CN120827011A

CN120827011A - Method for producing an optoelectronic component and optoelectronic component

Info

Publication number: CN120827011A
Application number: CN202480014130.2A
Authority: CN
Inventors: 安德烈亚斯·汉尼施; 托马斯·哈肯贝克
Original assignee: Ams Osram International GmbH
Current assignee: Ams Osram International GmbH
Priority date: 2023-04-03
Filing date: 2024-03-26
Publication date: 2025-10-21
Also published as: EP4646747A1; KR20250160168A; DE102023108532A1; WO2024208667A1

Abstract

A method for producing an optoelectronic component (l) is described. The method comprises the steps of providing a radiation emitting semiconductor chip (2), providing a layer (3) comprising a partially cured matrix material (4) and comprising a luminescent material (5), joining the radiation emitting semiconductor chip (2) and the layer (3), curing the partially cured matrix material (4) to form a matrix material (6), such that a conversion layer (7) with the matrix material (6) and with the luminescent material (5) is formed in direct contact with the radiation emitting semiconductor chip (2). An optoelectronic component (1), in particular an optoelectronic component with micro-LEDs, is also described.

Description

Method for producing an optoelectronic component and optoelectronic component

A method for manufacturing an optoelectronic device and an optoelectronic device are disclosed.

This patent application claims priority from German patent application 10 202 3 108 532.8, the disclosure of which is incorporated herein by reference.

It is an object of the present invention to provide a simple and efficient method for manufacturing an optoelectronic device. It is a further object of the present invention to provide an optoelectronic device with increased efficiency.

According to at least one embodiment of the method, a radiation emitting semiconductor chip is provided. In particular, the radiation emitting semiconductor chip is configured to emit electromagnetic radiation in the ultraviolet and/or visible wavelength range of the electromagnetic spectrum. For example, radiation-emitting semiconductor chips emit ultraviolet to blue electromagnetic radiation. The radiation-emitting semiconductor chip is, for example, a light-emitting diode chip.

A single semiconductor chip or a plurality of semiconductor chips may be provided in a package (e.g., a wafer package).

According to at least one embodiment of the method, a layer is provided. The layer includes a partially cured matrix material and a phosphor. For example, the layer is provided in the form of a sheet. Alternatively, the layer is the size of the wafer. In particular, the lamellae are similar or identical in shape and/or size to the radiation-emitting semiconductor chips or components of the semiconductor chips when viewed from above.

In particular, the partially cured matrix material is solid at room temperature, i.e., at a temperature in the range of greater than or equal to 20 ℃ to less than or equal to 30 ℃. However, the partially solidified matrix material may be at least partially liquefied or melted by increasing the temperature and/or pressure. In other words, the partially cured matrix material is thermally responsive. The partially cured matrix material exhibits in particular no or only very slight reactivity at room temperature, compared to the cured matrix material formed by crosslinking. Storing the partially cured matrix material at less than 10 ℃ or less than 0 ℃ especially reduces the reactivity of the partially cured matrix material.

In particular, the phosphor is uniformly distributed in the partially cured matrix material. For example, the phosphor is embedded in a partially cured matrix material. The phosphor is capable of converting electromagnetic radiation emitted by the radiation emitting semiconductor chip. For example, phosphors convert electromagnetic radiation emitted by a semiconductor chip into lower energy electromagnetic radiation. It is particularly evident that the phosphor emits electromagnetic radiation at a longer wavelength than the electromagnetic radiation emitted by the radiation emitting semiconductor chip.

The phosphor may also be present in the form of a layer in the partially cured matrix material. Advantageously, this enables better dissipation of any heat converted from the phosphor. Thus, advantageously, temperature sensitive phosphors may also be used.

According to at least one embodiment of the method, the radiation emitting semiconductor chip and the layer are bonded. In particular, the radiation-emitting semiconductor chip and the layer are at least partially, in particular completely, in direct contact with one another during and/or after the bonding. In other words, no further layers, for example additional adhesive layers, are provided between the semiconductor chip and the layer. In particular by using pressure and/or elevated temperature. For example, pressure and elevated temperature are applied to bond the radiation emitting semiconductor chip and the layer. Due to the elevated temperature, the partially cured matrix material may be melted. Due to the pressure, in particular, a sufficient adhesion of the layer to the radiation-emitting semiconductor chip is achieved.

According to at least one embodiment of the method, the partially cured matrix material is cured, in particular fully cured, to form the matrix material. The curing of the partially cured matrix material may be achieved during the bonding of the layer and the radiation emitting semiconductor chip. Curing of the partially cured matrix material is achieved, inter alia, by using temperature and/or pressure. For example, the partially cured matrix material is crosslinked under the influence of an elevated temperature to form the matrix material. Elevated temperature is understood here and below to mean in particular temperatures above room temperature.

