Light-emitting display device, method for manufacturing such device, and light-emitting display system

Abstract

To provide a method for manufacturing light-emitting display devices from islands separated by trenches. [Solution] The method is, - Filling the trench with insulating structural elements, - To form protective strips (108) that partially cover each island and overlap the structural elements, - Partially etching the structural element so that a support (109) is formed beneath the protective strip so that the protective strip has cantilever-shaped portions (110a, 110b), - Depositing an organic layer that is divided into two distinct and separate parts: a first part that extends continuously over each island and over the protective strip, and a second part that extends over the substrate. Includes.

Description

Technical Field

[0001] The technical field of the present invention relates to optoelectronic devices, and more particularly, to matrix display devices having an organic light-emitting layer.

[0002] The present invention relates to a method for manufacturing an OLED (Organic Light-Emitting Diode) type light-emitting display device, and a method for manufacturing such a device.

[0003] The present invention finds an advantageous use in the manufacture of display screens for electronic devices, particularly for the manufacture of high-resolution color display screens such as AMOLED (Active Matrix Organic Light-Emitting Diode) display screens. The term "high resolution" means pixels having a size of less than 15 μm.

Background Art

[0004] In the field of matrix display devices having an organic light-emitting layer, OLED type matrix microdisplays having pixels arranged at a pitch of less than 20 μm, typically between 4 μm and 12 μm, are known.

[0005] When this type of matrix display is color, each pixel is subdivided into sub-pixels of different colors (typically three colors having red, green, and blue) that work together to emit the desired color for the pixel. The surface of the sub-pixel can be rectangular, square, or other shapes (e.g., octagonal), and its size can be determined by the color. The typical size of the sub-pixel can range from 1 μm to 20 μm.

[0006] Each subpixel is generally formed by several superimposed layers, including a lower electrode (anode) deposited on a common substrate, several organic layers (at least one of which is emitting) forming an OLED stack on each lower electrode, and an upper electrode (cathode).

[0007] The documents French Patent Application Publication No. 3079909A1 and U.S. Patent Application Publication No. 2023 / 0041252(A1) describe structures for forming such small-sized OLED pixels (or OLED subpixels) that are improved and industry reliable.

[0008] These structures share the common advantage of allowing smooth discretization of the OLED stack and cathode to form pixels (or subpixels). The term "smooth discretization" refers to a construction method that maintains the performance of the OLED stack.

[0009] In particular, the solutions offered are based on performing discretization of OLED stacks in a manner other than through masking and removal steps, which typically require environments harmful to organic materials (humidity, temperatures above 90°C, solvents, ultraviolet light, etc.).

[0010] The French Patent Application Publication No. 3079909A1 thus describes a first OLED display device in which the lower electrodes of each subpixel are separated from each other by insulating walls rising perpendicularly from the substrate. Each wall acts as a separator between two adjacent subpixels.

[0011] The same document, French Patent Application Publication No. 3079909, describes a second device in which the insulating wall is replaced with a trench into which an insulating layer is deposited.

[0012] Insulating walls and trenches are formed before the OLED stack is deposited by thermal evaporation and serve the same purpose. Because the evaporation deposition technique is primarily directional, the OLED stack is preferentially deposited on the horizontal walls of the device rather than on the side walls of the insulating walls or trenches. The OLED stack is therefore fragmented (or discretized) at the insulating walls or trenches.

[0013] Nevertheless, in reality, the directionality of deposition in OLED stacks is never perfect. Organic particles can therefore also be deposited on the insulating walls or trench sidewalls. Furthermore, these particles are undesirable because they degrade the insulators (electrical and optical) between subpixels. Adjacent subpixels can therefore influence each other, for example, through capacitive coupling or parasitic currents. These phenomena, known as crosstalk, lead to a degradation in the performance of the display device. These phenomena are exacerbated when the subpixels are so-called "tandem" organic light-emitting diodes, that is, when the subpixels consist of several OLED stacks connected in a continuous stack by an interconnection layer.

[0014] The U.S. Patent Application Publication No. 2023 / 0041252A1 provides a solution to this problem by describing a subpixel separator that is placed on a substrate and has a mushroom-shaped structure (or, in the terminology used in this document, a “hangover”). More precisely, the mushroom-shaped structure comprises a lower portion having sloping sides that form the stem of the mushroom. The mushroom-shaped structure also comprises an upper portion that is wider than the lower portion and masks an area of ​​the substrate. This upper portion forms the cap of the mushroom.

[0015] Subpixels are formed when the mushroom structure is positioned correctly. The OLED stack is then deposited on top of these structures and divided in the upper portion. Since it is impossible for organic material to be deposited in the areas of the substrate masked by the upper portion or on the sidewalls of the mushroom structure, the division of the OLED stack is carried out with sufficient reliability (the lower portion is hidden by the upper portion and therefore inaccessible from above). Thus, the degree of directionality of the OLED stack deposition is irrelevant. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] French Patent Application Publication No. 3079909 Specification [Patent Document 2] U.S. Patent Application Publication No. 2023 / 0041252 [Overview of the project] [Problems that the invention aims to solve]

[0017] Nevertheless, these mushroom-shaped structures are particularly complex to fabricate and not very compact (in the vertical direction, they are about 1 μm high). Furthermore, fabricating a common upper electrode (cathode) requires the use of specific equipment to deposit the material at the desired angle. This actually involves carrying out the deposition of the conductive layer beneath the upper part of the mushroom structure at a very specific angle determined by the inclination of the lower part. Thus, using such a fabrication method is neither easy nor economically advantageous.

[0018] Therefore, there is still a need for methods to manufacture OLED display devices with improved resolution that are not too expensive and are easier to implement. [Means for solving the problem]

[0019] The present invention provides a solution to previously discussed problems by enabling the formation of a common upper electrode (the upper electrode is generally a common cathode) between several pixels using a separation structure integrated into the lower electrode of the pixels (these are often the anodes of those pixels). To this end, the present invention enables the discretization of the lower portions of two adjacent pixels by providing a continuous surface between these two pixels to form a layer of organic material and a continuous upper electrode.

[0020] One aspect of the present invention is a method for manufacturing a light-emitting display device from a precursor, wherein the precursor comprises a plurality of islands arranged on a substrate, each island comprising a support layer extending on the substrate and a conductive layer extending on the support layer, and the islands are separated in pairs by trenches, and the method is - Each trench separating the islands is filled with structural elements that provide electrical insulation between the islands, and the filling is carried out for each trench until the structural elements reach the top of the island separated by the trench. - To form at least one protective strip, each protective strip connecting the two islands to each other by overlapping a trench separating the two islands and covering structural elements extending within the trench, and each protective strip partially covering each of the two islands to which it connects, - Selectively partially etching structural elements with respect to each protective strip and with respect to the conductive layer of the island, the partial etching including at least one isotropic etching phase, the partial etching being carried out so as to retain only a part of the structural elements disposed under each protective strip, said part forming a support for each protective strip, and the partial etching being further carried out so that at least one part of each protective strip extends like a cantilever beyond the support that supports at least one part of that protective strip; - Anisotropically depositing an organic layer at an angle substantially perpendicular to the substrate, the organic layer being in two separate and distinct parts, including a first part extending continuously over each island and each protective strip and a second part extending over the substrate, the thickness of the organic layer being selected such that the second part of the organic layer does not reach the at least one cantilever-like part of each protective strip; relates to a method comprising.

[0021] Each island comprises a conductive layer capable of forming a lower electrode. The use of a support layer for each island makes it possible to dispose this conductive layer above the substrate. The protective strips extend from one island to another and are supported by insulating elements. Each protective strip forms a bridge between two islands. This bridge makes it possible for an organic layer to be formed continuously over the islands without any discontinuity between the islands. An additional conductive layer can thus be deposited on this organic layer so as to form a continuous upper electrode without any discontinuity between the islands. This makes it possible to form a common upper electrode (for example, a common cathode) for all the islands.

