Method for applying a particle material, and optoelectronic semiconductor component comprising a particle material

Abstract

The invention relates to a method for applying a particle material to a target substrate (1), which method comprises a step A) in which the particle material is provided, in the form of multiple individual particles (2), on an auxiliary carrier (3), the particle material being free of a matrix material. In a step B) of the method, at least some of the particles (2) are detached by locally heating the auxiliary carrier (3). In a step C) of the method, detached particles (2) are applied to a main surface (10) of the target substrate (1), the main surface (10) facing the auxiliary carrier (3). The target substrate (1) can be an optoelectronic semiconductor chip (100), in particular a micro-LED.

Description

[0001] 2024PF00918 20 . November 2025

[0002] P2024 , 0715 WO N

[0003] - 1 -

[0004] Description

[0005] METHOD FOR DEPOSITTING A PARTICLE MATERIAL AND OPTOELECTRONIC SEMICONDUCTOR DEVICE COMPLIMENTING WITH A PARTICLE MATERIAL

[0006] A method for depositing a particle material onto a target substrate is described. An optoelectronic semiconductor device comprising a particle material is also described.

[0007] One task to be solved is to specify an improved method for depositing a particle material onto a target substrate. Another task is to specify an improved optoelectronic semiconductor device that can be manufactured using such a method.

[0008] These tasks are solved by the method with the features of independent claim 1 or by an object with the features of claim 17. Advantageous embodiments and further developments are the subject of the respective dependent claims.

[0009] According to at least one embodiment of the method for applying a particle material to a target substrate, in process step A) the particle material is provided on an auxiliary carrier. The particle material is provided as a multitude of individual particles. The particle material is, in particular, free of a matrix material. That is to say, in particular, the particles are 2024PF00918 20 November 2025

[0010] P2024 , 0715 WO N

[0011] - 2 - not embedded in a matrix material and connected to each other via the matrix material .

[0012] The particles exist, for example, as individual particles on the support structure without a direct connection to each other. The particles are, for example, only connected to each other via the support structure.

[0013] The particles can each have a maximum dimension of at most 30 pm, or for example at most 20 pm, or for example at most 10 pm, or for example at most 2 pm. The maximum dimension is the largest external dimension of the particles. If the particles are, for example, spherical or approximately spherical, then the maximum dimension corresponds in particular to the diameter of the particles.

[0014] The particles can be applied directly to the support carrier. Preferably, at least in certain areas, one or more intermediate layers are arranged between the particles and the support carrier, which, for example, increases the adhesion between the particles and the support carrier.

[0015] The particles can be coated alternatively or additionally to increase adhesion between the support carrier and the particles.

[0016] The support structure is, for example, a flexible element such as a film or a film tape. The film or film tape can have adhesive properties so that the particles adhere to the flexible element. Alternatively or additionally, the support structure can include a rigid element such as a glass substrate or a semiconductor substrate. 2024PF00918 November 20, 2025

[0017] P2024 , 0715 WO N

[0018] - 3 -

[0019] According to at least one embodiment of the method for applying a particle material to a target substrate, in a process step B) at least some of the particles are detached by local heating of the support. Step B) is preferably carried out after step A).

[0020] Locally heating the support material can reduce the adhesion between the particle and the support material. For example, the support material can be heated in such a way that the adhesion of only some particles is reduced, allowing these particles to detach. Alternatively, the support material can be heated in such a way that the adhesion of a single particle is reduced, allowing that single particle to detach.

[0021] The heating process can at least partially evaporate an intermediate layer between the support and the particles. The resulting gas evolution can transfer momentum to the corresponding particles, directing them away from the support, thus pushing these particles away from the support and detaching them.

[0022] According to at least one embodiment of the method for applying a particle material to a target substrate, in process step C) detached particles are applied to a major surface of the target substrate facing the support. Step C) is preferably carried out after step B).

[0023] To apply the detached particles to the target substrate, the main surface of the target substrate is brought close, for example in 2024PF00918 20 November 2025

[0024] P2024 , 0715 WO N

[0025] 4. A distance between 50 pm and 200 pm was brought. After detachment, the particles overcome the distance between the support carrier and the target substrate, particularly in free flight.

[0026] An adhesive layer can be arranged on the main surface of the target substrate so that the particles adhere to the target substrate after application.

[0027] The target substrate can comprise a semiconductor body. The target substrate can also be a support for an electrical component or an electrical component itself. In particular, the target substrate can be any element that is to be at least partially coated with the particle material.

[0028] In at least one embodiment, the method for applying a particle material to a target substrate comprises a step A) in which the particle material is provided on an auxiliary carrier as a plurality of individual particles, wherein the particle material is free of a matrix material. In a step B) of the method, at least some of the particles are detached by local heating of the auxiliary carrier. In a step C) of the method, detached particles are applied to a major surface of the target substrate, wherein the major surface faces the auxiliary carrier.

[0029] According to at least one embodiment, the target substrate is an optoelectronic semiconductor chip. The optoelectronic semiconductor chip may include an active region for generating or absorbing electromagnetic radiation. 2024PF00918 20 November 2025

[0030] P2024 , 0715 WO N

[0031] 5

[0032] The active region is located, for example, between a first semiconductor layer and a second semiconductor layer of the semiconductor body. For instance, the first semiconductor layer contains charge carriers of a first type, such as p-type or n-type charge carriers. The second semiconductor layer contains charge carriers of a second type, in particular a type opposite to the first.

