Method for producing a multilayer receiver material for use in the processing of MicroLEDs and a starting film element for providing it and a multilayer receiver material and its use in such a method

Abstract

The invention relates to a method for producing a receiver material (10), comprising the method steps: a) producing or providing a flat film element (12) having a first film surface (14) and a second film surface (16), wherein the flat film element (12) consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the flat film element (12) has an adhesive force on the first film surface (14) in the range of 0.5 cN / cm to 120 cN / cm, measured according to test method J0PMA002 based on DIN EN 1939:2003, b) producing or providing a base substrate (18) having a base substrate surface (20), c) contacting the second film surface (16) with a plasma to obtain a plasma-activated second film surface (16),d) contacting the base substrate surface (20) with a plasma to obtain a plasma-activated base substrate surface (20), e) applying the film element (12) with the plasma-activated second film surface (16) to the plasma-activated base substrate surface (20) of the base substrate (18) to obtain the receiver material (10), wherein the surface of the receiver material (10) is partially formed by the first film surface (14).

Description

The invention relates to a method for producing a multilayer receiver material, in particular for use in the processing of MicroLED, to a corresponding receiver material and to a starting film element for use in a corresponding method, and to the use of a corresponding receiver material in the processing of MicroLED. A method for processing MicroLED with a corresponding receiver material is also disclosed.The use of MicroLED technology in the production of electronic products, in particular of their displays, is one of the future technologies in this field. The term MicroLED, as a generic term in common usage, denotes a flat panel technology in which a picture element or a pixel is formed from arrays of microscopically small inorganic LEDs. These inorganic LEDs, which typically have dimensions of about 5 to 100 μm, are themselves likewise referred to as MicroLEDs. Such microLEDs can be produced, for example, in the colors red, green and blue and can be produced, for example, by epitaxial growth on corresponding epi-wafers, in particular sapphire wafers, wherein a single wafer can comprise several million individual microLEDs.In the implementation of MicroLED technology, with a view to the complex and demanding handling of such MicroLEDs, there is the great need to enable a largely automated series production of corresponding products and in the process to enable a high process reliability and constant product quality. Time and cost effective processing of micron sized LEDs is therefore important for the development of future product lines for various industries, such as the electrical industry.In this case, the challenge arises in the practical implementation of this technology to transfer the microLEDs grown on suitable substrates, for example sapphire wafers, reliably and controllably from these substrates to a target substrate, and in the process to arrange them in particular precisely in a desired arrangement. A direct transfer from the sapphire wafer to the target substrate, which can be a display, for example, has in many cases proved to be technically implementable, for example by manual transfer of the individual microLED being effected by mechanical picking up and transfer by means of a vacuum robot, but is usually perceived as disadvantageous. In particular, it is considered disadvantageous here that such a transmission on an industrial scale is usually not able to be carried out in a time- and cost-effective manner, wherein, moreover, there is a high risk of damage to the microLEDs during manual transmission by means of the vacuum robot. In addition, the mechanical methods used usually also have limitations in the dimension of the handled MicroLED.In the prior art, to overcome this problem, a temporary transfer of the MicroLED to a suitable receiver material is proposed, for example by means of a so-called laser-induced forward transfer method (LIFT), in which the MicroLEDs are detached from the sapphire wafer and transferred to a receiver material. The microLEDs can be transferred again from the receiver material by means of LIFT methods and thereby applied to the target substrate, in particular a display.The corresponding LIFT method is known to the person skilled in the art. In this respect, reference is made in particular to the products and publications of the company Coherent Laser Systems, for example the article "Laser in the display production: microLED lift-off, transfer, and repair" which can be called on-line, on October 4, 2022. Further explanations regarding the LIFT method can also be found in particular in the publication U. Eppelt et al., "Numerical Simulation for GaN-based MicroLED Laser Induced Forward Transfer (LIFT) and Comparison With Real-Time Measurements of the Flight Phase"; SID Symposium Digest of Technical Papers 54(1):954-957, August 2023 (DOI:10.1002 / sdtp.16725). Further explanations regarding the LIFT method in the context of the present invention can also be found in the following description of the figures.In the LIFT process, the MicroLEDs are catapulted-referred to in simplified terms-by a laser-induced evolution of gas as a result of thermal loading of subject material onto the receiver material, from which they are subsequently to be transferred to the target substrate, for example by means of a new LIFT process. The laser-induced gas development can take place, for example, by the irradiation of GaN or InGaN, which, as a result of the energy input at the high pulse power density of the lasers used, supplies a fluid-driven drive for the MicroLED, wherein in principle different mechanisms can contribute, for example sublimation of the material into a gaseous or plasma state or the release of nitrogen gas.In order to be able to ensure this process procedure in a controlled manner and without damaging the MicroLED, high requirements are placed on the receiver material. In particular, it is necessary for the MicroLED transferred to the receiver material by means of LIFT to be able to strike the latter sufficiently gently in order to avoid damage as much as possible. In addition, the receiver material must have sufficient adhesion to the receiving side provided for the impinging microLEDs in order to enable secure retention of the microLEDs on the receiver material, even in the event of minor vibrations, and to avoid undesired dropping. At the same time, however, the material must also permit reliable renewed detachment of the MicroLED from the receiver material and must not be too tacky for this purpose. Thus, in the development and design of a suitable receiver material, there is a conflict of goals between sufficient adhesion for the incorporation of the microLED on the one hand and simple and reliable transfer to the final target substrate on the other hand. Since the detachment of the MicroLED from the receiver material should ideally also be possible in turn by means of LIFT, stringent requirements are also placed on the receiver material with regard to the optical properties. In addition, there is great interest in providing a solution for the production of suitable receiver materials which can be produced with low outlay and low production costs, in particular also in large numbers.Solutions for receiver materials are known from the prior art in which quartz wafers, to which a surface coating has been applied by means of liquid coatings-optionally using an adhesion promoter-are intended to meet the requirements described above as receiver material. However, the high expenditure on time and energy, which has to be expended for the production of corresponding wafers due to the complicated processing, in particular the cleaning and the spin coating process in the clean room, is often perceived as disadvantageous in this case. In addition, the costs arising, for example, from the operation of the clean room, and qualitative defects, such as, for example, coating supernatants at the wafer edges, are perceived as disadvantageous in this case. In addition, many spin coating systems are relatively inflexible with regard to adapting to different substrates and coatings and can often coat