Method for dividing a metal-ceramic substrate, plant and individual metal-ceramic substrate produced using such a method

Abstract

The invention relates to a method for dividing a metal-ceramic substrate (10), in particular a metal-ceramic substrate (10) provided in the form of a large metal-ceramic card, wherein the metal-ceramic substrate (10) is preferably divided into individual metal-ceramic substrates (1), comprising: - providing a metal-ceramic substrate (10), wherein the metal-ceramic substrate (10) comprises at least one metal layer (21) and a ceramic element (20), - forming a predetermined break line (7), in particular by removing ceramic material from the ceramic element (20), - locally heating the ceramic element (20) in the region of the predetermined break line (7), in particular by means of laser light (15), and - cooling the heated region of the predetermined break line (7) in order to separate the ceramic element (20) along the predetermined break line (7).

Description

[0001] Method for dividing a metal-ceramic substrate, system and metal-ceramic single substrate produced by such a method

[0002] The present invention relates to a method for processing a metal-ceramic substrate, a system for such a method and individual metal-ceramic substrates produced by such a method.

[0003] Electronic modules are well known in the art, for example, as power electronics modules. Such electronic modules typically utilize switchable or controllable electronic components interconnected via conductor tracks on a common metal-ceramic substrate. Key components of the metal-ceramic substrate are an insulation layer, which in the case of the metal-ceramic substrate is made of a material comprising a ceramic, and a metallization layer, which is preferably structured to form conductor tracks and is formed on one component side of the metal-ceramic substrate.

[0004] Typically, a metal-ceramic substrate is realized as a large card, which is separated into smaller metal-ceramic substrates, i.e., individual metal-ceramic substrates, after or before structuring. Such large cards are processed using laser light to produce predetermined breaking lines and / or separation points. The respective metal-ceramic substrates can then be prepared in individual pieces from the large card, e.g., by breaking them out. The use of ultrashort pulse lasers has proven advantageous for this purpose, as described, for example, in WO 2017 / 108 950 A1. Based on this prior art, the present invention sets itself the object of improving, in particular simplifying, the separation of metal-ceramics during separation and of reducing any damaging influence on the metal-ceramic substrate during separation.

[0005] This object is achieved by a method for processing a metal-ceramic substrate according to claim 1, by a system suitable therefor according to claim 9, and by a metal-ceramic individual substrate produced by such a method according to claim 10. Further embodiments can be found in the subclaims and the description.

[0006] According to a first aspect of the present invention, a method for dividing a metal-ceramic substrate, in particular a metal-ceramic substrate provided in the form of a metal-ceramic large card, is provided, wherein the metal-ceramic substrate is preferably divided into individual metal-ceramic substrates, comprising:

[0007] - Providing a metal-ceramic substrate, wherein the metal-ceramic substrate comprises at least one metal layer and one ceramic element,

[0008] - Formation of a debit book line, in particular by removing ceramic material from the ceramic element,

[0009] - local heating of the ceramic element in the area of ​​the predetermined breaking line, in particular by means of laser light, and

[0010] - Cooling the heated area of ​​the predetermined breaking line to separate the ceramic element along the predetermined breaking line.

[0011] Compared to the methods known from the prior art, the invention combines a predetermined breaking line with local heating of the ceramic element in the region of the predetermined breaking line, which is immediately followed by cooling to generate thermomechanical stresses that cause the ceramic element to separate. It has been found that the local heating and the subsequent targeted cooling generate thermomechanical stresses, particularly in the region of the predetermined breaking line, which lead to the ceramic element being separated along the predetermined breaking line. This enables the separation or division of the metal-ceramic substrate into individual metal-ceramic substrates.It has proven particularly advantageous to combine the separation caused by thermomechanical stresses with a predetermined breaking line, as the predetermined breaking line supports or dictates the desired and intended course of the separation. Without the predetermined breaking line, the probability increases significantly that an uncontrolled break will result in the separation not occurring in the desired area, i.e., the desired separation edge between two divided metal-ceramic individual substrates will not be achieved.

[0012] In particular, the described method, in which the generation of local thermomechanical stress is combined with the generated predetermined breaking lines, proves to be advantageous because it enables automatic separation or division of the ceramic element. As a result, manual breaking or breaking caused by mechanical action on the ceramic element can be avoided. This reduces the likelihood of faulty breaking, as, for example, the probability or possibility of incorrect force application during breaking is eliminated. Furthermore, possible scratches that could be caused by the action during manual or mechanical breaking are avoided. Finally, it is also possible to avoid fingerprints or similar marks that could potentially be left on the metal-ceramic substrate, in particular on the at least one metal layer, during manual breaking.This is therefore a contactless process that can be carried out automatically and leads to the desired division of the metal-ceramic substrate into individual metal-ceramic substrates.

