Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K39/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic radiation-sensitive element covered by group H10K30/00
  • H10K39/30—Devices controlled by radiation
  • H10K39/32—Organic image sensors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
  • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
  • H01L27/144—Devices controlled by radiation
  • H01L27/146—Imager structures
  • H01L27/14643—Photodiode arrays; MOS imagers
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/003—Light absorbing elements
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/30—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising bulk heterojunctions, e.g. interpenetrating networks of donor and acceptor material domains

Definitions

• the present application relates to an image sensor.
• An image acquisition system comprising an image sensor generally further comprises an optical system interposed between the sensitive part of the image sensor and the object to be imaged and which makes it possible to form a clear image of the object to be imaged on the sensitive part of the image sensor.
• a conventional optical system can comprise a succession of fixed or movable lenses along the optical axis of the image acquisition system.
• An object of one embodiment is to increase the sharpness of the image acquired by the image sensor of an image acquisition system in the absence of an optical system forming a sharp image of the object to be imaged on the sensitive part of the image sensor.
• Another object of an embodiment is that the area of the sensitive part of the image sensor is greater than one square centimeter.
• Another object of an embodiment is that the distance between the object to be imaged and the sensitive part of the image sensor is less than a centimeter.
• One embodiment provides an image sensor comprising organic photodetectors and an angular filter less than 20 ⁇ m from the photodetectors.
• An embodiment also provides a method of manufacturing an image sensor comprising the formation of organic photodetectors and an angular filter less than 20 ⁇ m from the photodetectors.
• the image sensor comprises a face intended to receive radiation, said photodetectors being configured to detect said radiation, the angular filter covering the image sensor and being configured to block the rays of said radiation the incidence of which with respect to a direction orthogonal to the face is greater than a threshold and to allow rays of said radiation to pass, the incidence of which with respect to a direction orthogonal to the face is less than the threshold.
• the angular filter comprises a layer opaque to said radiation and a matrix of openings formed in the layer, the openings being filled with air or a material at least partially transparent to said radiation.
• the ratio between the height of the opening, measured perpendicular to the face, and the width of the opening, measured parallel to the face varies from 1 to 10.
• the openings are arranged in rows and in columns, the pitch between adjacent openings of the same row or of the same column varying from 10 ⁇ m to 60 ⁇ m.
• the height of each opening measured in a direction orthogonal to the face, varies from 1 ⁇ m to 1 mm.
• the width of each opening, measured parallel to the face varies from 5 ⁇ m to 30 ⁇ m.
• the image sensor comprises a substrate, a first stack of layers comprising thin-film transistors and a second stack of layers comprising the photodetectors.
• the angular filter is located in the substrate, between the substrate and the first stack, in the first stack or between the first stack and the second stack.
• the photodetectors are connected to the transistors of the first stack by vias passing through the angular filter.
• the image sensor comprises an encapsulation film impermeable to oxygen and to humidity covering the photodetectors and the angular filter covers the photodetectors, on the side of the photodetectors opposite to the first stack, between the photodetectors and the encapsulation film.
• the image sensor or the method further comprises lenses covering the openings.
• the photodetectors comprise organic photodiodes.
• FIG. 1 represents an electric diagram of an example of an image sensor
• FIG. 2 is a top view, partial and schematic, of an example of the image sensor of FIG.
• Figure 3 is a sectional view, partial and schematic, of the image sensor of Figure 2;
• FIG. 4 is a sectional view, partial and schematic, of an example of an image sensor comprising an angular filter
• Figure 5 is a sectional view, partial and schematic, of an embodiment of an image sensor comprising an angular filter
• Figure 6 is a sectional view, partial and schematic, of an embodiment of the angular filter shown in Figure 5;
• Figure 7 is a top view, partial and schematic, of the angular filter shown in Figure 6;
• FIG. 8 is an enlarged, partial and schematic sectional view of another embodiment of an angular filter
• FIG. 9 is an enlarged, partial and schematic sectional view of another embodiment of an angular filter.
