Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/005—Processes
  • H01L33/0095—Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
  • H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
  • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
  • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
  • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
  • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
• • 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
  • H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
  • H01L27/153—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars
  • H01L27/156—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission in a repetitive configuration, e.g. LED bars two-dimensional arrays
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/005—Processes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
  • H01L2933/0008—Processes
  • H01L2933/0033—Processes relating to semiconductor body packages
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
  • H01L2933/0008—Processes
  • H01L2933/0033—Processes relating to semiconductor body packages
  • H01L2933/0066—Processes relating to semiconductor body packages relating to arrangements for conducting electric current to or from the semiconductor body
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
  • H01L33/16—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
  • H01L33/18—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous within the light emitting region
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
  • H01L33/20—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
  • H01L33/24—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate of the light emitting region, e.g. non-planar junction
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
  • H01L33/26—Materials of the light emitting region
  • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
  • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/36—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
  • H01L33/40—Materials therefor
  • H01L33/42—Transparent materials

Definitions

• TITLE Manufacturing process of a set of light emitters
• the present invention relates to a method of manufacturing an assembly of light emitters.
• the present invention also relates to a method of manufacturing an associated screen.
• Many display screens have a set of light emitters that are used to form the image displayed on the screen. These emitters each play the role of an image element or “pixel” (in particular when the screen is monochrome), or of a portion of such an image element, called a “sub-pixel” (in particular. when the screen is a color screen, each pixel comprising sub-pixels of a different color, the selective lighting of which makes it possible to modify the color of the pixel).
• These light emitters generally comprise a light emitting structure, such as a light emitting diode or a backlighting system accompanied by a liquid crystal, making it possible to emit the desired radiation, and electrical contacts making it possible to connect the structure. emitting light to a control circuit so as to supply electric power to the emitting structure when it is desired that the associated radiation be emitted.
• the contacts are necessarily electrically isolated from each other, so that the light emitters can be controlled independently.
• Light emitters are mostly produced simultaneously as a plate with multiple light emitters, each contact being carried by one side of the plate.
• the plate is then either used as it is in a display screen, or cut to separate the emitters from each other, these emitters then each being integrated into a screen or other light device.
• transmitters do not perform optimally. For example, defects that appear during the manufacture of transmitters can lead to non-functional transmitters. In other cases, some transmitters will require electrical currents with higher currents or voltages than in the case of transmitters with nominal performance.
• This detection generally involves supplying electricity to each transmitter and studying its behavior. when it is powered, in particular to check that the expected radiation is actually emitted, and what electric current is necessary for this.
• a method for manufacturing a set of light emitters each comprising a light emitting structure, a first electrical contact and a second electrical contact the process comprising the steps of:
• each emitting structure being configured to emit a first radiation when an electric current flows through the emitting structure
• the manufacturing stage includes:
• each first contact and at least one first conductor a first set of at least two first contacts being defined, each first contact of the first set being electrically connected to each other first contact of the first set by the first conductor (s),
• the emitting structures of the first set are electrically connected in a simple manner to an electrical source since the associated first contacts are electrically connected to each other.
• a respective connector such as a wire or a tip.
• a single such connector in contact with one of these first contacts, with one of the first conductors or with the first contact pad, is sufficient to inject an electric current into each of the emitting structures of the first set.
• first contacts are less damaged during each injection step, since it is not necessary to apply an electrical connector against each of the first contacts: a single electrical connector is sufficient to supply each first contact of the first set. .
• the subsequent connection of each first contact with a control circuit when the corresponding light emitter is integrated into a light device is then of better quality and the reliability of the device incorporating the light emitter 10 is improved.
• the method comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:
• the method further comprises, following the first observation step, a step of removing each first conductor.
• the forming step comprises the deposition, on the first face, of a layer of an electrically conductive material to form each first contact and each first conductor, each first conductor being removed, during the removal step, by etching of said layer.
• each first contact is placed opposite the corresponding sending structure.
• a second set of first contacts comprising at least two first contacts, the first set and the second set being separate, the forming step comprising the formation of at least one second conductor, each first contact of the second set being electrically connected to each other first contact of the second set by the second conductor (s), the method further comprising a second injection step, for each first contact belonging to the second set, a second electric current passing through the first contact considered and the emitting structure corresponding to said first contact, and a second step of observing, through the first face, a radiation emitted by at least one emitting structure in response to the injection of the second electric current.
• the first set comprises a plurality of first sub-assemblies
• the second assembly comprising a plurality of second sub-assemblies
• the first contacts of each first or second sub-assembly being arranged along a specific line of said sub-assembly, each clean line extending in a first direction on the first face, the clean lines being parallel to each other and offset with respect to each other in a second direction perpendicular to the first direction, the clean lines of the first and second sub-assemblies being alternated in the second direction.
• the forming step further comprises the formation of a first connection area and a second connection area on the first face, the first connection area being electrically connected to each first conductor, the second area of connection being electrically connected to each second conductor, each first electric current being injected via the first connection pad, each second electric current being injected via the second connection pad.
• the withdrawal step includes the withdrawal of each second conductor
• each first contact belongs to the first or the second set.
• the emitted radiation is observed through the first face.
• each emitting structure comprises a light-emitting diode, each first electrical contact being in particular electrically connected to a cathode of the light-emitting diode.
• the set of light emitters has a single second contact common to all light emitters.
• the set of light emitters has a plurality of second contacts.
• At least two second contacts, in particular all of the second contacts, are electrically connected to each other.
• the second observation step includes a step of detecting a defective emitting structure.
• the first observation step comprises the measurement, for each first contact, of a light intensity of a radiation passing through the first face in a zone surrounding the first contact, and the detection of a defective emitting structure when the intensity measured light is strictly below a predetermined threshold.
• the detection step comprises storing, in a memory, information relating to the positioning of at least one defective transmitter structure.
• the method comprises a step of separating the light emitters from one another and a step of discarding each defective light emitter as a function of the stored information.
• the method further comprises a step of providing a control circuit, and a step of connecting the first electrical contact and the second electrical contact of each light emitter to the control circuit.
• connection step is carried out after the disposal step.
• Figure 1 is a partial schematic sectional view of a first example of a set of light emitters according to the invention, each light emitter comprising at least one emitting structure and a first contact,
• Figure 2 is an enlarged sectional view of a light emitter of Figure 1, showing in particular an example of an emitting structure,
• FIG. 4 is a flowchart of the steps of a method of manufacturing the first example of a set of light emitters, comprising a step of forming the first contacts,
• Figure 5 is a partial schematic sectional view of the assembly of light emitters at the end of the training step
• Figure 6 is a front view of the light emitter assembly of Figure 1 after the training step, showing the first contacts
• Figure 7 is a view similar to Figure 6, in the case of a second example of a manufacturing process
• Figure 8 is a view similar to Figure 6, in the case of a third example of a manufacturing process
• Figure 9 is a view similar to Figure 2 corresponding to another example of a set of light emitters.
• Figure 10 is a front view of the light emitter assembly of Figure 9, in their condition after the training step.
• a first example of a set of light emitters 10 is shown in Figure 1.
• the light emitter assembly 10 includes, for example, a plate 11 having each light emitter 10.