almost only in one size or quality / dimension. A desirable flexibility in the coating usually requires large investments in the plant park and a high level of personnel outlay.In this respect, it has not been possible to find yet, after the inventors have been studied, an entirely advantageous production process for receiver materials which can fully satisfy the requirements of the industry with regard to advantageous handling of microLEDs with simultaneous time and cost efficiency of the production process.DE 10 2021 206 403 A1 relates to a method and a system for producing a microstructured component which has a multiplicity of multifunctional elements on a substrate, wherein laser processing is carried out in at least one process stage in a laser processing station under the control of a control unit. A preferred field of application is the production of a micro-LED display, which has a substrate which carries micro-LEDs forming an array of pixels, which micro-LEDs are arranged on an electrical supply structure arranged on the substrate.WO 2023 / 157 709 A1 discusses a laser-induced forward transfer method (LIFT method) in the processing of MicroLEDs.DE 10 2014 222 723 A1 relates to a method for the indirect plasma treatment of a release layer, comprising the steps of: introducing a plasma gas into a discharge space; exciting the plasma gas into a plasma state by discharge; blowing out the plasma gas in a plasma state from the discharge space; and exposing the release layer to the plasma gas in a plasma state after blowing out the plasma gas from the discharge space.WO 2024 / 085 024 A1 deals with transfer methods such as LIFT and laser lift-off (LLO) for MicroLEDs and shows a receiver / donor material having a base substrate and a resin layer which may be flexible.The primary object of the present invention was to eliminate or at least reduce the disadvantages of the prior art.In particular, it was the object of the present invention to specify a method for producing a receiver material, with which receiver materials can be obtained which can reliably solve the conflict of goals between a surface condition optimized for the inclusion of a large number of MicroLEDs, in particular a sufficient adhesion, and a condition favorable for further processing, in particular by means of laser-assisted methods. In addition to adhesion, advantageous wetting is also desired, i.e., the ability of the receiver material to wet a solid surface, which is desirable to ensure that the two materials can well contact each other. In this respect, it was a particular object of the present invention that the surface condition of the receiver materials to be produced should be able to be optimized reliably and reproducibly for the recording of MicroLED, wherein defects on the recording surface in particular should be able to be reliably avoided.It was an object of the present invention that the receiver materials produced in the method to be specified should have favorable properties for the process control in the LIFT method, in particular a high temperature stability and a sufficient transparency to laser radiation, in particular EUV and DUV lasers, wherein the receiver material to be specified should in particular be as free as possible from contaminants and polymer defects on the μm or nm level, bubbles, lenses and / or anisotropy, wherein in particular defects whose dimensions are of the order of magnitude of the size of the MicroLED can prevent reliable reception on the receiver material.It was likewise an object of the present invention that the method to be specified should enable more cost-efficient and time-efficient production of receiver materials than the prior art, wherein in particular the dependence on liquid-based coating methods should be able to be reduced. In this respect, it was an important aspect of the present invention that the production method to be specified should be able to avoid the occurrence of defects in the receiver material, in particular defects at boundary surfaces in the receiver material.In addition, it was an object of the present invention to specify a starting film element for providing a semifinished product required for the method to be specified.Moreover, it was an object of the present invention to provide a corresponding receiver material which can be produced or is produced using the method to be specified.It was furthermore an object of the present invention to specify a use of corresponding receiver materials in the processing of MicroLED, in particular in the production of displays.In this respect, it was a secondary object of the present invention to provide a method for processing MicroLED with the receiver material to be specified.The inventors of the present invention have now found that the objects described above can be achieved if, in a method for producing a receiver material, instead of using wet chemical coating methods, a planar film element made of a particular film material having a relatively low surface tackiness is applied to a base substrate, the surfaces of the film element and of the base substrate contacting them thereby being plasma-activated in each case before application, as defined in the claims. As a result, receiver materials are advantageously obtained in an extremely time- and cost-effective manner, which receiver materials have the required properties for sufficient adhesion of MicroLED to the surface of the film element facing away from the base substrate and, moreover, have a sufficiently low absorption for the relevant laser radiation. The adhesion property of the adhesive film is selected to be so low that a later renewed transfer of the MicroLED remains possible. The two-sided plasma activation provided by the inventors of both the sheet-like film element and the receiving base substrate advantageously enables the sufficiently firm and stable connection of these elements in order to avoid slipping and undesirable formation of waves or other defects in the applied film element despite the inherently low adhesive force of the film element. The use of a corresponding film element can advantageously be adapted much more flexibly to the desired dimensions of the substrate and the other requirements of the respective application, for example by die-cut trimming, as a liquid coating method.The above objects are thus achieved by the subject matter of the invention as defined in the claims. Preferred embodiments according to the invention are evident from the dependent claims and the following explanations.Such embodiments, which are referred to below as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are thus very particularly preferred. Also preferred are embodiments in which a feature of one embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred receiver materials, starting sheet elements and processing methods result from the features of preferred methods for producing the receiver material.The invention relates in particular to a method for producing a multilayer receiver material, in particular for use in the processing of MicroLED, comprising the method steps: a) producing or providing a sheet-like film element, having a first film surface and a second film surface, wherein the sheet-like film element consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element has an adhesive force on the first film surface in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002, as described below, on the basis of DIN EN 1939:2003, b) producing or providing a base substrate, having a base substrate surface, c) activating the second film surface with a plasma to obtain a plasma-activated second film surface, d) activating the base substrate surface with a plasma to obtain a plasma-activated base substrate surface, e) applying the film element with the plasma-activated second film surface to the plasma-activated base substrate surface of the base substrate to obtain the multilayer receiver material, wherein the surface of the multilayer receiver material is formed partially by the first film surface.The method of the present invention is for the preparation of a specific receiver material. The term "receiver material" takes into account the fact that corresponding receiver materials are provided and intended to function as receivers for the microLED taken over by the EPI wafer when used in the processing of microLED, in particular in the LIFT method. Since it is provided that the MicroLED