• FIG. 10 is a sectional view, partial and schematic, of another embodiment of an image sensor comprising an angular filter
• Figure 11 is a sectional view, partial and schematic, of another embodiment of an image sensor comprising an angular filter
• FIG. 12 is a sectional view, partial and schematic, illustrating a step of an embodiment of a method of manufacturing the image sensor shown in FIG. 5;
• FIG. 13 illustrates another step of the method
• FIG. 14 illustrates another step of the method
• FIG. 15 illustrates another step of the method
• FIG. 16 illustrates another step of the method
• FIG. 17 illustrates another step of the method
• FIG. 18 illustrates another step of the method.
• an optoelectronic component is said to be organic when the active region of the optoelectronic component is predominantly, preferably entirely, at least one organic material or a mixture of organic materials.
• the transmittance of a layer corresponds to the ratio between the intensity of the radiation leaving the layer and the intensity of the radiation entering the layer, the rays of the incoming radiation being perpendicular to the layer.
• a layer or a film is said to be opaque to radiation when the transmittance of the radiation through the layer or the film is less than 10%.
• a layer or a film is said to be transparent to radiation when the transmittance of the radiation through the layer or the film is greater than 10%.
• the refractive index of a material corresponds to the refractive index of the material for the range of wavelengths of the radiation picked up by the image sensor. Unless otherwise indicated, the refractive index is considered substantially constant over the range of wavelengths of the useful radiation, for example equal to the average of the index refraction over the wavelength range of the radiation picked up by the image sensor.
• visible light is called electromagnetic radiation whose wavelength is between 400 nm and 700 nm and infrared radiation is called electromagnetic radiation whose wavelength is between 700 nm and 1 mm.
• infrared radiation one distinguishes in particular the near infrared radiation, the wavelength of which is between 700 nm and 1.4 ⁇ m.
• FIG. 1 partially and schematically represents an image sensor 10.
• the image sensor 10 comprises a matrix 11 of detection elements 12, referred to below as a detection matrix.
• the detection elements 12 can be arranged in rows and columns.
• Each detection element 12 comprises a photodetector 14, for example a photodiode, and a selection element 16, for example a transistor whose source or drain is connected to a first electrode of photodiode 14, for example the cathode.
• the image sensor 10 comprises a selection circuit 18 comprising, for each row, a conductive track 20 connected to the gates of the selection transistors 16.
• the image sensor 10 further comprises a read circuit 22 comprising, for each column, a conductive track 24 connected to the source or to the drain of the column selection transistors 16.
• the second electrodes of the photodiodes 14, for example the anodes can be connected by conductive tracks 26 to a source 28 of a reference potential.
• Figures 2 and 3 are respectively a top view and a side section, partial and schematic, of an example of a detection matrix 30 whose diagram electrical equivalent can correspond to the detection matrix 11 shown in FIG. 1.
• the detection matrix 30 comprises from bottom to top in Figure 3:
• a support 31 which may have a single-layer or multi-layer structure and which, in FIG. 3, comprises a substrate 32 covered with an intermediate layer 33;
• a stack 35 in which photodetectors 38 are formed for example organic photodiodes, also called OPD (acronym for Organic PhotoDiode), the stack 35 comprising lower electrodes 36, each electrode 36 being connected to one of the transistors T, a layer 37 in contact with the electrodes 36 and in which the active regions of the photodiodes 38 are formed and an upper electrode 40 in contact with the layer 37, only two photodiodes 38 and two electrodes 36 being shown in FIG. 3;
• OPD organic photodiodes
• Each photodiode 38 comprises an active region 46 corresponding to the portion of the layer 37 interposed between the electrode 36 associated with the photodiode 38 and the electrode 40.
• each organic photodiode 38 may comprise a first layer interface in contact with one of the electrodes 36, the active region 46 in contact with the first interface layer, and a second interface layer in contact with the active region 46, the electrode 40 being in contact with the second interface layer.
• the stack 34 comprises: - electrically conductive tracks 50, 51 resting on the support 31, the tracks 50 forming the gate conductors of the transistors T, which corresponds to the tracks 20 of the equivalent electric diagram of FIG. 1, and the tracks 51 being connected to the drains or at the sources of the transistors T;
• a layer 52 of a dielectric material covering the tracks 50, 51 and the support 31 between the tracks 50, 51 and forming the gate insulators of the transistors T;
• the transistors T are shown with a so-called low gate structure.