[0013] In particular, it is a metal-ceramic single substrate used as a circuit board, in which a metallization, i.e., a component metallization, is formed on the component side. Due to the structuring, this metallization has a plurality of electrically insulated metallization sections. These metallization sections form, for example, connection surfaces or pads or conductor tracks of the circuit board. The ceramic element preferably has Al2O3, Si3N4, AlN, an HPSX ceramic (i.e., a ceramic with an Al2O3 matrix comprising an x-percent ZrCh content, for example Al2O3 with 9% ZrCh = 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. In particular, it is a ceramic element with a thermal conductivity greater than 100 W / mK, preferably greater than 120 W / mK or particularly preferably greater than 130 W / mK.It is also conceivable that the ceramic element is 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.

[0014] Possible materials for component metallization and / or backside metallization include copper, aluminum, molybdenum, tungsten, 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. Preferably, the component metallization corresponds to the backside metallization in terms of its material or differs. Furthermore, it is preferably provided that the component metallization and / or backside metallization on the manufactured metal-ceramic substrate is surface-modified, in particular as component metallization. A possible surface modification could be, for example, sealing with a precious metal, in particular silver and / or gold, or (electroless) nickel or ENIG (“electroless nickel immersion gold”), or edge encapsulation of the metallization to suppress crack formation or crack widening.For example, the metal of the component metallization also differs from the metal of the backside metallization.

[0015] The bonding of the metal layer, i.e., the component metallization and / or the backside metallization, to the ceramic element can be achieved, for example, using a DCB process, an AMB process, diffusion bonding, in particular ADB, and / or hot isostatic pressing. A person skilled in the art understands a "DCB process" (Direct Copper Bond Technology) or a "DAB process" (Direct Aluminum Bond Technology) to be a process used, for example, to bond metal layers or sheets (e.g., copper sheets or foils, or aluminum sheets or foils) to one another and / or to ceramic or ceramic layers, specifically using metal or copper sheets or metal or copper foils that have a layer or coating (fusion layer) on their surface.In this process, described for example in US 3 744 120 A or in DE23 19 854 C2, this layer or coating (melting layer) forms a eutectic with a melting temperature below the melting temperature of the metal (e.g. copper), so that by placing the foil on the ceramic and by heating all the layers, these can be bonded to one another, by melting the metal or copper essentially only in the area of ​​the melting layer or oxide layer.

[0016] Preferably, the ceramic layer and the metal layer are bonded by means of a direct metal bonding process, a hot isostatic pressing process, a soldering process and / or a diffusion bonding process.

[0017] In particular, the DCB process then comprises the following process steps:

[0018] • Oxidizing a copper foil to form a uniform copper oxide layer;

[0019] • Placing the copper foil on the ceramic layer;

[0020] • Heating the composite to a process temperature between approximately 1025 to 1083°C, e.g. to approximately 1071°C;

[0021] • Cooling to room temperature. An active solder process, e.g. for joining metal layers or metal foils, in particular copper layers or copper foils to ceramic material, is a process that is also used specifically for producing metal-ceramic substrates. A bond is created between a metal foil, e.g. copper foil, and a ceramic substrate, e.g. aluminum nitride ceramic, at a temperature of between approximately 600-1000°C using a brazing alloy that, in addition to a main component such as copper, silver, and / or gold, also contains an active metal. This active metal, which is, for example, at least one element from the group consisting of Hf, Ti, Zr, Nb, and Ce, creates a bond between the solder and the ceramic through a chemical reaction, while the bond between the solder and the metal is a metallic brazing alloy.Alternatively, a thick-film process can also be used for connection.

[0022] Preferably, an ADB (active diffusion bonding) process is provided as the diffusion bonding process, which comprises, for example, the following steps:

[0023] - Providing a ceramic element and a metal layer,

[0024] - providing a gas-tight container enclosing the ceramic element, wherein the container is preferably formed from the metal layer or comprises the metal layer,

[0025] - Forming the metal-ceramic substrate by bonding the metal layer to the ceramic element by means of hot isostatic pressing, wherein, to form the metal-ceramic substrate, an active metal layer or a contact layer comprising an active metal is arranged at least in sections between the metal layer and the ceramic element to support the bonding of the metal layer to the ceramic element. The container is preferably formed as a metal container made of a metal layer and / or another metal layer. Alternatively, it is also conceivable to use a glass container.

