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    • 专利摘要:
    The invention relates to a method for producing an optoelectronic device (1) comprising a matrix of light-emitting diodes (4) and a plurality of photoluminescent pads (61, 62, 63 ...) each located facing each other. at least a portion of said light-emitting diodes (4), comprising the following steps: - forming said plurality of photoluminescent pads (61, 62, 63 ...) by photolithography of at least one photoresist (51, 52, 53 ...) containing photoluminescent particles previously deposited on a support surface (3; 3 '); - forming reflective walls (101, 102, 103 ...) covering side flanks (81, 82, 83 ...) of said photoluminescent pads (61, 62, 63 ..), by depositing at least a portion thin layer (91, 92, 93 ...) on the lateral flanks (81, 82, 83 ...).
    公开号:FR3061358A1
    申请号:FR1663410
    申请日:2016-12-27
    公开日:2018-06-29
    发明作者:Eric Pourquier；Philippe Gilet；Chang YING-LAN
    申请人:Aledia；
    IPC主号:
    专利说明:

    Holder (s):
    Applicant (s): ALEDIA Simplified joint stock company - FR.
    Inventor (s): POURQUIER ERIC, VEST PHILIPPE efYING-LAN CHANG.
    ALEDIA Simplified joint-stock company.
    ® Agent (s): INNOVATION COMPETENCE GROUP.
    FR 3 061 358 - A1 ® PROCESS FOR MANUFACTURING A PHOTOLUMINESCENT DEVICE OF PHOTORESIN.
    @) The invention relates to a method for producing an optoelectronic device (1) comprising a matrix of light-emitting diodes (4) and a plurality of photoluminescent pads (6 ^ 6 2 , 6 3 ...) each located in screw -with respect to at least part of said light-emitting diodes (4), comprising the following steps:
    - Formation of said plurality of photoluminescent pads (6 3 , 6 2 , 6 3 ...) by photolithography of at least one photosensitive resin (5 υ 5 2 , 5 3 ...) containing photoluminescent particles previously deposited on a support surface (3; 3 d;
    - formation of reflective walls (10 1s 10 2 , 10 3 ...) covering lateral flanks (8 υ 8 2 , 8 3 ...) of said photoluminescent studs (61, 6 2 , 6 3 ..), by deposition at least a portion of thin layer (9d, 9 2 , 9 3 ...) on the lateral flanks (81.8 2 , 8 3 ...).
    OPTOELECTRONICS WITH PLOTS
    NOT dS 7 2 io t 1 i! 6, "J- 'b- s 26, f(( 14
    METHOD FOR MANUFACTURING AN OPTOELECTRONIC DEVICE COMPRISING PHOTOLUMINESCENT PLATES OF PHOTORESIN
    TECHNICAL FIELD [001] The field of the invention is that of methods of manufacturing optoelectronic devices comprising light-emitting diodes associated with photoluminescent pads. The invention finds application in particular in display screens or image projection systems.
    STATE OF THE PRIOR ART [002] There are optoelectronic devices comprising a matrix of light-emitting diodes having an emitting surface, this emitting surface being coated at least in part by photoluminescent studs. Such optoelectronic devices can form display screens or image projection systems comprising a matrix of bright pixels of different colors.
    Light-emitting diodes can be formed from a semiconductor material comprising elements from column III and column V of the periodic table, such as a III-V compound, in particular gallium nitride (GaN), indium and gallium nitride (InGaN) or aluminum and gallium nitride (AlGaN). They are arranged so as to form a matrix of light-emitting diodes having an emitting surface through which is transmitted the light radiation emitted by the light-emitting diodes.
    In the case of a display screen or an image projection system, the optoelectronic device can thus comprise a matrix of light pixels, each light pixel comprising one or more light-emitting diodes. In order to obtain luminous pixels adapted to emit lights of different colors, for example blue, green or red, the light-emitting diodes can be adapted to emit blue light, and certain luminous pixels can comprise photoluminescent studs adapted to absorb at least in part the blue light emitted by the light-emitting diodes, and to emit in response a green or red light. The photoluminescent pads are usually formed of a binding matrix comprising particles of a photoluminescent material such as yttrium aluminum garnet (YAG, for Yttrium Aluminum Carnet, activated by the cerium ion YAG: Ce .
    In general, there is a need for a method of manufacturing an optoelectronic device making it possible to increase the resolution while optimizing the contrast.
    PRESENTATION OF THE INVENTION The aim of the invention is to propose a method for manufacturing an optoelectronic device with light emitting diodes, comprising photoluminescent pads, which makes it possible to obtain optoelectronic devices with high resolution and high contrast.
    For this, the object of the invention is a method of manufacturing an optoelectronic device comprising an array of light emitting diodes and a plurality of photoluminescent pads each located opposite at least a portion of said light emitting diodes, comprising the following steps:
    - Formation of said plurality of photoluminescent pads by photolithography of at least one photosensitive resin containing photoluminescent particles previously deposited on a support surface;
    - formation of reflective walls covering the lateral flanks of said photoluminescent pads, by depositing at least a portion of thin layer on the lateral flanks.
    Some preferred but non-limiting aspects of this process are as follows.
    The step of forming the reflective walls may include a conformal deposit of at least one thin layer of a reflective material so as to cover the photoluminescent pads, then localized etching of the deposited thin layer, so as to make free a so-called upper surface of the photoluminescent pads opposite to said support surface.
    The steps for forming the plurality of photoluminescent pads, and for forming the reflective walls may include the following steps:
    - Formation of a plurality of first photoluminescent pads, by photolithography of a first photosensitive resin containing first photoluminescent particles previously deposited on said support surface;
    - Formation of first reflective walls covering the lateral flanks of said first photoluminescent pads by conformal deposition of a thin reflective layer on the first photoluminescent pads, then localized etching so as to make free an upper surface of the first photoluminescent pads;
    - Formation of a plurality of second photoluminescent pads, by photolithography of a second photosensitive resin containing second photoluminescent particles previously deposited on said support surface, the second photoluminescent particles being different from the first photoluminescent particles.
    The method may comprise, following the step of forming the plurality of second photoluminescent pads, a step of forming second reflective walls covering the lateral flanks of said second photoluminescent pads by conformal deposition of a thin reflective layer on the first and second photoluminescent pads, then localized etching so as to free the upper surface of the first and second photoluminescent pads.
    Each second photoluminescent pad can be in contact with at least one first reflective wall.
    Each first reflective wall may have a thickness between lOnm and 500nm.
    The step of forming the plurality of photoluminescent pads may include at least one formation of several first photoluminescent pads containing first photoluminescent particles followed by the formation of several second photoluminescent pads containing second photoluminescent particles different from the first photoluminescent particles , the step of forming the reflective walls being carried out after the formations of at least the first and second photoluminescent pads.
    The reflective walls can be formed by electrochemical deposition.
    The average size of the photoluminescent particles can be less than or equal to 500nm.
    The photoluminescent particles can be quantum dots, and can have an average size less than or equal to 50nm.
    The photoluminescent pads can have an average height less than or equal to 30pm.
    The light emitting diodes can be elongated three-dimensional elements extending longitudinally substantially orthogonal to a main plane of a support layer.
    The light-emitting diodes may be located inside the photosensitive resin pads, at least part of the pads of which are photoluminescent pads comprising photoluminescent particles.
    The photoluminescent pads can rest on a support surface, called the transmission surface, formed by a spacer layer covering the light-emitting diodes.
    The invention also relates to an optoelectronic device, comprising:
    - a matrix of light-emitting diodes resting on a support layer;
    - A plurality of first photoluminescent pads, each located opposite at least a portion of said light emitting diodes, each formed of a first photosensitive resin comprising first photoluminescent particles, having lateral flanks covered by a layer portion thin deposited forming a first reflecting wall;
    - A plurality of second photoluminescent pads, each located opposite at least a portion of said light emitting diodes, each formed of a second photosensitive resin comprising second photoluminescent particles different from the first photoluminescent particles, having lateral flanks covered by a portion of deposited thin layer forming a second reflecting wall.