[0033] For example, the first semiconductor layer is p-doped and the second semiconductor layer is n-doped. The first and second semiconductor layers can each also comprise two or more sublayers and thus each be designed as a sequence of semiconductor layers.

[0034] For example, the semiconductor body is based on a nitride compound semiconductor material, such as Al n Inj__ n _ m Ga m N, or on a phosphide compound semiconductor material, such as Al n In]__ n-m Ga m P, or on an arsenide compound semiconductor material, such as Al n In]__ n-m Ga m As or Al n In]__ n-m Ga mAsP, where j is 0 < n < 1, 0 < m < 1 and m + n < 1. The semiconductor may contain dopants and additional components. For the sake of simplicity, however, only the essential components of the crystal lattice of the semiconductor, namely Al, As, Ga, In, N and P, are given, even though these may be partially replaced and / or supplemented by small amounts of other substances.

[0035] The active zone is, for example, configured to generate electromagnetic radiation from a wavelength range including the IR range and including the UV range. Preferably, the active zone 2024PF00918 20. November 2025

[0036] P2024 , 0715 WO N

[0037] - 6 - generates radiation in the visible wavelength range during normal operation.

[0038] The active zone includes, in particular, at least one quantum well structure, for example in the form of a quantum dot, a single quantum well (SQW), or a multi-quantum well (MQW), for radiation generation. Additionally, the active zone includes one, preferably several, secondary well structures.

[0039] For example, the main surface of the target substrate is an emission surface of the optoelectronic semiconductor chip. Preferably, a large proportion, for example at least 70%, at least 80%, or at least 90%, of the electromagnetic radiation generated during operation is emitted via this emission surface.

[0040] According to at least one embodiment, the particles include optically active particles. Such optically active particles can, for example, influence radiation generated by the optoelectronic semiconductor chip during operation. For instance, the particles include converter particles and / or scattering particles.

[0041] The converter particles enable the primary radiation emitted by the optoelectronic semiconductor chip to be at least partially converted into secondary radiation with a longer wavelength. The optoelectronic semiconductor chip can thus emit mixed radiation consisting of primary and secondary radiation, with the proportions of primary and secondary radiation in the mixed radiation depending on the converter particles and, for example, their arrangement. The converter particles are 2024PF00918, dated November 20, 2025.

[0042] P2024 , 0715 WO N

[0043] - 7 - for example, phosphorus particles and can be based on a ceramic material. For example, a semiconductor chip emitting in the blue spectral range can emit white light by means of suitable converter particles.

[0044] Scattering particles can particularly influence the radiation characteristics of the optoelectronic semiconductor chip. For example, the optoelectronic semiconductor chip can exhibit a diffuse radiation characteristic due to the scattering particles. The scattering particles can be titanium dioxide particles.

[0045] For example, an optoelectronic semiconductor device can be fabricated by depositing optically active particles onto the optoelectronic semiconductor chip. In particular, if the particle material is a converter material comprising a multitude of converter particles and the target substrate is an optoelectronic semiconductor chip, then the process for depositing a particle material onto a target substrate can also be referred to as a process for fabricating an optoelectronic device.

[0046] Alternatively, the particle material can comprise optically inactive particles. For example, the particle material can be a passivation material. In this case, the particle material can, for example, contain silicon dioxide particles.

[0047] The process described here is based, among other things, on the following technical considerations. For the conversion of electromagnetic radiation, converter materials are applied to an emission surface. 2024PF00918 20 November 2025

[0048] P2024 , 0715 WO N

[0049] - 8 - of the radiation-generating semiconductor chip. The total quantity and distribution of the converter material or converter particles significantly determine the optical properties of the optoelectronic semiconductor chip or the component that comprises the semiconductor chip. Therefore, the application of converter material with the highest possible resolution and accuracy is necessary. Optical properties can include, for example, the chromaticity, brightness, and color-over-angle properties of the semiconductor chip.

[0050] Especially when small optoelectronic semiconductor chips, such as micro-LEDs, are to be coated with a converter material, small quantities of converter particles are necessary, which places special demands on the application process.

[0051] Traditionally, the converter material for application to the semiconductor chip comprises a matrix material in which the converter particles are embedded. The distribution of the converter particles within the matrix material can be uneven, leading to inconsistent or difficult-to-control optical properties of the semiconductor chip or component. For example, the converter particles may form sedimentations, agglomerations, or flow lines within the matrix material. Typically, such converter materials are applied together with the matrix material using dispensing, inking, spray coating, layer attach, doctor blading, or sheet lamination methods. 2024PF00918 November 20, 2025

[0052] P2024 , 0715 WO N

[0053] - 9 -

[0054] The method described here utilizes, among other things, the idea of ​​transferring particles, such as converter particles, onto the target substrate either individually or in groups. This allows even small quantities of particles, such as converter material, to be transferred to the target substrate, such as the optoelectronic semiconductor chip, thus achieving high resolution in the deposition of converter particles. Furthermore, very small quantities of particles can be transferred, which is particularly advantageous for the production of small semiconductor chips, such as micro-LEDs.

[0055] Disadvantages that arise with previously common methods, where the converter material is transferred together with matrix material and where the exact ratio of converter particles to matrix material is unknown, can be overcome simultaneously.

[0056] This advantageously enables the highly repeatable, high-resolution deposition of converter material for the production of optoelectronic semiconductor chips and semiconductor devices with relatively narrow and controllable optical properties. This allows for high production yields and thus low manufacturing costs.

