Light-emitting display device, manufacturing method thereof, and light-emitting display system

Abstract

The present invention relates to a method of manufacturing a light emitting display device from a precursor comprising a plurality of island structures disposed on a substrate, each island structure comprising a support layer extending on the substrate; and a conductive layer extending on the support layer, the island structures being separated pairwise by a trench, the method comprising the steps of: filling the trench with an insulating structural element; a protective strip covering only part of each island structure and covering the structural elements; partially etching the structural element, forming a strut below the guard strip, such that the guard strip has an overhanging portion; an organic layer is deposited to form two separate portions: a first portion continuously extending over each island structure and guard strip, and a second portion extending over the substrate. The invention also relates to a light emitting display device comprising at least one trench, at least one protective strip, at least one pillar, and an organic layer. The invention further relates to a light-emitting display system.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic device technology, and specifically relates to a matrix display device with an organic light-emitting layer.

[0002] This invention relates to a method for manufacturing an organic light-emitting diode (OLED) type light-emitting display device, and also to a method for manufacturing such a device.

[0003] This invention can be advantageously applied to the manufacture of electronic device displays, particularly high-resolution color displays, such as active-matrix organic light-emitting diode (AMOLED) displays. In this document, "high resolution" refers to a pixel size of less than 15 micrometers. Background Technology

[0004] In the field of matrix display devices with organic light-emitting layers, OLED-type matrix microdisplays with pixel pitch of less than 20 micrometers (typically between 4 and 12 micrometers) are known.

[0005] When such matrix displays are in color, each pixel is subdivided into subpixels of different colors (typically red, green, and blue). These subpixels work together to emit light of the desired color. The surface shape of a subpixel can be rectangular, square, or other shapes (such as an octagon), and its size may vary depending on the color. Typical subpixel sizes range from 1 micrometer to 20 micrometers.

[0006] Each sub-pixel typically consists of multiple stacked layers, including a lower electrode (anode) deposited on a common substrate, multiple organic layers (at least one of which is a light-emitting layer) formed on each lower electrode to form an OLED stack, and an upper electrode (cathode).

[0007] Patent documents FR3079909A1 and US2023 / 0041252A1 disclose structures for forming such small-sized OLED pixels (or OLED subpixels) with improved industrial reliability.

[0008] The common advantage of these structures is their ability to smoothly discretize OLED stacks and cathodes to form pixels (or subpixels). "Smooth discretization" refers to a structured approach that preserves the performance of OLED stacks.

[0009] Specifically, the solution provided discretizes the OLED stack through a maskless and removal process, since masking and removal processes typically require environments that are harmful to organic materials (humidity, temperatures above 90°C, solvents, ultraviolet light, etc.).

[0010] Therefore, patent document FR3079909A1 discloses a first OLED display device in which the lower electrode of each sub-pixel is separated from each other by an insulating wall that protrudes vertically from the substrate, and each wall acts as a separator between two adjacent sub-pixels.

[0011] The same document FR3079909 also discloses a second device in which the insulating wall is replaced by a trench with an insulating layer deposited on it.

[0012] Insulating walls and trenches are formed before the OLED stacks are deposited via thermal evaporation and serve the same purpose. Because evaporation deposition is primarily directional, the OLED stacks are preferentially deposited on the horizontal walls of the device, rather than on the sidewalls of the insulating walls or trenches. Therefore, the OLED stacks are broken (or discretized) at the insulating walls or trenches.

[0013] However, in practical applications, the directionality of OLED stack deposition is never perfectly ideal. Therefore, organic particles may also deposit on the sidewalls of insulating walls or trenches. These particles are undesirable because they degrade the insulation performance (electrical and optical insulation) between subpixels. Adjacent subpixels may then interfere with each other, for example, through capacitive coupling or parasitic currents. These phenomena, known as crosstalk, can degrade the performance of the display device. These phenomena are exacerbated when the subpixels are so-called "tandem" OLEDs, meaning the subpixels consist of multiple OLED stacks stacked in series via interconnect layers.

[0014] Patent document US2023 / 0041252A1 provides a solution to this problem, disclosing a subpixel separator disposed on a substrate and having a mushroom-shaped structure (or, as used in the document, a "dangling structure"). More specifically, the mushroom-shaped structure includes a lower portion with sloping sides (forming the stem of the mushroom) and an upper portion wider than the lower portion, which covers an area of ​​the substrate. The upper portion forms the cap of the mushroom.

[0015] Subpixels are formed after the mushroom-shaped structure is in place. OLED stacks are then deposited on these structures, with a break at the top. Because organic materials cannot be deposited on the substrate area shielded by the top or on the sidewalls of the mushroom-shaped structure (the lower part cannot be contacted from above due to shielding), the break in the OLED stack has satisfactory reliability. Therefore, the degree of orientation of the OLED stack deposition is irrelevant.

[0016] However, the fabrication of these mushroom-shaped structures is particularly complex and not compact (their vertical height is approximately 1 micrometer). Furthermore, fabricating the common upper electrode (cathode) requires the use of specific equipment to deposit material at a desired angle. In practice, this involves depositing a conductive layer beneath the upper part of the mushroom-shaped structure at a very specific angle, determined by the inclination of the lower part. Therefore, this fabrication method is neither simple nor economically advantageous.

[0017] Therefore, there is still a need for a lower-cost and simpler method for manufacturing high-resolution OLED display devices. Summary of the Invention

[0018] This invention solves the aforementioned problem by utilizing a discrete structure integrated in the lower electrode (typically the anode of the pixel) of a pixel to form a common upper electrode (typically a common cathode) between multiple pixels. To this end, this invention enables the discretization of the lower portions of two adjacent pixels by providing a continuous surface between them to form an organic material layer and a continuous upper electrode.

[0019] One aspect of the present invention relates to a method for manufacturing a light-emitting display device from a precursor, the precursor comprising a plurality of island-shaped structures disposed on a substrate, each island-shaped structure comprising a support layer extending on the substrate and a conductive layer extending on the support layer, the island-shaped structures being separated from each other by trenches, the method comprising the following steps:

[0020] • Fill each trench separating the island structures with structural elements that provide electrical insulation between the island structures, and for each trench, fill until the structural elements reach the top of the island structure separated by the trench;

[0021] • Form at least one protective strip, each protective strip connecting the two island structures to each other by crossing a trench separating the two island structures and covering structural elements extending in the trench, each protective strip only partially covering each of the two island structures it connects to.

[0022] • The structural elements are selectively partially etched relative to the conductive layer of each protective strip and island structure. This partial etching includes at least one isotropic etching stage, proceeding until only a portion of the structural element disposed beneath each protective strip remains, said portion forming a support for each protective strip. The partial etching further proceeds until at least a portion of each protective strip hangs over the support supporting it.

[0023] • An anisotropically deposited organic layer at an angle substantially perpendicular to the substrate, forming two distinct and separate portions of the organic layer, including a first portion extending continuously on each island structure and each protective strip, and a second portion extending on the substrate, wherein the thickness of the organic layer is selected such that the second portion of the organic layer does not reach the at least one overhanging portion of each protective strip.

[0024] Each island structure includes a conductive layer that can form a lower electrode. A support layer for each island structure elevates this conductive layer above the substrate. Guard strips extend from one island structure to another and are supported by insulating elements. Each guard strip forms a bridge between two island structures. This bridge allows for the formation of a continuous, uninterrupted organic layer on the island structures. An additional conductive layer can then be deposited on this organic layer to form a continuous, uninterrupted upper electrode between the island structures. This makes it possible to form a common upper electrode (e.g., a common cathode) for all island structures.

