Method of manufacturing an optoelectronic device

Abstract

This disclosure relates to a method of manufacturing an optoelectronic device (5) comprising an assembly of a light-emitting diode (LED) having a first component and a second component, and a first block (32) made of a first photoluminescent material, each first block covering one of the first components. The method includes forming a layer covering the first and second components, defining a first opening in the layer to expose the first component, filling the first opening with the first material, and performing chemical mechanical polishing to define the first block.

Description

[0001] This patent application claims priority to French patent application FR19 / 11133, which is incorporated herein by reference. Technical Field

[0002] The present invention generally relates to semiconductor elements comprising nanoscale or microscale, particularly micrometer wires or nanowires, or optoelectronic devices having a pyramidal structure, thereby forming light-emitting diodes and photoluminescent blocks covering the light-emitting diodes. Background Technology

[0003] The term "optoelectronic device" is used to refer to a device capable of converting electrical signals into electromagnetic radiation or performing the reverse operation, particularly a device specifically designed for detecting, measuring, or emitting electromagnetic radiation. Electronic devices having three-dimensional semiconductor elements can include light-emitting diodes covered by photoluminescent blocks.

[0004] A method for manufacturing such an optoelectronic device includes forming a light-emitting diode (LED) on a substrate and forming a photoluminescent block covering the LED. The photoluminescent block can be formed by depositing a photoluminescent layer on the LED assembly and etching the photoluminescent layer to define the photoluminescent block.

[0005] Defining a photoluminescent block within a photoluminescent layer can include depositing a resin layer covering the photoluminescent layer, and defining portions of the photoluminescent layer by performing photolithography at desired locations on the photoluminescent block. The photolithography process typically involves detecting visible alignment marks on the substrate to correctly position a mask for exposing the resin layer relative to the light-emitting diode.

[0006] The drawback of this method is that the photoluminescent layer may be opaque to the visible light portion, making it difficult to implement photolithography methods for detecting alignment marks. Summary of the Invention

[0007] Therefore, the objective of the embodiments is to overcome at least some of the disadvantages of the above-described methods for manufacturing optoelectronic devices including light-emitting diodes and photoluminescent blocks.

[0008] Another objective of the embodiments is to have a material that forms a photoluminescent block, which is not a photosensitive material suitable for use in the photolithography step.

[0009] Another objective of the embodiments is to achieve a significant ratio of height to width of the photoluminescent block.

[0010] Another objective of the embodiments is to enable optoelectronic devices to be manufactured on an industrial scale and at low cost.

[0011] One embodiment provides a method of manufacturing an optoelectronic device, the optoelectronic device including an assembly of light-emitting diodes having first and second components, and a first block made of a first photoluminescent material, the first block covering each of the first components. The method includes forming a layer covering the first and second components, defining a first opening in the layer to expose the first components, filling the first opening with the first material, and performing chemical mechanical polishing to define the first block.

[0012] According to one embodiment, the device includes a second block made of a second photoluminescent material different from the first photoluminescent material, each of the second blocks covering one of the second components, the method including defining a second opening in the layer to expose the second component, filling the second opening with the second material, and performing chemical mechanical polishing to define the second block.

[0013] According to one embodiment, the device further includes a third component of a light-emitting diode and a third block made of a third photoluminescent material different from the first and second photoluminescent materials, each of the third blocks covering one of the third components, the method comprising defining a third opening in the layer to expose the third component, filling the third opening with the third material, and performing chemical mechanical polishing to define the third block.

[0014] According to one embodiment, the device further includes a fourth component of a light-emitting diode, and the method includes defining a fourth block in the layer, each of the fourth blocks covering one of the fourth components of the light-emitting diode.

[0015] According to one embodiment, the layer is at least partially transparent to radiation emitted by the light-emitting diode of the fourth component of the light-emitting diode.

[0016] According to one embodiment, the method includes defining a fourth opening in the layer between the components and forming a wall having a reflective side in the fourth opening.

[0017] According to one embodiment, the method includes depositing a reflective coating in the fourth opening and filling the remainder of the fourth opening with a fifth material.

[0018] According to one embodiment, the wall is formed after the first photoluminescent block.

[0019] According to one embodiment, the method includes forming a barrier layer that extends in the fourth opening and covers the first photoluminescent block before forming the wall.

[0020] According to one embodiment, the wall is formed after the first and second photoluminescent blocks.

[0021] According to one embodiment, the wall is formed in front of the first and second photoluminescent blocks.

[0022] According to one embodiment, the method includes etching the layer present between the first, second, and third photoluminescent blocks, forming a barrier layer extending in the fourth opening and covering the first, second, and third photoluminescent blocks before forming the wall, and forming the wall in the space present between the first, second, and third photoluminescent blocks. Attached Figure Description

[0023] The above-described features and advantages, as well as other features and advantages, will be described in detail below with reference to the accompanying drawings, which are given by way of example rather than limitation, in which:

[0024] Figure 1 This is a partially simplified cross-sectional view of an embodiment of an optoelectronic device having a light-emitting diode and a photoluminescent block;

[0025] Figure 2 This is a partial simplified cross-sectional view of an embodiment of a light-emitting diode;

[0026] Figure 3 In manufacturing Figure 1 A cross-sectional view of the structure obtained in the steps of an embodiment of the method for the device;

[0027] Figure 4 It is a cross-sectional view of the structure obtained in another step of the method;

[0028] Figure 5 It is a cross-sectional view of the structure obtained in another step of the method;

[0029] Figure 6 It is a cross-sectional view of the structure obtained in another step of the method;

[0030] Figure 7 It is a cross-sectional view of the structure obtained in another step of the method;

[0031] Figure 8 It is a cross-sectional view of the structure obtained in another step of the method;

[0032] Figure 9 It is a cross-sectional view of the structure obtained in another step of the method;

[0033] Figure 10 It is a cross-sectional view of the structure obtained in another step of the method;

[0034] Figure 11 It is a cross-sectional view of the structure obtained in another step of the method;

[0035] Figure 12 It is a cross-sectional view of the structure obtained in another step of the method;

[0036] Figure 13 It is a cross-sectional view of the structure obtained in another step of the method;

[0037] Figure 14 It is a cross-sectional view of the structure obtained in another step of the method;

[0038] Figure 15 In manufacturing Figure 1 A cross-sectional view of the structure obtained in the steps of another embodiment of the method for the device;

