Method for the production and / or handling of a metal-ceramic substrate, a metal-ceramic substrate, a plant for the production of metal-ceramic substrates and a database for metal-ceramic substrates

Abstract

Methods for producing and / or handling metal-ceramic substrates (1, 10), comprising: - Providing a metal layer (12) and a ceramic layer (11) - Bonding the metal layer (12) to the ceramic layer (11) to produce a metal-ceramic substrate (1, 10), - Determining a surface finish in a subsection, preferably in a defined subsection, of a surface of the metal layer (12), the ceramic layer (11) and / or the metal-ceramic substrate (1, 10), and - Use of the specific surface texture as a distinguishing feature (21, 22, 23).

Description

[0001] The present invention relates to a method for producing and / or handling a metal-ceramic substrate as well as to a metal-ceramic substrate, a plant for producing metal-ceramic substrates and a database for metal-ceramic substrates.

[0002] Metal-ceramic substrates are well known in the art, for example, as printed circuit boards or circuit boards. Typically, connection pads for electrical or electronic components and conductor tracks are arranged on one component side of the metal-ceramic substrate, with the electrical components and conductor tracks being interconnectable to form electrical circuits. Key components of metal-ceramic substrates are an insulating layer made of a ceramic material and a metal layer bonded to the insulating layer. Due to their comparatively high insulation strength, insulating layers made of ceramic material have proven particularly advantageous. By structuring the metal layer, conductor tracks and / or connection pads for the electrical or electronic components can be realized.

[0003] EP 3 185 655 A1 discloses a method in which an unstructured metal-ceramic substrate is provided and provided with a personalized coding. Using the coding, information can be assigned to the metal-ceramic substrate, which can be accessed when reading the coding. Examples of information include information about defects in the metal-ceramic substrate, a manufacturing date, or a batch number.

[0004] Based on this prior art, the present invention aims to further improve the production of metal-ceramic substrates, in particular with regard to their traceability and the quality of the manufactured metal-ceramic substrates, as well as with regard to avoiding disadvantages resulting from the markings known in the prior art.

[0005] This object is achieved by a method for forming a metal-ceramic substrate according to claim 1 and a metal-ceramic substrate according to claim 8, a system according to claim 9 and a database according to claim 10. Further advantages and features of the invention emerge from the subclaims as well as the description and the attached figures.

[0006] According to a first aspect of the present invention, there is provided a method for producing and / or handling metal-ceramic substrates, comprising: - Providing a metal layer and a ceramic layer, - Bonding the metal layer to the ceramic layer to produce a metal-ceramic substrate, - determining a surface quality in a defined subsection of a surface of the metal layer, the ceramic layer and / or the metal-ceramic substrate, and - Use of the specific surface texture as a marking.

[0007] Compared to the procedures known from the prior art for the individual identification of metal-ceramic substrates, in particular the metal layer and the ceramic layer, the invention provides that the surface quality of the metal-ceramic substrate, the ceramic layer and / or the metal layer is used to serve as a marking. In this case, the individuality of the surface quality, in particular at the microscopic level, is used. This in turn avoids the need to embed a marking in the metal-ceramic substrate, the metal layer and / or the ceramic layer, i.e., it is possible to avoid embedding the marking in the metal-ceramic substrate in an additional work step.The process is particularly advantageous because it eliminates an additional work step and, in addition, any usable area is not compromised by the coding medium or the applied marking. Furthermore, it is advantageous to apply individual marking. This is particularly advantageous in the mass production of metal-ceramic substrates.

[0008] A subsection is understood, in particular, to be a specific, defined area on the metal layer and / or the ceramic layer and / or the metal-ceramic substrate. In this case, not only the position of the subsection is preferably defined, but also its size. Subsections are preferably defined in terms of size and position for all metal-ceramic substrates for each metal layer, ceramic layer, and each metal-ceramic substrate depending on a process step. In other words, during each process step in the production of the metal-ceramic substrate, the surface quality is recorded at the same position for all metal-ceramic substrates. Such a defined area, which is preferably defined for each process step in the production of the metal-ceramic substrate, allows for quick and inexpensive reading of the surface quality used as an identifier.Alternatively, it is conceivable that – for each metal-ceramic substrate – after a process step, an optimal subsection is searched for, the position of which is stored along with the information on the surface texture. The position and / or size of the subsection are then stored together with the recorded surface texture for the individual metal-ceramic substrate and used as additional information for identification. During the readout, the entire metal-ceramic substrate is scanned, scanned for the used surface texture, and then compared with the stored position and / or size.