[0025] Removing a portion of the structural elements below each protective strip allows the formation of bridging elements with overhanging portions perpendicular to the substrate within the trench. "Overhanging portions" refer to suspended or unsupported sections. Therefore, there is a discontinuity between the edge of the bridging element and the substrate. Consequently, depositing organic material on the island structures and bridging elements creates two distinct portions of the organic material with no electrical contact between them. During deposition, a portion of the organic material is deposited on each protective strip, particularly the overhanging portions of each strip, while another portion falls onto the substrate between the island structures. The presence of the overhanging portions disrupts the continuity between the protective strips and the substrate. As long as the thickness of the deposited organic material does not allow the portion extending onto the substrate to reach the overhanging portions, the two portions of the organic material (the portions on the bridging elements and island structures, and the portion on the substrate) remain distinct and lack physical and electrical continuity.

[0026] Therefore, it is possible to form an organic layer and electrodes shared by multiple island structures without the risk of short-circuiting with the lower electrode or making electrical contact with surrounding components (such as additional island structures not intended to be connected to these island structures). This enables the manufacture of higher-quality display devices and simplifies the manufacturing process. In fact, even with imperfect directionality, the active elements and upper electrodes of the final pixel can be formed using whole-wafer deposition.

[0027] Furthermore, when the device comprises multiple island-like structures separated from each other by trenches, the island-like structures can be connected in pairs via bridging elements as described above to form a common organic layer and / or a common cathode. No additional separating elements are required to ensure electrical insulation between the final pixels. Therefore, different pixel chains can be formed, each chain having a common cathode. This reduces the number of steps required compared to existing technology solutions. Consequently, this manufacturing method is simpler and faster to execute.

[0028] Advantageously, the step of partially etching structural elements is carried out until the lateral gap between at least one overhang of each protective strip and the support pillar supporting it is strictly greater than 100 nanometers.

[0029] Advantageously, for each trench, the filling extends beyond the conductive layers of the two island structures separated by the trench, with an extension height of 10 nanometers to 100 nanometers.

[0030] Advantageously, before filling each trench, each island structure includes a sacrificial layer extending on the conductive layer, and the step of filling each trench with structural elements is carried out until the structural elements reach the top of the sacrificial layer extending on the island structure.

[0031] Advantageously, the method further includes selectively etching the sacrificial layer of each island structure relative to the structural element after filling each trench and before forming each protective strip, the etching proceeding up to the conductive layer of the island structure.

[0032] Advantageously, for each trench, filling with structural elements includes the following steps:

[0033] • Deposit an electrical insulating material layer to completely fill the trench;

[0034] Polish the electrical insulating material layer until you reach the sacrificial layer of each island structure.

[0035] Advantageously, for each trench, filling with structural elements includes the following steps:

[0036] • A dielectric layer is conformally deposited in the trench;

[0037] • Deposit a filler material layer on the dielectric layer to completely fill the trench;

[0038] Polish the dielectric and filler layers until the sacrificial layer of each island structure is reached.

[0039] Advantageously, the filler material is amorphous silicon or polycrystalline silicon.

[0040] Advantageously, the method includes creeping or expanding the structural elements before forming each protective strip to cover a portion of the conductive layer of each island structure, forming at least one continuous ridgeless free surface extending from the conductive layer of one island structure to the conductive layer of another island structure, each free surface having an inclination angle of -45 degrees to 45 degrees relative to the substrate, preferably -20 degrees to +20 degrees.

[0041] Advantageously, each protective strip is electrically insulated.

[0042] Advantageously, the partially etched structural elements include at least one anisotropic etching stage and at least one isotropic etching stage (e.g., alternating), each anisotropic etching stage being performed in a direction substantially perpendicular to the substrate.

[0043] Advantageously, the method includes anisotropically depositing an additional conductive layer after depositing an organic layer, forming two distinct and separate portions of the additional conductive layer, including a first portion of the additional conductive layer extending continuously over a first portion of the organic material layer, and a second portion of the additional conductive layer extending over a second portion of the organic layer, the deposition thickness of the additional conductive layer being selected such that the second portion of the additional conductive layer does not reach the at least one overhang portion of each protective strip.

[0044] Advantageously, the partial etching of structural elements is further performed to partially etch the support layer of each island structure, such that for each island structure, at least a portion of the conductive layer of the island structure hangs outside the support layer of the island structure.

[0045] Another aspect of the present invention relates to a light-emitting display device comprising a plurality of island-shaped structures disposed on a substrate, each island-shaped structure comprising a support layer extending on the substrate and a conductive layer extending on the support layer, the device comprising:

[0046] • At least one trench that separates two island-like structures;

[0047] • At least one protective strip, each protective strip connecting the two island structures to each other by crossing the trench separating the two island structures and covering the support extending in the trench, each protective strip only partially covering each of the two island structures;

[0048] • At least one support post that at least partially fills a trench and electrically insulates the island structures separated by the trench, each support post reaching or extending beyond the tops of two island structures separated by the trench, each support post being disposed below a protective strip to support the protective strip such that at least a portion of the protective strip hangs over the support post; and

[0049] • An organic layer having two distinct and separate portions, including a first portion extending continuously on each island structure and each protective strip, and a second portion extending on the substrate and not reaching the at least one overhanging portion of each protective strip.

[0050] Advantageously, the lateral gap between the at least one overhanging portion of each protective strip and the support pillar supporting it is strictly greater than 100 nanometers.

[0051] Advantageously, the at least one pillar is made of an electrically insulating material.

[0052] Advantageously, the at least one pillar includes a dielectric layer for electrically insulating the island structures separated by the at least one pillar; and a filler material (insulating or non-insulating) for supporting the protective strip, the dielectric layer of the at least one pillar separating the filler material of the at least one pillar from each island structure.

[0053] Advantageously, the at least one pillar has a continuous ridgeless surface on which a protective strip extends, the continuous ridgeless surface extending from one island-shaped conductive layer to another island-shaped conductive layer, each continuous ridgeless surface having an inclination angle of -45 degrees to 45 degrees relative to the substrate, preferably -20 degrees to +20 degrees.

[0054] The present invention also relates to a light-emitting display system, comprising:

[0055] • The device according to the invention; and

[0056] • An active addressing matrix comprising a plurality of transistors, each of which is connected to a conductive layer of an island structure of the device.

[0057] A better understanding of the invention and its various applications will be gained by reading the following description and referring to the accompanying drawings. Brief description of the attached figures

[0058] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise stated, the same elements appearing in different drawings have the same reference numerals.

[0059] Figures 1, 2, and 3 schematically illustrate an embodiment of a display device precursor according to the present invention in three views.

[0060] Figures 4, 5, and 6 schematically illustrate the first step of the method for manufacturing a display device according to the present invention in three views.

[0061] Figures 7, 8, and 9 schematically illustrate the second step of the method for manufacturing a display device according to the present invention in three views.

[0062] Figures 10 and 11 schematically illustrate examples of protective strips according to the invention in two views.

[0063] Figures 12 and 13 schematically illustrate two more examples of the protective strip according to the invention.

[0064] Figures 14, 15, 16 and 17 schematically illustrate the third step of the method for manufacturing a display device according to the present invention in three views.

[0065] Figures 18, 19, and 20 schematically illustrate the fourth step of the method for manufacturing a display device according to the present invention in three views.

[0066] Figures 21, 22, and 23 schematically illustrate the fifth step of the method for manufacturing a display device according to the present invention in three views.

[0067] Figures 24, 25, 26, 27 and 28 schematically illustrate four steps of an alternative to the manufacturing method according to the invention. Detailed Implementation

[0068] The present invention aims to improve the manufacture of organic light-emitting display devices (also known as organic light-emitting diode (OLED) microdisplays) with improved resolution.