thus transferred are subsequently to be transferred to a target substrate, in particular again by means of LIFT methods, the receiver materials could for some time also be referred to as "receiver / donor material", of which, however, within the scope of the present invention, one would omit with a view to an efficient description of the invention.In method step a), a planar film element is first provided, which is intended to form the surface provided for receiving the microLED in the subsequent multilayer receiver material, the surface properties of which surface element are optimized for receiving microLED in the LIFT method.The term "planar" expresses here that the film element has a significantly greater extent in the surface than in the spatial direction perpendicular to this surface.The use of a sheet-like film element, which can be provided as a prepared semi-finished product as disclosed below, is a significant difference in this case compared to postchemical coating processes.Corresponding planar film elements can be designed optimally with regard to their dimensions in the surface on the base substrates to be coated therewith, so that in particular an undesired protrusion of the film element on the edges of the base substrate can be avoided, whereby it can be prevented that a mechanical load on the surface receiving the microLED promotes defects in the edge region. By way of example, in this respect, a method according to the invention is exemplary for typical wafer base substrates, wherein the first film surface has a surface area of 10 cm 2 or more, alternatively of 50 cm 2 or more, further alternatively of 100 cm 2 or more, again alternatively of 200 cm 2 or more, in particular alternatively of 600 cm 2 or more. In addition to classic round shapes, wafer base substrates can also have other basic shapes and can be embodied, for example, as rectangular or square.For use in the method, relatively thin films are particularly preferred, with which the base substrate can be efficiently provided with a thin surface coating. These thin film elements have numerous advantages. In addition to a reduced material requirement, the low intrinsic weight is advantageous for good bond adhesion to the base substrate. In addition, the length of the beam path that a laser radiating through the receiver material must travel through the film element is reduced, wherein any effects of residual absorption in the film element can be minimized. A method according to the invention is accordingly preferred, wherein the planar film element has an average thickness in the range from 2 to 5000 μm, preferably in the range from 4 to 1000 μm, particularly preferably in the range from 6 to 500 μm, very particularly preferably in the range from 8 to 200 μm, in particular preferably in the range from 10 to 100 μm.Decisive for the advantageous suitability of the multilayer receiver materials produced is the specific selection of material in the film element, the material of which is referred to as "film material".The skilled person understands that it would in principle be conceivable to design the film element partly from other materials, for example in areas which are not provided for the accommodation of MicroLED. Accordingly, it is conceivable, at least in theory, for the film element also to comprise material, which is not the corresponding film material, for example in the edge regions. However, those skilled in the art will appreciate that the advantages of the present invention result from the use of a specific sheet material. Since it is also usually very complicated to form such thin film materials in sections from different plastic materials, it is preferred for substantially all embodiments that planar film element and thus also its surface are formed as largely as possible from the specific film material. A method according to the invention is accordingly preferred, wherein the planar film element consists of the film material to a mass fraction of 80% or more, preferably 90% or more, particularly preferably 95% or more, very particularly preferably 99% or more, in particular preferably 100%.Preference is also given, additionally or alternatively, to a process according to the invention, where the first film surface is formed by the film material to an extent of 80% or more, preferably 90% or more, particularly preferably 95% or more, very particularly preferably 99% or more, particularly preferably 100%, based on the surface of the first film surface, and / or where the second film surface is formed by the film material to an extent of 80% or more, preferably 90% or more, particularly preferably 95% or more, very particularly preferably 99% or more, particularly preferably 100%, based on the surface of the second film surface.According to the invention, the film material is a material from the class of substances of silicone rubbers which is combined at least with a filler. Accordingly, the film material comprises one or more silicone rubbers and one or more fillers.These constituents are each employed as "one or more" in accordance with the skilled artisan. The term "one or more" refers in the usual manner in industry to the chemical nature of the corresponding compounds and not to their amount of substance. For example, the curable adhesive may comprise as filler exclusively a pyrogenic amorphous silicon dioxide, which would mean that the curable adhesive comprises a large number of the corresponding filler particles.Insofar as mass fractions of constituents of the film material are given below, these are usually given in industry as combined mass fractions of the one or more components, which means that the mass fraction of the correspondingly formed components, taken together, meets the corresponding criteria, the mass of the film material being the reference system in each case in the absence of other indications.Silicone rubbers are well known to the person skilled in the art of plastics processing, in particular to the person skilled in the art of bonding technology, and are commercially available from numerous different suppliers. Silicone rubbers and compositions based thereon are disclosed, for example, in the technical book by I. Benedek et al., "Technology of Pressure-Sensitive Adhesives and Products", 2009, ISBN 9781420059397. Silicone rubbers are based on poly(organo)siloxanes, which can usually be crosslinked via polymerizable groups. An exemplary poly(organo)siloxane is, for example, polydimethylsiloxane (PDMS) which can be used as a base for the silicone rubber. Crosslinkers used for the poly(organo)siloxanes for forming the silicone rubber can be conventional crosslinkers known to the skilled worker, for example addition-crosslinking crosslinkers, such as, for example, an organic peroxide such as 2,4-dichlorobenzoyl peroxide. The crosslinking reaction is mostly catalyzed by a catalyst. A frequently used catalyst system for addition-crosslinking silicone rubbers consists of platinum compounds. To improve the bonding of the silicon-containing fillers used to the rubber base, silane coupling agents, such as gamma-methacryloxypropyltrimethoxysilane, for example, can also be used.With regard to the proportions of the rubbers, preference is given to a process according to the invention, wherein the film material comprises the one or more silicone rubbers in a combined proportion by mass in the range from 30 to 90%, preferably in the range from 40 to 85%, particularly preferably in the range from 50 to 80%, preferably in the range from 50 to 70%, based on the mass of the film material.According to the inventors' judgment, it is necessary with regard to the intended processing properties of the sheet-like film element, in particular its mechanical properties, for the film material to contain fillers. In the experiments of the inventors, it has been found that particularly advantageous film elements can be obtained, in particular with regard to the required transparency to laser radiation of the relevant wavelength ranges, in particular by using amorphous silicon dioxide. Particularly advantageous results were achieved here, in particular with pyrogenic and precipitated amorphous silicon dioxide, wherein the pyrogenic species in turn resulted in particularly powerful materials. Pyrogenic and precipitated amorphous silicon dioxide are sometimes also referred to as pyrogenic silicic acid or precipitated silicic acid (historically conditioned and not technically