[0009] To prevent a surface texture from becoming obscured in the defined area, for example, due to contamination caused during manufacturing and / or handling, it is conceivable that at least one additional sub-area with its surface texture be used. The sub-area and the additional sub-area are particularly preferably spaced apart to reduce the likelihood that the sub-area and the additional sub-area are affected by the same contamination.

[0010] The production of a metal-ceramic substrate preferably involves bonding the metal layer to the ceramic layer. Handling preferably includes process steps that are carried out following bonding. These include, for example, structuring the metal layer to form a component metallization, polishing, surface cleaning, packaging, and / or nickel plating.

[0011] Preferably, an identification by a surface quality is assigned to the metal layer and / or the ceramic layer as starting materials prior to bonding. The information assigned to the metal layer and / or the ceramic layer is then likewise assigned to the identification determined as a surface quality on the metal-ceramic substrate on the metal layer and / or the ceramic layer. Information assigned to the identification of the metal-ceramic substrate includes, for example, the bonding, such as a type of bonding and / or certain bonding parameters, such as atmosphere, temperature, temperature profile and / or pressure during bonding.

[0012] The use of the marking is preferably understood to mean any process that is based on an identification of the metal-ceramic substrate, the metal layer and / or the ceramic element based on the surface quality in the sub-section. The identification is preferably used to control a subsequent process based on the information assigned to the marking. It is also conceivable that information about the metal-ceramic substrate, the ceramic layer and / or the metal layer is added after a process step. For example, a result of the process step is classified. This can be used, for example, to ensure that the metal-ceramic substrate is sorted out before the subsequent process step or at the next possible time in the production line, or the subsequent process step is adapted accordingly to take into account the result of a previous process or the connection, e.g. a possible defect.Furthermore, it is conceivable that the stored information, particularly together with the results of the individual process step, be provided as a data set for later evaluation. This makes it possible, for example, to optimize parameters for subsequent manufacturing processes and / or to identify systematic problems. Preferably, the data set is provided and / or used as a test data set for a machine learning mechanism, such as artificial intelligence, to optimize process parameters based on a comprehensive data set and, particularly preferably, to customize them for individual metal layers, ceramic layers, and / or metal-ceramic substrates.

[0013] For example, the surface texture can be determined in the form of a microscopic image. A square image of the surface in a partial area is conceivable, especially in a top view. Such an image is characterized by a two-dimensional distribution of grayscale and / or colors, which, similar to a QR code, can be used to enable individual assignment to individual ceramic substrates, metal layers and / or metal-ceramic substrates. It is also conceivable that the surface texture is identified based on certain parameters and that these parameters could be used for further determination. For example, the surface roughness could be used for this purpose. It is also conceivable that the surface texture is converted into a code, in particular a binary code. This can be stored on a storage medium while requiring less storage space.This proves particularly advantageous in the case of mass production, as it allows for individual marking without the need for extensive, specially designed storage media. It also allows for faster comparison, which significantly speeds up identification based on the marking.

[0014] Preferably, the marking or coding is intended to be used within the framework of a manufacturing process or within the framework of a subsequent step after the formation of the marking in the manufacturing process and / or for tracing the respective metal-ceramic substrate after the production of the metal-ceramic substrate. Preferably, the marking or coding is already implemented before the structuring of the at least one metal layer in the metal-ceramic substrate. For example, it is conceivable that the respective coding is assigned to any defects and / or errors in the connection of the at least one metal layer to the insulation element, preferably their position or orientation, and / or a batch number and / or a material specification relating to the at least one metal layer and / or the insulation element and / or the entire metal-ceramic substrate.Preferably, a database is provided in which codes or the marking and information, in particular information regarding possible locations of a defect and / or for identifying the metal-ceramic substrate, are assigned to one another and stored. The marking is preferably an individual marking that differs, for example, from metal-ceramic substrate to metal-ceramic substrate.

[0015] Preferably, it is provided that a marking is provided in a large card or a metal-ceramic base substrate, and all information about all defects within the large card is assigned to the marking, so that the positioning of the structuring and / or the predetermined breaking lines, along which the large card is divided into individual metal-ceramic substrates, can be oriented accordingly. This allows isolation trenches and / or predetermined breaking points to be placed, preferably in the area of ​​defects or cavities. This reduces the probability of forming a defective metal-ceramic substrate. For this purpose, it is preferably provided that the identified defects, which are associated in particular with the coding or the marking, are evaluated accordingly by an evaluation device in order to possibly cause a shift in the intended structural pattern or structuring during the manufacturing process.