[0039] Figure 16 It is a cross-sectional view of the structure obtained in another step of the method;

[0040] Figure 17 It is a cross-sectional view of the structure obtained in another step of the method;

[0041] Figure 18 It is a cross-sectional view of the structure obtained in another step of the method;

[0042] Figure 19 It is a cross-sectional view of the structure obtained in another step of the method;

[0043] Figure 20 It is a cross-sectional view of the structure obtained in another step of the method;

[0044] Figure 21 It is a cross-sectional view of the structure obtained in another step of the method;

[0045] Figure 22 It is a cross-sectional view of the structure obtained in another step of the method;

[0046] Figure 23 It is a cross-sectional view of the structure obtained in another step of the method;

[0047] Figure 24 It is a cross-sectional view of the structure obtained in another step of the method;

[0048] Figure 25 It is a cross-sectional view of the structure obtained in another step of the method;

[0049] Figure 26 It is a cross-sectional view of the structure obtained in another step of the method;

[0050] Figure 27 It is a cross-sectional view of the structure obtained in another step of the method;

[0051] Figure 28 In manufacturing Figure 1 A cross-sectional view of the structure obtained in the steps of another embodiment of the method for the device;

[0052] Figure 29 It is a cross-sectional view of the structure obtained in another step of the method;

[0053] Figure 30 It is a cross-sectional view of the structure obtained in another step of the method;

[0054] Figure 31 It is a cross-sectional view of the structure obtained in another step of the method;

[0055] Figure 32 In manufacturing Figure 1 A cross-sectional view of the structure obtained in the steps of another embodiment of the method for the device;

[0056] Figure 33 It is a cross-sectional view of the structure obtained in another step of the method;

[0057] Figure 34 It is a cross-sectional view of the structure obtained in another step of the method;

[0058] Figure 35 It is a cross-sectional view of the structure obtained in another step of the method;

[0059] Figure 36 It is a cross-sectional view of the structure obtained in another step of the method;

[0060] Figure 37 It is a cross-sectional view of the structure obtained in another step of the method;

[0061] Figure 38 It is a cross-sectional view of the structure obtained in another step of the method;

[0062] Figure 39 It is a cross-sectional view of the structure obtained in another step of the method;

[0063] Figure 40 In manufacturing Figure 1 A cross-sectional view of the structure obtained in the steps of another embodiment of the method for the device;

[0064] Figure 41 It is a cross-sectional view of the structure obtained in another step of the method;

[0065] Figure 42 It is a cross-sectional view of the structure obtained in another step of the method;

[0066] Figure 43 It is a cross-sectional view of the structure obtained in another step of the method;

[0067] Figure 44 It is a cross-sectional view of the structure obtained in another step of the method;

[0068] Figure 45 It is a cross-sectional view of the structure obtained in another step of the method;

[0069] Figure 46 It is a cross-sectional view of the structure obtained in another step of the method;

[0070] Figure 47 It is a cross-sectional view of the structure obtained in another step of the method;

[0071] Figure 48 It is a cross-sectional view of the structure obtained in another step of the method;

[0072] Figure 49 It is a cross-sectional view of the structure obtained in another step of the method;

[0073] Figure 50 It is a cross-sectional view of the structure obtained in another step of the method;

[0074] Figure 51 It is a cross-sectional view of the structure obtained in another step of the method; and

[0075] Figure 52 This is a cross-sectional view of the structure obtained in another step of the method. Detailed Implementation

[0076] Similar features are indicated by similar reference numerals in the various figures. In particular, common structural and / or functional features in the various embodiments may have the same reference numerals and may have the same structure, dimensions, and material properties. For clarity, only steps and elements useful for understanding the embodiments described herein are described in detail.

[0077] In the following description, when terms defining absolute position, such as "front," "back," "top," "bottom," "left," "right," etc., or terms defining relative position, such as "upper," "lower," "upper part," "lower part," etc., or terms defining direction, such as "horizontal," "vertical," etc., refer to the orientation of the graphic or indicate the optoelectronic device in its normal operating position. Unless otherwise stated, the expressions "approximately," "approximately," "substantially," and "about" indicate a range of 10%, preferably 5%. When the expressions "approximately," "approximately," "substantially," and "about" relate to direction, they indicate a range of 10°, preferably 5°. Furthermore, the terms "insulating" and "conductive" are considered to mean "electrically insulating" and "conductive," respectively.

[0078] The transmittance of a layer corresponds to the ratio of the radiation intensity exiting the layer through the output surface to the radiation intensity entering the layer from the input surface relative to the output surface. In the following description, a layer or film is said to be radiopaque when the transmittance of radiation through it is less than 10%. In the following description, a layer or film is said to be radiopaque when the transmittance of radiation through it is greater than 10%. In the following description, "visible light" refers to electromagnetic radiation with wavelengths in the range of 400 nm to 700 nm.

[0079] In the following description, the oxygen permeability of the membrane or layer at 40°C is less than 1.10-1 cm. 3 / (m 2 When the permeability is *day*atm, the membrane or layer is considered oxygen-impermeable. Oxygen permeability can be measured according to ASTM D3985, entitled "Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor". In the following description, the permeability of the membrane or layer to water at 40°C is less than 1.10. - 1 g / (m 2 When the membrane or layer is impermeable (as of *day), it is considered impermeable. The permeability to water can be measured according to ASTM F1249, entitled "Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor".

[0080] This invention relates to the manufacture of optoelectronic devices including light-emitting diodes formed from nano- or micro-scale three-dimensional elements, particularly micro-wires, nanowires, or pyramidal elements.

[0081] The terms "micron-wire" or "nanowire" refer to a three-dimensional structure of an elongated shape along a preferred direction, having at least two dimensions referred to as sub-dimensions, ranging from 5 nm to 5 μm, preferably from 100 nm to 2 μm, more preferably from 200 nm to 1.5 μm, and a third dimension referred to as the principal dimension or height, greater than or equal to 1 times the largest sub-dimension, preferably greater than or equal to 3 times, more preferably greater than or equal to 5 times. In some embodiments, the height of each micron-wire or nanowire may be greater than or equal to 500 nm, preferably in the range of 1 μm to 50 μm. In the following description, the term "wire" is used to denote "micron-wire" or "nanowire".