[0026] In hot isostatic pressing, the bonding is performed by heating under pressure, preventing the metal layer of the metal container, in particular the subsequent metal layer of the metal-ceramic substrate, and any eutectic layer formed there, from entering the melting phase. Accordingly, lower temperatures are required for hot isostatic pressing than for a direct metal bonding process, particularly a DCB process.

[0027] Compared to the bonding of a metal layer to a ceramic layer using a solder material, which typically uses temperatures below the melting temperature of the at least one metal layer, the present procedure advantageously dispenses with the need for a solder base material, requiring only an active metal. The use of pressure during hot isostatic pressing also proves advantageous because it reduces air inclusions or cavities between the metal layer on the one hand and the ceramic element on the other. This reduces or even prevents the frequency of shrinkage cavities in the formed or manufactured metal-ceramic substrate. This has a beneficial effect on the quality of the bond between the metal layer of the metal container and the ceramic element.In addition, it is advantageously possible to simplify the “second etching” and avoid solder residues and silver migration.

[0028] The contact layer comprising the active metal layer comprises more than 15 wt.% active metal.

[0029] Hot isostatic pressing is known, for example, from EP 3 080 055 B1, to whose content with regard to hot isostatic pressing explicit reference is hereby made.

[0030] Prior to the formation of the predetermined breaking line, a structure is introduced into the at least one metal layer by removing material from the bonded at least one metal layer. According to a preferred embodiment of the present invention, the ablation of ceramic materials is carried out using light from a first laser source and / or the local heating of the ceramic element in the region of the predetermined breaking line is carried out using light from a second laser source. In this case, it is preferably provided that the first light source and the second light source differ from one another, in particular with regard to wavelength, intensity and / or operating mode, i.e. they can be pulsed or continuous (cw) radiation. Alternatively, it is conceivable that the first laser source and / or the second laser source are lasers of the same type, but which are operated, for example, at different wavelengths and / or intensities.For example, it is conceivable that the first and / or second laser source is a YAG, fiber or CO2 laser.

[0031] In particular, however, it is provided that the first light source is designed such that it leads to material removal on the ceramic element, in particular on the top side or outside of the ceramic element, while the second light source is configured or designed such that it only leads to heating without material removal. It is also conceivable that the second light source is selected such that it contributes at least to a small extent to material removal. For example, it is also conceivable that the first light source is used to at least partially create the predetermined breaking line and to heat or preheat the ceramic element. Furthermore, it is conceivable that the predetermined breaking line is created by means of a chemical or mechanical process.

[0032] The first laser source and / or second laser source is preferably a USP laser source that provides light pulses with a pulse duration of 0.1 to 800 ps, ​​preferably 1 to 500 ps, ​​particularly preferably 10 to 50 ps. It has proven particularly advantageous to use such pulses, particularly at processing speeds between 0.2 and 8 m / s, to produce predetermined breaking lines or predetermined breaking points that exhibit a particularly favorable ratio between molten ceramic and crack formation within the predetermined breaking lines, thereby ensuring particularly reliable and successful breaking along the predetermined breaking lines without causing damage to the separated metal-ceramic substrate during breaking.

[0033] Preferably, a cooling medium, in particular a gas stream, is directed onto the ceramic element for cooling and / or heating. For example, the gas stream or cooling medium is cooled for this purpose so that the cooled gas stream or cooling medium impinges on the metal-ceramic substrate. Preferably, the gas stream is oriented such that it runs at least partially parallel to the laser light of the second laser source and / or at an angle to the beam direction of the laser light of the second laser source. Furthermore, it is conceivable that the gas stream is specifically directed onto partial areas of the metal-ceramic substrate, for example by means of suitable nozzle elements, in order to carry out the heat treatment on the metal-ceramic substrate locally, particularly in the area of ​​the planned predetermined breaking lines.

[0034] Furthermore, it is preferably provided that the gas flow strikes the surface of the metal-ceramic substrate substantially perpendicularly and / or is inclined at an angle between 45 °C and 90 °C relative to the metal-ceramic substrate surface.

