Method for stabilizing the relative lateral position of two components

Abstract

A method for sintering a first surface of a first component to a second surface of a second component. The method comprises applying a sintering layer to the second surface, providing a stabilizing device on the first surface, and placing the first component directly onto the sintering layer with the first surface facing the sintering layer, and wherein the stabilizing device protrudes into the sintering layer for stabilizing a lateral position of the first component relative to the second component, thereby forming a stable assembly to be sintered.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for sintering an interface surface of an attached object, e.g. a semiconductor power module, to an attachment side of a base part, e.g. to a heat dissipator, a heat sink and / or a cooler (a part for a cooler). BACKGROUND

[0002] The method is suitable for the manufacturing of a power module assembly. Such a power module assembly (in the following simply referred to as “assembly”) can comprise several attached objects fixed to a base part. Typically, the assembly is configured to form part of an electrical circuit, e.g. of a drive train circuit of an electric vehicle. Nowadays, the demand for electric vehicles, in particular electric cars, is rapidly growing.

[0003] The power module, in particular its attached objects, is adapted to exhibit the required electrical functionality. At least some of the attached objects can be semiconductor power modules. These can include insulated gate bipolar transistors (IGBT) and / or metal oxide semiconductor field effect transistors (MOSFET).

[0004] During operation of the electrical circuit, the attached objects generate heat, in particular due to the electric current. To avoid overheating and damage of the attached objects, they are fixed to a base part. Typically, the base part is a heat dissipator, a heat sink and / or a cooler (a part for a cooler). The base part receives a considerable part of the heat generated by the attached objects and further dissipates it. For example, the base part further releases the heat to ambient air via fins.

[0005] The attached objects should be fixed to the base part in a way that allows for sufficient heat transfer from the attached objects to the base part. In particular, the attached objects can be fixed to the base part by pressure sintering. A sintering layer composed of a sintering material is arranged between the attached objects and the base part. During a subsequent solidification step, the sintering material is heated to a maximum sintering temperature. Furthermore, the attached objects and the base part are pressed together, e.g. along a normal direction, which can be perpendicular to the attachment side. The solidification step densifies and solidifies the sintering material. A sintered body layer is formed by the sintering layer between the attached objects and the base part. The sintered body layer permanently fixes the attached objects to the base part.

[0006] The solidification step can be a bottleneck in the production of the assembly. It requires the use of a pressure sintering tool to press the attached objects and the base part against each other while heating the sintering material.

[0007] Each attachment object should be fixed to the base part at the correct position, i.e. at its respective predetermined position and by its respective predetermined spatial orientation. In order to use the maximum production capacity of the pressure sintering tool, the sintering layer is applied to the base part and the attachment objects are positioned on top of the sintering layer and outside the pressure sintering tool before the solidification step is started. The assembly to be sintered is put together and then moved into the pressure sintering tool. In this assembly, the attachment objects are correctly positioned on the sintering layer. Their interface surfaces face the sintering layer.

[0008] When the assembly is put together, the pressure sintering tool is not occupied while the solidification step for another assembly can be performed.

[0009] It is not sufficient to just place the attachment objects onto the sintering layer. The upper surface of the sintering layer is not very sticky, especially after some pre-drying, if any. In the assembly, the attachment objects do not have a significant adhesion to the sintering layer.

[0010] Furthermore, a shape mismatch of the interface surfaces of the attachment objects and the shape of the base part occurs at the attachment side where the attachment objects are fixed. When the attachment objects are placed onto the sintering layer before the solidification step, their interface surfaces do not fit or snugly rest on the sintering layer. This can lead to an unstable support of the attachment objects on the sintering layer. For example, the shape of the interface surfaces of the attachment objects can be convex. Thus, only a small contact area between the interface surfaces and the sintering layer exists. The attachment objects can wobble. Of course, other shape mismatches can occur as well.

[0011] Without additional measures, in these cases, when the assembly is moved into the pressurized tool, the risk is high that the attachment objects move away from their respective predetermined positions and / or deviate from the respective predetermined spatial orientations. The attachment objects can wobble and easily lose their correct position. Something is needed to keep them accurately in place when the assembly is moved, e.g. moved into the pressure sintering tool. Additionally or alternatively, unintentional skewing and lateral displacement of the attachment objects relative to the base part can still occur when the attachment objects are pressed against the base part and the convex interface surfaces flatten due to the pressure rise in the early stage of the solidification step.

[0012] The current method employs an alignment frame structure that holds the attached objects in the fitting part in their correct position, in particular during transfer of the fitting part into a pressure sintering tool and during a solidification step performed within the pressure sintering tool. The alignment frame structure comprises a frame that, for example, circumferentially surrounds the base part at least in a plane perpendicular to the normal direction. The alignment frame structure can comprise recesses for receiving the attached objects at their correct position. Additionally or alternatively, it can comprise pins that engage with corresponding holes in the base part and / or the attached objects.

[0013] The use of an alignment frame structure, in particular during transfer into a pressure sintering tool and during a solidification step, increases manufacturing time, manufacturing costs and manufacturing complexity. The alignment frame structure is only used temporarily. It is removed from the assembly after the solidification step. A proper alignment frame structure has to be specially designed for each assembly layout. The current method is suitable for small series production, but is too complex for mass production.

[0014] Furthermore, the alignment frame structure is complex and delicate in design. This leads to a considerable risk of failure. SUMMARY

[0015] It is an object of the present invention to facilitate manufacturing of an assembly as described above.

[0016] This problem is solved by the method according to claim 1.

[0017] The method is for sintering a first surface of a first part to a second surface of a second part. It comprises the following steps:

[0018] - applying a sintering layer onto the second surface;

[0019] - providing a stabilizing device on the first surface; and

[0020] - placing the first part directly onto the sintering layer, wherein the first surface faces the sintering layer, and wherein the stabilizing device protrudes into the sintering layer for stabilizing the lateral position of the first part relative to the second part, thereby forming a fitting part to be sintered.

[0021] The stabilizing device engages with the sintering layer and helps to fix the first part in its correct position in the fitting part. It stabilizes the position of the first part relative to the sintering layer and thus relative to the second part. There is no need to employ an additional alignment frame structure to ensure the correct position of the first part in the fitting part, for example during transfer of the fitting part into a pressure sintering tool or during a solidification step of the sintering material of the sintering layer to the sintered body layer. This facilitates manufacturing.

[0022] Since the alignment frame structure is not inserted into the pressure sintering tool together with the assembly, the pressure sintering tool can be smaller. Since no heat is wasted to at least partially heat the material of such an alignment frame structure in the pressure sintering tool during the solidification step, energy is saved.