[0016] The metal-ceramic substrate is preferably designed as a printed circuit board in which, in the manufactured state, the at least one metal layer which is connected to the insulation element is structured. For example, it is provided for this purpose that after the connection step, structuring is also carried out, for example by lasering, etching and / or mechanical processing, with which conductor tracks and / or connections for electrical or electronic components are realized. It is preferably provided that on a manufactured metal-ceramic substrate, on the insulation element, on the side opposite the metal layer, a further metal layer, in particular a back-side metallization and / or a cooling element, is provided. The back-side metallization preferably serves to counteract deflection and the cooling element serves to effectively dissipate heat which is generated during the operation of electrical orelectronic components that are connected to the circuit board or the metal-ceramic substrate.

[0017] Conceivable materials for the at least one metal layer and / or the at least one further metal layer in the metal-ceramic substrate or insulation element include copper, aluminum, molybdenum, tungsten, nickel, and / or their alloys, such as CuZr, AlSi, or AlMgSi, as well as laminates such as CuW, CuMo, CuAl, and / or AlCu, or MMC (metal matrix composite), such as CuW, CuMo, or AlSiC. Furthermore, it is preferably provided that the at least one metal layer on the manufactured metal-ceramic substrate is surface-modified, in particular as component metallization. A possible surface modification could, for example, be a sealing with a precious metal, in particular silver and / or gold, or (electroless) nickel or ENIG ("electroless nickel immersion gold"), or edge encapsulation on the metallization to suppress crack formation or crack widening.

[0018] The ceramic layer preferably comprises Al2O3, Si3N4, AlN, an HPSX ceramic (i.e., a ceramic with an Al2O3 matrix containing an x-percent ZrO2 content, for example Al2O3 with 9% ZrO2 = HPS9 or Al2O3 with 25% ZrO2 = HPS25), SiC, BeO, MgO, high-density MgO (> 90% of the theoretical density), TSZ (tetragonally stabilized zirconium oxide) as the material for the ceramic. It is also conceivable for the ceramic layer to be designed as a composite or hybrid ceramic, in which, in order to combine various desired properties, several ceramic layers, each differing in terms of their material composition, are arranged one above the other and joined together to form an insulating element, i.e., preferably a ceramic layer. It is also conceivable that a metallic intermediate layer is arranged between two ceramic layers in the insulation element, which is preferably thicker than 1.5 mm and / or thicker than the two ceramic layers in total.Preferably, a ceramic that is as thermally conductive as possible is used to ensure the lowest possible thermal resistance.

[0019] Preferably, the surface quality relates to a grain size in the sub-section. In particular, this takes advantage of the fact that the metal-ceramic substrates, both in the metal layer and in the ceramic layer, have a certain grain size due to the manufacturing method used to bond the metal layer to the ceramic element. For example, the marking is intended to use the individual grain boundary lines to be used as a marking. It is also conceivable to record a grain size distribution and use this together with other parameters, for example, as a marking. By using the grain boundary lines, which are particularly individual for each metal-ceramic substrate, in particular each metal layer and each ceramic layer and each metal-ceramic substrate layer.However, a particularly simple method can be provided that allows for a very individual assignment.

[0020] In particular, the marking is adapted to a changing surface quality in the subsection. This advantageously makes it possible to take into account changes in the surface quality of the ceramic layer, the metal layer, and / or the metal-ceramic substrate due to process or manufacturing steps. For example, it is advantageous if, after a process or processing step, the surface quality in the specified subsection is re-recorded and used for further marking. In other words, after a manufacturing process, the surface quality is determined again in the subsection to replace the previous surface quality in the subsection.This ensures that the surface finish can continue to be used as a marking, even if, for example, modifications to the surface finish are to be expected due to a manufacturing step.

[0021] This can occur particularly if the manufacturing step involves bonding, where, due to the high temperatures, corresponding grain growth or a change in grain size is to be expected. Preferably, the subsection is modified. It is also conceivable that the position and / or size of the subsection may be modified due to circumstances arising from the manufacturing process. This allows the optimal position of the subsection to be determined for the respective manufacturing process to ensure the marking.It is conceivable, for example, that the position in a first sub-section is changed to a second sub-section which is no longer congruent with the first sub-section if a modification has taken place in the first sub-section during the manufacturing process, as a result of which this first sub-section can no longer be used meaningfully for marking.