[0057] According to at least one embodiment of the process, the support carrier is locally heated in step B) using laser radiation. In this case, a release layer is preferably arranged between the support carrier and the particles. The release layer can be one of the intermediate layers mentioned above. The release layer is specifically designed to absorb the laser radiation. The release layer can at least partially evaporate during this process. By 2024PF00918 20 November 2025

[0058] P2024 , 0715 WO N

[0059] - 10 - a gas evolution that takes place can transfer momentum to the corresponding particles, which are then detached from the auxiliary carrier .

[0060] Furthermore, the laser radiation can be partially absorbed by the particles that are to be detached, thus further heating the support carrier.

[0061] The particles are preferably, at most, partially embedded in the release layer. The release layer has, for example, a thickness between 100 nm and 2 pm and is relatively thin.

[0062] The particles are preferably irradiated through the auxiliary carrier. In other words, the auxiliary carrier is irradiated from a rear side facing away from the particles. Preferably, the auxiliary carrier is transparent to the laser radiation.

[0063] Laser radiation includes, for example, ultraviolet radiation or radiation in the blue spectral region of the electromagnetic spectrum. It is also possible that laser radiation includes radiation in the red spectral region of the electromagnetic spectrum or infrared radiation.

[0064] Preferably, the laser radiation is focused. The size of the focal spot of the laser radiation determines, in particular, which and how many particles are detached. If the size of the spot is approximately the size of the particles, for example, individual particles can be detached.

[0065] Preferably, the size of the spot can be controlled and adjusted by suitable optics. For example, a di-fractory optical element, or DOE for short, and / or a 2024PF00918 20 November 2025 can be used.

[0066] P2024 , 0715 WO N

[0067] - 11 -

[0068] Beam expanders, also known as beam expanders, are used to adjust the size of the spot.

[0069] In an alternative embodiment, to or in addition to the embodiment mentioned above, the auxiliary carrier can be locally heated by applying an electrical voltage. For example, a resistive layer is integrated into the auxiliary carrier or arranged on the back of the auxiliary carrier. The resistive layer comprises, in particular, a multitude of electrical resistors to which a controlled voltage can be applied, thereby heating the resistors.

[0070] According to at least one embodiment of the method, steps B) and C) are carried out in a field-free environment. This means, in particular, that there is no electric or electromagnetic field, for example, no homogeneous field, between the support carrier and the target substrate. Specifically, the detached particles are not guided along the field lines of an electric or electromagnetic field towards the target substrate.

[0071] If laser radiation is used to detach the particles, a portion of the radiation may be present between the support and the target substrate that is not absorbed by the particles or the detachment layer. However, this portion of the laser radiation is not necessary for particle transfer. In other words, this portion of the laser radiation has no effect on particle movement between the support and the target substrate. 2024PF00918 November 20, 2025

[0072] P2024 , 0715 WO N

[0073] 12

[0074] Preferably, the space between the auxiliary carrier and the target substrate in step C) is filled with air. This means, in particular, that the particles move freely in air during the transfer from the auxiliary carrier to the target substrate.

[0075] Advantageously, the method described here does not place any special demands on the environment. Unlike conventional comparable methods, in which particles in an emulsion are guided along electric field lines, this method can be carried out in a field-free environment and in air. Therefore, the particles and the target substrate advantageously do not need to possess any special properties regarding electrical conductivity and / or moisture resistance.

[0076] According to at least one implementation, the particles are applied homogeneously distributed over the main surface of the target substrate. For example, the areal density of the particles on the main surface is constant or varies by less than 20% or less than 10% along the main surface.

[0077] A homogeneous distribution of the particles on the main surface can, for example, result in a homogeneous luminous pattern if the particles are optically active and the target substrate is an optoelectronic semiconductor chip.

[0078] It is also possible to apply the particles in a controlled, inhomogeneous manner to the main surface. This can be useful in some applications where an inhomogeneous luminescence pattern of an optoelectronic semiconductor chip is desired. 2024PF00918 November 20, 2025

[0079] P2024, 0715 WO N

[0080] - 13 -

[0081] It is advantageous or required for semiconductor components.

[0082] According to at least one embodiment of the process, steps B) and C) are performed repeatedly in succession. In each execution of step B), preferably enough particles are detached such that in the corresponding step C) at most 10% of the main surface area of ​​the target substrate is covered by the particles.

[0083] According to at least one further development of the execution method described above, exactly one particle is detached from the auxiliary carrier during each execution of step B).

[0084] For example, a focal spot or focus area is adjusted to detach the particles from the support individually or in groups.

[0085] For example, the process is used to deposit a converter material onto a main area of ​​an optoelectronic semiconductor chip. The main area, for instance, has dimensions of 80 pm x 40 pm. The converter particles are detached from the substrate using laser radiation. The focal spot of the laser radiation has a size of, for example, 10 pm x 10 pm. This means that with each repetition of steps B) and C), 1 / 32 of the main area is deposited with converter particles. The transfer resolution is therefore 1 / 32. After each repetition of steps B) and C), the homogeneity of the deposited converter particles can be checked and adjusted if necessary. 2024PF00918 20 November 2025

[0086] P2024 , 0715 WO N

[0087] - 14 -

[0088] By repeatedly partially filling the main surface, particle properties such as optical properties of the target substrate, which is for example an optoelectronic semiconductor chip, can be checked between individual or group transfers and the subsequent transfers of the particles can be adjusted.