[0023] When the first component is placed in its correct position on top of the sintering layer, its first surface faces the sintering layer. The first surface can at least partially directly abut the sintering layer. The stabilizing means protruding into the sintering layer exhibits a form fit between the stabilizing means and the sintering layer. Naturally, this stabilizes the first component to remain in its correct position. The stabilizing means engage the sintering layer, and the sintering layer eventually exhibits a predetermined mechanical stability. This engagement reduces the risk of the first component moving and / or deviating from its correct position in the assembly.

[0024] Of course, the method can involve sintering the first surfaces of a plurality of first components, e.g. the first surfaces of at least two first components, to the second surface of the second component. The disclosure relating to the “first component” and its fixation to the second component can each individually relate to one, more or all of the first components. According to the present disclosure, the fixation of different first components can comprise different modifications. Preferably, the fixation of the plurality of first components is performed by the same solidification step. According to one aspect, all first components can be fixed to the second component in the same way. The first components can be positioned spaced apart from each other in the assembly to be sintered (and accordingly in the resulting assembly).

[0025] According to one aspect, the assembly to be sintered is placed together outside the pressure sintering tool and then moved into the pressure sintering tool. The assembly to be sintered can be moved into the pressure sintering tool without using alignment frame means engaging the second component and the first component. In particular, the first component can be mechanically engaged with the second component only by:

[0026] • via the sintering layer

[0027] • and, optionally, in addition, directly by the stabilizing means protruding through the sintering layer and directly abutting the second surface assembly.

[0028] It has been found that by applying a sintering layer to the first surface of the first component or to the second surface of the second component, the same stability can be achieved in the assembly, provided that a stabilizing means is applied to the surface opposite to the surface to which the sintering layer has been applied.

[0029] Thus, in one embodiment, the first component can be an attachment object and the first surface can be an interface surface of the attachment object, and the second component is a base component and the second surface is an attachment side of the base component.

[0030] In an alternative embodiment, the first component can be a base component and the first surface can be an attachment side of the base component, and the second component is an attachment object and the second surface is an interface surface of the attachment object.

[0031] In one embodiment, the stabilizing means comprises at least one protrusion protruding from the interface surface. Irrespective of the additional stabilizing means, the interface surface is at least substantially flat after the solidification step. However, due to the convex shape of the interface surface prior to the solidification step (in particular in a fitting), at least a part of the interface surface can not directly abut the sintering layer in the fitting to be sintered (non-abutting part), while at least another part of the interface surface directly abuts the sintering layer (abutting part). When at least one protrusion protrudes from the interface surface, it protrudes towards the base component in the fitting to be sintered.

[0032] If several protrusions are provided, the disclosure relating to "protrusion" can individually refer to at least one, several or all protrusions. Different protrusions can be realized according to different disclosed modifications.

[0033] The protrusion can protrude from the interface surface, for example at least 125 pm in the direction of the normal. This ensures that even if the protrusion is arranged in the non-abutting part, the protrusion still protrudes into the sintering layer with an acceptable probability, taking into account the expected maximum convexity of the interface surface.

[0034] If the at least one protrusion is located in the abutting part, it protrudes deeply into the sintering layer. This exhibits a relatively strong engagement with the sintering layer.

[0035] If the at least one protrusion is located in the non-abutting part, it does not at all partially protrude into the sintering layer. Thus, now there are at least two different locations exhibiting an engagement between the attachment object and the sintering layer: the at least one abutting part and the at least one protrusion. This reduces the risk of the attachment object deviating from its respective intended spatial orientation, for example when the fitting is moved and / or the fitting is subjected to pressure sintering. Of course, this also further reduces the risk of the attachment object being displaced from its respective intended position relative to the base component.

[0036] In one embodiment, the stabilizing means comprises at least two protrusions protruding from the interface surface, wherein the at least two protrusions are spaced apart from each other. When the protrusions protrude from the interface surface, they protrude towards the base component in the fitting. Since the at least two protrusions protrude into the sintering layer in the fitting, the individual intended positioning and the individual intended alignment of the attachment object in the fitting to be sintered are ensured particularly reliably, even in the case of a particularly low adhesion of the interface surface to the sintering body layer (irrespective of the stabilizing means).

[0037] The stabilization device can comprise a plurality of protrusions protruding from the interface surface. The risk that the attached object cannot be held in place is further reduced with an increasing number of protrusions. For example, there can be at least 3 protrusions or even at least 24 protrusions.

[0038] In one embodiment, the stabilization device comprises at least three protrusions protruding from the interface surface. The at least three protrusions can be spaced apart from each other. It is ensured that the attached object rests at at least three different locations on the sinter layer. In other words, the attached object is supported on the sinter layer by at least three point supports. This prevents the attached object from wobbling on top of the sinter layer, even if the shape of the interface surface is convex.

[0039] According to another aspect, at least one protrusion is arranged at each corner portion of the interface surface, respectively. For example, the interface surface can be rectangular shaped and have four corner portions.

[0040] According to one aspect, parts of the stabilization device, for example the protrusions, can be concentrated at and / or in the vicinity of at least one region where the risk of a crack in the sinter body layer is expected to increase. These locations are for example edges and corners of the attached object and the sinter body layer, for example lateral ends (edges) of the sinter body layer in a plane perpendicular to the normal direction, in particular corners, or regions of the lateral ends (in particular corners) of the sinter body layer adjacent to the interface surface of the attached object. In the final assembly, the combination of the sinter layer and the stabilization device, if applicable, the remainder thereof, at least partially forms the remainder of the composite material. This inhibits the formation and / or propagation of cracks in the sinter body layer.

[0041] For example, the stabilization device can comprise a plurality of protrusions protruding from the interface surface, which are arranged along a circumferential outer portion of the interface surface. The protrusions can be equally spaced along the circumference. In at least one region where the risk of a crack in the sinter body layer is particularly high, it is also possible that the spatial density of the protrusions increases. For example, the protrusions are arranged substantially equidistantly along the edges of the sinter body layer and / or adjacent to the edges of the interface surface, but have a more dense (narrower) arrangement at the corners of the sinter body layer and / or adjacent to the corners of the interface surface.

[0042] The protrusions (or the remainder thereof) locally increase the thermal cycle resistance (TC resistance) of the sinter body layer. The TC resistance refers to the resistance against damage by thermal cycling. In operation of the assembly, the attached object (for example in the form of a molded semiconductor power module) can generate heat. The temperature of the attached object, the sinter layer and the attachment side can vary in operation. This leads to a thermal cycling of the sinter body layer between the attached object and the attachment side. Thermal induced stresses are higher at the edges of the sinter body layer and / or the interface surface and are particularly high at the corners of the sinter body layer and / or the interface surface. The thermal cycling can lead to crack formation and crack propagation in the sinter body layer.