    Each second photoluminescent pad can be in contact with a first reflecting wall.
    The light emitting diodes may have an elongated three-dimensional structure along a longitudinal axis substantially orthogonal to the support layer.
    The light emitting diodes can be located inside the photoluminescent pads.
    Light emitting diodes can have a mesa structure.
    BRIEF DESCRIPTION OF THE DRAWINGS Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of nonlimiting example, and made with reference to the accompanying drawings in which:
    Figures IA to 1F are schematic and partial views, in cross section, of different stages of a manufacturing process according to a first embodiment, in which the photoluminescent pads are produced by photolithography of different photosensitive resins containing photoluminescent particles;
    FIGS. 2A to 2H are schematic and partial views, in cross section, of different stages of a manufacturing process according to a second embodiment, in which the resolution of the pixels can be increased compared to that obtained in the context of method according to the first embodiment;
    FIG. 3A is a schematic and partial top view of a variant of the manufacturing method according to the second embodiment, in which the lateral flanks of each second photoluminescent stud are in contact with first reflecting walls, in the case here of 'an example of a Bayer matrix; and FIG. 3B is a schematic and partial view, in cross section, of an optoelectronic device obtained from another variant of the manufacturing method according to the second embodiment, in which the reflecting walls are inclined;
    FIG. 4A is a schematic and partial view, in cross section, of an optoelectronic device obtained by the manufacturing method according to the second embodiment, in which the light-emitting diodes are of the wired type, FIG. 4B illustrates in detail a example of wired light-emitting diodes in core / shell configuration and FIG. 4C illustrates another example of wired light-emitting diodes in axial configuration;
    Figure 5 is a schematic and partial view, in cross section, of an optoelectronic device obtained by the manufacturing method according to the second embodiment, in which the light emitting diodes are of the mesa type;
    FIGS. 6A to 61 are schematic and partial views, in cross section, of different stages of a manufacturing process according to a third embodiment, in which the light-emitting diodes are located inside the photosensitive resin pads; and FIG. 7 is a schematic and partial view, in cross section, of an optoelectronic device obtained by a variant of the method according to the second embodiment, in which the reflective walls of two adjacent photoluminescent pads are in contact with one the other.
    DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS In the figures and in the following description, the same references represent the same or similar elements. In addition, the different elements are not shown to scale so as to favor the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with one another. Unless otherwise indicated, the terms "substantially", "approximately", "in the order of" mean to the nearest 10%.
    The invention relates to a method of manufacturing an optoelectronic device with light emitting diodes comprising photoluminescent pads. More specifically, the optoelectronic device comprises a matrix of light emitting diodes distributed in different light pixels, the photoluminescent pads each being located opposite at least a portion of the light emitting diodes. By located opposite, it is meant that the photoluminescent pads are located opposite the light-emitting diodes and can be spaced or in contact with the latter.
    According to an embodiment detailed below, the photoluminescent pads can be located opposite the light-emitting diodes and spaced from the latter by a spacer layer. In other words, the photoluminescent pads are not in contact with the light-emitting diodes. They can rest on a support surface called optical transmission of the spacer layer. The transmission surface is the surface of the spacer layer through which the so-called excitation light radiation emitted by the light-emitting diodes is transmitted towards the photoluminescent pads. As a variant, the transmission surface may be a surface of a transparent plate on which the photoluminescent pads have been previously produced, the transparent plate then being attached and fixed to the matrix of light-emitting diodes, for example on the spacer layer.
    According to another embodiment detailed below, the photoluminescent pads can be located vis-à-vis the light emitting diodes and in contact with the latter. In other words, at the level of a light pixel, the light-emitting diodes are located inside and in contact with the corresponding photoluminescent pad. The photoluminescent pad then surrounds each of the corresponding light-emitting diodes. The light-emitting diodes and the photoluminescent pads rest on the same support surface of a so-called support layer. This embodiment relates more particularly to light-emitting diodes of the wired type.
    The photoluminescent pads are adapted to convert at least partly excitation light radiation emitted by the light emitting diodes into light radiation called luminescence of a different wavelength. Each photoluminescent pad has a binding matrix transparent to excitation and luminescence light radiation in which photoluminescent particles are dispersed. The photoluminescent pads rest on a support surface, for example a surface of a support layer on which the light-emitting diodes also rest or a surface of a transparent spacer layer which covers the light-emitting diodes, or even a surface of a transparent plate. reported. Each photoluminescent stud has a so-called upper surface opposite the support surface, intended to transmit luminescent light radiation, and lateral flanks which extend from the upper surface to the support surface and thus delimit the stud laterally.
    The binding matrix of the photoluminescent pads is here a photosensitive resin, or photoresist. By photosensitive resin is meant here a material whose solubility in a so-called developer solvent varies under the effect of a determined light radiation which is applied to it, here in the context of a photolithography step. It can be chosen from positive or negative resins, these categories of photosensitive resin being known to a person skilled in the art. Each photoluminescent pad is formed of a photosensitive resin, which can be identical or different from one pad to another, comprising the photoluminescent particles.
    The photosensitive resin is transparent and optically inert to light radiation emitted by light emitting diodes and by photoluminescent particles. Thus, the resin transmits at least 50% of the light emitted by light-emitting diodes and that emitted by photoluminescent particles, and preferably at least 80%, and it does not emit light in response to an absorption of this light. . It can be chosen from silicone, or polysiloxane, such as polydimethylsiloxane (PDMS), SU-8 resin, thermoplastic polymers such as polymethyl methacrylate (PMMA), polyimide, or from other photosensitive resins which may be suitable. .
    The photoluminescent particles are elements of at least one photoluminescent material suitable for converting at least part of the excitation light into luminescence light of longer wavelength. By way of illustration, they can be adapted to absorb blue light, that is to say one whose wavelength is between 440nm and 490nm approximately, and to emit in the green, that is to say at a wavelength between 495nm and 560nm approximately, or even in the red, that is to say at a wavelength between 600nm and 650nm. By wavelength is meant here the wavelength for which the emission spectrum has an intensity peak. By way of illustration only, the light-emitting diodes can have an emission spectrum whose intensity peak is between 380nm and 490nm.
    The photoluminescent particles are distinct from each other, and have a shape which can be any, for example spherical, angular, flattened, elongated, or any other shape. The size of a particle here is the smallest dimension of the particle, and the average size is the arithmetic mean of the particle sizes. The photoluminescent particles may have an average size of between 0.2 nm and 100 nm, for example less than 500 nm, for example less than 100 nm, and preferably less than 50 nm.
    Preferably, the photoluminescent particles are in the form of quantum dots (quantum dots, in English), that is to say in the form of semiconductor nanocrystals whose quantum confinement is substantially three-dimensional. The average size of the quantum dots can then be between 0.2 nm and 50 nm, for example between lnm and 30 nm. The quantum dots can be formed from at least one semiconductor compound, which can be chosen from cadmium selenide (CdSe), indium phosphorus (InP), gallium and indium phosphorus (InGaP), sulfide cadmium (CdS), zinc sulfide (ZnS), cadmium oxide (CdO) or zinc (ZnO), zinc and cadmium selenide (CdZnSe), zinc selenide (ZnSe) for example with copper or manganese, graphene or among other semiconductor materials which may be suitable. The quantum dots can also have a core / shell type structure, such as CdSe / ZnS, CdSe / CdS, CdSe / CdS / ZnS, PbSe / PbS, CdTe / CdSe, CdSe / ZnTe, InP / ZnS or other. The size and / or composition of the photoluminescent particles are chosen according to the desired luminescence wavelength.
    The photoluminescent pads are in the form of a block of photosensitive resin, the thickness of which is defined as being the largest dimension along an axis orthogonal to the surface on which they rest. The cross section of the studs, in a plane parallel to said surface on which they rest, can have different shapes, for example a circular, oval, polygonal shape, for example triangular, square, rectangular, even hexagonal. The width of a stud is defined here as being a transverse dimension of the stud at the level of a cross section. The local width is the width of the stud at a given height thereof. The average width is the average, for example arithmetic, of the local widths according to the thickness dimension of the stud.