[0082] The cross-section of a line can have different shapes, such as ellipse, circle, or polygon, especially triangle, rectangle, square, or hexagon. The term "average diameter" associated with the cross-section of a line refers to a quantity in that cross-section that relates to the surface area of ​​the line, such as the diameter of a disk that has the same surface area as the cross-section of the line.

[0083] In the following description, the term "pyramid" refers to a three-dimensional structure in which a portion has the shape of a pyramid or an elongated cone. The pyramidal structure may be truncated, with the apex of the cone missing and replaced by a flat area. A square is inscribed in the base of the pyramid, with a side dimension of 100 nm to 10 μm, preferably 0.2 μm to 2 μm, along its positive direction. The polygon forming the base of the pyramid may be hexagonal. The height of the pyramid between the base and the vertex or top plateau varies between 100 nm and 20 μm, preferably between 200 nm and 2 μm.

[0084] In the following description, embodiments will be described in the case of optoelectronic devices having light-emitting diodes including micrometer- or nanometer-wires. However, it should be understood that these embodiments may relate to optoelectronic devices having light-emitting diodes including micrometer- or nanometer-scale pyramids.

[0085] The wire primarily comprises at least one semiconductor material, preferably more than 60% by weight, and more preferably more than 80% by weight. The semiconductor material may be silicon, germanium, silicon carbide, III-V compound, II-VI compound, or a combination of at least two of these compounds.

[0086] Examples of Group III elements include gallium (Ga), indium (In), or aluminum (Al). Examples of Group III-N compounds are GaN, AlN, InN, InGaN, AlGaN, or AlInGaN. Other Group V elements, such as phosphorus or arsenic, may also be used. Typically, the elements in Group III-V compounds can be combined in different mole fractions. Examples of Group II elements include Group IIA elements, particularly beryllium (Be) and magnesium (Mg), and include Group IIB elements, particularly zinc (Zn), cadmium (Cd), and mercury (Hg). Examples of Group VI elements include Group VIA elements, particularly oxygen (O) and tellurium (Te). Examples of Group II-VI compounds are ZnO, ZnMgO, CdZnO, CdZnMgO, CdHgTe, CdTe, or HgTe. Typically, the elements in Group II-VI compounds can be combined in different mole fractions. The semiconductor material of the wire may include dopants, such as silicon ensuring N-type doping of Group III-N compounds, or magnesium ensuring P-type doping of Group III-N compounds.

[0087] Figure 1 This is a partially simplified cross-sectional view of an embodiment of an optoelectronic device 5, which includes micrometer or nanometer wires.

[0088] optoelectronic devices 5 in Figure 1 From bottom to top, the middle section includes:

[0089] - Substrate 10, which includes opposing surfaces 12 and 14, wherein the upper surface 12 is preferably flat at least on the horizontal plane of the light-emitting diode;

[0090] -Seed layer 16, which is made of a material that facilitates line growth and is arranged on surface 12;

[0091] - Insulating layer 18, which covers seed layer 16 and includes openings 20 that expose multiple portions of seed layer 16;

[0092] - Light-emitting diodes (LEDs) (six LEDs are shown), each LED is in contact with the seed layer 16 through one of the openings 20;

[0093] - Insulating layer 24, which extends on the lower side of the light-emitting diode (LED) and on the insulating layer 18 between the LEDs;

[0094] - Layer 26, which forms electrodes covering each light-emitting diode (LED) and further extending on the insulating layer 24 between the LEDs;

[0095] - A reflective conductive layer 28 extends on the layer 26 between the light-emitting diodes (LEDs), wherein the conductive layer 28 may be inserted as a variant between the electrode layer 26 and the insulating layer 24 between the light-emitting diodes (LEDs).

[0096] - Dielectric protective layer 30, which extends on layers 26 and 28;

[0097] - Photoluminescent blocks 32 and 33, which cover specific components of the light-emitting diode;

[0098] Block 34, which is transparent to the radiation emitted by the light-emitting diode and covers other components of the light-emitting diode, may omit the transparent block 34;

[0099] - Insulating layer 36, which covers the upper surface of each block 32, 33, 34 or only a portion of blocks 32, 33, 34, may be omitted;

[0100] - Protective layer 37, which covers the insulating layer 36, the sides of blocks 32, 33, 34 and the electrode layer 26 between blocks 32, 34;

[0101] - Wall 38, which is located between blocks 32 and 34, each wall 38 includes a core 40 surrounded by a reflective coating 42;

[0102] - One, two, or three color filters 44, for example, a single yellow color filter; two color filters, the first being a yellow color filter and the second a red color filter; or three color filters, the first being a red color filter, the second a green color filter, and the third a blue color filter, covering at least a portion of the photoluminescent blocks 32, 33, with a single color filter 44 covering two blocks as an example; and

[0103] - Transparent protective layer 46, which covers the entire structure.

[0104] Figure 2 An embodiment of a light-emitting diode (LED) is shown. According to one embodiment, each LED includes a line 21 in contact with a seed layer 16 through one of openings 20, and a shell 22 comprising a stack of semiconductor layers covering the sidewalls and top of the line 21. The assembly formed by each line 21 and the associated shell 22 constitutes the LED.

[0105] Shell 22 may include a stack of multiple layers, particularly an active layer 23 and an adhesive layer 25. Active layer 23 is the layer from which most of the radiation provided by a light-emitting diode (LED) is emitted. According to one example, active layer 23 may include confinement devices, such as multiple quantum wells. Adhesive layer 25 may include a stack of semiconductor layers having the same III-V material as line 21 but having a different conductivity type.

[0106] Substrate 10 may correspond to a monolithic structure or a layer covering a support made of another material. Substrate 10 is preferably a semiconductor substrate, such as a substrate made of silicon, germanium, silicon carbide, or a III-V compound, such as GaN or GaAs, or a ZnO substrate. Preferably, substrate 10 is a single-crystal silicon substrate. Preferably, it is a semiconductor substrate compatible with manufacturing methods implemented in microelectronics. Substrate 10 may correspond to a multilayer structure of silicon-on-insulator (SOI).

[0107] The cross-section of opening 20 may correspond to the desired cross-section of line 21 or may differ from the cross-section of the line to be obtained. The average diameter of line 21 may be equal to or greater than the average diameter of opening 20.