• the transistors T can be of the high gate type.
• this interface layer may correspond to an electron injecting layer or to an injecting layer of holes.
• the output work of each interface layer is adapted to block, collect or inject holes and / or electrons depending on whether this interface layer acts as a cathode or an anode. More precisely, when the interface layer acts as an anode, it corresponds to a layer injecting holes and blocking electrons.
• the output work of the interface layer is then greater than or equal to 4.5 eV, preferably greater than or equal to 5 eV.
• the interface layer acts as a cathode, it corresponds to an electron injecting and hole blocking layer.
• the output work of the interface layer is then less than or equal to 4.5 eV, preferably less than or equal to 4.2 eV.
• the electrode 36 or 40 advantageously plays directly the role of an electron injecting layer or of an injecting layer of holes for the photodiode 38 and it is not necessary to provide, for the photodiode 38 , of interface layer in contact with active region 46 and playing the role of an electron injecting layer or an injecting layer of holes.
• Figure 4 is a side section of an exemplary image sensor 70.
• the image sensor 70 comprises the detection matrix 30 shown in Figures 2 and 3 and further comprises an angular filter 72 corresponding to an opaque film 74 traversed by openings 76.
• the opaque film 74 is fixed to the coating 44 by lamination using a layer of an adhesive material 78.
• the angular filter 72 is adapted to filter the light rays according to their incidence in a manner to improve the sharpness of the images acquired by the image sensor. The angle of incidence beyond which the incident rays are blocked depends in particular on the ratio between the height and the width of the openings 76.
• the thickness of the upper electrode 40 can be of the order of 500 nm.
• the thicknesses of the layers of adhesive material 42, 78 may be of the order of 25 ⁇ m.
• the thickness of the coating 44 may be of the order of 50 ⁇ m.
• a drawback of the image sensor 70 shown in FIG. 4 is then that the distance between the angular filter 72 and the photodiodes 38 is generally greater than 100 ⁇ m. This may require the use of a high aspect ratio for the apertures 76 of the angular filter 72 and complicate the manufacture of the angular filter 72. Furthermore, the use of a high aspect ratio results in a reduction of the transmittance of the angular filter 72, which may not be desirable.
• a drawback of the image sensor 70 is then that the alignment of the angular filter 72 relative to the photodiodes 38 requires the implementation of additional assembly techniques, which increases the manufacturing costs of the image sensor.
• Figure 5 is a side section of an embodiment of an image sensor 80.
• the image sensor 80 comprises the detection matrix 30 shown in Figures 2 and 3, with the difference that an angular filter 82 is disposed between the substrate 32 and the stack 34.
• the angular filter 82 is disposed between the substrate 32 and the intermediate layer 33.
• the image sensor 80 is intended to be illuminated on the side of the substrate 32.
• the conductive tracks 50 connected to the gates of the transistors T extend between the columns of photodiodes 38
• the conductive tracks 56 connected to the sources of the transistors T extend between the rows of photodiodes 38.
• the tracks 50, 56 may not be transparent to the radiation picked up by the photodiodes 38 since they do not cover the photodiodes 38.
• the angular filter 82 corresponds to a layer 84, opaque to the radiation picked up by the photodetectors 38, and crossed by openings 86.
• the angular filter 82 comprises a lower face 88 oriented towards the side of the substrate 32 and an upper face 90 oriented on the side of the photodiodes 38.
• the faces 88, 90 are preferably substantially flat.
• the distance between the upper face 90 of the angular filter 82 and the photodiodes 38 is less than 20 ⁇ m, preferably less than 10 ⁇ m, more preferably less than 6 ⁇ m.
• the angular filter 82 is adapted to filter the incident rays as a function of the incidence of the rays relative to the lower face 88 of the angular filter 82, in particular so that each photodetector 38 receives only the rays whose incidence relative to to an axis perpendicular to the lower face 88 of the angular filter 82 is less than a maximum angle of incidence of less than 45 °, preferably less than 30 °, more preferably less than 20 °, even more preferably less than 10 °.