    The thickness of a photoluminescent pad can be between 0, lpm and 50pm, and preferably between lpm and 30pm, for example equal to about 20pm. The width of a photoluminescent pad depends on that of a light pixel and therefore on the application of the optoelectronic device. It can be between 0.5pm and 100pm, for example between lpm and 20pm, for example equal to around 10pm in the case of a display screen or a projection system. Furthermore, the mass fraction of photoluminescent particles in the photosensitive resin can be between 10% and 70%, and preferably between 25% and 60%, for example equal to 30%. It is adapted in particular according to the thickness of the photoluminescent pad so as to allow the exposure of the photosensitive resin over its entire thickness during a photolithography step, as well as the desired light conversion rate.
    Figures IA to 1F illustrate a method of manufacturing an optoelectronic device with light emitting diodes according to a first embodiment.
    We define here and for the rest of the description a direct three-dimensional reference (Χ, Υ, Ζ), where the plane (X, Y) is substantially parallel to the main plane of an optoelectronic chip 2, and where the Z axis is oriented in a direction orthogonal to the XY plane.
    FIG. 1A illustrates the supply of a matrix of light-emitting diodes, having a transmission surface 3, followed by a deposit of a first photosensitive resin 5i comprising first photoluminescent particles.
    The matrix of light emitting diodes (not shown) is formed here in an optoelectronic chip 2, and defines a matrix of light pixels P. A surface of the optoelectronic chip 2 forms the transmission surface 3 of the matrix of light emitting diodes. The transmission surface 3 is here substantially flat, with the possible presence of surface microstructures making it possible to improve the extraction of light.
    The light-emitting diodes are here produced based on the same semiconductor compound, for example based on a III-Vtel compound as GaN. By based on, it is meant that the light-emitting diodes mainly comprise said semiconductor compound. As detailed below, each light-emitting diode comprises a stack of first and second doped semiconductor portions, between which is an active area. The active area is the region of a light emitting diode where light radiation is emitted. The light-emitting diodes can have different structures, such as wire or mesa structures, examples of which are respectively described below with reference to FIGS. 4B and 4C, and to FIG. 5. In this example, the light-emitting diodes are adapted to emit a blue light, that is to say a light whose emission spectrum has a peak of intensity at a wavelength between 440nm and 490nm approximately.
    A first photosensitive resin 5i is deposited on the light-emitting diodes, here without being in contact with the latter. More specifically, it is deposited on a support surface, here the transmission surface 3 of the optoelectronic chip 2, so as to be located opposite the light-emitting diodes. The first photosensitive resin 5i comprises first photoluminescent particles, here quantum dots, adapted to convert at least partly the blue light emitted by the light-emitting diodes into red, green or other light, for example here in red light. The photosensitive resin 5i can be deposited on the entire transmission surface 3. It can be deposited by a conventional technique known to a person skilled in the art, for example by spinning, spray-type spraying, heliography, serigraphy or other.
    The photosensitive resin 51 has a substantially constant local thickness over the entire extent of the transmission surface 3, and has an average thickness preferably between 0, lpm and 50pm, preferably between lpm and 40pm, for example equal to about 20 pm.
    In this example, it comprises photoluminescent particles, here quantum dots, adapted to at least partially convert the blue light emitted by the light-emitting diodes into red light. For example, quantum dots formed from CdSe semiconductor nanocrystals whose average size is between 3nm and 12nm, for example equal to about 3.6nm, are suitable for converting blue light into red light. The first photosensitive resin 5i has a mass fraction of quantum dots which can be between 10% and 70%, and preferably between 25% and 60%, for example equal to around 30%.
    Figure IB illustrates a step of forming first photoluminescent pads 6i by photolithography of the first photosensitive resin 5i. The first pads 6i are distinct from each other and are positioned on the transmission surface 3 at the level of pixels Pr intended to emit red light.
    In this example, the first photoluminescent pads 6i have dimensions which are substantially identical to each other. They are formed here from a block of first photosensitive resin 5i with a cross section in the substantially square or rectangular XY plane. Each first photoluminescent pad 6i then comprises a so-called upper surface 7i, opposite to the transmission surface 3, and lateral flanks 81 which extend from the upper surface 7i to the transmission surface 3. In other words, the light-emitting diodes rest on a support layer (not shown) of the optoelectronic chip, and the upper surface of the photoluminescent pads is the surface of the pads opposite the support layer along the Z axis. The thickness of the first pads 6i is here substantially equal at 20pm and the average width is substantially equal to the size of a pixel, for example here equal to approximately 10pm.
    Figure IC illustrates a step of depositing a second photosensitive resin 5 2 on the transmission surface 3. It can be deposited by one of the techniques mentioned above, so as to cover the transmission surface 3 uncoated by the first photoluminescent studs 6i. It thus comes into contact with the lateral flanks 8i of the first photoluminescent pads 6i. In this example, it has a thickness substantially equal to that of the first photoluminescent studs 61 but may have a different thickness, for example greater.
    In this example, the second photosensitive resin 5 2 comprises second photoluminescent particles, here quantum dots, adapted to convert at least partially the blue light emitted by the light-emitting diodes into a light different from that emitted by the first particles photoluminescent, for example here in green light. By way of example, quantum dots formed from CdSe semiconductor nanocrystals whose average size is approximately 1.3 nm are suitable for converting blue light into green light. The second photosensitive resin 5 2 may have a mass fraction of quantum dots identical to or different from that of the first photosensitive resin 5i. While the second photoluminescent particles are different from the first photoluminescent particles, the binder matrix forming the second photosensitive resin 5 2 can be identical to that forming the first photosensitive resin 5i.
    Figure ID illustrates a step of forming second photoluminescent pads 6 2 by photolithography of the second photosensitive resin 5 2 . The second pads 6 2 are distinct from each other and are also distinct from the first pads 61, in the sense that they are not in contact with each other. They are positioned on the transmission surface 3 at the level of pixels Pg intended to emit green light.
    The second photoluminescent pads 6 2 may have identical or different dimensions from a second pad 6 2 to the other, and identical or different from those of the first pads 6i. In this example, the various studs 6i, 6 2 have dimensions which are substantially identical to one another. The second photoluminescent pads 6 2 are thus formed from a block of second photosensitive resin 5 2 with a straight section that is substantially square or rectangular in the XY plane. As for the first pads, each second photoluminescent pad 6 2 has a so-called upper surface 7 2 , opposite the transmission surface 3, and lateral flanks 8 2 which extend from the upper surface 7 2 to the transmission surface 3.
    The minimum distance, in the XY plane, separating each photoluminescent stud 6i, 6 2 from the neighboring studs 61, 6 2 is adapted to allow the formation of reflective walls 101, 10 2 covering the lateral flanks 81, 8 2 of the studs photoluminescent 61, 6 2 . This distance can thus be of the order of a few hundred nanometers to a few microns, or even more.
    In this example, the transmission surface 3 includes areas not coated with photoluminescent pads 6i, 6 2 , located opposite one or more light emitting diodes, thus defining light pixels Pb intended to emit light blue. These pixels Pb may have a size substantially equal to those of the light pixels Pg, Pr comprising photoluminescent pads 61, 6 2 . As a variant, the zones intended to form blue pixels may include photoluminescent studs whose photoluminescent particles are adapted to emit blue light of wavelength different from that of the blue light emitted by the diodes. For example, the diodes can emit at a wavelength of about 450nm and the photoluminescent particles can emit at a wavelength of about 480nm.
