WO2022207601A1

WO2022207601A1 - Carrier substrate for electrical, more particularly electronic components, and method for producing a carrier substrate

Info

Publication number: WO2022207601A1
Application number: PCT/EP2022/058203
Authority: WO
Inventors: Stefan Britting; Andreas Meyer; Xinhe Tang
Original assignee: Rogers Germany Gmbh
Priority date: 2021-03-29
Filing date: 2022-03-29
Publication date: 2022-10-06
Also published as: CN117223401A; DE102021107872A1; EP4316217A1; KR20230151532A

Abstract

The invention relates to a carrier substrate (1), in particular a metal ceramic substrate, comprising an insulation layer (11) and a metal layer (12), wherein, in a primary direction (P) running parallel to the main extension plane (HSE), the metal layer (12) terminates, at least in some regions, in a flank profile (2), particularly an etched flank profile, wherein, when seen in the primary direction (P), the flank profile (2) extends from a first edge (15) on a top side (31) of the metal layer (12) facing away from the insulation layer (11) to a second edge (16) on a bottom side (32) of the metal layer (12) facing the insulation layer (11), characterised in that, when seen in the primary direction (P), the flank profile (2) has at least one first section (A1) having a straight extension and at least one second section (A2) with a curved extension.

Description

Carrier substrate for electrical, in particular electronic, components and method for producing a carrier substrate

The present invention relates to a carrier substrate for electrical, in particular electronic, components and a method for producing a carrier substrate.

Carrier substrates are well known, for example as printed circuit boards or circuit boards from the prior art, for example from DE 102013 104 739 A1, DE 19 927 046 B4 and DE 10 2009 033 029 A1. Typically, connection areas for electrical components and conductor tracks are arranged on one component side of the carrier substrate, it being possible for the electrical components and the conductor tracks to be interconnected to form electrical circuits. Essential components of the carrier substrates are an insulation layer, which is preferably made of a ceramic material, and a metal layer bonded to the insulation layer. Due to their comparatively high insulation strength, insulation layers made of ceramic have proven to be particularly advantageous. By structuring the metal layer, conductor tracks and/or connection areas for the electrical components can then be implemented.

Basically, in addition to a low thermal resistance, a high resistance to temperature changes is also desirable, which contributes to the longevity of the corresponding carrier substrate. In this context, it has proven advantageous, for example, to leave gaps in the edge area of the metal layer in order to reduce mechanical stresses and improve the breakage behavior of large cards. In particular, improving the breakage behavior of large maps is disclosed in document EP 1 061 783 A2. However, this generally leads to a reduction in the effective usable area for the connection of electrical or electronic components.

In order to improve the thermal shock resistance, it is known from DE 102018 123681 A1 to provide a flank profile with a local maximum and a local minimum. The profile of the flanks from EP 3474643 A1 provides at least two concave sections in the profile of the flanks.

Proceeding from this flinter ground, the present invention sets itself the task of further improving the carrier substrates known from the prior art, in particular with regard to their resistance to temperature changes and/or their effective size of the usable area.

This object is achieved by a carrier substrate according to claim 1 and a method according to claim 9. Further advantages and features of the invention result from the subclaims and the description and the attached figures.

According to the invention, a carrier substrate, in particular a metal-ceramic substrate, is provided, which comprises an insulation layer, preferably a ceramic layer, and a metal layer, the metal layer having a flank profile at least in regions in a primary direction running parallel to the main extension plane on the outermost circumference, in particular etched edge profile, which, viewed in the primary direction, extends from a first edge on a top side of the metal layer, which faces the insulation layer, to a second edge on a bottom side of the metal layer, which faces the insulation layer, and wherein the course of the flanks, seen in the primary direction, has at least a first section with a rectilinear course and at least a second section with a curved course. Compared to the carrier substrates known from the prior art, it is provided according to the invention that the profile of the flanks comprises a first section with a rectilinear course and a second section with a curved course. It has been found that such a flank profile not only enables the desired advantages in terms of thermal shock resistance, but is also operationally reliable and easy to produce. In particular, it is possible in a single etching step to realize a flank profile that implements a first section with a rectilinear course and a second section with a curved course. A straight course is understood to mean a course of the respective first section that can be described by a straight line or, taking into account manufacturing tolerances, by a curvature whose radius of curvature is greater than fifty times the thickness of the metal layer or a first thickness of the metal layer. For example, such a rectilinear course can be seen in a sectional image that extends perpendicularly to the flap extension plane.

The insulating layer preferably has Al2O3, S13N4, AlN, ZTA (zirconia toughened alumina), MgO, BeO, SiC or high-density MgO (>90% of the theoretical density), TSZ (tetragonally stabilized zirconium oxide) or ZTA as the material for the ceramic on. It is also conceivable for the insulation layer to be designed as a composite or flybrid ceramic, in which several insulation layers, each of which differs in terms of their material composition, are arranged one on top of the other and joined to form an insulation layer to combine various desired properties. It is even conceivable that the insulating layer, for example to form an IMB, is made of an organic material, for example a resin. Materials for the metal layer are copper, aluminum, molybdenum and/or their alloys and laminates such as CuW, CuMo, CuAl, AlCu and/or CuCu, in particular a copper sandwich structure with a first copper layer and a second copper layer, with a grain size in the first copper layer differs from the second copper layer. The course of the flanks is preferably produced by an etching step. Alternatively or additionally, it is conceivable that the profile of the flanks is produced by milling and/or laser ablation. In addition, it is preferably provided that the carrier substrate has at least one further metal layer and/or one further insulating layer in addition to the metal layer and the insulating layer. In this case, the carrier substrate is preferably put together in a sandwich construction and the insulating layer is arranged between the metal layer and the further metal layer. Provision is preferably made for the additional metal layer to be free of structuring. i.e. on the side of the ceramic layer opposite the metal layer, the further metal layer is designed to be continuous. In this case, the additional metal layer forms a rear-side metallization that allows, for example, a comparatively thin insulating layer of less than 800 μm to be used.