[0089] According to at least one embodiment, in step B so many particles are detached that in step C essentially the entire main surface of the target substrate is covered by the particles. Advantageously, this allows for a fast and cost-effective application of the particle material to the main surface.

[0090] For example, the procedure is performed to deposit a converter material onto a main area of ​​an optoelectronic semiconductor chip. The main area, for instance, has dimensions of 80 pm x 40 pm. The converter particles are detached from the support carrier using laser radiation. The focal spot of the laser radiation has dimensions of 80 pm x 40 pm. Thus, the entire main area can be deposited with converter particles in a single execution of steps B) and C).

[0091] According to at least one embodiment of the method, the particles are applied to the main surface of the target substrate in a single layer. This means, in particular, that the particles form only one layer on the main surface. The particles are arranged side by side on the main surface and, in particular, are not stacked. 2024PF00918 20 November 2025

[0092] P2024 , 0715 WO N

[0093] - 15 -

[0094] In the following, a mono-layer is understood to mean in particular a single layer in which the particles are arranged next to each other and not on top of each other.

[0095] According to at least one embodiment, the particles are arranged in at least two layers on the main surface of the target substrate. In particular, the layers are stacked on top of each other on the main surface. For example, a single layer of particles is first applied to the main surface. Subsequently, one or more further layers can be applied on top of the single layer.

[0096] For example, the strength of the wavelength conversion can be influenced by arranging the particles in multiple layers if the particles include converter particles and the target substrate is an optoelectronic semiconductor chip. Thus, for instance, the proportion of converted secondary radiation in the mixed radiation can be increased with multiple layers. This allows the color locus of the semiconductor chip or semiconductor device to be adjusted.

[0097] According to at least one embodiment, the particles on the target substrate are at least partially encapsulated with a coating material. The coating material allows the particles to be fixed to their main surface and protected against external influences.

[0098] The encapsulation material can completely surround the particles. The encapsulation material can essentially follow the shape of the particles, especially if it is applied in a relatively thin layer. (2024PF00918, November 20, 2025)

[0099] P2024 , 0715 WO N

[0100] - 16 -

[0101] The thickness of the encapsulation material can, for example, range between 100 nm and 10 pm.

[0102] It is also possible that the encapsulation material only partially surrounds the particles.

[0103] The encapsulation material can be applied after the particles have been deposited, for example, after a final execution of step C). The encapsulation material can be applied using atomic layer deposition (ALD).

[0104] Alternatively, the encapsulation material can be applied before step C). In this case, the particles are at least partially incorporated into the encapsulation material in step C). The encapsulation material can then be liquid or viscous in step C) and cure after the final execution of step C).

[0105] The encapsulation material comprises, for example, a siloxane or a silicone. Preferably, the encapsulation material is transparent to the primary and secondary radiation if the particles are converter particles and the target substrate is an optoelectronic semiconductor chip.

[0106] In the case that several layers of particles are applied, one, some or all layers can be at least partially encapsulated with the encapsulation material.

[0107] According to at least one implementation form, an adhesive layer is arranged on the main surface of the target substrate and 2024PF00918 20 November 2025

[0108] P2024 , 0715 WO N

[0109] - 17 - The particles are applied to the adhesive layer. Preferably, the adhesive layer is applied before step C is carried out. The adhesive layer is designed to fix the particles to the main surface.

[0110] The adhesive layer can have a thickness between 10 nm and 1 pm inclusive. The adhesive layer may consist of, for example, silicone or siloxane.

[0111] Furthermore, the adhesive layer can dampen the impact of the particles on the main surface in step C). This reduces the risk of damage to the target substrate by the particles.

[0112] According to at least one embodiment of the process, the particle material is applied to the support carrier in a single layer. For example, a single layer of particles of the particle material is applied to the support carrier before step A).

[0113] To apply a single layer of particles to the support carrier, an adhesive layer or similar is placed on one of the main surfaces of the support carrier. This main surface can then be pressed into a loose bed of particles, so that a single layer of particles adheres to the main surface. The adhesive layer can also serve as the release layer.

[0114] Alternatively, the monolayer of particles can be produced using electrophoretic disposition (EPD). In this process, an emulsion of the particles is applied to the main surface, and the particles are dispersed via an electric field. 2024PF00918 November 20, 2025

[0115] P2024, 0715 WO N

[0116] - 18 -

[0117] The particles are guided to the main surface. Once the monolayer has formed, the emulsion can be removed.

[0118] Alternatively, the particles can be coated with a hydrophobic coating and immersed in a suitable liquid, such as water. The hydrophobic coating allows the particles to float in a single layer on the water surface, which can then be picked up by the support carrier.

[0119] If the particles are arranged in a single layer on the support, it is advantageous that particles can be easily detached from the support, either individually or in groups.

[0120] According to at least one implementation of the method, the positions of the particles on the support and / or the target substrate are optically detected before step B) and / or after step C). The positions are detected, for example, by means of imaging.

[0121] For example, before step B) is executed for the first time, a map of the particles on the support is created. This map can then be used to precisely detach the particles in subsequent steps. If step B) is executed multiple times, the map can be used for each execution of step B). It is also possible to create a map of the particles on the support before every, every second, every fifth, or every tenth execution of step B). 2024PF00918 November 20, 2025

[0122] P2024 , 0715 WO N

[0123] - 19 -

[0124] Similarly, after each execution of step C), a map of the particles on the target substrate can be created. This advantageously allows for a particularly homogeneous distribution of the particles on the target substrate.