[0022] Preferably, the marking is used to control process steps. For example, the information stored with the marking is used to control or influence the process steps during handling and processing of the manufactured metal-ceramic substrate. For example, it is conceivable that a defect or similar is stored as the first piece of information and that the position or orientation of the metal-ceramic substrate, for example for subsequent structuring to create conductor tracks, is stored as the first piece of information depending on the position of the defect. In this way, for example, the partial area of ​​the metal layer in which a defect occurred during the bonding process can be detached and removed again without affecting the actual essential track paths in the manufactured substrate.

[0023] Preferably, the surface of the metal-ceramic substrate is free of any modifications embedded in the metal-ceramic substrate that serve as a marking. This advantageously eliminates the need for additional processing steps, as well as the need for structuring and / or modifications that, for example, limit the usable space for the metal-ceramic substrate in its finished state.

[0024] It is preferably provided that the metal-ceramic substrate comprises a marking as a large card or as a base card, ie as a metal-ceramic base substrate, and / or as an isolated substrate.

[0025] The present invention further relates to a metal-ceramic substrate produced using the process according to the invention. All properties and advantages described for the process can be applied analogously to the metal-ceramic substrate, and vice versa.

[0026] A further subject of the present invention is a system for carrying out the method according to the invention for producing and / or handling a metal-ceramic substrate. All properties and advantages described for the method can be applied analogously to the system, and vice versa.

[0027] In particular, the system comprises an evaluation device and a readout device designed to register and compare surface characteristics. Preferably, a database is provided for storing the surface characteristics used as a marking, for example, as a binary code, a QR code, or an image, and for assigning information about the individual metal-ceramic substrate to the stored markings.

[0028] A further subject of the present invention is a database for metal-ceramic substrates according to the invention, which comprises an assignment in which the marking formed as a surface finish is assigned to a metal-ceramic substrate produced using the method according to the invention and is preferably linked to information about the metal layer from which the metal-ceramic substrate was produced, and / or the ceramic layer from which the metal-ceramic substrate was produced, and / or the metal-ceramic substrate. All properties and advantages described for the method can be transferred analogously to the database and vice versa.

[0029] Furthermore, it is conceivable that the stored information, for example, about the raw material used to form the metal-ceramic substrate and / or certain bonding process parameters, could be stored in the database. This would make it possible, for example, to define test data sets that can be used by artificial intelligence to identify which parameters can be used or are useful for a particularly successful and reliable metal-ceramic substrate.

[0030] It shows: Fig. 1: schematic representation of a block diagram to illustrate an exemplary method according to the present invention and Fig. 2 schematic representation of a metal-ceramic substrate with a marking according to an exemplary embodiment of the present invention

[0031] In Fig. 1 is a schematic block diagram illustrating an exemplary method according to the present invention for producing metal-ceramic substrates 1. In the Fig. 1, the metal-ceramic substrates 1 or metal-ceramic base substrates are shown partly in a top view and partly in a side view. Such metal-ceramic substrates 1 preferably serve as carriers for electronic or electrical components that can be bonded to the metal-ceramic substrate 1. Essential components of such a metal-ceramic substrate 1 are a ceramic layer 11 extending along a main extension plane and a metal layer 12 bonded to the ceramic layer 11. The ceramic layer 11 is made of at least one material comprising a ceramic. The metal layer 12 and the ceramic layer 11 are arranged one above the other along a stacking direction S running perpendicular to the main extension plane HSE and are integrally bonded to one another via a bonding surface. In the manufactured state, the metal layer 12 is structured to form conductor tracks or connection points for the electrical components.

[0032] To form the metal-ceramic substrate 1, it is provided that the metal for the metal layer 12 and the ceramic for the ceramic layer 12 are first provided as starting materials. Using a DCB process 20, a DAB process, an active solder process (AMB), hot isostatic pressing (HIP), or a diffusion bonding process (ADB), the metal layer 12 and the ceramic layer 11 are then materially bonded to one another in a furnace 14, and a metal-ceramic base substrate 10 is provided. As a result of material defects or for other reasons, defects 7 or defective areas, such as blowholes or similar, can occur in the metal-ceramic base substrate 11. For example, these defects 7 are identified using a suitable camera 4. The metal-ceramic base substrate 10 is also to be understood as a metal-ceramic substrate of the present invention, namely as a metal-ceramic substrate before its singulation.