It is also conceivable that the second edge, seen along a circumferential direction (i.e. along a direction following the general course of the first edge and the second edge around the usable area), delimits the connection surface in the main plane of extension and in the circumferential direction has a meandering, stamp-shaped edge and/or has a sawtooth-shaped course, in particular the meandering, stamp edge-shaped and/or the sawtooth-shaped course extending over the entire second edge of the metal layer. It is also conceivable that the meandering, postage stamp edge-shaped and/or sawtooth profile of the metal layer extends only over a partial area of the second edge of the metal layer or that several partial areas adjoin one another at a distance from one another as seen in the circumferential direction. By forming a structured and/or modulated profile of the second edge, its surface enlargement is designed in such a way that mechanical stress can be distributed advantageously, essentially independently of the location where it occurs. The first edge is preferably modulated analogously. However, the course of the flanks in the circumferential direction can also have irregular returns, ie, for example, small and larger gaps that are mixed or arranged alternately with one another, or that are wavy, right-angled, parallelogram-shaped, or jagged. In particular, it is provided that the connection area does not extend over the entire length of the insulation layer along the primary direction. In other words: the insulating layer protrudes in the direction of the main plane of extension in relation to the metal layer, in particular in relation to the second edge. The metal layer is preferably structured and the first and second edges are created as a result of a structuring measure, e.g. B. etching or surface milling of isolation trenches. It is also conceivable that the metal layer has a material weakening in an edge region that extends at the first edge in the direction of a center of the metal layer or in the direction of the useful surface, ie inwards. Viewed in the primary direction, the edge region is therefore opposite to the course of the flank in relation to the first edge. A material weakening is to be understood in particular as meaning a variation or modulation in the metal layer thickness. For example, a dome-shaped recess on the upper side of the metal layer is to be understood as material weakening. A ratio of an extent of the edge region to a total length of the metal layer measured in the same direction is preferably less than 0.25, preferably less than 0.15 and particularly preferably less than 0.1. It is also conceivable that, viewed in the primary direction, a further edge region opposite the edge region is formed on the metal layer (the relationship described then takes into account the extent of the edge region and the further edge region). Provision is preferably made for the dimensioning of the edge area, ie in particular the ratio of the extent of the edge area viewed in the primary direction to the total length of the metal layer measured in the same direction, to depend on the first thickness of the metal layer. For example, for metal layers whose first thickness is greater than 150 μm - for example between 0.4 and 2.5 mm - the ratio of the extension of the edge region seen in the primary direction to the total length of the metal layer measured in the same direction is less than 0, 35, preferably less than 0.25 and more preferably less than 0.18. In this case, the extent or the total length is measured in particular in a direction oriented perpendicularly to the course of the first edge. In particular, the measurement begins of extension with the first edge and is directed towards a central area of the metal layer.

Furthermore, it is preferably provided that the second edge is covered circumferentially, in particular at least partially or completely, with a filling material. The filling material is suitable for suppressing the formation of cracks at the edge, i.e. inhibiting or even completely preventing the crack from expanding. Preferably, the filler material comprises a plastic material such as polyimide, polyamide, epoxy or polyetheretherketone. It is also conceivable that a ceramic portion is added to the plastic material. Examples of such an additive are silicon nitride, aluminum nitride, aluminum oxide, boron nitride or glass.

It is also conceivable that carbon fibers, glass fibers and/or nanofibers are added to the plastic material. Preferably it is envisaged that the filling material is heat resistant, i. H. the filling material does not melt at temperatures that occur when the carrier substrate is in position after the filling material has been applied and/or during soldering. Furthermore, it is preferably provided that the filling material is suitable for forming a firm and good bond with the insulation layer, preferably the chosen ceramic material, and the metal layer, preferably before the chosen metal, such as copper. Furthermore, it is provided that the thermal expansion coefficient of the filling material is equal to or greater than the thermal expansion coefficient of the insulation layer and/or that of the metal layer. For example, the coefficient of thermal expansion of the filler material is more than three times the coefficient of thermal expansion of the metal layer.

The edge profile preferably has a local maximum and at least one local minimum, ie a local maximum and a local minimum are arranged between the first edge and the second edge. For the purposes of the invention, the terms “maximum” and “minimum” mean the height or thickness of the metal layer at this point, based on the surface of the insulating layer facing the metal layer. In other words: a bulge is formed or bulging, for example in the form of a promontory or pre-elevation, in the course of the flank. It has been found to be advantageous that a flank profile that has at least one local maximum and one local minimum can significantly improve thermal shock resistance. In particular, the primary direction extends outwards, ie from an area provided by the metal layer as a usable area to a metal-free area on the carrier substrate. The improvement in the resistance to temperature changes due to the profile of the flanks with the local maximum and the local minimum also advantageously makes it possible to dispense with weakening the material, for example in the form of dome-shaped cavities, in the edge region, which increases the effective usable area on the upper side of the metal layer can. The course of the flanks is formed as the outside of the metal layer in a cross section running perpendicular to the plane of flap extension and parallel to the primary direction, or a corresponding sectional view. The number of local maxima and local minima is preferably less than 5 in each case. There is particularly preferably exactly one local maximum and one local minimum.

A turning point or a reversal point is preferably formed between the first edge and the second edge. The local maximum is preferably arranged between the reversal point or turning point and the second edge and the local minimum between the first edge and the reversing point or turning point. For example, the profile of the flanks can be described, at least in certain areas, using a polynomial of at least the third degree. It is conceivable that the course of the flanks along a circumference of the metal layer, ie along a closed curve within the Flaupter extension plane at the outermost circumference of the metal layer, more than 50%, preferably more than 75% and particularly preferably completely with a local maximum and a local minimum. A person skilled in the art understands a local maximum/minimum to be an area in which the edge profile in the vicinity is no larger/no smaller than in the local maximum/minimum. In this case, the flank progression in the form of global maxima or minima can certainly assume larger or smaller values than the local maximum or minimum. For example the slope progression assumes a global maximum at the first edge, while a global minimum is assumed at the second edge. Furthermore, it is preferably provided that the course of the edges extends continuously, ie essentially steplessly, along the primary direction.

It is preferably provided that the rectilinear course of the at least one first section is inclined by a second angle relative to the main extension plane, which is greater than 20°, preferably between 20° and 50° and particularly preferably between 25° and 40° . It has been found that such steep, straight curves are possible without adversely affecting the resistance to temperature changes or the production of the flank curve. At the same time, the comparatively steep rise creates an arrangement of the individual metal sections on the carrier substrate that is as economical and space-saving as possible.

Provision is preferably made for the curved area of the at least one second section to be concavely curved. It is preferably provided that only a single second section is provided or formed, in particular only a single concavely curved second section.

Furthermore, it is preferably provided that the at least one first section is arranged between the local maximum and the second edge. In particular, it is provided that only a single first section is arranged between the local maximum and the second edge and that preferably only a single first section and only a single second section are formed. In particular, the rectilinear course extends from the second edge to the local maximum, in particular the local maximum which is arranged closest to the second edge. In other words: the first section does not contain any curved partial area or is free of a curved partial area. It is conceivable that the first section comprises a number of rectilinear courses which, for example, are inclined at different angles. Furthermore, it is alternative and/or It is entirely conceivable that a plurality of curved areas are formed in the second section, which differ from one another in terms of their radius of curvature.

According to a preferred embodiment of the present invention, it is provided that the metal layer has a first thickness outside the flank profile, in particular in a central area provided as a useful area, and a second thickness in the local maximum, the second thickness being smaller than the first Thickness. This ensures that the local maximum does not protrude from the top of the metal layer. The local maximum extends like a bead in the circumferential direction and forms a precursor in the increase compared to the global maximum of the flank profile, namely the first edge.

A ratio of the second thickness to the first thickness is less than 0.55, preferably less than 0.5 and particularly preferably less than 0.45. It has been found that by setting the second thickness accordingly, it is possible to ensure that a rectilinear course is set in the first section, in particular between the local maximum and the second edge.

It is also conceivable that the local maximum is part of a plateau or a dome-shaped bulge. Seen in the circumferential direction (i.e. if one follows a direction of extension of the first edge or the second edge), the local maximum extends over more than 50% of the entire circumference of the metal layer, preferably over more than 75% of the metal layer, and particularly preferably completely along the perimeter of the metal layer. Furthermore, it is provided that the metal layer has the first thickness at the first edge and in particular represents the first thickness of a maximum thickness of the metal layer.