[0069] In the following description, the term "pixel" refers to a subpixel, which is the smallest element that constitutes the 200 pixels of a light-emitting display device.

[0070] The lateral dimension of the pixels is preferably less than 20 micrometers, even less than 10 micrometers, and more preferably 5 micrometers to 1 micrometer, for example, equal to 3 micrometers. For example, their spacing is less than 20 micrometers, for example, 4 micrometers to 12 micrometers. Viewed from above, they have, for example, a rectangular shape with an aspect ratio of approximately 3:1. Pixel size in the following text refers to the side length of a square.

[0071] Therefore, the present invention relates to a method for manufacturing a light-emitting display device from a precursor 100. Examples of the precursor 100 are shown in Figures 1 to 3. These figures show the precursor 100 in particular as a top view (Figure 1) and two cross-sections corresponding to the X and Y directions shown in Figure 1 (Figures 2 and 3).

[0072] In this example, the precursor includes a substrate 102 and a plurality of island structures 101. The island structures 101 are used to form the final pixels of the display device 200. Viewed from above, they have a rectangular shape. Alternatively, they can be square, triangular, hexagonal, circular, or any other shape. They are arranged in pairs on the substrate 101, here in three pairs of island structures. Each pair of island structures forms a column, for example, arranged parallel along the Y direction. The cross-section of a pair of island structures 101 corresponds to the cross-section in Figure 3. The three columns (i.e., three groups of two island structures 101) are distributed along the orthogonal direction X. For example, the island structures 101 can also be arranged along the X direction, thus forming rows of island structures 101. The island structures 101 can be arranged along the X or Y direction with a spacing of less than 20 micrometers, for example, 4 to 12 micrometers. Therefore, groups of island structures can be arranged with a spacing of less than 20 micrometers, for example, 4 to 12 micrometers. Alternatively, the island structures can be arranged in other ways. For example, a group of island structures can be arranged in a hexagonal lattice (also known as a honeycomb lattice). In this case, the spacing is adjusted to correspond to a hexagonal arrangement with a spacing of less than 20 micrometers (e.g., 4 to 12 micrometers).

[0073] The substrate 102 is advantageously a complementary metal-oxide-semiconductor (CMOS) type application-specific circuit or application-specific integrated circuit (ASIC). In this case, the substrate 102 is opaque, and therefore advantageously suitable for manufacturing top-emitting light-emitting display devices. In the following description, the terms "transparent" and "opaque" respectively refer to elements with a light transmittance greater than 60% and less than or equal to 60% for at least one wavelength in the spectral band [400 nm; 1000 nm] or even [400 nm; 2000 nm].

[0074] It should be noted that the substrate 102 may also be made of amorphous silicon, polycrystalline silicon and / or deposited on a glass plate. In the latter case, the substrate 102 may be transparent, thus suitable for manufacturing "bottom-emitting" type light-emitting display devices.

[0075] The substrate 102 includes addressing circuitry (not shown) configured to address the final pixels of the display device 200. The substrate 102 may also include an electrically insulating layer, which may be an oxide, nitride, or oxynitride. For example, the insulating layer is formed of silicon nitride (SiN). The substrate 102 may also include a plurality of contact islands distributed on the insulating layer for electrical contact with the final pixels of the device 200.

[0076] All island structures 101 are separated from each other by at least one trench 106. The trench 106 separates the columns and rows of island structures 101. In other words, within a set of island structures 101, the island structures 101 are separated by trenches 106. Each trench 106 is drilled down from the top of the island structure 101 to the substrate 102. The trench 106 may partially separate the island structures 101, for example, only drilling down to a portion of the height of the island structure (e.g., the island structures 101 may share a bottom portion). The trench 106 may also be drilled into the substrate 102 to improve the insulation of the island structures 101. The island structures 101 may be arranged with a spacing of less than 20 micrometers, for example, from 4 micrometers to 12 micrometers. The width of the trench 106 separating two adjacent island structures 101 is, for example, from 0.3 micrometers to 1.5 micrometers.

[0077] Island structures 101 in the same group (e.g., the same column) are used to form pixels that emit the same wavelength range. The three columns of island structures 101 shown correspond to different wavelengths, for example, to blue, green, and red wavelengths respectively.

[0078] Each island structure 101 has a mesa shape. That is, it is defined by a single wing 112 extending from the substrate 101 to the top of the island structure 101. The wing 112 of the island structure further forms the edge of the groove 106. Viewed from above, the island structure 101 can have a rectangular shape with an aspect ratio of approximately 3:1 (with an error within 10%). The island structure 101 can be square, hexagonal, circular, or similar in shape. When viewed from above (Fig. 1), the surface area of ​​each of them is advantageously less than 40 square micrometers, preferably from 30 square micrometers to 1 square micrometer, for example equal to 5 square micrometers.

[0079] Each island structure 101 includes a support layer 104 extending on a substrate 102. It extends directly abutting the substrate 102, or it can be separated from the substrate 102 by another layer (e.g., a diffusion barrier layer or a layer that promotes the growth of a specific crystal). The thickness H104 of the support layer 104 can be from 150 nanometers to 1000 nanometers. The support layer 104 can be conductive, in which case it can be made of aluminum (Al), aluminum copper alloy (AlCu), chromium (Cr), or even silver (Ag). Alternatively, it can be electrically insulating, in which case it can be made of a dielectric (e.g., silicon oxide (SiO2), silicon nitride (SiN), or aluminum oxide (Al2O3)).

[0080] Each island structure 101 also includes a conductive layer 103. The conductive layer 103 is used to form the electrode of the final pixel, here referred to as the lower electrode. In the following description, the conductive layer 103 may be interchangeably referred to as the "lower electrode". The lower electrode 103 extends on the support layer 104. It extends directly against the support layer 104, or it may be separated from the support layer 104 by another layer (e.g., a diffusion barrier layer or a layer that promotes the growth of a particular crystal). The lower electrode 103 is preferably parallel to the substrate 102.

[0081] For a "top-emitting" type light-emitting display device, the lower electrode 103 can be reflective. The support layer 104 is advantageously reflective or opaque. In top-emitting, all or part of the support layer 104 can also be conductive. The support layer 104 includes, for example, an insulating portion (e.g., surrounding a contact device having a through-hole located directly below the island structure). It can also be conductive. The term "reflective" refers to a surface or element with a light reflectance greater than 60% for at least one wavelength in the spectral band [400 nm; 1000 nm] or even [400 nm; 2000 nm]. For a "bottom-emitting" type light-emitting display device, the lower electrode 103 can be transparent. In this case, the support layer 104 is advantageously transparent. It includes, for example, an insulating portion made of a transparent dielectric material (e.g., surrounding a contact device contacting a through-hole located below the island structure). However, the support layer 104 is advantageously conductive. It includes, for example, means for connecting the island structure to a through-hole located in the substrate 102 (see conductive post 116 described below). It can also be fully conductive.

[0082] The lower electrode 103 may alternatively comprise multiple stacked sublayers. Each sublayer is then formed of a different metallic material or metal alloy. The metallic material (or metal alloy) used to form the first conductive layer 103 preferably has properties that are resistant to the etch chemicals of the support layer 104 and / or structural element 107.

[0083] When the support layer 104 is insulating and includes a dielectric such as SiO2, the lower electrode 103 can be formed of a metallic material or a conductive alloy. The lower electrode 103 may comprise, for example, a stack of conductive layers, such as Ti / TiN / SnO2. In this case, the thickness of the lower electrode 103 is preferably greater than 20 nanometers, and more preferably from 40 nanometers to 100 nanometers. Alternatively, the lower electrode 103 can be formed of a transparent conductive oxide (TCO) to fabricate a bottom-emission type light-emitting display device.