• the angular filter 82 is adapted to block the incident rays whose incidence relative to an axis perpendicular to the lower face 88 of the angular filter 82 is less than the maximum angle of incidence.
• the detection matrix 30 may further comprise a polarizing filter, arranged for example on the coating 44 or on the substrate 32 depending on the illumination of the image sensor.
• the detection matrix 30 may further comprise color filters facing the photodetectors 38 to obtain a wavelength selection of the radiation reaching the photodetectors 38.
• Figures 6 and 7 are respectively a sectional view and a top view, partial and schematic, of an embodiment of the angular filter 82.
• the layer 84 is opaque to the radiation detected by the photodetectors 38, for example absorbent and / or reflective with respect to the radiation detected by the photodetectors 38. According to one embodiment, the layer 84 is absorbent in the visible and / or the near infrared and / or the infrared.
• the openings 86 are shown with a square cross section.
• the cross section of the openings 86 in the top view may be circular, oval or polygonal, for example triangular, square or rectangular.
• the openings 86 are arranged in rows and in columns.
• the openings 86 can have substantially the same dimensions. Called “w” the width of an opening 86 measured in the direction of the rows or columns. According to one embodiment, the openings 86 are arranged regularly according to the rows and according to the columns. Called “p” the repetition pitch of the openings 86, that is to say the distance in top view between the centers of two successive openings 86 of a row or of a column.
• the angular filter 82 shown in Figures 6 and 7 only allows the rays of the incident radiation to pass, the incidence of which relative to the substrate 32 is less than a maximum angle of incidence a, which is defined by the relation (1 ) next : [Math 1]
• the zero incidence transmittance of the angular filter 82 is proportional to the ratio of the transparent area in top view to the absorbent area of the angular filter 82. For low light level applications, it is desirable that the transmittance be maximum to increase the light level. quantity of light collected by the image sensor 80. For high light level applications, the transmittance can be reduced so as not to dazzle the image sensor 80.
• the photodetectors 38 may be distributed in rows and in columns.
• the pitch p of the openings 86 is smaller than the pitch of the photodetectors 38 of the image sensor 80. In this case, several openings 86 may be located opposite a photodetector 38, as shown. diagrammatically in FIG. 5.
• the pitch p of the openings 86 is identical to the pitch of the photodetectors 38 of the image sensor 80.
• the angular filter 82 is then preferably aligned with the image sensor 80. so that each opening 86 is opposite a photodetector 38.
• the pitch p of the holes 64 is greater than the pitch of the photodetectors 38 of the image sensor 80. In this case, several photodetectors 38 may be located opposite an opening 86.
• the h / w ratio can be between 1 and 10.
• the pitch p can be between 10 ⁇ m and 60 ⁇ m, for example about 15 ⁇ m.
• the height h may be between 1 ⁇ m and 1 mm, preferably between 20 ⁇ m and 100 ⁇ m.
• the width w can be between 5 ⁇ m and 30 ⁇ m, for example about 10 ⁇ m.
• Figure 8 is a sectional view, partial and schematic, of a variant of the embodiment shown in Figure 6, in which the cross section of the openings 86 is not constant, the cross section decreasing as and as one moves away from the substrate 32. As a variant, the cross section may increase as one moves away from the substrate 32, successively comprising a decrease phase followed by an enlargement phase as it moves away of substrate 32, etc.
• Figure 9 is a sectional view, partial and schematic, of another embodiment of the angular filter 82.
• the angular filter 82 comprises the structure shown in Figures 6 and 7 and further comprises for each opening 86, a microlens 92 resting on the layer 84 and covering the opening 86.
• a tie layer 94 is arranged between the microlenses 92 and the substrate 32.
• Each microlens 92 allows, advantageously, to increase the collection of rays of the incident radiation whose incidence is less than a desired maximum angle of incidence but which would be blocked by the walls of the openings 86 in the absence of the microlens 92. Such an embodiment is particularly suitable for applications in which the light level is low.
• the material for filling the apertures 86 may be the same as the material composing the microlenses 92.
