Method for processing metal ceramic substrate

Abstract

To provide a method for processing a metal ceramic substrate.SOLUTION: A method for machining a metal ceramic substrate (1) includes the steps of: providing the metal ceramic substrate (1), the metal ceramic substrate (1) including one or more metal layers and a ceramic element which extend along a principal surface (HSE) and are vertically arranged along a lamination direction (S) which extends perpendicularly to the principal surface (HSE); and forming a recess (15), particularly a through-recess (15), in the metal ceramic substrate (1) by machining using a laser beam (10), particularly ultrashort pulse (USP) laser.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for processing a metal-ceramic substrate, an apparatus for such a method, and a metal-ceramic substrate produced by such a method. [Background technology]

[0002] Electronic modules, e.g. power electronic modules, are well known in the prior art. Such electronic modules typically use switchable or controllable electronic components that are interconnected via conductor tracks to a common metal-ceramic substrate. The essential components of the metal-ceramic substrate are an insulating layer, which in the case of a metal-ceramic substrate is made of a material that includes ceramic, and a metallization layer, which is preferably structured and formed on one component side of the metal-ceramic substrate to form conductor tracks.

[0003] Typically, the metal-ceramic substrate is realized as a large card which is separated into smaller metal-ceramic substrates before or after structuring. Such a large card is treated with laser light to generate predetermined break lines and / or separation lines. The respective metal-ceramic substrates can then be provided separately from the large card, for example by breaking the metal-ceramic substrate. The use of an ultrashort pulsed laser has been shown to be advantageous here, as described for example in US Pat. No. 5,999,336.

[0004] From DE 10 200 06 131 A method is known for treating a workpiece with laser light, the workpiece being placed on a stage. DE 10 200 06 13 200 A1 also relates to the production of drill holes by means of laser light. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 108950 [Patent Document 2] US Patent Application Publication No. 2016 / 207143 [Patent Document 3] European Patent Application Publication No. 0826457 Summary of the Invention [Problem to be solved by the invention]

[0006] Based on the prior art, the present invention aims to improve the processing of metal-ceramic substrates. [Means for solving the problem]

[0007] This object is achieved by a method for treating a metal-ceramic substrate according to claim 1, by an apparatus suitable for said method according to claim 9 and by a metal-ceramic substrate produced by such a method according to claim 10. Further embodiments are taken from the dependent claims and the description.

[0008] According to a first aspect of the invention, there is provided a method for treating a metal-ceramic substrate, comprising the steps of: providing a metal-ceramic substrate, the metal-ceramic substrate comprising one or more metal layers and a ceramic element arranged one above the other along a stacking direction extending along and perpendicular to a major surface of the substrate; forming recesses, in particular through recesses, in said metal-ceramic substrate by treatment with laser light, in particular with an ultrashort pulsed laser.

[0009] In contrast to the methods known from the prior art, a laser light (especially a UKP) laser is used to form the recesses. In this case, the skilled person will understand that the recesses are areas that are preferably surrounded or enclosed by more than 50%, preferably more than 75%, particularly preferably completely in one plane by the metal-ceramic substrate and that do not contain metal and / or ceramic. For example, the recesses are surrounded by a curved or polygonal contour generated by the laser light. In this case, it is envisaged that the recesses are used, for example, as through-hole plating and / or as areas for fastening elements such as screws and / or bolts to fasten the metal-ceramic substrate to a housing and / or another component after a suitable film and / or solder paste and / or other conductive material is introduced. The production with laser light has been shown to be advantageous, in particular in terms of quality and production time for forming the recesses. For example, by using ultrashort pulsed laser light, it is possible to reduce the number of post-processing steps for the metal-ceramic substrate. In addition to this, it is advantageously possible to guide, for example by corresponding mirror elements, to scan the laser light over the top surface of the metal-ceramic substrate so as to achieve the desired shape and contour of the recesses.