[0084] When the support layer 104 is conductive, the lower electrode 103 is preferably formed of a transparent conductive oxide, such as indium tin oxide (ITO), zinc oxide (ZnO), aluminum-doped zinc oxide (AZO), or tin oxide (SnO2).

[0085] When the current electrode 103 is a stack of conductive sublayers, these sublayers can be formed of titanium nitride (TiN), tin oxide (SnO2), poly(3,4-ethylenedioxythiophene) (PEDOT), ITO, zinc oxide (ZnO), or AZO. Preferably, the sublayer in contact with the organic layer is tin oxide (SnO2), while the sublayer in contact with the support layer 104 is titanium nitride (TiN).

[0086] The thickness of the lower electrode 103 is preferably 4 nm to 20 nm. When it includes a stack of sublayers, the thickness can vary depending on the material. For example, the thickness of the TCO sublayer is 10 nm to 20 nm. The thickness of the TiN sublayer is less than 10 nm, preferably 4 nm to 8 nm.

[0087] The support layer 104 is used 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 fixed on the substrate 102. Therefore, the lower electrode 103 does not directly contact the substrate 102.

[0088] The support layer 104 is at least partially conductive, and therefore also serves to provide electrical connections between the lower electrode 103 and contact pads or vias located directly beneath the island structure (and thus beneath the final pixel). For each island structure 101, if the support layer 104 is not conductive, it may include conductive posts 116 (e.g., posts shown only in Figures 2 and 3) that contact the lower electrode 103 and are 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 fixation of the lower electrode 103.

[0089] For the sake of simplicity, in the following description, unless otherwise stated, only two adjacent island structures 101 in the same column are considered. They correspond, for example, to Figures 3, 6, 9, 12, 13, 16, 19, 22, 24, and 25. Figure 26 The island structures in Figures 27 and 28. In other words, consider two adjacent island structures 101 separated by the same trench 106. The teachings described below can be transposed to columns with more than two island structures 101; simply consider island structures 101 in pairs.

[0090] Figures 4 through 9 illustrate the steps of filling the trench 106 separating the two island structures 101 with structural element 107. Thus, the structural element 107 separates the two island structures 101 while ensuring electrical insulation between them. Structural element 107 preferably completely fills the entire trench 106 and is in direct contact with the two island structures 101.

[0091] At the end of the filling process, the structural element 107 reaches the top of the two island structures 101. In other words, the height H107 of the structural element 107 (perpendicular to and measured from the substrate 102) is greater than or equal to (and preferably equal to) the height H101 of the island structures 101. The height H101 is measured, for example, from the substrate 102 to the top of each island structure 101.

[0092] In one embodiment, the step of filling trench 106 proceeds until the conductive layer 103 is reached. "Reaching the conductive layer" means that the height of the structural element 107 (measured from the substrate 102) allows it to directly contact the conductive layer 103. In other words, the structural element 107 is flush with or extends beyond the conductive layer 103. Preferably, the structural element 107 is flush with the conductive layer 103.

[0093] In an alternative to this method (described in detail below), the island structure 101 may include a sacrificial layer 105, thereby increasing the total height H101 of each island structure 101. In the presence of the sacrificial layer 105, the step of filling the trench 106 proceeds to the top of the island structure 101, i.e., the top of the sacrificial layer 105. From there, the structural element 107 extends beyond the conductive layer 103.

[0094] 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 may be non-planar and have different heights. In this case, the height is compared with the vertical direction of the side wings 112 of the island structure 101 (especially with respect to the vertical direction of the portion in contact with the structural element 107).

[0095] Figures 10 to 13 illustrate the protective strip 108. The protective strip 108 forms a bridge between two island structures 101 in the same column. Therefore, it is able to support a continuously extending organic material layer that completely covers the two island structures 101.

[0096] Therefore, the protective strip 108 is a single continuous layer, without breaks or cuts, extending from one island structure 101 to another. The protective strip 108 only covers a portion of each island structure 101. In this way, the organic material layer can directly contact the rest of each lower electrode 103.

[0097] The protective strip 108 also extends onto the structural element 107 separating the two island structures to at least cover a portion of it. Figure 10 shows three examples of the protective strip 108. According to the first preferred example, in the first column (left column), the protective strip 108 extends onto a portion of the lower electrode 103 of one island structure 101 and extends along the Y direction to the other island structure 101 in the same column. The mask 108 covers only a small portion of each island structure 101 and a small portion of the structural element 107. According to the second example, in the second column (middle column), the protective strip 108 extends onto a larger portion of each lower electrode 103, partially penetrating the surface of these electrodes. According to the third example, in the third column (right column), the protective strip 108, as an extension of the two island structures 101, completely covers the structural element 107 separating the two island structures 101. Figure 11 shows cross-sections of these different examples.

[0098] The protective strip 108 forms a bridging element that allows the deposition of continuous material layers on two adjacent island structures 101. It may be necessary to form continuous layers on more than two island structures 101, for example, connecting all island structures belonging to the same column of island structures 101. In this case, multiple protective strips 108 can be formed, each covering two adjacent island structures 101 and the structural elements 107 separating them.

[0099] It may be advantageous for each protective strip 108 to be limited to only two adjacent island structures 101 (and associated structural elements 107). However, in order to form a continuous layer on more than two island structures 101, the protective strips may be formed to cover each of these island structures 101 while maintaining a continuous overall layer. Alternatively, it may be preferable for each protective strip 108 to be limited to only two island structures 101 (and associated structural elements 107), and strictly limited to these two island structures 101.

[0100] 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 and spans across the structural element 107 that separates these island structures 101.

[0101] Figure 13 shows another example of the protective strip 108. This strip 108 can also correspond to the example on the left in Figure 10. In this example, the structural element 107 partially protrudes from each island structure 101. In particular, it has an upper surface that extends from the first lower electrode 103 to the other lower electrode and forms a gently sloping surface. "Gently sloping" refers to a tilt angle of -45 degrees to 45 degrees relative to the substrate 102, preferably -20 degrees to +20 degrees, and even more preferably -5 degrees to +5 degrees. The protective strip 108, covering a portion of each lower electrode 103 and the structural element 107, also exhibits a gently sloping surface.

[0102] The protective strip 108 is preferably electrically insulating to prevent short circuits between the lower electrodes 103 of the island structure 101 connected by the strip 108. It is made, for example, of alumina (Al2O3), silicon oxide (SiO2), or silicon nitride (SiN). It is preferably made of a material resistant to etching chemicals of the structural element 107.

[0103] Figures 14 to 16 show the results of partial etching of structural element 107. The etching is performed selectively relative to the protective strip 108. It also includes at least one isotropic etching stage. The isotropic etching stage removes all unprotected portions of structural element 107 (particularly those not protected by the protective strip 108). Thus, trench 106 is partially released. The etching (particularly its rate and duration) is set to retain only a portion 109 of structural element 107 below each protective strip 108, which forms a pillar. Figure 15 shows the partial etching results relative to Figure 11. In Figure 11 (corresponding to a cross-section along trench 106), structural element 107 occupies the entire trench 106. Figure 15In this process, only three pillars 109 are retained, located below each protective strip 108, remaining in the trench 106. The rest of the trench 106 is empty. Partial etching may consist of only one etching stage, here an isotropic etching stage. However, under certain conditions, isotropic etching may remove portions of the structural element 107 masked by the protective strips 108 too quickly. To remove unmasked portions (e.g., exposed portions in the trench) more quickly, so that only the pillars 109 below the strips 108 are retained, etching may include multiple etching stages. For example, it includes at least one anisotropic etching stage and at least one isotropic etching stage (e.g., alternating, e.g., anisotropic / isotropic / anisotropic / …). The anisotropic etching stage is preferably performed after the isotropic etching stage. The anisotropic etching stages are performed with a orientation generally perpendicular to the substrate. Therefore, in these stages, only the exposed portions of the structural element 107 (i.e., the portions not masked by the strips) are etched. In the isotropic stage, even portions of the structural element 107 located below the strip 108 are etched. Therefore, the exposed portions are etched in both etching stages, while the masked portions are etched only in the isotropic stage. Consequently, the etching rate of the exposed portions is higher than that of the masked portions.