According to at least one embodiment of the method, curing is performed to form a conversion layer in direct contact with the radiation emitting semiconductor chip. The conversion layer includes a host material and a phosphor. Thus, the layer comprising the partially cured matrix material and the phosphor is especially a precursor of the conversion layer. In other words, the layer comprising the partially cured matrix material is transformed into a conversion layer upon curing. The matrix material has, for example, adhesive properties. This advantageously ensures an effective adhesion of the conversion layer to the radiation-emitting semiconductor chip, even without an additional adhesive layer.

According to at least one embodiment, a method for manufacturing an optoelectronic device comprises the steps of:

-providing a radiation emitting semiconductor chip,

Providing a layer comprising a partially cured matrix material and phosphor,

Bonding the radiation emitting semiconductor chip and the layer,

-Curing the partially cured matrix material to form a matrix material such that a conversion layer comprising the matrix material and phosphor is formed in direct contact with the radiation emitting semiconductor chip.

Other methods for manufacturing optoelectronic devices use, inter alia, additional adhesive layers in order to bond the radiation emitting semiconductor chip to the conversion layer. In this case, the thickness of the additional adhesive layer is important. If the thickness is too large, this may have a negative effect on the thermal profile in the optoelectronic device. In particular, the thermal profile is understood here and in the following to mean the dissipation of heat generated in the conversion layer on conversion due to stokes shift over the entire radiation-emitting semiconductor chip. Here, the radiation emitting semiconductor chip serves, for example, as a heat sink.

Insufficient heat distribution, particularly insufficient heat dissipation across the radiation emitting semiconductor chip as a heat sink, can reduce the useful life of the optoelectronic device due to overheating of the individual components. Furthermore, the device brightness may be negatively affected by the excessive thickness of the additional adhesive layer or by the formation of a poorly controlled additional adhesive layer. This reduces the emission efficiency of the optoelectronic device. On the other hand, if the additional layer of adhesive is too thin, there is a possibility that damage to the radiation emitting semiconductor chip or formation of bubbles between the radiation emitting semiconductor chip and the conversion layer occurs during bonding of the radiation emitting semiconductor chip and the conversion layer. Bubbles may lead to poor heat distribution, in particular poor heat dissipation and/or low emission efficiency. The low emission efficiency can be explained in particular by the additional scattering centers.

In the case of the invention, the radiation-emitting semiconductor chip is in direct contact with the conversion layer, i.e. no additional adhesive layer is used between the radiation-emitting semiconductor chip and the conversion layer. Thus, an advantageously fabricated optoelectronic device has improved thermal distribution and emission efficiency. Furthermore, the method described herein is advantageous in terms of process control and process stability, because no additional adhesive layer is created between the conversion layer and the radiation emitting semiconductor chip, and thus there are fewer interfaces for potential damage mechanisms related to delamination.

Furthermore, the metering of the adhesive requires an increased effort to achieve, in particular in the case of miniaturized optoelectronic components, for example by using micro LEDs as radiation-emitting semiconductor chips. In the method described herein, this method step is not required, as no additional adhesive layer is present.

Thus, the methods described herein simplify the fabrication of optoelectronic devices while providing more efficient and durable optoelectronic devices. One particular reason is that the radiation-emitting semiconductor chip is in direct contact with the conversion layer, wherein the matrix material is used in particular for adhering the conversion layer to the radiation-emitting semiconductor chip.

According to at least one embodiment of the method, the partially cured matrix material has a lower degree of cross-linking than the matrix material. The degree of crosslinking is herein and hereinafter understood to mean the crosslink density in the material. In other words, the degree of cross-linking of a material describes how many cross-linkable groups in the material have been linked to other cross-linkable groups. In particular, in the present case, the degree of crosslinking does not depend on the number of material groups that can be crosslinked. This means that materials with many crosslinkable groups do not automatically have a higher degree of crosslinking than materials with fewer crosslinkable groups.

According to at least one embodiment of the method, the matrix material comprises a polysiloxane. In particular, the partially cured matrix material is also a polysiloxane, for example a polysiloxane having a lower degree of crosslinking than the matrix material. In other words, the polysiloxane of the partially cured matrix material is a precursor of the polysiloxane of the matrix material.

Polysiloxanes are understood here and below to mean polymers which consist of the structural units M, D, T and/or Q and have a main chain of alternating oxygen atoms and silicon atoms. For example, polysiloxanes have only some carbon-carbon bonds in the backbone, and ideally no carbon-carbon bonds. Polysiloxanes are in particular not block copolymers. This means that the structural units of the polysiloxane are randomly linked to one another in the polysiloxane.

In the M unit (R ₃ SiO-) three organic groups and one oxygen are bonded to one silicon atom. In the D unit (-OSiR ₂ O-) two organic groups and two oxygens are bonded to one silicon atom. In the T unit (-OSiRO ₂ -) an organic group and three oxygens are bonded to a silicon atom. In the Q unit (-OSiO ₃ -) four oxygens are bonded to one silicon atom. The outstanding advantages of polysiloxanes are high thermal and chemical stability.