• the plate 11 includes, for example, a substrate 12 carrying each light emitter 10.
• the plate 11 has a first face 20 and a second face 22.
• the first face 20 and the second face 22 delimit the plate 11 in a direction normal to the plate 11.
• a holding device also called a "handle” provided to allow the gripping of the plate 11 by an operator or a robot is attached to the plate 11.
• the holding device is removably attached to the second side 22.
• Each light emitter 10 is configured to emit a first radiation.
• Each first radiation includes a first set of electromagnetic waves.
• a wavelength is defined for each electromagnetic wave.
• Each first set corresponds to a first range of wavelengths.
• the first range of wavelengths is the group formed by the set of wavelengths of the first set of electromagnetic waves.
• a first average wavelength is defined for each first range of wavelengths.
• Each first radiation is, in particular, visible radiation.
• First radiation with a first average wavelength between 400 nanometers (nm) and 800 nm is an example of visible light.
• the set of light emitters 10 is, for example, intended to be integrated into a display screen.
• each light emitter 10 is provided to form part of an image element 15, also called a “pixel” from the English “Picture Element”, or “sub-pixel” when the light emitter 10 is designed to emit one color among different colors that a same pixel is configured to emit.
• the light emitters 10 of the set of light emitters 10 are, for example, intended to be integrated into a single display screen. In this case, all of the light emitters 10 and the substrate 12 which carries them are, in particular, integrated together with the display screen. In this case, the relative positioning of the light emitters 10 with respect to each other is not changed when the light emitters 10 are integrated into the screen.
• the light emitters 10 are designed to be separated from one another, for example by a cutout of the substrate 12, and then individually integrated into one or more separate screens.
• the same set of light emitters 10 is likely to include light emitters 10 integrated into separate screens, and / or the relative positioning of the light emitters 10 with respect to each other is likely to be. modified when the light emitters 10 are integrated into the screen (s).
• Each pixel 15 groups together one or more light emitters 10 neighboring one another. For example, when the screen is a monochrome screen, each pixel 15 has a unique light emitter 10.
• each pixel 15 comprises several light emitters 10, at least one of the light emitters 10 being configured to emit a first radiation having an average wavelength different from the average wavelengths of the others. light emitters 10 of the same pixel 15.
• At least one of the light emitters 10 is configured to emit a first blue radiation, at least one of the light emitters 10 is configured to emit a first green radiation, and at least one of the light emitters 10 is configured to emit a first red radiation.
• a first blue radiation has, for example, an average wavelength between 430 nm and 495 nm.
• a first green radiation has, for example, an average wavelength of between 500 nm and 560 nm.
• a first red radiation has, for example, an average wavelength between 580 nm and 700 nm.
• each pixel 15 has four light emitters 10.
• one of the light emitters 10 is configured to emit a first blue radiation
• one of the light emitters 10 is configured to emit a first radiation.
• green and the other two light emitters 10 are each configured to emit a first red radiation.
• the number of light emitters 10 of each pixel 15 may vary.
• each first radiation is identical to the other first rays.
• each first radiation is blue radiation, or else ultraviolet radiation.
• each pixel 15 comprises, for at least one of the light emitters 10, a light converter.
• the light converter is made of a conversion material.
• the conversion material is configured to convert the first radiation emitted by the light emitter 10 into a second radiation.
• the conversion material is configured to be excited by the first radiation and to emit the second radiation in response.
• the second radiation has a second range of wavelengths.
• the second track is separate from the first track.
• the second place has a second average wavelength, the second average wavelength being different from the first average wavelength.
• the second average wavelength is, in particular, strictly greater than the first average wavelength.
• the conversion material is, for example, a semiconductor material.
• the conversion material is a non-semiconductor material such as doped yttrium-aluminum garnet.
• the conversion material can be an inorganic phosphorus.
• Yttrium-aluminum garnet-based particles for example, YAG: Ce
• aluminum-terbium garnet-based particles for example, TAG, (for example, TAG: Ce)
• silicate-based particles for example, SrBaSi04: Eu
• particles based on sulphides eg SrGa2S4: Eu, SrS: Eu, CaS: Eu, etc.
• nitride-based particles eg, Sr2Si5N8: Eu, Ba2Si5N8: Eu, etc.
• oxynitride-based particles eg Ca-a-SiAION: Eu, SrSi202N2: Eu, etc.
• fluoride-based particles eg, K 2 SiF6: Mn, Na2SiF6: Mn, etc.
• K 2 SiF6: Mn, Na2SiF6: Mn, etc. are examples of inorganic phosphors.
• conversion materials such as doped aluminates, doped nitrides, doped fluorides, doped sulfides, or doped silicates.
• the conversion material is, for example, doped with rare earth elements, alkaline earth metal elements or transition metal elements.
• Cerium is, for example, sometimes used for doping yttrium-aluminum garnets.
• the light converter comprises, for example, a set of particles P made of the conversion material. These P particles are sometimes called "phosphors".
• the substrate 12 is configured to carry each light emitter 10.
• the substrate 12 is, for example, plane. In particular, the substrate 12 extends in a plane perpendicular to a normal direction N.
• the substrate 12 has a third face 25.
• the first face 20 is a face of the substrate 12.
• the substrate 12 is delimited in the normal direction N by the first face 20 and by the third face 25.
• Each of the first face 20 and of the third face 25 is, for example, planar.
• the substrate 12 is, for example, made at least partially of an electrically insulating material.
• the electrically insulating material is, for example, Al203, SiN, or even SiC> 2.
• Each light emitter 10 comprises an emitting structure 30, a first contact 35 and a second contact 40.
• Each emitting structure 30 is carried by the third face 25.
• each emitting structure 30 extends from the third face 25 in the normal direction N.
• the emitting structures 30 of the different light emitters 10 form, for example, a two-dimensional network in a plane perpendicular to the normal direction N, for example a square mesh network.
• the mesh is hexagonal, triangular, or even rectangular.
• Each emitter structure 30 is, for example, a semiconductor structure.
• semiconductor structure is understood to mean any structure made up at least partially of a semiconductor material.
• a stack of semiconductor layers stacked along the normal direction N is an example of a semiconductor structure.
• Such a structure is often referred to as a "two-dimensional structure”.
• a three-dimensional semiconductor structure or a set of three-dimensional semiconductor structures are other examples of semiconductor structures.
• a lateral dimension is defined for each emitting structure 30.
• the lateral dimension is the maximum dimension of an outline surrounding the emitting structure 30 in a plane perpendicular to the normal direction N, while not surrounding any part of another emitting structure. 30.
• the lateral dimension is less than or equal to 20 microns ( ⁇ m).
• the lateral dimension is less than or equal to 10 ⁇ m. In one embodiment, the lateral dimension is less than or equal to 5 ⁇ m.
• Each emitting structure 30 is configured to emit the first radiation from the light emitter 10 containing the emitting structure 30.
• each emitting structure is an LED structure.
• each emitting structure 30 is configured to emit the first radiation when the emitting structure 30 is traversed by an electric current, as will be explained in more detail below.
• FIG. 1 An example of a light emitter 10 comprising an emitting structure 30 is shown in Figure 2.
• the emitting structure 30 is, for example, a three-dimensional semiconductor structure. It should be noted that in possible variants, the emitting structure 30 is a two-dimensional structure.