[0010] It is particularly preferred that the recess extends throughout the entire metal-ceramic substrate, i.e. from the top surface of the metal-ceramic substrate to the back side of the metal-ceramic substrate. The metal-ceramic substrate is preferably held or fixed by a support or holding element during treatment with the laser light.

[0011] Furthermore, the metal-ceramic substrate comprises one or more metal layers bonded to the upper surface of the ceramic layer. The metal and ceramic layers extend along the main surface and are arranged one above the other along a stacking direction extending perpendicularly to the main surface. Conceivable materials for the one or more metal layers are copper, aluminum, molybdenum and / or alloys thereof, as well as thin layers such as CuW, CuMo, CuAl, AlCu and / or CuCu, in particular a sandwich structure with a first copper layer and a second copper layer. The grain size of the first copper layer is different from that of the second copper layer. It is further preferred that the one or more metal layers are surface modified. Conceivable surface modifications are, for example, sealing with noble metals, in particular silver and / or gold, or ENIG (electroless nickel / substitutional gold plating), or edge sealing at the first or second metallization layer to inhibit crack formation or expansion.

[0012] For example, the ceramic element is one or more ceramic layers or a composite comprising one or more ceramic layers. Preferably, one or more of the ceramic layers comprises Al2O3, Si3N4, AlN, HPSX ceramics (i.e. ceramics with an Al2O3 matrix containing x percent ZrO2, e.g. Al2O3=HPS9 with 9% ZrO2 or Al2O3=HPS25 with 25% ZrO2), SiC, BeO, MgO, high density MgO (>90% theoretical density), TSZ (tetragonal stabilized zirconia), ZTA as material for ceramics. It is also envisaged that the insulating layer is designed as a composite or hybrid ceramic. Here, several ceramic layers, each differing in terms of their own material composition, are arranged one above the other and are joined together to form an insulating layer so as to combine various desired attributes. Preferably, ceramics that are as thermally conductive as possible are used for the lowest possible thermal resistance.

[0013] Ceramic element or layer is preferably understood to mean a material that is glass-free or consists of more than 50% glass. The ceramic element is therefore preferably a glass-free ceramic element. Preferably, the recess is produced by repeatedly traversing the metal-ceramic substrate along the same contour.

[0014] Preferably, the metal layer is bonded to the insulating layer by an AMB process and / or a DCB process. Those skilled in the art will understand that the "DCB process" (Direct Copper Bonding Technology) or "DAB process" (Direct Aluminum Bonding Technology) is a process that serves to bond metal layers or sheets (e.g. copper sheets or foils or aluminum sheets or foils) to each other and / or to ceramics or ceramic layers 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 Pat. No. 3,744,120 or DE 2,319,854, this layer or coating (fusion layer) forms a eutectic with a melting temperature below the melting temperature of the metal (e.g. copper). As a result, by placing a foil on the ceramic and by heating all layers, the ceramic and layers can be bonded to each other by melting the metal or copper only in the area of ​​the fusion or oxide layer.

[0015] In particular, the DCB process then comprises, for example, the following steps: oxidizing the copper foil so that a uniform copper oxide layer is formed; placing the copper foil on the ceramic layer; heating the composite to a processing temperature between about 1025 and 1083°C (for example up to 1071°C); cooling to room temperature. A process is envisaged which is also used in particular to produce metal-ceramic substrates by active soldering processes (for example for joining metal layers or foils, in particular copper layers or foils, with ceramic materials). The bond is produced at temperatures between about 650 and 1000° C. between a metal foil (for example copper foil) and a ceramic substrate (for example aluminium nitride ceramic) by means of a brazing alloy which, in addition to the main components such as copper, silver and / or gold, also contains an active metal. This active metal, for example one or more elements of the group Hf, Ti, Zr, Nb, Ce, establishes the connection between the brazing alloy and the ceramic by chemical reaction. The connection between the brazing alloy and the metal is, on the other hand, a metal brazing connection. Alternatively, thick film processes are also envisaged for the bond.