The organic groups on the silicon atoms are in particular selected independently of one another from the group comprising aliphatic and aromatic hydrocarbon groups. For example, the organic group is methyl (Me, CH ₃), ethyl (CH ₃CH₂, et), propyl (CH ₃CH₂CH₂, pr) or phenyl (Ph, C ₆H₅). The organic groups on the M unit, D unit and T unit may be the same or different.

According to at least one embodiment of the method, the polysiloxane comprises T units in a proportion of at least 25% by weight. In other words, the structural units of the polysiloxane are T units at 25% by weight. In particular, the polysiloxanes have a proportion of T units of at least 50% by weight, in particular at least 70% by weight, for example at least 80% by weight. Polysiloxanes having at least 25% by weight of T units are distinguished by greater hardness and higher thermal stability than polysiloxanes having only D units. Polysiloxanes having only D units are also referred to as silicones.

According to at least one embodiment of the method, the partially cured matrix material has a molecular weight of at least 5000g/mol, in particular at least 10000 g/mol. When the partially cured matrix material is cured, the molecular weight increases, and thus the matrix material has a higher molecular weight than the partially cured matrix material. Due to the high molecular weight, the partially cured matrix material is in particular in the solid state.

According to at least one embodiment of the method, the partially cured matrix material and/or matrix material has a refractive index in the range of greater than or equal to 1.51 to less than or equal to 1.59, in particular greater than or equal to 1.53 to less than or equal to 1.55. Advantageously, the partially cured matrix material and/or the matrix material thus has an increased refractive index compared to other polysiloxanes or silicones.

The additional adhesive layer between the radiation-emitting semiconductor chip and the conversion layer has a refractive index in the range of, for example, greater than or equal to 1.41 to less than or equal to 1.44. The refractive index difference between the radiation emitting semiconductor chip and the additional adhesive layer creating the additional interface may reduce the emission efficiency of the optoelectronic device. Since the methods for manufacturing an optoelectronic device described herein do not use an additional adhesive layer to bond the radiation emitting semiconductor chip and the conversion layer, the emission efficiency of the optoelectronic device is improved. The number of interfaces that are reflected due to the difference in refractive index can be reduced by the absence of an additional adhesive layer.

According to at least one embodiment of the method, the phosphor is a ceramic phosphor and/or a quantum dot phosphor. In particular, the phosphor is a mixture of at least two different phosphors.

According to at least one embodiment, the phosphor comprises at least one material selected from the group consisting of:

Ce ³⁺ doped garnet, such as YAG and LuAG, e.g. (Y, lu, gd, tb) ₃(Al_1-x,Ga_x)₅O₁₂:Ce³⁺;Eu²⁺ doped nitride, such as (Ca,Sr)AlSiN₃:Eu²⁺、Sr(Ca,Sr)Si₂Al₂N₆:Eu²⁺(SCASN)、(Sr,Ca)AlSiN₃·Si₂N₂O:Eu²⁺、(Ca,Ba,Sr)₂Si₅N₈:Eu²⁺、SrLiAl₃N₄:Eu²⁺、SrLi₂Al₂O₂N₂:Eu²⁺;Ce³⁺ doped nitride, e.g. (Ca, sr) Al _(1-4x/3)Si_(1+x)N₃:Ce;(x＝0.2-0.5);Eu²⁺ doped sulfide, (Ba, sr, ca) Si ₂O₂N₂:Eu²⁺, siAlONe, nitrided orthosilicate (e.g. AE _2-x-aRE_xEu_aSi_1-yO_4-x-2yN_x), orthosilicate such as (Ba, sr, ca) ₂SiO₄:Eu²⁺, chlorosilicate such as Ca ₈Mg(SiO₄)₄Cl₂:Eu²⁺;Mn⁴⁺ doped fluoride, e.g. (K, na) ₂(Si,Ti)F₆:Mn⁴⁺;Eu²⁺ or Ce ³⁺ doped silicate, e.g. (Li, na, K, rb, cs) (Li ₃SiO₄): E, wherein e=eu ²⁺,Ce³⁺,(Sr,Li)Li₃AlO₄:Eu²⁺ or SrLi ₃AlO₄:Eu²⁺, and mixtures thereof.

Alternatively or additionally, the phosphor comprises an aluminum-and/or silicon-containing phosphor, in particular selected from the group:

(Ba_1-x-ySr_xCa_y)SiO₄:Eu²⁺(0≤x≤1,0≤y≤1)、(Ba_1-x-ySr_xCa_y)₃SiO₅:Eu²⁺(0≤x≤1,0≤y≤1)、Li₂SrSiO₄:Eu²⁺、 Oxynitride such as the valence ,x≤2)、M_xSi_12-m-nAl_m+nO_nN_16-n:Ce³⁺、AE_2-x-aRE_xEu_aSi_1-yO_4-x-2yN_x(AE＝Sr,Ba,Ca,Mg;RE＝ rare earth element of (Ba_1-x-ySr_xCa_y)Si₂O₂N₂:Eu²⁺(0≤x≤1,0≤y≤1)、SrSiAl₂O₃N₂:Eu²⁺、Ba_4-xCa_xSi₆ON₁₀:Eu²⁺(0≤x≤1)、(Ba_1-xSr_x)Y₂Si₂Al₂O₂N₅:Eu²⁺(0≤x≤1)、Sr_xSi_(6-y)Al_yO_yN_(8-y):Eu²⁺(0.05≤x≤0.5,0.001≤y≤0.5)、Ba₃Si₆O₁₂N₂:Eu²⁺、Si_6-zAl_zO_zN_8-z:Eu²⁺(0≤z≤0.42)、M_xSi_12-m-nAl_m+nO_nN_16-n:Eu²⁺(M＝Li,Mg,Ca,Y;x＝m/v;v＝M), AE _2-x-aRE_xEu_aSi_1-yO_4-x-2yN_x (ae=sr, ba, ca, mg; re=rare earth element), ba ₃Si₆O₁₂N₂:Eu²⁺ or nitride such as La₃Si₆N₁₁N₂:Ce³⁺、(Ba_1-x-ySr_xCa_y)₂Si₅N₈:Eu²⁺、(Ca_1-x-ySr_xBa_y)AlSiN₃:Eu²⁺(0≤x≤1;0≤y≤1)、Sr(Sr_1-xCa_x)Al₂Si₂N₆:Eu²⁺(0≤x≤0.2)、Sr(Sr_1-xCa_x)Al₂Si₂N₆:Ce³⁺(0≤x≤0.2)、SrAlSi₄N₇:Eu²⁺、(Ba_1-x-ySr_xCa_y)SiN₂:Eu²⁺(0≤x≤1;0≤y≤1)、(Ba_1-x-ySr_xCa_y)SiN₂:Ce³⁺(0≤x≤1;0≤y≤1)、(Sr_1-xCa_x)LiAl₃N₄:Eu²⁺(0≤x≤1)、(Ba_1-x-ySr_xCa_y)Mg₂Al₂N₄:Eu²⁺(0≤x≤1;0≤y≤1)、(Ba_1-x-ySr_xCa_y)Mg₃SiN₄:Eu²⁺(0≤x≤1;0≤y≤1), and mixtures thereof.

According to at least one embodiment of the method, the proportion of phosphor in the conversion layer and/or layer is in the range of greater than or equal to 50% by weight to less than or equal to 85% by weight, in particular greater than or equal to 65% by weight to less than or equal to 80% by weight, for example greater than or equal to 70% by weight to less than or equal to 76% by weight. For example, the conversion layer and/or the remainder of the layer is formed of a matrix material or a partially cured matrix material. The proportion of phosphor of at least 50% by weight ensures in particular that the conversion layer is not too soft for dicing. The proportion of phosphor not exceeding 85% by weight advantageously ensures that the conversion layer is hard but not brittle.

According to at least one embodiment of the method, the layer is provided on a carrier. In particular, the carrier comprises a material that is transparent to the phosphor and/or the radiation emitting semiconductor chip. For example, the carrier transmits at least 90%, in particular at least 95%, for example at least 99%, of the electromagnetic radiation emitted by the phosphor and/or the radiation-emitting semiconductor chip. For example, the carrier comprises or consists of glass or sapphire.

Advantageously, the carrier achieves a higher dimensional stability of the layer comprising the partially cured matrix material. This may result in better handling of the layer during the method for manufacturing the optoelectronic device. For example, the carrier also enables a better distribution of forces when bonding the layer and the radiation emitting semiconductor chip.

According to at least one embodiment of the method, providing the layer comprises the steps of providing a carrier, applying a mixture consisting of a partially cured matrix material, phosphor and solvent to the carrier, and removing the solvent such that the layer is formed on the carrier.

In particular, the mixture of the partially cured matrix material, phosphor and solvent is applied to the support by means of a coating method, such as knife coating or casting, or a spray coating process. For example, the solvent is removed by elevated temperature and/or under reduced pressure.

For example, the solvent is selected from carboxylic acid esters or ethers having a boiling point of at least 100 ℃. In particular, the solvents used are methyl ether or acetate. For example, the solvent is Propylene Glycol Monomethyl Ether Acetate (PGMEA), butyl acetate, or anisole.

According to at least one embodiment, the carrier, when provided, has a size that is several times larger than the size of the radiation emitting semiconductor chip, in particular when both are viewed from above. The solvent is removed so that a layer is formed on the support, and then the support including the layer is divided. The singulation is achieved, for example, by stamping, sawing, laser cutting or hybrid cutting. This forms, for example, a sheet, which comprises the layer and is then to be bonded to a radiation emitting semiconductor chip or semiconductor wafer.

The proportion of phosphor in the layer is particularly advantageous in the range of greater than or equal to 50% by weight to less than or equal to 85% by weight when dividing the carrier comprising the layer. Such a proportion of phosphor advantageously ensures that a high quality sawing edge is formed in the singulation.