[0125] According to at least one embodiment of the method, in which the particles are optically active particles and the target substrate is an optoelectronic semiconductor chip, an actual value (Iact) of at least one optical property of the semiconductor chip is determined after each execution of step C). Subsequently, the actual value is compared with a target value for the at least one optical property. Steps B) and C) are then repeated until a predetermined maximum deviation between the target value and the actual value is reached.

[0126] Optical properties that can be determined include, for example, a color coordinate, a radiation pattern, a brightness and / or a color-over-angle behavior.

[0127] The specified maximum deviation indicates, for example, a tolerance of the optical property.

[0128] The method described here allows the optically active particles to be transferred individually or in groups, enabling particularly fine-tuning of the optical properties of the semiconductor chip or semiconductor component. This allows the maximum deviation to be advantageously kept relatively small, resulting in tight tolerances. 2024PF00918 November 20, 2025

[0129] P2024 , 0715 WO N

[0130] - 20 -

[0131] According to at least one embodiment of the process, in which the particles are optically active and the target substrate is an optoelectronic semiconductor chip, optical properties, such as conversion rate or scattering characteristics, of the optically active particles are determined on the support carrier after step A). ​​In steps B) and C), only those optically active particles whose optical properties lie within a predefined tolerance range can then be transferred to the semiconductor chip. This allows for an increase in the manufacturing yield of the semiconductor chip or semiconductor device.

[0132] For example, the determination of the optical properties of the particles is carried out in conjunction with the creation of a map of the particle positions. In particular, the map can contain information regarding both the optical properties and the positions of the particles.

[0133] According to at least one embodiment of the process, in which the particles are optically active and the target substrate is an optoelectronic semiconductor chip, the electrical contact structures of the semiconductor chip are covered with a protective layer before step C). The protective layer is, for example, a photoresist. After the final execution of step C), the protective layer can be removed.

[0134] According to at least one embodiment of the method, the particles comprise at least particles of the first kind and at least particles of the second kind, which differ from each other in their optical properties. 2024PF00918 20 November 2025

[0135] P2024 , 0715 WO N

[0136] - 21 -

[0137] For example, both type I and type II particles are converter particles that exhibit different conversion wavelengths or conversion rates. For instance, type I converter particles are configured to convert primary radiation into type I secondary radiation, and type II converter particles are configured to convert primary radiation into type II secondary radiation. Type I and type II secondary radiations differ from each other. A mixed radiation then exhibits, in particular, primary radiation as well as type I and type II secondary radiations. Thus, the bandwidth of the mixed radiation can advantageously be relatively high.

[0138] Alternatively, it is possible that the particles of the first type are converter particles and the particles of the second type are scattering particles.

[0139] It is also possible that the particles of the first type are optically active particles and the particles of the second type are optically inactive particles.

[0140] In further training, it is also possible that the particles include particles of the third type and more.

[0141] According to at least one embodiment of the process, in which particles of the first kind and particles of the second kind are transferred, the particles of the first kind are provided on a first auxiliary carrier and the particles of the second kind are provided on a second auxiliary carrier. Preferably, the particles of the first kind and the particles of the second kind are transferred to the target substrate. In particular, 2024PF00918, November 20, 2025

[0142] P2024 , 0715 WO N

[0143] - 22 - a separate aid carrier is used for each type of particle.

[0144] For example, particles of different types are arranged in separate layers on the target substrate. For instance, particles of the second type can be arranged in a second layer on top of a first layer of particles of the first type on the target substrate. In this case, the particles of the second type can be optically inactive and form a protective layer for the particles of the first type, which can be optically active.

[0145] Alternatively, particles of different types can be arranged in a pattern, for example, alternating. A random distribution of particles of different types on the target substrate is also conceivable.

[0146] Furthermore, an optoelectronic component is specified. This optoelectronic component can be manufactured using a method described here. That is to say, all features of the method described here also apply to the optoelectronic component described here, and vice versa.

[0147] In at least one embodiment, the optoelectronic device comprises a particle material and an optoelectronic semiconductor chip. The particle material is applied as a plurality of individual optically active particles to a main surface of the optoelectronic semiconductor chip. The main surface is, for example, an emission surface of the semiconductor chip. The particle material is preferably free of a matrix material. A [2024PF00918 20. November 2025] is, in particular, located between the particles and the main surface.

[0148] P2024 , 0715 WO N

[0149] - 23 -

[0150] Adhesive layer arranged, wherein the particles are at most partially surrounded by the adhesive layer.

[0151] According to at least one embodiment of the optoelectronic semiconductor device, the maximum particle dimension is at most 30 pm or, for example, at most 10 pm. Preferably, the particles are arranged in a monolayer on the main surface.

[0152] According to at least one embodiment of the optoelectronic semiconductor device, the particles on the main surface are at least partially encapsulated with a coating material. This coating material allows the particles to be fixed to the main surface and protected against external influences.

[0153] The encapsulation material can completely surround the particles. The encapsulation material can essentially follow the shape of the particles, especially if it is applied in a relatively thin layer. For example, the thickness of the encapsulation material can range from 100 nm to 10 pm.

[0154] It is also possible that the encapsulation material only partially surrounds the particles.

[0155] According to at least one embodiment of the optoelectronic semiconductor device, the semiconductor chip and / or the semiconductor component is a micro-LED.

[0156] Broadly defined, a micro-LED could be any light-emitting diode (LED) – generally not a laser – with a particularly small size. 2024PF00918 November 20, 2025

[0157] P2024 , 0715 WO N

[0158] - 24 -

[0159] In the usual case - this is also a very important criterion besides size - a growth substrate is removed in micro-LEDs, so that typical heights of such micro-LEDs are, for example, in the range of 1.5 pm to 10 pm.