It is advantageously provided that the course of the flanks, measured in the primary direction, extends over a first length between the first edge and the second edge, with a ratio between the first length and the first thickness having a value between 0.5 and 2.5, preferably between 0.8 and 2.2, and especially preferably between 1.1 and 1.9. As a result, comparatively wide edge profiles can be implemented. For comparison: typically the ratio between the first length and the first thickness is less than 0.5. It has been found that this broadening of the edge profile not only has a positive effect on the thermal shock resistance, but also supports heat spreading, especially for components that are placed very close to the first edge, since this then also covers the area below the edge Flank course of the metal layer for heat transport can share. A broad edge progression also makes it possible to set the structuring with a local maximum and local minimum in a more controlled manner. Provision is preferably made for the second thickness to be measured at a point which, viewed in the primary direction, is 2/5 times the first length away from the second edge, in particular if the local maximum is not clearly evident from the course of the flanks.

It is preferably provided that the course of the flanks extends from the second edge on the underside to the local maximum over a second length, with a ratio between the second length and the first length having a value between 0.2 and 0.7, preferably between 0.25 and 0.6 and more preferably between 0.3 and 0.5. In other words: it has been shown that it is particularly advantageous if the local maximum, ie the local elevation in the course of the flank, seen from the second edge is in the first half or, preferably, in an area between the first half and the first third of the flank course is arranged. The local maximum is therefore in particular at the outermost edge of the metal layer and thus supports the thermal shock resistance of the entire carrier substrate.

It is preferably provided that an imaginary straight first connecting line, which runs through the first edge and the second edge, is inclined at a first angle relative to a connecting surface via which the metal layer is connected to the insulating layer, and wherein a first rectilinear second connecting line, which runs through the second edge and the local maximum, is inclined by a second angle relative to the connection surface, with a ratio of the second angle to the first angle being less than 0.8, preferred less than 0.7 and more preferably less than 0.6. This preferably applies to carrier substrates with a comparatively large first thickness, for example first thicknesses between 0.4 and 2.5 mm. In this embodiment, provision is made in particular for the local maximum to form in particular in a flat flank profile within the first third. It has already been found that with such a very flat flank profile in the first third (seen from the second edge) with a local maximum that is not significantly pronounced, significant improvements in thermal shock resistance can already be achieved. In addition, such a course can be covered comparatively easily with a filling material or with a casting material. For carrier substrates with a comparatively small first thickness, it is preferably provided that the second angle is larger than the first angle. For example, the ratio of the second angle to the first angle assumes a value between 0.5 and 2, preferably between 0.6 and 1.6 or particularly preferably between about 0.7 and 1.2. It is also conceivable that instead of the local maximum, a point on the outside of the edge course is taken that is 2/5 times the first length away from the second edge, seen in the primary direction.

It is preferably provided that the second angle is smaller than the first angle or the first angle is larger than the second angle. Such a ratio between the first angle and the second angle has been found to be particularly advantageous for carrier substrates with a comparatively large first thickness. In this case, the first thickness is preferably greater than 300 μm, preferably greater than 400 μm and particularly preferably greater than 500 μm or even greater than 1 mm. For example, the first thickness assumes a value between 300 μm and 5 mm, preferably between 400 μm and 3 mm and particularly preferably between 500 μm and 1 mm. The first thickness is particularly preferably greater than 1.3 mm and particularly preferably greater than 1.8 mm.

The ratio between the first angle and the second angle preferably changes along a circumferential direction running parallel to the main plane of extension; in particular, the ratio is modulated, for example periodically dish It is conceivable that the relationship between the first angle and the second angle reverses at least in sections, ie there are sections in which the first angle is larger than the second angle and sections in which the second angle is larger as the first angle.

In a preferred embodiment, it is provided that a ratio between the second thickness and the first length has a value between 0.08 and 0.4, preferably between 0.09 and 0.35, and particularly preferably between 0.1 and 0 .3 or even 0.2, especially when the second angle is smaller than the first angle. Especially for values between 0.1 and 0.3, there was a significant improvement in thermal shock resistance, which significantly extends the service life of the carrier substrate.

A further embodiment of the present invention provides that the metal layer has a third thickness in the local minimum, with a ratio of the third thickness to the second thickness having a value between 0.1 and 1, preferably between 0.3 and 0.95 and most preferably between 0.5 and 0.9. It has proven to be particularly advantageous if the local minimum has a significantly smaller thickness than the local maximum, after which, for example, the potting material or filling material can penetrate into these depressions in the area of the local minimum and thus, for example, result in an additional form fit seen in the primary direction. The ratio of the third thickness to the second thickness can change as seen in the circumferential direction. In particular, the ratio between the third thickness and the second thickness could be periodically modulated in the circumferential direction.

In a particularly preferred embodiment, it is provided that the metal layer has a first thickness of between 0.2 and 1 mm, preferably between 0.25 and 0.8 mm, and particularly preferably between 0.3 and 0.6 mm or between 0 4 and 2.5 mm, preferably between 0.5 and 2 mm, and particularly preferably between 0.6 and 1.5 mm's. It has turned out to be advantageous that the edge profile with the local maximum and the local minimum has an advantageous effect on the thermal shock resistance, both for the carrier substrates with a conventional first thickness and for a first thickness that is comparatively large. Preferably, the first thickness is greater than 1 mm, preferably greater than 1.5 mm, and most preferably greater than 2 mm. In particular for the carrier substrate with a comparatively large first thickness, it is provided that the insulating layer, ie in particular the ceramic layer, has a thickness that is less than 1.1 mm, preferably less than 0.8 mm, and is particularly preferred less than 0.6 mm. This also allows the temperature conductivity of the carrier substrate to be optimized.

It is preferably provided that the course of the flanks, viewed in the primary direction, extends over a first length which is less than 1000 μm and is preferably between 150 μm and 800 μm and particularly preferably between 300 μm and 600 μm. As a result, a comparatively narrow flank progression can be provided, which allows the metal sections to be arranged on the carrier substrate in a space-saving manner.

A further aspect of the present invention relates to a large card, which comprises a plurality of carrier substrates separated from one another by at least one predetermined breaking line, the predetermined breaking line extending adjacent and along the edge profile with the local maximum and the local minimum, in particular along its second edge. The individual carrier substrates are separated by breaking along the predetermined breaking line during the manufacturing process. Preferably, the predetermined breaking line runs along the course of the flanks of the further metal layer, ie that which lies opposite the metal layer in relation to the insulating layer in a stacking direction running perpendicularly to the main plane of extent. It has been found that the profile of the flanks according to the invention advantageously has a positive effect on the breakage behavior of the large card when the individual carrier substrates are separated. In particular, the probability of damage when separating the carrier substrates is reduced and the exclusion of unusable carrier substrates is thus reduced. It is particularly provided hen that the amount of metal per unit volume (specific fish amount of metal) compared to the central region of the metal layer with the flank course Usable area reduced to 20 to 70%, preferably to 20 to 65% and particularly preferably to 25 to 50%.