[0035] The metal-ceramic substrate is preferably positioned in a holding element, wherein the holding element is coolable and / or heatable. For example, the holding element comprises cooling channels and / or cooling elements, such as heating coils, which are integrated into the holding element. It is particularly preferably provided that the cooling elements and / or heating elements are arranged in regions which lie below the planned predetermined breaking lines in a direction running perpendicular to the main extension plane, in order to generate targeted, locally limited heating and / or cooling of the metal-ceramic substrate in the region of the planned predetermined breaking lines. For example, it is also conceivable that laser light from the second laser source leads to heating and the cooling elements in the holding element lead to cooling in the ceramic element. It is also conceivable that the holding element comprises a plurality of cooling elements or heating elements, which are preferably separately controllable.can be controlled separately. This makes it possible, for example, to ensure that the pattern lies below the intended breaking line, depending on the intended breaking line pattern. To do this, individual heating coils are switched on and others switched off. Alternatively, it is conceivable that the heating and / or cooling element is a channel system through which a cooling or heating fluid is optionally permeated.

[0036] Preferably, the ceramic element is cooled in a spatially limited manner. In particular, a cooling medium jet, for example, by means of a nozzle, is directed specifically at a limited surface area of ​​the ceramic element in order to cool it. For example, a gas, such as nitrogen and / or compressed air, is used as the cooling medium to specifically effect cooling in a specific area. It is also conceivable that dry ice is used to cool the ceramic element locally or globally.

[0037] The spatial limitation of the cooling process proves particularly advantageous because it also creates a targeted spacing of the cooling effect from the areas of the metal-ceramic substrate where a bond exists between the at least one metal layer and the ceramic element. This prevents any rapid temperature changes from influencing the bonding behavior between the at least one metal layer and the ceramic element. Otherwise, there could be a risk of the metal layer and the ceramic element separating from each other again.

[0038] It is preferably provided that the surface to be cooled or the cooled surface which is produced in the ceramic element or on the ceramic element maintains a minimum distance from the at least one metal layer which is greater than 50 pm, preferably greater than 25 pm and particularly preferably greater than 10 pm.

[0039] Preferably, the ceramic material is heated and cooled along a specific path, with less than 5 seconds, preferably less than 2.5 seconds, and particularly preferably less than 1 second, elapsing between heating and cooling. In particular, the surface to be cooled lags behind the surface just heated, in order to generate cooling as immediately after heating as possible. It is particularly advantageous to keep the time interval between heating and cooling as short as possible to prevent the heat generated from being redistributed during processing of the ceramic element with the light from the second laser source before the cooling effect is initiated in the same area. This allows thermomechanical stresses to be generated more effectively, which contribute to the separation of the ceramic element. Nevertheless, the cycle time for separation can be further increased.It is also conceivable that a process of heating and cooling is repeated, in particular cyclically heating and cooling is initiated in several overflows in order to finally cause a sufficiently high thermomechanical stress in the ceramic element, which leads to the separation of the ceramic element.

[0040] Preferably, an area cooled by the cooling medium is smaller than 2 mm 2 , preferably less than 0.6 mm 2 and particularly preferably less than 0.2 mm 2 .

[0041] Preferably, an area heated by the light is smaller than 0.25 mm 2 , preferably less than 0.06 mm 2 and particularly preferably less than 0.01 mm 2 .

[0042] Preferably, the removal of ceramic material takes place on a first side of the ceramic element and the heating of the ceramic element takes place on a second side opposite the first side, and / or the predetermined breaking line is interrupted or continuous. In the case of opposing processing, in particular when creating the predetermined breaking line on one side and generating the thermomechanical stress on the other side, it is advantageously possible to realize the predetermined breaking line and the separation process in the ceramic element as simultaneously or in parallel as possible. Alternatively, it is conceivable for the heating to take place on the same side as the creation of the predetermined breaking line. In this case, a common holding element can be used for creating the predetermined breaking line and the subsequent separation by combining heating and cooling of the ceramic element in a locally limited area.

[0043] Furthermore, the predetermined breaking line can be notched or V-shaped, for example, and / or modulated in depth along its direction, and even interrupted, for example. For example, the predetermined breaking line can be a perforation or, alternatively, a continuous notch pattern that defines the desired separation.

[0044] Furthermore, it is preferably provided that the generation of the predetermined breaking line and / or the heating or cooling takes place after structuring the metal-ceramic substrate, ie after the at least one metal layer has been structured in such a way that conductor tracks and / or connection surfaces have been generated on the component side.