applicable). Against this background, a method according to the invention is preferred, wherein the one or more fillers are selected from the group consisting of inorganic fillers, preferably selected from the group consisting of amorphous silicon dioxide, particularly preferably selected from the group consisting of precipitated silicon dioxide and pyrogenic silicon dioxide, in particular pyrogenic silicon dioxide.With regard to the contents of fillers, a method according to the invention is preferred, wherein the film material comprises the one or more fillers in a combined mass proportion in the range from 10 to 70%, preferably in the range from 15 to 60%, particularly preferably in the range from 20 to 50%, preferably in the range from 30 to 50%, based on the mass of the film material.In addition to silicone rubber and fillers, it is also possible, at least in principle, to use further additives customary in the field of adhesive technology in order to optimize the application properties of the film material. This use is effected with the proviso that these additives do not adversely affect the setting of the adhesion forces defined above and also do not adversely affect the desired transparency to the desired laser radiation. Overall, however, it is preferred, according to the inventors' judgment, to keep the proportion of additives rather low. A method according to the invention is thus conceivable, wherein the film material additionally comprises:iii) comprises one or more additives, preferably in a combined proportion by mass of less than 15%, preferably less than 10%, particularly preferably less than 5%, based on the mass of the film material.The inventors have identified it to be particularly advantageous if the glass transition temperature of the film material, which can be determined in the customary manner by means of DSC, is set relatively low. A preferred method is namely one in which the film material has a glass transition temperature Tg, measured by means of DSC, in the range from -155 to -80° C., preferably in the range from -140 to -100° C.In order to solve the conflict of goals outlined above between a certain adhesion of the received MicroPTFE and the possibility of later easy detachment, it is essential that the bond strength of the film surface is adjusted in a targeted manner, wherein the above-defined ranges are significantly lower than would be typical for conventional silicone rubber adhesives, so that the first film material can be regarded from the point of view of the skilled worker as a viscoelastic extensible material rather than as an adhesive.The measurement of the bond strength is carried out according to the test method designated J0PM002. The J0PM002 is based on DIN EN 1939:2003 and is similar thereto, wherein the J0PM002 is also similar to other comparable standards for bond strength determination, such as ASTM330 or EN ISO 29862:2019. Accordingly, if the values are not in the limit range of the defined ranges, recourse can also be had, as an aid, to the corresponding methods from DIN EN 1939:2003, ASTM330 or EN ISO 29862:2019. However, J0PM002is particularly suitable for the present measurements. The force required to peel off an adhesive tape strip at a defined speed at an angle of 180° from a standardized test substrate is determined. The determination is carried out at 23° C. (±1° C.) and 50% (± 5%) relative humidity at a draw-off speed of 300 mm / min and a draw-off angle of 180° using a tensile testing device (Zwick company). As the reinforcing film, an aluminum vapor-deposited PET film having a thickness of 25 μm was used on the side facing the film material. Steel plates (50 x 200 mm; 2 to 3 mm thickness; ground with sandpaper 240, roughness depth about 100 nm) are used as substrate. The test strip is bonded by means of a rolling machine at 4 kg in 5 rolling processes at 5 m / min at a temperature of 23° C. The adhesive tapes are removed immediately after application.With regard to the bond strength, a method according to the invention is preferred for advantageously solving the conflict of goals, wherein the flat film element has a bond strength on the first film surface in the range from 0.5 cN / cm to 100 cN / cm, preferably in the range from 0.7 cN / cm to 80 cN / cm, particularly preferably in the range from 1 cN / cm to 70 cN / cm, very particularly preferably in the range from 2 cN / cm to 60 cN / cm, particularly preferably in the range from 5 cN / cm to 50 cN / cm.In the light of the above explanations concerning the material-technology configuration of the film element, it is clear to the person skilled in the art that the two surfaces of the thin sheet-like film element will in practice be identical at least with regard to the material in most cases. Even if the measured bond strength on the two surfaces can differ slightly by secondary effects, for example the surface roughness, the two surfaces will, however, have a very similar bond strength in the very vast majority of cases. A method according to the invention is thus relevant for the widely predominant number of applications, wherein the planar film element has an adhesive force on the second film surface in the same range as on the first film surface.The low adhesive force of the film element, which is so advantageous for handling the micro-LED, disadvantageously leads to the fact that the fixing of the flat film element on the base substrate is not possible due to the inherent adhesive force of the film element. This low adhesion to the base substrate resulted in the first experiments of the inventors that the film element was difficult to apply and also tended to peel off and form irregularities after application.Many of the measures known from the field of technology for increasing the adhesion between the base substrate and the film element were not only associated with disadvantageously high expenditure in many cases, but, if they were able to allow favourable adhesion at all, also resulted in a disadvantageous reduction in the laser transparency, by means of which the suitability for the LIFT method could not be ensured, so that, for example, the use of adhesion promoters was identified as unsuitable. In this case, it was also found in particular that only one-sided plasma activation of the film element was not suitable for achieving the desired performance profile. The one-sided plasma activation, either on one side of the base substrate surface or on one side of the second film surface, did not lead to a suitable increased improvement in the adhesion in the experiments of the inventors, so that the flat film element was very easily peeled off.The inventors have found in the course of development that, starting from the experiments of the inventors, only a plasma activation on both sides, i.e. a plasma activation in which both the film element and the surface of the base substrate provided for the application are treated by means of a plasma, enables the desired combination of an advantageous adhesion of the specific film material to the base substrate while simultaneously ensuring a high laser transparency.The concept of a plasma and the principle of using plasma for activation are well known to those skilled in the art. The term plasma refers to an at least partially ionized particle mixture which may contain various reactive species, particularly ions, radicals and free electrons. The surface treatment is usually carried out by contacting the surface to be treated or at least by establishing a direct spatial proximity, wherein the reactive species of the plasma can react with the material present on the surface in order to generate at least temporarily reactive centers on the surface and, for example, to change the wettability of the surface.Based on the general knowledge of the art, various types of plasmas and their uses for surface activation are known to the skilled person. Suitable devices with which corresponding plasmas can be generated and which can also be used in the context of the present invention are commercially available from numerous suppliers.In principle, a wide number of plasmas can be used in the context of the present invention. Theoretically, the use of low-pressure or vacuum plasmas is also conceivable. However, low-pressure or vacuum plasmas of this type are considered less preferred in view of the required outlay on apparatus and the process efficiency. A method according to the invention is