[0043] Arranging a number of protrusions, e.g. wire-bonding structures, around the edge of an object, e.g. a molded module with a DCB structure (see below), inhibits the propagation of cracks from the edge, where the probability of crack formation is expected to increase, in a similar way as in the case of fiber-reinforced plastics, e.g. glass fibers, or the like. In homogeneous materials, cracks usually propagate more easily. In materials that are rich in objects that exhibit different physical properties, like the protrusions or the remainder thereof in this case, or the glass fibers in the case of glass fibers, the tip of the crack is repeatedly blunted, which slows down the propagation of the crack.

[0044] According to an aspect, the lateral distance between adjacent protrusions can be less than 0.5 mm. The lateral distance can be measured at the location where the protrusion is fixed to the interface surface.

[0045] The protrusions can locally influence the heat conduction in the sintered layer and / or the sintered body layer.

[0046] The stabilizing device can comprise elements that are fixed to the interface surface and / or elements that are directly formed in one piece with the interface surface.

[0047] The method can comprise the step of forming at least a portion of the stabilizing device on the interface surface by wire-bonding, e.g. by a wire-bonder. The position of the portions of the stabilizing device that are formed by this technique can be controlled very precisely. This technique can easily be implemented in existing manufacturing practice. It is particularly suitable to concentrate portions of the stabilizing device, e.g. protrusions, at specific locations in a very precise manner. This is a cost- and time-efficient method of fixing the stabilizing device to the interface surface. The bonding wires used for wire-bonding are compatible with the sintering process. They do not affect the sintering process.

[0048] The thickness of the bonding wires used can be in the range of 90 pm to 200 pm, e.g. in the range of 100 pm to 140 pm. This allows to create very fine structures.

[0049] In one embodiment, the stabilizing device comprises at least one wire-bonding structure. As described above, the wire-bonding structure can be formed by wire-bonding. It can be fixed to the interface surface by ultrasonic welding.

[0050] For example, the at least one protrusion can be a wire-bonding structure formed by a wire-bonder.

[0051] Thus, the at least two protrusions can each be formed as a wire-bonding structure by a wire-bonder.

[0052] In particular, the at least one wire bonding structure can be a bond. A bond is a wire bonding structure that is fixed to the interface surface by a free end portion of the wire. In other words, the free end portion of the wire is not directly fixed to the interface surface, but another portion of the wire, for example at least another end of the wire, is fixed to the interface surface, for example by melting through an ultrasonic welding process. Even after the pre-drying of the sinter layer has been completed, sharp bonds can easily penetrate the sinter layer.

[0053] At least one, several or all of the wire bonding structures can be a bond. At least one, several or all of the protrusions can be a bond.

[0054] In one embodiment, the at least one wire bonding structure can be a ball bond. Typically, at least one, several or all of the wire bonding structures can be a ball bond.

[0055] In one embodiment, the stabilizing means is made of a sinterable material. By "sinterable material" can be meant a material that bonds well with the sinter body layer during the solidification step. For example, the wire bonding structure(s) can be made by using wire(s) of sinterable material, for example copper, silver and / or aluminum, including alloys based on at least one of these materials. In particular, the stabilizing means can be made of a material that sintered together with the sinter material in the solidification step. In one embodiment, the stabilizing means is made of a material that can sinter together with the sinter layer in the solidification step but is different from the metal proportion of the sinter material. On the one hand, this facilitates a firm permanent fixation of the attachment object to the base part after the solidification step, but on the other hand, it facilitates the suppression of crack formation and / or propagation in the sinter body layer.

[0056] In one embodiment, at least one, several or all of the protrusions can comprise a glob of glue. According to another aspect, at least one, several or all of the protrusions can comprise a sharp burr at the interface surface. The sharp burr can be formed by cutting and / or scraping into the interface surface. According to another aspect, at least one, several or all of the protrusions are created by fixing a solid protruding object, for example made of metal, to the interface surface.

[0057] The stabilizing means can comprise different types of protrusions.

[0058] According to another aspect, the method can comprise the step of applying a sinter material onto the attachment side to form the sinter layer.

[0059] If the fitting comprises a plurality of attachment objects, the sinter layer can comprise a plurality of portions, for example one portion per attachment object. Different portions of the sinter layer can be spaced apart from each other.

[0060] The sintering material can comprise a sintering paste and / or a sintering slurry (alternatively referred to as a sintering preform), in particular formed from a sintering paste and / or a sintering slurry.

[0061] The sintering material can comprise metal particles and at least one volatile component. The metal particles can comprise and / or be silver particles and / or copper particles. The volatile component(s) can be organic. The density of the sintering material can be in the range of 2.5 g / cm 3 to 3.5 g / cm 3 .

[0062] The sintering material (sintering paste and / or sintering slurry) can be pre-dried. In particular, the method can comprise the step of pre-drying the sintering material, for example after application and before placing the attachment object onto the attachment side, with the sintering layer between the attachment object and the attachment side. At least a portion of the volatile organic component can evaporate during pre-drying.

[0063] The sintering material can be applied in a wet state in the step of application before pre-drying.

[0064] By pre-drying, the sintering material becomes more like a solid material compared to a wet state. The sintering slurry can stick to the attachment surface because it is a slurry. The pre-dried sintering layer can be firmly attached to the attachment side. As the sintering material becomes more like a solid material by pre-drying, it exhibits more resistance to drag the stabilizing device parallel to the attachment side.

[0065] The pre-dried sintering layer can be porous after evaporation of the volatile component(s). Thus, the stabilizing device can penetrate the sintering layer even after pre-drying has been completed.

[0066] The thickness (in the direction of the normal) of the sintering layer can be in the range of 80 pm to 200 pm, for example 100 pm.

[0067] The method can comprise the step of placing the attachment object onto the applied sintering layer by a robot. This allows for cost-efficient production with high production capacity and high precision. As no complex alignment frame structure is needed, it is much easier to use a robot for this task.

[0068] The pre-drying (step) can be performed before, during and / or after the step of placing the attachment object onto the sintering layer. The pre-drying can be completed at the latest before the fitting part is inserted into the pressure sintering tool, in particular before the fitting part is moved for insertion into the pressure sintering tool. For example, the pre-drying can be considered complete when at least 70 wt.-% of the volatile compounds have evaporated.

[0069] For example, the attachment object can be placed onto the pre-dried sintering material. In particular, the step of placing the attachment object onto the applied sintering layer is performed after the pre-drying is completed (e.g. at least 70 wt.% of the volatile compounds are evaporated).

[0070] The solidification step can be performed with the pre-dried sintering material.