[0022] Removing a part of the structural element under each protection strip thus enables the formation of a bridge having a cantilever-type section perpendicular to the substrate in the trench. The "cantilever-type part" means a suspended or unsupported part. Thus, there is a discontinuity between the edge of the bridge and the substrate. Thus, depositing an organic material on the island and the bridge results in two separate parts of the organic material with no electrical contact between them. During deposition, a part of the organic material is deposited on each protection strip, especially on the cantilever-type part of each protection strip, while another part falls on the substrate between the islands. The presence of the cantilever-type part breaks the continuity between the protection strip and the substrate. Depending on the thickness of the deposited organic material, as long as the part extending on the substrate cannot reach the cantilever-type part, the two parts of the organic material (the parts on the bridge and the island, and the part on the substrate) remain separate and have no physical and electrical continuity.

[0023] Thus, it is possible to form a common organic layer and electrode for several islands without the risk of short-circuiting the lower electrode and without the risk of electrical contact with surrounding elements (such as additional islands not intended to be connected to these islands). This makes it possible to produce a display device of better quality and, similarly, to simplify its manufacture. In practice, full wafer deposition can be used to form the active elements and upper electrodes of the final pixels, even if the orientation is incomplete.

[0024] Furthermore, when the device comprises three or more islands separated from each other by trenches, it is possible to connect the islands in pairs with pre-fabricated bridges to form a common organic layer and / or common cathode. There is no need to provide additional isolation elements to ensure electrical insulation between the final pixels. Thus, it is possible to form separate chains of pixels, each chain having a common cathode. This reduces the number of steps that must be performed compared to conventional solutions. The manufacturing method is therefore simpler and faster to implement.

[0025] Conveniently, the partial etching of the structural elements is carried out such that the lateral gap between at least one cantilever portion of each protective strip relative to the struts supporting at least one cantilever portion is exactly greater than 100 nm.

[0026] Conveniently, in each trench, filling is carried out until the structural element extends beyond the conductive layer of the two islands separated by the trench by a height between 10 nm and 100 nm.

[0027] Conveniently, each island has a sacrificial layer extending over the conductive layer before filling each trench, and the filling of each trench by structural elements is carried out so that the structural elements reach the top of the sacrificial layer extending over the island.

[0028] Conveniently, the method further includes selectively etching the sacrificial layer of each island against the structural element after filling each trench and before forming each protective strip, so as to be carried out to stop at the conductive layer of the island.

[0029] Conveniently, filling each trench with structural elements is possible. - Depositing a layer of electrical insulating material to completely fill the trench, - Polish the layers of electrical insulating material so that they stop at the sacrificial layer of each island. Includes.

[0030] Conveniently, filling each trench with structural elements involves the following steps: - Conformally depositing a dielectric layer within the trench, - Depositing a layer of filler material onto the dielectric layer so as to completely fill the trench, - Polish the dielectric layer and packing layer so that they stop at the sacrificial layer of each island. Includes.

[0031] Conveniently, the filler material is either amorphous silicon or polycrystalline silicon.

[0032] Conveniently, the method involves creeping or expanding the structural elements before forming each protective strip so that the structural elements cover a portion of the conductive layer of each island, forming at least one continuous, undulating free surface extending from the conductive layer of one island to the conductive layer of another island, wherein each free surface has a gradient measured with respect to the substrate between -45 degrees and 45 degrees, and preferably between -20 degrees and +20 degrees.

[0033] Conveniently, each protective strip is electrically insulating.

[0034] Conveniently, partial etching of structural elements involves, for example, alternating at least one anisotropic etching phase and at least one isotropic etching phase, with each anisotropic etching phase carried out in a direction substantially perpendicular to the substrate.

[0035] Conveniently, the method involves depositing an organic layer, and then anisotropically depositing an additional conductive layer which comprises two distinct and separate parts of the additional conductive layer, including a first part of the additional conductive layer extending continuously over a first part of the organic material layer and a second part of the additional conductive layer extending over a second part of the organic layer, wherein the deposition thickness of the additional conductive layer is selected such that the second part of the additional conductive layer does not reach the at least one cantilevered portion of each protective strip.

[0036] Conveniently, the partial etching of the structural elements is further carried out for each island, by partially etching the support layer of each island such that at least one portion of the conductive layer of the island extends beyond the support layer of the island in a cantilever-like manner.

[0037] Another aspect of the present invention is a light-emitting display device comprising a plurality of islands arranged on a substrate, wherein each island comprises a support layer extending on the substrate and a conductive layer extending on the support layer, and the device is - At least one trench separating the islands into pairs, - At least one protective strip, each protective strip connecting the two islands by overlapping a trench separating the two islands and covering a support extending into the trench, and each protective strip partially covering each of the two islands, - At least one support column for at least partially filling a trench and electrically insulating the island separated by the trench, wherein each column reaches or extends beyond the top of the two islands separated by the trench, and each column is positioned below the protective strip to support the protective strip such that at least one portion of the protective strip extends beyond the column in a cantilever-like manner, - An organic layer having two distinct and separate parts, including a first portion that extends continuously over each island and over each protective strip, and a second portion that extends over the substrate without reaching the at least one cantilever-shaped portion of each protective strip. This relates to a light-emitting display device equipped with the following features.

[0038] Conveniently, the lateral gap of each protective strip between the support struts that support the at least one cantilevered portion is exactly greater than 100 nm.

[0039] Conveniently, at least one of the support columns is made of an electrically insulating material.

[0040] Conveniently, the at least one support comprises a dielectric layer for electrically insulating the islands separated by the at least one support, and an insulating or non-insulating filler for providing support to the protective strip, wherein the dielectric layer of the at least one support separates the filler of the at least one support from each island.

[0041] Conveniently, at least one of the pillars has a continuous, smooth surface over which the protective strip extends, the continuous, smooth surface extending from the conductive layer of one of the islands to the conductive layer of another island, and each continuous, smooth surface has a gradient measured with respect to the substrate between -45 degrees and 45 degrees, and preferably between -20 degrees and +20 degrees.

[0042] The present invention further, - The device according to the present invention, - An active addressing matrix comprising multiple transistors, wherein each of the multiple transistors is connected to the conduction layer of one of the islands (multiple) of the device, and This relates to a light-emitting display system that includes the following features.

[0043] The present invention and its various applications will be better understood by reading the following description and examining the attached diagrams.

[0044] The figures are used to illustrate the objectives of the present invention and are not intended to limit them. Unless otherwise specified, the same elements appearing in different figures shall have a single reference number. [Brief explanation of the drawing]

[0045] [Figure 1] This figure schematically illustrates one embodiment of a precursor for a display device according to the present invention. [Figure 2] This figure schematically illustrates one embodiment of a precursor for a display device according to the present invention. [Figure 3] This figure schematically illustrates one embodiment of a precursor for a display device according to the present invention. [Figure 4] This figure schematically illustrates the first step in a method for manufacturing a display device according to the present invention. [Figure 5] This figure schematically illustrates the first step in a method for manufacturing a display device according to the present invention. [Figure 6] This figure schematically illustrates the first step in a method for manufacturing a display device according to the present invention. [Figure 7] This figure schematically illustrates the second step in a method for manufacturing a display device according to the present invention. [Figure 8] This figure schematically illustrates the second step in a method for manufacturing a display device according to the present invention. [Figure 9] This figure schematically illustrates the second step in a method for manufacturing a display device according to the present invention. [Figure 10]This figure schematically shows an example of a protective strip according to the present invention. [Figure 11] This figure schematically shows an example of a protective strip according to the present invention. [Figure 12] This figure schematically illustrates two other examples of the protective strip according to the present invention. [Figure 13] This figure schematically illustrates two other examples of the protective strip according to the present invention. [Figure 14] This figure schematically illustrates the third step in the method for manufacturing a display device according to the present invention. [Figure 15] This figure schematically illustrates the third step in the method for manufacturing a display device according to the present invention. [Figure 16] This figure schematically illustrates the third step in the method for manufacturing a display device according to the present invention. [Figure 17] This figure schematically illustrates the third step in the method for manufacturing a display device according to the present invention. [Figure 18] This figure schematically illustrates the fourth step in the method for manufacturing a display device according to the present invention. [Figure 19] This figure schematically illustrates the fourth step in the method for manufacturing a display device according to the present invention. [Figure 20] This figure schematically illustrates the fourth step in the method for manufacturing a display device according to the present invention. [Figure 21] This figure schematically illustrates the fifth step in the method for manufacturing a display device according to the present invention. [Figure 22] This figure schematically illustrates the fifth step in the method for manufacturing a display device according to the present invention. [Figure 23] This figure schematically illustrates the fifth step in the method for manufacturing a display device according to the present invention. [Figure 24]This diagram schematically illustrates four steps of one alternative manufacturing method according to the present invention. [Figure 25] This diagram schematically illustrates four steps of one alternative manufacturing method according to the present invention. [Figure 26] This diagram schematically illustrates four steps of one alternative manufacturing method according to the present invention. [Figure 27] This diagram schematically illustrates four steps of one alternative manufacturing method according to the present invention. [Figure 28] This diagram schematically illustrates four steps of one alternative manufacturing method according to the present invention. [Modes for carrying out the invention]

[0046] This invention aims to improve the manufacturing of organic light-emitting display devices with improved resolution, also known as OLED (Organic Light-Emitting Diode) microdisplays.

