portions 120, but this embodiment is not limited thereto. As described in the above embodiments, filters 112 and lens isolation portions 120 can be appropriately provided as needed.

[0857] (Example 39)

[0858] By forming the lens 104 and inner lens 118 in various forms as described above, light reception with various characteristics can be achieved. Similarly, the pixel 102 can also undergo pupil correction depending on the arrangement and type of the lens. The plurality of sub-pixels 106 included in the pixel 102 of the above embodiments can simultaneously acquire information with different parallaxes with respect to the lens 104, but by adding pupil correction for offsetting the position of the lens 104, the angular range of receivable light can be shifted.

[0859] For example, by shifting the on-chip lens outward in proportion to the distance from the chip center, the viewing angle of the subpixel image is expanded; conversely, by shifting the on-chip lens towards the chip center, the resolution of the subpixel image can be increased. Furthermore, when the optical system 9 includes lenses, by performing pupil correction for each image height based on the lens's main beam, the subject image can be effectively received across the entire viewing angle.

[0860] Figure 84 This is a cross-sectional view of an imaging pixel according to an embodiment. As a structure according to this embodiment, for example, some pixels 102 in the pixel array 100 have the configuration shown in this cross-sectional view. Pixel 102 includes an inner lens 118, the position of which is offset relative to lens 104 in at least one of a first direction and a second direction. As an example, the inner lens 118 is offset, but pixel 102 may not include the inner lens 118. In this case, a similar effect can be obtained by offsetting the position of a sub-pixel 106 located at the center of pixel 102 from the center.

[0861] For example, pixel 102 located at the end of pixel array 100 has Figure 84 The large offset is shown, while the pixel 102 located at the center of the pixel array 100 has a small offset or no offset.

[0862] Figure 85 It is shown Figure 84 The graph shows the light receiving sensitivity of pixel 102. It can be seen that, compared to... Figure 69 Compared to the light-receiving sensitivity without pupil correction, the light-receiving sensitivity of light incident from a predetermined oblique direction is higher. This graph illustrates the state where pupil correction is applied at the viewing angle end in the second direction, as an example of the arrangement of pixels 102, and shows the oblique incidence characteristics of each pixel. Note that this structure has... Figure 70 A similar structure is used, and the optical path is designed so that the uppermost part of the metal film 316 becomes the focal point. The measurement methods, analysis methods, etc., are also the same as in the above embodiments, so repeated detailed descriptions are omitted.

[0863] For example, the pupil correction amount can be varied according to the distance from the chip center and increases towards the edge. Furthermore, the pupil correction offset can increase with the layer thickness at the surface of the semiconductor substrate 300. For example, in Figure 84 In this case, the pupil correction amount can be increased according to the height of the layer thickness in the order of lens 104 > filter 112 = inner lens 118 = light shield 108A ≥ light shield 108B ≥ (the opening position of the metal film 316 in the photoelectric conversion element isolation part 110).

[0864] Regarding the pupil correction amount, when a gap is created in the light-shielding structure, this gap becomes a path for stray light components to leak out, thus degrading performance. To avoid degradation, it is preferable to construct the light-shielding wall 108A with a portion (contact area) overlapping with the light-shielding wall 108B in the planes of the first and second directions. Similarly, it is desirable to construct the light-shielding wall 108B with a region overlapping with the metal film 316 of the photoelectric conversion element isolation portion 110 in the planes of the first and second directions.

[0865] Furthermore, regarding the pupil correction amount, it is desirable to increase the overlap width between the light-shielding walls 108A and 108B in the design data, i.e., the so-called overlap amount, taking into account the difference in linewidth at the bottom of the light-shielding wall 108A, the difference in linewidth at the top of the light-shielding wall 108B, and the variation in misalignment between the light-shielding walls 108A and 108B.

[0866] from Figure 85 It can be seen that, compared to the case without pupil correction, this design method... Figure 84 The tilted incident characteristics of pixel 102 can maintain a state with almost no fluctuation caused by crosstalk after shifting by about 10 degrees at each peak position.

[0867] Pupil correction can also be achieved using diffractive lenses.

[0868] (Example 40)

[0869] Figure 86This is a schematic view of a diffractive lens 124 for pixels 102 in a pixel array 100 included in an imaging element 10 according to an embodiment. It is assumed that each cell represents a pixel 102. As described above, among the pixels 102 disposed in the array, pixel 102A is the pixel located at the center, and pixels 102B and 102C are pixels located at the center in a first direction in the drawing but offset from the center in a second direction from the center in the circumferential direction. Pixels 102D and 102E are pixels present at positions offset from the center in the circumferential direction in both the first and second directions.

[0870] The figure shows the diffraction lens 124 for each pixel. For example, in the diffraction lens 124A used for pixel 102A located at the center, the center of the grating is as follows: Figure 86 Alignment as shown.

[0871] Meanwhile, the diffraction lens 124B for pixel 102B is formed with multiple gratings, wherein the center of the gratings is offset toward the center of pixel array 100. By setting the gratings in this way, for example, when parallel light passes through the diffraction lens 124B in pixel 102B, an image of light from the subject can be formed at a position in the pixel array 100 offset inward (to the right in the figure) relative to the center of pixel 102B.

[0872] A diffraction lens 124C is disposed in pixel 102C, located at an end relative to pixel 102B, relative to the center of pixel array 100. When parallel light passes through the diffraction lens 124C in pixel 102C, an image of the light from the subject is formed at a position in the pixel array 100 offset inward (to the right in the figure) relative to the center of pixel 102C. Then, due to the difference in grating offset between diffraction lenses 124B and 124C, the light is further offset inward into pixel array 100 and converges in pixel 102C.

[0873] Similarly, this also applies to the case of a center offset from the first direction. Pixel 102D is a pixel arranged at a position offset from the center of pixel array 100 along both the first and second directions (upper left in the figure). Pixel 102D includes, for example, a diffraction lens 124D. The diffraction lens 124D has multiple gratings, wherein the center of the gratings is offset along the central direction of pixel array 100 (lower right in the figure).

[0874] Pixel 102E is a pixel disposed at a position further offset from its end in the same direction as pixel 102D along the first and second directions (upper left in the figure). Pixel 102E includes, for example, a diffraction lens 124E. The diffraction lens 124E includes a plurality of gratings, wherein the center of the gratings is offset along the central direction of the pixel array (lower right in the figure). Then, due to the difference in grating offset between the diffraction lens 124D and the diffraction lens 124E, light is further offset toward the interior of the pixel array 100 and converges in pixel 102E.

[0875] By setting up such a diffraction lens, for example, when parallel light passes through the diffraction lens 124 in pixel 102 in the same way, an image of light from the subject can be formed at a position offset inward (to the right in the figure) from the center of pixel array 100 relative to pixel 102.

[0876] Note that the optical path (i.e., the exit angle) after passing through the diffraction lens 124 can be controlled according to the offset of the grating. Therefore, the design of the diffraction lens can achieve an optical path design equivalent to pupil correction. By using the diffraction lens 124, optimal pupil correction can be performed without moving the center position of the lens 104 of each pixel 102 in the pixel array 100.

[0877] (Example 41)

[0878] An application example of performing pupil correction in pixel 102 in the two embodiments described above will be explained.

[0879] Figure 87 This is a view showing an example of the pixel array 100 of the imaging element 10 according to an embodiment. Figure 87 An example of the application of pupil correction for the diffraction lens 124 is shown.

[0880] Figure 88 It is shown schematically. Figure 87 A view of the diffraction lens 124 of pixel 102 in pixel array 100.

[0881] Figure 89 This is a schematic view illustrating the reading of electronic device 1, which includes components made of... Figure 87 The imaging element 10 is composed of the pixel array 100 shown.

[0882] Electronic device 1 has the function of performing fingerprint authentication and vein authentication on signals received from the same sensor. In this sensor, for example, vein authentication pixels and fingerprint authentication pixels are mixed in a checkered pattern.

[0883] When capturing an image, a finger is placed on the reading surface 12. The fingerprint to be captured is the pattern on the finger's surface, and the veins to be captured are located at a depth of approximately 2 mm from the finger's surface. Because the veins are further away from the imaging element 10 during imaging, a wider field of view of the veins can be captured at a small angle.

[0884] For the sake of simplicity, the following assumptions are made. For example, the distance from the surface of the imaging element to the reading surface 12 is set to 1 mm, the refractive index of a component such as a protective glass between the surface of the imaging element and the reading surface is set to about 1.5, and the refractive index of the inside of the finger is also set to about 1.5.

[0885] In this scenario, when fingerprints and veins are designed to be captured from approximately the same angle, the pupil correction amount for vein authentication is about one-third that for fingerprint pixels. Even when capturing multiple subjects with different optimal angles, the diffraction lens 124 can be designed to perform optimal pupil correction for each subject.