[0033] By means of a first marking 21, initial information about the registered defects 7 can be individually assigned to the respective metal-ceramic substrates 1. For example, the registered defects are stored in a database for the first marking 21. In this way, the first marking 21 can be read out at a later time using a reader, and the corresponding information about the defect 7 can be used in the further process for producing the metal-ceramic substrate 1. For example, the defect-related first information includes an arrangement or location of the defect on the metal-ceramic base substrate 11—for example, specified in base-substrate-specific coordinates—a classification (type; shape, etc.) of the defect 7, and / or a size of the defect 7.

[0034] This first information can be advantageously used, for example, during structuring 30 of the metal-ceramic substrate, since this makes it possible, in particular, to avoid the defect 7 being located in an area in which metallization, for example as a conductor track or as a connection area for an electronic component, is provided in the manufactured metal-ceramic substrate 1. In other words: Based on the first information, the structuring of the metal layer 12, in particular of the metal layer 12 of the metal-ceramic base substrate 10, can be designed or configured such that the defect or defect 7 is not part of a relevant structure of the metal layer 12 on the manufactured metal-ceramic substrate 1. It is also conceivable that the placement of the metal-ceramic substrates 1 is chosen such that the defect lies exclusively on one of the metal-ceramic substrates 1, so that the number of metal-ceramic substrates 1 to be excluded can be reduced.For example, it is conceivable that the planned placement of the patterning with respect to the metal-ceramic base substrate 10 is shifted, exchanged, and / or rotated in order to remove the area of ​​the metal layer 12 with the patterning defect 30. This advantageously reduces the amount of waste from unusable metal-ceramic substrates 1. For example, the individual first marking 21 is applied using direct illumination.

[0035] Furthermore, it is preferably provided that the metal-ceramic base substrate 10 bears a single first marking 21, to which all defects on the entire metal-ceramic base substrate 10 are assigned as first information. Furthermore, it is provided that the metal-ceramic base substrate 10 is divided into the individual metal-ceramic substrates 1. For example, the individual metal-ceramic substrates 1 are divided 40 along a predetermined breaking point 18 by breaking and / or with the assistance of laser light. In the example shown, the metal-ceramic base substrate 10 is divided into nine metal-ceramic substrates 1. In this case, it is particularly provided that each metal-ceramic substrate uses a second marking and, for example, that second information is assigned to each metal-ceramic substrate via the second marking 22.Preferably, the second information differs from the first information and does not inform about errors or defects. Instead, the second information preferably relates, for example, to a placement of the metal-ceramic substrate 1 in the metal-ceramic base substrate, material specifications of the starting material, i.e., material specifications for the metal and / or ceramic used, a manufacturing date, a batch number, and / or a quality marking. The corresponding second information can thus be identified by means of the second marking 22 on the finished metal-ceramic substrate 1. Preferably, the second marking 22 serves to trace the metal-ceramic substrate 1.

[0036] Preferably, the association between the second marking 22 and the second information is stored in a further database. In particular, the further database is accessible to third parties and stored, for example, on a server of a network or a cloud. This allows subsequent users of the manufactured metal-ceramic substrate 1 to easily obtain the second information. Furthermore, it is possible to supplement the second information at a later point in time, for example, if further relevant information about the manufactured metal-ceramic substrate 1 emerges after production.

[0037] Furthermore, it is preferably provided that the starting material, i.e. the metal of the metal layer 11 and the ceramic of the ceramic layer 12, uses an identification mark. The third identification mark 23 is preferably assigned a third piece of information. The third piece of information comprises, in particular, material specifications, such as a detailed material composition and / or a batch number, which allows clear traceability. The third piece of information is preferably part of the second piece of information or is automatically transferred into the second piece of information. For example, the third identification mark 23 is read from the starting material and integrated into the second piece of information, stored in the further database. This advantageously allows all manufacturing information on the finished metal-ceramic substrate 1 to be identified and traced.

[0038] In particular, it is provided that a surface quality of a partial area of ​​the metal layer 12, the ceramic layer 11 and / or the metal-ceramic substrate 1, 10 is used as the first marking, second marking and / or third marking. For this purpose, it is preferable to preliminarily record the surface quality of the metal layer 12, the ceramic layer 11 and / or the metal-ceramic substrate 1, 10 in a defined partial area. For example, a microscopic image of the surface of the metal layer 12, the ceramic layer 11 and / or the metal-ceramic substrate 10, 1 is recorded. For example, a microscopic image is conceivable that allows for individual assignment based on color gradients and / or grayscale. For example, a two-dimensional area is recorded, which is used similarly to a QR code to serve as an individual marking for a metal-ceramic substrate 1, 10. The Fig.Figure 2 shows an example of such a section with a surface finish serving as markings 21, 22, 23. It can be seen that a grain pattern or a microscopic image of a copper layer reveals grain boundary patterns that are unique to the respective metal-ceramic substrate 1, 10 and are therefore suitable as markings 21, 22, 23.