[0047] In the following description, the term "pixel" refers to a subpixel, or the smallest element, comprising a pixel in the light-emitting display device 200.

[0048] The pixels have a transverse dimension of preferably less than 20 μm, or possibly less than 10 μm, preferably between 5 μm and 1 μm, for example equal to 3 μm. The pixels are arranged with a pitch of, for example, less than 20 μm, for example between 4 μm and 12 μm. Viewed from above, the pixels have a rectangular shape with, for example, a length:width ratio of about 3:1. From here on, the size of the pixel refers to the square side.

[0049] The present invention thus relates to a method for manufacturing a light-emitting display device from a precursor 100. An example of the precursor 100 is illustrated in Figures 1 to 3. These figures show the precursor 100 in particular a top view (Figure 1), as well as two cross-sections (Figures 2 and 3) corresponding to the directions X and Y shown in Figure 1.

[0050] In this example, the precursor comprises a substrate 102 and a plurality of islands 101. The islands 101 are for forming the final pixels of the display device 200. The islands 101 have a rectangular shape when viewed from above. Alternatively, the islands 101 can have a square, triangular, hexagonal, circular, or any other shape. The islands 101 are arranged on the substrate 101 in two groups, three groups of two islands as specified herein. Each group of two islands forms a column and is aligned, for example, parallel to direction Y. One section of the group of two islands 101 corresponds to the section in Figure 3. The three columns (i.e., three groups of two islands 101) are dispersed along the perpendicular direction X. The islands 101 may be further aligned, for example, along direction X, thereby forming lines of islands 101. The islands 101 can be arranged along direction X or Y with a pitch of less than 20 μm, for example, between 4 μm and 12 μm. Therefore, groups of islands can be arranged with a pitch of less than 20 μm, for example, between 4 μm and 12 μm. Alternatively, the islands can be arranged individually. For example, the islands within a group can be arranged according to a hexagonal grid (also called a honeycomb grid). The pitch is therefore configured to correspond to a hexagonal arrangement with a pitch of less than 20 μm, for example, between 4 μm and 12 μm.

[0051] Conveniently, the substrate 102 is a specialized circuit or ASIC (Application Specific Integrated Circuit) of the CMOS (Complementary Metal Oxide Semiconductor) type. In this case, the substrate 102 is opaque and therefore advantageously configured for manufacturing a top-emission type light-emitting display device. In the following description, the terms “transmissive” and “opaque” refer to elements having light transmittance coefficients greater than 60% and less than or equal to 60% for at least one wavelength in the spectral band [400nm;1000nm] or possibly [400nm;2000nm].

[0052] It should be noted that the substrate 102 may, alternatively, be made from amorphous silicon, polycrystalline silicon, and / or deposited on a glass plate. In the latter case, the substrate 102 is transparent and therefore can be configured to manufacture a “bottom emission” type light-emitting display device.

[0053] The substrate 102 includes an addressing circuit (not shown) configured to address the final pixel of the display device 200. The substrate 102 may also include an electrical insulating layer, which may be an oxide, nitride, or oxynitride. This insulating layer is formed from, for example, silicon nitride (SiN). The substrate 102 may further include a plurality of contact islands arranged across the insulating layer to make electrical contact with the final pixel of the device 200.

[0054] All islands 101 are separated from each other by at least trenches 106. Trenches 106 separate columns and rows of islands 101. In other words, within a group of islands 101, islands 101 are separated by trenches 106. Each trench 106 is dug from the top of island 101 down to the substrate 102. The trenches 106 can partially separate islands 101 by digging partway up to the height of the island (islands 101 may share a bottom portion, for example). The trenches 106 may also be dug into the substrate 102 to improve the insulation of the islands 101. The islands 101 can be arranged at a pitch of less than 20 μm, for example, between 4 μm and 12 μm. The width of the trench 106 separating two adjacent islands 101 is, for example, between 0.3 μm and 1.5 μm.

[0055] Islands 101 in the same group (for example, in the same column) are intended to form pixels that will emit, for example, the same wavelength range. The three columns of illustrated island 101 correspond to different wavelengths, for example, the wavelengths corresponding to blue, green, and red, respectively.

[0056] Each island 101 has a mesa shape. That is, each island 101 is defined by a single flank 112 extending from the substrate 101 to the top of the island 101. The flank 112 of the island further forms the edge of the trench 106. Viewed from above, the island 101 can have a rectangular shape with a height:width ratio of approximately 3:1 with an error of no more than 10%. The island 101 may be square, hexagonal, circular, or similar in shape. Each of these, when viewed from above (Figure 1), conveniently has a thickness of 40 μm. 2 Less than 30 μm, preferably 30 μm 2 and 1 μm 2 Between, for example, 5 μm 2 It has a surface area equal to .

[0057] Each island 101 comprises a support layer 104 extending over the substrate 102. Each island 101 may extend in direct contact with the substrate 102 or be separated from the substrate 102 by another layer (e.g., a diffusion barrier or a layer that promotes specific crystallographic growth). The support layer 104 has a thickness H104 which can be between 150 nm and 1000 nm. The support layer 104 can be conductive, in which case it can be made from aluminum Al, copper-aluminum alloy AlCu, chromium Cr, or possibly silver Ag. Alternatively, the support layer 104 can be electrically insulating, in which case it can be made from a dielectric such as silicon oxide SiO2, silicon nitride SiN, or aluminum oxide Al2O3.

[0058] Each island 101 also comprises a conductive layer 103. The conductive layer 103 is intended to form the electrodes of the final pixels, and in this specification, the lower electrodes. For the remainder of this description, the conductive layer 103 may be referred to without distinction as the “lower electrode”. The lower electrode 103 extends over the support layer 104. The lower electrode 103 may extend in direct contact with the support layer 104 or be separated from the support layer 104 by another layer (such as a diffusion barrier or a layer that promotes specific crystallographic growth). The lower electrode 103 is preferably parallel to the substrate 102.

[0059] The lower electrode 103 may be reflective, for example, in the case of a “top emission” type light-emitting display device. The support layer 104 is conveniently reflective or opaque. In top emission, all or part of the support layer 104 may also be conductive. The support layer 104 includes, for example, an insulating portion (surrounding the means for contacting vias located beneath the island). The support layer 104 may also be conductive. The term “reflective” means a surface or element having a light reflectance coefficient greater than 60% for at least one wavelength in the spectral band [400 nm; 1000 nm] or possibly [400 nm; 2000 nm]. The lower electrode 103 may also be transparent, for example, in the case of a “bottom emission” type light-emitting display device. In this case, the support layer 104 is conveniently transparent. The support layer 104 includes, for example, an insulating portion made of a transparent dielectric material (surrounding the means for contacting vias located beneath the island). Nevertheless, the support layer 104 is conveniently conductive. The support layer 104 includes means for connecting islands to vias placed on the substrate 102 (see conductive pillars 116 described below). The support layer 104 may also be entirely conductive.

[0060] The lower electrode 103 may, alternatively, comprise several stacked sublayers. Each sublayer is therefore formed from a different metallic material or metallic alloy. The metallic material (or metallic alloy) used to form the first conductive layer 103 preferably all have properties that allow them to withstand etching chemicals of the support layer 104 and / or structural element 107.