[0045] Furthermore, it is preferably provided that the removal of ceramic material creates a predetermined breaking line with a depth of less than 50 pm, preferably less than 20 pm, and particularly preferably less than 15 pm. It has been found that shallow breaking lines are necessary or required, so that it is not necessary to create predetermined breaking lines as deep as those typically created to ensure a clean break.

[0046] This saves time in the manufacturing process when creating the predetermined breaking line. It also saves the energy required to create the predetermined breaking line.

[0047] Preferably, during cooling and / or heating, a maximum temperature change of more than 1 °C / s, preferably more than 10 °C / s, and particularly preferably more than 50 °C / s, is achieved. The correspondingly high temperature change allows the desired thermomechanical stresses to be specifically generated in the target area, which generate or cause the automatic fracture.

[0048] Preferably, the separation is performed without mechanical and / or manual intervention on the metal-ceramic substrate. This advantageously makes it possible to avoid damaging the metal-ceramic substrate, thereby protecting the separated metal-ceramic substrate, for example, from uncontrolled breakage and / or fingerprints.

[0049] Preferably, the metal-ceramic substrate is fixed, for example, by means of a vacuum, at least temporarily, preferably throughout the entire separation or division process. In this case, the person skilled in the art defines the entire division process as the process that begins with the creation of the predetermined breaking line and ends with the removal of the individual metal-ceramic substrates. Through appropriate fixation and the effect of the vacuum, additional tension can also be generated in the metal-ceramic substrate, which leads to the desired fracture or separation being automatically generated.

[0050] The present invention further relates to a system for carrying out a method according to the invention, as well as a metal-ceramic substrate produced using the method according to the invention. All properties and advantages described for the method apply analogously to the system or the metal-ceramic substrate, and vice versa.

[0051] In particular, it is provided that the system comprises a device for heating and cooling the metal-ceramic substrate. For example, this device provides a second laser source and a cooling medium source, which can achieve heating and cooling in a targeted area of ​​the ceramic element with a limited area. Preferably, a laser beam and / or a cooling medium beam used can be aligned, preferably aligned such that they are arranged directly adjacent to one another. This advantageously makes it possible, when this device moves below or above the ceramic element along the direction of the predetermined breaking line, to create the desired effect of short-term heating and short-term cooling, which ultimately causes the thermomechanical stresses that lead to the fracture of the ceramic element.

[0052] Further advantages and features will become apparent from the following description of preferred embodiments of the subject matter according to the invention with reference to the accompanying figures. Individual features of the individual embodiments can be combined with one another within the scope of the invention.

[0053] It shows:

[0054] Fig.1 schematic representation of a method for processing a metal-ceramic substrate according to a first exemplary embodiment of the present invention in a first sectional view and

[0055] Fig. 2: schematic representation of the method for processing a metal-ceramic substrate according to the first exemplary embodiment of the present invention in a second sectional view and

[0056] Fig. 3 schematic representation of a method for processing a metal-ceramic substrate according to a second exemplary embodiment of the present invention in the second sectional view

[0057] Figure 1 schematically shows a method for providing a metal-ceramic single substrate 1, which is separated from a metal-ceramic substrate 10 provided as a large card, according to a first preferred embodiment of the present invention. Such a metal-ceramic single substrate 1 preferably serves as a carrier for electronic or electrical components that can be bonded to the metal-ceramic single substrate 1. Essential components of such a metal-ceramic single substrate 1 are a ceramic element 20 extending along a main extension plane HSE and at least one metal layer 21 bonded to the ceramic element 20. The ceramic element 20 is made of at least one material comprising a ceramic.The at least one metal layer 21 and the ceramic element 20 are arranged one above the other along a stacking direction S running perpendicular to the main extension plane HSE and, in a manufactured state, are at least partially bonded to one another via a bonding surface. Preferably, the at least one metal layer 21 is then structured to form conductor tracks or connection points for the electrical components. For example, this structuring is etched into the at least one metal layer 21. However, a permanent bond, in particular a bonded bond, must be formed beforehand between the at least one metal layer 21 and the ceramic element 20.