    FIG. 1E illustrates a step of conformal deposition of a thin layer 9 in at least one reflective material, for example in at least one metallic material. The thin layer 9 can thus be deposited by chemical vapor deposition (Chemical Vapor Deposition, in English), for example by atomic thin layer deposition (Atomic Layer Deposition, in English), or even by physical vapor deposition (Physical Vapor Deposition, in English), for example by electron beam, sputtering, or the like. By conformal deposition is meant the deposition of a thin layer on the photoluminescent pads 6 so that it extends locally substantially parallel to the surface it covers. The conformally deposited thin layer has a substantially homogeneous thickness. The local thickness may however vary between a minimum value at the level for example of a surface substantially orthogonal to the XY plane and a maximum value at the level of for example a surface substantially parallel to the XY plane. By way of illustration only, for a conformal deposition of a thin layer of 200 nm, the thickness of the layer can vary between a value of 100 nm at the level of the lateral flanks 8 of the pads 6 and a value of 200 nm at the level of the surface of transmission 3 and upper surfaces 7 of the studs 6.
    The thin layer 9 can be formed from the same reflective material or from a plurality of different materials deposited on top of each other. The reflective materials can be chosen from aluminum, silver, platinum, or any other suitable material. The thin layer 9 has a substantially uniform average thickness, which can be between 10 nm and 500 nm, and preferably between 50 nm and 300 nm, for example equal to approximately 100 nm at the level of the lateral flanks 8 of the pads 6.
    The thin layer 9 covers the various photoluminescent pads 61, 62 as well as the transmission surface 3 not coated by the pads 61, 62. Thus, it continuously covers the lateral flanks 81, 82 and the upper surfaces 7i, 72 of first and second photoluminescent pads 61, 62, as well as the transmission surface 3 located both between two adjacent light pixels comprising photoluminescent blocks, ie here green pixels Pg and red Pr, at the level of light pixels not comprising a pad photoluminescent, ie here blue pixels Pb [0059] FIG. 1F illustrates a step of forming reflecting walls 101, IO2 covering the lateral flanks 81, 82 of the photoluminescent pads 61, 62, by localized etching of the thin layer 9.
    Thus, the parts of the reflective thin layer 9 not located in contact with the lateral flanks 81, 82 of the photoluminescent pads 61, 62 are etched. This removes the parts of the thin layer 9 which cover the upper surfaces 7i, 72 photoluminescent pads 61, 62, and those which cover the areas of the transmission surface 3 defining the blue pixels P B are deleted. Thus, the upper surfaces 7i, 72 are made free, as well as the transmission surface 3 covered by the thin layer 9. By making free, it is meant that the surfaces are not covered by a layer. The parts of the thin layer 9 located on the transmission surface 3 between two adjacent light pixels Pg, Pr comprising photoluminescent blocks are also removed. Thus, the lateral flanks 8 of the studs 6 are covered by the reflective walls 10. In other words, the reflective walls 10 rest on the lateral flanks, covering them continuously by being in contact with them.
    This etching step can be carried out by dry etching, for example by plasma etching (RIE, ICP ...). Since the dry etching is highly anisotropic, only the parts of the thin reflective layer 9 remain covering the lateral flanks 81, 82 of the photoluminescent pads 61, 62, thus forming reflective walls 101, IO2 which surround the photoluminescent pads 61, 62 in a plane parallel to the XY plane.
    The layer of the transmission surface 3 can provide a stop function for the dry etching of the metal, thereby preserving the integrity of the light emitting diodes. It can thus be a face of a planarization layer of organic or mineral material, or even a passivation layer of a dielectric material, for example of silicon oxide (for example S1O2), of silicon nitride (for example S13N4), or in silicon oxynitride (SiON).
    Thus, the manufacturing method according to this first embodiment makes it possible to obtain an optoelectronic device having a high resolution as well as a high contrast. Indeed, by using a photosensitive resin containing photoluminescent particles and advantageously quantum dots, it is possible to form the photoluminescent pads directly by photolithography. It is thus possible to obtain a matrix of high resolution photoluminescent plots, avoiding the use of alternative techniques such as the localized deposition of drops containing photoluminescent particles. Such techniques have drawbacks notably linked to the control of the size of the drops, the alignment of the drop dispensing member with respect to bright pixels, etc. which do not make it possible to obtain the desired resolution. In addition, the formation of reflective walls by conformal deposition then localized etching makes it possible to obtain a strong contrast insofar as a light radiation associated with a pixel cannot reach the photoluminescent block of a neighboring pixel.
    Figures 2A to 2H illustrate a method of manufacturing an optoelectronic device 1 with light emitting diodes according to a second embodiment.
    FIG. 2A illustrates a step of supplying a matrix of light-emitting diodes followed by a step of depositing a first photosensitive resin 5i comprising first photoluminescent particles. These steps are identical or similar to those explained with reference to FIG. 1A and are not described in more detail.
    FIG. 2B illustrates a step of forming first photoluminescent pads 6i by photolithography of the first photosensitive resin 5i. This step is also similar or identical to that described with reference to fig.lB.
    FIG. 2C illustrates a step of conformal deposition of a first thin layer 9i in at least one reflective material. Unlike the first embodiment, the first thin reflective layer 9i is deposited while the second photoluminescent pads 62 are not yet formed.
    The first thin layer 9i can thus be deposited by one of the techniques mentioned above. It can be formed from the same reflective material or from a plurality of different materials deposited on top of each other, and has a substantially constant thickness, for example equal to approximately 100 nm.
    It covers the first photoluminescent studs 61 as well as the transmission surface 3 not coated with the first studs 61. Thus, it continuously covers the lateral flanks 81 and the upper surface 7i of the first photoluminescent studs 61, as well as the areas of the transmission surface 3 intended to form the other light pixels, ie here the green pixels Pg and blue pixels P B.
    FIG. 2D illustrates a step of forming first reflective walls 101, covering the lateral flanks 81 of the first photoluminescent studs 61, by localized etching of the first thin layer 9i.
    Thus, the parts of the thin layer 9i not located in contact with the lateral flanks 81 of the first photoluminescent pads 61 are etched. This eliminates the parts of the thin layer 9 which cover the upper surfaces 7i of the first photoluminescent pads 61, and those that cover the areas of the transmission surface 3 defining the green pixels Pg and blue pixels P B are deleted.
    This etching step can be carried out by dry etching, for example by one of the techniques mentioned above. Since the dry etching is highly anisotropic, only the parts of the first thin layer 9i remain covering the lateral flanks 81 of the first photoluminescent pads 61, thus forming first reflecting walls 101 which surround the first photoluminescent pads 61 in a plane parallel to the XY plane.
    2E illustrates a step of depositing a second photosensitive resin 52 on the transmission surface 3. It can be deposited by one of the techniques mentioned above, so as to cover the transmission surface 3 not coated with the first photoluminescent pads 6i. It thus comes into contact with the reflecting walls 10i of the first pads 6i, and in this example has a thickness substantially equal to that of the first photoluminescent pads 6i. The second photosensitive resin 52 comprises second photoluminescent particles, here quantum dots, similar or identical to those described in the first embodiment.
    FIG. 2F illustrates a step of forming second photoluminescent pads 62 by photolithography of the second photosensitive resin 52- In this example, they are positioned on the transmission surface 3 at the level of pixels intended to emit green light Pg [ Unlike the first embodiment, at least one second photoluminescent pad 62, and here each second photoluminescent pad 62 is located against a first photoluminescent pad 61 so as to be in contact with the corresponding first reflecting wall 101. It is here in contact with at least a first reflecting wall 101, but comprises at least one free part of the lateral flank 82, that is to say a part which is not in contact with a first reflecting wall 101.
    The second photoluminescent studs 62 are distinct from each other and are also distinct from the first photoluminescent studs 61. Each second stud 62 is however optically and structurally separated from the first stud 61 against which it is located by the first reflecting wall 101. Thus, the luminescence light radiation emitted by the first photoluminescent particles cannot be transmitted in the second photoluminescent pad 62 adjacent, nor that of the second photoluminescent particles can be transmitted in the first photoluminescent stud 61 adjacent.
    FIG. 2G illustrates a step of depositing a second thin layer 92 in a reflective material. The second thin layer 92 can be formed from one or more materials identical to that or those of the first thin layer 9i. Preferably, the second thin layer 92 is identical, in terms of material and thickness, to the first thin layer 9i.