[0061] When the support layer 104 is insulating and comprises a dielectric such as SiO2, the lower electrode 103 may be formed from a metallic material or a conductive alloy. The lower electrode 103 comprises a stack of conductive sublayers such as Ti / TiN / SnO2. In this case, the thickness of the lower electrode 103 is preferably greater than 20 nm, and preferably between 40 nm and 100 nm. Alternatively, the lower electrode 103 may be formed from a transparent conductive oxide (i.e., TCO) to create a "bottom emission" light-emitting display device.

[0062] When the support layer 104 is conductive, the lower electrode 103 is preferably formed from a permeable conductive oxide such as indium tin oxide (ITO), zinc oxide (ZnO), aluminum-doped zinc oxide (AZO), or tin oxide (SnO2).

[0063] When the lower electrode 103 is a stack of conductive sublayers, these sublayers may be formed from titanium nitride (TiN), tin oxide (SnO2), poly(3,4-ethylenedioxythiophene) (or PEDOT), or ITO, or zinc oxide (ZnO), or AZO. Preferably, the sublayer that will be in contact with the organic layer is tin oxide (SnO2), while the sublayer that will be in contact with the support layer 104 is titanium nitride (TiN).

[0064] The lower electrode 103 preferably has a thickness between 4 nm and 20 nm. When the lower electrode 103 comprises a stack of sublayers, the thickness may vary depending on the function of the material. For example, a TCO sublayer has a thickness between 10 nm and 20 nm. A TiN sublayer has a thickness of less than 10 nm, preferably between 4 nm and 8 nm.

[0065] The support layer 104 is intended to support the lower electrode 103. In other words, the support layer 104 is a connecting element between the substrate 102 and the lower electrode 103, ensuring that the lower electrode 103 is held on the substrate 102. The lower electrode 103 is therefore not in direct contact with the substrate 102.

[0066] The support layer 104 is at least partially conductive and therefore also serves to provide electrical connections between the lower electrode 103 and the contact pads or vias (and thus the final pixels) located beneath the island. For each island 101, if the support layer 104 is not conductive, the support layer 104 may have conductive pillars 116 (e.g., pillars are shown only in Figures 2 and 3) in contact with the lower electrode 103 and surrounded by a dielectric material (such as those previously mentioned). The presence of the dielectric material in this layer 104 provides or improves the mechanical retention of the lower electrode 103.

[0067] To simplify this explanation, the remainder of this explanation, unless otherwise stated, considers only two adjacent islands 101 in the same column. Two adjacent islands 101 in the same column correspond to the islands in Figures 3, 6, 9, 12, 13, 16, 19, 22, 24, 25, 26, 27, and 28, for example. In other words, two adjacent islands 101 separated by the same trench 106 are considered. The teachings described below can be applied to columns of three or more islands 101, and it is sufficient to consider two islands 101 at a time.

[0068] Figures 4 to 9 show the step of filling a trench 106 that separates the two islands 101 with a structural element 107. This structural element 107 thus separates the two islands 101 while ensuring electrical insulation between them. Preferably, the structural element 107 fills the entire trench 106 and is in direct contact with the two islands 101.

[0069] At the end of filling, the structural element 107 reaches the top of the two islands 101. In other words, the structural element 107 has a height H107 measured perpendicular to the substrate 102 and from this substrate that is greater than or equal to the height H101 of the islands 101, and preferably equal to the height H101 of the islands 101. The height H101 is measured, for example, from the substrate 102 to the top of each island 101.

[0070] In one mode of implementation, filling the trench 106 is carried out until the conductive layer 103 is reached. "Reaching the conductive layer" means that the structural element 107 has a height measured from the substrate 102 that allows it to be in direct contact with the conductive layer 103. In other words, the structural element 107 is either the same height as the conductive layer 103 or extends beyond it. Preferably, the structural element 107 is the same height as the conductive layer 103.

[0071] In one alternative to the method detailed below, the islands 101 may have sacrificial layers 105 that increase the total height H101 of each island 101. If sacrificial layers 105 are present, filling the trenches 106 is carried out until it reaches the top of the islands 101, i.e., the top of the sacrificial layers 105. From this point onward, the structural elements 107 extend beyond the conductive layer 103.

[0072] According to this alternative, the height difference H73 = H107 - H103 between the structural element 107 and the conductive layer 103 is greater than or equal to zero. The conductive layer 103 is non-planar and can have different heights. In this case, the height is considered to be equivalent to the vertical plane of the flank 112 of the island 101, and in particular, the vertical plane of the portion in contact with the structural element 107.

[0073] Figures 10 to 13 illustrate the protective strip 108. The protective strip 108 forms a bridge between two islands 101 in the same row. The protective strip 108 thus allows for the support of a continuously extending and one-piece structure of organic material over the two islands 101.

[0074] The protective strip 108 is therefore a single, continuous layer without any discontinuity or breaks, extending from one island 101 to the other island 101. The protective strip 108 covers only a portion of each island 101. In this way, the layer of organic material can be in direct contact with the rest of each lower electrode 103.

[0075] The protective strip 108 also extends over the structural element 107 separating the two islands, covering at least a portion of the structural element 107. Figure 10 illustrates three examples of the protective strip 108. According to the first preferred example, in the first column (left column), the protective strip 108 extends over a portion of the lower electrode 103 of one island 101 and extends along direction Y to the other island 101 in the column. The mask 108 covers only small portions of each island 101 and small portions of the structural element 107. According to the second example, in the second (center) column, the protective strip 108 partially passes over the surface of each lower electrode 103 and extends over the larger portion of each lower electrode 103. According to the third example, in the third column (right), the protective strip 108 extends as an extension of the two islands 101, completely covering the structural element 107 separating the two islands 101. Figure 11 shows cross-sections of these different examples.

[0076] The protective strip 108 forms a bridge that allows a continuous layer of material to be deposited on two adjacent islands 101. The protective strip 108 may be necessary to form a continuous layer on three or more islands 101, for example, to connect all islands belonging to the same row of islands 101. In this case, several protective strips 108 may be formed, each covering two adjacent islands 101 and a structural element 107 separating the two adjacent islands 101.

[0077] It may be advantageous for each protective strip 108 to be limited to just two adjacent islands 101 (and associated structural elements 107). However, in order to form a continuous layer over three or more islands 101, the protective strips may be formed to cover each of these islands 101 while maintaining a continuous single, integrated structural layer. Otherwise, it may be preferable for each protective strip 108 to be limited to just two islands 101 (and associated structural elements 107), and strictly to these two islands 101.

[0078] Figure 12 shows an example of a protective strip 108. This strip 108 corresponds, for example, to the example on the left in Figure 10. The protective strip 108 covers a portion of each lower electrode 103 while spanning the structural element 107 that separates these islands 101.

[0079] Figure 13 shows another example of the protective strip 108. This strip 108 may also correspond to the example on the left in Figure 10. In this example, the structural element 107 partially protrudes from each island 101. In particular, the structural element 107 extends from the first lower electrode 103 to the other lower electrode 103 and has an upper surface that forms a gentle slope. The “gentle slope” means a slope measured with respect to the substrate 102 between -45 degrees and 45 degrees, preferably between -20 degrees and +20 degrees, and even more preferably between -5 degrees and +5 degrees. The protective strip 108 covers a portion of each lower electrode 103 and the structural element 107 and also exhibits a gentle slope.

[0080] The protective strip 108 is preferably electrically insulating to prevent short circuits between the lower electrodes 103 of the island 101 connected by the strip 108. The protective strip 108 is made of, for example, aluminum oxide Al2O3, SiO2, or SiN. The protective strip 108 is preferably resistant to etching chemicals of the structural element 107.