[0104] The isotropic phase of partial etching can be performed in a wet environment, for example using hydrofluoric acid (HF) at a concentration of 0.1% to 2% at room temperature. The isotropic phase can also be performed by dry isotropic etching, for example using sulfur hexafluoride (SF6, used for etching amorphous silicon) or hydrofluoric acid (HF, used for etching alumina without etching amorphous silicon).

[0105] Partial etching leaves struts 109 beneath each strip 108. Each strut 109 of the structural element 107 is defined by a peripheral side (also referred to as a "flank"). Each strut 109 is entirely defined by a flank. In the example of Figures 4 through 16, the flank comprises four continuous surfaces, including:

[0106] • Two surfaces facing each other and perpendicular to the Y-axis; and

[0107] • Two other surfaces 109a and 109b that are opposite each other and perpendicular to the X' axis (and the X axis) (referred to as "pillar sides").

[0108] The two side surfaces 109a and 109b of the struts are also perpendicular to the trench 106, which extends along the X' direction. Since the structural element 107 initially fills the trench 106 separating the two island structures, the surface perpendicular to the Y-axis contacts the island structure 101. Conversely, the side surfaces of the struts 109a and 109b, perpendicular to the X' axis (and therefore perpendicular to the trench 106), are free because they face the portion of the trench 106 that has been cleaned by etching. Due to the isotropic etching effect, the side surfaces of the struts 109a and 109b may have a concave shape, slightly extending into the strut 109.

[0109] Each protective strip 108 also has edges 108a, 108b extending perpendicular to the X' direction (i.e., perpendicular to the groove 106 it overlaps). The sides 109a, 109b of the support 109 are generally perpendicular to the edges 108a, 108b of the protective strip 108 supported by the support 109.

[0110] Because etching is performed selectively relative to each protective strip 108, the edges 108a, 108b of the strips 108 remain intact (or with minimal variation). Partial etching causes the sides 109a, 109b of each support 109 to be recessed relative to the edges 108a, 108b of the protective strips 108. Therefore, for each strip 108, the sides 109a, 109b of the supports 109 that support the strip 108 are positioned at the recessed (set back) edges 108a, 108b of the strip 108. Thus, the protective strip 108 has two overhanging portions 110a, 110b extending beyond the supports 109. The overhanging portions 110a, 110b of the overhanging strips 108 are therefore perpendicular to the trench 106, and more specifically, perpendicular to the substrate 102 exposed in the trench 106 during etching.

[0111] "Setback" refers to the lateral distance between one of the edges 108a and 108b of the protective strip 108, measured along the X' direction and parallel to the substrate 102, and the nearest sides 109a and 109b of the support 109. This setback corresponds to the advancement of the overhanging portions 110a and 110b of the protective strip 108. The setback is preferably greater than 100 nanometers.

[0112] The partially etched structural element 107 also has the effect of centering each pillar 109 below the protective strip 108 it supports. Thus, each pillar effectively supports the protective strip 108. The indentation of the structural element 107 below the protective strip 108 allows for the formation of a bridging element connecting the two island structures 101 and having overhanging portions 110a, 110b above the substrate 102.

[0113] Figures 18 through 20 illustrate the results of a deposition step (e.g., by evaporation) that deposits an organic layer 201 for forming the active elements of the final pixels of display 200. The deposited organic material is configured to generate electromagnetic radiation when an electric current passes through it. The emitted radiation can be white or equivalent red, green, or blue. Organic layer 201 may comprise a single layer configured to emit radiation whose spectrum is predominantly in the blue region (i.e., a wavelength range between 430 nm and 490 nm). Alternatively, active layer 201 may comprise multiple emitting sublayers to form a so-called “tandem” OLED structure (not shown). In this case, organic layer 201 comprises multiple organometallic sublayers, typically including two vertically arranged emitting organic sublayers separated by an organic functional layer of the charge transport, charge injection, and / or charge generation type. In the following description, for simplicity, the term “organic layer” is used to refer to a homogeneous layer, a stack of organic sublayers, or a stack of organometallic sublayers.

[0114] The organic layer 201 is preferably deposited anisotropically in a direction substantially perpendicular to the substrate 102. "Substantially perpendicular" means perpendicular with an error within + / - 20 degrees. The deposition is performed on the entire wafer. Due to the removal of the support pillars 109 that support the guard strips, the organic layer 201 is split into two distinct portions 201-1 and 201-2. The first portion 201-1 extends over each island structure 101 and the guard strip 108, acting as a bridge and connecting these island structures 101. The second portion 201-2 of the organic layer 201 extends over the substrate 102, located in the trench 106 released by partially etching the structural elements 107. Because the sides 109a, 109b of the support pillars 109 are recessed, no organic material accumulates on these sides. The sides 109a, 109b are protected by the overhanging portions 110a, 110b of the guard strip 108. Therefore, no organic material that could form a connector between the two portions 201-1 and 201-2 of the organic layer 201 will be deposited. The overhanging portions 110a and 110b of the protective strip 108 are perpendicular to the substrate 102, causing excess organic material to fall into the center of the trench 106, away from the sides 109a and 109b of the pillar 109.

[0115] The organic layer 201 may protrude slightly onto portions 110a and 110b of the overhanging protective strip 108, forming a cap-like structure covering the upper part of the strip 108 and the edges 108a and 108b of the strip 108.

[0116] To ensure 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 pillar 109. This prevents the second portion 201-2 of the organic layer 201 extending onto the substrate 102 from reaching the protective strip 108, particularly the portions 110a and 110b that hang above the second portion 201-2. In practice, if the thickness reaches the height H109 of the pillar 109, the organic layer 201 will subsequently reach the edge of the protective strip 108. Since the organic material can cover the edge of the strip 108, it is likely that continuity can be established between the two portions 201-1 and 201-2. To ensure sufficient margin, the height H109 of the pillar 109 is preferably greater than 1.2 times, even more preferably greater than 1.4 times, or even greater than 2 times, the deposition thickness H201 of the organic layer 201. The deposition thickness H201 of the two portions 201-1 and 201-2 of the organic layer 201 is considered to be equal because these two portions 201-1 and 201-2 are deposited in the same step. The measurement of the deposition thickness H201 is preferably performed at a location where the thickness variation is small, such as away from the edge. The deposition thickness H201 of the organic layer 201 is preferably 100 nm to 200 nm.

[0117] The above steps thus enable the formation of a light-emitting display device 200. In the example of Figures 18 to 20, device 200 includes a pixel column, each pixel column being formed by a column of island structures 101. Pixels are disposed on a substrate 102, and each pixel includes a support layer 104, a lower electrode 103, and an organic layer 201 continuously extending over the entire pixel column. Specifically, considering only two pixels in the same pixel column, device 200 includes a trench 106 separating the two pixels and a pillar 109 disposed in the trench 106 and electrically insulating the two lower electrodes 103 of the pixel. The organic layer 201 extends over each lower electrode 103. A protective strip 108 is formed connecting the lower electrodes 103 of the two island structures 101 and supported by the pillar 109, thereby providing support for the organic layer 201, which extends along its entire length over the lower electrode 103 of each pixel.