[0016] In a preferred embodiment, the laser light is directed towards the metal-ceramic substrate by one or more pivotable mirror elements or reflecting elements, in particular moved by one or more pivotable mirror elements or reflecting elements on the metal-ceramic substrate. By means of a corresponding scanning device, for example, it is possible to move the laser beam or laser light as precisely as possible at a position on the planned path of the future recess (i.e. the processing area). In this case, it is particularly envisaged that the one or more mirror elements are adapted to the pulse duration and / or wavelength of the laser light used so as to reduce losses during reflection at the one or more mirror elements. Furthermore, it is envisaged that the one or more mirror elements are concave and / or dielectric mirrors, so as to focus the laser beam at least partially already, preferably before or after passing through an additional lens. By focusing, in particular by a lens, the intensity of the incident laser pulse can be advantageously increased. Furthermore, it is particularly preferred that the one or more mirror elements can be pivoted around two or more axes. This can ensure that, by the respective orientation of the mirror elements, all points of the upper surface of the metal-ceramic substrate can be detected by the laser beam. Preferably with exactly one mirror element.

[0017] Preferably, the UKP laser is a laser source providing light pulses with pulse durations of 0.1-800 ps, ​​preferably 1-500 ps, ​​more preferably 10-50 ps. It has been found to be particularly advantageous to use such pulses with the abovementioned process speeds to generate recesses and / or predetermined break lines or predetermined break points with a particularly preferred ratio between molten ceramic and crack formation in the predetermined break line. This ensures, for example, a reliable or successful break in the case of a predetermined break line, in particular along the predetermined break line, without causing damage to the single metal-ceramic substrate during the break. Preferably, the predetermined break lines for the recesses are realized, for example, by the same laser system.

[0018] Preferably, the cross section of the recess extending parallel to the main surface is larger than the cross section of the laser light measured along the same surface. Preferably, the cross section of the recess has a first diameter and the cross section of the laser light has a second diameter, where the ratio of the second diameter to the first diameter is less than 0.2, preferably less than 0.1, more preferably less than 0.05. In this way, for example, by moving the laser light along the upper surface of the metal-ceramic substrate, it is possible to form a cutting contour that forms the shape of the subsequent cross section of the recess. In particular, such a process serves to form a recess in the subsequently manufactured metal-ceramic substrate through which a fastening device or fixture passes for fastening. Such a recess with a correspondingly larger cross section generally serves to form a through plating, but is preferably provided simply to fasten the metal-ceramic substrate to another component.

[0019] It is particularly preferred that the laser light is directed to the processing area of ​​the metal-ceramic substrate by a lens. The distance between the lens and the upper surface of the metal-ceramic substrate changes during processing. In particular, the distance between the lens and the upper surface of the metal-ceramic substrate refers to an area outside the area where recesses are formed, i.e. outside the processing area. By redrawing the distance between the lens and the upper surface of the metal-ceramic substrate, it is advantageously possible to take into account the fact that in the course of processing, ablation is performed on the metal-ceramic substrate, as a result of which the focus of the lens falls on an area where ablation of the metal-ceramic substrate material has already occurred, without a corresponding decrease in the distance between the lens and the upper surface of the metal-ceramic substrate. By a corresponding coordinate change of the distance between the lens and the upper surface of the metal-ceramic substrate, it can be advantageously ensured that the focus of the laser light is located directly above and / or directly below the area of ​​the metal-ceramic substrate material to be ablated or the boundary layer to be ablated. For this purpose, the distance between the lens and the metal-ceramic substrate is preferably changed along the stacking direction. In particular, the (total) change of the distance between the lens and the metal-ceramic substrate essentially corresponds to the thickness of the metal-ceramic substrate dimensioned in the stacking direction.