[0081] Figures 14 to 16 show the results of partial etching of structural element 107. The etching is performed selectively on the protective strip 108. The etching also includes at least one phase in which the etching is isotropic. The isotropic etching phase removes all portions of structural element 107 that are not protected in particular by the protective strip 108. The trench 106 is therefore partially opened. The etching, and in particular its rate and duration, is shaped to specific dimensions so as to retain only portions 109 of structural element 107 under each protective strip 108, the portions 109 forming supports. Figure 15 shows the results of partial etching compared to Figure 11. In Figure 11 (corresponding to a cross-section along the trench 106), the structural element 107 occupies the entire trench 106. In Figure 15, there are only three supports 109 positioned under each protective strip 108, still within the trench 106. The rest of the trench 106 is void. Partial etching may involve only one etching phase, namely the isotropic etching phase as described herein. However, under certain conditions, isotropic etching can remove portions of structural elements 107 masked by the protective strip 108 very quickly. To remove unmasked portions (e.g., portions exposed in the trench) more quickly, such that only the support 109 beneath the strip 108 is retained, etching may include several etching phases. For example, etching may include at least one anisotropic etching phase and at least one isotropic etching phase, for example, alternating (e.g., anisotropic / isotropic / anisotropic / …). The isotropic etching phases preferably follow the anisotropic etching phases. The anisotropic etching phases are performed with a orientation substantially perpendicular to the substrate. Thus, during these phases, only portions of the exposed (i.e., not masked by the strip) structural elements 107 are etched. During the isotropic phases, portions of the structural elements 107 are etched, even those located beneath the strip 108.The exposed areas are therefore etched during both etching phases, while the masked areas are etched only during the isotropic phase. The etching rate of the exposed areas is therefore increased relative to the etching rate of the masked areas.

[0082] The isotropic phase of partial etching can be carried out in a humid environment using hydrofluoric acid (HF) with concentrations between 0.1% and 2% at room temperature, for example. The isotropic phase can also be carried out by dry isotropic etching using, for example, SF6 (for etching amorphous silicon) or HF (for etching Al2O3 without etching amorphous silicon).

[0083] Partial etching leaves a support 109 beneath each strip 108. Each support 109 of the structural element 107 is defined by its peripheral side surface, also called a "flank." Each support 109 is defined overall by its flank. In the examples of Figures 4 to 16, the flank is - Two surfaces opposite each other and perpendicular to axis Y, and - Similarly, two other surfaces 109a, 109b, which are opposite each other and perpendicular to axis X' (and X), are called "support sides" It has four continuous surfaces, including [the specified surface].

[0084] Two sides 109a and 109b of the column are perpendicular to the trench 106, which extends along direction X'. The surface perpendicular to Y is in contact with island 101, as the structural element 107 first fills the trench 106 separating the two islands. Conversely, the sides 109a and 109b of the column perpendicular to X' and therefore to the trench 106 are free, as they face a portion of the trench 106 that has been removed by etching. Due to the isotropic etching effect, the sides 109a and 109b of the column can have a slightly recessed shape into the column 109.

[0085] Each protective strip 108 also has edges 108a and 108b that extend perpendicular to direction X', that is, perpendicular to the trench 106 over which the protective strip 108 overlaps. The sides 109a and 109b of the support column 109 are substantially perpendicular to the edges 108a and 108b of the protective strip 108 supported by the support column 109.

[0086] Since etching is performed selectively on each protective strip 108, the edges 108a, 108b of the strips remain unchanged (or hardly changed). Partial etching is performed to set back the sides 109a, 109b of each support 109 relative to the edges 108a, 108b of the protective strip 108. Thus, for each strip 108, the sides 109a, 109b of the support 109 that support the strip 108 are set back from the edges 108a, 108b of the strip 108. In this way, the protective strip 108 has two portions 110a, 110b that extend cantilever-like beyond the support 109. The cantilever portions 110a, 110b of the cantilever-type strip 108 are therefore perpendicular to the trench 106, and more specifically, the substrate 102 is exposed within the trench 106 during etching.

[0087] "Setback" refers to a lateral clearance between one of the edges 108a, 108b of the protective strip 108 and the nearest side 109a, 109b of the support 109, measured along direction X' and parallel to the substrate 102. This setback corresponds to the advance of the cantilevered portions 110a, 110b of the protective strip 108. The setback is preferably greater than 100 nm.

[0088] Partial etching of structural element 107 also has the effect of centering each support 109 under the protective strip 108 that each support 109 supports. Thus, each support effectively supports the protective strip 108. The setback of structural element 107 under the protective strip 108 allows for the formation of a bridge that connects the two islands 101 and has cantilever-shaped portions 110a and 110b perpendicular to the substrate 102.

[0089] Figures 18 to 20 show the results of a deposition step, for example by vapor deposition, of an organic layer 201 intended to form the active element of the final pixel of the display 200. The deposited organic material is configured to emit electromagnetic radiation when an electric current passes through it. The emitted radiation may be white, or equivalently red, green, or blue. The organic layer 201 may comprise a single layer configured to emit radiation having a spectrum that is, for example, primarily blue, i.e., a spectrum extending over a wavelength range between 430 nm and 490 nm. Alternatively, the active layer 201 may comprise several emitting sublayers to form a so-called “tandem” OLED structure (not shown). In this case, the organic layer 201 comprises several organometallic sublayers, typically including two emitting organic sublayers separated by charge transport, charge injection, and / or charge generation type organic functional layers located on top of each other. For brevity in the following description, the term “organic layer” is used to mean a homogeneous layer, a stack of organic sublayers, or a stack of organometallic sublayers.

[0090] The organic layer 201 is preferably deposited anisotropically along a direction substantially perpendicular to the substrate 102. By “substantially perpendicular,” it means perpendicular within + / - 20 degrees. The deposition is full wafer deposition. Thanks to the removal of the pillars 109 that support the protective strip, the organic layer 201 is divided into two distinct parts 201-1 and 201-2. The first part 201-1 extends over each island 101 and over the protective strip 108, acting as a bridge and connecting these islands 101. The second part 201-2 of the organic layer 201 extends over the substrate 102 in trenches 106 that are released by partially etching the structural elements 107. The sides 109a, 109b of the pillars 109 are recessed so that the organic material does not accumulate against these sides. The sides 109a and 109b are protected by the cantilevered portions 110a and 110b of the protective strip 108. Therefore, there is no deposition of organic material that could form a link between the two portions 201-1 and 201-2 of the organic layer 201. The cantilevered portions 110a and 110b of the protective strip 108, located vertically above the substrate 102, cause excess organic material to fall into the center of the trench 106 and away from the sides 109a and 109b of the support 109.

[0091] The organic layer 201 can slightly protrude over portions 110a and 110b of the cantilever-type protective strip 108, forming an umbrella that covers the upper portion of the strip 108, as well as the edges 108a and 108b of the strip 108.

[0092] To ensure the separation of portions 201-1 and 201-2 of the organic layer 201, the thickness H201 of the organic layer 201 is preferably less than the height H109 of the support 109. Thus, the second portion 201-2 of the organic layer 201 extending over the substrate 102 does not reach the cantilevered protective strip 108, and in particular its portions 110a and 110b, above the second portion 201-2. In practice, if the thickness reaches the height H109 of the support 109, the organic layer 201 reaches the edge of the protective strip 108. Since the organic material may cover the edge of the strip 108, it is likely that continuity between the two portions 201-1 and 201-2 will be established. To ensure a sufficient margin, the height H109 of the support 109 is preferably 1.2 times greater than the deposition thickness H201 of the organic layer 201, and more preferably 1.4 times greater, or possibly twice as much greater. The deposition thickness H201 is considered equal for both portions 201-1 and 201-2 of the organic layer 201, since both portions 201-1 and 201-2 of the organic layer 201 are deposited in the same step. The measurement of the deposition thickness H201 is preferably performed at a location away from the edges, for example, where this thickness does not vary much. The organic layer 201 preferably has a deposition thickness H201 between 100 nm and 200 nm.

[0093] The previously described steps thus enable the formation of the light-emitting display device 200. In the example of Figures 18 to 20, the device 200 comprises rows of pixels, each row of pixels being formed from a row of islands 101. The pixels are placed on a substrate 102 and comprise a support layer 104, a bottom electrode 103, and an organic layer 201, each extending continuously over the entire row of pixels. In particular, when considering only two of the pixels in the same row of pixels, the device 200 comprises a trench 106 separating the two pixels and a support column 109 located within this trench 106, which electrically insulates the two bottom electrodes 103 of the pixels. The organic layer 201 extends over each bottom electrode 103. A protective strip 108, which forms a bridge connecting the bottom electrodes 103 of the two islands 101 and is supported by the support column 109, thus provides support to the organic layer 201 extending along its entire length over the bottom electrode 103 of each pixel.