[0108] Seed layer 16 is made of a material favorable for line growth. As an example, the material forming seed layer 16 can be a nitride, carbide, or boride, or a combination of these compounds, of a transition metal from columns IV, V, or VI of the periodic table. For example, seed layer 16 can be made of aluminum nitride (AlN), boron (B), boron nitride (BN), titanium (Ti) or titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), hafnium (Hf), hafnium nitride (HfN), niobium (Nb), niobium nitride (NbN), zirconium (Zr), zirconium borate (ZrB2), zirconium nitride (ZrN), silicon carbide (SiC), tantalum carbide (TaCN), Mg x N y Magnesium nitride in the form of Mg3N2, where x is approximately equal to 3 and y is approximately equal to 2, for example, magnesium nitride in the form of Mg3N2 or magnesium gallium nitride (MgGaN), tungsten (W), tungsten nitride (WN), or combinations thereof. Seed layer 16 may have a monolayer structure or may correspond to a stack of at least two layers, each layer being made of, for example, one of the aforementioned materials.

[0109] According to one embodiment, the seed layer 16 may be omitted. According to another embodiment, the seed layer 16 may be replaced by, for example, a seed pad formed at the bottom of the opening 20.

[0110] Each insulating layer 18, 24, 30, 36, 37, 46 and the filler material 40 can be made of a dielectric material, such as silicon oxide (SiO2) or silicon nitride (SiO2). x N y Where x is approximately equal to 3 and y is approximately equal to 4, for example, Si3N4), silicon oxynitride (especially the general formula SiO2), where x is approximately equal to 3 and y is approximately equal to 4. x N yMaterials such as Si₂ON₂, aluminum oxide (Al₂O₃), hafnium oxide (HfO₂), titanium dioxide (TiO₂), or diamond. Insulating layers 18, 24, 30, 36, 37, and 46 may have a single-layer structure or correspond to a stack of two or more layers. When insulating layer 18 corresponds to a stack of at least two layers, the upper layer of the stack is insulating, for example, made of a dielectric material.

[0111] The conductive layer 28 or coating 42 preferably corresponds to a metal layer, such as aluminum, silver, copper, gold, or zinc. The thickness of the conductive layer 28 or coating 42 can range from 0.01 μm to 1,000 μm. As a variant, coating 42 can be omitted. In this case, the filler material 40 can be a metallic material, such as aluminum, silver, copper, or zinc.

[0112] Electrode layer 26 allows electromagnetic radiation emitted by the light-emitting diode. The material forming electrode layer 26 can be a transparent and conductive material, such as indium tin oxide (ITO), zinc aluminum oxide, or zinc gallium oxide, or graphene. The thickness of electrode layer 26 can range from 0.01 μm to 10 μm.

[0113] According to one embodiment, each photoluminescent block 32, 33 is located opposite one of the light-emitting diodes (LEDs) or an LED assembly. Each photoluminescent block 32, 33 includes a light-emitting element that, when excited by light emitted by an associated LED, is capable of emitting light at a wavelength different from the wavelength of the light emitted by the associated LED. According to one embodiment, the optoelectronic device 5 includes at least two types of photoluminescent blocks 32, 33. Each first-type photoluminescent block 32 is capable of converting radiation provided by the LED into first radiation of a first wavelength, and each second-type photoluminescent block 33 is capable of converting radiation provided by the LED into second radiation of a second wavelength. According to one embodiment, the optoelectronic device 5 includes at least three types of photoluminescent blocks 32, 33, each third-type photoluminescent block being capable of converting radiation provided by the LED into third radiation of a third wavelength. The first, second, and third wavelengths may be different.

[0114] According to one embodiment, the light-emitting diode is capable of emitting blue light, i.e., radiation with a wavelength in the range of 430 nm to 480 nm. According to one embodiment, a first wavelength corresponds to green light and is in the range of 510 nm to 570 nm. According to one embodiment, a second wavelength corresponds to red light and is in the range of 600 nm to 720 nm.

[0115] According to another embodiment, a light-emitting diode (LED) is capable of emitting ultraviolet radiation, for example. According to one embodiment, a first wavelength corresponds to blue light and is in the range of 430 nm to 480 nm. According to one embodiment, a second wavelength corresponds to green light and is in the range of 510 nm to 570 nm. According to one embodiment, a third wavelength corresponds to red light and is in the range of 600 nm to 720 nm.

[0116] The aspect ratio of blocks 32 and 33, i.e. the ratio of the block's height to its maximum width, can be in the range of 0.01 to 10, preferably in the range of 0.05 to 2.

[0117] According to one embodiment, each photoluminescent block 32, 33 includes particles of at least one photoluminescent material, for example, in a transparent matrix. An example of the photoluminescent material is yttrium aluminum garnet (YAG) activated by trivalent cerium ions, also known as YAG:Ce or YAG:Ce. 3+ The average particle size of conventional photoluminescent materials is generally greater than 5 μm.

[0118] According to one embodiment, each photoluminescent block 32, 33 includes a matrix having nanoscale single-crystal particles of semiconductor material dispersed therein, hereinafter also referred to as semiconductor nanocrystals or nanoluminescent particles. The internal quantum efficiency QY of the photoluminescent material... int It is equal to the ratio of the number of emitted photons to the number of photons absorbed by the photoluminescent material. The internal quantum efficiency QY of semiconductor nanocrystals. int Greater than 5%, preferably greater than 10%, and more preferably greater than 20%.

[0119] According to one embodiment, the average size of the nanocrystals is in the range of 0.5 nm to 1,000 nm, preferably in the range of 0.5 nm to 500 nm, more preferably in the range of 1 nm to 100 nm, and particularly in the range of 2 nm to 30 nm. For sizes smaller than 50 nm, the light conversion properties of the semiconductor nanocrystals depend primarily on quantum confinement. Therefore, semiconductor nanocrystals correspond to quantum dots.

[0120] According to one embodiment, the semiconductor material of the semiconductor crystal is selected from cadmium selenide (CdSe), indium phosphide (InP), cadmium sulfide (CdS), zinc sulfide (ZnS), zinc selenide (ZnSe), cadmium telluride (CdTe), zinc telluride (ZnTe), cadmium oxide (CdO), zinc cadmium oxide (ZnCdO), zinc cadmium sulfide (CdZnS), zinc cadmium selenide (CdZnSe), indium silver sulfide (AgInS2), and perovskites of the PbScX3 type, wherein X is a halogen atom, particularly iodine (I), bromine (Br), or chlorine (Cl), and mixtures of at least two of these compounds. According to one embodiment, the semiconductor material of the semiconductor nanocrystal is selected from the materials mentioned in the publication by Le Blevenec et al., April 2014, in Physica Status Solidi (RRL) - Rapid Research Letters, Vol. 8, No. 4, pp. 349-352.