[0020] It is furthermore conceivable that the inclination of the laser light is changed during the process. This allows, for example, for the inner contour of the recess to have a desired shape. It is also conceivable that the recess is formed in such a way that a stepped contour is realized inside the recess. This allows, for example, for providing a free area on the upper surface of the metal-ceramic substrate in which the head of the fixture is a countersink. Here, it may be advantageous, for example, to provide a first section with a different inclination angle of the inner recess, such that this first section is adapted to the shape of the head of the fixture.

[0021] Preferably, the laser light is perpendicularly incident on the metal-ceramic substrate at least occasionally, and preferably during the entire process. This allows the production of cylindrical recesses with a substantially constant cross section in the stacking direction, for example with an inner inclination of the recess relative to the direction perpendicular to the main surface of less than 10%, preferably less than 5%, more preferably less than 2.5%.

[0022] Preferably, the metal-ceramic substrate is treated exclusively in the metal-free areas of the metal-ceramic substrate, e.g., recesses are intended to be created by repeatedly traversing the metal-ceramic substrate along the same contour.

[0023] For example, it is also envisaged that a further laser light is provided and that the recess is formed by the further laser light. This can significantly accelerate the creation of the recess. It is envisaged that the laser light and the further laser light simultaneously treat the metal-ceramic substrate at different points of the common contour. Both the laser light and the further laser light follow the common contour to form the recess.

[0024] Furthermore, it is preferred that focal lengths of the lenses exceed 300 mm are used. With relatively large focal lengths, in particular exceeding 300 mm, preferably exceeding 350 mm, more preferably exceeding 430 mm, it is advantageously possible to use the laser light to generate, in addition to the recesses, a predetermined break line with a relatively small inclination relative to the direction extending perpendicularly to the main surface. This advantageously ensures a uniform breaking behavior over the entire metal-ceramic substrate, in particular over large cards. Preferably, the same laser system is used to provide the laser light used to generate the predetermined break line on the one hand and to generate the recesses in the metal-ceramic substrate on the other hand. By changing the laser parameters and / or using filters, the characteristics for generating the predetermined break line on the one hand and the recesses on the other hand can preferably be changed.

[0025] In particular, the distance between the lens and the metal-ceramic substrate is never less than the focal length of the lens by a value greater than the thickness of the metal-ceramic substrate, especially when the lens and / or the metal-ceramic substrate are moved towards each other. This can ensure that the laser light always remains focused, especially when material is ablated layer by layer and the focus of the laser light is tracked.

[0026] Preferably, the distance changes continuously or stepwise. In particular, it is envisaged that the recess depth, in particular the current recess depth, is measured simultaneously with the processing of the metal-ceramic substrate to generate the recess, so that the distance between the lens and the metal-ceramic substrate can be set depending on the current value of the recess depth. For example, the recess depth is optionally measured by a camera and / or another laser system. Alternatively or additionally, it is envisaged that the laser light is moved along the closed contour with a stepwise change in the distance between the lens and the metal-ceramic substrate that occurs after each or a constant number of crossings of the closed contour.

[0027] Preferably, the metal-ceramic substrate comprises one or more backside metallizations. In particular, the one or more backside metallizations and the one or more metallizations are arranged on both sides of the ceramic element. By forming a recess that extends to the backside metallization and also ablates the backside metallization, it is advantageously possible to produce a recess in which the backside metallization is burr-free, in particular on the side of the backside metallization facing away from the ceramic layer. In this way, the method differs from conventional methods, in particular with a CO2 laser, in that a final post-processing step is omitted, in which the recesses are deburred. This accelerates the manufacturing process for producing a metal-ceramic substrate provided with recesses.

[0028] Preferably, the laser light is guided at least partially along a curved contour to form the recess. In particular, the curved contour corresponds to the direction of movement of the laser light guided, resulting in an at least partially annular or circular path for the edge of the recess. Alternatively, polygonal or angular or straight edge contours for the recess are envisaged, which are realised by corresponding adjustment of the direction of movement of the laser light (in particular by alignment of mirrors).