preferred, wherein the plasma is an atmospheric pressure plasma.The process gases used are the customary process gases, for example. nitrogen or inert gases such as argon or helium, or process gas mixtures, for example. Air or forming gas may be used. While the use of pure oxygen plasmas is less preferred as estimated by the inventors, the use of air as process gas is preferred both in terms of cost efficiency and in terms of the effect achieved.According to the inventors' judgment, in particular, plasmas formed by electric discharge are particularly preferred. Such methods for using a plasma are known, for example, as piezoelectric direct discharge plasma or as corona treatment, the inventors in particular considering the use of a corona treatment as advantageous. A method according to the invention is preferred, wherein the plasma is a piezoelectric direct discharge plasma or a plasma generated by corona discharge.Preference is given to a method according to the invention, wherein the activation of the second film surface with the plasma is effected by corona treatment, and / or wherein the activation of the base substrate surface with the plasma is effected by corona treatment.In order to reduce the apparatus complexity required, it is expedient to use the same plasma method for the activation of the two surfaces. A method according to the invention is accordingly preferred, wherein the activation of the second film surface and the base substrate surface takes place with the same type of plasma.However, the experiments by the inventors have shown that the selective use of different plasma conditions, for example when using different process gases, enables the adhesion between the film element and the base substrate to be increased in a targeted manner, which is attributed to the different reactive species. This advantageously makes it possible to control the adhesion between the two semi-finished products by selecting the plasmas used for activation. For some applications, despite the higher outlay on apparatus, a method according to the invention is thus preferred, wherein the activation of the second film surface and the base substrate surface takes place with different types of plasma.With regard to the activation intensity, a method according to the invention is preferred, wherein the second film surface and / or the base substrate surface, preferably the second film surface and the base substrate surface, are moved relative to the plasma source at a speed in the range from 0.1 to 100 m / min, preferably in the range from 5 to 80 m / min. The activation time is then the time when the plasma acts on the foil and base substrate. In practice, the inventors propose to work "roll-to-roll" or "wafer-to-wafer". This means that the plasma equipment remains stationary and the film surface or the base substrate surface is driven through under the plasma equipment.Those skilled in the art will understand that plasma activation on the treated surface produces reactive species which can react with time so that the level of activation decreases with time. In accordance with the expert's understanding, it is expedient to rapidly bring about the connection of the film element to the base substrate after the plasma activation, wherein the activation is particularly preferred "in situ", i.e. directly in the process of connection. A method according to the invention is accordingly preferred, wherein the activation of the second film surface and / or the activation of the base substrate surface with the respective plasma, preferably the activation of the second film surface and the activation of the base substrate surface, takes place immediately before the application of the film element to the base substrate, wherein the time interval between the activation with the plasma and the application is in each case preferably less than 8 h, particularly preferably less than 2 h, very particularly preferably less than 1 h, particularly preferably less than 15 min, further preferably less than 5 min, very preferably less than 1 min, for example less than 15 s.In addition to the tackiness defined above, the inventors have found that further surface properties of the film element can also be optimized in order to achieve a particular suitability for the LIFT process. In particular, it has been found that the surface hardness should not be selected to be too high. However, it has also been found at the same time that, at low hardness, the secure absorption of the microPTFE can suffer greatly if they penetrate too far into the substrate and can potentially be ejected again, with the result that there is a conflict of goals with respect to the hardness, which can be adjusted in particular via the filler content. In this respect, preference is given to a method according to the invention, wherein the planar film element on the first film surface and / or the second film surface, preferably on the first film surface and the second film surface, has a Shore A hardness according to DIN ISO 7619-1 from 2012 in the range from 5 to 45, preferably in the range from 10 to 40, particularly preferably in the range from 15 to 35, very particularly preferably in the range from 20 to 30.In addition, the inventors have found that it is favorable for reliable recording of the microLED if the first film surface is as smooth as possible and has as few unevennesses as possible, by means of which a spin-on microLED could be deflected unintentionally. Preference is given to a method according to the invention, wherein the planar film element has a mean roughness according to DIN EN ISO 4287:2010 on the first film surface in the range from 100 to 500 nm, preferably in the range from 120 to 450 nm, particularly preferably in the range from 140 to 400 nm.As explained above, it is necessary with regard to the handling properties of the film elements that fillers, in particular amorphous silicon dioxide, are used in the film material. In the light of the above statement that inherently actually smooth surfaces would be preferred, however, this entails the disadvantage that fillers protrude from the silicone rubber and can thus contribute to a rougher surface.In this respect, the inventors have identified a particularly advantageous process procedure for the production or provision of the corresponding film elements. The inventors have found it particularly advantageous if these film elements are formed by coating solution on a smooth substrate, in particular a liner known from the field of adhesive tape production. Corresponding liners are well known to the person skilled in the art in the field of adhesive technology and regularly have a particularly smooth surface which is optionally provided with a so-called release coating, for example a siliconized surface.This production produces a film element which has a very smooth surface on the side facing the liner, which is largely free of protruding fillers and which is thus optimally suitable as the first film surface. Synergistically, the surface exposed on the liner is presented optimally to be plasma activated as the second film surface, which liner can be advantageously used to position the film element smoothly and precisely on the base substrate.Depending on the composition of the film material and the coating used, the surface exposed on the liner, after removal of the solvents as a result of protruding fillers, will also be appreciably rougher than the surface facing the liner. This increased roughness leads in a synergistic manner to an increased surface and, due to the fact that the adhesion is mostly proportional to the surface, to a particularly advantageous adhesion effect on the base substrate, which assists plasma activation.Preference is thus given firstly to a method according to the invention, wherein the planar film element is produced in method step a) by applying the film material to the receiving surface of a release liner, preferably by means of coating of solution, wherein the side of the planar film element facing away from the release liner is the second film surface.As an alternative to this, a method according to the invention is preferred when shopping suitable starting film elements, wherein the sheet-like film element in method step a) is provided by a starting film element comprising: A) one or more sheet-like film elements having a first film surface and a second film surface, wherein the sheet-like film element consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element has an adhesive force on the first film surface in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 on the basis of DIN EN 1939:2003, and C) a release liner having a receiving surface,wherein the one or more sheet-like film elements are arranged with the first film surface on the receiving surface of the release liner.In both embodiments, a method according to the invention is particularly preferred, wherein the flat film element has a lower average roughness value on the first film surface according to DIN EN ISO 4287:2010 than on the second film surface.In order to utilize the advantageous stabilization by the liner in the application process, the inventors find it particularly advantageous to remove the corresponding liner only after the connection of the film element to the base substrate. Preference is therefore given to a method according to the invention, wherein the release liner is removed from the planar film element after the film element has been applied to the base substrate.In the light of the above explanations, it is understood by the person skilled in the art that the invention also relates to a corresponding starting film element. The invention relates more precisely to a starting film element for providing a sheet-like film element in a method according to the invention, comprising: A) one or more sheet-like film elements having a first film surface and a second film surface, wherein the sheet-like film element consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element has an adhesive force on the first film surface in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 on the basis of DIN EN 1939:2003, and C) a release liner having a receiving surface,wherein the one or more sheet-like film elements are arranged with the first film surface on the receiving surface of the release liner.In addition to the film element, the base substrate which is to be coated with the film element is of substantial importance. By omitting adhesion-promoting layers or similar elements, the multilayer receiver material will usually be a merely two-layer receiver material which consists of the base substrate and the film element arranged thereon. Thus, for most applications, a method according to the invention is preferred, wherein the multilayer receiver material consists of the sheet-like film element and the base substrate, and / or wherein the sheet-like film element directly contacts the base substrate, wherein in particular no adhesive is arranged between the sheet-like film element and the base substrate.The base substrate for use in the present invention is selected by the skilled worker above all in the light of the processing methods used by him and the substrate is matched, for example, to the wavelengths of the laser used in the LIFT method. With regard to shape and dimensioning, the person skilled in the art is freely orientated on the devices available to him. With regard to the typical substrates in the field of MicroLED technology, the inventors have estimated that in the very vast majority of cases they are typical wafers, sapphire wafers in particular being particularly preferred because of their laser transparency. Sapphire is a variant of the mineral corundum, i.e. aluminum oxide. Thus, a method according to the invention is preferred first, wherein the base substrate is a wafer. In addition or alternatively, a method according to the invention is preferred, wherein the base substrate consists to a mass fraction of 80% or more, preferably 90% or more, particularly preferably 95% or more, very particularly preferably 99% or more, in particular preferably 100% of a base substrate material selected from the group consisting of crystals and glasses, preferably selected from the group consisting of synthetic corundums, particularly preferably sapphire.With regard to the dimensions, the typical wafers which are customary in the field of technology are particularly suitable. An example is a method according to the invention, wherein the base substrate has an average thickness in the range from 500 to 5000 μm, preferably in the range from 600 to 4000 μm, particularly preferably in the range from 700 to 3000 μm, very particularly preferably in the range from 800 to 2000 μm, particularly preferably in the range from 900 to 1500 μm. By way of example, additionally or alternatively for classical wafers having a diameter in the range from 5.08 cm (2 inches) to 30.48 cm (12 inches), a method according to the invention is provided, wherein the base substrate surface has a surface area of 10 cm 2 or more, alternatively of 50 cm 2 or more, further alternatively of 100 cm 2 or more, again alternatively of 200 cm 2 or more, in particular alternatively of 600 cm 2 or more.A method according to the invention is particularly preferred, wherein the planar film element and the base substrate surface have a corresponding basic shape, wherein the planar film element and the base substrate surface are preferably both circular. Particularly preferred additionally or alternatively is a method according to the invention, wherein the planar film element has a smaller area than the base substrate surface, wherein the edge of the film element in the multilayer receiver material is preferably spaced apart from the edge of the base substrate surface.The multilayer receiver materials according to the invention, but at least the corresponding film elements, should be produced according to the inventors' judgment for the best possible suitability in the handling of MicroLED in a clean room. A method according to the invention is thus preferred, wherein the planar film element is produced in a clean room in method step a), and / or wherein method steps a) to e) of the method are carried out in a clean room.As has been emphasized several times above, the suitability of the multilayer receiver materials according to the invention for use in the LIFT method is dependent on adequate transparency of the receiver materials to electromagnetic radiation of the wavelength used by the laser used. This is advantageously possible due to the specific film material and the design freedom in the selection of the base substrate in combination with the compound via double plasma activation. The specific film material has no absorption or no absorption of any significance for the wavelengths relevant in practice, so that advantageous transmissions can be obtained, in particular for the relevant film thicknesses, in particular also because the corresponding film elements can be produced in an efficient manner with a particularly low defect content. The double plasma activation used for connecting the film element and the base substrate advantageously not only makes the use of absorbing and / or scattering intermediate layers superfluous, but also results in even a very slight impairment of the laser transparency at best. The fine adjustment is carried out by the skilled person in the production of corresponding receiver materials in the light of the later application, so that he selects, for example, possible additives of the film material such that they do not show any relevant absorption in the wavelength range relevant for the later application. In practice, this tuning will be effected primarily on the receiver materials as a whole, it being implicitly evident that the individual components also exhibit a corresponding transmission.A method according to the invention is preferred, wherein the multilayer receiver material has, for electromagnetic radiation of a predefined target wavelength occurring orthogonally to the first film surface, at least in sections, preferably substantially over the entire receiver material, a transmission, measured by means of UV / VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more. A method according to the invention is preferred in an analogous manner, wherein the planar film element has a transmission, measured by means of UV / VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more, for electromagnetic radiation of a predefined target wavelength occurring orthogonally onto the first film surface, at least in sections, preferably substantially over the entire film element. A method according to the invention is also preferred in an analogous manner, wherein the base substrate has, for electromagnetic radiation of a predefined target wavelength occurring orthogonally to the base substrate