[0071] According to one aspect, the method comprises the step of inserting the assembly to be sintered into the pressure sintering tool, wherein the placing of the attachment object onto the sintering layer occurs before the assembly to be sintered is inserted into the pressure sintering tool. In other words, the method can comprise the step of moving the assembly to be sintered into the pressure sintering tool. In particular, the assembly to be sintered can be inserted into the pressure sintering tool without the need for an alignment frame structure for holding the attachment object in the assembly in its correct position.

[0072] According to another aspect, the method comprises a solidification step for solidifying the sintering layer in the assembly to be sintered. Thereby, the attachment object becomes rigidly and permanently fixed to the base part.

[0073] The solidification step can comprise sintering the sintering layer (for permanently fixing the at least one attachment object to the base part) with a maximum sintering temperature in the range of 200 °C to 300 °C and / or with a maximum sintering pressure in the range of 10 MPa to 40 MPa. This ensures proper sintering and thus a rigid and secure fixation of the attachment object to the base part.

[0074] The solidification step can be performed with the pressure sintering tool.

[0075] In one embodiment, the thickness (e.g. along the normal direction) of the sintering layer is at most 70 pm. Additionally or alternatively, the thickness of the sintering layer can be at least 20 pm. The thickness of the sintering layer can be 50 pm ± V. For example, V can be 10 pm or 6 pm. The thickness of the sintering layer can be smaller than the width of the preceding sintering layer. The density of the sintering layer can be higher than the density of the preceding sintering layer. The sintering layer can be made of at least 90 wt.% (possibly at least 96 wt.%) of metal, e.g. resulting from the metallic material proportion of the sintering material. The density of the sintering layer can at least substantially correspond to the density of the metallic material proportion of the sintering material.

[0076] The stabilizing means can become at least partially permanently compressed (at least partially reduced in height) during the curing step. As mentioned above, the stabilizing means can comprise protrusions formed by joining leads having a diameter of 125 pm. Furthermore, the sintering layer should be thin to allow for good heat transfer from the attachment object to the base part, e.g. a thickness of at most 70 pm. Even in case the interface surface of the attachment object is initially convexly shaped, it has become flat already at a late stage of the curing step. The force pressing the attachment object against the base part and the resulting counterforce from the sintering layer and the stabilizing means being squeezed between the interface surface and the base part flattens the interface surface. Furthermore, due to the relative friction between the attachment object, the sintering layer and the base part and due to the late curing (hardening) of the sintering layer, the stabilizing means are no longer needed to hold the attachment object in its correct position. Thus, there is no issue causing the stabilizing means to become at least partially permanently compressed during the curing step. It was also found that this does not impair the sintering process.

[0077] According to one aspect, the stabilizing means can be made of a different material than the interface surface. For example, the hardness and / or the yield strength of the (material of the) stabilizing means can be smaller than the hardness and / or the yield strength of the (material of the) interface surface. This reduces the risk of the interface surface being damaged if the stabilizing means is compressed during the curing step.

[0078] According to another aspect, the attachment object is or comprises at least one of:

[0079] - a heat generating component,

[0080] - an electronic component, e.g. a semiconductor component, and

[0081] - a semiconductor power module.

[0082] In particular, the attachment object can be a semiconductor power module. The semiconductor power module can comprise at least one semiconductor component.

[0083] The electronic component and the semiconductor power module generate heat during operation; thus they can also be considered as heat generating components, respectively.

[0084] The semiconductor component can comprise or consist of a semiconductor switch, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), etc.

[0085] In particular, the attachment object can comprise or consist of a molded module. The molded module can be a semiconductor power module comprising a resin cap. The resin cap can be manufactured by transfer resin molding. If multiple attachment objects are fixed to the patterned object, at least one of them, a part of them or all of them can comprise or consist of a molded module, respectively.

[0086] The semiconductor power module itself can comprise different layers and / or components.

[0087] The semiconductor power module can comprise any one, several or all of:

[0088] - an integrated heat spreader,

[0089] - an insulation layer,

[0090] - an (internal) circuit layer,

[0091] - a fixing layer (e.g. an internal sintering layer) for fixing the semiconductor components to the insulation layer and / or the circuit layer,

[0092] - semiconductor components,

[0093] - bonding wires, and

[0094] - a resin cover (“molded module”).

[0095] The insulation layer can be made of a ceramic material. The (internal) circuit layer can be fixed to the insulation layer. Additionally or alternatively, the integrated heat spreader can be fixed to the insulation layer. The integrated heat spreader can be arranged at the interface surface. In particular, it can constitute the interface surface. The insulation layer can be provided between the integrated heat spreader and the (internal) circuit layer.

[0096] In one embodiment, the attached object (e.g. the semiconductor power module) comprises a direct copper bonded (DCB) structure. It can comprise a substrate forming the insulation layer, e.g. a ceramic substrate. Further, the DCB structure can comprise the insulation layer, and one or both of the (internal) circuit layer and the integrated heat spreader.

[0097] According to another aspect, the patterned object is or comprises a heat dissipator, a heat sink and / or a cooler (part of a cooler).

[0098] In one embodiment, the attachment side of the base component is made of metal. Additionally or alternatively, the interface surface is made of metal. This allows for a good transfer and dissipation of heat generated in the attached object.

[0099] The above-mentioned problems are further solved by an assembly comprising a base component and an attached object, wherein a sintering layer between an interface surface of the attached object and an attachment side of the base component fixes the attached object to the base component, wherein a stabilizing device formed on the interface surface or at least a remainder thereof protrudes into the sintering layer.

[0100] Features and advantages described with respect to the method apply correspondingly to the assembly and vice versa. For example, as described above, the stabilizing device (e.g. the protrusion, or a remainder thereof) can suppress the formation and / or propagation of cracks.

[0101] According to an aspect, the attachment object can have been (permanently) fixed to the base object using the method disclosed herein.

[0102] The assembly can be adapted to exhibit an electrical function. For example, it can be adapted to switch a current.

[0103] The assembly can be configured to be electrically connected to other electrical and / or electronic components.

[0104] In an embodiment, the assembly is configured to form part of an electrical circuit.

[0105] The assembly can be configured to form part of a drive train circuit, for example in an electric vehicle. The electric vehicle can comprise an electric car, truck, electric train, marine vehicle (e.g. ship and boat), airplane, etc. The drive train circuit can be a circuit for an electric motor, an electric drive train, a hybrid electric drive train, a battery electric drive train, and / or the like. For example, the assembly can be a multi-chip automotive traction power module. In general, the drive train circuit can be configured for mobile, semi-mobile, and / or stationary applications. For example, drive train circuits for compressors, cable cars, stationary cranes, pumps, etc. are also contemplated.

[0106] According to an aspect, the assembly is configured to form part of an inverter circuit. The assembly can be used in an inverter, for example in a drive train circuit.