• the light emitter 10 comprises a plurality of three-dimensional emitting structures 30, these emitting structures 30 being in particular identical to each other.
• the emitting structure 30 extends from the third face 25 along the normal N direction.
• the emitting structure 30 is, for example, a microfilament.
• the emitting structure 30 includes a core 45 and a cover layer 50.
• Core 45 acts as either an n-doped layer or a p-doped layer.
• the core 45 is made of a semiconductor material referred to as "core semiconductor material" in the following.
• the core semiconductor material is n doped.
• the core semiconductor material is, for example, GaN.
• Core 45 is configured to support cover layer 50.
• Core 45 extends from third face 25 along the normal direction N. In particular, core 45 is electrically connected to substrate 12.
• the core 45 extends, for example, through an electrically insulating layer 55 covering part of the third face 25.
• the core 45 is, for example, a cylinder.
• a cylindrical surface is a surface made up of all points on all lines that are parallel to a line and that pass through a fixed planar curve in a plane that is not parallel to the line.
• a solid bounded by a cylindrical surface and two parallel planes is called a "cylinder".
• a cylinder has a uniform cross section along the direction in which the cylinder extends.
• the cross section of the core 45 is polygonal.
• the cross section is hexagonal.
• the shape of the core 45 may vary, for example if the emitting structure 30 is not a microfilament.
• a diameter is defined for the core 45.
• the diameter is, in the case of a cylindrical core 45, the maximum distance between two points of the core 45 which are diametrically opposed in a plane perpendicular to the normal direction N.
• the diameter of the core is measured between two opposite angles of the hexagon.
• the diameter of the core 45 is between 10 nm and 5 ⁇ m.
• a length measured along the normal direction N is defined for the core 45.
• the length is between 10 nm and 100 ⁇ m.
• the core 45 has an upper face and a side face.
• the upper face delimits the core 45 along the normal direction N.
• the upper face is perpendicular to the normal direction N.
• the lateral face surrounds the core 45 in a plane perpendicular to the normal direction N.
• the side face extends between the top face and the substrate 12.
• the side face has a set of plane facets.
• the cover layer 50 at least partially covers the core 45.
• the cover layer 50 at least partially covers the upper face. of the nucleus.
• the cover layer 50 completely covers the upper face.
• the cover layer 50 at least partially covers the upper face and at least partially the side face.
• the cover layer 50 completely surrounds the core 45 in a plane perpendicular to the normal direction N. In other words, the cover layer 50 forms a shell around the core 45.
• the cover layer 50 comprises at least an emitting layer 60 and a doped layer 65.
• Each emitting layer 60 is configured to emit the first radiation when electric current passes through the emitting structure 30.
• Each emitting layer 60 is interposed between the core 45 and the doped layer 65.
• Each emitting layer 60 is made of a semiconductor material.
• the cover layer 50 comprises a stack of emitting layers 60 interposed between the core 45 and the doped layer 65.
• Each emitting layer 60 is, for example, a quantum well.
• the thickness of each emitting layer 60 is, at any point of the emitting layer 60, between 1 nm and 200 nm.
• these emitting layers are, in particular, separated from each other by semiconductor barrier layers, each barrier layer having a band gap value strictly greater than the band gap value of the emitting layers between which the barrier layer is interposed.
• each emitting layer 60 is measured, at any point of the emitting layer 60, along a direction perpendicular to the surface of the core 45 at the point on the surface of the core 45 which is closest to the point of the emitting layer 60 considered.
• each emitting layer 60 at a point on the emitting layer 60 that is aligned with a point on the core 45 along the normal direction N is measured along the normal direction N.
• the thickness of each emitter layer 60 at a point of emitter layer 60 that is aligned in a plane perpendicular to the direction normal with a point of core 45 is measured along a direction perpendicular to the facet closest to core 45.
• Each emitting layer 60 is, for example, made of InGaN.
• the doped layer 65 at least partially covers the emitting layer (s)
• the doped layer 65 is made of a semiconductor material.
• the doped layer 65 acts as an n-doped layer or a p-doped layer of the LED structure.
• the doping type (n or p) of the doped layer 65 is opposed to the type of doping (p or n) in the core 45.
• the doped layer 65 is p doped.
• the doped layer 65 is, for example, made of GaN.
• first face 20 is used to designate the face of the plate 11 which carries the first contacts 35.
• each first contact 35 is placed opposite the emitting structure 30 belonging to the same light emitter 10 as the first contact 35.
• the first contact 35 is aligned with the emitting structure 30 in the normal direction N.
• the first contacts 35 form a two-dimensional network on the first face 20, as visible in FIG. 3.
• the first contacts 35 form a two-dimensional square mesh network.
• the mesh is hexagonal, triangular, or even rectangular.
• first contacts 35 are arranged along a set of clean lines LP, each clean line LP extending in a first direction D1.
• the first direction D1 is, in particular, common to all the LP own lines.
• the clean lines LP are offset with respect to each other in a second direction D2.
• the second direction D2 is perpendicular to the first direction D1.
• Each first contact 35 is electrically connected to the corresponding transmitter structure 30.
• the first contact 35 is electrically connected to the emitting structure 30 by an electrical conductor 70 received in a conduit passing through the substrate 12 in the normal direction N.
• each first contact 35 is electrically connected to a cathode of the emitting structure 30.
• each first contact 35 is electrically connected to an n-doped zone of the emitting structure 30, in particular to the core 45.
• each first contact 35 is electrically connected to an anode of the emitting structure 30.
• each first contact 35 is electrically. connected to a p-doped zone of the emitting structure 30, in particular to the doped layer 65.
• Each first contact 35 is electrically isolated from the other first contacts 35.
• a distance, in a plane perpendicular to the normal direction N, between two neighboring first contacts 35 is between 0.5 ⁇ m and 1 millimeter (mm).
• a coverage rate of the first face 20 by the first contacts 35 is defined.
• the coverage rate is the ratio between, in the numerator, the total area of the first contacts 35 and, in the denominator, the area of a portion of the first face 20 delimited by a closed contour surrounding each first contact 35 in a plane perpendicular to the normal direction N and tangent to the first contacts 35 which are arranged on a perimeter of all of the first contacts 35.
• the coverage rate is between 1% and 99%.
• the coverage rate is between 15% and 80%.
• Each first contact 35 is made of an electrically conductive material.
• each first contact 35 is, for example, made of a material suitable for reflecting the first radiation.
• each first contact 35 is made of a metallic material.
• each first contact 35 is made of aluminum.
• other electrically conductive materials are likely to be considered, including silver, copper, gold, titanium, nickel, tantalum and tungsten.
• each first contact 35 is in the shape of an irregular pentagon. It should be noted that the shape of the first contacts 35 may vary.
• Each first contact 35 has a thickness, measured in the normal direction N, of between 50 nm and 100 ⁇ m.
• Each second contact 40 is, for example, disposed on the first face 20.
• the second contact is disposed on the third face 25.
• Each second contact 40 is configured so that when an electric potential difference is applied between the first contact 35 and the second contact 40, an electric current passes through the emitting structure 30.
• the electric current passes through the core 45, the or the emitting layer (s) 60 and the doped layer 65.