[0121] According to one embodiment, the size of the semiconductor nanocrystal is selected based on the desired wavelength of the radiation emitted by the semiconductor nanocrystal. As an example, a CdSe nanocrystal with an average size of approximately 3.6 nm is capable of converting blue light into red light, and a CdSe nanocrystal with an average size of approximately 1.3 nm is capable of converting blue light into green light. According to another embodiment, the composition of the semiconductor nanocrystal is selected based on the desired wavelength of the radiation emitted by the semiconductor nanocrystal.

[0122] The matrix is ​​at least partially transparent, preferably greater than 80%, to radiation emitted by photoluminescent particles and / or light-emitting diodes (LEDs). The matrix is ​​made, for example, of silica. Alternatively, the matrix may be made of any at least partially transparent polymer, particularly silicone, acrylic resin, or poly(methyl methacrylate) (PMMA) type or polylactic acid (PLA). The matrix can be made, in particular, of a polymer that is at least partially transparent, and used with three polymers in a 3D printer. The matrix may correspond to photosensitive or non-photosensitive glass (SOG, spin-coated glass) deposited by centrifugal separation. According to one embodiment, the matrix contains 2% to 90%, preferably 10% to 60% by weight to 60% by weight, of nanocrystals, for example, about 30% by weight.

[0123] The thickness of the photoluminescent blocks 32 and 33 depends on the concentration of nanocrystals and the type of nanocrystals used. The height of the photoluminescent blocks 32 and 33 is preferably greater than the height of line 21 and less than or equal to the height of wall 38. In a top view, each photoluminescent block 32 and 33 may correspond to a square, rectangle, "L"-shaped polygon, etc., and its area may be equal to the area of ​​a square with a side length ranging from 1 μm to 100 μm, preferably from 3 μm to 15 μm.

[0124] The wall 38 is at least partially made of at least one reflective material. The reflective material can be a metallic material, particularly iron, copper, aluminum, tungsten, silver-titanium, hafnium, zirconium, or a combination of at least two of these compounds. Preferably, the wall 38 is made of a material compatible with manufacturing methods implemented in microelectronics. Preferably, the wall 38 is made of aluminum or silver.

[0125] The height of the wall 38, measured along a direction perpendicular to surface 12, is in the range of 300 nm to 200 μm, preferably in the range of 3 μm to 15 μm. The thickness of the wall 38, measured along a direction parallel to surface 12, is in the range of 100 nm to 50 μm, preferably in the range of 0.5 μm to 10 μm.

[0126] According to one embodiment, wall 38 may be made of a reflective material or covered with a coating that is reflective of the wavelength of radiation emitted by photoluminescent blocks 32, 33 and / or light-emitting diodes.

[0127] Preferably, the wall 38 surrounds the photoluminescent blocks 32 and 33. Then, the wall 38 reduces crosstalk between adjacent photoluminescent blocks 32 and 33.

[0128] The encapsulation layer 46 is at least partially transparent to radiation emitted by photoluminescent particles and / or light-emitting diodes (LEDs). The encapsulation layer may be made of an inorganic material that is at least partially transparent to radiation emitted by photoluminescent particles and / or light-emitting diodes (LEDs). As an example, the inorganic material is selected from SiO₂. x Types of silicon dioxide, where x is a real number between 1 and 2; or SiO y N z , where y and z are real numbers between 0 and 1; titanium oxide, aluminum oxide, such as Al2O3, and mixtures of these compounds. The encapsulation layer may be made of an organic material that is at least partially transparent. As an example, the encapsulation layer is a silicone polymer, an epoxide polymer, an acrylic polymer, or polycarbonate. Encapsulation layer 46 may have a single-layer or multi-layer structure and may, for example, include a stack of organic and / or inorganic layers.

[0129] Figures 3 to 14 It shows the manufacturing process. Figure 1 The structure obtained in the successive steps of the method embodiment of the optoelectronic device 5 shown.

[0130] Figure 3The structure obtained after performing the following steps is shown: a seed layer 16 is formed on the surface 12 of the substrate 10; an insulating layer 18 is formed on the seed layer 16; openings 20 are etched in the insulating layer 18 to form light-emitting diodes (LEDs); lines are grown in the openings 20, for example by metal-organic chemical vapor deposition (MOCVD) or any other suitable method; a shell covering the lines is formed; an insulating layer 24 is formed under each LED; an electrode layer 26 is formed; a conductive layer 28 is formed; a dielectric layer 30 is formed; and a layer 50 of a material transparent to visible light (particularly a dielectric material) is deposited, filling the spaces between the lines 21 to form a substantially flat upper surface 52 above the dielectric layer 30. Layer 50 can be made of a mineral material (SiO2, SiN, Al2O3) transparent in the visible light range. Layer 50 can be made of resin, particularly a photoresist. Layer 50 can be deposited by spin coating, stencil coating, blade coating, flexographic printing, or screen printing.

[0131] Figure 4 The structure obtained after performing the following steps is shown: namely, depositing a layer 54 as an etching mask on the transparent layer 50, and etching openings 56 in the layer 54 at each desired location of the first type of photoluminescent block 32, and etching openings 58 continuing the openings 56 across the entire thickness of the transparent layer 50. The layer 54 may be made of one of the materials described above for the insulating layers 18, 24, 30, 36, 37, 46. The etching of the insulating layer 54 may be dry etching, such as ion plasma type etching; or wet etching, preferably selective on the material of the transparent layer 50. If the layer 50 is made of SiO2, the layer 54 may be a photoresist and may be removed after the openings 58 are formed. The etching of the transparent layer 50 may be dry etching, such as ion plasma type etching, preferably selective on the protective layer 30.

[0132] Figure 5 The structure obtained after completely filling openings 56 and 58 with the material forming the first type of photoluminescent block 32 is shown. Spin coating or die coating can be used. The filling step results in the formation of a layer 60 of the material forming the photoluminescent block 32 on the insulating layer 54.