[0029] Furthermore, preferably, the separated components of the metal-ceramic substrate are removed, preferably by a vacuum mechanism. For example, a suction device, preferably integrated into the carrier and arranged under the area reserved for the processing area or recess, is provided for this purpose. When the laser light follows the corresponding contour that will be the boundary of the future recess, the area of ​​the metal-ceramic substrate surrounded by the boundary or the future boundary is cut. It is advantageously possible to fix the remaining or separated part of the metal-ceramic substrate to the carrier by a vacuum mechanism while the metal-ceramic substrate is released from the carrier, so as to enable or facilitate the separation of the cut area of ​​the metal-ceramic substrate from the remaining metal-ceramic substrate with the manufactured recess.

[0030] A further aspect of the invention is an apparatus for carrying out the process according to the invention. All features and advantages described for the method apply to the apparatus and vice versa.

[0031] A further aspect of the invention is a metal-ceramic substrate produced by the process according to the invention. All properties and advantages described for the method can be transferred to the metal-ceramic substrate as well, and all properties and advantages described for the metal-ceramic substrate can be transferred to the method as well.

[0032] Further advantages and features emerge from the following description of preferred embodiments of the subject matter according to the invention, with reference to the attached drawings, in which the individual features of the individual embodiments can thereby be combined with one another within the scope of the invention. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic diagram of a method for processing a metal-ceramic substrate according to a first exemplary embodiment of the present invention. [Diagram 2]FIG. 4 is a schematic diagram of a method for treating a metal-ceramic substrate according to a second exemplary embodiment of the present invention. [Diagram 3] FIG. 4 is a schematic diagram of a method for treating a metal-ceramic substrate according to a third exemplary embodiment of the present invention. [Figure 4] FIG. 5 is a schematic diagram of a method for treating a metal-ceramic substrate according to a fourth exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] FIG. 1 shows a schematic diagram of a method for processing a metal-ceramic substrate 1 according to a first preferred embodiment of the invention. Such a metal-ceramic substrate 1 preferably serves in each case as a carrier element for electronic or electrical components that can be connected to the metal-ceramic substrate 1. The essential components of such a metal-ceramic substrate 1 are a ceramic element 11 extending along the main surface HSE and one or more metal layers 21 bonded to the ceramic element 11. The ceramic element 11 is made of one or more materials, including ceramic. In this case, the one or more metal layers 21 and the ceramic element 11 are arranged one above the other along a stacking direction that extends perpendicularly to the main surface HSE and, in the manufactured state, are substantially bonded to one another at least in regions via bonding surfaces. The ceramic element 11 comprises one or more ceramic layers, and can also be formed from a plurality of ceramic layers, for example between which an intermediate metallization is formed or which forms a hybrid ceramic. Preferably, the one or more metal layers 21 are then patterned to form conductor paths or connection points for the electrical components. For example, this structuring is an etching into the one or more metal layers 21. However, beforehand a permanent bond (in particular a material bond) needs to be formed between the one or more metal layers 21 and the ceramic element 11 .

[0035] A system for manufacturing a metal ceramic substrate 1, in particular a DCB or DAB bonding process, to permanently bond one or more metal layers 21 to the ceramic element 11 comprises a furnace in which a laminated assembly of the ceramic element 11 and one or more metal layers 21 is heated to achieve bonding. For example, the one or more metal layers 21 are copper metal layers, and the one or more metal layers 21 and the ceramic element 11 are bonded together using a DCB (direct copper bonding) bonding method. Alternatively, the one or more metal layers 21 can be bonded to the ceramic element 11 by active soldering or thick film methods.