[0886] For example, such as Figure 88 As shown in the upper part, the diffractive lenses included in the pixel 102 for fingerprint authentication are arranged at a large offset at the center and ends, thereby enabling strong pupil correction. In contrast, as shown in the lower part, the diffractive lenses included in the pixel 102 for vein authentication are arranged at a smaller offset at the center and ends than the diffractive lenses for pupil correction used in fingerprint authentication. As shown in the figure, the pupil correction intensity of the diffractive lens 124 used can be varied between fingerprint authentication and vein authentication.

[0887] As described above, pixels 102 with different pupil correction intensities can coexist in the same pixel array 100 through the arrangement of the gratings of the diffraction lens 124. Of course, appropriate filters 112 or 114 or plasma filters 116 are provided in each pixel for verification. With this configuration, the reception of light of the appropriate wavelength, which has undergone appropriate pupil correction according to the application, can be achieved in pixel 102 (sub-pixel 106).

[0888] Note that if an attempt is made to achieve a similar effect in pupil correction using general lens offset, the offset amounts between adjacent lenses will differ, resulting in layout interference. This interference can be avoided by reducing the lens area while maintaining layout freedom, but this is not an ideal implementation due to the poor light-gathering efficiency of small lenses. Therefore, it is preferable to use the diffractive lens described in this embodiment to achieve the pupil correction effect.

[0889] Next, the isolation section 110 of the photoelectric conversion element will be described through some embodiments.

[0890] In this embodiment, various examples of the pixel 102 and the photoelectric conversion element isolation section 110 of each of the above embodiments will be described. Hereinafter, the expressions "at the boundary of pixel 102..." and "in the photoelectric conversion element isolation section 110..." will be used. This expression does not refer to all boundaries, and may be, for example, an element isolation section arranged in a U-shape, an element isolation section divided as shown by dotted lines, etc., and is described as having the effect of "at least a portion of the boundary of pixel 102", "at least a portion of the photoelectric conversion element isolation section 110", etc.

[0891] As described in the above embodiments, in the following figures, as an example, a filter 112 is provided, a filter 114 is not provided, an inner lens 118 is provided, and the lens 104 is a refractive lens, but various combinations of the above-described structures can be used. Furthermore, other structures, such as pupil correction structures, can be appropriately applied.

[0892] (Example 42)

[0893] Figure 90 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. An example of a trench in the photoelectric conversion element isolation portion 110 in the semiconductor substrate 300 is shown. Here, a view showing the shape of a trench that does not penetrate the semiconductor substrate 300 is used, but the trench can penetrate the semiconductor substrate 300 while avoiding interference to the pixel transistor, etc., and this embodiment is not limited to this.

[0894] The photoelectric conversion element isolation portion 110 is formed in a trench of the semiconductor substrate 300, and is formed such that its top overlaps with a portion of the sub-pixel 106.

[0895] Figure 91 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. More precisely, Figure 91 yes Figure 90 The image shows a magnified view of region R, indicated by the dashed line. A similar combination will be used in the following description.

[0896] Photoelectric conversion element isolation section 110 and Figure 6 The difference in the photoelectric conversion element isolation section 110 shown is that an insulating film 314 and a fixed charge film 312 are provided in the trench of the semiconductor substrate 300, and a metal film 316 is provided only above the interface of the semiconductor substrate 300.

[0897] In this structure, charge crosstalk is prevented by a fixed-charge film 312, and optical crosstalk is suppressed by interface reflection caused by the refractive index difference of the trench sidewall portion. Compared with the case where the metal film 316 is embedded in the trench, the effect of suppressing optical crosstalk is weakened, but it has the advantage of suppressing the degradation of dark current and white point characteristics of the metal film 316, and the light absorbed by the metal film 316 contributes to sensitivity.

[0898] (Example 43)

[0899] Figure 92 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation portion 110 is formed in the semiconductor substrate 300 without trenches.

[0900] Figure 93 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. As described above, no trenches are formed in the semiconductor substrate 300, and a metal film 316 is provided above the interface of the semiconductor substrate 300. Although with Figure 6 Compared to other examples, crosstalk suppression is compromised optically and electrically, but requires fewer processes and has an advantage in manufacturing cost.

[0901] (Example 44)

[0902] Figure 94 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different structures for isolating the pixel 102 and for isolating the sub-pixels 106. The photoelectric conversion element isolation section 110 between the sub-pixels 106 in the same pixel 102 is constructed such that no metal film 316 is provided above the interface of the semiconductor substrate 300, but a metal film is provided at the boundary of the pixel 102.

[0903] Figure 95 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. As described above, the metal film 316 is disposed above the interface of the semiconductor substrate 300 at the boundary of the pixel 102, and not disposed at a position outside the boundary of the pixel 102. Figure 92 and 93 Compared to the previous example, although the optical crosstalk suppression effect and angular resolution are compromised, its advantage lies in eliminating vignetting caused by the metal film 316 and improving sensitivity.

[0904] (Example 45)

[0905] Figure 96 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixels 102 and for isolating sub-pixels 106. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a... Figure 94 and 95 The example has a similar structure, and the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 90 and Figure 91 Similar constructions to the example.

[0906] Figure 97 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. Trenches are formed in the semiconductor substrate 300, and an insulating film 314 and a fixed charge film 312 are disposed in the trenches of the photoelectric conversion element isolation section 110 between pixels 102. Although... Figure 94 and 95 The example increases the number of processes, but has the advantage of suppressing optical crosstalk and charge crosstalk between pixels 102.

[0907] In addition, with Figure 90 and 91 In contrast, the optical and charge crosstalk suppression and angular resolution between sub-pixels 106 located outside the boundary of pixel 102 are worse, but the sensitivity is higher. For example, it is suitable for situations where crosstalk suppression is not a major concern, such as when pixel 102 is provided with filter 112 and no filter is provided for each sub-pixel 106.

[0908] (Example 46)

[0909] Figure 98 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixel 102 and isolating sub-pixels 106. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a similar configuration to... Figure 96 and Figure 97 The example has a similar structure, and the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 6 and 7 Similar constructions to the example.

[0910] Figure 99 This is a cross-sectional view showing an example of a photoelectric conversion element isolation section 110 according to an embodiment. Between pixels 102, in addition to an insulating film 314 and a fixed charge film 312, the photoelectric conversion element isolation section 110 also has a metal film 316 embedded in a trench. Figure 96 and 97 Compared to the previous example, the metal film 316 set in the trench near the boundary of pixel 102 causes the dark current and white point characteristics of adjacent sub-pixels 106 to deteriorate, and there is a concern about sensitivity degradation, but it suppresses optical crosstalk between pixels 102.

[0911] (Example 47)

[0912] Figure 100This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixels 102 and for isolating sub-pixels 16. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a configuration in which an insulator is embedded in a trench. The photoelectric conversion element isolation section 110 between pixels 102 has a configuration similar to... Figure 96 and 97 Similar constructions to the example.

[0913] Figure 101 This is a cross-sectional view showing an example of a photoelectric conversion element isolation section 110 according to an embodiment. A metal film 316 is provided above the interface of the semiconductor substrate 300 between pixels 102 in the photoelectric conversion element isolation section 110. Except between pixels 102, the photoelectric conversion element isolation section 110 does not include the metal film 316. Figure 90 and 91 Compared to the previous example, the optical crosstalk suppression effect is compromised, but it has the advantage of improved sensitivity. For example, it is suitable for situations where crosstalk suppression is not a major concern, such as when pixel 102 is provided with filter 112 and no filter is provided for each sub-pixel 106.

[0914] (Example 48)

[0915] Figure 102 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixel 102 and for isolating sub-pixels 16. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a similar configuration to... Figure 100 and 101 The example has a similar structure, but the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 6 and 7 Similar constructions to the example.

[0916] Figure 103 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. Between the pixels 102, in addition to the insulating film 314 and the fixed charge film 312, a metal film 316 is also embedded in the photoelectric conversion element isolation section 110. Figure 100 and 101 Compared to the previous example, there are concerns about dark current, white point characteristic degradation and reduced sensitivity in the sub-pixels 106 between pixels 102, but optical crosstalk between pixels 102 is suppressed.

[0917] (Example 49)

[0918] Figure 104This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixel 102 and for isolating sub-pixels 16. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a similar configuration to... Figure 92 and 93 The example has a similar structure, and the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 96 and 97 Similar constructions to the example.

[0919] Figure 105 This is a cross-sectional view showing an example of a photoelectric conversion element isolation section 110 according to an embodiment. A metal film 316 is disposed above the interface of the semiconductor substrate 300 between pixels 102 in the photoelectric conversion element isolation section 110. Although the sensitivity of the photoelectric conversion element isolation section 110 is reduced due to vignetting caused by the metal film 316, optical crosstalk is suppressed and angular resolution is improved.