[0133] Figure 6The structure obtained after an etching step, particularly a chemical mechanical polishing (CMP) step, to remove layer 60 and insulating layer 54, thereby exposing the upper surface 52 of transparent layer 50, is shown. The CMP step may include mechanical polishing and chemical etching steps simultaneously or sequentially. According to one embodiment, layer 60 can be removed by CMP, and then layer 54 serves as an etch stop layer. Layer 54 is then removed, for example, by dry etching, particularly plasma etching, or by wet etching. This thus defines the photoluminescent block 32. As a variant, layer 54 may not be removed.

[0134] Figure 7 The structure obtained after performing the following steps is shown: namely, depositing a layer 62 on the transparent layer 50 as an etching mask, and etching an opening 64 in the layer 62 at each desired location of the second type of photoluminescent block 33, and etching an opening 66 in the transparent layer 50 across the entire thickness of the transparent layer 50 to continue the opening 64. The layer 62 may be made of one of the materials previously described for insulating layers 18, 24, 30, 36, 37, 46, 56.

[0135] Figure 8 The structure obtained after completely filling openings 64, 66 with the material forming the second type of photoluminescent block 33 is shown. Spin coating or die coating can be used. The filling step results in the formation of a layer 67 of the material forming the photoluminescent block 33 on the transparent layer 50.

[0136] Figure 9 The structure obtained after a CMP step, in which layer 67 and insulating layer 62 are removed to expose the upper surface 52 of transparent layer 50, thus defining photoluminescent block 33, is shown. Alternatively, layer 67 can be removed by CMP, and layer 62 can then be used as an etch stop layer. Layer 62 can then be removed, for example by dry etching, particularly plasma etching, or by wet etching. Alternatively, layer 62 may not be removed.

[0137] Figure 10 The diagram shows the structure obtained after depositing a layer 68 as an etching mask on the transparent layer 50 and photoluminescent blocks 32, 33, and etching an opening 70 in the layer 68 at each desired location on the wall 38.

[0138] Figure 11 The diagram shows the structure obtained after etching the opening 72 that continues the opening 70 across the entire thickness of the transparent layer 50 for each opening 70. Layer 68 may then be retained or not. The remaining portion of the transparent layer 50 forms the transparent block 34. If layer 50 is made of SiO2, layer 68 may be a resist layer and can be removed after the opening 72 is formed.

[0139] Figure 12 It shows in Figure 11 The structure shown is obtained after depositing an insulating layer 37 over the entire structure. The insulating layer 37 can be deposited using conformal deposition methods, particularly atomic layer deposition (ALD). Specifically, the insulating layer 37 can be a layer that protects against moisture and / or air, and can also act as a protective layer for the photoluminescent blocks 32, 33. Advantageously, layer 37 is deposited immediately after the formation of the photoluminescent blocks 32, 33.

[0140] Figure 13 It shows in Figure 12 The structure shown is obtained by depositing a layer 76 made of the material of the coating 42 forming the wall 38 on top of the entire structure, and by filling the opening 72 with the material of the core 40 forming the wall 38 (resulting in the formation of a layer 78 of filling material on blocks 32, 33, 34).

[0141] Figure 14 The diagram illustrates the structure obtained after removing multiple portions of layer 78 (filler material) and multiple portions of layer 76 (external to opening 72) to expose multiple portions of insulating layer 37 covering insulating layer 68, thus defining wall 38, particularly core 40 and coating 42. As an example, the portions of layer 78 (external to opening 72) can be removed by dry etching, while the portions of layer 76 (external to opening 72) can be removed by wet or dry etching.

[0142] The method includes the additional steps of forming a color filter 44 and a protective layer 46.

[0143] Figures 15 to 27 The structure obtained in successive steps of another embodiment of the method for manufacturing optoelectronic device 5 is shown.

[0144] Figure 15 It shows the previous information about Figure 3 , 4 The structure obtained after the same steps described in steps 5 and 6 is different in that the insulating layer 54 is not removed in the CMP step.

[0145] Figure 16 The structure obtained after performing the following steps is shown: namely, depositing a layer 62 as an etching mask over the entire structure, and etching an opening 64 in the layer 62 at each desired location of the second type of photoluminescent block 33, and etching an opening 79 of the continuation opening 64 in the layer 54, and etching an opening 66 of the continuation opening 64 across the entire thickness of the transparent layer 50.

[0146] Figure 17 It shows the previous information about Figure 8The structure is obtained after following steps similar to those described, namely, after completely filling the openings 64, 79, and 66 with the material forming the second type of photoluminescent block 33. Spin coating can be used. The filling step results in the formation of a layer 67 of the material forming the photoluminescent block 33 on the insulating layer 62.

[0147] Figure 18 The structure obtained after a CMP step of removing layer 67 to reach the unremoved insulating layer 62, thus defining the photoluminescent block 33, is shown.

[0148] Figure 19 and 20 It shows the previous information about Figure 10 and 11 The steps described are similar to those described, and the structure obtained after performing the following steps is shown: namely, depositing a layer 68 as an etching mask over the entire structure, and etching an opening 70 in layer 68 at each desired location of wall 38, possibly etching an opening 80 of the continuation opening 70 in layer 62, etching an opening 81 of the continuation opening 70 in layer 54, and etching an opening 72 of the continuation opening 70 across the entire thickness of transparent layer 50.

[0149] Figure 21 The structure obtained after the CMP step of removing insulating layers 54, 62, and 68 is shown. This step can be omitted.

[0150] Figure 22 This shows the execution of the previous discussion. Figure 13 The steps described are similar to the steps (including those described in the original text). Figure 21 The structure shown is obtained by depositing an insulating layer 76 made of the material of the coating 42 forming the wall 38 on top of the entire structure, and by filling the opening 72 with the material of the core 40 forming the wall 38 (resulting in the formation of a layer 78 of filling material on blocks 32, 33, 34).

[0151] Figure 23 The structure obtained after a CMP or dry etching step that removes the filler material from layer 78 and multiple portions of layer 76 located outside the opening 72 to expose multiple portions of insulating layer 37 covering insulating layer 36, thereby defining wall 38, is shown.

[0152] Figure 24 The diagram shows a layer 82 deposited over the entire structure as an etching mask, and the structure obtained after etching openings 83 in layer 82 at each desired location of the third type of photoluminescent block.

[0153] Figure 25 The diagram shows the etched opening 84, the subsequent etched opening 82 across the entire thickness of the transparent layer 50, and the structure obtained after removing layer 80.