Preferably, the edge profile, in particular the second edge, for example of the further metal layer or the rear-side metallization, has a distance from the predetermined breaking line, measured in the primary direction, which is less than 1 mm, preferably a distance between 0.05 and 1 mm. A ratio of a distance, measured in the primary direction, between the second edge and the predetermined breaking line and the first length preferably has a value between 0.3 and 2.5, preferably between 0.4 and 2.0 and particularly preferably between 0.5 and 1 .5 on. This applies in particular to comparatively thick first thicknesses, e.g. H. first thicknesses between 0.4 and 2.5 mm. Provision is preferably made for the distance, measured in the primary direction, between the second edge and the predetermined breaking line to be smaller than the first length. Furthermore, it is provided that, for separating the individual carrier substrates, two groups of predetermined breaking lines are provided, which intersect and preferably run perpendicular to one another.

The carrier substrate is preferably embedded in an encapsulation, in particular together with a first electrical component. In particular, together with the curved etched edge profile, the carrier substrate can be particularly effectively embedded with the encapsulation and forms an effective positive connection or anchoring. This is particularly true for the etched edge runs where the second angle is greater than the first angle. In this case, the encapsulation is preferably solid, so that no cavities are formed between the encapsulation and the carrier substrate. As a result, a particularly compact electronic module can be realized with advantage, the carrier substrate of which is advantageously protected against impact.

Furthermore, it is preferably provided that a second electrical component is provided on the outside of the encapsulation, the first electrical component preferably being connected to the first electrical component via a through-contact running through the encapsulation. For example, it is provided that a via in the manufactured state has a contact produces a connection to an upper side of the first electrical component, ie a side which is opposite the carrier substrate in the stacking direction in the mounted state. Furthermore, it is preferably provided that a further metallization, in particular structured metallization, is provided on the outside of the encapsulation, which allows easy connection of the second electrical or electronic component.

It is preferably provided that a bonding layer is formed between the metal layer and the insulating layer in the manufactured carrier substrate, and wherein an adhesion promoter layer of the bonding layer has a sheet resistance that is greater than 5 ohms/sq, preferably greater than 10 ohms/sq and particularly preferably greater than 20 ohms/sq. Compared to the carrier substrates known from the prior art, it is provided that the surface resistance of an adhesion promoter layer of the bonding layer is greater than 5 ohms/sq, preferably greater than 10 ohms/sq and particularly preferably greater than 20 ohms/sq. The surface resistance determined is directly related to a proportion of the active metal in the adhesion promoter layer, which is decisive for the connection of the at least one metal layer to the insulating layer. The surface resistance increases with a decreasing proportion of active metal in the binding layer. A correspondingly high surface resistance thus corresponds to a low proportion of active metal in the adhesion promoter layer.

It has been found that the formation of brittle, intermetallic phases is promoted with an increasing proportion of active metal, which in turn is disadvantageous for the pull-off strength of the metal layer on the insulating layer.

In other words: With the sheet resistances according to the claims, those bonding layers are described whose pull-off strength is improved, ie increased, due to the reduced formation of brittle intermetallic phases. By specifically setting the surface resistances according to the claims, it is thus possible to achieve particularly strong connections between the at least one metal layer and the ceramic element. Such an increased bonding strength has an advantageous effect on the service life of the carrier substrate. There- In order to determine the surface resistance, it is provided that the metal layer and, if necessary, a solder base layer are first removed again from the finished carrier substrate, for example by etching. A surface resistance is then measured by means of a four-point measurement on the upper side or lower side of the carrier substrate freed from the at least one metal layer and the solder base layer. In particular, the surface resistance of a material sample is to be understood as its resistance based on a square surface area. It is customary to mark the surface resistance with the unit Ohm/sq(square). The physical unit of surface resistance is ohms.

It is preferably provided that a thickness of the bonding layer measured in the stacking direction, averaged over a number of measurement points within a predetermined area or in a number of areas that run or run parallel to the main extension plane, assumes a value of less than 0.20 mm preferably less than 10 pm and more preferably less than 6 pm. If several areas are mentioned, this means in particular that the at least one metal layer is divided into areas of the same size as possible and in each of these areas dividing the at least one metal layer at least one value, preferably several measured values, are recorded for the thickness. The thicknesses determined in this way at different points are arithmetically averaged.

Provision is preferably made for the bonding layer to be an adhesion-promoting layer comprising an active metal, and with the proportion of active metal in the adhesion-promoting layer comprising an active metal preferably being greater than 15% by weight, preferably greater than 20% by weight and particularly preferably greater than 25% by weight.

Provision is preferably made for the bonding layer and/or the further bonding layer to be an adhesion promoter layer comprising an active metal. In particular, provision is made for the bonding layer to be formed only from the adhesion promoter layer, which comprises the active metal. The adhesion promoter Layer in the bonding layer a compound with a component of Kerami kelements, such as nitrogen, oxygen or carbon, and the other components of the ceramic. Correspondingly, the adhesion promoter layer comprises, for example, titanium nitride, titanium oxide and/or titanium carbide. For example, the bonding layer comprises exclusively the adhesion promoter layer comprising the active metal, ie the bonding layer has no silver or other base solder components. In this case, it is provided that a thickness of the bonding layer measured in the stacking direction, averaged over a number of measurement points within an area that runs parallel to the main plane of extension, or the number of areas, assumes a value that is less than 0.003 mm (3000 nm), preferably less than 0.001 mm (1500 nm) and more preferably less than 0.0005 mm (500 nm) or even less than 0.00035 mm (350 nm). In particular for those bonding layers in which a solder base material and/or a silver portion is dispensed with, an even thinner bonding layer can be formed in a corresponding manner.

In particular, it is provided that the adhesion promoter layer comprising an active metal has an essentially constant thickness, in particular in contrast to the solder base layer, which is modulated because of an undulation in the insulation layer. In particular, the measured values of the thickness determined within the area or areas have a distribution to which a standard deviation of less than 0.2 μm, preferably less than 0.1 μm and particularly preferably less than 0.05 μm can be assigned . In particular, the physical and/or chemical vapor phase deposition of an active metal layer and the resulting bonding layer make it possible to achieve a homogeneous and evenly distributed thickness of the bonding layer, which in particular only consists of the adhesion promoter layer. The adhesion promoter layer can also have a constant thickness if it is formed in addition to the solder base material.

Another aspect of the present invention is supporting substrate, in particular

Metal-ceramic substrate comprising an insulating layer and a metal layer, wherein the metal layer in a primary direction running parallel to the main extension plane (HSE) ends at least in regions with a flank profile, in particular an etched flank profile, with the profile of the flanks, viewed in the primary direction, extending from a first edge on a top side of the metal layer, which faces away from the insulation layer, to to a second edge on an underside of the metal layer, which faces the insulating layer, characterized in that the flank profile, seen in the primary direction, has at least a first section with a convex curve and at least a second section with a concave curve. All the advantages and features described in connection with the carrier substrate, which has a straight first section, can be transferred analogously to the carrier substrate, which has a convexly curved second section.