[0920] (50th Embodiment)

[0921] Figure 106 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixel 102 and for isolating sub-pixels 16. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a similar configuration to... Figure 92 and Figure 93 The example has a similar structure, and the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 6 and 7 Similar constructions to the example.

[0922] Figure 107 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. Between pixels 102, a metal film 316 is embedded in the photoelectric conversion element isolation section 110, in addition to an insulating film 314 and a fixed charge film 312. Figure 104 and 105 Compared to the previous example, the photoelectric conversion element isolation section 110 has concerns about dark current, white point characteristic degradation and sensitivity reduction in sub-pixels 106 near the boundary of pixel 102, but suppresses optical crosstalk in the boundary portion of pixel 102.

[0923] (51st embodiment)

[0924] Figure 108This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation section 110 is formed by different configurations for isolating pixel 102 and for isolating sub-pixels 16. The photoelectric conversion element isolation section 110 between sub-pixels 106 in the same pixel 102 has a similar configuration to... Figure 90 and 91 The example has a similar structure, and the photoelectric conversion element isolation section 110 between pixels 102 has the same Figure 6 and 7 Similar constructions to the example.

[0925] Figure 109 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. Between pixels 102, a metal film 316 is embedded in the photoelectric conversion element isolation section 110, in addition to an insulating film 314 and a fixed charge film 312. Figure 90 and Figure 91 Compared to the previous example, the photoelectric conversion element isolation section 110 has concerns about dark current, white point characteristic degradation and sensitivity reduction in sub-pixels 106 near the boundary of pixel 102, but suppresses optical crosstalk between pixels 102.

[0926] (52nd Embodiment)

[0927] Figure 110 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Pixel 102 includes a filter 114, and photoelectric conversion element isolation portions 110 between pixels 102 and between sub-pixels 106 within the same pixel 102 can be equivalent to those photoelectric conversion element isolation portions in the above embodiments.

[0928] Figure 110 The example of pixel 102 shown is an example of the arrangement of the photoelectric conversion element isolation section 110 when the sub-pixels 106 included in pixel 102 have filters 114, etc. For example, when sub-pixels 106 including the same filters 114, etc., are adjacent to each other, it is not necessary to divide all sub-pixels 106 equally. For example, as Figure 110 As shown, the photoelectric conversion element isolation section 110 may not be provided between sub-pixels 106. Similarly, pixel 102 may not include the metal film 316, which serves as the photoelectric conversion element isolation section 110, on the interface of the semiconductor substrate 300.

[0929] This is given as an example, and multiple sub-pixels 106 in the above embodiments can be combined into one sub-pixel 106. With this construction, the vignetting effect on the upper part of the photoelectric conversion element isolation section 110 can be suppressed.

[0930] The light-receiving characteristics of each sub-pixel 106, based on the shape and structure of the photoelectric conversion element isolation section 110 in pixel 102, will be described below. A graph illustrates... Figure 68 The sensitivity of the sub-pixel 106 shown. The following characteristics are the oblique incidence characteristics in some of the above embodiments when the photoelectric conversion element isolation section 110 is used.

[0931] The portion above the metal film 316 in the following cases has a similarity to Figure 70 The same structure is used, and the optical path is designed so that the uppermost part of the metal film 316 becomes the focal point. Only the photoelectric conversion element isolation section 110 is different, and the measurement and analysis methods are the same. Figure 69 Since they are the same, their description is omitted here.

[0932] Figure 111 This is a planar cross-sectional view of pixel 102 according to an embodiment. This is using a sensitivity-focused approach. Figure 100 An example of the photoelectric conversion element isolation section 110 of pixel 102. The top view is from... Figure 100 The view observed from the CC section, while the lower view is... Figure 100 The image shows a DD cross-sectional view. Note that, unlike a typical cross-sectional view, the shading does not represent the material, but rather categorizes light and electronic transmittance, for example. For instance, the shaded sections have low light transmittance (close to 0), while other sections have high light transmittance (e.g., transparent).

[0933] In the photoelectric conversion element isolation section 110, an insulating film 314 and a fixed charge film 312 are embedded in the semiconductor substrate 300. The insulating film 314 is, for example, an oxide film, and the surfaces of the semiconductor substrate 300 and the photoelectric conversion element isolation section 110 are formed to be substantially flat.

[0934] Figure 112 It is shown Figure 111 The graph shows the sensitivity characteristics under various conditions. The position of sub-pixel 106 with sensitivity is shown in the graph. Figure 69 The positions are the same as in the figure. In particular, the 3×3 region at the center does not have the metal film 316, and thus obtains good sensitivity characteristics.

[0935] Figure 113 This is a planar cross-sectional view of pixel 102 according to an embodiment. This is achieved using methods that emphasize crosstalk suppression. Figure 6 An example of the photoelectric conversion element isolation section 110 of pixel 102. The top view is... Figure 6 The EE section view in the middle, and the bottom view is Figure 6 FF section view in the image. The shading line and... Figure 111 Similar to the shaded lines in the image.

[0936] An insulating film 314, a fixed charge film 312, and a metal film 316 are embedded in the photoelectric conversion element isolation section 110. The metal film 316 has a shape that protrudes from the surface of the semiconductor substrate 300 and slightly protrudes above the light receiving element of the sub-pixel 106.

[0937] Figure 114 It is shown Figure 113 The graph shows the sensitivity characteristics under various conditions. The position of sub-pixel 106 with sensitivity is shown in the graph. Figure 69 The positions are the same as in the diagram. As shown in the figure, it is the same as... Figure 112 Compared to the previous example, the sensitivity itself is reduced, but crosstalk is significantly improved, and there is less sidelobe overlap between subpixels.

[0938] Figure 115 This is a planar cross-sectional view of pixel 102 according to an embodiment. The metal film 316, except for the metal film at the boundary of pixel 102, is thinned. Figure 111 Similarly, the top view and bottom view show a planar cross-sectional view of the region of the interlayer film 306 of pixel 102 and a cross-sectional view of the semiconductor substrate 300, respectively. This form is... Figure 111 and 113 The shape between them, and the photoelectric conversion element isolation portion 110 protrudes from the surface of the semiconductor substrate 300, but does not cover the upper side of the light receiving element of the sub-pixel 106.

[0939] Figure 116 It is shown Figure 115 The graph shows the sensitivity characteristics under various conditions. The position of sub-pixel 106 with sensitivity is shown in the graph. Figure 69 The positions are the same. As shown in the figure, by making the metal film 316 outside the metal film at the boundary of pixel 102 thinner, both sensitivity and crosstalk can be taken into account.

[0940] According to the various embodiments of the photoelectric conversion element isolation section 110 described above, the photoelectric conversion element isolation section 110 can be designed for various purposes. This design can be determined by various factors such as the arrangement of filters 112 and 114, the required resolution, angular resolution, color resolution, and crosstalk suppression amount. As described above, according to these embodiments, the photoelectric conversion element isolation section 110 can be formed according to various conditions.

[0941] (53rd Embodiment)

[0942] The photoelectric conversion element isolation portion 110 described in the above embodiments is an example in which the semiconductor substrate 300 is formed from the top side in a third-party direction by a manufacturing process. Conversely, the photoelectric conversion element isolation portion 110 can be obtained by forming a trench from the wiring layer 302 side. Some photoelectric conversion element isolation portions 110 formed from the wiring layer 302 side will be described.

[0943] Note that a diagram showing the shape of a trench through the semiconductor substrate 300 is provided, but a trench shape that does not penetrate the semiconductor substrate to the irradiated surface may be used, and the embodiments are not limited.

[0944] Figure 117 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation portion 110 is formed by embedding an insulating film 314 (e.g., silicon nitride or silicon oxynitride, or a multilayer film thereof) into the inner wall of a trench in a semiconductor substrate 300 processed from the wiring layer 302 side.

[0945] According to the photoelectric conversion element isolation section 110 of this embodiment, light crosstalk caused by total internal reflection due to refractive index difference from semiconductor substrate 300 can be suppressed, and charge mixing can be suppressed by insulating film.

[0946] (54th embodiment)

[0947] Figure 118 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. A photoelectric conversion element isolation portion 110 is formed by forming a sidewall film of an insulating film 314 on the inner wall of a trench in a semiconductor substrate 300 processed from the wiring layer 302 side and embedding polysilicon 320 within the sidewall film. As the polysilicon 320, for example, doped polysilicon can be used, or n-type or p-type impurities can be doped after filling the polysilicon.

[0948] According to the photoelectric conversion element isolation section 110 of this embodiment, by applying a negative bias to the polysilicon 320, the pinning effect of the sidewalls can be improved and the dark time characteristics can be improved.

[0949] (55th Embodiment)

[0950] Figure 119 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. The photoelectric conversion element isolation portion 110 is formed by forming an insulating film 314 on the inner wall of a trench in a semiconductor substrate 300 processed from the wiring layer 302 side and embedding a metal film 316 within the sidewall film.