    The second thin layer 92 is deposited so as to cover the first and second photoluminescent pads 61, 62 as well as the transmission surface 3 not coated with the photoluminescent pads 61, 62. Thus, it continuously covers the upper surfaces 7i, 72 of the first and second photoluminescent pads 61, 62, the lateral flanks 82 of the second photoluminescent pads 62, as well as the first reflecting wall 101 of the first photoluminescent pads 6i. It also covers the areas of the transmission surface 3 intended to form the blue pixels Pb. FIG. 2H illustrates a step of forming, by localized etching of the second thin layer 92, second reflective walls IO2 covering the lateral flanks 82 second photoluminescent pads 62 which are not in contact with a first reflective wall 101. Thus, the parts of the second thin layer 92 not located not in contact with the lateral flanks 82 of the second photoluminescent pads 62 are engraved. of the thin layer 92 which cover the upper surfaces 7i, 72 of the first and second photoluminescent pads 61, 62, and those which cover the areas of the transmission surface 3 defining the blue pixels Pb are eliminated [0080] This etching step can be carried out by dry etching, for example by one of the techniques mentioned above. Since the dry etching is highly anisotropic, only the parts of the second thin layer 92 remain covering the lateral flanks 82 of the second photoluminescent pads 62, thus forming second reflective walls IO2. While each first reflecting wall 101 continuously surrounds, in a plane parallel to the XY plane, the first corresponding photoluminescent pad 61, each second reflecting wall IO2 is only in contact with part of the lateral flanks 82 of the corresponding second photoluminescent pad 62 . It appears that part of the first reflecting wall 101 is covered by a part of the second reflecting wall IO2, resulting in an increased local thickness of reflecting material.
    Thus, the method according to the second embodiment makes it possible to obtain an optoelectronic device with even higher resolution, insofar as the first and second photoluminescent pads 61, 62 located against each other are only separated from each other. by a simple reflecting wall, the thickness of which may be less than 500 nm, for example equal to approximately 100 nm, or even less. We are thus able to increase the resolution of the optoelectronic device, while maintaining a strong contrast between the pixels.
    According to a variant illustrated in FIG. 3A, the light pixels are arranged so as to form a Bayer matrix, that is to say so as to form a geometric repetition of a set of several light pixels adapted to transmit at different wavelengths, for example two green pixels Pg, a red pixel Pr and a blue pixel Pb, arranged in pairs adjacent to each other.
    In this example, the same green pixel Pg is adjacent to four different red pixels Pr. More precisely, the same second photoluminescent pad 62 adapted to convert the blue excitation light into green light is bordered by four first photoluminescent pads 6i distinct from each other and adapted to convert the blue excitation light into red light. Each second pad 62 is thus in contact with the first reflecting walls 101 of the first four adjacent studs 61.
    Thus, this variant of the method according to the second embodiment does not include a step of forming second reflective walls IO2 covering the lateral flanks 82 of the second pads 62. Indeed, during the deposition of the second photosensitive resin 52 , this fills the spaces formed between the first photoluminescent pads 61, and more precisely the spaces formed between the first reflective walls 101 facing each other. The second photosensitive resin 52 is then removed by photolithography in the areas intended to form blue light pixels P B. The second photoluminescent pads 62 thus formed are therefore in contact with reflective walls 101 of several first neighboring photoluminescent pads 61. They are therefore delimited laterally, in the XY plane, by the first reflecting walls 101.
    Other arrangements of the light pixels are of course possible. Thus, in the example of FIG. 3B, along the X axis, the first photoluminescent pads 61 are spaced two by two either by a second photoluminescent pad 62 or by an area of the transmission surface 3 intended to form a blue pixel P B.
    According to another variant illustrated in Figure 3B, the reflecting walls 101 are inclined relative to the plane XY. By inclined is meant that the reflecting walls 101 have an angle of inclination different from 90 ° relative to the plane XY. This tilt angle can thus be strictly less than 90 ° and greater than or equal to a non-zero maximum tilt value, for example equal to about 20 °. They are here substantially flat and have a substantially constant local angle of inclination. The first photoluminescent studs 61, preferably adapted to convert the excitation light into red, have a truncated pyramidal shape, that is to say that the size of the upper surface 7i is less than that of the base of the stud in contact with the transmission surface 3.
    In contrast, the second photoluminescent phots 62, preferably adapted to convert the excitation light into green, have a flared shape, in the sense that the size of the upper surface 72 is greater than that of the base. They thus have the shape of a truncated inverted pyramid. The fact that the second photoluminescent studs 62 have a flared shape towards the outside makes it possible to improve the light extraction of the luminescence radiation. It thus makes it possible to limit the possible reabsorption of luminescence radiation by the same photoluminescent particles, which is particularly advantageous when these are adapted to emit luminescence light in the green.
    Alternatively, the reflecting walls 101, IO2 may not be planar, but may have a curved shape, in particular when the first photoluminescent studs 61 have substantially curved side flanks 81. The term “curve” is understood to mean in particular a surface which does not have a flat zone, or which is formed of a succession of flat zones inclined two by two. It is then possible to limit the partial etching of the reflective walls 101, IO2 during the step of dry etching of the reflective thin layers 9i, 92, while optimizing the light extraction and limiting the reabsorption of luminescence light from the second photoluminescent studs 62.
    In general, light emitting diodes can have different types of structures. FIGS. 4A and 4B illustrate an example of light-emitting diodes 4 of the wired type, here in the so-called core-shell configuration.
    Referring to Figure 4A, the optoelectronic device comprises an optoelectronic chip 2 in which is located the matrix of light emitting diodes 4. Each light pixel thus comprises a plurality of wired light emitting diodes 4. The light-emitting diodes 4 can be uniformly distributed in each light pixel, and form sets of diodes electrically distinct from each other. Thus, each set of diodes belongs to a light pixel, which can be activated independently of the other sets of diodes. In the same assembly, the light-emitting diodes 4 are connected in parallel, so as to transmit simultaneously when the corresponding pixel is activated.
    The light emitting diodes 4 rest on a support layer 25, for example a growth substrate. In the case where the growth substrate 25 is electrically insulating, electrical lines (not shown) may be present inside the substrate 25 to allow the polarization of the different pixels of light-emitting diodes 4. In the case of a substrate of electrically conductive growth, for example made from silicon, insulating trenches (not shown) can be provided to electrically isolate the pixels from each other. Furthermore, the support layer 25 can be fixed and electrically connected to a control chip (not shown) adapted to provide electrical control of the optoelectronic device.
    The light emitting diodes 4 are coated with at least one spacer layer 12, the face opposite to the support layer forms the transmission surface 3. The spacer layer 12 is transparent to the light radiation emitted by the light emitting diodes. 4. It can be formed of a passivation layer, made of a dielectric material, and possibly of a planarization layer. The dielectric material can be chosen from an oxide, a nitride or even a silicon oxynitride. Other materials may also be suitable. The planarization layer can be formed from an organic or mineral material, such as silicone or PMMA. The spacing layer has a thickness greater than the longitudinal dimension, along the axis Z, of the light-emitting diodes 4, so as to cover them uniformly.
    FIG. 4B illustrates an example of light-emitting diode 4 belonging to the same light pixel, of the wired type in the core / shell configuration. The light-emitting diode 4 has an elongated three-dimensional shape and extends longitudinally along an axis parallel to the axis Z. In this example, it comprises a first doped portion 21, for example of the n type, in the form of a wire which extends longitudinally from a nucleation pad 24 which rests on a front face of a growth substrate 25. A growth mask 26 made of a dielectric material covers the front face of the substrate 25 and has an opening opening onto the nucleation pad 24. The nucleation pads 24 may be pads distinct from each other, or even different zones of the same continuous thin layer. An upper part of the first doped portion 21 is covered, at its upper border and its lateral border, by one or more layers forming an active region 23 which comprises at least one quantum well. The active area 23 is itself covered by a layer forming a second doped portion 22, here of the p type. The light-emitting diodes 4 are here of nanowires or microfils in heart / shell configuration, the doped portion 21 and the doped portion 22 respectively form the heart and the shell of the wire.