[0058] In order to permanently bond the metal layer 21 to the ceramic element 21, a system for producing the metal-ceramic substrate 10, in particular using a DCB or DAB bonding process, comprises a furnace in which a stacked arrangement of the ceramic element 20 and the at least one metal layer 21 is heated, thus achieving the bond. For example, the at least one metal layer 21 is a metal layer 21 made of copper, wherein the at least one metal layer 21 and the ceramic element 20 are bonded to one another using a DCB (direct copper bonding) bonding process. Alternatively, the at least one metal layer 21 can be bonded to the ceramic element 20 using an active soldering process, an ADB (active diffusion bonding) process, hot isostatic pressing, or a thick-film process.

[0059] After bonding, in particular using a DCB process, a flash soldering process, an active diffusion bond, hot isostatic pressing, and / or a thick-film process, the metal-ceramic substrate 10 is structured and provided as a large card. Such large cards are to be singulated in the subsequent process in order to provide individual metal-ceramic substrates 1. For such singulation, it is preferably provided that the large card is processed using laser light from a first laser source, in particular using ultrashort pulse laser light (not shown here). In this case, it is possible to form a predetermined breaking line 7, along which the large card is broken in the subsequent process, forming the individual metal-ceramic substrates 1. Those skilled in the art understand an ultrashort pulse laser to be, in particular, laser sources that emit laser pulses whose pulse lengths are less than one nanosecond.Preferably, the pulse duration is between 0.1 and 100 ps. Furthermore, it is conceivable for the pulse duration to be in the femtosecond range, i.e., the pulse length is between 0.1 and 100 ps. Alternatively, the use of a CO2 laser is also conceivable. For example, the metal-ceramic substrate 1 is arranged in a holding element at least during the production of the predetermined breaking line, preferably during the entire cutting process.

[0060] In particular, it is provided that the metal-ceramic substrate 1 is arranged in a stationary manner by means of the holding element for producing the predetermined breaking line 7. In order to create a predetermined breaking line 7 in the metal-ceramic substrate 1, which in particular has a specific course across the metal-ceramic substrate 1, it is provided that laser light or a laser beam from the first laser source is moved across the metal-ceramic substrate 1. In other words: instead of moving the metal-ceramic substrate 1 relative to the laser light or its alignment, it is preferably provided that the alignment of the laser light or laser beam from the first laser source for forming the predetermined breaking line 7 is carried out in such a way that the laser light moved across the metal-ceramic substrate 1 creates a predetermined breaking line 7 at the respective points of impact.The laser light of the first laser source, which is moved across the metal-ceramic substrate 1, has a processing speed of between 0.1 and 2 m / s, and preferably between 0.8 and 1.5 m / s. Alternatively, it is conceivable that the metal-ceramic substrate 1 is displaced in order to change the position of the laser light 10 striking the metal-ceramic substrate 1. In particular, the first laser source is designed to remove material from the ceramic element 20, for example by appropriately adjusting the wavelength of the light and / or the light intensity. Alternatively, it is also conceivable that the predetermined breaking line 7 is produced by means of a mechanical or chemical process.

[0061] At the point in time shown in Figure 1 during the method for dividing or processing the metal-ceramic substrate, the predetermined breaking line 7 has already been created. The predetermined breaking line 7 shown in Figure 1 has a V-shaped or notch-shaped form in a sectional view that runs perpendicular to the main extension plane HSE and perpendicular to the direction of extension VR of the predetermined breaking line 7. Furthermore, the predetermined breaking line 7 has a depth T that is measured in particular along the stacking direction S. It is conceivable that the depth T in particular modulates or varies along the direction of extension VR, along which the predetermined breaking line 7 extends. For example, it is conceivable that a jagged or wave-shaped profile along the direction of extension VR is provided for a bottom of the predetermined breaking line 7.

[0062] In particular, a base of the predetermined breaking line 7, which is set back relative to the outer side of the ceramic element 20, takes on a linear shape and is height-modulated, in particular, along the direction VR. Height modulation is understood by those skilled in the art to mean a deviation from a depth T averaged along the direction VR of more than 10% of the average depth. If there are no deviations from the depth T that are greater than 10% of the average depth, the depth T is assumed to be essentially constant. For example, the depth T of the predetermined breaking line 7 can also be constant.

[0063] In order to enable the automation of the cutting of the metal-ceramic substrate 10 into individual metal-ceramic substrates 1, it is provided that the ceramic element 20 is specifically subjected to local thermomechanical stress in the region in which the predetermined breaking line 7 is formed. This is achieved, for example, by local heating in the region of the predetermined breaking line 7 followed by cooling, in particular quenching, of the ceramic element 20. This causes such thermomechanical stresses in the ceramic element 20 that a fracture occurs in the correspondingly treated region of the predetermined breaking line 7, in particular along the predetermined breaking line 7. The ceramic element 20 is specifically heated briefly in a spatially limited area and then cooled again.