[0094] Different rows of pixels in device 200 are separated from one another by trench 106. The cantilevered portions 110a and 110b of strip 108 allow the organic layer to be divided into two distinct portions 201-1 and 201-2 such that portions 201-2 extending into trench 106 are electrically isolated from portions 201-1 extending over island 101.

[0095] To enhance the device 200, an additional step may be performed to deposit an additional conductive layer 204. This additional conductive layer 204 may form an upper electrode for the final pixel. This upper electrode is preferably transmittance or semi-transmissive, regardless of whether the lower electrode 103 is opaque or reflective. The term “semi-transmissive” refers to an element having a light transmittance coefficient between 40% and 60% for at least one wavelength in the spectral band [400nm;1000nm] or possibly [400nm;2000nm].

[0096] Figures 21 and 23 show the results of this additional step. The additional conductive layer 204 is made to have at least one portion 204-1 that completely covers the first portion 201-1 of the organic layer 201. Thus, this portion 204-1 of the additional conductive layer 204 forms the upper electrode of the device 200, and in particular, the upper electrode common to the row of islands 101. Thus, applying a potential between the upper electrode 204-1 and one of the lower electrodes 103 allows an electric field to be applied to the portion of the organic layer positioned between these two electrodes 204-1, 103. The additional conductive layer 204 is formed from, for example, a permeable conductive oxide (TCO) or a semi-permeable thin silver film or a semi-permeable thin aluminum film.

[0097] The deposition of the additional conductive layer 204 is preferably carried out anisotropically in a direction substantially perpendicular to the substrate 102. Similar to the organic layer 201, the additional conductive layer 204 is divided into two separate portions 204-1 and 204-2, separated from each other. The first portion 204-1 extends continuously over the first portion 202 of the organic layer 201 and forms the upper electrode. The second portion 204-2 of the additional conductive layer 204 extends into the trench 106 separating the island row 101 and over the second portion 203 of the organic layer 201.

[0098] To ensure electrical insulation between these two portions 204-1 and 204-2, an additional conductive layer 204 is deposited with a deposition thickness H204 such that the additional conductive layer 204 does not reach the protective strip 108, and in particular the cantilevered portion 110 of the strip 108. For example, the sum of the deposition thickness H201 of the organic layer 201 and the deposition thickness H204 of the additional conductive layer 204 is strictly less than the height H109 of the support pillars 109 that support the protective strip 108. To ensure a sufficient margin, the height H109 of the support pillars 109 is preferably 1.2 times greater than the sum of the thickness H201 of the organic layer 201 and the thickness H204 of the additional conductive layer 204, and more preferably 1.5 times greater than the sum of these thicknesses H201 and H204, or even 2 times greater. In other words, H109 > 1.2 × (H201 + H204), and preferably H109 > 1.5 × (H201 + H204).

[0099] In addition, completing device 200 may involve depositing one or more encapsulation layers to protect easily oxidizable materials. This involves protecting layers formed from, for example, aluminum oxide, silica, or possibly nitrides. For example, one or more encapsulation layers may be formed by single-layer Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD).

[0100] Figures 12 and 13 show two examples of protective strips 108 that can be obtained at the end of the step of forming the strip 108. Figures 12 and 13 show sections made along the rows of island 101, and thus, as each example, show the profile of the strip 108.

[0101] In Figure 12, the structural element 107 forming the base of the strip 108 has a rectangular cross-section. The structural element 107 has two flanks 107a, 107b in particular, each of which is in contact with one of the two islands 101 to be separated. These flanks 107a, 107b extend perpendicular to the substrate 102 until they extend beyond the top of the island 101. The portion of the structural element 107 beyond the island 101 therefore has a stepped shape with abrupt ridges. These ridges do not allow for the formation of the organic layer 201. In fact, the deposition of organic material onto abrupt ridges tends to discontinue the resulting layer. The deposition of organic material onto abrupt ridges therefore no longer forms a continuous layer extending from one island 101 to the other island 101. To mitigate this risk, the organic layer can be made very thick to eliminate the presence of abrupt ridges and discontinuity or cracking. Nevertheless, an excessively thick organic layer tends to reduce the effectiveness of the resulting device 200.

[0102] The protective strip 108 covers the structural element 107 by at least partially removing any abrupt protrusions of the structural element 107. The protective strip 108 is made, for example, by lithography, particularly with a material deposition step. This deposition covers the abrupt protrusions and forms a bridge that overlaps the structural element 107, the free surface of which is "smooth" enough for the organic layer 201 to extend continuously without discontinuity or breaks. "Smooth" means that the tangential free surface to the substrate (also called a "slope," depicted in Figure 12 symbol A1) is between -45° and 45°, preferably between -20° and 20°, and even more preferably between -5° and 5°.

[0103] Figure 13 shows one embodiment modified so that the structural element 107 no longer has abrupt bulges. Thus, the strip 108 extending directly from the structural element 107 has a free surface that extends continuously from one island 101 to another island 101, without edges or discontinuities. This embodiment is very likely to provide a bridge between the two islands, allowing a perfect organic layer to be formed. To obtain this strip 108, the structural element 107 undergoes creep or expansion so that the portion of the element 107 protruding from the islands extends over the edges of these islands 101. This creep or expansion step thus softens or possibly eliminates abrupt bulges. The structural element 107 thus has a gentle slope, allowing the formation of a protective strip 108 with a similarly gentle slope. Creep or expansion can be induced by heat-treating the structural element 107. For example, the structural element 107 is heat-treated at 200°C for 30 minutes to set the deformation irreversibly, and then dried. The strip 108 can be formed in a second step, for example, by lithography.

[0104] Figures 1 to 3 show alternative configurations of the precursor 100 on which the display device 200 is formed. In these alternative configurations, each island 101 comprises a sacrificial layer 105 extending over the lower electrode 103. Each island 101 is formed from a dielectric material such as silicon dioxide (SiO2), aluminum oxide (Al2O3), and preferably silicon nitride (SiN). The silicon nitride (SiN) forms an effective barrier layer for carrying out the polishing step.

[0105] If a sacrificial layer 105 is present, filling the trench 106, which is filled with structural element 107 (as illustrated in Figures 4 to 6), is carried out so that the structural element 107 reaches the top of the sacrificial layer 105. For example, the material intended to form the structural element 107 is a full wafer deposited by filling the trench 106 and covering the island 101. Chemical Mechanical Planarisation (CMP) with the sacrificial layer 105 stopped allows the top of the island 101 to be exposed. Finally, etching of the sacrificial layer 105 following the CMP allows the lower electrode 103 to be removed. This etching of the sacrificial layer 105 is preferably carried out selectively with respect to the structural element 107 and to stop at the conductive layer 103. However, this etching retains the island 101 and, in particular, the portion of the structural element 107 beyond the conductive layer 103.

[0106] The thickness of the sacrificial layer allows for the height H73 of the structural element 107 to be set beyond the lower conductive layer 103. For each island, the sacrificial layer 105 has a thickness between, for example, 10 nm and 100 nm in order to properly perform its role as a stop layer for the CMP step. Therefore, the height H73 can be between 10 nm and 100 nm.

[0107] It is obviously advantageous that the structural element 107 does not protrude from the lower electrode 103. This simplifies the creation of the strip 108 because there are no bulges to be removed. The structural element 107 extending beyond the lower electrode 103 is a result of etching the sacrificial layer 105.

[0108] However, it is also conceivable that the sacrificial layer 105 may be etched non-selectively with respect to the structural element 107. In this case, larger or smaller portions of the structural element 107 are removed simultaneously with the sacrificial layer 105. When the etching rate of the structural element 107 is equal to, for example, the etching rate of the sacrificial layer 105 by up to 10%, the step of the structural element 107 (the portion protruding from the conductive layer 103) is removed simultaneously with the sacrificial layer 105. A step of reduced height may remain. Even so, if the step of reduced height has a height H73 of less than 30 nm, it has no effect on the formation of the organic layer 201.