    The light emitting diodes 4 of the same light pixel are here electrically connected in parallel. The rear face of the substrate 25, here electrically conductive, is coated with a first polarization electrode 27, and the doped portions 22 are covered with a continuous layer forming a second polarization electrode 28. Finally, the spacer layer 12 completely covers the light-emitting diodes 4. It has an upper face, here substantially planar, which forms the transmission surface 3 of the matrix of light-emitting diodes 4.
    FIG. 4C illustrates another example of light-emitting diode 4 belonging to the same light pixel, of wired type in axial configuration. In this example, the wire is formed by a stack of the first doped portion 21, of the active area 23, and of the second doped portion 22, which extends along a longitudinal axis parallel to the axis Z. At the Unlike the core / shell configuration, the active area 23 only substantially covers the upper edge of the doped portion 21, and the doped portion 22 only substantially covers the upper edge of the active area 23. As before, the wire s extends longitudinally from a nucleation pad 24 which rests on a front face of a growth substrate 25. The growth mask 24 covers the front face of the substrate 25 and has an opening opening onto the nucleation pad 24. The spacer layer covers the lateral edge of the wire, and is crossed by the second bias electrode 28 which comes into contact with the upper edge of the second doped portion 22. The spacer layer 12 pr feel an upper face which forms the transmission surface 3.
    Purely by way of illustration, the light-emitting diodes 4 can be produced based on GaN and be adapted to emit excitation radiation in blue. They can have transverse dimensions of between πm and πm, for example between πm and 5 pm. The height is greater than the transverse dimensions, for example 2 times, 5 times, and preferably at least 10 times greater, and can be equal to approximately πm.
    FIG. 5 illustrates an optoelectronic device in which the light-emitting diodes 4 have a mesa structure. In this example, each light pixel comprises a single light-emitting diode 4 which can be activated independently of the other diodes 4.
    The light-emitting diodes 4 are each formed of a stack of a first doped portion 31, here of the n type, and of a second doped portion 32, here of the p type, between which is located an active area 33. They form mesa structures that are substantially coplanar with each other. This structure of light-emitting diodes 4 is similar or identical to that described in document EP2960940. By mesa structure is meant a structure formed by a stack of semiconductor portions 31, 32, 33 located projecting above a growth substrate following an etching step. The mesa structures are substantially coplanar in the sense that the first doped portions 31 of the light-emitting diodes 4 are respectively coplanar. It is the same for the active zones 33 and the second doped portions 32.
    Each light-emitting diode 4 has a first doped portion 31, a surface opposite to the active area 33 is a surface through which the light radiation from the diode 4 is emitted. The lateral flanks of the first doped portion 31 and of the second doped portion 32, as well as those of the active area 33, are covered with a dielectric layer 34, with the exception of a detachment surface 35 of the first doped portion 31.
    The light emitting diodes 4 are separated from each other by lateral elements 36 of electrical connection which extend along the axis Z between the diodes. Each light-emitting diode 4 is thus associated with a lateral connection element 36 which comes into electrical contact with the detachment surface 35 of the first doped portion 31, making it possible to apply a determined electrical potential to the first doped portion 31. This lateral element 36 connection is however electrically isolated from the adjacent diodes 4 by the dielectric layers 34 thereof.
    The optoelectronic chip 2 in this example comprises a layer 37 known as an electrical connection, which participates in forming a support layer, the layer 37 allowing electrical contact between a control chip (not shown) and the lateral connection elements 36 electrical, and electrical connection portions 38 located in contact with the second doped portions 32. The connection layer 37 thus comprises connection pads 39 electrically isolated from each other by a dielectric material. Thus, the control chip can apply an electrical potential to one and / or the other of the light-emitting diodes 4, and thus activate them independently of each other.
    The spacer layer 12 here comprises a passivation layer of a dielectric material covers the emission face of the first doped portions 31 of the light emitting diodes 4, as well as the lateral connection elements 36, optionally supplemented with a layer planarization. The face of the spacer layer 12 opposite to the light-emitting diodes 4 forms the transmission surface 3 of the diode array.
    Purely by way of illustration, the light-emitting diodes 4 can be produced based on GaN and be adapted to emit light radiation in blue. They may have a thickness of between 100 nm and 50 μm, and the lateral dimensions may be between 500 nm and a few hundred microns, and preferably are less than 50 μm, preferably at 30 μm, and may be equal to 10 μm or even 5 μm.
    As a variant to the first and second embodiments in which the photoluminescent pads 6 are directly produced on an emitting surface 3 of a matrix of light-emitting diodes, the steps of forming the photoluminescent pads 6 and reflecting walls 10 can be carried out on a so-called support surface of a plate transparent to the light radiation emitted by the light-emitting diodes, the transparent plate then being attached and fixed to the matrix of light-emitting diodes, for example on the spacer layer. The method according to this variant is then similar to those of the first and second embodiments described above, the emission surface 3 then being a surface of the transparent plate. The transparent plate can be made of glass, in particular borosilicate glass, for example pyrex or sapphire, or any other suitable material. It has a thickness allowing its manipulation and therefore its transfer to the diodes. The fixing of the transparent plate on the matrix of light-emitting diodes, for example on the spacing layer mentioned above, can be carried out by any means, for example by bonding using an adhesive transparent to the light radiation emitted by the diodes. After the step of transferring the transparent plate onto the matrix of light-emitting diodes, the photoluminescent pads are each located opposite at least one light-emitting diode.
    FIGS. 6A to 61 illustrate a method of manufacturing an optoelectronic device 1 with light-emitting diodes according to a third embodiment, which differs from the first and second embodiments essentially in that the diodes are of the wired type and are located inside photosensitive resin pads, some or all of which are photoluminescent. By located inside, it is meant that the photosensitive resin pad surrounds each of the corresponding light-emitting diodes in the XY plane and covers them along the Z axis. The light-emitting diodes are therefore in contact with the photosensitive resin of the pad and do not are not spaced apart by the spacer layer as in the first and second embodiments.
    [00106] FIG. 6A illustrates a step of supplying a matrix of light-emitting diodes of the wired type, and preferably in the core / shell configuration. The light-emitting diodes 4 here have a structure identical or similar to that shown in FIG. 4B, with the exception of the spacer layer 12. They thus take the form of an elongated three-dimensional structure, which extends along a longitudinal axis parallel to the Z axis from the surface of a support layer, for example the growth substrate 25.
    The light-emitting diodes 4 are arranged on the support layer 25 by sets of light-emitting diodes intended to form light pixels of different emission colors, for example here blue pixels P B , red P R , and green Pg Thus preferably, the diodes of the same set, and therefore of the same light pixel, are electrically connected in parallel, and each set of diodes is electrically independent of the other sets. By way of illustration, the light-emitting diodes 4 may have a height equal to approximately 10 μm. In this example, they are made based on GaN and are adapted to emit blue excitation light.
    FIG. 6B illustrates a step of depositing on a support surface 3 ’, here the surface of the support layer 25, of a first photosensitive resin 5i comprising first photoluminescent particles. The photosensitive resin 5i is in contact with and covers the surface 3 ’of the support layer 25, and is in contact with and covers each light-emitting diode 4 at its emitting surface. It thus extends, in a plane parallel to the XY plane, between each of the light-emitting diodes 4, and has a thickness greater than the height of the light-emitting diodes 4. By way of illustration, the first photosensitive resin 5i can have a thickness equal to 20 μm about. The first photoluminescent particles can here be adapted to convert blue excitation light emitted by light-emitting diodes 4 into red light. They are quantum dots here, whose average size is less than 50 nm.