• Each second contact 40 is, for example electrically connected to the cover layer 50, in particular to the doped layer 65. In this case, the second contact 40 is electrically connected to an anode of the emitting structure 30.
• each second contact 40 is electrically connected to the cover layer 50 by a connection layer 72.
• the connection layer 72 is made of an electrically conductive material.
• the connection layer 72 is made of a transparent material.
• the connection layer 72 is made of indium tin oxide (also called ITO).
• ITO indium tin oxide
• the connection layer 72 covers, for example, at least partially the cover layer 50 and the insulating layer 55 and is electrically connected to the second contact 40 through the substrate 12.
• the connection layer 72 has, for example, a thickness of between 10 nm and 2 ⁇ m.
• the second contact 40 is, for example, common to each of the light emitters 10 of the same pixel 15, as visible in FIG. 3.
• each second contact 40 is placed between the four first contacts 35 corresponding to four emitters. light 10 of the same pixel 15.
• the location of the second contact 40 relative to the first contacts 35 is likely to vary.
• the second contact 40 is common to each of the light emitters 10 of the set of light emitters 10.
• the set of light emitters 10 comprises, for example, a single second contact. 40.
• each light emitter 10 comprises a second contact 40 distinct from the second contacts 40 of the other light emitters 10.
• Each second contact 40 is, for example, electrically connected to each other second contact 40 of the assembly of. light emitters 10.
• the connection layer 72 is common to each of the light emitters 10 of the set of light emitters 10.
• the connection layer 72 covers the entire insulating layer 55. and the entirety of each cover layer 50.
• the connection layer 72 is, in particular, a conformal layer deposited on the emitting structures 30 and the insulating layer 55 after the manufacture of the emitting structures 30 and of the insulating layer. 55.
• Each second contact 40 is made of an electrically conductive material, for example of a metallic material.
• each second contact 40 is made of aluminum.
• other electrically conductive materials are likely to be considered, including silver, gold, titanium, copper, nickel, tantalum and tungsten.
• each second contact 40 is made of the same material (s) as each first contact 35.
• each light emitter 10 comprises, for example, a layer 75, each emitting structure 30 being embedded in the layer 75.
• each connection layer 72 is interposed between layer 75 and substrate 12, and between emitting structure 30 and layer 75.
• Layer 75 is made of an electrically insulating material such as, for example, SiN or Si0.
• Layer 75 has, in particular, a height greater than or equal to the height of each emitting structure 30, measured in the normal direction N.
• the second face 22 is, for example, one face of the layer 75.
• the layer 75 is then delimited in the normal direction N by the second and third faces 22 and 25.
• FIG. 4 represents a flowchart of the steps of this manufacturing process.
• the method comprises a supply step 100 and a manufacturing step 110.
• the substrate 12 and the emitting structures 30 carried by the substrate 12 are supplied.
• the substrate 12, carrying the electrically insulating layer 55 is inserted into a material deposition chamber, and the emitting structures 30 are formed on the substrate 12 by material deposition techniques.
• the substrate 12 is provided in the form of a plate supporting the electrically insulating layer 55, the emitting structures 30 and, optionally, the layer 75, then being formed on the third face 25, then the substrate 12 is refined so as to reveal the first face 20.
• the substrate 12 has, after refining, a thickness of between 100 nm and 1 mm.
• the refining is, in particular, carried out via a mechanical or mechanochemical polishing method, or even by reactive ionic etching.
• the electrically insulating layer 55 has, in particular, a set of holes through which the third face 25 is visible, and intended to allow the formation of the cores 45 on the third face 25 while preventing the growth of the material constituting the core on the layer. electrically insulating 55.
• each core 45 is formed, the emitting layer (s) 60 and the doped layer 65 then being formed on the core 45.
• vapor deposition by an organometallic chemical process is a means of obtaining emitting structures 30.
• this means makes it possible to obtain cores 45 of microwires, in particular when the material is selectively deposited in the holes of the electrically insulating layer 55.
• MOCVD deposition is also called “MOVPE”, which means “vapor phase epitaxy by organometallic chemical process”.
• CVD chemical vapor deposition
• MBE molecular beam epitaxy
• GSMBE gas source MBE
• MOMBE organometallic molecular beam epitaxy
• PAMBE assisted plasma
• ALE atomic layer epitaxy
• HVPE hydride vapor phase epitaxy
• the first contacts 35 and the second contacts 40 are manufactured.
• the manufacturing step 110 includes a forming step 120, a first injection step 130, a first observation step 140, and a removal step 150.
• the manufacturing step 110 further comprises a second injection step 160 and a second observation step 170.
• each first contact 35 is formed on the first face 20.
• each second contact 40 is further formed on the first face 20.
• At least a first conductor 80A is formed on the first face 20, for example a set of first conductors 80A.
• at least a first connection pad 82A is also formed.
• a third contact 85 is further formed.
• Each first contact 35 is, for example, formed by depositing, on the first face 20, one or more electrically conductive layers 87 superimposed in the normal direction N.
• each first contact 35, each first conductor 80A, and, optionally, each second contact 40, each third contact 85 and / or the first connection pad 82A are formed by depositing this or these electrically conductive layer or layers 87.
• Each electrically conductive layer 87 is made of the electrically conductive material (s) intended to form each first contact 35, each first conductor 80A, and, optionally, each second contact 40, each third contact 85 and / or the first connection pad 82A.
• the electrically conductive layer or layers 87 are deposited by a vacuum deposition technique, for example by vacuum evaporation.
• the manufacturing step 120 comprises the deposition, on the first face 20, of a first mask at least partially covering the first face 20, and delimiting a set of visible portions of the first face 20.
• the material or materials intended to form each first contact 35, each first conductor 80A and, optionally, each second contact 40, the third contact 85 and / or the first connection pad 82A, are then deposited on the first mask and on the visible portions.
• the first mask is then removed, for example by plasma etching or by chemical dissolution in a solvent bath.
• the materials deposited on the visible portions form at least each first contact 35, each first conductor 80A and, optionally, each second contact 40, the third contact 85 and / or the first connection pad 82A, while that the materials deposited on the first mask are removed with the first mask.
• each first contact 35, each first conductor 80A, and, optionally, each second contact 40, the third contact 85 and / or the first connection pad 82A has a thickness common to each first contact 35, each first conductor 80A, and, optionally, at each second contact 40, at the third contact 85 and / or the first connection pad 82A.
• first contacts 35 formed at the end of the forming step 120, a first set of first contacts 35.
• first set is formed by each of the first contacts 35 which is. electrically connected to a first electrical conductor 80A.
• the first set includes at least two of the first contacts 35. According to the example of Figure 6, each of the first contacts 35 belongs to the first set.
• the first contacts 35 of the first set are distributed into a plurality of first sub-assemblies 90.
• each first sub-assembly 90 groups together all the first contacts 35 which are arranged along the same specific line LP.
• a first sub-assembly 90 is in particular identified in FIG. 6 by a dotted frame.
• the first electrical conductors 80A electrically connect the first contacts 35 of the first set to each other.
• the set of first electrical conductors 80A is configured to transmit an electrical current from each first contact 35 of the first set to each other first contact 35 of the first set.