[0107] According to an aspect, the assembly is a half-bridge power assembly.

[0108] The above-mentioned problems are further solved by a fitting piece to be sintered for fixing an interface surface of an attachment object to an attachment side of a base component by sintering, the fitting piece comprising:

[0109] a base component;

[0110] an attachment object; and

[0111] a sintering layer arranged between the attachment side and the interface surface;

[0112] wherein a stabilizing means for stabilizing a lateral position of the attachment object relative to the base component is formed on the interface surface, wherein the stabilizing means protrudes into the sintering layer for stabilizing the lateral position of the attachment object relative to the base component.

[0113] Features and advantages described in relation to the method and assembly apply correspondingly to the fitting piece to be sintered and vice versa.

[0114] The fitting piece to be sintered can be adapted for producing the assembly.

[0115] The additional features, advantages and possible applications of the application will be apparent from the following description of exemplary embodiments and drawings. All features described herein in the drawings and / or illustrated graphically form the subject matter of the application, either alone or in any desired combination, regardless of whether they are combined in the claims or in their references to the aforementioned claims. BRIEF DESCRIPTION OF DRAWINGS

[0116] Preferred embodiments of the application will now be described with reference to the accompanying drawings, in which:

[0117] Figure 1 A cross-sectional view of a base component is shown, wherein a sintering layer is applied to the attachment side of the base component and a semiconductor power module is placed onto the sintering layer, wherein the semiconductor power module comprises stabilizing means protruding from the interface surface of the semiconductor power module for engaging the sintering layer, in particular for being stabbed into the sintering layer;

[0118] Figure 2 A cross-sectional view of a mating piece to be sintered is shown, comprising Figure 1 a base component with a sintering layer as shown in Fig. 1 and a semiconductor power module as shown in Fig. 2, wherein the semiconductor power module is placed onto the sintering layer, wherein the stabilizing means protrude into the sintering layer, thereby stabilizing the lateral position of the semiconductor power module relative to the base component;

[0119] Figure 3 A cross-sectional view of an assembly formed by Figure 2 a mating piece to be sintered as shown in Fig. 3 by pressure sintering;

[0120] Figure 4 A view onto the interface surface of the semiconductor power module of Figure 1 is shown;

[0121] Figure 5 A flow chart of a method for sintering the interface surface of a semiconductor power module to the attachment side of a base component is shown; and

[0122] Figures 6A to 6E Various embodiments of protrusions of stabilizing means are shown.

[0123] Figure 7 A cross-sectional view of an embodiment of two components ready for joining using the method of the application is shown.

[0124] Figure 8 A cross-sectional view of a mating piece formed by Figure 7 the components as shown in Fig. 3 is shown. DETAILED DESCRIPTION

[0125] Figure 1is a cross-sectional view showing the base component 10 and an attached object that shall be fixed to the attachment side 11 of the base component 10 by pressure sintering to finally produce an assembly 60 as shown in Figure 3

[0126] In this example, the attached module is a semiconductor power module 30, more specifically a semiconductor power module 30 with a resin cover 40 (which can be referred to as a molded semiconductor power module).

[0127] The semiconductor power module 30 comprises a direct bonded copper (DCB) structure with a ceramic insulating layer 34, an integrated heat sink 33 and an internal circuit layer 35. A side of the integrated heat sink 33 facing away from the insulating layer 34 constitutes the interface surface 31. The integrated heat sink 33 is formed on a side of the insulating layer 34 and fixed to the insulating layer 34. The internal circuit layer 35 is formed on the opposite side of the insulating layer 34 (e.g., the upper side in Figure 1 ) and fixed to this opposite side of the insulating layer 34. Semiconductor components 37 are fixed to the internal circuit layer 35 by an internal sinter body layer 36. The internal sinter body layer 36 can comprise separate portions for some or each of the semiconductor components 37. The semiconductor components 37 comprise, for example, IGBTs and / or MOSFETs. The semiconductor power module 30 can further comprise internal wiring 38, for example, for forming electrical connections between the semiconductor components 37 and the internal circuit layer 35. Furthermore, the semiconductor power module 30 can comprise electrical connectors 39. The electrical connectors 39 can be used to establish electrical connections with other attached objects (not shown), for example, other semiconductor power modules, which become fixed to the same base component 30 and / or with other electrical components.

[0128] The optional resin cover 40 covers the entire semiconductor power module 30 except for the integrated heat sink 33 at the interface surface 31. The resin cover 40 has electrical insulation, moisture resistance, and protection against mechanical and chemical damage.

[0129] The semiconductor power module 30 is adapted to provide at least one electrical function in the final assembly 60, for example, for switching electrical currents. In operation, the semiconductor power module 30 generates heat. By fixing the semiconductor power module 30 to the base component 10, heat dissipation is improved and overheating of the semiconductor power module 30 during operation is prevented.

[0130] In the assembly 60, the base component 10 is used to dissipate heat generated by the semiconductor power module 30. For example, the base component 10 can be a heat sink with fins, for example, rectangular fins and / or pin fins (not shown). Additionally or alternatively, the base component 10 can be a cooler or a part for forming a cooler. The base component 10 can comprise a channel structure for guiding a fluid, for example, a coolant.​

[0131] The base part 10 can be made of aluminum and / or copper (including respective alloys). In one variant (not shown), the base part 10 is made of aluminum (including aluminum alloys) and comprises an inlay at the contact area, wherein the inlay is made of copper (including copper alloys).

[0132] The attached object is rigidly and permanently fixed to the base part 10 by pressure sintering.

[0133] The attachment side 11 of the base object 10 is substantially flat at least in the contact area where the attached object (semiconductor power module 30) becomes fixed. The normal direction N is perpendicular to said contact area. In this example, the entire attachment side 11 is flat and the normal direction N is perpendicular to the entire attachment side 11.

[0134] An example of a respective method for pressure sintering an interface surface 31 of an attached object (e.g. a semiconductor power module 30) to an attachment side 11 of a base part 10 is described in more detail below with reference to Figure 5 and other figures.

[0135] In a sintering layer application step S20, a sintering material is applied to the attachment side 11 of the base part 10 in order to form a sintering layer 20 which is to be subjected to pressure sintering in a subsequent solidification step S60. The sintering layer 20 is formed at least at the contact area of the attachment side 11 for attaching the attached object. In this example, the sintering layer 20 is formed by using a sintering paste. The sintering paste is spread onto the attachment side 11, at least onto said contact area. It comprises a finely divided metal, e.g. silver, copper and / or another metal. In the present example, silver and / or copper are used as the metal (including respective alloys). In the sintering layer application step S20, the sintering paste is applied in a wet state. The sintering paste comprises liquid organic volatile compounds. This facilitates correct application of the sintering paste. The density of the sintering paste can be in the range of 2.5 g / cm 3 to 3.5 g / cm 3 .