In particular, it has been found that such a flank profile not only enables the desired advantages in terms of thermal shock resistance, but is also operationally reliable and easy to produce. In particular, it is possible in a single etching step to implement a flank profile that implements a first section with a rectilinear profile and a second section with a curved profile. It is preferably provided that the first section is formed directly adjacent to the second edge and the second section is formed directly adjacent to the first edge. It is conceivable that a third straight section is formed between the first section and the second section. For example, the course of the flank consists of the first section, the second section and the third section.

It is also conceivable that the linear third section is arranged directly adjacent to the second edge and/or between the first section and the second section.

Provision is preferably made for the convexly curved first section to have a first radius of curvature which is greater than 200 μm, preferably greater than 400 mίti and particularly preferably greater than 1000 gm and particularly preferably greater than 5000 gm, the concavely curved second section preferably having a second radius of curvature which is greater than the first radius of curvature. It is also conceivable that the first radius of curvature is greater than the second radius of curvature. A fourth length of the rectilinear third section is preferably smaller, preferably more than three times smaller, particularly preferably more than 5 times smaller or even more than 7.5 times smaller than the first radius of curvature and/or the second radius of curvature. In particular, it has been found that the adjusted ratio of the radii of curvature makes it possible to optimize the thermal shock resistance.

For example, the ratio of the first radius of curvature to the first radius of curvature assumes a value between 0.8 and 33, preferably between 2 and 33 and particularly preferably between 10 and 33. Furthermore, it is provided that the first radius of curvature and/or the second radius of curvature are smaller than the first thickness.

Furthermore, it is preferably provided if the first edge projects beyond the beginning of the flank profile, preferably the second section, at the first edge in the primary direction. In other words: the course of the edges is initially directed in the direction of the center of the metal layer and then curves in the direction of the second edge on the upper side of the ceramic element.

A further aspect of the invention relates to a method for producing a carrier substrate according to one of the preceding claims, wherein the profile of the flanks is preferably produced by an etching step, in particular a single etching step. All the features described for the carrier substrate and their advantages can be transferred analogously to the process and vice versa.

Furthermore, it is preferably provided that for etching a masking with a strip-shaped masking section above the subsequent edge running. It is possible to implement the desired edge profile in an operationally safe and reliable manner. The person skilled in the art will place and dimension the strip-shaped masking section in such a way that the edge course as claimed is established. The course of the strip-shaped masking section thus specifies the subsequent edge course of the structured metal section.

To connect metal and ceramic, the metal layer is preferably bonded to the insulating layer by means of an AMB process and/or a DCB process.

The person skilled in the art understands a “DCB method” (Direct Copper Bond Technology) or a “DAB method” (Direct Aluminum Bond Technology) to mean such a method which is used, for example, for connecting metal layers or sheets (e.g . B. copper sheets or foils or aluminum sheets or foils) together and/or with ceramics or ceramic layers, namely using metal or copper sheets or metal or copper foils which have a layer or coating ( Reflow layer), have. In this method, which is described for example in US Pat. No. 3,744,120 A or in DE23 19 854 C2, this layer or this 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 connected to one another, specifically by melting the metal or copper essentially only in the area of the melting layer or oxide layer.

In particular, the DCB method then z. B. the following process steps:

oxidizing a copper foil in such a way that a uniform copper oxide layer results; laying the copper foil on the ceramic layer;

• Heating the composite to a process temperature between about 1025 to 1083°C, e.g. B. to about 1071 ° C;

• Cool down to room temperature.

Under an active solder process z. B. for connecting metal layers or metal foils, in particular copper layers or copper foils with ceramic material, a method is to be understood, which is also used specifically for the production of metal-ceramic substrates, at a temperature between approx. 650-1000° C a connection between a metal foil, such as copper foil, and a ceramic substrate, such as aluminum nitride ceramic, produced un ter using a hard solder, which in addition to a Hauptkom component such as copper, silver and / or gold also contains an active metal. This active metal, which for example contains at least one element from the group Hf, Ti, Zr,

Nb, Ce is, makes a connection between the solder and the ceramic by chemical reaction, while the connection between the solder and the metal is a metallic brazing connection. Alternatively, a thick layer process is also conceivable for connection.

Provision is preferably made for the metal layer to be connected to the insulation layer by means of a DCB method or a DAB method. Surprisingly, it has been found that a particularly large improvement in terms of thermal shock resistance can be achieved if the metal layer is bonded to the insulating layer using a DCB method.

According to a further aspect of the present invention, a method for producing a carrier substrate, in particular a metal-ceramic substrate according to the invention, is provided, comprising:

- Providing at least one metal layer and one insulating layer, in particular a special ceramic element, a glass element, a glass ceramic element and/or a high-temperature-resistant plastic element, the at least one metal layer and the insulation layer extending along a main extension plane,

- arranging the at least one metal layer and the insulating layer in a stacking direction perpendicular to the main plane of extent, one above the other, an active metal layer being arranged between the at least one metal layer and the insulating layer, and

- Connecting the at least one metal layer to the insulation layer via the active metal layer, forming a bonding layer between the at least one metal layer and the insulation layer. All the advantages and properties described for the metal-ceramic substrate or the metal-ceramic substrates can be transferred analogously to the process and vice versa.

In particular, surface resistances that are greater than 5 ohms/sq, preferably greater than 10 ohms/sq and particularly preferably greater than 20 ohms/sq can be realized with the specified method. Finally, the method described makes it possible to realize such thin and homogeneously thick bonding layers that realize a technically sensible connection between the ceramic element and the metal layer and exhibit the said surface resistances.

In particular, the use of a separately executed active metal layer makes it possible to make this comparatively thin, whereby the comparatively thin thicknesses of the binding layer according to the claims can be realized, in particular averaged over various measured values within the specified area or areas. Examples of an active metal are titanium (Ti), zirconium (Zr), hafnium (Hf), chromium (Cr), niobium (Nb), cerium (Ce), tantalum (Ta), magnesium (Mg), lanthanum (La) and vanadium (V). It should be noted that the metals La, Ce, Ca and Mg can easily oxidize. It is also noted that the elements Cr, Mo and W are not classic active metals, but are suitable as a contact layer between S13N4 and the at least one metal layer or the solder system or solder material, since they can be combined with the at least one metal layer, for example copper. do not form any intermetallic phases and have no marginal solubility. Provision is preferably made for the proportion of active metal in the active metal layer to be greater than 15% by weight, preferably greater than 20% by weight and particularly preferably greater than 25% by weight.

Provision is preferably made for the proportion of non-metallic impurities in the arranged active metal layer to be less than 0.1% by weight, preferably less than 0.05% by weight and particularly preferably less than 0.01% by weight. By minimizing contamination, it is advantageously possible to make the layer thickness smaller, since in the event of contamination only part of the active metal present can contribute to the connection of the at least one metal layer to the insulating layer, while the rest of the active metal is bound by the contamination . By correspondingly ensuring a comparatively low proportion of impurities, a more effective connection is realized, which allows the proportion of active metal to be reduced, which in turn allows the bonding layer to be made thinner.