• Each first electrical conductor 80A extends, for example, between two first contacts 35 of the first set. According to one embodiment, at least a first electrical conductor 80A extends between a first contact 35 of the first set and the first connection pad 82A.
• first electrical conductor 80A is in contact with these two elements and is configured to carry an electric current between these two elements.
• each first contact 35 of the first set is electrically connected to at least one other first contact 35 of the same first sub-assembly 90 by one or more first electrical conductors 80A.
• a first electrical conductor 80A extends between each first contact 35 of the first set and each first contact 35 belonging to the same first sub-assembly 90 and adjacent to the first contact 35 considered.
• each first contact 35 is electrically connected by the first electrical conductors 80A to each other first contact 35 of the same first sub-assembly 90, either directly by a first electrical conductor 80A extending between the two first contacts 35 considered, or via one or a plurality of first contact (s) 35 and the first conductor (s) 80A which extends between these first contacts 35.
• Each first electrical conductor 80A extends in an extension direction, which is for example the first direction D1, between two first contacts 35 of the first set.
• the first electrical conductor 80A has a width, measured in a direction perpendicular to the normal direction N and to the direction of extension, of between 50 nm and 100 ⁇ m.
• the first connection area 82A is carried by the first face 20.
• the first connection area 82A is electrically isolated from each second contact 40.
• the first connection pad 82A is electrically connected to each first contact 35 of the first set.
• the first connection pad 82A is electrically connected to a first contact 35 of each first sub-assembly 90 by a first conductor 80A which extends between the first connection pad 82 and this first contact 35. Since each first contact 35 of each first sub-assembly 90 is electrically connected to the other first contacts 35 of the same first sub-assembly 90 by first conductors 80A, the first connection pad 82A is electrically connected to each first contact 35 of the first assembly.
• each first contact 35 of the first set is electrically connected to each other first contact 35 of the first set by the first conductors 80A, where appropriate via one or a plurality of other first contacts 35 and / or via the first connection pad 82A.
• each first conductor 80A extends in the first direction D1 from the first connection area 82, and is interposed in the second direction D2 between two rows of first contacts 35, each row extending in the first direction D1. The first conductor 80A is then connected to each of the first contacts 35 of these two rows.
• the first connection area 82A is provided to allow a power source to be connected to each of the first contacts 35 of the first set via the first conductor (s) 80A.
• the first connection area 82A has an area of between 10 ⁇ m 2 ... and 10 mm 2 .
• the third electrical contact 85 is configured so that an electrical current flowing between the third electrical contact 85 and each first contact 35 passes through the emitting structure 30 corresponding to the first contact 35 considered.
• the third electrical contact 85 is electrically connected to the connection layer 72.
• the third electrical contact 85 is electrically connected to each second contact 40.
• the third contact 85 is carried by the first face 20.
• the third contact 85 is electrically connected to the doped layer 65 of each light emitter 10.
• the third contact 85 extends through the substrate 12 and, optionally, through the electrically insulating layer 55, between the first face 20 and the layer 75.
• the third contact 85 is connected to the bonding layer 72 and the first bonding pad 82A is connected to each first contact 35, the third contact 85 and the first bonding pad 82A, together, provide power to each transmitter of the transmitter. light 10.
• the first connection pad 82 A and the third contact 85 together, surround the first set of first contacts 35.
• the third contact 85, the first set of first contacts 35 and the first connection place 82A are aligned in this order in the first direction D1.
• a first electric current is injected through each first contact 35 of the first set.
• a power supply source is electrically connected to the first connection pad 82A and to the third contact 85 so as to generate a potential difference between the first connection pad 82A and the third contact 85.
• the potential difference is generated between the first connection pad 82A and one or a plurality of second contact (s) 40. This is in particular the case when each second contact 40 is electrically. connected to each of the other second contacts 40, for example via the connection layer 72.
• one of the second contacts 40 is electrically connected to the electrical source.
• the potential difference is greater than or equal to 3.5 volts (V).
• Each first electric current passes successively through the first connection pad 82, at least a first conductor 80A, the first contact 35 considered and the emitting structure 30 associated with this first contact 35.
• the first electric current also passes through at least one. another first contact 35 and at least one other first conductor 80A which form part of an electrically conductive path connecting the first connection pad 82A to said first contact 35.
• each first contact 35 of the first set and the emitting structure 30 associated with this first contact 35 are each traversed by the corresponding first current.
• Each first current is a current intended to cause the emission of the first radiation by the emitting structure 30 through which this first current passes.
• the first current has an intensity.
• the intensity is, in particular, such that each emitting structure 30 is crossed by a current density greater than or equal to 0.05 amperes per square centimeter (A / cm 2 ).
• the intensity is modified during the first injection step.
• the intensity is increased from a first value to a second value.
• the first value is, for example, a nominal value at which each emitting structure 30 is intended to emit the first radiation.
• the first value corresponds, for example, to a current density of between 0.05 A / cm 2 and 1 A / cm 2 .
• the second value is strictly greater than the first value, for example, greater than or equal to 105 percent (%) of the first value.
• the emitting structure 30 of at least one light emitter 10 is capable of emitting the corresponding first radiation.
• each emitting structure 30 emits the corresponding first radiation.
• At least one emitting structure 30 connected to a first contact 35 of the first set does not emit the first radiation, or emits a first radiation having a very low light intensity compared to the light intensity of the other emitting structures.
• Such an emitting structure 30 is considered to be defective.
• each first emitted radiation passes through the substrate 12 in the normal direction N and passes through the first face 20.
• at least part of this first radiation passes through the first face 20 and leaves the substrate 12 via a portion of the first face 20 which does not include any electrically conductive layer such as in particular the conductive layers 87 which form the first contacts 35 and the first conductors 80A.
• the first conductors 80A and the first contacts 35 are configured to allow at least part of the first radiation to pass through the first face 20.
• the rate of coverage of the first face 20 by the first contacts 35 and by the first conductors 80A is in particular strictly less than 100%.
• the first observation step 140 part of the first radiation is observed through the first face 20.
• the first observation step 140 is therefore carried out simultaneously with the first injection step 130.
• an imager is placed opposite the first face 20 and acquires an image of the first face 20 when the first currents are injected through the first contacts 35.
• the imager measures a spatial variation, on the first face 20, of a light intensity of the first observed radiation. For example, it is measured, for each first contact 35 of the first set, a total light intensity of a zone of the first face 20 centered on the first contact 35 considered.
• the observation step 140 comprises, for example, the detection of a defective transmitter structure 30. For example, the light intensity of each zone is compared to a predetermined threshold, and it is determined that an emitting structure 30 is defective when the light intensity of the area centered on the first contact 35 of the emitting structure 30 is lower. or equal to the threshold.
• a variation in the light intensity along a clean line LP, or even along a straight segment parallel to the second direction D2 is another method of observing the first radiation making it possible to detect a faulty transmitter structure 30.
• the first range of wavelengths associated with the first radiation observed in the zone centered on each first contact 35 is determined. For example, a spectral study is performed in which the light intensity as a function of wavelength or photon energy is measured.
• each first conductor 80A is removed.
• each first conductor 80A is removed by etching.
• Etching consists of exposing each first conductor 80A to a fluid such as a gas, a liquid, or even a plasma, so as to remove the material (s) making up the first conductor 80A.