• the microlenses may be converging lenses each having a focal length f of between 1 ⁇ m and 100 ⁇ m, preferably between 1 ⁇ m and 50 ⁇ m.
• the pitch of the microlenses 92 can be the same as the pitch of the photodetectors 38 or smaller.
• the apertures 86 of the angular filter 82 essentially act as an optical microdiaphragm. between the microlenses 92 and the photodetectors 38 so that there is less constraint on the w / h aspect ratio of the openings 86 compared to the case where the microlenses 92 are not present.
• the maximum angle of incidence is determined by the width w of the openings 86 and the curvature of the microlenses 92.
• each microlens can be replaced by another type of optical element of micrometric size, in particular a Fresnel lens of micrometric size, a lens with a gradient of index of micrometric size or a diffraction grating of micrometric size.
• FIG. 10 is a side section of an embodiment of an image sensor 95.
• the image sensor 95 comprises all the elements of the image sensor 80 shown in FIG. 5, at the bottom. difference that the angular filter 82 is located in the stack 34.
• the angular filter 82 is located in an insulating layer 96 covering the layer 58.
• the height h of the openings 86 may be equal to or less than 1 The thickness of the insulating layer 96.
• the insulating layer 96 can fill the openings 86.
• the vias 60 which connect the electrodes 36 to conductive tracks 56, therefore also pass through the angular filter 82 and the insulating layer 96.
• the sensor d The images 95 is intended to be illuminated from the side of the substrate 32.
• FIG. 11 is a side section of an embodiment of an image sensor 100.
• the image sensor 100 comprises all the elements of the image sensor 80 shown in FIG. 5, at the bottom. difference that the angular filter 82 is located on the electrode 40, on the side of the electrode 40 opposite the photodetectors 38.
• the openings 86 can be filled with the adhesive material of the layer. adhesive 42.
• the image sensor 100 is intended to be illuminated from the side of the coating 44.
• the substrate 32 is made of a material at least partially transparent to the radiation picked up by the photodetectors 38.
• the substrate 32 can be a rigid substrate or a flexible substrate.
• the substrate 32 can have a single-layer structure or correspond to a stack of at least two layers.
• An example of a rigid substrate comprises a silicon, germanium or glass substrate.
• the substrate 32 is a flexible film.
• An example of a flexible substrate comprises a film made from PEN (polyethylene naphthalate), PET (polyethylene terephthalate), PI (polyimide), TAC (cellulose triacetate), COP (cycloolefin copolymer) or PEEK (polyetheretherketone).
• the substrate 32 can comprise an inorganic layer, for example of glass, covered with an organic layer, for example of PEN, PET, PI, TAC, COP.
• the thickness of the substrate 32 can be between 5 ⁇ m and 1000 ⁇ m.
• the substrate 32 may have a thickness of 10 ⁇ m to 500 ⁇ m, preferably between 20 ⁇ m and 300 ⁇ m, in particular of the order of 75 ⁇ m, and exhibit a flexible behavior, that is to say say that the substrate 32 can, under the action of an external force, deform, in particular bend, without breaking or tearing.
• the intermediate layer 33 can be a layer substantially impermeable to oxygen and to humidity in order to protect the organic layers of the detection matrix 30. It can be a layer or layers deposited by a thin film deposition process (ALD, acronym for Atomic Layer Deposition), for example an Al2O3 layer, of layers deposited by physical vapor deposition (PVD, acronym for Physical Vapor Deposition) or by chemical vapor deposition plasma assisted (PECVD, acronym for Plasma-Enhanced Chemical Vapor Deposition), by example in SiN or in Si0 2 -
• ALD Atomic Layer Deposition
• PVD physical vapor deposition
• PECVD chemical vapor deposition plasma assisted
• the intermediate layer 33 may have a monolayer structure or correspond to a stack of at least two layers, comprising, for example, organic layers and inorganic layers.
• the conductive tracks 50, 51, 56, the electrode 40 (when the image sensor is intended to be illuminated from the side of the substrate 32), and the electrode 36 and the via 60 (when the image sensor is intended to be illuminated from the side of the coating 44) can have a single-layer or multi-layer structure.