[0036] After bonding (in particular by a DCB process, an active soldering process and / or a thick film process), the metal-ceramic substrate is provided as a large card. Such large card is in each case singulated in a subsequent process to provide a singulated metal-ceramic substrate 1. Preferably, for such separation, it is intended to process the large card by a laser beam 10 (in particular by an ultrashort pulsed laser beam). Thereby, it is possible to immediately realize the separation by the laser beam 10 and / or to form a predetermined break line along which the large card is broken in a subsequent process to form a separated metal-ceramic substrate 1. By ultrashort pulsed laser, the skilled person understands in particular such a laser source which emits laser pulses with a pulse length of less than 1 nanosecond. Preferably, the pulse duration is between 0.1 and 100 ps. Furthermore, it is envisaged that the pulse duration is in the femtosecond range (i.e. 0.1 to 100 fs). In the exemplary embodiment shown in FIG. 1, the metal-ceramic substrate 1 is arranged on a carrier 40.

[0037] In particular, a laser light 10 (particularly a laser light 10 of a UKP laser) is used to generate a recess 15 (particularly a through recess 15) in the metal-ceramic substrate 1. The recess 15 is, for example, a kind of through hole used for example for through plating and / or a recess 15 provided as a through hole for providing a connection or fastening area where the metal-ceramic substrate 1 is coupled to a housing or another component as a power module. In this case, the recess 15 is generated temporarily before and after the predetermined break line. Preferably, the same laser light 10 (i.e. light from the same laser source) is used to generate the recess 15 and the predetermined break line. The intensity, pulse duration and / or power of the pulse for generating the predetermined break line are different from those for generating the recess 15.

[0038] Moreover, conveniently, the metal-ceramic substrate 1 is stationary and positioned by a carrier 40. The laser light 10 or laser beam is moved on the metal-ceramic substrate 1 so as to generate a predetermined break line and / or recess 15 in the metal-ceramic substrate 1 (particularly having a specific course as seen across the metal-ceramic substrate). In other words, instead of moving the metal-ceramic substrate 1 relative to the laser light 10 or the alignment position of the laser light 10, it is envisaged that the alignment position of the laser light 10 or laser beam is performed in such a way that the laser light 10 traversing the metal-ceramic substrate 1 generates a predetermined break line and / or recess 15 at each impact point. It is envisaged that the predetermined break line and / or recess 15 is continuous and / or interrupted, i.e. the predetermined break line appears as a perforation.

[0039] In order to align the laser light 10, in particular the laser light 10 is directed towards the mirror element 30. The laser beam 10 is reflected at the mirror element 30 and subsequently strikes the metal-ceramic substrate 1. In this case, in particular the mirror element 30 is pivotally mounted, in particular pivotally mounted about two or more axes, in order to align the laser light 10 to a specific processing area or to a specific area on the metal-ceramic substrate. Furthermore, preferably a lens 20 is arranged between the mirror element 30 and the metal-ceramic substrate 1. In particular the lens 20 extends along a plane substantially perpendicular to the direction of incidence of the laser light 10, over a length that corresponds approximately to the length and / or width of the metal-ceramic substrate 1, in particular as a large card. In other words, the laser light 10 traveling on the metal-ceramic substrate 1 always passes through the same lens 20, regardless of the processing area.

[0040] It has been shown to be particularly advantageous to use a lens 20 with a focal length of more than 300 mm, preferably more than 350 mm, more preferably more than 420 mm. Arranging the lens 20 at a distance A from the metal-ceramic substrate 1, which corresponds essentially to the focal length of the lens 20, makes it possible to generate a predetermined breaking point or a predetermined break line or recess 15 that is relatively slightly inclined with respect to the perpendicular to the main surface HSE of the metal-ceramic substrate 1. An angle of inclination of the predetermined break line or recess 15, which is otherwise essentially V-shaped or notch-shaped, has to be anticipated. This applies in particular to the predetermined break line or recess 15 that forms the edge of the metal-ceramic substrate 1. Such an inclined portion is thereby caused in particular by the fact that the laser light 10 or laser beam cannot strike the metal-ceramic substrate 1 perpendicularly uniformly over the entire surface of the metal-ceramic substrate 1. However, by using a focal length of more than 300 mm, this inclination (in particular in the edge region of the metal-ceramic substrate 1) is reduced such that the angle of inclination measured or referenced with respect to the perpendicular direction of the metal-ceramic substrate 1 is less than 10°, more preferably less than 10°. In particular, it is established that the deviation of the inclination angle compared to the predetermined fracture line orientation in the center of the metal-ceramic substrate 1 is not less than 12°. It is thus advantageously possible to produce fracture behaviors whose distribution is substantially homogeneous over the entire metal-ceramic substrate 1.