• each first conductor 80A that is to say the layer or layers 87 deposited during the forming step 120, are removed by etching.
• Etching is, for example, plasma etching, or even wet chemical etching through a lithography mask.
• a second mask for example made of a photosensitive resin, is deposited on the first face 20.
• the second mask covers each first contact 35, and does not cover the first conductors 80A.
• the first face 20 covered with the mask is exposed to the fluid so as to remove the exposed materials and to leave the materials unchanged, in particular the first contacts 35, protected by the second mask.
• the emitting structures 30 of the first set are electrically connected in a simple manner to an electrical source since the associated first contacts 35 are electrically connected to each other.
• a respective connector such as a wire or a tip.
• a single such connector is sufficient, in contact with one of these first contacts 35, with one of the first conductors 80A or with the first contact pad 82A, to inject an electric current into each of the emitting structures 30 of the device. first set.
• the light emitter assembly 10 is attached to a retainer so as to leave the first face 20 exposed to allow the deposition of the first contacts 35, so that the third face 25 , which is designed to allow radiation to pass during nominal operation of the light emitters 10, is not accessible.
• the fact of observing the first radiation through the first face 20 then makes it possible to avoid having to unhook the entire holding device in order to observe the third face 25, which again makes the process faster.
• the etching makes it possible to simply remove each of the first conductors 80A. It suffices in fact to design a second mask adapted to reveal each of the first conductors 80A and to cover each of the first contacts 35.
• Measuring the light intensity of the area centered on a first contact 35 is a simple method of detecting a defective emitting structure 30.
• At least a second set of first contacts 35, separate from the first set, is also defined.
• a set of second conductors 80B is formed on the first face 20, and, optionally, a second contact pad 82B is formed on the first face 20.
• the second conductors 80B and, optionally the second contact pad 82B are in particular produced simultaneously with the first conductors 80A via the deposition of one or more layers 87 of the same material or materials.
• the second group includes all the first contacts 35 which are interconnected by second conductors 80B.
• the second set includes at least two of the first contacts 35. It is understood by “disjoint” that no first contact 35 jointly belongs to the first. together and to the second set. Thus, no first contact 35 is electrically connected to a first conductor 80A and to a second conductor 80B. As a result, the first and second sets are electrically isolated from each other.
• each first contact 35 belongs to the first set or to the second set.
• a number of first contacts 35 in the first set is the same as a number of first contacts 35 in the second set.
• Each first contact 35 of the second set is electrically isolated from each first contact 35 of the first set.
• the first contacts 35 of the second set are distributed into a plurality of second sub-assemblies 95.
• each second sub-assembly 95 groups together all the first contacts 35 which are arranged along the same specific line LP.
• a second sub-assembly 95 is in particular identified in FIG. 7 by a dotted frame.
• the clean lines LP of the first are-assemblies 90 and of the second sub-assemblies 95 are alternated in the second direction D2.
• a single first sub-assembly 90 is interposed between each pair of second successive second sub-assemblies 95
• a single second sub-assembly 95 is interposed between each pair of successive first sub-assemblies 95.
• the second electrical conductors 80B electrically connect the first contacts 35 of the second set to each other.
• the set of second electrical conductors 80B is configured to transmit an electrical current from each first contact 35 of the second set to every other first contact 35 of the second set.
• Each second electrical conductor 80B extends, for example, between two first contacts 35 of the second set. According to one embodiment, at least a second electrical conductor 80B extends between a first contact 35 of the second set and the second connection pad 82B.
• each first contact 35 of the second set is electrically connected to at least one other first contact 35 of the same second sub-assembly 95 by one or more second electrical conductors 80B.
• a second electrical conductor 80B extends between each first contact 35 of the second set and each first contact 35 belonging to the same second sub-assembly 95 and adjacent to the first contact 35 considered.
• each first contact 35 of the second set is electrically connected by the second electrical conductors 80B to each other first contact 35 of the same second sub-assembly 95, either directly via a second electrical conductor 80B extending between the two first contacts 35 considered, or via one or more first contact (s) 35 and the second conductor (s) 80B which extends between these first contacts 35.
• Each second electrical conductor 80B extends in an extension direction, which is for example the first direction D1.
• the second electrical conductor 80B has a width, measured in a direction perpendicular to the normal direction N and to the direction of extension, between 50 nm and 1 mm.
• the second connection area 82B is carried by the first face 20.
• the second connection pad 82B is electrically connected to each first contact 35 of the second set.
• the second connection pad 82B is electrically connected to a first contact 35 of each second sub-assembly 95 by a second conductor 80B which extends between the second connection pad 82 and this first contact 35. Since each first contact 35 of each second sub-assembly 95 is electrically connected to the other first contacts 35 of the same second sub-assembly 95 by second conductors 80B, the second connection pad 82B is electrically connected to each first contact 35 of the second assembly.
• each first contact 35 of the second set is electrically connected to each other first contact 35 of the second set by the second conductors 80B, where appropriate via one or a plurality of other first contacts 35 and / or via the second connection pad. 82B.
• each first contact 35 is interposed in the first direction D1 between the first connection area 82A and the second connection area 82B.
• the second connection pad 82B is provided to allow a power source to be connected to each of the first contacts 35 of the second set via the second conductor (s) 80B.
• the first connection pad 82B has an area of between 10 ⁇ m 2 and 10 mm 2 .
• the method includes a second injection step 160 and a second observation step 170.
• a second electric current is injected through each first contact 35 of the second set.
• the second injection step 160 is offset in time with respect to the first injection step 130.
• no second current is injected simultaneously with a first current.
• a power supply source is electrically connected to the second connection pad 82B and to the third contact 85 so as to generate a potential difference between the second connection pad 82B and the third contact 85.
• the potential difference is greater than or equal to 3.5 V.
• Each second electric current passes successively through the second connection pad 82B, at least one second conductor 80B, the first contact 35 considered and the emitting structure 30 associated with this first contact 35.
• the first electric current also passes through at least one. another first contact 35 and at least one other second conductor 80B which form part of an electrically conductive path connecting the second connection pad 82B to said first contact 35.
• each first contact 35 of the second set and the emitting structure 30 associated with this first contact 35 are each traversed by the corresponding second current.
• Each second current is a current intended to cause the emission of the first radiation by the emitting structure 30 through which this second current passes.
• the second current has an intensity.
• the intensity corresponds to a current density greater than or equal to 0.05 A / cm 2 .
• the intensity is modified during the second injection step 160.
• the intensity is increased from a first value to a second value.
• the emitting structure 30 of at least one light emitter 10 of the second set is capable of emitting the corresponding first radiation.
• each emitting structure 30 emits the corresponding first radiation.
• some emitting structures 30 are also likely to be defective and not emit the first radiation.
• the first radiations emitted by the emitting structures 30 of the light emitters of the first set at least partially pass through the first face 20.
• the second observation step 170 is therefore carried out simultaneously with the second injection step 160.
• a defective emitting structure 30 is detected when a total light intensity of a zone of the first face 20 centered on the first contact 35 considered is less than or equal to the threshold.
• each second conductor 80B is withdrawn simultaneously with the first conductors 80A.