• Each insulating layer 52, 58, 96 of the stack 34 can be made of an inorganic material, for example of silicon oxide (SiCy) or of a silicon nitride (SiN), or an insulating organic layer, for example of organic resin.
• the material making up the electrodes 36, 40 is chosen from the group comprising:
• TCO Transparent Conductive Oxide
• ITO indium oxide doped with tin
• AZO oxides of zinc and aluminum
• GZO oxides of gallium and zinc
• WO3 nickel oxide
• NiO nickel oxide
• V2O5 vanadium oxide
• M0O3 molybdenum oxide
• metals or metal alloys for example silver (Ag), gold (Au), lead (Pb), palladium (Pd), copper (Cu), nickel (Ni), tungsten (W), molybdenum (Mo), aluminum (Al), or chromium (Cr) or alloys of magnesium and silver (MgAg);
• PEDOT PEDOT: PSS polymer, which is a mixture of poly (3, 4) -ethylenedioxythiophene and sodium polystyrene sulfonate, or a polyaniline; and
• the electrode 40 and the coating 44 are at least partially transparent to the electromagnetic radiation picked up by the photodiodes 38.
• the electrode 40 is for example made of TCO, or of doped polymer, for example of PEDOT: PSS.
• the electrodes 36 and the substrate 32 can then be opaque to the electromagnetic radiation picked up by the photodiodes 38.
• the electrodes 36 and the substrate 32 are a material at least partially transparent to the radiation. electromagnetic sensed by the photodiodes 38.
• the electrodes 36 are for example made of TCO.
• the electrode 40 can then be opaque to the electromagnetic radiation picked up by the photodiodes 38.
• the layer of adhesive material 42 When the image sensor is illuminated from the side of the coating 44, the layer of adhesive material 42 is transparent or partially transparent to visible light.
• the layer of adhesive material 42 is preferably substantially airtight and watertight.
• the material making up the layer of adhesive material 42 is chosen from the group comprising a polyepoxide or a polyacrylate.
• the material making up the layer of adhesive material 42 may be chosen from the group comprising epoxy resins containing bisphenol A, in particular diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol A and tetrabromobisphenol A, epoxy resins bisphenol F, epoxy novolac resins, in particular epoxy-phenol-novolac (EPN) and epoxy-cresol-novolac (ECN) resins, aliphatic epoxy resins, in particular epoxy resins containing glycidil groups and cycloaliphatic epoxides, epoxy glycidylamine resins, in particular the glycidyl ethers of methylene dianiline (TGMDA), and a mixture of at least two of these compounds.
• DGEBA diglycidyl ether of bisphenol A
• EPN epoxy-phenol-novolac
• ECN epoxy-cresol-novolac
• aliphatic epoxy resins in particular epoxy resins containing glycid
• the material composing the adhesive material layer 42 can be made from monomers comprising acrylic acid, methyl methacrylate, acrylonitrile, methacrylates, methyl acrylate, ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate, trimethylolpropane triacrylate (TMPTA) and derivatives of these products.
• monomers comprising acrylic acid, methyl methacrylate, acrylonitrile, methacrylates, methyl acrylate, ethyl acrylate, 2-chloroethyl vinyl ether, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate, trimethylolpropane triacrylate (TMPTA) and derivatives of these products.
• TMPTA trimethylolpropane tri
• the thickness of the layer of adhesive material 42 is between 1 ⁇ m and 50 ⁇ m, preferably between 5 ⁇ m and 40 ⁇ m, in particular of the order of 15 ym.
• the coating 44 is a flexible film.
• An example of a flexible film comprises a film made of PEN (polyethylene naphthalate), PET (polyethylene terephthalate), PI (polyimide), TAC (cellulose triacetate), COP (cycloolefin copolymer) or PEEK (polyetheretherketone).
• the thickness of the coating 44 can be between 5 ⁇ m and 1000 ⁇ m.
• the coating 44 may comprise at least one substantially impermeable layer. oxygen and humidity in order to protect the organic layers of the detection matrix 30.