[0064] It has been found that it is advantageous if a predetermined breaking line 7 already exists in order to prevent an uncontrolled break, which in particular does not run along the desired parting line. In other words: the predetermined breaking line 7 embedded in the ceramic element 20 specifies the direction along which the automated break occurs, which in turn is initiated by the process sequence in which the ceramic element 20 is first briefly heated locally and then cooled again. In the exemplary embodiment shown in Figure 1, the ceramic element 20 is heated in the region of the predetermined breaking point 7 using laser light 15 from a second laser source. In particular, it is provided that the second laser source is designed such that it can achieve a heat input or a heat increase in the ceramic element 20 in the irradiated area, but does not lead to the removal of material.For example, by selecting the appropriate wavelength and / or intensity, the desired heat input can be achieved without any material removal.

[0065] In the exemplary embodiment shown in Figure 1, the laser light 15 of the second laser source is directed onto the side of the ceramic element 20 opposite the predetermined breaking point 7. Alternatively, it is conceivable for the light 15 of the second laser source to be directed onto the same side of the ceramic element 20, in particular in the regions of the predetermined breaking line 7 into which the predetermined breaking line 7 is also embedded. Furthermore, it is preferably provided that the heating and / or cooling takes place in a locally limited sub-region of the ceramic element 20 in which the predetermined breaking line 7 is located and / or which is sufficiently spaced from the at least one metal layer 21 of the metal-ceramic substrate 10. For example, it is provided that a distance A between the light 15, in particular a laser beam, and the at least one metal layer 21 is at least 50 pm.This advantageously prevents the thermomechanical stress generated in the region of the predetermined breaking line 7 from impairing or even damaging the bond between the at least one metal layer 21 and the ceramic element 20 in the metal-ceramic substrate 10.

[0066] Furthermore, it is provided that a depth T of the predetermined breaking line 7 is reduced compared to those required to effect a purely manual division of the metal-ceramic substrate 10 into the individual metal-ceramic substrates 1. For example, the depth T or the average depth of the predetermined breaking line 7 is less than 130 pm, preferably less than 100 pm, and particularly preferably less than 70 pm.

[0067] In the side view or sectional view shown in Figure 2, the metal-ceramic substrate 10 is shown in a sectional plane that runs through the predetermined breaking line 7. In other words: the sectional plane runs along the direction VR of the predetermined breaking line 7. In the exemplary embodiment shown here, the predetermined breaking line 7 is jagged with a modulated depth T. In particular, the illustration in Figure 2 shows the procedure for generating the thermomechanical stress within the ceramic element 20, in that heating is initially carried out using the light 15 of the second laser source, while a cooling medium 16 immediately follows.

[0068] The cooling medium 16 is directed, for example, in gaseous and jet form onto the ceramic element 20 to ensure local cooling in the region where heating occurred by the light 15 of the second laser source. For example, the second laser source and a cooling medium source are integrated into a common heating and cooling device 12, which moves along the direction VR of the predetermined breaking line 7 in order to effect heating and cooling in a specific region of the ceramic element 20 in the shortest possible time. For example, the cooling medium source and the second laser source are arranged one behind the other in the direction VR.

[0069] Regardless of whether the cooling medium source and / or the second laser source are integrated into a common device 12, it is preferably provided that a cooling medium 16 directed at the ceramic element 20 follows the heating process by the laser light from the second laser source. In other words: the heating, in particular the locally or regionally limited heating, of the ceramic element 20 takes place by moving the laser light 15, in particular the laser beam, over the ceramic element 20 in a direction predetermined by the direction of travel VR of the predetermined breaking line 7. A cooling medium that is specifically directed locally at a spatially limited area of ​​the ceramic element 20 preferably precisely follows the areas that were previously heated with the laser light 15 from the second laser source.It is quite possible that the surface area heated by the laser light 15 of the second laser source is smaller or larger than the surface area cooled by the cooling medium 16.