[0951] The metal film 316 can be, for example, a metal film of aluminum, silver, gold, copper, platinum, molybdenum, tungsten, chromium, titanium, nickel, iron, or tellurium, a composite of these metals, or an alloy of these metals. Furthermore, these materials can be formed in multiple layers.

[0952] According to the photoelectric conversion element isolation section 110 of this embodiment, by applying a negative bias to the metal film 316, the pinning effect of the sidewalls can be improved and the dark time characteristics can be enhanced. Furthermore, crosstalk along the path through the photoelectric conversion element isolation section 110 can be suppressed through reflection and absorption of the metal film.

[0953] (56th embodiment)

[0954] Solid-state diffusion is a process that forms a film containing impurities and diffuses these impurities into Si through a heat treatment at, for example, around 1000°C. In typical imaging devices, the PN junction of a photodiode is planarly formed by ion implantation, and the Qs (quantum efficiency) is improved through the PN junction capacitance. Meanwhile, in semiconductors formed using solid-state diffusion-based processes, trenching is performed on the Si substrate. Due to solid-state diffusion, an electric field is added to the trench sidewalls, which have steep profiles, ensuring area in the sidewalls and achieving a significant improvement in Qs.

[0955] Due to thermal limitations, solid-state diffusion is restricted before the formation of wiring layer 302. In solid-state diffusion, since the sidewalls are used as capacitors, a vertical transistor 324 can be employed, which is formed along a third direction of the semiconductor substrate 300 to reach the n-type semiconductor region that performs photoelectric conversion. In this process, the vertical transistor 324 can be connected to a power source, for example, via wiring 304.

[0956] A high-concentration p-type semiconductor region is formed in the semiconductor substrate 300 by solid-state diffusion. During this process, transistors and the like, serving as semiconductor devices, are formed on the wiring layer 302 side of the semiconductor substrate 300, where an n-type semiconductor region exists, and a strong electric field is generated between the p-type and n-type regions. As a countermeasure, a region that is not subject to solid-state diffusion can be formed near the surface of the trench on the wiring layer 302 side, for example, up to approximately 700 nm. This region is formed in the manufactured semiconductor, for example, as shown as well region 310 in the accompanying drawings.

[0957] Some variations of the isolation section 110 of the photoelectric conversion element using solid-phase diffusion will be described.

[0958] Figure 120 This is a cross-sectional view showing an example of the photoelectric conversion element isolation portion 110 according to an embodiment. The semiconductor substrate 300 has a stepped trench shape with different widths along a third direction. The width of the trench on the wiring layer 302 side of the semiconductor substrate 300 is greater than the width on the lens 104 side.

[0959] In the semiconductor substrate 300, a solid-state diffused impurity region 322 is disposed next to a region having a narrow trench width, and an insulating film 314 (e.g., silicon oxide, silicon nitride, etc.) is embedded in the trench. Polysilicon 320 can be embedded as a filler in the gaps of the insulating film 314.

[0960] As polycrystalline silicon, for example, doped polycrystalline silicon can be used, or n-type or p-type impurities can be doped after filling the polycrystalline silicon. By applying a negative bias voltage, the pinning of the trench sidewalls can be enhanced and the dark-time characteristics can be improved.

[0961] (57th embodiment)

[0962] Figure 121 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. Figure 121 and Figure 120 The difference lies in the fact that, without polysilicon 320, only the insulating film 314 is embedded in the trench. Compared to Figure 120 The trench cross-section includes silicon oxide and polycrystalline silicon. According to Fresnel coefficient calculations, this structure can enhance the reflectivity of the sidewall interface.

[0963] (58th embodiment)

[0964] Figure 122 This is a cross-sectional view showing an example of the photoelectric conversion element isolation section 110 according to an embodiment. A metal film 316 is embedded in the trench from the irradiation surface (lens 104) side. An insulating film 314 can be disposed below the metal film 316. Furthermore, a fixed charge film 312 can be disposed below the insulating film 314 (wiring layer 302 side). These films can then be formed from the irradiation surface side. With this configuration, [the following text is incomplete and requires further context: "and..."] Figure 120 Compared to the previous example, this can enhance the optical crosstalk suppression effect.

[0965] Typically, the potential formed by solid-state diffusion from the trench sidewalls accumulates charge in the sidewall portion to increase Qs. Therefore, in a semiconductor substrate 300 of the same thickness, the effect is higher in small pixels and lower in large pixels in terms of area ratio. Furthermore, as the substrate thickness increases, the sidewall area increases, and it is expected that Qs can be improved through solid-state diffusion. In this embodiment, considering the effect of solid-state diffusion and the manufacturing cost associated with it, it is desirable that the aspect ratio, expressed as (thickness of semiconductor substrate 300) ÷ (length of one side of photoelectric conversion element), is at least 4 or more.

[0966] (59th embodiment)

[0967] In this embodiment, in order to prevent light reflection from pixel 102, an imaging pixel having a moth-eye structure on the semiconductor substrate 300 used to form sub-pixels 106 will be described.

[0968] Figure 123This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Specifically, the sub-pixel 106 portion of pixel 102 is magnified. Similar to the structures described in some of the embodiments above, in this embodiment, sub-pixel 106 may include, for example, a photoelectric conversion element isolation portion 110, which includes a metal film 316, an insulating film 314, and a fixed charge film 312. Sub-pixel 106 may be disposed in a semiconductor substrate 300, and wiring layer 302 may be disposed on the side of the semiconductor substrate 300 opposite to the irradiation surface.

[0969] Note that in the accompanying drawings, the moth-eye structure is relatively large and the number of irregular parts (number of cycles) is shown in a limited manner, but this embodiment is not limited to this. That is, the moth-eye structure of the sub-pixel 106, the photoelectric conversion element isolation portion 110, and the anti-reflection layer 326 are shown as examples in an easily understandable manner, and their size proportions and numbers (number of cycles, etc.) are appropriately designed.

[0970] An antireflective layer 326 is disposed on the surface of the semiconductor substrate 300 located on the lens 104 side. Since the semiconductor substrate 300 (e.g., a silicon substrate) has a large refractive index of approximately 4, reflections at the interface due to the refractive index difference are significant. For example, by forming a moth-eye structure on the surface of the semiconductor substrate 300 on the illumination surface side using micro-protrusions, the antireflective layer 326 corresponds to a continuous change in refractive index and can suppress reflections. That is, by providing an antireflective layer 326 with this moth-eye structure, the sensitivity of the imaging pixel device can be improved. As shown, an adhesive layer 330 can be disposed on the upper surface of the antireflective layer 326 to enhance adhesion to the interlayer film 306.

[0971] Furthermore, by suppressing the reflection of light from the irradiated surface, glare phenomena that occur when light reflected from the imaging element 10 is reflected again by the package or components of the electronic device and re-incidentally onto the sub-pixel 106 are mitigated. Moreover, due to the diffraction phenomenon occurring in the anti-reflection layer 326 through the periodic structure, an effect is generated in the higher-order components that enhance each other due to angle-dependent interference, thereby increasing the effective optical path length. That is, the probability of light incident on the sub-pixel 106 being photoelectrically converted within the sub-pixel 106 increases, and sensitivity can be improved.

[0972] The photoelectric conversion element isolation section 110 is disposed between the sub-pixels 106, and can prevent high-order components that are mutually enhanced at a certain angle in the anti-reflection layer 326 from mixing into adjacent sub-pixels 106. That is, crosstalk between sub-pixels 106 is suppressed, and resolution degradation of the imaging device can be suppressed.

[0973] A reflective film 328 is provided on the wiring layer 302 side (the surface opposite to the irradiation surface) of the semiconductor substrate 300. The reflective film 328 may include, for example, a metal film. For example, the metal film may be processed simultaneously with the wiring of the wiring layer. Furthermore, the reflective film 328 may, for example, function as part of a circuit. This embodiment is not limited to this, and the reflective film 328 may also be processed and provided separately from the wiring.

[0974] Note that if the reflective film 328 includes a metal film, there is a risk of plasma damage if the processing is carried out in a state of metal electro-floating. Therefore, it is desirable to ground the metal film through a contact part or the like during processing.

[0975] As another example, the reflective film 328 can be formed by a multilayer film of alternating layers of materials with high and low refractive indices.

[0976] The reflective film 328 reflects the light transmitted through the sub-pixel 106 and allows the light to re-enter the sub-pixel 106 from the wiring layer 302 side. Therefore, by providing the reflective film 328, the utilization efficiency of the light incident on the sub-pixel 106 can be improved. Therefore, by providing the reflective film 328, the sensitivity of the imaging element 10 can be improved.