    FIG. 6C illustrates a step of forming first photoluminescent pads 61 by photolithography of the first photosensitive resin 5i. The first photoluminescent pads 6i are located at the level of zones intended to form red light pixels Pr. Each first pad 6i thus covers and extends between the light-emitting diodes 4 of the corresponding pixel Pr. In other words, the diodes 4 of the pixels Pr are located inside the first pads 6i, and are not located remotely as in the first and second embodiments described above. By way of illustration, the first pads 6i have a thickness substantially equal to 20 μm and a width substantially equal to 10 μm. The first photoluminescent pads have a width such that each first pad 6i extends at the level of the corresponding light pixel P R , and does not extend over the areas intended to form the neighboring light pixels of other colors Pb and Pg- Les zones intended to form luminous pixels of other colors, for example here blue Pb and green Pg, do not comprise first photoluminescent pads 6i.
    FIG. 6D illustrates a step of depositing a second photosensitive resin 52 comprising second photoluminescent particles. These are different from the first photoluminescent particles in the sense that their emission spectrum is different from that of the first photoluminescent particles. In this example, they are suitable for converting blue excitation light emitted by light-emitting diodes 4 into green light. Here they are quantum dots, the average size of which is less than 50 nm. The second resin 52 is in contact with and covers the surface 3 ’of the support layer 25, and is in contact with and covers each light-emitting diode 4 not located in the first pads 6i. It thus extends, in a plane parallel to the XY plane, between the light-emitting diodes 4 situated at the level of the zones intended to form blue Pb and green Pg light pixels, and has a thickness greater than the height of the light-emitting diodes 4. A As an illustration, the second photosensitive resin 52 may have a thickness substantially equal to approximately 20 μm.
    Figure 6E illustrates a step of forming second photoluminescent pads 62 by photolithography of the second photosensitive resin 52- The second pads 62 are located at the areas intended to form green light pixels Pg- Each second pad 62 thus covers the light emitting diodes 4 of the corresponding pixel Pg, and extends between the diodes 4 while being in contact with the latter. In other words, the diodes 4 of the pixels Pg are located inside the second pads 62. By way of illustration, the second pads 62 have a thickness substantially equal to 20pm and a width substantially equal to 10pm. The second pads 62 have a width such that each second pad 62 extends at the level of the corresponding light pixel Pg, and does not extend over the areas intended to form the neighboring blue light pixels Pb- The areas intended to form pixels bright blue Pb do not have second photoluminescent studs 62.
    6F illustrates a step of depositing a third photosensitive resin 53 so that it covers the diodes located in areas intended to form blue pixels Pb- It comes into contact and covers the surface 3 'of the support layer 25. The third photosensitive resin 53 may or may not comprise third photoluminescent particles different from the first and second photoluminescent particles. In the case where it does not comprise photoluminescent particles, the light pixel Pb is adapted to emit light whose spectrum corresponds to that of the light-emitting diodes. In this example, it comprises third photoluminescent particles, here quantum dots whose average size is less than 50 nm, adapted to convert the blue excitation light emitted by the light-emitting diodes 4 into blue light of another length of wave. For example, the diodes can emit at a wavelength of around 450nm and the third particles can be adapted to emit luminescence light at around 480nm. The third resin 53 is in contact and covers the surface of the support layer, and is in contact and covers each diode 4 not located in the first and second pads 61 and 62. It thus extends, in a plane parallel to the XY plane , between the light-emitting diodes 4 located at the areas intended to form blue light pixels Pb, and has a thickness greater than the height of the light-emitting diodes 4. For illustrative purposes, the third photosensitive resin 53 may have a thickness substantially equal to approximately 20 μm .
    FIG. 6G illustrates a step of forming third pads 63, here photoluminescent pads, by photolithography of the third photosensitive resin 53- The third pads 63 are located at the areas intended to form blue luminous pixels Pb- Each third pad 63 covers and extends between the diodes 4 of the corresponding pixel Pb, while being in contact with them. In other words, the diodes 4 of the pixels Pb are located inside the third pads 63. By way of illustration, the third pads 63 have a thickness substantially equal to 20pm and a width substantially equal to 10pm. The third pads 63 have a width such that each third pad 63 extends at the level of the corresponding blue light pixel Pb.
    FIG. 6H illustrates a step of conformal deposition of a thin layer 9 in at least one reflective material, for example at least one metallic material, so as to cover the first, second and third pads 61, 62, 63. The thin layer thus continuously covers the upper surfaces 7, 72, 73 and the lateral flanks 81, 82, 83 of the pads 61, 62, 63. It can have a substantially uniform thickness, for example equal to approximately 100 nm at the lateral flanks 8 of the studs 6.
    FIG. 61 illustrates a step of forming the reflecting walls 101, IO2, IO3 covering the lateral flanks 81, 82, 83 by local etching of the thin layer 9. Thus, here, by etching, the parts of the thin layer 9 which covers the upper surfaces 7i, 72, 73. There is also etching of the parts of the thin layer 9 which rest on the surface 3 'of the support layer 25.
    Thus, by the manufacturing method according to the third embodiment, one is able to obtain an optoelectronic device whose light-emitting diodes, of wired type, are located inside the photosensitive resin pads, including at at least part of the pads is photoluminescent. A high resolution can be obtained by the fact that the photosensitive resin pads are produced by photolithography and by the fact that the photoluminescent particles are quantum dots.
    FIG. 7 illustrates a variant of the method according to the third embodiment in which the reflective thin layer 9 is deposited so that its thickness at the level of the lateral flanks 81, 82, 83 of the pads 61, 62, 63 is greater than half the distance between two neighboring plots in the XY plane. Thus, during the step of depositing the thin layer 9, contact is obtained between the reflecting walls 10 facing one another of two neighboring studs 6.
    In a variant of FIG. 7 and of the third embodiment described above, the reflective walls 10 can be formed by electrochemical deposition. More specifically, as illustrated in FIGS. 6A-6G, the pads 6 of photosensitive resin are produced, which rest on a surface 3 ′ of the support layer 25. A thin growth track, made of at least one metallic material, for example made of titanium, copper, or aluminum, is located on the surface 3 ′ of the support layer 25, and extends between the adjacent studs 6 in pairs, so as to surround each of the studs 6. Then, as a variant in FIGS. 6H and 61, the reflective walls 10 are produced by electrochemical deposition of a reflective material, such as a metal, for example nickel, aluminum or silver. The metal then grows from the thin growth layer, and fills the space delimited by the lateral flanks 8 facing each other. The metal thus covers the lateral sides of the studs 6 and forms the reflective walls. The optoelectronic device 1 is then similar to that illustrated in FIG. 7 in that the reflective walls 10 fill the space formed between the neighboring studs 6. By way of illustration, the distance between two neighboring studs 6 can be between 0.5pm and 5pm.
    As an alternative to the method according to the third embodiment described above, the first, second, third photoluminescent pads 6, as well as the corresponding reflecting walls 10, can be carried out successively. More specifically, similarly to the second embodiment, the formation of the first photoluminescent pads 6i is carried out, followed by the formation of the first reflective walls 101, then the formation of the second photoluminescent pads 62 is carried out, followed by the formation of the second walls reflective IO2, and so on.
    Particular embodiments have just been described. Different variants and modifications will appear to those skilled in the art. Thus, the light emitting diodes can be adapted to emit excitation light in a color other than blue, and the various photoluminescent studs can be adapted to convert the excitation light into colors other than red and green. In addition, the photosensitive resin pads may not contain photoluminescent particles. Furthermore, in general, the photoluminescent pads 6 may have dimensions, in thickness and / or in width, different from each other.
    权利要求:
    Claims (17)
    [1" id="c-fr-0001]
    1. Method for producing an optoelectronic device (1) comprising a matrix of light-emitting diodes (4) and a plurality of photoluminescent studs (6i, 62, 63 ...) each located opposite at least a part of said light-emitting diodes (4), comprising the following steps:
    o formation of said plurality of photoluminescent pads (61, 62, 63 ...) by photolithography of at least one photosensitive resin (5i, 52, 53 · ..) containing photoluminescent particles previously deposited on a support surface (3; 3 ');
    o formation of reflective walls (101, IO2, IO3 ---) covering lateral flanks (81, 82, 83 ...) of said photoluminescent pads (61, 62, 63 ...), by depositing at least one portion of thin layer (9i, 92, 93 ...) on the lateral flanks (81, 82, 83 ...).