[0070] For example, the cooling medium is a gas, such as nitrogen or air, which is directed, for example by means of a nozzle, in a targeted and focused manner onto the area that was shortly before heated by the light 15 from the second laser source. In other words: cooling with the cooling medium already begins 16 when the light 15 has not yet completed the heating process and is currently heating a point on the ceramic element 20. It is conceivable that the cooling medium 26 impinges on the outside of the ceramic element 20 at an angle and / or perpendicularly. In particular, with an oblique orientation of the cooling medium 16 and / or the light 15 from the second laser source, it is possible to arrange the surface areas that are currently being cooled or heated as close to one another as possible.

[0071] With simultaneous movement of the laser light 15 and the cooling medium 16, this can result in immediate cooling after heating by the light 15 of the second laser source. The resulting thermomechanical stresses in the ceramic element 20 cause, among other things, a fracture along the planned and already embedded predetermined breaking line 7 without further mechanical action, in particular without manual intervention. This eliminates the need for contact on the top and / or bottom of the metal-ceramic substrate 20, significantly reducing the likelihood of scratches or damage to the top and / or bottom of the metal-ceramic substrate 10. Preferably, the dust generated during the fracture, for example, is vacuumed away.

[0072] The automatic separation of the ceramic element 20 allows the cycle time to be reduced and the likelihood of random breakage due to uneven force application during manual breaking can be advantageously reduced. In particular, the automatically separated metal-ceramic substrates 10a are removed from the holding element, in particular, are removed automatically and packaged automatically. This eliminates the need for the individual metal-ceramic substrates 1 to be broken and packaged manually. This also prevents fingerprints that would otherwise be inadvertently created on the individual metal-ceramic substrate 1.

[0073] Figure 3 shows a method for processing the metal-ceramic substrate 10 according to a second exemplary embodiment in the second side view, which is also selected in Figure 2. Here, it can be seen that the predetermined breaking line 7 differs from that of Figure 2, in particular in that the predetermined breaking line 7 in Figure 3 has a substantially constant depth T and no jagged modulation of the depth T.

[0074] 1 metal-ceramic single substrate

[0075] 7 Predetermined breaking line

[0076] 10 Metal-ceramic substrate 12 Heating and cooling device

[0077] 15 light

[0078] 16 Cooling medium

[0079] 20 Ceramic element 21 Metal layer

[0080] T Depth

[0081] HSE main extension level

[0082] S Stacking direction

[0083] A Distance VR Direction

Claims

Claims 1 . A method for dividing a metal-ceramic substrate (10), in particular a metal-ceramic substrate (10) provided in the form of a metal-ceramic large card, wherein the metal-ceramic substrate (10) is preferably divided into individual metal-ceramic substrates (1), comprising: - Providing a metal-ceramic substrate (10), wherein the metal-ceramic substrate (10) comprises at least one metal layer (21) and one ceramic element (20), - forming a debit book line (7), in particular by removing ceramic material from the ceramic element (20), - local heating of the ceramic element (20) in the region of the predetermined breaking line (7), in particular by means of laser light (15), and - Cooling the heated area of the predetermined breaking line (7) to separate the ceramic element (20) along the predetermined breaking line (7).

2. Method according to claim 1, wherein a removal of ceramic material by means of laser light from a first laser source and / or the local heating of the ceramic element (20) in the region of the predetermined breaking line (7) is carried out by means of light (15) from a second laser source.

3. Method according to one of the preceding claims, wherein the ceramic element (20) is cooled in a spatially limited manner.

4. Method according to one of the preceding claims, wherein the ceramic material (20) is heated and cooled along a specific course, wherein there is a time interval of less than 5 seconds, preferably less than 2.5 seconds and particularly preferably less than 1 second between heating and cooling.

5. Method according to one of the preceding claims, wherein the removal of ceramic material on a first side of the ceramic element (20) and the heating of the ceramic element (20) is realized on a second side of the ceramic element (20) opposite the first side and / or wherein the predetermined breaking line (7) is interrupted or continuous.

6. Method according to one of the preceding claims, wherein the removal of ceramic material results in a predetermined breaking line (7) having a depth (T) or average depth which is less than 130 pm, preferably less than 100 pm and particularly preferably less than 70 pm.

7. The method according to any one of the preceding claims, wherein during cooling and / or heating a temperature change of more than 1 °C / s, preferably more than 10 °C / s and particularly preferably more than 50 °C / s is achieved.

8. Method according to one of the preceding claims, wherein the separation is carried out without mechanical and / or manual action on the metal-ceramic substrate (10).

9. Plant for carrying out a method according to one of the preceding claims.

10. Metal-ceramic single substrate (1) produced by a method according to one of the preceding claims 1 to 8.

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