It is preferably provided that an active metal layer is used whose thickness is between 10 nm and 1000 nm, preferably between 50 nm and 750 nm, particularly preferably between 100 and 500 nm. Furthermore, it is preferably provided that the active metal by means of a physical and/or chemical vapor deposition on the insulation layer and/or the solder base material, which is preferably also designed as a foil, is applied. For example, it is also conceivable that the active metal is rolled down to the desired thickness together with the soldering material in order to form a comparatively thin bonding layer between the at least one metal layer and the insulating layer.

A solder foil is preferably used which is smaller than 20 μm, preferably smaller than 12 μm and particularly preferably smaller than 8 μm. For example, the thickness of the solder layer has a value between 2 and 20 pm or between consider 2 and 5 gm between preferably between 8 and 15 gm and more preferably between 5 and 10 gm. Furthermore, it is conceivable that the solder base material is provided as a film, as a paste, as a layer created by physical and/or chemical deposition, and/or as a layer formed by electroplating.

It is also conceivable that the connection via the active metal layer takes place as part of hot isotropic pressing. It is preferably provided that, during hot isostatic pressing of the metal containers in a heating and pressure device, a gas pressure of between 100 and 2000 bar, preferably between 150 and 1200 bar and particularly preferably between 300 and 1000 bar and a process temperature of 300° C. up to at least one metal layer is exposed to a melting temperature, in particular down to a temperature below the melting temperature. It has advantageously been found that it is possible in this way to bond a metal layer, i.e. a first and/or second metal layer of the metal container, to the ceramic element without the temperatures required for a direct metal bonding process, for example a DCB or a DAB -Process, and/or without a solder base material used in active soldering. In addition, the benefit or the use of a corresponding gas pressure allows the possibility of cavities free as possible, d. H. to produce a metal-ceramic substrate without gas inclusions between the metal layer and the ceramic element. In particular, process parameters are used that are mentioned in DE 2013 113734 A1 and to which explicit reference is hereby made.

Furthermore, it is preferably provided that the at least one metal layer and/or the at least one further metal layer is bonded to the insulation layer by means of an active soldering process and/or hot isostatic pressing and/or a DCB process. For example, it is provided that a method for producing a metal-ceramic substrate is provided, comprising:

- providing a soldering layer, in particular in the form of at least one soldering foil or brazing foil, - coating the insulation layer and/or the at least one metal layer and/or the at least one soldering layer with at least one active metal layer,

- arranging the at least one soldering layer between the insulation layer and the at least one metal layer along a stacking direction to form a soldering system which comprises the at least one soldering layer and the at least one active metal layer, wherein a soldering material of the at least one soldering layer is preferably free of a material that lowers the melting point or of is a phosphorus-free material, and

- Binding the at least one metal layer to the at least one ceramic layer via the soldering system by means of an active soldering process.

In particular, a multilayer soldering system consisting of at least one soldering layer, preferably free of elements that lower the melting point, particularly preferably a phosphorus-free soldering layer, and at least one active metal layer is provided. The separation of the at least one active metal layer and the at least one soldering layer proves to be advantageous in particular because comparatively thin soldering layers can be realized as a result, especially when the soldering layer is a foil. Otherwise, for soldering materials containing active metal, comparatively large solder layer thicknesses must be realized because of the brittle intermetallic phases or the high modulus of elasticity and high yield point of the common active metals and their intermetallic phases, which hinder the forming of the solder paste or solder layer, which means the minimum layer thickness is limited by the manufacturing properties of the solder material containing active metal. Correspondingly, for solder layers containing active metal, it is not the minimum thickness required for the joining process that determines the minimum solder layer thickness of the solder layer, but rather the minimum layer thickness of the solder layer that is technically feasible determines the minimum solder layer thickness of the solder layer. As a result, this thicker solder layer containing active metal is more expensive than thin layers. The person skilled in the art understands by phosphorus-free in particular that the proportion of phosphorus in the soldering layer is less than 150 ppm, less than 100 ppm and particularly preferably less than 50 ppm. In the context of the invention, the expression essentially means deviations from the exact value in each case by +/-15%, preferably by +/-10% and particularly preferably by +/-5% and/or deviations in the form of insignificant for the function changes.

Further advantages and features emerge from the following description of preferred embodiments of the subject according to the invention with reference to the attached figures. Individual features of the individual embodiments can be combined with one another within the scope of the invention.

It shows:

1: schematic representation of a carrier substrate according to a first preferred embodiment of the present inventions,

Fig. 2 schematic representation of a carrier substrate according to a second preferred embodiment of the present inventions

3 shows a schematic representation of a carrier substrate according to a third preferred embodiment of the present invention and

4 schematic representation of a carrier substrate according to a fourth preferred embodiment of the present invention.

FIG. 1 shows a carrier substrate 1 according to a first preferred embodiment of the present invention. Such carrier substrates 1 preferably serve as carriers for electronic or electrical components that can be connected to the carrier substrate 1 . Essential components of such a carrier substrate 1 are an insulation layer 11 extending along a Flaupter extension plane FISE and a metal layer 12 bonded to the insulation layer 11. The insulation layer 11 consists of at least one ceramic comprehensive material produced. The metal layer 12 and the insulation layer 11 are arranged one above the other along a stacking direction S running perpendicularly to the main extension plane HSE and are connected to one another in a materially bonded manner via a connection surface 25 . In the finished state, the metal layer 12 is structured to form conductor tracks or connection points for the electrical components. For example, this structure is etched into the metal layer 12 . In advance, however, a permanent bond, in particular a materially bonded connection, must be formed between the metal layer 12 and the insulating layer 11 .

In order to permanently bond the metal layer 12 to the insulation layer 11, a system for producing the carrier substrate, in particular in an SFB (super flat bonding) bonding method, includes, for example, an oven in which a pre-composite made of metal and ceramic is heated and so the binding is achieved. For example, the metal layer 12 is a metal layer 12 made of copper, the metal layer 12 and the insulating layer 11 being connected to one another in a materially bonded manner by means of a DCB (direct copper bonding) connection method. Alternatively, the metal layer 12 can be connected to the ceramic layer 11 via an active soldering process.

In particular, the metal layer 12 has a top side 31 facing away from the ceramic layer 11 and a bottom side 32 facing the ceramic layer 11 . The upper side 31 of the metal layer 12 comprises a useful surface 17 on which electrical or electronic components in particular can be mounted. The upper side 31 is delimited by a first edge 15 in a direction running parallel to the main extension plane HSE, while the lower side 32 of the metal layer 12 is bonded to the ceramic layer 11 via the connection surface 25 . The connection surface 25 is delimited outwards by a second edge 16 in a direction running parallel to the main extension plane HSE. The first edge 15 and the second edge 16 do not lie congruently one on top of the other, seen in a stacking direction S running perpendicular to the main plane of extension HSE, but are along a primary direction P offset to each other. The primary direction P runs in particular from a central area of the metal layer 12, in which the usable area 17 is provided, for example, outwards to an area of the carrier substrate 1 that is metal-free, ie an area in which the ceramic layer essentially covers the outside of the carrier substrate 1 forms. The first edge 15 is connected to the second edge 16 by a flank profile 2 extending along the primary direction P. For example, the flank course 2 is produced by an etching process, in particular by a single etching step. The course of the flanks 2 forms the outside of the metal layer 12 in the region between the first edge 15 and the second edge 16, in particular in a cross section running perpendicular to the flap extension plane FISE.