[0160] In principle, a micro-LED does not necessarily have to have a rectangular main surface or emission area. For example, an LED with an emission area where, viewed from above, every lateral extent of the emission area is less than or equal to 100 pm or less than or equal to 70 pm could be described as a micro-LED.

[0161] For example, for rectangular micro-LEDs, an edge length of less than or equal to 70 pm or less than or equal to 50 pm is often cited as a criterion, especially when looking at the layers of the layer stack from above.

[0162] Most of these micro-LEDs are provided on wafers with holding structures that can be removed without damaging the pLED.

[0163] Currently, the primary application for micro-LEDs is in displays. Micro-LEDs form pixels or subpixels and emit light of a defined color. Due to their small pixel size and high density with close spacing, micro-LEDs are suitable for small monolithic displays for AR applications, particularly smart glasses. Further applications are also being developed, especially in data communication and pixelated lighting applications. 2024PF00918 November 20, 2025

[0164] P2024 , 0715 WO N

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[0166] In the literature you will find various spellings for micro-LED, e.g. pLED, p-LED, uLED, u-LED or Micro Light Emitting Diode.

[0167] Further advantages and beneficial embodiments and developments of the method and the optoelectronic semiconductor device will become apparent from the exemplary embodiments presented below in conjunction with schematic drawings. Identical, similar, and similarly functioning elements are designated with the same reference symbols in the figures. The figures and the relative sizes of the elements depicted in the figures are not necessarily to be considered as being to scale. Rather, individual elements may be exaggerated for clarity and / or better understanding.

[0168] They show:

[0169] Figure 1 is a block diagram illustrating a method described herein according to a third exemplary embodiment.

[0170] Figure 2 is a schematic view illustrating several process steps of the process according to the first example.

[0171] Figure 3 shows a schematic view of an optoelectronic semiconductor device described herein according to a first embodiment, 2024PF00918, November 20, 2025

[0172] P2024, 0715 WO N

[0173] - 26 -

[0174] Figure 4 shows a schematic view illustrating several process steps of the method according to a second embodiment.

[0175] In the method according to the first embodiment, which is illustrated in Figure 1, an auxiliary carrier 3 is provided in a first step 101. The auxiliary carrier 3 is, for example, a film or a film strip.

[0176] A multitude of individual particles 2 are arranged on the support carrier 3, forming a particle material. The particles 2 are not directly connected to each other, but rather via the support carrier 3 (see Figure 2). The particles 2 are arranged on the support carrier 3 in a monolayer.

[0177] A release layer 5 is arranged between the particles 2 and the support carrier 3. The release layer 5 has adhesive properties, so that the particles 2 adhere to the support carrier 3.

[0178] The particles 2 are specifically converter particles designed for wavelength conversion. These converter particles can partially absorb incident primary radiation and convert it into secondary radiation with a longer wavelength and / or wider bandwidth.

[0179] In a subsequent step 102, the particles 2 on the support carrier 3 are optically detected and measured. In particular, a map of the particles 2 on the support carrier 3 is created. The map can contain information regarding the position of the particles 2 on the support carrier 3 as well as optical properties, such as the conversion rate of the particles 2. 2024PF00918 20 November 2025

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[0181] - 27 - include . The map is stored, for example, in a memory.

[0182] In a further step 103, the particles 2 are detached from the aid carrier 3 and applied to a target substrate 1.

[0183] The target substrate 1 is preferably an optoelectronic semiconductor chip 100. The optoelectronic semiconductor chip 100 is configured to emit primary radiation, for example in the blue spectral range. The optoelectronic semiconductor chip 100 is in particular a pLED. A main surface 10 of the semiconductor chip 100 is in particular an emission surface through which the primary radiation leaves the semiconductor chip 100.

[0184] To detach the particles 2 from the support carrier 3, the support carrier 3 is irradiated with laser radiation 4 (see Figure 2). The laser radiation 4 is incident on a rear side of the support carrier 3 facing away from the particles 2. The support carrier 3 is, in particular, transparent to the laser radiation 4. The laser radiation 4 is preferably UV radiation.

[0185] The laser radiation 4 locally heats the support carrier 3 or the release layer 5 by absorption of the laser radiation 4. In the present embodiment, a focal spot of the laser radiation is selected such that the support carrier 3 is heated only in an area around a single particle 2. Due to the heating, the release layer 5 is locally at least partially vaporized. The associated gas formation transfers a pulse 20 to a particle 2 to be detached, causing it to be launched into free flight, for example in 2024PF00918 20 November 2025

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[0187] - 28 -

[0188] Air to which target substrate 1 is transferred. For example, the distance between the auxiliary carrier 3 and the target substrate 1 is between 50 pm and 200 pm.

[0189] An adhesive layer 7 is applied to the main surface 10. The adhesive layer 7 comprises a silicone or a siloxane. The adhesive layer 7 is designed to fix the particles 2 to the target substrate 1. The adhesive layer 7 surrounds the particles 2 only partially, if at all. The adhesive layer 7 can also dampen the impact of the particles 2 on the main surface 100, thus reducing the risk of damage to the target substrate 1 by the particles 2.

[0190] The target substrate 1, or the optoelectronic semiconductor chip 100, can have contact structures 8. The contact structures 8 can be protected from the particles 2 during step 103 by a protective layer 9 comprising a photoresist.