[0977] As described above, in this embodiment, an anti-reflective layer 326 with a moth-eye structure can be provided for sub-pixel 106. By providing the anti-reflective layer 326, glare can be suppressed and sensitivity can be improved. Furthermore, by providing the photoelectric conversion element isolation portion 110, crosstalk can be suppressed and resolution can be improved. In addition, by providing the reflective film 328, the sensitivity of sub-pixel 106 can be improved.

[0978] Note that the reflective film 328 has been described as an example in this embodiment, but it can be configured in other embodiments. By configuring the reflective film 328 in this way, the sensitivity in other embodiments can be similarly improved.

[0979] Note that the photoelectric conversion element isolation section 110 is not limited to having the structure described in this embodiment, but may have any structure described in some of the above embodiments.

[0980] (Example 60)

[0981] For example, such as Figure 6 As shown, the light-shielding wall 108 is provided with a light-shielding material between pixels 102, so that light from adjacent pixels is not incident (no crosstalk occurs). In the third direction, the light-shielding wall 108 is disposed between the illumination surface of the semiconductor substrate 300 and the lens 104. Embodiments of the light-shielding wall 108 will be described below with some examples.

[0982] Figure 124This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 124 An example of a light-shielding wall 108 in pixel 102 is shown. Pixel 102 includes a lens 104, an inner lens 118, a sub-pixel 106, light-shielding walls 108A and 108B, and a photoelectric conversion element isolation section 110.

[0983] For example, lens 104 can be positioned at a location offset from the center of sub-pixel 106 located at the center of the pixel.

[0984] For example, the inner lens 118 can be disposed between the lens 104 and the semiconductor substrate 300 in a third-direction orientation, and the center position of the inner lens 118 can be disposed between the offset position of the lens 104 and the center of the pixel, or can coincide with one of them. In the pixel 102 described above for performing pupil correction according to the embodiment, the lens 104 and the inner lens 118 can be arranged in this manner.

[0985] Note that when pupil correction is implemented, the offset can be adjusted by the position of pixel 102 in pixel array 100. In this embodiment and the following embodiments, it will be assumed that the offset exists only in the second direction, but the embodiments are not limited to this, and there may be an offset in the first direction or the second direction, or in a combination of the first and second directions. For example, the offset can be used to achieve the same effect as the second direction. Figure 86 The effect shown is similar to that of a diffractive lens.

[0986] The light-shielding wall 108 included in pixel 102 may include light-shielding walls 108A and 108B configured as two levels to suppress crosstalk from adjacent pixels in each path. In the case of pupil correction, lens 104 and inner lens 118 are arranged such that their centers are offset.

[0987] According to the arrangement, the light-shielding wall 108B can be offset relative to the lens 104 towards the center of the pixel, or it can be formed at the same position as the lens 104. According to the arrangement, the light-shielding wall 108A can be offset by the same distance in the same direction as the inner lens 118.

[0988] From the viewpoint of light-shielding performance, it is desirable to position light-shielding walls 108A and 108B as close to each other as possible. Furthermore, it is desirable to consider process variations, such as linewidth and misalignment. Therefore, it is desirable to determine the size of the overlapping area in the plane formed by the first and second directions such that light-shielding walls 108A and 108B are always in contact with each other.

[0989] In cases where the offset for sufficient pupil correction cannot be set by defining the size of the overlapping area, the upper limit of the offset of the light-shielding wall can be increased, for example, by making the metal film 316 have a larger width in contact with the light-shielding wall 108B. Furthermore, the allowable amount of offset can be increased by increasing the thickness of the light-shielding wall 108B itself. Although the opening of the metal film 316 on the light-receiving surface may become narrower and sensitivity may be sacrificed, this method has the advantage of being performed with the same number of processes.

[0990] (Example 61)

[0991] Figure 125 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 125 Another embodiment of the light-shielding wall 108 in pixel 102 is shown. Besides Figure 124 In addition to its structure, pixel 102 also includes a light-shielding film 128.

[0992] The light-shielding film 128 is a film formed to fill the gap between the light-shielding wall 108A and the light-shielding wall 108B. For example... Figure 125 As shown, for example, a light-shielding film 128 is formed on or below the lower surface of the inner lens 118 in a third-party orientation.

[0993] and Figure 124 Unlike the overlapping of the light-shielding walls shown, light-shielding walls 108A and 108B do not necessarily overlap each other, and this embodiment can also be applied to situations where a margin is created in the arrangement of light-shielding walls 108A and 108B. That is, compared to... Figure 124 Compared to the previous case, it can produce a larger offset.

[0994] It can suppress light incident on pixel 102 through the gap between light-shielding walls 108A and 108B, and can increase the offset of pupil correction through light-shielding film 128.

[0995] (62nd embodiment)

[0996] Figure 126 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 126 A pixel 102 is shown that includes a light-shielding film 128 below the inner lens 118. That is, pixel 102 includes a light-shielding film 128 having an opening 130 between the inner lens 118 and the sub-pixel 106.

[0997] Figure 127 This is a planar cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 127The relationship between the light-shielding film 128 and the opening 130 is shown. The shaded area is the region where the light-shielding film 128 exists. The light-transmitting opening 130 is formed in this region through the light-shielding film 128.

[0998] In the above embodiment, the light-shielding film 128 is formed to fill the space between the light-shielding walls 108A and 108B. Conversely, in this embodiment, the light-shielding film 128 is not only formed between the light-shielding walls 108A and 108B, but also protrudes to the underside of the inner lens 118. The light-shielding film 128 then forms an opening 130, which is narrower than the light-transmitting area due to the light-shielding walls 108A and 108B.

[0999] By providing the opening 130, in addition to suppressing light leakage to adjacent pixels, the light-shielding film 128 can also suppress stray light (such as reflections from the light-shielding wall 108) within its own pixels. In this case, it is desirable that the opening 130 of the light-shielding film 128 be arranged so that there is no vignetting in the convergent optical path on each sub-pixel 106. As a result, the resolution of the pixels can be further improved.

[1000] (63rd embodiment)

[1001] Figure 128 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 128 A pixel 102 is shown, which includes a light-shielding film 132 located above the inner lens 118. That is, the pixel 102 includes a light-shielding film 132 with an opening 134 between the lens 104 and the inner lens 118.

[1002] Figure 129 This is a planar cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 129 The relationship between the light-shielding film 132 and the opening 134 is shown. The shaded area is the region where the light-shielding film 132 exists. The light-transmitting opening 134 is formed in this region through the light-shielding film 132.

[1003] The difference between this embodiment and the previous embodiment is that the light-shielding film 132 is formed above the inner lens 118. Similar to the light-shielding film 128 described above, the light-shielding film 132 is formed to protrude, for example, above the inner lens 118. Then, the light-shielding film 132 forms an opening 134, which is narrower than the light-transmitting area due to the light-shielding wall 108A.

[1004] By providing opening 134, stray light (such as the reflected component generated in the light-shielding wall 108) in its own pixels can be suppressed in advance. In this case, it is desirable that the opening 134 of the light-shielding film 132 is arranged so as not to excessively block the optical path converging on each sub-pixel 106 (making vignetting difficult). Therefore, the resolution of the pixels can be further improved.

[1005] (64th embodiment)

[1006] Figure 130 This is a cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 130 A pixel 102 is shown, including light-shielding films located above and below the inner lens 118. Pixel 102 includes a light-shielding film 132 forming an opening 134 and a light-shielding film 128 forming an opening 130.

[1007] Figure 131 This is a planar cross-sectional view showing an example of an imaging pixel according to an embodiment. Figure 131 The relationship between the light-shielding film 132 and the opening 134, and the relationship between the light-shielding film 128 and the opening 130 are shown. The upper right diagonal line indicates the area of ​​the light-shielding film 128, and the upper left diagonal line indicates the area of ​​the light-shielding film 132.

[1008] Note that in Figure 130 and 131 In this embodiment, the edges of the light-shielding film 128 and the light-shielding film 132 appear to overlap in the same plane, but this embodiment is not limited to this form. For example, the light-shielding film 128 may protrude more inward than the light-shielding film 132, or vice versa.

[1009] In each light-shielding film, it is desirable that the opening 134 of light-shielding film 132 and the opening 130 of light-shielding film 128 are arranged so as not to excessively block the optical path converging on the corresponding sub-pixel 106 (making vignetting less likely to occur). Light-shielding films 128 and 132 have the effect of suppressing stray light in their own pixels (e.g., reflections from light-shielding wall 108). In addition, light-shielding film 128 can have the effect of suppressing leakage to other pixels. By constructing the openings in a multi-level manner, crosstalk suppression can be enhanced and information can be obtained at a higher resolution.