[0109] In one alternative embodiment, the conductive layer 103 is rigid enough to function as a stopping layer for CMP. In this case, the sacrificial layer 105 is not useful, and the structural element 107 reaches the conductive layer 103 without crossing it. The sacrificial layer 105 may also be sufficiently conductive that it does not need to be removed. The sacrificial layer 105 can therefore be integrated into the final pixel as if it were part of the conductive layer 103.

[0110] In Figures 4 to 9, the structural element 107 is made from an electrical insulating material. Examples include silicon dioxide (SiO2), silicon nitride (SiN), and aluminum oxide (Al2O3). In an alternative embodiment, the structural element 107 may be a polymer-based material such as a resin (particularly for carrying out the step of creeping or expanding the structural element 107). The structural element 107 is more preferably composed of the same electrical insulating material as those mentioned above.

[0111] Filling is carried out, for example, by depositing insulating material to completely fill the trench 106. Filling is carried out, for example, by full wafer deposition of an electrical insulating material (or polymer), followed by polishing (also called "planarization") to stop at a sacrificial layer 105 (preferably of SiN). Before forming the protective strip 108, and assuming that the sacrificial layer 105 is insulating, the sacrificial layer 105 is preferably removed according to the procedure described above.

[0112] Figures 24 to 27 show one alternative embodiment for the manufacturing method, in particular for the structural element 107. The latter is not made from a homogeneous electrical insulating material. The latter includes two materials: a first dielectric material that allows the islands to be electrically insulated from one another, and a second so-called “filling” material that may or may not be insulating, and whose role is to fill the trench 106 to provide support for the protective strip 108. The first dielectric material extends, for example, to each of the islands separated by the structural element.

[0113] Figure 24 shows, for example, the passivation of the precursor 100 in Figures 1 to 3. The passivation layer 112 extends continuously over the islands 101 and into the trenches 106 separating these islands 101. The passivation layer 112 specifically covers the sacrificial layer 105 that extends over the lower electrode 103.

[0114] Figure 25 shows the filling of the passivated trench 106. The filler material 113 is a full wafer deposited to completely fill the trench 106 and extend beyond it.

[0115] Figure 26 shows the stack from Figure 25 being polished and stopping at the sacrificial layer 105. The filler 113 and passivation layer 112 on the outside of the trench 106 are therefore removed. The resulting structural element 107 therefore includes a dielectric layer corresponding to the passivation layer 112, lining the bottom and sides of the trench 106 in a single row, and filler 113 filling the remaining portion of the trench 106.

[0116] Unlike the structural element 107 in Figures 4 to 6, the structural element 107 is not necessarily completely electrically insulating. In practice, the passivation layer 112 is sufficient to provide electrical insulation between the islands 101. The filler 113 is therefore not necessarily insulating. The filler 113 may also be electrically conductive. For example, the filler 113 may be made from amorphous silicon or polycrystalline silicon.

[0117] The step of removing the sacrificial layer 105 is selectively performed on the structural element 107 in Figures 7 to 9. This may also be the case with the structural element 107 in Figure 26. However, in one alternative embodiment illustrated by Figure 27, the removal of the sacrificial layer 105 may be selectively performed on the filler 113 of the structural element 107. Thus, the passivation layer 112 can be removed so that only the filler 113 is exposed. Figure 28 shows an example of a protective strip 108 covering the structural element 107 and, in particular, the filler 113 of this element 107. If the filler 113 is electrically conductive, the protective strip 108 is necessarily electrically insulating.

[0118] Figure 17 shows an alternative embodiment for partial etching of the structural element 107. In practice, etching of the structural element 107 can be performed isotropically and selectively with respect to the protective strip 108 and the lower electrode 103. Thus, the lower electrode 103 remains unchanged, while exposed portions of the support layer 104 (i.e., those that may be exposed to isotropic etching) can be partially etched. After this etching, each support layer 104 thus exhibits a setback D114 relative to the edges 103a, 103b of the lower electrode. Each lower electrode 103 thus has cantilevered portions 114a, 114b. These cantilevers are located vertically above the substrate 102.

[0119] Figures 20 and 23 show the results of the steps for depositing the organic layer 201 and the additional conductive layer 204. Following the same principle as the protective strip 108, the cantilevered portions 114a and 114b allow the organic layer 201 and the conductive layer 204 to be formed by dividing these layers into two distinct portions. Thus, these layers 201 and 204 can be deposited simultaneously on several rows of the island 101 with no electrical contact between the rows. Alternatively, the layers 201 and 204 can extend continuously on each row of the island 101. The deposition thickness H201 and H204 of the layers 201 and 204 is limited so that they cannot reach the lower electrode 103 and, in particular, the cantilevered portions 114 when the layers 201 and 204 form a stack within the trench 106. Therefore, the sum of the depositional thicknesses H201 and H204 is preferably less than the height of the support layer 104 (the latter is usually less than the height of the support column 109).

[0120] The display device 200 resulting from the method detailed above thus comprises several pixels, each having a lower electrode 103 and an organic layer 201 extending over each lower electrode 103. Device 200 is unique in that the organic layer 201 extends continuously over multiple pixels in a single, integrated structure. This is made possible thanks to one or more protective strips 108 that form bridges between the pixels. In a more advanced stage, the multiple pixels may also have a common upper electrode 204 that extends continuously over all pixels in a single, integrated structure, similar to the organic layer 201.

[0121] The protective strip 108, and further the lower electrode 103, have a cantilevered peripheral portion that minimizes the risk of manufacturing defects while mitigating one of the manufacturing limitations, namely the deposition angle of the organic material 201 and the upper electrode 204.

[0122] In the different embodiments described, the island 101 has a separate lower electrode 103. However, several islands may have a common lower electrode 103. For example, in Figure 1, the islands 101 can be grouped by color groups. Islands 101 of the same color can be aligned, for example, by columns, i.e., along the direction Y. In this specification, Figure 1 shows three columns of pixels that may correspond to three distinct colors. At the end of the method, the upper electrode 204 may be common to several islands 101, for example, islands of the same column. The upper electrode 204 extends, for example, continuously along the direction Y. This pixel arrangement is called a “strip” arrangement.

[0123] In one development, the lower electrodes 103 may be formed to extend over several islands 101. However, it is still advantageous that the common lower electrodes 103 do not connect the same islands as the common upper electrodes 204 so that each pixel can be addressed individually. For example, the lower electrodes 103 can connect pixels belonging to different columns. For example, in Figure 1, the islands can be connected by two lower electrodes 103 extending perpendicular to the columns, i.e., along X. One of the lower electrodes 103 connects, for example, three upper islands 101, while the other lower electrode 103 connects three bottommost islands 101. Thus, the common lower electrodes 103 and upper electrodes 204 form a network of crossed electrodes, commonly called a "crossbar," which allows each pixel to be addressed individually.

[0124] The device 200 resulting from the method according to the present invention can conveniently be integrated into a display system such as an electronic device screen, which includes an addressing matrix. The addressing matrix is, for example, partially located on a substrate 102. The addressing matrix is ​​therefore configured to address each lower electrode 103 of a pixel. The addressing matrix includes electrodes that extend into the substrate and open to the surface of the substrate 102 of each support layer 104. The support layer 104, which is conductive or has at least one conductive portion (such as portion 116 in Figures 2 and 3), enables a connection between the lower electrode 103 and the addressing matrix.

[0125] The addressing matrix may also be a so-called "passive" matrix. The addressing matrix may, for example, have multiple intersecting conductions where each pixel is connected at the intersection between two conductions. However, in one favorable development, the intersecting conductions are... - For example, an upper electrode 204 extending along one direction (e.g., Y) and common to several pixels, and - Lower electrode 103 extending perpendicularly to upper electrode 204 (for example, along direction X) and common to several pixels It can be formed by.