[0191] In a further step 104, the particles 2 on the target substrate 1 are measured. For example, optical properties and / or positions of the particles 2 on the target substrate 1 are recorded. It is also possible to measure the optical properties of the semiconductor chip 100 after applying some particles 2 to the main surface 10.

[0192] In step 104, an actual value (I) is determined for at least one optical property, such as chromaticity, brightness, or the like. In a subsequent step 105, the actual value is compared with a corresponding target value. If a deviation between the actual value and the target value is greater than a predefined maximum deviation, the 2024PF00918 20 November 2025

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[0194] - 29 -

[0195] Steps 103 to 105 were repeated as illustrated in Figure 1.

[0196] Steps 103 to 105 are repeated until the deviation between the actual value and the target value is less than the specified maximum deviation.

[0197] In step 106, an optoelectronic component 200 is completed.

[0198] Optionally, in step 106, an encapsulation material 6 can be applied to the main surface 10, so that the particles 2 are embedded in the encapsulation material 6 (see Figure 3). The encapsulation material is, for example, silicone. The encapsulation material is applied by atomic layer deposition. The encapsulation material 6 allows the particles 2 to be fixed to the target substrate 1.

[0199] Figure 3 shows an optoelectronic semiconductor device 200, which can be fabricated using the method of Figures 1 and 2. On the main surface 10 of the target substrate 1 or the optoelectronic semiconductor chip 100, the particles 2, which are in particular converter particles, are applied in a mono-layer 11. That is, the particles 2 are arranged side by side on the main surface 10 and are not stacked on top of each other.

[0200] The adhesive layer 7 is arranged between the particles 2 and the main surface 10. The particles 2 are embedded in the encapsulation material 6.

[0201] During operation, 100 primary radiations are generated in the optoelectronic semiconductor chip. The primary radiation has a value of 2024PF00918 on November 20, 2025.

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[0203] - 30 -

[0204] Example wavelengths in the blue spectral region of the electromagnetic spectrum. The primary radiation is emitted via the main surface 10. The primary radiation is at least partially absorbed by the particles 2 and at least partially converted into secondary radiation. The secondary radiation has longer wavelengths and a wider bandwidth than the primary radiation. For example, the secondary radiation has a peak wavelength in the yellow spectral region.

[0205] The semiconductor device 200 emits mixed radiation comprising primary and secondary radiation. The mixed radiation is, for example, white light. Preferably, the adhesive layer 7 and the encapsulation material 6 are transparent to the primary radiation, secondary radiation, and mixed radiation.

[0206] Using the method described here, the particles 2 can be applied to the main surface 10 in groups or individually. Furthermore, the optical properties of the optoelectronic semiconductor device 200 can be monitored during the application of the particles 2 (see step 105 of Figure 1). This allows the optical properties, such as conversion rate, chromaticity, and brightness of the semiconductor device 200, to be precisely adjusted and small tolerance ranges to be achieved.

[0207] In contrast to the method according to Figures 1 and 4, in the method according to the second embodiment, illustrated in Figure 4, several layers 11, 12 are applied to the main surface 10, and the particles 2 comprise particles of the first kind 21 and particles of the second kind 22. 2024PF00918 20 November 2025

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[0209] - 31 -

[0210] In the present exemplary embodiment, the particles of the first kind 21 and the particles of the second kind 22 are converter particles that differ with respect to their conversion properties. The particles of the first kind 21 are configured to convert primary radiation into secondary radiation of the first kind, and the particles of the second kind 22 are configured to convert the primary radiation into secondary radiation of the second kind. The radiation emitted by the finished semiconductor device 200 in this case comprises the primary radiation as well as the secondary radiations of the first and second kind.

[0211] The particles of the first kind 21 are provided on a first auxiliary carrier 31, which has essentially the same features as the auxiliary carrier 3 of the figures.

[0212] I and 4 . The particles of the second kind 22 are applied to a second auxiliary carrier 32, which has essentially the same features as the auxiliary carrier 3 of Figures 1 and 4 .

[0213] From the first and second aid carriers 31, 32, the particles of the first and second kind 21, 22 are transferred to the main surface 10 of the target substrate 1 or of the optoelectronic semiconductor chip 100, in particular using the same methods as in the method according to the first embodiment.

[0214] In the embodiment shown in Figure 4, a first layer 11 is first applied to the main surface 10. The first layer

[0215] II contains exclusively particles of the first kind 21 .

[0216] Subsequently, a second layer 12 is applied to the first layer 11, positioned on one side of the first layer 11 facing away from the target substrate 1. The second layer 12 is 2024PF00918 dated November 20, 2025.

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[0218] - 32 -

[0219] Layer 12 contains particles of the first kind 21 and particles of the second kind 22, which are arranged alternately with each other.

[0220] In contrast to the arrangement of particles of the first kind 21 and particles of the second kind 22 shown in Figure 4, the particles of the first kind and of the second kind 21, 22 can also be arranged differently. For example, it is possible that the second layer 12 contains exclusively particles of the second kind 22, i.e., that the particles of the first kind and of the second kind 21, 22 are separated according to layers 11, 12. A random arrangement of the particles of the first kind and of the second kind 21, 22 is also possible.

[0221] Furthermore, the method according to the second embodiment has the same features, effects and technical advantages as the method according to the first embodiment.

[0222] The invention is not limited to the description provided by the exemplary embodiments. Rather, the invention encompasses every new feature as well as any combination of features, which in particular includes every combination of features in the claims, even if that feature or combination itself is not explicitly stated in the claims or exemplary embodiments.