[1010] Notice, Figure 124 , 125 The light-shielding films 128 and 132 in 126, 128, and 130 can be, for example, metal films, composites of, or alloys of aluminum, silver, gold, copper, platinum, molybdenum, tungsten, chromium, titanium, nickel, iron, or tellurium. Furthermore, these materials can form multilayer films, and, for example, titanium, titanium nitride, etc., can be used as barrier metals to improve adhesion. Alternatively, materials with light-absorbing properties, such as carbon black resists, can be used instead of metals.

[1011] As described above, the light-shielding wall 108 can also have various configurations. Furthermore, by providing a light-shielding film, the positional freedom of the light-shielding wall 108 and the inner lens 118 can be increased, and the effect of suppressing stray light can be achieved. By forming the pixel 102 in this manner, crosstalk can be suppressed and image information can be obtained at a higher resolution. Moreover, by providing the light-shielding wall 108 and the light-shielding films 128 and 132, glare and ghosting generated when strong light beams such as sunlight or headlights enter the imaging element 10 can be suppressed, for example.

[1012] Note that in Figure 124 , 125 In 126, 128, and 130, an inner lens 118 is provided, but this embodiment is not limited to this. Even without the inner lens 118, a light-shielding film and an opening formed by the light-shielding film can be similarly provided. Even without the inner lens 118, the light-shielding film can achieve effects such as suppressing crosstalk and stray light and improving resolution. In addition, this embodiment does not limit the number of stages; for example, a three-stage or higher structure can be used instead of a two-stage structure.

[1013] Furthermore, the shapes of openings 130 and 134 are octagons with rectangular corners cut off, depending on the shapes of the light-shielding films 128 and 132, but are not limited to this. For example, the shape can be rectangular. In addition, if the sub-pixel 106 has a hexagon, openings 130 and 134 can have hexagons or dodecagons obtained by cutting off the corners of the hexagons.

[1014] (65th embodiment)

[1015] In all the above embodiments, in addition to the photoelectric conversion element, the sub-pixel 106 may also include a storage region and a transfer transistor that transfers the signal charge accumulated in the photoelectric conversion element to the storage region. This configuration enables global shutter operation without focal plane distortion.

[1016] Figure 132 This is a cross-sectional view showing an example of imaging pixels according to an embodiment. Note that this figure is shown in a simpler manner than the figures for each of the embodiments described above, in order to facilitate understanding of its main points. More specifically, Figure 132 This is a diagram illustrating the structure of the sub-pixel 106 according to this embodiment.

[1017] Similar to some of the embodiments described above, the sub-pixel 106 can be isolated by, for example, a photoelectric conversion element isolation portion 110 including a fixed charge film 312, an insulating film 314, and a metal film 316. As another example, the photoelectric conversion element isolation portion 110 may have the structure described in other embodiments, and the combination is not limited.

[1018] In this embodiment, sub-pixel 106 includes a light receiving area, a storage area 332, and a transistor 334.

[1019] Storage region 332 is configured to be adjacent to light-receiving region. Storage region 332 is formed of a semiconductor layer that retains the charge generated by light received in sub-pixel 106 until a request is made. For example, storage region 332 may be formed to be surrounded by a fixed charge film 312, an insulating film 314, and a metal film 316. For example, storage region 332 may be formed to have a surface covered with the metal film 316, fixed charge film 312, and insulating film 314 on the side of lens 104, and light from lens 104 is not directly incident.

[1020] Transistor 334 transfers the charge stored in sub-pixel 106 to storage region 332 at a predetermined time. More precisely, Figure 132 The transistor 34 shown corresponds to the gate electrode of the transistor that transfers charge from the light-receiving region of the sub-pixel 106 to the storage region 332. By applying an appropriate voltage to the gate electrode, the light-receiving region and the storage region 332 are electrically connected, and the analog signal of photoelectric conversion is output to the storage region 332 at a potential reduced to a predetermined potential.

[1021] For example, imaging element 10 performs a raster scan, that is, it causes multiple photoelectric conversion elements to scan the pixel array 100 to acquire light intensity. In this case, when imaging element 10 acquires analog signals from charge through scanning for each pixel 102, the timing of acquiring the analog signals varies depending on the location of the photoelectric conversion elements. Therefore, focal plane distortion occurs between photoelectric conversion elements that perform scans earlier and those that perform scans later, and this distortion forms an image based on information about the light acquired at different times.

[1022] To avoid this focal plane distortion, in the photoelectric conversion element that receives light, the charge in the storage region 332 is set to a predetermined level at a predetermined time, and then the charge stored in the photoelectric conversion element is transferred to the storage region 332 via transistor 334 at the predetermined time. Afterwards, by scanning the storage region 332 of the sub-pixel 106 to acquire an analog signal, focal plane distortion can be avoided.

[1023] As described above, according to this embodiment, focal plane distortion can be suppressed by setting the storage area 332. When this embodiment is used in fingerprint sensors or the like, image quality degradation can be avoided by using a global shutter drive to address focal plane distortion, or fingerprint shape blurring caused by finger movement on the imaging device can be avoided by using a rolling shutter, thereby improving authentication accuracy.

[1024] By using a global shutter, authentication can be performed instantaneously even when the finger is moving, and for example, fingerprint authentication is achieved through a flip operation in electronic device 1. As long as authentication can be performed through a flip operation, for example, the imaging element 10 can be configured to be elongated in either the first or second direction of the display unit. In this case, by providing instructions prompting the user to perform a flip operation approximately perpendicular to the azimuth angle of the arrangement, the authentication area can be expanded while simultaneously reducing the occupied area. It is desirable to set the length of the imaging element 10 in the long side direction where light can be received to allow for capturing as many images as possible from one end of the display viewing angle to the other, since the position where the flip operation is performed is uncertain.

[1025] Note that all embodiments of the present invention are not limited to authentication applications and can be used, for example, for non-contact proximity imaging. More specifically, the embodiments can also be applied to cameras for example, performing ultra-macro close-up photography, iris authentication, reading of minimal barcodes, and inspection by machine vision devices. Furthermore, by combining the embodiments with optical lenses, it can also be used for general camera applications, such as digital cameras and video cameras.

[1026] Furthermore, as an electronic device with motion capture capabilities, it can treat the movements of a subject, such as a finger, as an optical image including the depth direction (described later), and input operation commands. These operation commands become more complex as functional requirements necessitate, but if routine operations are made into a common language, it could also become a new way to communicate with people with hearing impairments.

[1027] By applying the global shutter drive according to this embodiment to these applications, various image quality problems in rolling shutter drives can be solved, such as the impact of camera shake or subject movement on image distortion and image quality, or the phenomenon of flash being reflected in a band by the flash (so-called flash band).

[1028] (66th embodiment)

[1029] The electronic device 1 according to this embodiment includes the imaging element 10 described in the above embodiments, and has authentication and anti-spoofing functions primarily targeting a living finger as the subject. Although a finger is used as a specific example, this embodiment can be applied to other body parts such as the palm, and is not limited thereto.

[1030] [Manufacturing Method]

[1031] Next, some processes will be described with reference to some structures of the semiconductors illustrated in each of the above embodiments. Note that in the process description, the dimensions of layers and films are emphasized for illustrative purposes. Therefore, the proportions in the figures are not accurate and need to be properly designed and formed.

[1032] First, some overall methods (semiconductor processes) for manufacturing the imaging element 10 will be explained.

[1033] (67th embodiment)

[1034] First, refer to Figures 133 to 13 9. Manufacturing instructions Figure 93 The method shown is for sub-pixel 106. Figure 133 , 134 Models 135, 136, 137A (137B), 138A (138B), and 139A (139B) illustrate the manufacturing process. Figure 93 A view of the continuous process of subpixel 106 shown.

[1035] In the method for manufacturing an imaging device according to this embodiment, sub-pixels 106, separated by element isolation regions of p-type semiconductor regions, are formed in the region where a pixel region of a semiconductor substrate (e.g., silicon) 300 is to be formed. The sub-pixels 106 are formed having pn junctions that include n-type semiconductor regions and p-type semiconductor regions in contact with the n-type semiconductor regions and facing the front and rear surfaces of the semiconductor substrate 300 over the entire thickness direction of the semiconductor substrate 300.

[1036] like Figure 133 As shown, for example, a desired impurity region (p-type well region 310) is formed by ion implantation of the desired impurity from the front surface side of the semiconductor substrate 300 using a resist 350 as a mask. A p-type semiconductor well region (well region 310) is formed on the substrate surface corresponding to each pixel, contacting the element isolation region, and each of a plurality of pixel transistors is formed in the well region 310. Each pixel transistor includes a source region and a drain region, a gate insulating film, and a gate electrode.

[1037] Additionally, a wiring layer 302, comprising aluminum or copper, is formed on the substrate surface through an interlayer insulating film (e.g., silicon oxide film, not shown). Through-interconnects are formed between the pixel transistors formed on the substrate surface and the wiring layer, and are electrically connected to drive the imaging element. Interlayer insulating films, such as silicon oxide films, are stacked on the wiring. The interlayer insulating films are planarized by chemical mechanical polishing (CMP) to make the surface of the wiring layer substantially flat. Wiring is repeatedly formed on the wiring, simultaneously connecting to the next layer of wiring through through-interconnects, and each layer of wiring is formed sequentially.