[0118] Different pixel columns of device 200 are separated from each other by trench 106. Overhanging portions 110a, 110b of strip 108 allow the organic layer to be split into two distinct separate portions 201-1, 201-2, such that portion 201-2 extending into trench 106 is electrically insulated from portion 201-1 extending on island structure 101.

[0119] To enhance the device 200, an additional step of depositing an additional conductive layer 204 may be performed. This additional conductive layer 204 may form the upper electrode of the final pixel. Regardless of whether the lower electrode 103 is opaque or reflective, the upper electrode is preferably transparent or translucent. The term "translucent" refers to a component with a light transmittance of 40% to 60% for at least one wavelength in the spectral band [400 nm; 1000 nm] or even [400 nm; 2000 nm].

[0120] Figures 21 and 23 illustrate the result of this additional step. The additional conductive layer 204 is formed as a portion 204-1 having at least one first portion 201-1 completely covering the organic layer 201. Therefore, this portion 204-1 of the additional conductive layer 204 forms the upper electrode of the apparatus 200, particularly the upper electrode shared by the island-like structures 101. Thus, by applying a potential between the upper electrode 204-1 and a lower electrode 103, an electric field can be applied to a portion of the organic layer disposed between these two electrodes 204-1, 103. The additional conductive layer 204 is formed, for example, from a transparent conductive oxide (TCO), a translucent thin silver film, or a translucent thin aluminum film.

[0121] The deposition of the additional conductive layer 204 is preferably performed anisotropically in a direction substantially perpendicular to the substrate 102. Similar to the organic layer 201, the additional conductive layer 204 is split into two distinct and separate portions 204-1 and 204-2. The first portion 204-1 extends continuously on 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 trenches 106 of the separating island-like structure array 101 and extends on the second portion 203 of the organic layer 201.

[0122] To ensure electrical insulation between the two portions 204-1 and 204-2, the deposition of the additional conductive layer 204 is carried out with a deposition thickness H204, such that the additional conductive layer 204 does not reach the protective strip 108, particularly the overhang 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 post 109 supporting the protective strip 108. To ensure sufficient margin, the height H109 of the support post 109 is preferably greater than 1.2 times, even more preferably greater than 1.5 times, or even greater than 2 times, the sum of the thickness H201 of the organic layer 201 and the thickness H204 of the additional conductive layer 204. In other words, H109 > 1.2 × (H201 + H204), and preferably H109 > 1.5 × (H201 + H204).

[0123] As a supplement, the finishing device 200 may include depositing one or more encapsulation layers for protecting oxidizable materials. For example, this involves protecting layers formed of alumina, silicon dioxide, or even nitrides. The encapsulation layers are formed, for example, by atomic layer deposition (ALD) or chemical vapor deposition (CVD).

[0124] Figures 12 and 13 show two examples of the protective strip 108 that can be obtained at the end of the step of forming the strip 108. Figures 12 and 13 show cross-sections taken along a row of island structures 101, thus showing the outline of the strip 108 in each example.

[0125] In the case of Figure 12, the structural element 107 below the strip 108 has a rectangular cross-section. The structural element 107 specifically includes two flanks 107a and 107b, each flank contacting one of the two island structures 101 to be separated. These flanks 107a and 107b extend perpendicularly to the substrate 102 beyond the top of the island structure 101. The portion of the structural element 107 extending beyond the island structure 101 thus has a stepped shape with sharp ridges. These ridges do not allow for the formation of the organic layer 201. In fact, depositing organic material on sharp ridges often leads to fracture of the resulting layer. Therefore, it no longer forms a continuous layer extending from one island structure 101 to the other. To mitigate this risk, the organic layer can be made very thick to eliminate the presence of sharp ridges and fractures or breaks. However, an excessively thick organic layer often reduces the effectiveness of the resulting device 200.

[0126] The protective strip 108 covers the structural element 107 by at least partially eliminating the sharp ridges of the structural element 107. The protective strip 108 is manufactured, for example, by photolithography, specifically including a material deposition step. This deposition covers the sharp ridges and forms a bridging element across the structural element 107, the free surface of which is sufficiently "smooth" so that the organic layer 201 can extend continuously without breaks or cuts. "Smooth" means that the free surface has a tangent (also called "tilt," indicated by symbol A1 in FIG. 12) of -45° to 45°, preferably -20° to 20°, and even more preferably -5° to 5°.

[0127] Figure 13 illustrates an embodiment in which structural element 107 is modified to no longer have sharp ridges. Therefore, the strip 108 extending directly abutting structural element 107 has a free surface extending continuously from one island structure 101 to another, without edges or breaks. This embodiment most likely provides a bridging element between two island structures, allowing for the formation of a defect-free organic layer. To obtain this strip 108, structural element 107 undergoes creep or expansion, causing portions of element 107 that protrude from the island structures onto the edges of these island structures 101 to extend outwards. This creep or expansion step thus softens or even eliminates sharp ridges. Structural element 107 thus has a gentle slope, allowing for the formation of a protective strip 108 with a similar gentle slope. Creep or expansion can be achieved by heat-treating structural element 107. For example, structural element 107 is heat-treated at 200°C for 30 minutes and then dried to irreversibly fix the deformation. Strip 108 can be formed in the second step, for example by photolithography.

[0128] Figures 1 through 3 illustrate an alternative to the precursor 100 from which the display device 200 is formed. In this alternative, each island structure 101 includes a sacrificial layer 105 extending on a lower electrode 103. It is formed, for example, of a dielectric material such as silicon oxide (SiO2), aluminum oxide (Al2O3), and preferably silicon nitride (SiN). The silicon nitride (SiN) forms an effective barrier layer for performing polishing steps.

[0129] In the presence of the sacrificial layer 105, the step of filling the trench 106 with structural elements 107 (as shown in Figures 4 to 6) proceeds until the structural elements 107 reach the top of the sacrificial layer 105. For example, the material used to form the structural elements 107 is deposited over an entire wafer to fill the trench 106 and cover the island structure 101. Chemical mechanical planarization (CMP) with the sacrificial layer 105 as a stop layer allows the top of the island structure 101 to be exposed. Finally, etching of the sacrificial layer 105 after CMP allows the cleaning of the lower electrode 103. This etching of the sacrificial layer 105 is preferably performed selectively relative to the structural elements 107 and with the conductive layer 103 as a stop layer. However, this etching preserves a portion of the structural elements 107 that extends beyond the island structure 101, particularly the conductive layer 103.

[0130] The thickness of the sacrificial layer allows the height H73 of the structural element 107 to exceed the height of the lower conductive layer 103. For each island structure, the thickness of the sacrificial layer 105 is, for example, 10 nm to 100 nm, to properly perform the function of the stop layer in the CMP step. Therefore, the height H73 can be 10 nm to 100 nm.

[0131] Structural element 107 preferably does not protrude beyond the lower electrode 103. Therefore, there is no ridge to eliminate, and the fabrication of strip 108 is simplified. The structural element 107 extending beyond the lower electrode 103 is a result of etching the sacrificial layer 105.

[0132] However, it is possible to non-selectively etch the sacrificial layer 105 relative to the structural element 107. In this case, more or less of the structural element 107 is removed simultaneously with the sacrificial layer 105. When the etching rate of the structural element 107 is equal to the etching rate of the sacrificial layer 105 (e.g., with an error within 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 with reduced height may remain. However, if its height H73 is less than 30 nm, it has no effect on the formation of the organic layer 201.