[0039] This results in the advantage that no additional coding or marking 21, 22, 23 needs to be embedded in the ceramic layer 11 and / or the metal-ceramic substrate 1, 10. This not only eliminates an additional work step in which this marking 21, 22, 23 would have to be implemented, but also does not impair the manufactured metal-ceramic substrate 1, 10, for example in that the marking 21, 22, 23 determines the installation space or usable space of the manufactured metal-ceramic substrate 1, 10. It is also conceivable, for example, that an evaluation device is provided to read the marking 21, 22, 23, which in particular evaluates a microscopic image and allows an assignment based on numerical values. Also conceivable, for example, is the transfer of the microscopic image into a code, for example a binary code, a barcode, or a two-dimensional QR code.

[0040] It is conceivable that the first marking 21, the second marking 21 and / or the third marking 23 are defined in different subsections of the ceramic layer 11, the metal layer 12 and / or the metal-ceramic substrate 1, 10. In other words, depending on the production step and manufacturing step, the position of the subsection and / or its size can vary and be adapted to ensure the best possible recognition of the metal layer 12, the ceramic element 11 and the metal-ceramic substrate 1, 10. In particular, it is provided that the first information, the second information and / or the third information is stored in a corresponding database and / or further database for a surface quality that is used as a marking.It is conceivable, for example, that a graphic representation of the two-dimensional image of the surface texture is stored in the database, along with the information on the position of the subsection and / or the size of the subsection. This, in turn, is assigned a first and / or second and / or third piece of information. This advantageously makes it possible, for example, to identify and trace the respective metal-ceramic substrate 1, 10 and its material composition at a time during production and / or after production of the metal-ceramic substrate 10, 1. This proves advantageous both in the manufacturing process and for determining manufacturing parameters in subsequent manufacturing processes. Reference symbol: 1.10 Metal-ceramic substrate 4 Camera 7 errors 10 Metal-ceramic base substrate 11 Ceramic layer 12 metal layer 14 Oven 18 Predetermined breaking point 20 DCB procedures 21 first individual marking 22 second individual marking 23 third individual marking 30 Structuring 40 Cutting QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 185 655 A1

[0003]

Claims

[1] A method for producing and / or handling metal-ceramic substrates (1, 10), comprising: - providing a metal layer (12) and a ceramic layer (11), - bonding the metal layer (12) to the ceramic layer (11) to produce a metal-ceramic substrate (1, 10), - determining a surface quality in a partial section, preferably in a defined partial section, of a surface of the metal layer (12), the ceramic layer (11) and / or the metal-ceramic substrate (1, 10), and - Use of the specific surface texture as a marking (21, 22, 23). [2] Method according to claim 1, wherein the surface quality relates to a grain in the partial section, preferably a course of a grain boundary or an arrangement of grains and / or grain boundaries. [3] Method according to one of the preceding claims, wherein the marking (21, 22, 23) is adapted to a changing surface condition in the section. [4] A method according to any one of the preceding claims, wherein the subsection is changed. [5] Method according to one of the preceding claims, wherein a microscopic image of the partial section is taken to read out the marking (21, 22, 23) and / or to determine the surface quality serving as the marking (21, 22, 23). [6] Method according to one of the preceding claims, wherein the marking (21, 22, 23) is used to control process steps in the production and / or handling of the metal-ceramic substrate (1, 10). [7] Method according to one of the preceding claims, wherein the surface of the metal-ceramic substrate (1, 10) is free of a modification embedded in the metal-ceramic substrate (1, 10) serving as a marking (21, 22, 23). [8] Metal-ceramic substrate (1, 10) produced by a method according to one of claims 1 to 7. [9] Plant for producing metal-ceramic substrate (1, 10), wherein the plant is designed to carry out the method according to claims 1 to 7. [10] Database for metal-ceramic substrates (1, 10) according to claim 8, comprising an assignment in which the marking (21, 22, 23) formed as a surface finish is assigned to a metal-ceramic substrate (10) produced by a method according to one of the preceding claims 1 to 7, and is preferably linked to information on the metal layer (12) from which the metal-ceramic substrate (10, 1) was produced, and / or on the ceramic layer (11) from which the metal-ceramic substrate (10, 1) was produced, and / or on the metal-ceramic substrate (1, 10).

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