[0154] Figure 26 The structure obtained after completely filling opening 84 with the material forming a third type of photoluminescent block is shown. Spin coating can be used. The filling step results in the formation of a layer 88 of the material forming the photoluminescent block on the remaining structure outside opening 84.

[0155] Figure 27 The structure obtained after the CMP step of removing layer 88 is shown. This defines a third type of photoluminescent block 90. ​​Without the transparent block 34 covering the LED as previously described, layer 50 does not need to be made of a highly transparent material because layer 50 no longer has any portion covering the LED at the end of the manufacturing process.

[0156] The method includes the additional steps of forming a color filter 44 and a protective layer 46.

[0157] Figures 28 to 31 The structure obtained in successive steps of another embodiment of the method for manufacturing optoelectronic device 5 is shown.

[0158] The initial steps of this method include previous information regarding... Figures 3 to 18 All steps described.

[0159] Figure 28 The structure obtained after performing the following steps is shown: namely, depositing a layer 82 as an etching mask over the entire structure, and etching an opening 83 in layer 82 at each desired location of the third type of photoluminescent block 90, etching an opening 92 of the continuation opening 83 in layer 62, etching an opening 94 of the continuation opening 83 in layer 54, and etching an opening 84 of the continuation opening 83 across the entire thickness of layer 50.

[0160] Figure 29 The structure obtained after completely filling the opening 84 with the material forming the third type of photoluminescent block 90 is shown. Spin coating can be used. The filling step results in the formation of a layer 88 of the material forming the photoluminescent block 90 on the remaining portion of the structure outside the opening 84.

[0161] Figure 30 The structure obtained after the CMP step of removing layer 88 is shown. This defines the third type of photoluminescent block 90.

[0162] In the foregoing embodiments, the step of forming openings 58, 66, and 84 in layer 50 includes using an etching mask. According to another embodiment, when layer 50 is made of a photoresist, the step of etching openings in layer 50 can be performed directly via a photolithography step.

[0163] Figure 31The structure obtained after performing selective etching to remove mask layers 54, 62, 82 and removing multiple portions of the transparent layer 50 retained between photoluminescent blocks 32, 33, 90 is shown.

[0164] Then, the method can include previous information about Figure 13 and 14 The described steps, in particular, are for forming a wall 38 in the opening released between the photoluminescent blocks 32, 33, and 90.

[0165] Figures 32 to 39 The structure obtained in successive steps of another embodiment of the method for manufacturing optoelectronic device 5 is shown.

[0166] The initial steps of this method include previous information regarding... Figure 3 All steps described.

[0167] Figure 32 The diagram shows the structure obtained after depositing a layer 68 above the transparent layer 50 as an etching mask, and etching an opening 70 in the layer 68 at each desired location of the wall 38.

[0168] Figure 33 The structure obtained after etching the opening 72 across the entire thickness of the transparent layer 50 after each opening 70 is shown.

[0169] Figure 34 This shows the execution of the previous discussion. Figure 13 The steps described are similar to the steps (including those described in the original text). Figure 33 The structure shown is obtained by depositing an insulating layer 76 made of the material of the coating 42 forming the wall 38 on top of the entire structure, and by filling the opening 72 with the material of the core 40 forming the wall 38 (resulting in the formation of a layer 78 of filling material on the transparent layer 50).

[0170] Figure 35 The structure obtained after an etching step that removes layer 78 of filler material and multiple portions of layer 76 outside opening 72, thereby defining wall 38, is shown. As previously described, multiple portions of layer 78 outside opening 72 can be removed by dry etching or CMP, and multiple portions of layer 76 outside opening 72 can be removed by wet or dry etching.

[0171] Figures 36 to 39 It shows the previous separate statements about Figures 24 to 27 The steps described lead to the structure obtained in the formation of the first type of photoluminescent block 32. These steps are repeated once to form the second type of photoluminescent block 33, and may be repeated once to form the third type of photoluminescent block 90.

[0172] Figures 40 to 52The structure obtained in successive steps of another embodiment of the method for manufacturing optoelectronic device 5 is shown.

[0173] The initial steps of this method include previous information regarding... Figure 3 All steps described.

[0174] Figure 40 The structure obtained after depositing layer 100, which serves as an etching mask and covers transparent layer 50, and a resist layer 102 covering layer 100 is shown. Layer 100 may be made of one of the materials previously described for insulating layers 18, 24, 30, 36, 37, 46.

[0175] Figure 41 The structure is shown after etching opening 104 in layer 102 and, at each desired location of the first type of photoluminescent block 32, etching opening 106 in layer 100 to continue opening 104.

[0176] Figure 42 The structure obtained after removing the resist layer 102 and depositing an insulating layer 106 over the entire structure is shown. Layer 106 may be made of one of the materials previously described for insulating layers 18, 24, 30, 36, 37, 46.

[0177] Figure 43 The diagram shows the structure obtained after etching the insulating layer 106, resulting in the formation of multiple portions 108 of the insulating layer 106, called spacers, on the sides of each opening 104, and on the other hand, removing the insulating layer 106. The etching can be dry etching.

[0178] Figure 44 The structure obtained after etching an opening 110 across the entire thickness of the transparent layer 50 is shown. The opening 110 is defined by a mask formed by layer 100 and spacers 108.

[0179] Figure 45 The structure obtained after completely filling the opening 110 with the material forming the first type of photoluminescent block 32 is shown. Spin coating can be used. The filling step results in the formation of a layer 88 of the material forming the photoluminescent block 32 on the remaining portion of the structure outside the opening 110.

[0180] Figure 46 The structure obtained after the CMP step of removing layer 88 is shown. This defines the first type of photoluminescent block 32.

[0181] Figure 47 It shows that in repeating the previous information Figures 40 to 45 The structure obtained after the steps described for defining the second type of photoluminescent block 33.

[0182] Figure 48 The structure is shown after the spacer 108 is removed, for example, by selective etching of the materials forming the photoluminescent blocks 32, 33, the material forming the transparent layer 50, and the material forming the insulating layer 100. Dry etching or wet etching can be used.

[0183] Figure 49 The structure obtained after etching across the entire thickness of the transparent layer 50 in the transparent layer 50 to match the opening 112 formed by removing the spacer 108 is shown.

[0184] Figure 50 It shows in Figure 5 The structure shown is obtained after depositing an insulating layer 37 on top of the entire structure.