• the coating 44 can comprise at least one layer of SiN, for example deposited by PECVD and / or a layer of aluminum oxide ( AI 2 O 3) , for example deposited by ALD.
• the layer 37 in which the photodiodes 38 are formed can comprise small molecules, oligomers or polymers. They can be organic or inorganic materials. Layer 37 may comprise an ambipolar semiconductor material, or a mixture of an N-type semiconductor material and a P-type semiconductor material, for example in the form of superimposed layers or an intimate mixture at the nanoscale of so as to form a heterojunction in volume.
• the thickness of the layer 37 may be between 50 nm and 2 ⁇ m, for example of the order of 500 nm.
• P-type semiconductor polymers suitable for making the layer 37 are poly (3-hexylthiophene) (P3HT), poly [N-9 ′ -heptadecanyl-2, 7-carbazole-alt-5 , 5- (4, 7-di-2-thienyl-2 ', l', 3 '- benzothiadiazole)] (PCDTBT), poly [(4, 8-bis- (2-ethylhexyloxy) -benzo [1, 2-b; 4, 5-b '] dithiophene) -2, 6-diyl- alt- (4- (2-ethylhexanoyl) -thieno [3, 4-b] thiophene)) -2, 6-diyl] ( PBDTTT-C), poly [2-methoxy-5- (2-ethyl-hexyloxy) -1, 4-phenylene-vinylene] (MEH-PPV) or poly [2, 6- (4, 4-bis- (2-ethyl)
• N-type semiconductor materials suitable for making layer 37 are fullerenes, in particular C60, [6, 6] -phenyl-C 6i- methylbutanoate ([60] PCBM), [6, 6] -phenyl-C 7i methyl butanoate
• each interface layer can be between 0.1 nm and 1 ⁇ m.
• One of the interface layers can be made of cesium carbonate (CsCCy), of metal oxide, in particular of zinc oxide (ZnO), or of a mixture of at least two of these compounds.
• One of the interface layers may comprise a self-assembled monomolecular layer or a polymer, for example of (polyethyleneimine, ethoxylated polyethyleneimine, poly [(9,9- bis (3 '- (N, N-dimethylamino) propyl) - 2, 7-fluorene) -alt-2, 7-
• the other interface layer can be made of copper oxide (CuO), nickel oxide (NiO), vanadium oxide (V2O5), magnesium oxide (MgO), tungsten oxide (WO 3) or in a mixture of at least two of these compounds.
• the active regions 54 can be in polycrystalline silicon, in particular polycrystalline silicon deposited at low temperature (LTPS, acronym for Low Temperature Polycrystalline Silicon), in amorphous silicon (aSi), in zinc-gallium-indium oxide (IGZO). ), in polymer, or include small molecules used in a known manner for the production of organic thin film transistors (OTFT, acronym for Organic Thin Film Transistor).
• LTPS Low Temperature Polycrystalline Silicon
• aSi amorphous silicon
• IGZO zinc-gallium-indium oxide
• OTFT organic thin film transistors
• the layer 84 can be entirely made of an absorbent material at least for the wavelengths to be angularly filtered.
• Layer 84 may be a colored resin, for example a colored or black SU-8 resin.
• the layer 84 can be made of a black resin which absorbs in the visible and near infrared ranges.
• the openings 86 may be filled with air or filled with a material at least partially transparent to the radiation detected by the photodetectors 38, for example. polydimethylsiloxane (PDMS).
• PDMS polydimethylsiloxane
• the openings 86 can be filled with a partially absorbent material in order to chromatically filter the rays filtered angularly by the angular filter 82.
• the angular filter 82 can then also play the role of a color filter. This makes it possible to reduce the thickness of the system compared to the case where a color filter distinct from the angular filter 82 would be present.
• the partially absorbent filler material can be a colored resin or a colored plastic material such as PDMS.
• the material for filling the openings 86 can be adapted in order to have an adaptation of the refractive index with the layers in contact with the angular filter 82, or else to stiffen the structure and improve the mechanical strength of the angular filter 82.