[0136] Figure 1 The base part 10 is shown, wherein one portion (one patch) of the sintering layer 20 is applied on the attachment side 11. Of course, this portion can be larger, in particular if several attached objects are to be pressure sintered to the base part 10 by the same portion. Additionally or alternatively, the sintering layer 20 can comprise multiple portions (patches) for pressure sintering different attached objects to the base part 10.

[0137] A pre-drying step S30 can be performed on the sintered layer 20. In the pre-drying step S30, at least a part of the volatile components evaporates. In other words, the sintered layer 20 is at least partially dried during the pre-drying step S30. The pre-drying step S20 can comprise leaving the base part 10 with the applied sintered layer 20 at rest for at least a predetermined time. When the sintered layer 20 dries, it becomes more like a solid but sponge-like material (with voids). The sintered layer 20 also becomes firmly attached to the attachment side 11.

[0138] The thickness of the (pre-dried) sintered layer 20 (in the normal direction N) can be in the range of 80 pm to 200 pm. The thickness can not be, at least not substantially, affected by the pre-drying step S30. For example, the thickness after pre-drying can differ less than 20% from the thickness before pre-drying.

[0139] Figure 2 A kit 50 to be sintered is shown. The kit 50 comprises a base part 10, a sintered layer 20 applied to the attachment side 11, and an attachment object (here in the form of a semiconductor power module 30) placed onto the sintered layer 20 (on top of it) in the correct position of the sintered layer 20.

[0140] The interface surface 31 of the attachment module (in this case the semiconductor power module 30) is typically convex. This is the case because the interface surface 31 is formed by the top side of the semiconductor power module 30. The top side of the semiconductor power module 30 is typically convex because of the different coefficients of thermal expansion of the elements that make up the semiconductor power module 30. Figure 1 and Figure 2 This is shown schematically in Figs. 1 1 and 12. The convex shape can result from the different coefficients of thermal expansion of the elements that make up the semiconductor power module 30.

[0141] In a conventional embodiment (not shown), the interface surface 31 of the semiconductor power module 30 is flat and smooth, except for the convex curvature. Because of the convex curvature, only a small part of the interface surface 31 (only a small part of the underside of the integrated heat sink 33) directly abuts the top of the sintered layer 20. As a result, the semiconductor power module can easily swing, twist and / or be laterally displaced with respect to the base part 10. This will impair the correct manufacturing. Therefore, by convention, the kit 50 would exclude a specially designed connection frame structure in order to hold the semiconductor power module 30 in its correct lateral position as intended for the final assembly 60. “Lateral” can mean perpendicular to the normal direction N (parallel to the Figure 2 the attachment side 11 in Fig. 1 1).

[0142] According to the application, the method comprises a step S10 of providing stabilizing means on the interface surface 31. If the attached object, i.e. the semiconductor power module 30, is placed on the sintering layer 20, which can have been pre-dried before, the stabilizing means are configured to protrude into the sintering layer 20 and stabilize the lateral position of the attached object with respect to the base part 10. Thus, it is not necessary to use an additional alignment frame structure for stabilizing the attached object in its correct lateral position with respect to the base part 10. The assembly 50 to be sintered does not comprise such an additional alignment frame structure and is handled without such an additional alignment frame structure.

[0143] In this example, the step S10 comprises providing a plurality of protrusions 32 at the interface surface 31. The protrusions 32 protrude from the interface surface 31, in this example from the lower side of the integrated heat sink 33.

[0144] The protrusions 32 can be produced by means of an ultrasonic wire bonder. The protrusions 32 can be wire bonding structures. In particular, they can be formed as so-called bond-offs. For producing such bond-offs, the wire bonder fixes the end portions of bonding wires to the interface surface 31, to the integrated heat sink 33, by means of ultrasonic waves. Then, the bonding wires are cut to separate the bonding wire segments that are fixed to the interface surface 31.

[0145] The diameter of the bonding wires, and thus of the bonding wire segments that constitute the protrusions 32, the stabilizing means, can be, for example, 125 pm.

[0146] The stabilizing means can be made of a sinterable material. It can be made of a sinterable metal, for example copper, silver and / or gold, including alloys based on one or several of these metals. The bonding wires can be made of a corresponding material.

[0147] In a placing step S40, the attached object is placed onto the sintering layer 20. The placing step S40 can comprise automatically aligning the attached object with respect to the base part 10. For example, the attached object can be placed by at least one robot into the correct position on the sintering layer 20. The correct position is Figure 3 the intended lateral position in the final assembly 60 as shown.

[0148] The placing step S40 can comprise placing several attached objects into their respective correct positions on the sintering layer 20.

[0149] The placing step S40 results in forming the assembly 50 to be sintered as shown. Figure 2

[0150] ​In the fitting 50, the stabilizing means (in this example, the protrusions 32) protrude deeply into the sintering layer 20. In more detail, in this example, sharp engagement objects are pushed into the pre-dried sintering layer 20. They are pierced into the sintering layer 20.

[0151] The pre-dried sintering layer 20 is similar to snow, as it can be further compressed and it resists the pulling of the stabilizing means transversely to the normal direction N (i.e. parallel to the attachment side 11).

[0152] The stabilizing means protruding into the sintering layer 20 stabilize the correct position of the attached object relative to the sintering layer 20 and, thus, relative to the base part 10. This allows handling the fitting 50 to be sintered without using additional alignment frame structures without laterally displacing or twisting the attached object out of its correct position. Since in this example multiple protrusions 32 are provided, the attached object cannot swing, either.

[0153] In a transfer step S50, the fitting 50 to be sintered is moved and inserted into a pressure sintering tool. The transfer step S50 is performed without additional alignment frame structures.

[0154] In a solidification step S60, the sintering layer 20 is transformed into a sintered body layer 20a. Thereby, the attached object (in this example, the semiconductor power module 30) becomes firm, rigid and permanently fixed to the base part 10. The solidification step 60 is performed in a pressure sintering tool. The solidification step 60 comprises, for example, pressing the attached object and the base part 10 towards each other along the normal direction N. The sintering layer 20 is pressed between the interface surface 31 and the attachment side 11. Furthermore, heat is provided, for example by the pressure sintering tool, for heating the sintering layer 20. Due to the combined application of pressure and heat to the sintering layer 20, the sintering layer 20 is transformed into the sintered body layer 20a. The stabilizing means do not impair the sintering process.

[0155] During the solidification step S60, the sintering layer 20 is heated to a maximum sintering temperature in the range of 200 °C to 300 °C. The pressure applied to the sintering layer 20 can be in the range of 10 MPa to 40 MPa. In the solidification step S60, the temperature can be kept in the range of the sintering temperature and / or the pressure applied to the sintering layer 20 can be kept in the range of the sintering pressure for a duration in the range of 2 minutes to 10 minutes.