[0041] Moreover, the distance A between the lens 20 and the upper surface OS of the metal-ceramic substrate 1 is preferably varied, in particular reduced, during the process for producing the recesses 15. It is thus advantageously possible to track the focus of the laser light 10 caused by the lens 20 according to the depth of the recesses 15 already created during the processing of the metal-ceramic substrate 1. In other words, by varying the distance A, it is possible to take into account the successive ablation for forming the recesses 15, such that the focus of the laser light 10 shifts towards the metal-ceramic substrate 1 and / or to the back side of the metal-ceramic substrate as the ablation of the one or more metal layers 21 and / or ceramic elements 11 increases. In this way, the laser power is kept as large as possible in the area of ​​the material currently being ablated. As a result, a decrease in the laser efficiency for the ablation of the material is not to be expected with an increase in the ablation depth. This advantageously results in an accelerated ablation process, which accelerates the formation of the recesses 15. In particular, by varying the distance A, a shift of the focus along the stacking direction S is performed, in which the distance A between the lens 20 and the upper surface OS of the metal-ceramic substrate 1 is preferably varied continuously and / or continuously or stepwise. To vary the distance A, the lens 20 is preferably displaced along a direction perpendicular to the main surface HSE. Alternatively and / or additionally, it is envisaged that the carrier 40 and thus the metal-ceramic substrate 1 are displaced along a direction extending parallel to the stacking direction S so as to reduce the distance A between the lens 20 and the upper surface OS of the metal-ceramic substrate 1. In particular, the focal length of the lens 20 remains constant.

[0042] Fig. 2 shows a schematic representation of a method for producing a metal-ceramic substrate 1 according to a second exemplary embodiment of the invention. The method shown in Fig. 2 differs from the exemplary embodiment shown in Fig. 1 in that a suction device 25 is additionally provided. The suction device 25 is, for example, integrated in the carrier 40 and is arranged below the processing area where the planned recesses 15 are realized. By means of the suction device 25 it is advantageously possible to suck up the ablated particles of the metal-ceramic substrate 1 and / or to create a negative pressure that ensures that partial areas of the metal-ceramic substrate 1 that have separated during the processing of the metal-ceramic substrate 1 and / or during the formation of the recesses 15 can be separated from the metal-ceramic substrate 1 by the recesses 15. In particular, this concerns a process for forming a recess 15 whose cross section in a direction parallel to the main surface HSE is much larger than the cross section of the laser beam 10. In such a scenario, where the diameter and / or cross section of the laser beam 10 is smaller than the cross section of the recess 15, the laser beam 10 follows a movement along the processing direction B during processing that forms, for example, the contour of the recess 15 in a plane parallel to the main surface HSE. The partial area of ​​the metal-ceramic substrate 1 surrounded by the contour is then fixed to the carrier 40 by a vacuum mechanism as the remaining part, while the remaining finished part of the metal-ceramic substrate 1 is released from the carrier 40.

[0043] FIG. 3 shows a schematic representation of a method for generating recesses 15 in a metal-ceramic substrate 1 according to a third exemplary embodiment of the invention. In particular, FIG. 3 shows a top view of the metal-ceramic substrate 1 and a movement of the laser beam 10 along a movement direction B, forming an annular or arcuate profile. It is also envisaged that the laser beam 10 follows a spiral, in particular a profile with a decreasing and / or increasing radius. In particular, it is intended to realise an annular profile for the recesses 15 by a correspondingly selected processing direction B, in which, in a plane extending parallel to the main surface HSE, the recesses 15 have a first diameter D1 and the laser beam 10 has a second diameter D2. In this case, the ratio of the second diameter D2 to the first diameter D1 is less than 0.2, preferably less than 0.1, more preferably less than 0.05. As an alternative to an annular movement direction B, a polygonal movement direction B, a polygonal movement direction B and / or an at least partly linear movement direction B are also envisaged.