• the microlenses 92 can be made of silica, of poly (methyl methacrylate) (PMMA), of a positive photosensitive resin, of PET, of PEN, of COP, of a mixture of polydimethylsiloxane (PDMS) and silicone, or epoxy resin.
• PMMA poly (methyl methacrylate)
• PDMS polydimethylsiloxane
• the microlenses 14 can be formed by creeping blocks of a photosensitive resin.
• the microlenses 14 can further be formed by molding on a layer of PET, PEN, COP, PDMS / silicone or epoxy resin.
• the tie layer 94 can be obtained from an optically transparent adhesive (OCA, acronym for Optically Clear Adhesive), in particular an optically transparent liquid adhesive (LOCA, acronym for Liquid
• the layer 94 is of a material having a low refractive index, lower than that of the material of the microlenses 92.
• the layer 94 may be of a filling material which is a transparent non-adhesive material.
• the layer 94 corresponds to a film against which the array of microlenses 92 is applied, for example an OCA film.
• the contact zone between the layer 94 and the microlenses 92 can be reduced, for example limited to the tops of the microlenses.
• Layer 94 can then be composed of a material having a higher refractive index than in the case where layer 94 matches the shape of microlenses 96.
• the process for forming at least some layers of the image sensor may correspond to a so-called additive process, for example by direct printing of the material composing the organic layers at the desired locations, in particular in the form of sol -gel, for example by inkjet printing, heliography, screen printing, flexography, spray coating (in English spray coating) or depositing drops (in English drop-casting).
• the process for forming the layers of the image sensor may correspond to a so-called subtractive process, in which the material making up the organic layers is deposited on the entire structure and in which the unused portions are then removed. , for example by photolithography or laser ablation.
• the layers may in particular be processes of the spin coating, spray coating, heliography, slot-die coating, blade coating, flexography or screen printing type.
• the metal is, for example, deposited by evaporation or by cathodic sputtering on the whole of the support and the metallic layers are delimited by etching.
• at least some of the layers of the image sensor can be produced by printing techniques.
• the materials of these layers described above can be deposited in liquid form, for example in the form of conductive and semiconductor inks using inkjet printers.
• the term “materials in liquid form” is understood here also to mean gel materials which can be deposited by printing techniques.
• Annealing steps are optionally provided between the depositions of the different layers, but the annealing temperatures may not exceed 150 ° C., and the deposition and any annealing may be carried out at atmospheric pressure.
• Figures 12 to 16 are sectional views of the structures obtained in successive steps of an embodiment of a method of manufacturing the image sensor 80 shown in Figure 5, comprising the following successive steps:
• the substrate 32 comprising for example a stack of two layers 102, 104 (FIG. 12);
• the final steps of the method include in particular the application of the coating 44 and the layer 42 of adhesive material.
• An embodiment of a method of manufacturing the image sensor 95 shown in Figure 10 comprises the steps described above in relation to Figures 12 to 18 with the difference that steps b), c) and d) are carried out after step f).
• An advantage of the methods for manufacturing image sensors 80 and 95 is that the opaque layer 84 of the angular filter 82 is not deposited in contact with the layer 37, the solvent used for the deposition of the opaque layer 84 being able to degrade the film. layer 37.
• An embodiment of a method of manufacturing the image sensor 100 shown in Figure 11 comprises the steps described above in relation to Figures 12 to 18 with the difference that steps b), c) and d) are carried out after step g) and before the application of the coating 44 and of the layer 42 of adhesive material.
• An advantage of the methods for manufacturing image sensors 80, 95 and 100 is that the opaque layer 84 of the angular filter 82 is not deposited in contact with the coating 44, the steps of forming the openings 86 being able to degrade the coating 44.

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• Transforming Light Signals Into Electric Signals (AREA)
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• 2019
  • 2019-03-22 FR FR1902965A patent/FR3094140B1/fr active Active
• 2020
  • 2020-02-20 JP JP2021557020A patent/JP2022528629A/ja active Pending
  • 2020-02-20 WO PCT/FR2020/050317 patent/WO2020193889A1/fr active Application Filing
  • 2020-02-20 EP EP20710258.3A patent/EP3942613A1/de not_active Withdrawn
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