[0156] The thickness of the sintered body layer 20a (in the normal direction N) can be less than the thickness of the previous sintering layer 20. For example, the thickness of the sintered body layer 20a can be in the range of 40 pm to 60 pm, for example 50 pm.

[0157] Such a sintered body layer 20a (ignoring the stabilizing device or its remaining portion 32a) consists of the metal proportion contained in the original sintering paste. The density of the sintered body layer 20a is higher than the density of the earlier (pre-dried) sintered layer 20. For example, the density of the sintered body layer 20a is similar to the density of the metal proportion (e.g. about 10.5 g / cm3if the metal proportion is silver, or about 9 g / cm3if it is copper). 3 3 ) if it is copper.

[0158] Figure 3 The final assembly 60 produced from the assembly piece 50 to be sintered as shown in Fig. 6 is shown, wherein the production comprises a solidification step S60. Figure 2

[0159] In this example, the original diameter of the joining leads (and thus of the protrusions 32) is larger than the thickness of the sintered body layer 20a. Thus, the stabilizing devices (protrusions 32) are deformed during the solidification step S60. The remaining portions 32a of the stabilizing devices are embedded in the final sintered body 20a.

[0160] The material of the stabilizing devices can be softer (e.g. lower hardness and / or yield strength) than the material of the integrated heat spreader 33 and / or the material of the base component 10 at the attachment surface. This allows the stabilizing devices to be deformed in the solidification step S60 without damaging the attachment module and / or the base component 10.

[0161] The material of the stabilizing devices and their remaining portions 32a on the one hand and the material of the sintered body layer 20a on the other hand can be different. Thus, the stabilizing devices or the remaining portions 32a (in case the stabilizing devices deform significantly during the solidification step S60) at least locally form a composite material in the final assembly 60 as shown in Fig. 6. Figure 3

[0162] The stabilizing devices or the remaining portions 32a in the sintered body layer 20a can locally influence the thermal conductivity between the attached object and the base component 10.

[0163] As mentioned above, the attached object can generate heat during operation, e.g. when the assembly 60 switches current. The amount of heat generated per time unit and thus the temperature of the attached object (e.g. at the integrated heat spreader 33) varies depending on the operating state. Due to the difference in the coefficient of thermal expansion, the rigid connection between the attached object and the base component 10 via the sintered body layer 20a is subject to stresses resulting from thermal cycling. This can lead to the formation and propagation (growth) of cracks in the sintered body layer 20a.

[0164] ​​​The local composite structure in the layer of sintered bodies 20a resulting from the embedded stabilizing devices or their remaining portions 32a locally inhibits the formation and propagation of cracks in the layer of sintered bodies 20a. The boundaries between the different materials can redistribute local stresses and strains and act as a barrier to crack propagation.

[0165] According to an aspect, the stabilizing devices, e.g. in the form of the protrusions 32 provided as joints, are concentrated at and / or in the vicinity of areas of the layer of sintered bodies 20a where the risk of breakage is increased. These areas are, for example, areas of the layer of sintered bodies 20a under the peripheral area of the integrated heat sink 33 (in a plane parallel to the normal direction N), i.e. under the edge area of the integrated heat sink 33, in particular under the corner areas. Thus, the stabilizing devices can be concentrated at the respective areas at the integrated heat sink 33.

[0166] Figure 4 A view of the lower side of the attachment module 30 before the execution of the solidification step S60 is shown. The protrusions 32 are provided at the lower side of the integrated heat sink 33. In more detail, they are arranged equidistantly along the circumferential outer portion 31a of the lower side of the integrated heat sink 33. Thus, in the shown embodiment, the protrusions 32 are arranged in a circle around the integrated heat sink 33. Figure 3 In the shown final assembly 60, the protrusions 32 or at least their remaining portions 32a are located in areas of the layer of sintered bodies 20a where the risk of breakage is highest. This increases the resistance of the assembly 60 (in particular the sintered layer 20) against thermal cycling and thus the reliability of the assembly 60. As Figure 4 As shown, the lower portion of the resin cap 40 can laterally pass around the peripheral area of the integrated heat sink 33. It can be considered that the lower portion of the resin cap 40 does not form a part of the interface surface 31, as the resin material does not form a firm connection with the layer of sintered bodies 20a.

[0167] Of course, the method can comprise pressure sintering the interface surfaces of several attachment objects (e.g. several semiconductor power modules 30) to the attachment side 11 of the base part. Correspondingly, the counterpart 50 can comprise several attachment objects.

[0168] The assembly 60 is configured to form a part of an electrical circuit, e.g. a drive train circuit for mobile, semi-mobile and / or stationary applications. The electrical connectors 39 can be used to integrate the assembly 60 in the electrical circuit.

[0169] Figures 6A to 6E Different embodiments of the protrusions 32 provided at the interface side 31 are shown.

[0170] In Figure 6A In the shown embodiment, the single protrusions 32 are formed as short wire bonds (joints), as described above.

[0171] Figure 6BAn embodiment of a protrusion 32 formed by ball bonding is shown. In this case, the protrusion 32 comprises a ball portion 321 fixed to the interface surface 31 and an additional 322 protruding further away from the interface surface 31 than the ball portion 321. In a first step, the ball portion 321 is formed at the interface side 31. For this, the bonding wire is fed through a capillary of a bonding tool and subjected to a high voltage charge. As a result, the end of the bonding wire metal is melted at the tip of the capillary. Due to the surface tension of the molten metal, a ball portion 321 is preformed at the end of the bonding wire. The preformed ball portion 321 cools and at least partially solidifies. The preformed ball portion 321 is pushed against the interface surface 31 and fixed to the interface surface 31, for example by ultrasonic welding. In a second step, the capillary is lifted away from the interface surface 31 while the bonding wire is further fed through the capillary. Then, the bonding wire is cut. This results in the additional 322 on top of the ball portion 321.

[0172] In Figure 6C In the shown embodiment, the protrusion 32 is formed by a solid (metallic) object 323 fixed to the interface surface 31. This ensures that the protrusion 32 has a very precise shape. The solid object 323 can have a sharp peak (as shown). The solid object 323 is provided (e.g. pre-fabricated) as a separate element and then welded, glued and / or soldered to the interface surface 31. For example, the solid object 323 can be fixed by an ultrasonic welding process. Figure 6C

[0173] Another method is shown in Figure 6D In this case, the protrusion 32 is a glue drop 324. The glue drop 324 has a sharp peak. To create the glue drop 324, a material can be applied as a viscous liquid onto the interface surface 31 and then solidified. In one embodiment, the glue drop 324 is formed by a hot-melt glue.