[1038] Next, as Figure 134 As shown, the semiconductor substrate 300 is inverted and bonded to the support substrate 352 by means of plasma bonding or the like. Then, the substrate is thinned from the rear surface side by, for example, wet etching or dry etching.

[1039] For example, such as Figure 135 As shown, the substrate is thinned to a desired thickness using CMP. Depending on the identified wavelength region, the desired substrate thickness is, for example, in the range of 2 to 6 μm when only the visible light region is detected, or in the range of 3 to 15 μm when the near-infrared region is also detected. During this process, for example, a well region 310 can be formed on the surface of the pixel. Furthermore, as another example, in... Figure 133 Prior to the process shown, photolithography and ion implantation can be repeated to form the pixel potential, and as... Figure 135 As shown, a well region 310 can be formed on the surface. This also applies to the following embodiments.

[1040] Next, in the photoelectric conversion element isolation section 110, trenches can be formed in the semiconductor substrate 300 using a so-called Bosch process. In the Bosch process, for example, etching and deposition are alternately repeated for a resist punching pattern, in which a portion of the boundary of each pixel or the boundary of each sub-pixel is open. If the resist's etch resistance is insufficient, a hard mask with a high selectivity, such as silicon nitride or silicon oxide, can be pre-formed, and the resist trench pattern can be transferred and etched through the hard mask. After trenching, the hard mask and foreign matter can be removed using a chemical solution or the like.

[1041] Next, as Figure 136 As shown, a fixed charge film 312 and an insulating film 314 are formed. This formation is performed, for example, by forming films on the light-receiving surface or in trenches of the semiconductor substrate 300 using methods such as chemical vapor deposition (CVD), sputtering, or atomic layer deposition (ALD).

[1042] The thickness of the fixed-charge film 312 directly above the sub-pixel 106 is desired to increase the transmittance of light with respect to the refractive index and extinction coefficient of the material at a defined wavelength. For the film in contact with the Si interface, it is desirable to use an ALD that can achieve good coverage at the atomic level. When the insulating film 314 (e.g., silicon oxide formed by ALD) is thinned, film peeling, known as blistering, is prone to occur; therefore, its thickness is preferably at least 20 nm, and more preferably at least 50 nm.

[1043] Furthermore, the light-shielding performance can be enhanced by embedding the metal film 316 into the gaps of the insulating film 314 in the trench portion using methods such as CVD, sputtering, or ALD. Note that when processing is performed in a metal-floating state, there is a risk of plasma damage. Therefore, as... Figure 137A and 137BAs shown, it is desirable to transfer a resist perforation pattern having a width of, for example, several μm in a region outside the imaging element 10, forming grooves by anisotropic etching or wet etching to expose the surface of the semiconductor substrate 300, and then as... Figure 138A and 138B As shown, the film is formed by grounding the metal film 316 to the semiconductor substrate 300.

[1044] Here, Figure 137A and 138A It is a region formed as pixel 102, and Figure 137B and 138B This refers to the area that was not formed as pixel 102 but instead formed as a black reference pixel. This also applies to... Figure 139A and 139B .

[1045] For example, it is desirable to set the semiconductor substrate region to which the metal film 316 is grounded to a ground potential to serve as a p-type semiconductor region. Multiple metal films 316 can be stacked. For example, titanium or titanium nitride of about 30 nm can be deposited by sputtering as an adhesive layer to bond with the insulating film 314, and then a tungsten film can be formed.

[1046] In cases where the metal film 316 not only constitutes the isolation section 110 of the photoelectric conversion element but also shields against light to cover the black reference pixel area and the peripheral circuit area, it is desirable to set the film thickness according to the required light-shielding performance. Depending on the application of the electronic device, for example, if light-shielding performance below -160dB is required, it is desirable to use tungsten with a thickness of 200nm or more.

[1047] like Figure 139A and 139B As shown, for the area of ​​sub-pixel 106, as well as the pad portion and scribing portion, a resist perforation pattern can be formed on the metal film 316, and the metal film 316 can be partially removed by anisotropic etching or other methods.

[1048] (Example 68)

[1049] Regarding the method described above for manufacturing the isolation section 110 of the photoelectric conversion element, please refer to... Figures 133 to 139B An example of a manufacturing method in which trenches are not formed in the semiconductor substrate 300 will be described. Here, a modified example of forming trenches in the semiconductor substrate from an irradiated surface and a modified example of forming trenches in the semiconductor substrate from a side opposite to the irradiated surface will be described. Descriptions repeated in the above embodiments will be omitted below.

[1050] Note that in the following embodiments, a grounding state is not shown during the formation of the metal film 316, but it is assumed that grounding is properly performed in each step. Furthermore, electrostatic discharge (ESD) of each component can be prevented, for example, by other means instead of grounding.

[1051] Figures 140 to 145 An example of a manufacturing method is shown, in which trenches are formed in a semiconductor substrate 300 from an irradiated surface and a fixed charge film 312 and an insulating film 314 are embedded. For example, the pixel 102 formed by this process has Figure 91 The structure shown.

[1052] Figure 140 The previous embodiment is shown. Figure 135 The subsequent process. Figure 135 Following this process, a hard mask 354 is stacked, and a resist 350 is formed on the hard mask 354 in the area where the sub-pixel 106 is to be formed. That is, the resist 350 is formed to etch the semiconductor substrate 300 only in the area of ​​the trench.

[1053] exist Figure 140 In this state, a photoresist 350 is used to remove the hard mask 354 in the upper portion of the trench. For example, the hard mask 354 comprises silicon nitride or silicon oxide. Figure 141 As shown, the pattern of the resist 350 is used to etch the hard mask 354 to transfer the pattern of the resist 350 to the hard mask 354.

[1054] Next, as Figure 142 As shown, trenches are formed. For example, trenches are formed by etching areas of the semiconductor substrate 300 that are not covered by the hard mask 354 using a Bosch process or similar method.

[1055] Next, as Figure 143 As shown, hard mask 354 is removed using a chemical solution.

[1056] Next, as Figure 144 As shown, a fixed charge film 312 and an insulating film 314 are formed.

[1057] Next, as Figure 145 As shown, a metal film 316 is formed on the trench through an insulating film 314 and a fixed charge film 312.

[1058] (Example 69)

[1059] Figures 146 to 149 An example of a manufacturing method is shown, in which trenches are formed in a semiconductor substrate 300 from an irradiated surface and a fixed charge film 312, an insulating film 314, and a metal film 316 are embedded. For example, the pixel 10 formed by this process has... Figure 7 The structure shown.

[1060] Figure 146 The previous embodiment is shown. Figure 143 The subsequent process. Figure 143 Following this process, a fixed charge film 312 and an insulating film 314 are formed. This formation is performed, for example, by CVD, ALD, or sputtering. During this process, the fixed charge film 312 and the insulating film 314 are also formed in the trench. Unlike the embodiments described above, when forming the oxide film, etc., a margin is left for forming the metal film 316 in a later process, instead of filling the interior of the trench with the insulating film 314.

[1061] Next, as Figure 147 As shown, a metal film 316 is formed on the insulating film 314. A metal film 316 is also formed in the trench.

[1062] Next, as Figure 148 As shown, resist 350 is formed on the trench.

[1063] Then, as Figure 149 As shown, the metal film 316 is removed based on the pattern of the resist 350, and then the resist 350 is removed, so that the metal film 316 forms a shape in which the head protrudes from the semiconductor substrate 300 (becoming a hammer shape).

[1064] It is generally known that when the photoelectric conversion region is opened by anisotropic etching, the interface state is degraded by ultraviolet light emission from the plasma during the processing (e.g., see Y. Ichihashi et al., "Journal for Vacuum Science & Technology", B28 (2010) 577-; T. Yunogami et al., "Japan Journal of Applied Physics", 28 (1989) 2172-).

[1065] According to Figures 140 to 145 The previous embodiments shown and Figures 146 to 149 In the method for manufacturing the isolation portion 110 of the photoelectric conversion element shown in this embodiment, the metal film 316 is manufactured to be wider than the processing width of the trench formed in the semiconductor substrate 300. This ensures that the interface of the trench sidewalls with the metal film 316 is always protected from ultraviolet light emission from the plasma during processing, and suppresses the deterioration of dark current and white point characteristics. Furthermore, it also has the advantage of improved crosstalk and angular resolution as the linewidth of the metal film 316 increases.

[1066] (70th embodiment)

[1067] Figures 150 to 151An example of a manufacturing method is shown, in which trenches are formed in a semiconductor substrate 300 from an irradiated surface and a fixed charge film 312, an insulating film 314, and a metal film 316 are embedded. For example, a pixel 102 formed by this method has Figure 115 The structure shown.