surface, at least in sections, preferably substantially over the entire base substrate, a transmission, measured by means of UV / VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more. In this case, the target wavelength is the wavelength of the laser used in the later LIFT method.In the light of the relevant laser wavelengths and with the aim of being able to use the receiver materials with a wide range of possible lasers, particularly preferred radiation permeabilities result.A method according to the invention is namely preferred first, wherein the multilayer receiver material has, for electromagnetic radiation of a wavelength in the range from 10 to 550 nm, preferably in the range from 100 to 350 nm, particularly preferably in the range from 200 to 300 nm, occurring orthogonally to the first film surface, at least partially a transmission, measured by means of UV-VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more. Preferably, a method according to the invention is attached thereto, wherein the planar film element has, for electromagnetic radiation of a wavelength in the range from 10 to 550 nm, preferably in the range from 100 to 350 nm, particularly preferably in the range from 200 to 300 nm, occurring orthogonally to the first film surface, at least partially a transmission, measured by means of UV-VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more. Also preferably linked to this is a method according to the invention, wherein the base substrate has, for electromagnetic radiation occurring orthogonally to the base substrate surface and having a wavelength in the range from 10 to 550 nm, preferably in the range from 100 to 350 nm, particularly preferably in the range from 200 to 300 nm, at least partially a transmission, measured by means of UV-VIS spectroscopy, of 95% or more, preferably 98% or more, particularly preferably 99% or more.The setting of a high transparency advantageously makes it possible to monitor the LIFT method by complicated optical control systems under microscopic methods in a controlled manner at μm level, to detect any fault in the receiver material or its components and thus to achieve a so-called "MassTransfer YIELD" of up to 99.9999%.In the light of the above disclosure, it is understood that the invention also relates to a multilayer receiver material and to the use thereof as receiver material in the processing of MicroLED by means of laser-induced forward transfer methods.The invention thus also relates to a multilayer receiver material, preferably produced or producible by the method according to the invention, comprising: A. a sheet-like film element having a first film surface and a second film surface, wherein the sheet-like film element consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers,wherein the flat film element has an adhesive force on the first film surface in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 based on DIN EN 1939:2003, andB. a base substrate having a base substrate surface,wherein the planar film element is arranged with the second film surface on the base substrate surface of the base substrate,wherein the planar film element and the base substrate are bonded to one another, wherein the bonded connection is carried or brought about by the reaction of plasma-activated surface components of the second film surface with the base substrate surface and of plasma-activated surface components of the base substrate surface with the second film surface,wherein the surface of the multi-layer receiver material is partially formed by the first film surface.Preference is given here to a multilayer receiver material according to the invention, wherein the bond strength between the sheet-like film element and the base substrate is in the range from 1 MPa or more, preferably 2 MPa or more, particularly preferably 4 MPa or more, measured in a dynamic tensile shear test based on DIN-EN 1465 at 23° C. and 50% relative humidity for a test speed of 1 mm / min.The invention furthermore relates to the use of a multilayer receiver material according to the invention as receiver material in the processing of MicroLED by means of laser-induced forward transfer methods.Also disclosed in a manner depending on the use according to the invention is a method for processing MicroLED with a receiver material according to the invention, comprising the steps: x) producing or providing a plurality of MicroLED on the surface of a production substrate, y) transferring the plurality of MicroLED from the surface of the production substrate to the first film surface of the receiver material by means of laser-induced forward transfer (LIFT) methods, and z) transferring the plurality of MicroLED arranged on the first film surface of the receiver material to a receiver substrate by means of laser-induced forward transfer (LIFT) methods.The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the attached figures. The following are shown: FIG. 1 shows a schematic visualization of method steps a) and b) of the method according to the invention in a preferred embodiment; FIG. 2 shows a schematic visualization of method steps c) and d) of the method according to the invention in a preferred embodiment; FIG. 3 shows a schematic visualization of method step e) of the method according to the invention in a preferred embodiment; FIG. 4 is a schematic visualization of the use of a multi-layer receiver material in a laser-induced forward transfer process in MicroLED imaging; and FIG. 5 is a schematic visualization of the use of a multi-layer receiver material in a laser-induced forward transfer process in dispensing MicroLED.FIGS. 1, 2 and 3 show a schematic visualization of all method steps of the method according to the invention for producing a receiver material 10 in a preferred embodiment, wherein the method steps in the example shown are carried out in a clean room. In FIGS. 1, 2 and 3, the steps are shown in a perspective side view (left) and a plan view (right), respectively.In FIG. 1, a base substrate 18 and a planar film element 12 are provided. In the example shown in FIG. 1, the base substrate 18 provided is an approximately 5 cm (2-inch) sapphire wafer having an average thickness of 1 mm and has a planar base substrate surface 20 which is provided for later receiving the planar film element 12.In the preferred example shown, the planar film element 12 is provided by a starting film element 26 which comprises the planar film element 12 on a receiving surface 22 of a release-coated release liner 24. The planar film element 12 is arranged with a first film surface 14 on the receiving surface 22 in such a way that the second film surface 16, which is opposite the first film surface 14, points away from the release liner 24 and is accordingly accessible, whereas the first film surface 14 is covered by the release liner 24.The planar film element 12 shown has a thickness of 75 μm and corresponds with respect to the circular basic shape to the basic shape of the sapphire wafer. In this case, the diameter of the flat film element 12 is smaller by approximately 5 to 10%, so that although the predominant part of the surface of the 5 cm wafer (2 inch wafer) can be covered by the flat film element 12, an edge spacing can be provided in this case.In the example shown, the planar film element 12 consists entirely of a film material which is essentially entirely composed of silicone rubber admixed with pyrogenic amorphous silicon dioxide, the proportion by mass of the filler being approximately 40%. The starting film element 26 was preferably prepared from solution by coating the release liner 24 so that the first film surface 14 is particularly smooth, while the rear-side second film surface 16 has a rougher surface as a result of the drying and loss in volume.Both the first film surface 14 and the second film surface 16 have a relatively low bond strength in the range from about 15 cN / cm to 25 cN / cm, measured according to the test method J0PM002 on the basis of DIN EN 1939:2003 as described above, so that an adhesive layer cannot be mentioned here in the conventional sense. However, this adhesive force is sufficient to temporarily fix the microPTFE 30 to be taken up and subsequently also to release it again. However, this adhesive force is not sufficient to fix the sheet-like film element 12 reliably and permanently to the base substrate 18.FIG. 2 schematically shows, in a manner linked to FIG. 1, the method