[0185] Figure 51 The structure obtained after filling the opening 102 with the material of the core 40 forming the wall 38 (resulting in the formation of a layer 78 of filling material on blocks 32, 33, 34) is shown.

[0186] Figure 52 The structure obtained after a CMP step, in which multiple portions of the filler material layer 78 and the layer 76 located outside the opening 112 are removed to expose multiple portions of the insulating layer 37 on the upper surface of the covering blocks 32, 33, 34, thereby defining the wall 38, is shown.

[0187] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations can be combined, and other variations will occur to them. In particular, the method of manufacturing optoelectronic devices may include additional steps not yet described, such as transferring the structure onto an intermediate support (also called a handle) to allow for manipulation thereon. Finally, actual implementations of the embodiments and variations described herein are based on the functional indications provided above and are within the capabilities of those skilled in the art.

Claims

1. A method of manufacturing an optoelectronic device (5), the optoelectronic device comprising an assembly of a light-emitting diode (LED) having a first component and a second component, and a first photoluminescent block (32) made of a first photoluminescent material, each of the first photoluminescent blocks covering one of the first components, the method comprising forming a layer (50) covering the first component and the second component, defining a first opening (58) in the layer to expose the first component, filling the first opening with the first photoluminescent material and covering the layer (50), and performing a first chemical mechanical polishing to define the first photoluminescent block, wherein the device comprises a second photoluminescent block (33) made of a second photoluminescent material different from the first photoluminescent material, each of the second photoluminescent blocks covering one of the second components, the method comprising, after performing the first chemical mechanical polishing to define the first photoluminescent block, defining a second opening (66) in the layer (50) to expose the second component, filling the second opening with the second photoluminescent material and covering the layer (50) and the first photoluminescent block (32), and performing a second chemical mechanical polishing to define the second photoluminescent block.

2. The method of claim 1, wherein the device further comprises a third component of a light-emitting diode (LED) and a third photoluminescent block (90) made of a third photoluminescent material different from the first and second photoluminescent materials, each of the third photoluminescent blocks covering one of the third components, the method comprising defining a third opening (84) in the layer (50) to expose the third component, filling the third opening with the third photoluminescent material, and performing a third chemical mechanical polishing to define the third photoluminescent block.

3. The method of claim 1, wherein the device further comprises a fourth component of a light-emitting diode (LED), the method comprising defining a fourth photoluminescent block (34) in the layer (50), each of the fourth photoluminescent blocks covering one of the fourth components of the light-emitting diode.

4. The method of claim 3, wherein the layer (50) is at least partially transparent to radiation emitted by the light-emitting diode of the fourth component of the light-emitting diode (LED).

5. The method of claim 1, further comprising defining a fourth opening (72) in the layer (50) between the components and forming a wall (38) having a reflective side in the fourth opening.

6. The method of claim 5, comprising depositing a reflective coating (42) in the fourth opening (72) and filling the remainder of the fourth opening with a fifth material.

7. The method of claim 5, wherein the wall (38) is formed after the first photoluminescent block (32).

8. The method of claim 7, comprising forming a barrier layer (37) extending in the fourth opening (72) and covering the first photoluminescent block (32) prior to forming the wall (38).

9. The method of claim 5, wherein the wall (38) is formed after the first and second photoluminescent blocks (32, 33).

10. The method of claim 5, wherein the wall (38) is formed in front of the first and second photoluminescent blocks (32, 33).

11. The method of claim 5, wherein the device further comprises a third component of a light-emitting diode (LED) and a third photoluminescent block (90) made of a third photoluminescent material different from the first and second photoluminescent materials, each of the third photoluminescent blocks covering one of the third components, the method comprising defining a third opening (84) in the layer (50) to expose the third component, filling the third opening with the third photoluminescent material, and performing a third chemical mechanical polishing to define the third photoluminescent block, the method comprising etching the layer (50) present between the first, second, and third photoluminescent blocks (32, 33, 90), forming a barrier layer (37) extending in the fourth opening (72) and covering the first, second, and third photoluminescent blocks (32, 33, 90) prior to forming the wall (38), and forming the wall (38) in the space present between the first, second, and third photoluminescent blocks (32, 33, 90).

12. The method of claim 1, comprising depositing an etch mask layer on the layer, and etching a fifth opening in the etch mask layer at each desired location of each first photoluminescent block, and etching a first opening in the layer to continue the fifth opening.

13. A method of manufacturing an optoelectronic device, the optoelectronic device comprising an assembly of a light-emitting diode (LED) having a first component and a second component, and a first photoluminescent block made of a first photoluminescent material, each of the first photoluminescent blocks covering one of the first components; the method comprising forming a layer covering the first component and the second component, defining a first opening in the layer to expose the first component, filling the first opening with the first photoluminescent material and covering the layer (50), and performing chemical mechanical polishing to define the first photoluminescent blocks; the method comprising defining a fourth opening in the layer between the components and forming a wall having a reflective side in the fourth opening; wherein the wall is formed after the first photoluminescent blocks.

14. A method of manufacturing an optoelectronic device, the optoelectronic device comprising an assembly of a light-emitting diode (LED) having a first component and a second component, and a first photoluminescent block made of a first photoluminescent material, each of the first photoluminescent blocks covering one of the first components; the method comprising forming a layer covering the first component and the second component, defining a first opening in the layer to expose the first component, filling the first opening with the first photoluminescent material and covering the layer (50), and performing chemical mechanical polishing to define the first photoluminescent blocks, wherein the optoelectronic device comprises a second photoluminescent block made of a second photoluminescent material different from the first photoluminescent material, each of the second photoluminescent blocks covering one of the first components; One of two components, the method comprising, after performing the chemical mechanical polishing to define the first photoluminescent block, defining a second opening in the layer to expose the second component, filling the second opening with the second photoluminescent material and covering the layer (50) and the first photoluminescent block (32), and performing chemical mechanical polishing to define the second photoluminescent block; wherein the optoelectronic device further comprises a fourth component of a light-emitting diode (LED), the method comprising defining a fourth photoluminescent block in the layer, each of the fourth photoluminescent blocks covering one of the fourth components of the light-emitting diode; wherein the layer is at least partially transparent to radiation emitted by the light-emitting diode of the fourth component of the light-emitting diode (LED).

15. The method of claim 14, further comprising defining a fourth opening in the layer between the components and forming a wall having a reflective side in the fourth opening.

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