According to at least one embodiment of the method, the optical properties of the layer are tested before bonding to the radiation emitting semiconductor chip. In particular, the chromaticity of electromagnetic radiation emitted and/or transmitted by this layer is tested. Advantageously, this makes it possible to prevent the production of an optoelectronic device having defective chromaticity. This enables, for example, a reduction in manufacturing costs, since fewer defective optoelectronic devices are manufactured.

According to at least one embodiment of the method, the bonding of the layer and the radiation emitting semiconductor chip is performed at a temperature in the range of greater than or equal to 60 ℃ to less than or equal to 180 ℃, in particular in the range of greater than or equal to 100 ℃ to less than or equal to 150 ℃. In particular, curing the partially cured matrix material to form the matrix material is also performed at this temperature. For example, the partially cured matrix material is polycondensed such that the matrix material is formed. Polycondensation increases, inter alia, the molecular weight.

According to at least one embodiment of the method, curing the partially cured matrix material is performed in a further step. In particular, curing is performed at a temperature in the range of greater than or equal to 60 ℃ to less than or equal to 200 ℃, for example greater than or equal to 100 ℃ to less than or equal to 180 ℃. The curing of the matrix material is carried out in particular for a period of time of greater than or equal to 1 hour to less than or equal to 10 hours, in particular greater than or equal to 1 hour to less than or equal to 5 hours. For example, curing is performed at a temperature of about 160 ℃ for about 4 hours.

According to at least one embodiment of the method, bonding the layer and the radiation emitting semiconductor chip comprises applying a pressure to the layer in the range of greater than or equal to 0.1N to less than or equal to 5N, in particular greater than or equal to 1.0N to less than or equal to 2.5N. Advantageously, a good bonding of the pressure generating layer and the conversion layer to the radiation emitting semiconductor chip is applied to the layer. Furthermore, by appropriately selecting the pressure, the time and/or temperature required for engagement may be reduced. This advantageously enables a greater number of optoelectronic devices to be fabricated per unit time interval.

According to at least one embodiment of the method, bonding the layer and the radiation emitting semiconductor chip comprises applying pressure to the layer for a time length of not more than 60 seconds, in particular not more than 30 seconds, for example not more than 1 second. For example, pressure is applied to the layer for a period of time of about 5 seconds. A time length of not more than 60 seconds enables the layer to be effectively bonded to the radiation emitting semiconductor chip. Temperatures in the range of greater than or equal to 100 ℃ to less than or equal to 150 ℃ and pressures in the range of greater than or equal to 1.0N to less than or equal to 1.5N can advantageously reduce the length of time that pressure is applied to the layer to no more than 5 seconds.

An optoelectronic component is additionally specified. Preferably, the optoelectronic device is manufactured by the method for manufacturing an optoelectronic device described herein. Thus, features, embodiments, and advantages described in connection with the method are also applicable to optoelectronic devices and vice versa. In particular, the statements about the layer comprising the partially cured matrix material also apply to the conversion layer and vice versa.

According to at least one embodiment, an optoelectronic device includes a radiation emitting semiconductor chip. In particular, the radiation-emitting semiconductor chip has a main emission surface.

According to at least one embodiment, an optoelectronic device includes a conversion layer. The conversion layer includes a host material and a phosphor. In particular, the conversion layer is arranged on the main emission surface of the radiation-emitting semiconductor chip.

According to at least one embodiment of the optoelectronic component, the conversion layer is in direct contact with the radiation-emitting semiconductor chip. In particular, the conversion layer is in direct contact with the main emission surface of the radiation-emitting semiconductor chip. In other words, the optoelectronic component does not comprise an additional adhesive layer between the radiation-emitting semiconductor chip and the conversion layer.

According to at least one embodiment of the optoelectronic component, the side of the radiation-emitting semiconductor chip is free of a conversion layer. In particular, the side surfaces extend perpendicularly to the main extension plane of the radiation-emitting semiconductor chip. For example, the side and the primary emission surface form the edges of the optoelectronic device.

According to at least one embodiment, an optoelectronic device comprises a radiation emitting semiconductor chip and a conversion layer comprising a host material and a phosphor, wherein the conversion layer is in direct contact with the radiation emitting semiconductor chip and the side of the radiation emitting semiconductor chip is free of the conversion layer.

The optoelectronic component advantageously exhibits a better thermal distribution due to the direct contact of the conversion layer with the radiation-emitting semiconductor chip. Furthermore, an increase in the reliability of the optoelectronic device can be observed, since no additional adhesive layer is present. Here, the adhesive properties of the matrix material of the conversion layer serve to adhere the conversion layer to the radiation-emitting semiconductor chip.

According to at least one embodiment of the optoelectronic component, the conversion layer and the radiation-emitting semiconductor chip are flush at the sides. In other words, the radiation emitting semiconductor chip and the conversion layer have the same or approximately the same shape and extent when viewed from above. Advantageously, this provides a compact optoelectronic device without protruding areas.