[0223] This patent application claims priority from German patent application 10 2024 137 364 4, the disclosure content of which is hereby incorporated by reference. 2024PF00918 20 November 2025

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[0225] - 33 -

[0226] Reference character list

[0227] 1 Target substrate

[0228] 2 particles

[0229] 3 aid workers

[0230] 4 Laser radiation

[0231] 5. Delamination layer

[0232] 6 Encapsulation material

[0233] 7 adhesive layer

[0234] 8 Contact structure

[0235] 9 Protective layer

[0236] 10 Main area of ​​the target substrate

[0237] 11 first layer

[0238] 12 second layer

[0239] 21 particles of the first kind

[0240] 22 particles of the second kind

[0241] 31 first aid carrier

[0242] 32 second aid worker

[0243] 100 optoelectronic semiconductor chips

[0244] 101...106 Procedural steps

[0245] 200 optoelectronic semiconductor device

Claims

2024PF00918 November 20, 2025 P2024, 0715 WO N - 34 - Patent claims 1. Method for applying a particle material to a target substrate (1) comprising the following steps: A) Providing the particle material on an auxiliary carrier (3) wherein the particle material is provided as a plurality of individual particles (2) and is free from a matrix material, B) Detachment of at least some of the particles (2) by local heating of the support (3) , C) Applying the detached particles (2) to a main surface (10) of the target substrate (1) which faces the auxiliary carrier (3).

2. Method according to claim 1, wherein the particles (2) comprise converter particles or scattering particles and the target substrate (1) is an optoelectronic semiconductor chip (100).

3. Method according to claim 1 or 2, wherein the auxiliary carrier (3) is locally heated by means of laser radiation (4) and a release layer (5) is arranged between the particles (2) and the auxiliary carrier (3).

4. Method according to any of the preceding claims, wherein at least steps B) and C) are carried out in an environment that is free from an electromagnetic field.

5. Method according to one of the preceding claims, wherein the particles (2) are homogeneously distributed over the main surface (10) of the target substrate (1) are applied. 2024PF00918 November 20, 2025 P2024, 0715 WO N - 35 - 6. Method according to one of the preceding claims, wherein at least steps B) and C) are repeated several times alternately, wherein in each execution of step B) so many particles (2) are detached that in step C) at most 10% of the main surface (10) of the target substrate (1) is covered by the particles (2).

7. Method according to claim 6, wherein in each execution of step B) exactly one particle (2) is detached from the auxiliary carrier (3).

8. Method according to any one of claims 1 to 5, wherein in step B) so many particles (2) are detached that in step C) substantially the entire main surface (10) of the target substrate (1) is covered by the particles (2).

9. Method according to one of the preceding claims, wherein the particles are arranged in a mono-layer (11) on the main surface (10) of the target substrate (1).

10. Method according to any one of claims 1 to 8, wherein the particles (2) are arranged in at least two layers (11, 12) on the main surface (10) of the target substrate (1).

11. Method according to one of the preceding claims, wherein the particles (2) on the target substrate (1) are at least partially encapsulated with an encapsulation material (6).

12. Method according to one of the preceding claims, wherein an adhesive layer (7) is arranged on the main surface (10) of the target substrate (1) and the particles (1) are applied to the adhesive layer (7). 2024PF00918 November 20, 2025 P2024, 0715 WO N 36 13. Method according to one of the preceding claims, wherein to provide the auxiliary carrier (3) the particle material is applied to the auxiliary carrier (3) in a mono-layer.

14. Method according to one of the preceding claims in conjunction with claim 2, wherein after each step C) at least one actual value for optical properties of the semiconductor chip (100) is determined, the actual value is compared with a target value, steps B) and C) are repeated until a predetermined maximum deviation between target value and actual value is reached.

15. Method according to one of the preceding claims in conjunction with claim 2, wherein optical properties of the particles (2) are determined on the auxiliary carrier according to step A), and in steps B) and C) particles (2) are transferred to the semiconductor chip (100) whose optical properties are within a predetermined tolerance range.

16. Method according to one of the preceding claims, wherein the particles (2) comprise at least particles of the first kind (21) and at least particles of the second kind (22) which differ from each other in optical properties, the particles of the first kind (21) being provided on a first auxiliary carrier (31) and the particles of the second kind (22) being provided on a second auxiliary carrier (32), and the particles of the first kind (21) and the particles of the second kind (22) being transferred to the target substrate (1). 2024PF00918 November 20, 2025 P2024, 0715 WO N 37 17. Optoelectronic semiconductor device (200) comprising a particle material and an optoelectronic semiconductor chip (100) , wherein - the particle material is applied as a multitude of individual optically active particles (2) on a main surface (10), - the particle material is free from a matrix material, - an adhesive layer (7) is arranged between the particles (2) and the main surface (10), and - the particles (2) are at most partially surrounded by the adhesive layer (10).

18. Optoelectronic semiconductor device (200) according to claim 17, wherein a maximum dimension of the particles (2) is at most 30 pm, and the particles (2) are arranged in a mono-layer (11) on the main surface (10).

19. Optoelectronic semiconductor device (200) according to claim 17 or 18, wherein the particles (2) on the main surface (10) are at least partially encapsulated with an encapsulation material (6).

20. Optoelectronic semiconductor device (200) according to one of claims 17 to 19, wherein the semiconductor chip (100) is a micro-LED.

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