In order to improve the thermal shock resistance, provision is made for the flank profile 2 to have at least one local maximum 21 and at least one local minimum 22 between the first edge 15 and the second edge 16 . Viewed in the primary direction P, the local minimum 22 is preferably between the first edge 15 and the local maximum 21.

In particular, it has been found that it is advantageous for the thermal shock resistance if the flank profile 2 has at least one first section A1 with a straight profile and at least one second section A2 with a curved profile. In the exemplary embodiment shown in FIG. 1, exactly one first section A1 and exactly one second section A2 are formed. The first section A1 is directly adjacent to the second section A2. The first section A1 preferably extends in a straight line between the second edge 16 and the local maximum 21.

In particular, it is provided that the metal layer 12 has a first thickness D1 in the central area, ie in particular in the area of the effective surface 17, and a second thickness D2 in the local maximum 21, the first thickness D1 being greater than the second thickness D2 . Preferably, a ratio of the second di- Attach D2 to the first thickness D1 a value that is less than 0.55, preferably less than 0.45 and particularly preferably less than 0.35. In other words: the course of the flanks 2 has an additional bulge or elevation, for example in the form of a hill or bulge-like elevation.

Provision is also made for the flank course 2 to extend over a first length L1 measured in the primary direction P, with a ratio between the first length L1 and the first thickness D1 being between 0.5 and 2.5, preferably between 0.8 and 2.2 and particularly preferably between 1.1 and 1.9.

It is particularly preferred if the metal layer 12 has a third thickness D3 in the local minimum 22, with a ratio of the third thickness D3 to the second thickness D2 having a value between 0.1 and 1, preferably between 0.3 and 0.95 more preferably between 0.5 and 0.9. FIG. 1 also shows an imaginary straight first connecting line V1 and an imaginary straight second connecting line V2. The second connecting line V2 runs along the straight course of the first section A1. The first connecting line V1 runs through the first edge 15 and the second edge 16 and is inclined by a first angle W1 with respect to the connection surface 25 , while the second connecting line V2 runs through the second edge 16 and the local maximum 21 . In this case, the second connecting line V2 is inclined by a second angle W2 relative to the connecting surface 25 . It is preferably provided that the second angle W2 is larger than the first angle W1. For example, the ratio of the second angle W2 to the first angle W1 assumes a value between 0.5 and 2, preferably between 0.6 and 1.6 or particularly preferably about 0.7 and 1.2. In particular, the second angle W2 assumes a value that is greater than 20° or preferably between 20° and 50° and particularly preferably between 25° and 40°.

Provision is also made for the flank profile 2 to extend over a second length L2 from the second edge 16 on the underside 32 to the local maximum 21, with a ratio between the second length L2 and the first length L1 assumes a value between 0.2 and 0.7, preferably between 0.25 and 0.6, and more preferably between 0.3 and 0.5. It is preferably provided that a ratio between the second thickness D2 and the first length L1 has a value between 0.05 and 0.5, preferably between 0.08 and 0.4 and particularly preferably between 0.1 and 0.3 or even assumes 0.23.

It is also provided that the first section A1 extends over the second length L2, measured in the primary direction P, and the second section A2 over a fourth length L4, with a ratio of the fourth length L4 to the second length L2 having a value between 0.25 and 0.75, preferably between 0.4 and 0.6 and most preferably between 0.45 and 0.55.

In the exemplary embodiment shown in FIG. 1, the first thickness D1 is also between 0.2 and 1 mm thick, preferably between 0.25 and 0.8 mm, and particularly preferably between 0.3 and 0.6 mm.

FIG. 2 shows a carrier substrate 1 according to a second preferred embodiment of the present invention. The embodiment essentially corresponds to that from FIG. 1 and differs only in that the first thickness D1 has a value between 0.4 and 2.5 mm, preferably between 0.5 and 2 mm, and particularly preferably between 0 6 and 1.5 mm. In other words: compared to the embodiment from FIG. 1, this is a comparatively thick metal layer 12 in the central area. A ratio of the second thickness D2 to the first thickness D1 preferably assumes a value between 0.01 and 0.5, preferably between 0.05 and 0.4, and particularly preferably between 0.07 and 0.3. It is preferably provided that a ratio of the second angle W2 to the first angle W1 is less than 0.8, preferably less than 0.7, and particularly preferably less than 0.6.

A carrier substrate 1 according to a fourth preferred embodiment of the present invention is shown schematically in FIG. The metal layer 12 has in the respective local maxima 21 and local minima 22 each have the same thickness. However, it is also conceivable for the metal layer 12 to have different thicknesses in the different local maxima 21 and/or local minima 22 . In particular, the embodiment from FIG. 3 has a plurality of second sections A2 between the local maximum 21 and the first edge 15 .

FIG. 4 shows a carrier substrate 1 according to a third preferred embodiment of the present invention. In particular, the embodiment in FIG. 4 is characterized in that instead of a straight course in the first section A1, a convexly curved first section A1 is embossed. Thus, seen in the primary direction P, the flank profile comprises at least one first section A1 with a convexly curved profile and at least one second section A2 with a concavely curved profile. The first section A1 is preferably arranged directly adjacent to the second edge 16 and in particular the second section A2 is arranged directly adjacent to the first edge 15 . A third section running in a straight line can be formed between the first section A1 and the second section A2. In an exemplary embodiment, the course of the edges consists of the first section A1, the second section A2 and the third section A3.

Furthermore, it is provided that the convex profile in the first section A1 has a first radius of curvature R1 and/or the concave profile in the second section A2 has a second radius of curvature R2. It is preferably provided that the first radius of curvature R1 is greater than 200 μm, preferably greater than 400 μm and particularly preferably greater than 1000 μm and/or even greater than 5000 μm. Furthermore, it is provided that the second radius of curvature R2 assumes a value between 100 μm and 1000 μm, preferably a value between 150 and 700 μm and particularly preferably a value between 180 and 500 μm. It is particularly preferably provided that a ratio of the first radius of curvature R1 to the second radius of curvature R2 assumes a value that is greater than 0.8, preferably greater than 2 and particularly preferably greater than 0.6 or 10.

In other words: the first radius of curvature R1 is larger than the second radius of curvature R2, in particular at least one and a half times larger. For example, the ratio of the first radius of curvature to the first radius of curvature has a value between 0.8 and 33, preferably between 2 and 33 and particularly preferably between 10 and 33 on. Furthermore, it is particularly provided that the corresponding ratio of the first and/or second radius of curvature is formed when the first thickness D1 of the metal layer 12 is greater than 300 μm, preferably greater than 400 μm and particularly preferably greater than 500 μm. However, it is also conceivable that the first thickness D1 is less than 300 μm.

Furthermore, it is conceivable that the third section A3, which shows a rectilinear course, is arranged between the first section A1 with the convexly curved course and the second section A2 with the concave course. The rectilinear course preferably extends over a fourth length L4, which assumes a value that is less than 250 μm, preferably less than 150 μm and particularly preferably less than 100 μm. Furthermore, it is preferably provided that the insulation layer 11 or ceramic element has a thickness D that is smaller than the first thickness D1 of the metal layer 12.