According to at least one embodiment of the optoelectronic component, the carrier is arranged on a side of the conversion layer facing away from the radiation-emitting semiconductor chip. In other words, the conversion layer is arranged between the carrier and the radiation-emitting semiconductor chip. The carrier is in particular in direct contact with the conversion layer. For example, the carrier comprises or consists of glass or sapphire. The carrier is in particular not a lens. For example, the carrier does not include optical structures, such as scattering particles or textured surfaces.

The carrier is advantageously used for mechanically stabilizing the conversion layer, in particular during the method for manufacturing the optoelectronic device.

According to at least one embodiment of the optoelectronic device, the thickness of the carrier is in the range of greater than or equal to 50 microns to less than or equal to 200 microns, in particular greater than or equal to 100 microns to less than or equal to 175 microns.

According to at least one embodiment of the optoelectronic device, the thickness of the conversion layer is in the range of greater than or equal to 10 microns to less than or equal to 250 microns, in particular greater than or equal to 30 microns to less than or equal to 150 microns.

According to at least one embodiment of the optoelectronic device, the conversion layer comprises filler and/or scattering particles. Alternatively, the conversion layer may not include fillers and/or scattering particles. In particular, during the method for manufacturing an optoelectronic device, the layer comprising the partially cured matrix material further comprises filler and/or scattering particles. Advantageously, the filler sets the hardness of the conversion layer. The filler and/or scattering particles may also affect the rheological properties of the layer comprising the partially cured matrix material and/or the conversion layer.

The filler and/or scattering particles are for example non-switching. In other words, the filler and/or scattering particles do not convert electromagnetic radiation radiated by the phosphor in the radiation emitting semiconductor chip and/or the conversion layer.

For example, particles comprising an inorganic oxide such as SiO ₂ are used as filler. The hardness of the conversion layer can be increased using particles comprising an inorganic oxide. Alternatively or additionally, particles comprising polysiloxane may be used as filler. For example, polysiloxanes of filler particles have a higher proportion of D units than the matrix material. This can reduce the hardness of the conversion layer.

The scattering particles comprise in particular inorganic compounds. For example, the scattering particles comprise or are formed of an oxide, such as SiO ₂、TiO₂ or Al ₂O₃, or an oxide, such as SiO ₂、TiO₂ or Al ₂O₃.

According to at least one embodiment of the optoelectronic device, the radiation emitting semiconductor chip comprises a micro light emitting diode (micro LED). In particular, the radiation emitting semiconductor chip is a micro LED.

The micro LEDs may have a width, length, thickness and/or diameter of less than or equal to 100 micrometers, in particular less than or equal to 70 micrometers, for example less than or equal to 50 micrometers. In particular, the edge length of the micro LED (e.g. rectangular micro LED), in particular in a plan view of the layers of the layer stack, has a light emitting area of less than or equal to 70 micrometers, for example less than or equal to 50 micrometers. Micro LEDs are, for example, light emitting diodes in which the growth substrate has been removed, such that the thickness of the micro LED is, for example, in the range of greater than or equal to 1.5 micrometers to less than or equal to 10 micrometers.

For example, micro LEDs are provided on a wafer with a detachable retaining structure. The micro LEDs may be nondestructively separated from the wafer.

According to at least one embodiment of the optoelectronic component, the conversion layer does not separate from the radiation-emitting semiconductor chip under a shear force of at least 0.40 kg·force (kg·f), in particular of at least 0.80kg·f, for example of at least 1.10kg·f. 1 kg.f corresponds in particular to 9.80665N. Thus, the optoelectronic devices described herein are resistant to shear forces similar to optoelectronic devices that include an additional adhesive layer between the radiation emitting semiconductor chip and the conversion layer.

Further described are methods for fabricating an optoelectronic device according to one or more embodiments of the methods described herein, wherein an optoelectronic device according to one or more embodiments of the optoelectronic device described herein is fabricated.

Advantageously, the method is simplified and has fewer steps than other methods. This can be explained, for example, by the fact that no additional adhesive layer is applied. Advantageously, the simplification of the method reduces costs. Optoelectronic components are distinguished in particular by a longer service life and an improved heat distribution.

Other advantageous embodiments, configurations and improvements of the method for manufacturing an optoelectronic device and an optoelectronic device will become apparent from the following exemplary embodiments described in connection with the accompanying drawings.

Fig. 1 to 4 show schematic cross-sectional views of respective steps of a method for manufacturing an optoelectronic device according to an exemplary embodiment.

Fig. 5 shows a graph showing shear forces of various photovoltaic devices.

Identical, similar or identically acting elements are provided with the same reference numerals in the figures. The drawings and the proportions of the elements illustrated in the drawings relative to each other should not be considered to be to scale. Conversely, the individual elements, in particular the layer thicknesses, may be shown in exaggerated dimensions for better illustration and/or better understanding.