[0174] Figure 6E Another embodiment of a protrusion 32 is shown. In this case, the protrusion 32 is a sharp burr 325. An exemplary sharp tool 326 used to form the burr 325 is shown by the dashed line. The sharp tool 326 is pushed into the interface surface 31 of the attachment object 30 such that a small portion of the interface surface 31 is raised as the sharp protrusion 32.

[0175] Figure 7 A first component 130 and a second component 110 are shown ready to use the method of the invention to sinter the first surface 131 of the first component 130 to the second surface 111 of the second component 110. A sintering layer 20 has been applied to the second surface 111 of the second component 110 and a stabilizing device 32 has been provided on the first surface 131 of the first component. ​

[0176] Figure 8 A fitted part 50 is shown which is formed by placing the first part 130 directly onto the sintering layer 20 with the first surface 131 of the first part facing the sintering layer 20 and with the stabilizing means 32 protruding into the sintering layer 20 for stabilizing the lateral position of the first part 130 relative to the second part 110. The thus formed fitted part 50 is suitable for moving and inserting into a pressure sintering tool without any additional alignment frame structure.

[0177] List of reference signs:

[0178] 10 base part

[0179] 11 add-on side

[0180] 20 sintering layer

[0181] 20a sinter body layer

[0182] 30 semiconductor power module (attached object)

[0183] 31 interface surface

[0184] 31a circumferential outer part

[0185] 32 stabilizing means

[0186] 32a remaining part (of the stabilizing means)

[0187] 33 integrated heat sink

[0188] 34 insulating layer

[0189] 35 inner circuit layer

[0190] 36 inner sinter body layer

[0191] 37 semiconductor part

[0192] 38 inner connection

[0193] 39 electrical connector

[0194] 40 resin cover

[0195] 50 fitted part (to be sintered)

[0196] 60 assembly

[0197] 110 second part

[0198] 111 second surface

[0199] 130 first part

[0200] 131 first surface

[0201] 321 spherical portion

[0202] 322 add-on

[0203] 323 solid metal object

[0204] 324 globule

[0205] 325 burr

[0206] 326 tool

[0207] N normal direction

[0208] S10 providing a stabilizing device

[0209] S20 sintering layer application step

[0210] S30 pre-drying step

[0211] S40 placing step

[0212] S50 transferring step

[0213] S60 curing step

Claims

1. A method for sintering an interface surface (31) between an attachment object (30) and an attachment side (11) of a base part (10), the method comprising the steps of: • applying a sintering layer (20) onto the attachment side (11); • providing a stabilizing device (32) on the interface surface (31); • placing the attachment object (30) directly onto the sintering layer (20), wherein the interface surface (31) faces the sintering layer (20), and wherein the stabilizing device (32) protrudes into the sintering layer (20) for stabilizing a lateral position of the attachment object (30) relative to the base part (10), thereby forming a fitting (50) to be sintered; and a solidification step (S60) for solidifying the sintering layer (20) in the fitting (50) to be sintered, characterized in that the stabilizing device (32) is at least partially permanently compressed in the solidification step (S60).

2. The method of claim 1, wherein, The stabilizing device comprises at least one protrusion (32) protruding from the interface surface (31).

3. The method of claim 2, wherein, The stabilizing device comprises at least two protrusions (32) protruding from the interface surface (31), wherein the at least two protrusions (32) are spaced apart from each other.

4. The method of claim 3, wherein, The stabilizing device comprises a plurality of protrusions (32) protruding from the interface surface (31), the plurality of protrusions being arranged along a circumferential outer portion (31a) of the interface surface (31).

5. The method according to any one of claims 1 to 4, characterized in that, At least some of the stabilizing device (32) is formed on the interface surface (31) by a wire bonder.

6. The method of claim 5, wherein, The stabilizing device (32) comprises at least one wire bonding structure.

7. The method according to any one of claims 1 to 4, characterized in that, A step of inserting the fitting (50) to be sintered into a pressure sintering tool, wherein the attachment object (30) is placed onto the sintering layer (20) before the fitting (50) to be sintered is inserted into the pressure sintering tool.

8. The method according to any one of claims 1 to 4, characterized in that, The solidification step (S60) comprises sintering the sintering layer (20) with a maximum sintering temperature in a range of 200°C to 300°C and / or with a highest sintering pressure in a range of 10 MPa to 40 MPa.

9. The method according to any one of claims 1 to 4, characterized in that, The stabilizing device (32) is made of a material different from a material of the interface surface (31).

10. The method according to any one of claims 1 to 4, characterized in that, The attachment object is or comprises a heat generating component (30, 35, 37, 38, 39).

11. The method according to any one of claims 1 to 4, characterized in that, The attachment object is or comprises an electronic component (30, 37).

12. The method according to any one of claims 1 to 4, characterized in that, The attachment object is or comprises a semiconductor power module (30).

13. The method according to any one of claims 1 to 4, characterized in that, The base part (10) is a heat dissipater.

14. The method according to any one of claims 1 to 4, characterized in that, The base part (10) is a cooler.

15. The method according to any one of claims 1 to 4, characterized in that, The base part (10) is a heat sink.

16. The method of any one of claims 1 to 4, wherein, The attachment side (11) of the base part (10) is made of metal, and / or the interface surface (31) is made of metal.

17. An assembly (60) comprising a base part (10) and an attached object (30), wherein, A sintering layer (20a) between an interface surface (31) of an attachment object (30) and an attachment side (11) of a base part (10) fixes the attachment object (30) to the base part (10), wherein the assembly (60) has been formed by pressure sintering from a kit (50) to be sintered, the kit comprising the base part (10), the attachment object (30), and a sinter layer (20) arranged between the attachment side (11) and the interface surface, and further and a stabilizing device (32) formed on the interface surface (31) for stabilizing the lateral position of the attachment object (30) relative to the base part (10), wherein the stabilizing device protrudes into the sinter layer (20) in the kit (50) to be sintered for stabilizing the lateral position of the attachment object (30) relative to the base part (10), wherein the sinter layer (20) has been converted into a sinter body layer (20a) in a solidification step (S60), wherein in the assembly (60) the stabilizing device (32) formed at the interface surface (31) or at at least a remaining portion (32a) of the stabilizing device (32) protrudes into the sinter body layer (20a), wherein the attachment object (30) is a semiconductor power module (30) and comprises an integrated heat sink (33) arranged at the interface surface (31) of the attachment object (30), characterized in that the material of the stabilizing device (32) is softer than the material of the integrated heat sink (33) and the material of the base part (10) at the attachment side (11), and that the stabilizing device (32) has been at least partially permanently compressed in the solidification step (S60).

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