Furthermore, it is preferably provided that the first edge 15, seen in the primary direction P, protrudes at least in relation to the adjoining partial area of the second section A2. This creates a kind of overhang over the concave second section and the course of the edges in the second section A2 hollows or dents the metal layer 12 a little. Furthermore, it is preferably provided that the course of the flanks extends from the first edge 15 to the second edge 16 along a primary direction P running parallel to the main extension plane HSE over a distance that is greater than 0.5 mm. It is preferably provided that a ratio of the first length L1 to the first thickness D1 is greater than 0.5, preferably greater than 0.65 and particularly preferably greater than 0.8. Furthermore, it is conceivable that the ratio of the first length L1 to the first thickness D1 is less than 2.5, preferably less than 2.2 and particularly preferably less than 1.8. The course of the flanks along the primary direction P is preferably shorter than 2.5 mm, preferably shorter than 2.2 mm and particularly preferably shorter than 1.8 mm. This information, in particular with regard to the length of the flank progression and with regard to the second radius of curvature R2, preferably also applies to the embodiment in FIGS. Section D1 formed immediately adjacent to the second edge 16 is provided. Reference list:

1 carrier substrate

2 edge progression

8 predetermined breaking point 11 insulation layer

12 metal layer

15 first edge

16 second edge 17 usable area 21 local maximum

22 local minimum 25 interface 31 top 32 bottom

100 big card

D thickness

D1 first thickness D2 second thickness

D3 third thickness

V1 first connecting line

V2 second connecting line L1 first length L2 second length

L3 third length

L4 fourth length

W1 first angle

W2 second angle S stacking direction

HSE main extension plane P primary direction

R1 first radius of curvature R2 second radius of curvature A distance

A1 first section

A2 second section A3 third section

Claims

Expectations

1. Carrier substrate (1), in particular metal-ceramic substrate, comprising an insulation layer (11) and a metal layer (12), the metal layer (12) in a primary direction (P) running parallel to the main plane of extension (HSE) at least in regions having a Flank profile (2), in particular etched flank profile, ends, with the flank profile (2) starting from a first edge (15) on a top side (31) of the metal layer (12), which faces away from the insulating layer (11), as seen in the primary direction (P). extends up to a second edge (16) on an underside (32) of the metal layer (12), which faces the insulating layer (11), characterized in that the flank profile (2) viewed in the primary direction (P) is at least has a first section (A1) with a rectilinear course and at least one second section (A2) with a curved course.

2. Carrier substrate (1) according to claim 1, wherein the flank profile (2) has at least one local maximum (21) and at least one local minimum (22).

3. Carrier substrate (1) according to one of the preceding claims, wherein the rectilinear course of the first section (A1) is inclined relative to the main extension plane (HSE) by a second angle (W2) which is greater than 20°, preferably between 20° and 50° and more preferably between 25° and 40°.

4. Carrier substrate (1) according to any one of the preceding claims, wherein the curved region of the at least one second section (A2) is concavely curved.

5. carrier substrate (1) according to any one of the preceding claims, wherein the at least one first section (A1) between the local maximum and the second edge (16) is arranged.

6. Carrier substrate (1) according to any one of the preceding claims, wherein the metal layer (12) outside of the flank profile (2), in particular in a central area provided as a useful area (17), has a first thickness (D1) and in the local maximum (21) has a second thickness (D2), wherein a ratio of the second thickness (D2) to the first thickness (D1) is less than 0.55, preferably less than 0.5 and particularly preferably less than 0.45.

7. Carrier substrate (1) according to one of the preceding claims, wherein an imaginary straight first connecting line (V1), which runs through the first edge (16) and the second edge (15), opposite a connection surface (25) over which the metal layer (12) is bonded to the insulating layer (11), is inclined by a first angle (W1), and wherein an imaginary straight second connection line (V2) passing through the second edge (16) and the local maximum (21). , relative to the connection surface (25) by the second angle (W2) is inclined.

8. The carrier substrate (1) according to any one of the preceding claims, wherein the flank profile (2), viewed in the primary direction, extends over a first length (L1) which is less than 1000 μm and preferably between 150 μm and 800 μm and particularly preferably between 300 μm pm and 600 pm.

9. Carrier substrate (1), in particular metal-ceramic substrate, comprising an insulation layer (11) and a metal layer (12), the metal layer (12) in a primary direction (P) running parallel to the main plane of extension (HSE) at least in regions having a Flank profile (2), in particular etched flank profile, ends, with the flank profile (2) starting from a first edge (15) on a top side (31) of the metal layer (12), which faces away from the insulating layer (11), as seen in the primary direction (P). is, extends up to a second edge (16) on an underside (32) of the metal layer (12), which faces the insulating layer (11), characterized in that the flank profile (2) in Seen in the primary direction (P) has at least one first section (A1) with a convexly curved profile and at least one second section (A2) with a concavely curved profile.

10. Carrier substrate (1) according to claim 9, wherein the convexly curved first section has a first radius of curvature (R1) which is greater than 200 μm, preferably greater than 400 μm and particularly preferably greater than 1000 μm and particularly preferably greater than 5000 μm , wherein the concavely curved second section (A2) preferably has a second radius of curvature (R2) which is larger or smaller than the first radius of curvature (R1).

11. Carrier substrate (1) according to one of the preceding claims, wherein a bonding layer (12) is formed between the metal layer (10) and the insulating layer (30) in the manufactured carrier substrate (1), and wherein an adhesion promoter layer (13) of the bonding layer ( 12) has a sheet resistance greater than 5 ohms/sq, preferably greater than 10 ohms/sq, and most preferably greater than 20 ohms/sq.

12. Carrier substrate (1) according to claim 11, wherein the bonding layer (12) is an adhesion-promoting layer (13) comprising an active metal and wherein a proportion of active metal in the adhesion-promoting layer (13) comprising an active metal is preferably greater than 15% by weight. %, preferably greater than 20% by weight and more preferably greater than 25% by weight.

13. A method for producing a carrier substrate (1) according to any one of the preceding claims, wherein the flank profile (2) is preferably produced by an etching step, in particular a single etching step.

14. A method for producing a carrier substrate (1) according to any one of the preceding claims, wherein a masking with a strip-shaped Masking section above the later edge course (2) is used.

15. A method for producing a carrier substrate (1), in particular a metal-ceramic substrate, according to any one of claims 1 to 13, comprising:

- Providing at least one metal layer (10) and one insulating layer (30), in particular a ceramic element (30), a glass element, a glass ceramic element and/or a high-temperature-resistant plastic element, the at least one metal layer (10) and the insulating layer (30) extend along a main extension plane (HSE),

- Arranging the at least one metal layer (10) and the insulating layer (30) in a direction perpendicular to the main extension plane (HSE) running the stacking direction (S) one above the other, wherein between the at least one metal layer (10) and the insulating layer (30) an active metal layer ( 15) is arranged, and

- Connecting the at least one metal layer (10) to the insulation layer (30) via the active metal layer (15) to form a bonding layer (12) between the at least one metal layer (10) and the insulation layer (30).