In a step for manufacturing the optoelectronic device 1 according to an exemplary embodiment, a radiation emitting semiconductor chip 2 shown in fig. 1 is provided. The radiation emitting semiconductor chip 2 is configured to generate electromagnetic radiation in the ultraviolet to visible range of the electromagnetic spectrum. The generated electromagnetic radiation is emitted through the main emission surface. The main emission surface of the radiation-emitting semiconductor chip 2 is parallel to the main extension plane of the radiation-emitting semiconductor chip 2.

In a further step, shown in fig. 2, a carrier 8 is provided. In the present case, the size of the carrier 8 viewed from above is several times larger than the size of the semiconductor chip 2 viewed from above. The carrier 8 comprises a material transparent to visible light. In the present case, the carrier 8 is made of glass. The thickness of the support 8 is in the range of greater than or equal to 50 microns to less than or equal to 200 microns.

The mixture of the partially cured matrix material 4, solvent and phosphor 5 is applied to the support 8 by knife coating or casting. In the present case, the partially cured matrix material 4 comprises a polysiloxane having T units in a proportion of at least 80% by weight. The partially cured matrix material 4 has a molecular weight of at least 5000 g/mol. The solvent is propylene glycol monomethyl ether acetate. In the present case, the organic groups on the silicon atoms of the siloxane groups in the partially cured matrix material are methyl or phenyl groups.

The solvent is removed at elevated temperature and/or reduced pressure. This forms the carrier 8 shown in fig. 3, which carrier 8 comprises a layer 3, which layer 3 comprises a partially cured matrix material 4 and a phosphor 5. The partially cured matrix material 4 is solid but may liquefy under the influence of elevated temperature and pressure. The layer 3 includes a proportion of the phosphor 5 in a range of greater than or equal to 70% by weight to less than or equal to 72% by weight.

After forming the layer 3, the carrier 8 comprising the layer 3 is singulated by sawing or punching. After it has been divided, the carrier 8 comprising the layer 3 is substantially identical in extent to the semiconductor chip 2 when viewed from above. Thus, a sheet comprising the carrier 8 and the layer 3 is formed by dividing.

A foil is applied to the radiation emitting semiconductor chip 2. In this process, the layer 3 is bonded to the radiation emitting semiconductor chip 2. The layer 3 is in direct contact with the main emission surface of the semiconductor chip 2. The layer 3 is cured while bonding the layer 3 to the radiation emitting semiconductor chip 2. In this process, the partially cured matrix material 4 reacts to form a matrix material 6 and a conversion layer 7 is formed. The matrix material 6 has a higher degree of cross-linking than the partially cured matrix material 4. The partially cured matrix material 4 is cured by pressure and/or elevated temperature induction to form a matrix material 6. The reaction parameters for curing and joining are shown in table 1, which will be described in connection with fig. 5.

The photovoltaic device 1 manufactured by this method is shown in fig. 4. The optoelectronic component 1 comprises a radiation-emitting semiconductor chip 2, a conversion layer 7 and a carrier 8. The conversion layer 7 is in direct contact with the carrier 8 and the radiation emitting semiconductor chip 2. The thickness of the conversion layer is in the range of greater than or equal to 10 microns to less than or equal to 250 microns.

In the present case, the conversion layer 7 comprises a polysiloxane having T units in a proportion of at least 80% by weight as the matrix material 6. The phosphor 5 is distributed in the conversion layer 7. The proportion of the phosphor 5 in the conversion layer is 70% by weight or more and 72% by weight or less. The phosphor is embedded in a matrix material 6.

In the present case, the carrier 8, the conversion layer 7 and the side face 9 of the radiation-emitting semiconductor chip 2 are flush with one another. The conversion layer 7 is arranged on the main emission surface of the radiation-emitting semiconductor chip 2. In the present case, the radiation-emitting semiconductor chip 2 does not comprise its own conversion layer. In other words, the radiation-emitting semiconductor chip 2 emits only electromagnetic radiation generated in the radiation-emitting semiconductor chip 2.

Fig. 5 shows a graph illustrating shear forces F in kg·f experienced by the photovoltaic device 1 produced by the methods described herein. The reference R is used as a reference and represents the shear forces experienced by the optoelectronic device comprising an additional adhesive layer between the cured conversion layer 7 and the radiation emitting semiconductor chip 2. Table 1 reports the method parameters applied in the manufacture of the optoelectronic device 1. In particular, the method parameters are applied in the bonding and curing of the layer 3 and the radiation emitting semiconductor chip 2.

TABLE 1 method parameters

The measured shear force F shows that an increase in temperature and pressure can increase the stability of the optoelectronic device 1 when bonding and curing the radiation emitting semiconductor chip 2 and the layer 3. This is evident by the tolerance of the optoelectronic component 1 to higher shear forces. Furthermore, in some cases, in particular in the exemplary embodiments 5-4, 5-5 and 5-6, the optoelectronic device 1 achieves even higher stability compared to the reference R.