[0044] FIG. 4 shows a schematic representation of a method for processing a metal-ceramic substrate 1 according to a fourth preferred embodiment of the present invention. In particular, FIG. 4 shows a cross-section through the metal-ceramic substrate 1 along a section perpendicular to the main surface HSE. In this case, in particular during the processing of the laser light 10 (in particular for generating the through-hole or through-recess 15), the backside metallization 30 is also removed by the laser light 10 (in particular from an ultrashort pulsed laser). By using an ultrashort pulsed laser, it is advantageously possible to avoid the formation of burrs when generating the recesses 15, which are typically formed, for example, during manufacturing with a CO2 laser. Correspondingly, a post-processing step for deburring the formed burrs can thus be avoided. This represents an advantage in terms of time for producing a metal-ceramic substrate 10 with recesses 15. In particular, the recesses 15 are provided to receive fastening elements, such as for receiving bolts and / or screws that extend through the recesses 15, for example to a housing or another component, in order to fasten the metal-ceramic substrate 1. [Explanation of symbols]

[0045] 1 Metal-ceramic substrate 10 Laser light 11 Ceramic elements 15 Recess 20 Lenses 21 Metal layer 25 Suction Devices 30 Backside Metallization OS top HSE Main surface S Stacking direction S Processing direction D1 First diameter D2 Second diameter

Claims

1. A method for treating and fixing a metal-ceramic substrate (1), comprising the steps of: Providing a metal-ceramic substrate (1), the metal-ceramic substrate (1) comprising one or more metal layers (21) and one ceramic element (11), arranged one above the other along a stacking direction (S) extending along a main surface (HSE) and perpendicular to the main surface (HSE); forming through-holes (15) in the metal-ceramic substrate (1) by treatment with an ultrashort pulsed laser, the through-holes (15) serving as areas for engagement of fastening elements for fastening the metal-ceramic substrate (1) to a housing or another component, A method according to claim 1, wherein a cross-section of the through recess (15) extending parallel to the main surface (HSE) has a first diameter, a cross-section of the ultrashort pulsed laser measured along the same surface has a second diameter, and a ratio of the second diameter to the first diameter is less than 0.

2.

2. 2. The method of claim 1, wherein the ultrashort pulsed laser is directed to a processing area of ​​the metal-ceramic substrate (1) via a lens (20), and a distance (A) between the lens (20) and an upper surface (OS) of the metal-ceramic substrate (1) is changed during processing.

3. The method of claim 2 , wherein the focal length (L) of the lens is greater than 300 mm.

4. The method according to claim 3 , wherein the distance (A) varies continuously or in steps.

5. The method according to any one of the preceding claims, wherein the metal-ceramic substrate (1) comprises one or more backside metallizations (30).

6. The method according to any one of claims 1 to 5, wherein the ultrashort pulsed laser is guided at least partially along a curved contour to form the through recess (15).

7. The method according to any one of the preceding claims, wherein the separated components of the metal-ceramic substrate (1) are removed by a vacuum mechanism.

8. The method according to any one of the preceding claims, wherein the through recesses (15) are produced by repeatedly traversing the metal-ceramic substrate (1) along the same contour with the ultrashort pulsed laser.

9. The method according to any one of the preceding claims, wherein the ultrashort pulsed laser is perpendicularly incident on the top surface of the metal-ceramic substrate (1) during processing.

10. The method according to any one of claims 1 to 9, wherein a further laser light is provided, and the through recess (15) is formed by the ultrashort pulsed laser and the further laser light.

11. The method according to any one of the preceding claims, wherein the ceramic elements of the metal-ceramic substrate (1) are glass-free.

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