[0133] In an alternative, the conductive layer 103 is rigid enough to act as a stop layer for CMP. In this case, the sacrificial layer 105 is unnecessary, and the structural elements 107 reach the conductive layer 103 without extending beyond it. The sacrificial layer 105 can also be conductive enough that it does not need to be removed. Therefore, they can be integrated into the final pixel as if they were part of the conductive layer 103.

[0134] In Figures 4 through 9, structural element 107 is made of an electrically insulating material. Examples include silicon oxide (SiO2), silicon nitride (SiN), and aluminum oxide (Al2O3). Alternatively, structural element 107 can be a polymer-based material, such as a resin (particularly for performing the creep or expansion steps of structural element 107). Structural element 107 is even more preferably composed of the same electrically insulating materials as those described above.

[0135] Filling is performed, for example, by depositing an insulating material to completely fill trench 106. Filling is achieved, for example, by depositing an electrically insulating material (or polymer) over an entire wafer, followed by polishing (also known as "planarization") with a sacrificial layer 105 (preferably SiN) as a stop layer. Before forming the guard strip 108, and assuming that the sacrificial layer 105 is insulating, the sacrificial layer 105 is preferably removed according to the previously described procedure.

[0136] Figures 24 through 27 illustrate an alternative manufacturing method, particularly an alternative to structural element 107. The latter is not made of a homogeneous electrically insulating material. It comprises two materials: a first dielectric material that allows the island structures to be electrically insulated from each other; and a second so-called “filler” material (which may be insulating or non-insulating) that fills the trench 106 to support the protective strip 108. The first dielectric material extends, for example, against each island structure separated by the structural element.

[0137] Figure 24 illustrates the passivation of a precursor 100, such as those in Figures 1 through 3. A passivation layer 112 extends continuously over the island structures 101 and in the trenches 106 separating these island structures 101. The passivation layer 112 specifically covers the sacrificial layer 105 extending over the lower electrode 103.

[0138] Figure 25 shows the filled passivated trench 106. The filler material 113 is deposited over the entire wafer to completely fill the trench 106 and extend beyond its boundaries.

[0139] Figure 26 shows the stack of polished Figure 25, with sacrificial layer 105 as the stop layer. Therefore, the filler material 113 and passivation layer 112 outside the trench 106 are removed. The resulting structural element 107 then includes: a dielectric layer (corresponding to the passivation layer 112, lining the bottom and sides of the trench 106); and filler material 113 filling the remainder of the trench 106.

[0140] Unlike structural element 107 in Figures 4 through 6, structural element 107 is not necessarily completely electrically insulating. In fact, the passivation layer 112 is sufficient to achieve electrical insulation between the island structures 101. Therefore, the filler material 113 is not necessarily insulating. It can also be conductive. For example, it can be made of amorphous silicon or polycrystalline silicon.

[0141] In Figures 7 through 9, the removal of the sacrificial layer 105 is performed selectively relative to the structural element 107. This may also be the case for the structural element 107 in Figure 26. However, in an alternative shown in Figure 27, the removal of the sacrificial layer 105 can be performed selectively relative to the filler material 113 of the structural element 107. Therefore, the passivation layer 112 can be removed only, leaving the filler material 113 exposed. Figure 28 shows an example of a protective strip 108 covering the structural element 107 (particularly the filler material 113 of the element 107). If the filler material 113 is conductive, the protective strip 108 must be electrically insulating.

[0142] Figure 17 illustrates an alternative embodiment of partially etched structural element 107. In practice, the etching of structural element 107 can be performed isotropically and selectively relative to the guard strip 108 and the lower electrode 103. Thus, the lower electrode 103 remains intact, while exposed portions of the support layer 104 (i.e., portions potentially exposed to isotropic etching) can also be partially etched. Following this etching, each support layer 104 then presents a recess D114 relative to the edges 103a, 103b of the lower electrode. Each lower electrode 103 then has overhanging portions 114a, 114b. These overhanging portions are perpendicular to the substrate 102.

[0143] Figures 20 and 23 illustrate the results of the steps of depositing the organic layer 201 and the additional conductive layer 204. Following the same principle as the protective strip 108, the overhangs 114a and 114b allow the organic layer 201 and the conductive layer 204 to be formed by splitting these layers into two distinct portions. Therefore, these layers 201 and 204 can be deposited simultaneously on the multi-row island structure 101 without electrical contact between the rows. Alternatively, layers 201 and 204 can extend continuously on each row of island structures 101. The deposition thicknesses H201 and H204 of layers 201 and 204 are limited such that they cannot reach the lower electrode 103, particularly the overhangs 114, when they form a stack in the trench 106. Therefore, the sum of the deposition thicknesses H201 and H204 is preferably strictly less than the height of the support layer 104 (which is typically less than the height of the pillar 109).

[0144] The display device 200 obtained by the detailed method described above thus includes a plurality of pixels, each pixel including a lower electrode 103 and an organic layer 201 extending on each lower electrode 103. The device 200 is unique in that the organic layer 201 extends continuously on the plurality of pixels in a monolithic form. This is achieved by one or more protective strips 108 forming bridging elements between the pixels. At a more advanced stage, the plurality of pixels may also have an upper electrode 204 shared by all pixels, which, like the organic layer 201, extends continuously on the plurality of pixels in a monolithic form.

[0145] The protective strips (multiple) 108, and even the lower electrode 103, have overhanging peripheral portions, which minimizes the risk of manufacturing defects while relaxing one of the manufacturing limitations, namely the deposition angle of the organic material 201 and the upper electrode 204.

[0146] In the different embodiments described, the island structures 101 have different lower electrodes 103. However, some island structures may share a common lower electrode 103. For example, in FIG1, the island structures 101 may be grouped by color. For example, island structures 101 of the same color may be arranged in columns, i.e., along the Y direction. Here, FIG1 shows three columns of pixels, which may correspond to three different colors. At the end of the method, the upper electrode 204 may be shared by multiple island structures 101 (e.g., island structures in the same column). The upper electrode 204 may extend continuously, for example, along the Y direction. This pixel arrangement is called a "strip" arrangement.

[0147] In an improved embodiment, the lower electrode 103 can be formed extending over multiple island structures 101. However, in order to address each pixel individually, the common lower electrode 103 preferably does not connect to the same island structure as the common upper electrode 204. For example, the lower electrode 103 can connect pixels belonging to different columns. For example, in FIG1, the island structures can be connected by two lower electrodes 103 extending perpendicular to the column (i.e., extending along the X direction). For example, one lower electrode 103 connects three upper island structures 101, while the other lower electrode 103 connects three lower island structures 101. Therefore, the common lower electrode 103 and the upper electrode 204 form a cross electrode network (commonly referred to as a "crossbar"), allowing pixel addressing one by one.

[0148] The device 200 obtained by the method according to the invention can be advantageously integrated into a display system (such as an electronic device screen) including an addressing matrix. The addressing matrix is, for example, partially disposed in a substrate 102. It is then configured to address each lower electrode 103 of a pixel. It includes, for example, electrodes extending into the substrate and opening on the surface of the substrate 102, each support layer 104. The support layer 104 (which is conductive or includes at least one conductive portion (such as portion 116 in Figures 2 and 3)) enables the connection between the lower electrode 103 and the addressing matrix.

[0149] The addressing matrix can be a so-called "passive" matrix. It may include, for example, multiple intersecting conductive lines, with each pixel connected at the intersection between two conductive lines. However, in an advantageous improvement, the intersecting conductive lines can consist of the following:

[0150] • The upper electrode 204 extends, for example, along a direction (e.g., the Y direction) and is shared by multiple pixels; and

[0151] The lower electrode 103 extends perpendicularly to the upper electrode 204 (e.g., along the X direction) and is shared by multiple pixels.