• the use of two sets of distinct first contacts 35 during the manufacturing step 110 makes it possible, during the injection 130, 160 and observation steps 140, 170, to supply only a part of the first contacts 35. , and therefore emitting structures 30, at the same time.
• each first or second sub-assembly 90, 95 groups together the first contacts 35 arranged along the same specific line, these first or second sub-assemblies being alternated in the second direction D2, makes it possible to effectively detect a defective emitting structure, since this emitting structure 30 is surrounded, in the second direction D2, by two emitting structures 30 which are not supplied with power.
• first contacts 35 are interposed between the two connection pads 82A and 82B, it is particularly easy to manufacture the first and second assemblies.
• connection pads 82A, 82B to inject the first and / or second currents makes it possible to avoid damaging the first contacts 35 during these steps by applying a tip or a connection terminal to the power source. The subsequent contact between the first contacts 35 and the control circuit is then improved and the reliability of the screen obtained is improved.
• each injection step 130, 160 is carried out with only two electrical connections, and is therefore particularly easy to carry out.
• the observation of the radiation emitted through the first face makes it possible in particular to carry out the observation while the plate 11 and the assembly of light emitters 10 that it carries are attached to a handle limiting access to the second face 22.
• each first sub-assembly 90 comprises each of the first contacts 35 which extend along two adjacent LP clean lines.
• Each first conductor 80A extends between the two clean lines LP of a corresponding first sub-assembly 90 and is connected to each of the first contacts 35 arranged along these two clean lines.
• each second sub-assembly 95 comprises each of the first contacts 35 which extend along two neighboring LP clean lines.
• Each second conductor 80B extends between the two clean lines LP of a corresponding second sub-assembly 95 and is connected to each of the first contacts 35 arranged along these two clean lines.
• first and second contacts 35, 40 on the first face 20 is liable to vary.
• the first and second contacts 35, 40 form a square mesh network in which a pattern is repeated on the first face 20, each pattern comprising three first contacts 35 and a second contact 40 each arranged at a vertex of a square. It should be noted that other configurations are still possible.
• each first contact 35 is connected to the anode of the corresponding emitting structure 30, as shown in Figure 9.
• each first contact 35 is carried by the layer 75 and connected to the doped layer 65 of the corresponding emitting structure 30.
• the first contact 35 is in contact with a portion of the doped layer 65 which is aligned with the core 45 in the normal direction N.
• the first face 20 is one face of the layer 75.
• the layer 75 is delimited by the first face 20 and by the third face 25.
• the substrate 12 is then delimited in the normal direction N by the second face 22 and by the third face 25.
• the coverage rate of the first contacts 35 is, for example, between 1% and 99%.
• each second contact 40 is then, for example, carried by the second face 22.
• each second contact 40 is common to each light emitter 10.
• the second contact 40 is a layer covering the second face 22 and electrically. connected to the n-doped layer (s) of each emitting structure 30.
• Each second contact 40 is, for example, made of aluminum.
• the first contacts 35 are in particular connected to each other by first or second conductors 80A, 80B each extending in the first direction D1, as shown in FIG. 10.
• emitting structures 30 have been described in the previous examples as being three-dimensional emitting structures, in particular microwires, other types of emitting structures 30 are likely to be envisaged.
• each emitting structure is a two-dimensional structure formed by a stack of layers carried by the substrate 12.
• each layer extends in a plane perpendicular to the normal direction N.
• the layers are common to each issuing structure 30.
• first and second sub-assemblies 90, 95 have been described in the case of a two-dimensional square mesh network formed by the first contacts 35. It should be noted that these sub-assemblies are also capable of being alternated. in the second direction D2 in the case of networks having a non-square mesh, for example a triangular, hexagonal, or even rectangular mesh.
• each of the methods described above is capable of being implemented during a method of producing a display screen comprising a step of supplying a control circuit, a step of setting up a display screen. implementation of the manufacturing process, a separation step, a disposal step, and a connection step.
• the display screen comprises a plurality of light emitters 10, for example grouped together in the form of pixels 15.
• a control circuit for selectively powering a plurality of light emitters 10 is provided.
• At least one light emitter 10 of the manufactured assembly is separated from at least one other light emitter 10.
• the plate 11 is cut to separate at least one light emitter 10. of at least one other light emitter 10, for example of every other light emitter 10.
• the light emitters 10 of the assembly are separated from each other so that each light emitter 10 is mechanically independent of each other light emitter 10.
• the plate 11 is cut so as to separate the light emitters 10 from each other.
• At least one pixel 15 is separated from at least one other pixel 15.
• the plate 11 is cut to separate at least one pixel 15 from at least one other pixel 15, for example from each other.
• the pixels 15 are separated from each other, for example by cutting the plate 11.
• a pixel 15 separated from at least one other pixel 15 that the light emitters 10 of the pixel 15 considered are mechanically secured to each other but are not mechanically secured to the light emitters 10 of the other. pixel 15. This is for example obtained by cutting the plate 11 around the light emitters 10 of the pixel that it is desired to separate.
• At least one light emitter 10 identified as defective during an observation step 140, 170 is discarded.
• each light emitter 10 identified as defective is discarded.
• each pixel 15 including at least one defective light emitter 10 is discarded.
• each light emitter 10 or pixel 15 discarded is not taken into account for the implementation of the steps subsequent to the discarding step.
• each discarded light emitter 10 or pixel 15 is isolated from non-defective light emitters 10 or pixels 15, discarded, or otherwise destroyed in the discard step.
• the connect step can be carried out after the discard step and is therefore only carried out for light emitters 10 or pixels 15 not discarded.
• At least one non-defective light emitter 10 is selected.
• This light emitter 10 is, in particular, a light emitter 10 which has not been discarded.
• This light emitter 10 is connected to the control circuit during the connection step.
• the first contact 35 and the second contact 40 of the light emitter 10 are each connected, directly or indirectly, to a connection pad of the control circuit so that the control circuit is able to injecting an electric current into the emitting structure 30.
• connection step at least one pixel 15 comprising only non-defective light emitters 10 is selected, each light emitter 10 of the selected pixel (s) 15 being connected to the control circuit during the connection step.
• each of the first and second contacts 35, 40 of the set of non-discarded light emitters 10 is connected to a connection pad of the control circuit.
• the light emitters 10 and / or the pixels 15 selected are connected to the control circuit to obtain a display screen or part of a display screen.
• the second contacts 40 are received inside the substrate 12, in particular interposed between the first face 20 and the second face 22.
• the contacts 35 and 40 are arranged on two levels of metal layers. distinct, the first contacts 35 being arranged on a level of metal layers external to the substrate 12 while the second contacts 40 are placed on a level of metal layers internal to the substrate 12.
• the withdrawal step 150 is not implemented.
• at least two first contacts 35 of two separate light emitters 10 are electrically connected to each other at the end of the implementation of the manufacturing process.
• the light emitters 10 are not separated from each other.
• the second contacts 40 are themselves electrically disconnected from each other and each connected to a separate electrode of the control circuit so as to control the light emitters 10 individually.
• the injection steps 130, 160 and observation 140, 170 are, for example, implemented by a test device comprising the electric power source, the imager and an electronic control module.
• the control module is configured to control the injection by the source of the first current and / or the second current during the injection steps 130 and 160.