The features and exemplary embodiments described in connection with the figures may be combined with each other according to further exemplary embodiments even if not all combinations are explicitly described. Furthermore, the exemplary embodiments described in connection with the figures may alternatively or additionally include additional features according to the description in the general section.

The description of the invention by means of the exemplary embodiments is not limited thereto. Rather, the invention includes every novel feature and every combination of features, which in particular includes every combination of features in the claims, even if that feature or this combination itself is not explicitly specified in the claims or in the exemplary embodiments.

List of reference marks

1. Optoelectronic component

2. Radiation-emitting semiconductor chip

3. Layer(s)

4. Partially cured dielectric material

5. Phosphor material

6. Matrix material

7. Conversion layer

8. Carrier body

9. Side surface

F shear force

R reference

Claims

1. A method for manufacturing an optoelectronic device (1), comprising the steps of:

Providing a radiation-emitting semiconductor chip (2),

Providing a layer (3) comprising a partially cured matrix material (4) and a phosphor (5),

Bonding the radiation emitting semiconductor chip (2) and the layer (3),

-Curing the partially cured matrix material (4) to form a matrix material (6) such that a conversion layer (7) comprising the matrix material (6) and the phosphor (5) is formed in direct contact with the radiation emitting semiconductor chip (2).

2. Method for manufacturing an optoelectronic device (1) according to the preceding claim, wherein

The partially cured matrix material (4) has a lower degree of cross-linking than the matrix material (6).

3. Method for manufacturing an optoelectronic device (1) according to any one of the preceding claims, wherein the matrix material (6) comprises a polysiloxane.

4. Method for manufacturing an optoelectronic device (1) according to the preceding claim, wherein the polysiloxane comprises T units in a proportion of at least 25% by weight.

5. Method for manufacturing an optoelectronic device (1) according to any of the preceding claims, wherein the partially cured matrix material (4) has a molecular weight of at least 5000 g/mol.

6. The method for manufacturing an optoelectronic device (1) according to any one of the preceding claims, wherein the proportion of the phosphor (5) in the conversion layer (7) is in the range of greater than or equal to 50% by weight to less than or equal to 85% by weight.

7. Method for manufacturing an optoelectronic device (1) according to any of the preceding claims, wherein the layer (3) is provided on a carrier (8).

8. Method for manufacturing an optoelectronic device (1) according to the preceding claim, wherein providing the layer (3) comprises the steps of:

-providing said carrier (8),

-Applying a mixture consisting of the partially cured matrix material (4), the phosphor (5) and a solvent to the carrier (8), and

-Removing the solvent such that the layer (3) is formed on the carrier (8).

9. The method for manufacturing an optoelectronic device (1) according to any of the preceding claims, wherein bonding the layer (3) and the radiation emitting semiconductor chip (2) is performed at a temperature in the range of greater than or equal to 100 ℃ to less than or equal to 150 ℃.

10. The method for manufacturing an optoelectronic device (1) according to any one of the preceding claims, wherein bonding the layer (3) and the radiation emitting semiconductor chip (2) comprises applying a pressure to the layer (3) in the range of greater than or equal to 0.1N to less than or equal to 5N.

11. Method for manufacturing an optoelectronic device (1) according to any of the preceding claims, wherein bonding the layer (3) and the radiation emitting semiconductor chip (2) comprises applying a pressure to the layer (3) for a time length of not more than 60 seconds.

12. An optoelectronic device (1), comprising:

-a radiation emitting semiconductor chip (2), and

-A conversion layer (7) comprising a host material (6) and a phosphor (5), wherein

-The conversion layer (7) is in direct contact with the radiation emitting semiconductor chip (2), and

-The side (9) of the radiation emitting semiconductor chip (2) is free of the conversion layer (7).

13. Optoelectronic device (1) according to the preceding claim, wherein

The conversion layer (7) and the radiation-emitting semiconductor chip (2) are flush at the side face (9).

14. The optoelectronic device (1) according to any one of the preceding claims, wherein

A carrier (8) is arranged on the side of the conversion layer (7) facing away from the radiation-emitting semiconductor chip (2).

15. Optoelectronic device (1) according to the preceding claim, wherein

The thickness of the carrier (8) is in the range of greater than or equal to 50 microns to less than or equal to 200 microns.

16. The optoelectronic device (1) according to any one of the preceding claims, wherein

The thickness of the conversion layer (7) is in the range of greater than or equal to 10 micrometers to less than or equal to 250 micrometers.

17. The optoelectronic device (1) according to any one of the preceding claims, wherein

The conversion layer (7) comprises fillers and/or scattering particles.

18. The optoelectronic device (1) according to any one of the preceding claims, wherein

The radiation emitting semiconductor chip (2) comprises micro LEDs.

19. Method for manufacturing an optoelectronic device (1) according to any one of claims 1 to 11, wherein the optoelectronic device (1) is an optoelectronic device (1) according to any one of claims 12 to 18.