[1068] Figure 150 The previous embodiment is shown. Figure 147 The subsequent process. Figure 147 After the process, similar to Figure 148 A resist 350 is formed on the trench. Resist 350 has a higher... Figure 148 In cases where the resist is narrower, for example, the size of the resist 350 can allow a metal film 316 having the same size as the metal film 316 formed in the trench to remain on the upper surface of the semiconductor substrate 300 by a process such as etching in a subsequent process.

[1069] Then, as Figure 151 As shown, the metal film 316 is removed based on the pattern of the resist 350, and then the resist 350 is removed, so that the metal film 316 is formed to protrude to the upper surface of the semiconductor substrate 300.

[1070] Figure 151 and 152 The method shown for manufacturing the isolation portion 110 of the photoelectric conversion element differs from the method of the aforementioned embodiment in that the metal film 316 is formed narrower than the processing width of the trench. Because the trench sidewall interface is exposed to... Figure 152 There are concerns about dark current and white spot degradation due to ultraviolet light exposure of the plasma during processing, but it has the advantages of suppressing vignetting caused by the metal film 316 and high sensitivity.

[1071] Note that, for example, by providing a film that absorbs ultraviolet light between the metal film 316 and the semiconductor substrate 300, interface damage during the etching process can be eliminated. For example, Ta2O5 (tantalum pentoxide), mentioned as one of the materials for the fixed charge film 312, has a measured extinction coefficient k of 0.000 and k = 0.775 at a wavelength of 250 nm.

[1072] Figure 152 The transmittance calculation results are shown. By forming Ta2O5 into a film with a thickness of at least 15 nm, preferably 60 nm, dark current and white spot degradation can be suppressed with almost no degradation of visible light sensitivity. The Ta2O5 mentioned here is just an example; various combinations of materials that suppress ultraviolet light while allowing visible light to pass through, as well as film thickness settings, can be considered.

[1073] (71st embodiment)

[1074] Figure 153A ,153B Examples 153C, 154A, 154B, and 154C illustrate a manufacturing method in which trenches are formed in a semiconductor substrate 300 from an irradiated surface and a fixed charge film 312, an insulating film 314, and a metal film 316 are embedded. For example, a pixel 102 formed by this process has… Figure 113 The structure shown.

[1075] Figure 153A and 154A This is a view showing pixel 102 that receives light. Figure 153B and 154B This is a view showing pixel 102 in the black reference pixel area, and Figure 153C and 154C This is a view showing the grounding area outside the pixel area.

[1076] Figure 153A , 153B And 153C shows the corresponding Figure 147 The process. In Figure 153A In the middle, in pixel 102 that receives light, with Figure 147 Similarly, a metal film 316 is formed, and no further treatment is performed before the next process.

[1077] In the black reference pixel area, such as Figure 153B As shown, resist 350 is formed on the metal film 316 over the entire surface.

[1078] In the grounding region outside the pixel region, such as Figure 153C As shown, resist 350 is as follows Figure 153B As shown, a metal film 316 is formed on the entire surface. For example, the process is similar to... Figure 138A The process of state formation.

[1079] Next, as Figure 154A As shown, the metal film 316 is removed by etching or grinding. Figure 154A As shown, no metal film 316 is disposed on the insulating film 314 in the light-receiving area of ​​the sub-pixel 106 in the region of pixel 102. At the same time, the metal film 316 is embedded in the photoelectric conversion element isolation section 110, so that the metal film 316 is substantially flush with the surrounding insulating film 314.

[1080] In the black reference area, such as Figure 154B As shown, the resist 350 is removed after the process of removing the metal film 316. Therefore, in areas different from pixel 102, the metal film 316 is not removed and the surface is covered by the metal film 316.

[1081] In the grounding region outside the pixel region, such as Figure 154C As shown, the execution process causes the metal film 316 to... Figure 154B As shown, it remains on the entire surface. [1...

Claims

1. An imaging device comprising: A sub-pixel includes a photoelectric conversion element and is configured to receive light incident at a predetermined angle and output an analog signal based on the intensity of the received light; A pixel, comprising a plurality of said sub-pixels, a lens that converges externally incident light onto the sub-pixels, and a photoelectric conversion element isolation portion that does not propagate information about the intensity of light acquired in the photoelectric conversion element to adjacent photoelectric conversion elements, and further comprising a light-shielding wall for blocking light incident on the lens of another pixel; and A pixel array comprising multiple of the aforementioned pixels, The photoelectric conversion element isolation section includes a groove starting from the non-illuminated surface side of the semiconductor substrate, a portion of which has a height difference, includes a vertical transistor, and has a rear-surface illuminated structure. In the cross-sectional view, the groove has a first width on the non-irradiated surface side of the semiconductor substrate and a second width on the irradiated surface side of the semiconductor substrate, the second width being smaller than the first width.

2. The imaging device according to claim 1, wherein... The lens is a recirculation lens, and there is a height difference between the lens and the adjacent lens in terms of the recirculation blocking portion.

3. The imaging device according to claim 1, wherein... The pixel also includes an inner lens located between the lens and the photoelectric conversion element.

4. The imaging apparatus according to claim 1, wherein The lens is arranged such that the center position of the lens is offset from the center position of the corresponding pixel based on the position of the pixel in the pixel array.

5. The imaging apparatus according to claim 1, wherein... The pixel includes a plasma filter for at least one of the sub-pixels.

6. The imaging apparatus according to claim 1, wherein The pixel includes at least two types of color filters between the lens and the photoelectric conversion element.

7. The imaging apparatus according to claim 1, further comprising: A storage region temporarily stores the charge converted from light in the photoelectric conversion element.

8. The imaging apparatus according to any one of claims 1 to 6, wherein The isolation section of the photoelectric conversion element includes an impurity layer formed by solid-phase diffusion.

9. The imaging apparatus according to any one of claims 1 to 6, wherein The pixel has at least two different sizes of sub-pixels.

10. An electronic device comprising: A sub-pixel includes a photoelectric conversion element and is configured to receive light incident at a predetermined angle and output an analog signal based on the intensity of the received light; A pixel includes a plurality of said sub-pixels, a lens that converges externally incident light onto the sub-pixels, and a photoelectric conversion element isolation portion that does not propagate information about the intensity of light acquired in the photoelectric conversion element to adjacent photoelectric conversion elements, and also includes a light-shielding wall for blocking light incident on the lens of another pixel. and An imaging element comprising a pixel array, wherein the pixel array comprises a plurality of said pixels, The photoelectric conversion element isolation section includes a groove starting from the non-illuminated surface side of the semiconductor substrate, a portion of which has a height difference, includes a vertical transistor, and has a rear-surface illuminated structure. In the cross-sectional view, the groove has a first width on the non-irradiated surface side of the semiconductor substrate and a second width on the irradiated surface side of the semiconductor substrate, the second width being smaller than the first width.

11. The electronic device of claim 10, further comprising: A signal processing device that synthesizes the output of multiple sub-pixels acquired by the imaging element and acquires three-dimensional stereoscopic information of the subject.

12. The electronic device of claim 10, further comprising: A signal processing device that synthesizes the output of a plurality of said sub-pixels acquired by said imaging element and refocuses the subject image.

13. The electronic device of claim 10, further comprising: The display unit has the imaging element arranged on the side of the display unit opposite to the display surface. Address storage unit for sub-pixels whose light from the subject is blocked by the light-emitting element of the display unit; and A signal processing device configured to synthesize a subpixel image by excluding signals from the shaded subpixels.

14. The electronic device of claim 10, further comprising: A personal authentication device includes a storage unit that extracts features from an individual fingerprint image acquired by the imaging element and stores the features in a database, and is configured to acquire a fingerprint image of a subject during an authentication operation, extract the features, compare the features with the database, and make a determination.

15. The electronic device according to claim 14, wherein The method used to obtain the fingerprint image is a flipping operation.

16. The electronic device of claim 10, further comprising: A personal authentication device includes a storage unit that extracts features from a personal vein image acquired by the imaging element and stores the features in a database, and is configured to acquire the vein image of a subject during an authentication operation, extract the features, compare the features with the database, and make a determination.

17. The electronic device according to claim 16, wherein The feature of the vein image is three-dimensional information.

18. The electronic device according to any one of claims 10 to 17, further comprising: The anti-impersonation function is used to compare the spectral information of the subject acquired by the imaging element with the unique rising spectrum of human skin near a wavelength of 590nm, and to determine whether the subject is a living body.

19. The electronic device according to any one of claims 10 to 17, further comprising: Anti-spoofing function, which is used to detect vein pulsation from multiple image differences of vein images acquired by the imaging element, and to determine whether the vein image is a live vein image.

Images