[0152] The addressing matrix can be a so-called "active" matrix. It allows for the formation of an active matrix organic light-emitting diode (AMOLED) display system. An active matrix allows each pixel to be controlled independently. It includes multiple thin-film transistors (TFTs). Each TFT is connected to the lower electrode 103 of the pixel, enabling each pixel to be controlled independently. In one embodiment, the 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), said precursor (100) comprising a plurality of island structures (101) disposed on a substrate (102), each island structure (101) comprising a support layer (104) extending on the substrate (102); and a conductive layer (103) extending on the support layer (104), the island structures being separated from each other by trenches (106), said method (300) comprising the following steps: • Fill the trench (106) separating each island structure (101) with a structural element (107) that electrically insulates the island structure (101), and for each trench (106), the filling is carried out until the structural element (107) reaches the top of the island structure (101) separated by the trench; • Form at least one protective strip (108), each protective strip (108) connecting the two island structures (101) to each other by crossing the trench (102) separating the two island structures (101) and covering the structural element (107) extending in the trench (106), each protective strip (108) only partially covering each of the two island structures (101) to which it is connected; • The structural elements (107) of each protective strip (108) and island structure (101) are selectively partially etched relative to the conductive layer (103). This partial etching includes at least one isotropic etching stage, proceeding to retain only a portion (109) of the structural element (107) disposed beneath each protective strip (108), said portion (109) forming a support for each protective strip (108). The partial etching further proceeds to at least a portion (110a, 110b) of each protective strip (108) extending overhangingly beyond the support (109) supporting it; and • An anisotropically deposited organic layer (201) at an angle substantially perpendicular to the substrate (102) forms two distinct and separate portions (201-1, 201-2) of the organic layer (201), including a first portion (201-1) extending continuously on each island structure (101) and each protective strip (108), and a second portion (201-2) extending on the substrate (102). 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 overhang portion (110a, 110b) of each protective strip (108).

2. The method (300) according to claim 1, characterized in that, The step of partially etching structural elements (107) is carried out until the lateral gap (D110) between the at least one overhanging portion (110a, 110b) of each protective strip (108) and the support pillar (109) supporting it is strictly greater than 100 nanometers.

3. The method (300) according to claim 1 or 2, characterized in that, For each trench (106), filling is carried out until the structural element (107) extends beyond the conductive layer (103) of the two island structures (101) separated by the trench, with an extension height of 10 nm to 100 nm.

4. The method (300) according to claim 3, characterized in that, Before filling each trench (106), each island structure (101) includes a sacrificial layer (105) extending on a conductive layer (103), and the step of filling each trench (106) with a structural element (107) is carried out until the structural element (107) reaches the top of the sacrificial layer (105) extending on the island structure (101).

5. The method (300) according to claim 4, characterized in that, It also includes selectively etching the sacrificial layer (105) of each island structure (101) relative to the structural element (107) after filling each trench (106) and before forming each protective strip (108), with the etching proceeding up to the conductive layer (103) of the island structure (101).

6. The method (300) according to claim 4 or 5, characterized in that, For each trench (106), filling with structural elements (107) includes the following steps: • Deposit an electrical insulating material layer to completely fill the trench (106); Polish the insulating material layer until the sacrificial layer (105) of each island structure (101) is reached.

7. The method (300) according to claim 4 or 5, characterized in that, For each trench (106), filling with structural elements (107) includes the following steps: • A dielectric layer is conformally deposited in the trench (106); • Deposit a filling material layer on the dielectric layer to completely fill the trench (106); Polish the dielectric and filler layers until the sacrificial layer (105) of each island structure (101) is reached.

8. The method (300) according to claim 7, characterized in that, The filler material is amorphous silicon or polycrystalline silicon.

9. The method (300) according to any one of claims 1 to 8, characterized in that, This includes creeping or expanding the structural element (107) before forming each protective strip (108) so that it covers a portion of the conductive layer of each island structure (101), forming at least one continuous ridgeless free surface extending from the conductive layer (103) of one island structure (101) to the conductive layer of another island structure (101), each free surface having an inclination angle of -45 degrees to 45 degrees relative to the substrate (102), preferably -20 degrees to +20 degrees.

10. The method (300) according to any one of claims 1 to 9, characterized in that, Each protective strip (108) is electrically insulated.

11. The method (300) according to any one of claims 1 to 10, characterized in that, The partially etched structural element (107) includes at least one anisotropic etching stage and at least one isotropic etching stage (e.g., alternating), each anisotropic etching stage being performed in a direction generally perpendicular to the substrate (102).

12. The method (300) according to any one of claims 1 to 11, characterized in that, The process includes anisotropically depositing an additional conductive layer (204) after depositing an organic layer (201), forming two distinct and separate portions (204-1, 204-2) of the additional conductive layer (204), including 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); 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 touch at least one cantilever portion (110a, 110b) of each protective strip.

13. The method (300) according to any one of claims 1 to 12, characterized in that, The partial etching of structural elements (107) is further performed to partially etch the support layer (104) of each island structure (101) such that for each island structure (101), at least a portion (114) of the conductive layer (103) of the island structure (101) hangs outside the support layer (104) of the island structure (101).

14. A light-emitting display device (200) comprising a plurality of island structures (101) disposed on a substrate (102), each island structure comprising a support layer (104) extending on the substrate (102) and a conductive layer (103) extending on the support layer (104), the device further comprising: • At least one groove (106) for separating the island structures (101) in pairs. • At least one protective strip (108), each protective strip connecting the two island structures (101) by crossing a groove (106) separating the two island structures (101), and each protective strip (108) only partially covers each of the two connected island structures (101). • At least one support post (109) at least partially fills the trench (106) and provides electrical insulation to the island structures (101) separated by the trench (106), the height of each support post (109) reaching or exceeding the top of the two island structures (101) separated by the trench, and each support post (109) is positioned below the protective strip (108) to support the protective strip (108) such that at least a portion (110a, 110b) of the protective strip (108) extends and hangs over the support post (109); • An organic layer (201) having two independent and separate portions (201-1, 201-2), including a first portion (201-1) extending continuously on each island structure (101) and each protective strip (108), and a second portion (201-2) extending on the substrate (102) and not contacting the at least one overhanging portion (110a, 110b) of each protective strip (108).

15. The display device (200) according to claim 14, characterized in that, The lateral gap (D110) between the at least one overhanging portion (110a, 110b) of each protective strip (108) and the support post (109) supporting it is strictly greater than 100 nanometers.

16. The display device (200) according to claim 14 or 15, characterized in that, The at least one support (109) is made of an electrically insulating material.

17. The display device (200) according to any one of claims 14 to 16, characterized in that, The at least one pillar (109) includes: a dielectric layer for electrically insulating the island structures (101) separated by the at least one pillar (109), and a filler material for supporting the protective strip (108), wherein the dielectric layer of the at least one pillar separates the filler material of the at least one pillar from each island structure (101).

18. The display device (200) according to any one of claims 14 to 16, characterized in that, The at least one pillar (109) has a continuous, ridgeless surface on which a protective strip (108) extends, and the continuous, ridgeless surface extends from a conductive layer (103) of one island structure (101) to a conductive layer (103) of another island structure (101), and the angle of inclination of the continuous, ridgeless surface relative to the substrate (102) is between -45 degrees and 45 degrees, preferably between -20 degrees and +20 degrees.

19. A light-emitting display system, characterized in that, include: The display device (200) according to any one of claims 14 to 18; And an active addressing matrix comprising multiple transistors, each transistor being connected to a conductive layer (103) of an island structure (101) in the display device (200).

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