steps c) and d) of the method according to the invention, which address the problem of the connection of the sheet-like film element 12 and the base substrate 18, namely the contacting of the second film surface 16 and the base substrate surface 20 with a plasma, which is generated in the example shown for both surfaces 16, 20 by means of a corona treatment, in order to obtain a plasma-activated second film surface 16 and a plasma-activated base substrate surface 20, which is indicated by the arrows.As visualized in FIG. 3, the plasma-activated second film surface 16 is preferably applied directly following the plasma treatment, i.e. after a few seconds, to the plasma-activated base substrate surface 20 of the base substrate 18 in order to obtain the receiver material 10, wherein the planar film element 12 can be advantageously stabilized by the release liner 24. The release liner 24 is removed after the application of the sheet-like film element 12.FIGS. 4 and 5 show the use of a receiver material 10 produced in this way in the processing of MicroLEDs 30, and FIG. 4 shows a production substrate 28, which is a typical epi wafer, having a multiplicity of MicroLEDs 30, which are transferred to the first film surface 14 of the receiver material 10 by means of laser-induced forward transfer methods. Here, the laser beam is shown as a dashed beam which runs through the production substrate 28, the local evolution of gas produced by the action of the laser being indicated by two "bulges". The microPTFEs 30 meet the particularly smooth first film surface 14 of the receiver material 10 optimized with regard to the recording properties and are fixed there in a sufficiently firm manner.FIG. 5 shows the subsequent transfer of the plurality of microLEDs 30 arranged on the first film surface 14 of the receiver material 10 onto a receiver substrate 32 by means of laser-induced forward transfer (LIFT) methods, for example in the context of the production of a display. For this purpose, the planar film element 12 and the underlying base substrate 18, which together form the receiver material 10, have a substantially complete transparency for electromagnetic radiation of the laser occurring orthogonally to the first film surface 14 or the base substrate surface 20, so that the receiver material 10 can also be irradiated without absorption for EUV and DUV lasers.List of reference characters10 Multilayer Receiver Material 12 Sheet-like Film Element 14 First Film Surface 16 Second Film Surface 18 Base Substrate 20 Base Substrate Surface 22 Receiving Surface 24 Release Liner 26 Starting Film Element 28 Production Substrate 30 MicroLED 32 Receiver Substrate

Claims

Method for producing a multilayer receiver material (10), comprising the method steps: a) producing or providing a sheet-like film element (12) having a first film surface (14) and a second film surface (16), wherein the sheet-like film element (12) consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element (12) has an adhesive force on the first film surface (14) in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 on the basis of DIN EN 1939:2003, b) producing or providing a base substrate (18) having a base substrate surface (20), c) activating the second film surface (16) with a plasma to obtain a plasma-activated second film surface (16), d) activating the base substrate surface (20) with a plasma to obtain a plasma-activated base substrate surface (20), e) applying the film element (12) with the plasma-activated second film surface (16) to the plasma-activated base substrate surface (20) of the base substrate (18) to obtain the multilayer receiver material (10), wherein the surface of the multilayer receiver material (10) is formed partly by the first film surface (14).The method of claim 1, wherein the sheet-like film element (12) has an average thickness in the range of 2 to 500 μm.Method according to either of Claims 1 and 2, wherein the planar film element (12) has an adhesive force on the first film surface (14) in the range from 0.5 cN / cm to 100 cN / cm.Method according to one of Claims 1 to 3, wherein the planar film element (12) has a Shore A hardness according to DIN ISO 7619-1 on the first film surface (14) and / or the second film surface (16).Method according to one of Claims 1 to 4, wherein the planar film element (12) has a lower average roughness value on the first film surface (14) in accordance with DIN EN ISO 4287:2010 than on the second film surface (16).Method according to one of Claims 1 to 5, wherein the planar film element (12) is produced in method step a) by applying the film material to the receiving surface (22) of a release liner (24), wherein the side of the planar film element (12) facing away from the release liner (24) is the second film surface (16).Method according to one of Claims 1 to 5, wherein the planar film element (12) is provided in method step a) by a starting film element (26) comprising: A) one or more planar film elements (12) having a first film surface (14) and a second film surface (16), wherein the planar film element (12) consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the planar film element (12) has an adhesive force on the first film surface (14) in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 in accordance with DIN EN 1939:2003, and C) a release liner (24) having a receiving surface (22), wherein the one or more sheet-like film elements (12) are arranged with the first film surface (14) on the receiving surface (22) of the release liner (24).Method according to either of Claims 6 and 7, wherein the release liner (24) is removed from the planar film element (12) after the planar film element (12) has been applied to the base substrate (18).Method according to one of Claims 1 to 8, wherein the base substrate (18) consists, to a mass fraction of 80% or more, of a base substrate material selected from the group consisting of synthetic corundums.Method according to one of Claims 1 to 9, wherein the activation of the second film surface (16) with the plasma is effected by corona treatment, and / or wherein the activation of the base substrate surface (20) with the plasma is effected by corona treatment.Multilayer receiver material (10), preferably produced or producible by the method according to one of Claims 1 to 10, comprising: A. a sheet-like film element (12) having a first film surface (14) and a second film surface (16), wherein the sheet-like film element (12) consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element (12) has an adhesive force on the first film surface (14) in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 on the basis of DIN EN 1939:2003, and B. a base substrate (18), having a base substrate surface (20), wherein the planar film element (12) is arranged with the second film surface (16) on the base substrate surface (20) of the base substrate (18), wherein the planar film element (12) and the base substrate are bonded to one another, wherein the bonded connection is carried or effected by the reaction of plasma-activated surface constituents of the second film surface (16) with the base substrate surface (20) and of plasma-activated surface constituents of the base substrate surface (20) with the second film surface (16), wherein the surface of the multilayer receiver material (10) is formed partly by the first film surface (14).Starting film element (26) for providing a sheet-like film element (12) in a method according to any of claims 1 to 10, comprising: A) one or more sheet-like film elements (12) having a first film surface (14) and a second film surface (16), wherein the sheet-like film element (12) consists at least partially of a film material, wherein the film material comprises: i) one or more silicone rubbers, and ii) one or more fillers, wherein the sheet-like film element (12) has an adhesive force on the first film surface (14) in the range from 0.2 cN / cm to 120 cN / cm, measured according to the test method J0PM002 in accordance with DIN EN 1939:2003, and C) a release liner (24) having a receiving surface (22), wherein the one or more sheet-like film elements (12) are arranged with the first film surface (14) on the receiving surface (22) of the release liner (24).Use of a multilayer receiver material according to claim 11 as receiver material in the processing of MicroLED by means of laser-induced forward transfer methods.

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