    [2" id="c-fr-0002]
    2. Method according to claim 1, in which the step of forming the reflective walls (101, IO2, IO3) comprises a conformal deposition of at least one thin layer (9i, 92, 93) in a reflective material so as to cover the photoluminescent pads (61, 62, 63), then localized etching of the thin layer (9i, 92, 93) deposited, so as to make free a so-called upper surface (7i, 72, 73) of the photoluminescent pads (61, 62, 63) opposite said support surface (3; 3 ').
    [3" id="c-fr-0003]
    3. Method according to claim 2, in which the steps of forming the plurality of photoluminescent pads (61, 62), and of forming the reflective walls (10i, IO2) comprise the following steps:
    o formation of a plurality of first photoluminescent pads (61), by photolithography of a first photosensitive resin (5i) containing first photoluminescent particles previously deposited on said support surface (3; 3 ’);
    formation of first reflective walls (101) covering lateral flanks (81) of said first photoluminescent pads (61) by conformal deposition of a thin reflective layer (91) on the first photoluminescent pads (61), then localized etching so as to freeing an upper surface (7i) of the first photoluminescent pads (61);
    o formation of a plurality of second photoluminescent pads (62), by photolithography of a second photosensitive resin (52) containing second photoluminescent particles previously deposited on said support surface (3; 3 '), the second photoluminescent particles being different from first photoluminescent particles.
    [4" id="c-fr-0004]
    4. Method according to claim 3, comprising, following the step of forming the plurality of second photoluminescent pads (62), a step of:
    o formation of second reflecting walls (IO2) covering lateral flanks (82) of said second photoluminescent pads (62) by conformal deposition of a thin reflective layer (92) on the first and second photoluminescent pads (61, 62), then etching localized so as to free the upper surface (7i, 72) of the first and second photoluminescent pads (61, 62).
    [5" id="c-fr-0005]
    5. Method according to claim 3 or 4, wherein each second photoluminescent pad (62) is in contact with at least one first reflecting wall (101).
    [6" id="c-fr-0006]
    6. Method according to any one of claims 2 to 5, wherein each first reflective wall (101) has a thickness between lOnm and 500nm.
    [7" id="c-fr-0007]
    7. The method of claim 1, wherein the step of forming the plurality of photoluminescent pads (61, 62, 63) comprises at least a formation of several first photoluminescent pads (61) containing first photoluminescent particles followed by a formation of several second photoluminescent pads (62) containing second photoluminescent particles different from the first photoluminescent particles, the step of forming the reflective walls (101, IO2, IO3) being carried out after the formation of at least the first and second photoluminescent pads (61, 62).
    [8" id="c-fr-0008]
    8. The method of claim 7, wherein the reflective walls (101, IO2, IO3) are formed by electrochemical deposition.
    [9" id="c-fr-0009]
    9. Method according to any one of claims 1 to 8, in which the photoluminescent particles are quantum dots, and have an average size less than or equal to 50nm.
    [10" id="c-fr-0010]
    10. Method according to any one of claims 1 to 9, in which the light-emitting diodes (4) are elongated three-dimensional elements extending longitudinally substantially orthogonal to a main plane of a support layer (25, 37).
    [11" id="c-fr-0011]
    11. Method according to any one of claims 10, in which the light-emitting diodes (4) are situated inside the pads (6i, 62, 63) of photosensitive resin, at least part of the pads (61, 62 , 63) are photoluminescent studs comprising photoluminescent particles.
    [12" id="c-fr-0012]
    12. Method according to any one of claims 1 to 10, in which the photoluminescent pads (61, 62, 63) rest on a support surface (3), called transmission surface, formed by a spacer layer (12) covering the light-emitting diodes (4).
    [13" id="c-fr-0013]
    13. Optoelectronic device (1), comprising:
    o an array of light emitting diodes (4) resting on a support layer;
    a plurality of first photoluminescent pads (61), each located opposite at least a portion of said light-emitting diodes (4), each formed of a first photosensitive resin (5i) comprising first photoluminescent particles, having lateral flanks (81) covered by a portion of deposited thin layer forming a first reflecting wall (101);
    o a plurality of second photoluminescent pads (62), each located opposite at least a portion of said light-emitting diodes (4), each formed of a second photosensitive resin (5 2 ) comprising second different photoluminescent particles first photoluminescent particles, having lateral flanks (82) covered by a portion of deposited thin layer forming a second reflecting wall (IO2).
    [14" id="c-fr-0014]
    14. Optoelectronic device (1) according to claim 13, in which each second photoluminescent stud (62) is in contact with a first reflecting wall (101).
    [15" id="c-fr-0015]
    15. Optoelectronic device (1) according to claim 13 or 14, wherein the light emitting diodes (4) have a three-dimensional structure elongated along a longitudinal axis substantially orthogonal to the support layer (25, 37).
    [16" id="c-fr-0016]
    16. Optoelectronic device (1) according to claim 15, wherein the light emitting diodes (4) are located inside the photoluminescent pads (61, 62).
    [17" id="c-fr-0017]
    17. Optoelectronic device (1) according to claim 14, in which the light-emitting diodes (4) have a mesa structure.
    1/7
    P G
    Pr
    6 ί r
    Pb
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    同族专利:
    公开号 | 公开日
    KR20190099050A|2019-08-23|
    FR3061358B1|2021-06-11|
    JP2020507201A|2020-03-05|
    CN110337721A|2019-10-15|
    US20190334064A1|2019-10-31|
    EP3563420B1|2021-06-16|
    EP3563420A1|2019-11-06|
    US11171267B2|2021-11-09|
    WO2018122520A1|2018-07-05|
    TW201824607A|2018-07-01|
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    法律状态:
    2017-12-21| PLFP| Fee payment|Year of fee payment: 2 |
    2018-06-29| PLSC| Publication of the preliminary search report|Effective date: 20180629 |
    2019-12-20| PLFP| Fee payment|Year of fee payment: 4 |
    2020-12-28| PLFP| Fee payment|Year of fee payment: 5 |
    2021-12-17| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1663410|2016-12-27|
    FR1663410A|FR3061358B1|2016-12-27|2016-12-27|MANUFACTURING PROCESS OF AN OPTOELECTRONIC DEVICE INCLUDING PHOTOLUMINESCENT PHOTORESIN PLOTS|FR1663410A| FR3061358B1|2016-12-27|2016-12-27|MANUFACTURING PROCESS OF AN OPTOELECTRONIC DEVICE INCLUDING PHOTOLUMINESCENT PHOTORESIN PLOTS|
    KR1020197021614A| KR20190099050A|2016-12-27|2017-12-22|Process for manufacturing optoelectronic device comprising photoluminescent pads of photoresist|
    US16/473,807| US11171267B2|2016-12-27|2017-12-22|Process for fabricating an optoelectronic device including photoluminescent pads of photoresist|
    CN201780087300.XA| CN110337721A|2016-12-27|2017-12-22|Method for manufacturing the photoelectric device of the luminescence generated by light pad comprising photoresist|
    EP17832297.0A| EP3563420B1|2016-12-27|2017-12-22|Process for fabricating an optoelectronic device including photoluminescent pads of photoresist|
    JP2019534647A| JP2020507201A|2016-12-27|2017-12-22|Method of manufacturing optoelectronic device including photoluminescence pad of photoresist|
    PCT/FR2017/053826| WO2018122520A1|2016-12-27|2017-12-22|Process for fabricating an optoelectronic device including photoluminescent pads of photoresist|
    TW106145949A| TWI754711B|2016-12-27|2017-12-27|Method for manufacturing an optoelectronic device including photoluminescent pads of photoresist|
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