[0126] The addressing matrix may also be a so-called "active" matrix. The addressing matrix enables the formation of an AMOLED (Active Matrix Organic Light-Emitting Diode) display system. The active matrix allows each pixel to be controlled independently. The active matrix comprises multiple Thin-Film Transistors (TFTs). Each TFT is connected to a lower pixel electrode 103 so that each pixel can be controlled independently. In one embodiment, an upper electrode 204 is connected to a common cathode, for example, at the edge of the matrix.

Claims

1. A method (300) for manufacturing a light-emitting display device (200) from a precursor (100), wherein the precursor (100) comprises a plurality of islands (101) arranged on a substrate (102), each island (101) comprising a support layer (104) extending on the substrate (102) and a conductive layer (103) extending on the support layer (104), the islands being separated in pairs by trenches (106), and the method (300) is, - Each trench (106) separating the island (101) is filled with a structural element (107) that electrically insulates the island (101), and this is carried out for each trench (106) until the structural element (107) reaches the top of the island (101) separated by the trench (106). - To form at least one protective strip (108), wherein each protective strip (108) connects the two islands (101) by overlapping a trench (102) separating the two islands (101) and by covering a structural element (107) extending within the trench (106), and each protective strip (108) partially covers each of the two islands (101) to which the protective strip (108) connects, - Selectively partially etching structural elements (107) with respect to each protective strip (108) and the conductive layer (103) of the island (101), wherein the partial etching includes at least one isotropic etching phase, and the partial etching is carried out such that only a portion (109) of the structural element (107) located beneath each protective strip (108) is retained, and the portion (109) forms a support for each protective strip (108), and the partial etching is further carried out such that at least one portion (110a, 110b) of each protective strip (108) extends cantilever-like beyond the support (109) that supports that at least one portion (110a, 110b) of the protective strip (108), - Anisotropically depositing an organic layer (201) at an angle substantially perpendicular to the substrate (102), such that the organic layer (201) is divided into two distinct portions (201-1, 201-2), including a first portion (201-1) that extends continuously over each island (101) and each protective strip (108), and a second portion (201-2) that extends over the substrate (102), wherein the deposition thickness of the organic layer (201) is selected such that the second portion (203) of the organic layer (201) does not reach the at least one cantilevered portion (110a, 110b) of each protective strip (108). Method (300), including the method (300).

2. The method according to claim 1 (300), wherein the structural element (107) is partially etched such that the lateral gap (D110) of each protective strip (108) of the at least one cantilever portion (110a, 110b) on the support column (109) that supports the at least one cantilever portion (110a, 110b) is more than 100 nm.

3. The method according to any one of claim 1 or 2 (300), wherein, for each trench (106), filling is carried out to fill the conductive layer (103) of the two islands (101) separated by the trench (106) until the structural element (107) extends beyond a height between 10 nm and 100 nm.

4. The method according to claim 3 (300), wherein each island (101) comprises a sacrificial layer (105) extending over a conductive layer (103) before filling each trench (106), and the filling of each trench (106) with structural elements (107) is carried out such that the structural elements (107) reach the top of the sacrificial layer (105) extending over the island (101).

5. The method according to claim 4 (300), further comprising selectively etching the sacrificial layer (105) of each island (101) with respect to a structural element (107) after filling each trench (106) and before forming each protective strip (108), wherein the etching is carried out such that it stops at the conductive layer (103) of the island (101).

6. Each trench (106) is filled with a structural element (107). - Depositing a layer of electrical insulating material so as to completely fill the trench (106), - Polish the insulating material layer so that it stops at the sacrificial layer (105) of each island (101). The method according to any one of claims 4 or 5 (300), including the method described in claim 4 or 5.

7. Filling each trench (106) with a structural element (107) is done in the following steps: - Conformally depositing a dielectric layer within the trench (106), - Depositing a layer of filler material on the dielectric layer so as to completely fill the trench (106), - Polish the dielectric layer and the packing layer so that they stop at the sacrificial layer (105) of each island (101). The method according to any one of claims 4 or 5 (300), including the method described in claim 4 or 5.

8. The method according to claim 7 (300), wherein the filler is amorphous silicon or polycrystalline silicon.

9. The method according to any one of claims 1 to 8 (300), wherein, before forming each protective strip (108), the structural element (107) is creeped or expanded to form at least one continuous, free surface without bulges extending from the conduction layer (103) of one of the islands (101)(plural), such that the structural element (107) covers a portion of the conduction layer of each island (101), and each free surface has a gradient measured with respect to the substrate (102) between -45 degrees and 45 degrees, preferably between -20 degrees and +20 degrees.

10. The method according to any one of claims 1 to 9 (300), wherein each protective strip (108) is electrically insulating.

11. The method (300) according to any one of claims 1 to 10, wherein the partial etching of the structural element (107) comprises, for example, alternating at least one anisotropic etching phase and at least one isotropic etching phase, each anisotropic etching phase being carried out in a direction substantially perpendicular to the substrate (102).

12. The method (300) according to any one of claims 1 to 11, comprising depositing an organic layer (201), and then anisotropically depositing an additional conductive layer (204) which is distinct from the additional conductive layer (204), comprising a first portion (204-1) of the additional conductive layer (204) extending continuously over a first portion (201-1) of the organic material layer (201), and a second portion (204-2) of the additional conductive layer (204) extending over a second portion (2021-2) of the organic layer (201), wherein the deposition thickness of the additional conductive layer (204) is selected such that the second portion (204-2) of the additional conductive layer (204) does not reach the at least one cantilevered portion (110a, 110b) of each protective strip (108).

13. The method according to any one of claims 1 to 12 (300), wherein the partial etching of the structural element (107) is further carried out to partially etch the support layer (104) of each island (101) such that at least one portion (114) of the conductive layer (103) of the island (101) extends beyond the support layer (104) of the island (101) in a cantilever-like manner.

14. A light-emitting display device (200) comprising a plurality of islands (101) arranged on a substrate (102), wherein each island comprises a support layer (104) extending on the substrate (102) and a conductive layer (103) extending on the support layer (104), and the device, - At least one trench (106) separating the islands (101) into pairs, - At least one protective strip (108), each protective strip (108) overlapping a trench (102) separating two islands (101) connects the two islands (101) to each other, and each protective strip (108) partially covers each of the two islands (101), - At least one support column (109) that at least partially fills the trench and electrically insulates the island (101) separated by the trench (106), wherein each support column (109) reaches or extends beyond the top of the two islands (101) separated by the trench (106), and each support column is positioned below the protective strip (108) to support the protective strip (108) such that at least one portion (110a, 110b) of the protective strip (108) extends beyond the support column (109) in a cantilever-like manner, and - An organic layer (201) having two distinct and separate portions (201-1, 201-2), including a first portion (201-1) that extends continuously over each island (101) and each protective strip (108), and a second portion (201-2) that extends over the substrate (102) without reaching the at least one cantilever-shaped portion (110a, 110b) of each protective strip (108). A light-emitting display device (200) comprising the above.

15. The display device (200) according to claim 14, wherein the lateral gap (D110) of each protective strip (108) between the at least one cantilever-shaped portion (110a, 110b) and the support column (109) that supports the at least one cantilever-shaped portion (110a, 110b) is strictly greater than 100 nm.

16. The display device (200) according to any one of claims 14 or 15, wherein at least one support column (109) is made of an electrically insulating material.

17. The display device (200) according to any one of claims 14 to 16, wherein the at least one support column (109) comprises a dielectric layer for electrically insulating the islands (101) separated by the at least one support column (109) and a filler that functions as a support for a protective strip (108), and the dielectric layer of the at least one support column separates the filler of the at least one support column from each island (101).

18. The display device (200) according to any one of claims 14 to 16, wherein at least one support column (109) has a continuous, smooth surface over which a protective strip (108) extends, the continuous, smooth surface extending from the conductive layer (103) of one of the islands (plural) (101) to the conductive layer of another island (101), and each continuous, smooth surface has a gradient measured with respect to the substrate (102) between -45 degrees and 45 degrees, preferably between -20 degrees and +20 degrees.

19. - A device (200) according to any one of claims 14 to 18, - An active addressing matrix comprising multiple transistors, wherein each of the multiple transistors is connected to the conduction layer (103) of one of the islands (multiple) (101) of the device (200), and A light-emitting display system equipped with the following features.

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