• control module is configured to receive from the imager the image (s) acquired during the first observation step 140 and / or the second observation step 170.
• the control module is , in particular, configured to detect, from the image (s) received, at least one transmitting structure 30 defective during the first observation step 140 and / or the second observation step 170 .
• control module is configured to store in a memory, during the first observation step 140 and / or the second observation step 170, at least one item of information relating to the position of each transmitting structure 30. faulty detected.
• the information includes, for example, a set of spatial coordinates of the defective transmitter structure 30.
• the information includes an identifier of the defective sending structure 30, for example a number of the defective sending structure 30.
• the control module comprises, for example, in addition to the memory, a processor capable of executing software instructions stored in the memory to implement the steps of injection 130, 160 and observation 140, 170.
• control module comprises, in addition to the memory, a set of dedicated integrated circuits and / or programmable logic components, this set being suitable for controlling the implementation of the injection 130, 160 and observation 140 steps. , 170.
• connection layer 72 is also possible.
• the fourth contacts 40 are connected to the third contact 85 by a set of conductors made of a metallic material. These conductors are, for example, incorporated into the plate 11 supplied during the supply step 100, or else manufactured on one or the other of the faces 20 and 22 during the manufacturing step 110.
• the radiation emitted during the injection steps 130, 160 is likely to be observed through another face than the first face 20, in particular through the face 25.
• DOPING Doping is defined as the presence, in a material, of impurities providing free charge carriers. Impurities are, for example, atoms of an element which is not naturally present in the material.
• the doping is p-type.
• a layer of gallium nitride, GaN is p-doped by adding magnesium (Mg) atoms.
• the doping is n-type.
• a layer of gallium nitride, GaN is n-doped by adding silicon (Si) atoms.
• An LED structure is a semiconductor structure comprising several semiconductor areas forming a P-N junction and configured to emit light when an electric current flows through the different semiconductor areas.
• a two-dimensional structure comprising an n-doped layer, a p-doped layer and at least one emitting layer is an example of an LED structure.
• each emitting layer is interposed, along the normal direction N, between the n-doped layer and the p-doped layer.
• each emitting layer has a band gap value that is strictly less than the band gap value of the n-doped layer and strictly less than the band gap value of the p-doped layer.
• the n-doped layer and the p-doped layer are GaN layers, and each emitting layer is an InGaN layer.
• the emitting layer is, for example, undoped. In other embodiments, the emitting layer is doped.
• a quantum well constitutes a specific example of an emitting layer having a band gap value less than the band gap values of the n and p doped layers.
• a quantum well is a structure in which quantum confinement occurs, in one direction, for at least one type of charge carriers.
• the effects of quantum confinement occur when the dimension of the structure along this direction becomes comparable to or smaller than the De Broglie wavelength of the carriers, which are generally electrons and / or holes, leading to energy levels called “energy subbands”.
• carriers can exhibit only discrete energy values but are generally able to move within a plane perpendicular to the direction in which confinement occurs.
• the energy values available to carriers, also called “energy levels”, increase as the dimensions of the quantum well decrease along the direction in which confinement occurs.
• the "De Broglie wavelength” is the wavelength of a particle when the particle is considered a wave.
• the De Broglie wavelength of electrons is also called the “electron wavelength”.
• the De Broglie wavelength of a charge carrier depends on the material of which the quantum well is made.
• An emitter layer whose thickness is strictly less than the product of the electronic wavelength of the electrons in the semiconductor material that the emitter layer is made of and five is an example of a quantum well.
• Another example of a quantum well is an emitting layer whose thickness is strictly less than the product of the De Broglie wavelength of excitons in the semiconductor material of which the emitting layer is made and five.
• An exciton is a quasi-particle comprising an electron and a hole.
• a quantum well often has a thickness of between 1 nm and 200 nm.
• band gap value should be understood as the value of the band gap between the valence band and the conduction band of the material.
• the band gap value is, for example, measured in electron volts (eV).
• the valence band is defined as being, among the energy bands that are allowed for the electrons in the material, the band that has the highest energy while being completely filled at a temperature of 20 Kelvin or less ( K).
• a first energy level is defined for each valence band.
• the first energy level is the highest energy level in the valence band.
• the conduction band is defined as being, among the energy bands which are allowed for the electrons in the material, the band which has the lowest energy while not being completely filled at a temperature less than or equal to 20 K.
• a second energy level is defined for each conduction band.
• the second energy level is the highest energy level in the conduction band.
• each band gap value is measured between the first energy level and the second energy level of the material.
• a semiconductor material is a material having a band gap value strictly greater than zero and less than or equal to 6.5 eV.
• a direct bandgap semiconductor is an example of a semiconductor material.
• a material is considered to have a “direct bandgap” when the minimum of the conduction band and the maximum of the valence band correspond to the same value of momentum of charge carriers.
• a material is considered to have an "indirect band gap" when the minimum of the conduction band and the maximum of the valence band correspond to different values of momentum of charge carriers.
• Each semiconductor material can be chosen, for example, from the set formed by semiconductors III-V, in particular nitrides of elements III, semiconductors II-VI, or even semiconductors. IV-IV.
• III-V semiconductors include InAs, GaAs, AlAs and their alloys, InP, GaP, AIP and their alloys, and element III nitrides.
• the II-VI semiconductors include in particular CdTe, HgTe, CdSe, HgSe, and their alloys.
• IV-IV semiconductors include Si, Ge and their alloys in particular.
• a three-dimensional structure is a structure that extends along a main direction.
• the three-dimensional structure has a length measured along the main direction.
• the three-dimensional structure also has a maximum lateral dimension measured along a lateral direction perpendicular to the principal direction, the lateral direction being the direction perpendicular to the principal direction along which the dimension of the structure is greatest.
• the maximum lateral dimension is, for example, less than or equal to 10 micrometers (pm), and the length is greater than or equal to the lateral dimension maximum.
• the maximum lateral dimension is advantageously less than or equal to 2.5 gm.
• the maximum lateral dimension is, in particular, greater than or equal to 10 nm.
• the length is greater than or equal to twice the maximum lateral dimension, for example it is greater than or equal to five times the maximum lateral dimension.
• the main direction is, for example, the normal direction N.
• the length of the three-dimensional structure is called "height" and the maximum dimension of the three-dimensional structure, in a plane perpendicular to the normal direction N, is less or equal to 10 ⁇ m.
• the maximum dimension of the three-dimensional structure, in a plane perpendicular to the normal direction N, is often called "diameter" regardless of the shape of the cross-section of the three-dimensional structure.
• each three-dimensional structure is a microfilament.
• a microfilament is a cylindrical three-dimensional structure.
• the micro-thread is a cylinder extending along the normal direction N.
• the micro-thread is a cylinder with a circular base.
• the diameter of the base of the cylinder is less than or equal to half the length of the microfilament.
• a microfilament whose maximum lateral dimension is less than 1 ⁇ m is called a "nanowire".
• Another example of a three-dimensional structure is a pyramid extending along the normal direction N from substrate 12.
• Another example of a three-dimensional structure is a cone extending along the normal direction N.
• a truncated cone or a truncated pyramid extending along the normal direction N is yet another example of a three-dimensional structure.

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