Assembly including a soldering spacer

Abstract

The invention relates to a brazing spacer (50) comprising: a perforated structure (10) including: a first perforated face (11) configured to be brazed to a first assembly face (2) of a first component (1), a second perforated face (12) configured to be brazed to a second assembly face (4) of a second component (3), the first perforated face (11) and the second perforated face (12) comprising openings (14) configured to allow the first perforated face (11) and second perforated face (12) to be deformed to accompany a deformation, respectively, of the first assembly face (2) and the second assembly face (4), a flexible thermal interface material (16) present within the perforated structure (10) to ensure thermal continuity between the first assembly face (2) of the first component (1) and the second assembly face (4) of the second component (3). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Assembly comprising a brazing interlayer

[0001] The present invention relates in particular to an assembly, in particular for integration into an electronic device, comprising a soldering interlayer.

[0002] Generally speaking, power electronic devices such as DC-AC converters (or inverters), DC-DC converters, and on-board chargers contain electronic components that have significant cooling requirements. This is the case, for example, with power modules (or "Power Modules") which include SiC chips that generate a considerable amount of heat during operation (for example, on the order of 80-100 W / cm²). To dissipate this heat, power modules (of the IGBT, switching cell, or other type) are mounted on dedicated heat sinks (or "Coolers"), for example, made of aluminum. This mounting is most often achieved using a thermal interface material (TIM) or by brazing / sintering.

[0003] The solution with thermal interface material or TIM (including a thermal cushion also called "Gap pad", thermal grease, or a filling material also called "Gap filler") presents high thermal contact resistances at the interfaces and does not ensure mechanical support.

[0004] The brazing / sintering solution, on the other hand, is very thermally efficient, but its reliability in thermal cycling is low due to differential thermal expansion stresses (differences in the coefficient of thermal expansion at the interfaces), which can generate cracks at the interfaces. Indeed, electronic chips have a silicon-based substrate with a very low coefficient of thermal expansion, and when the substrate is brazed onto an aluminum heat sink with a very high coefficient of thermal expansion, deformations can occur, leading to breakage in the substrate of the electronic components.

[0005] The invention aims in particular to provide an assembly which at least partially overcomes the aforementioned disadvantages.

[0006] The present invention relates to a soldering interlayer comprising: - an openwork structure comprising: • a first perforated face configured to be brazed to a first assembly face of a first component, • a second perforated face configured to be brazed to a second assembly face of a second component, • the first openwork face and the second openwork face comprising openings which are configured, in particular with a predetermined number of openings and / or dimensions of openings and / or distribution of openings, to allow the first openwork face and second openwork face to be deformed to accompany a deformation, in particular following thermal expansion, respectively of the first assembly face and the second assembly face, - a thermal interface material, preferably flexible, present within the openwork structure to ensure thermal continuity between the first assembly face of the first component and the second assembly face of the second component.

[0007] The invention prevents damage or breakage at the soldering interfaces that would result from differential deformations due to significantly different coefficients of thermal expansion at the soldering interfaces. Indeed, the perforated structure, with its adapted perforations, accommodates differential deformations, for example, between the first component, which comprises a silicon-based substrate, and a second component, which is a heat sink made of a metallic material, such as aluminum, or a metallic track. The perforated structure thus mechanically decouples the assembly faces of the first and second components while ensuring the assembly of these assembly faces during soldering and providing flexibility to the two solder joints thus formed thanks to the perforations.The openwork structure also allows, in the event of a crack due for example to excessive differential expansion, to limit the propagation of this crack and to isolate it thanks to the openwork configuration.

[0008] The thermal interface material, preferably flexible, ensures good thermal contact, allowing heat transfer from one component to the other. The flexible thermal interface material also provides flexibility to the interface, enabling it to withstand potential deformations during thermal cycles (tension, compression, shear of the interface).

[0009] According to one aspect of the invention, the first openwork face and the second openwork face of the openwork structure are in the form of a grid, in particular a metallic grid, for example in copper or aluminum.

[0010] Thus the openings of the first openwork face and the second openwork face are formed by the free spaces between the material lines of the grid.

[0011] In the event of deformation of the component, the grid brazed to the associated component can deform without breaking. For example, one material line of the grid may break, but the grid remains securely bonded to the assembly face of the associated component by the other lines. The grid's material lines prevent breakage from propagating throughout the openwork structure, thus improving its overall durability.

[0012] According to one aspect of the invention, the grid is made of a material having a coefficient of thermal expansion which is between the coefficient of thermal expansion of the first assembly face of the first component and the coefficient of thermal expansion of the second assembly face of the second component.

[0013] According to one aspect of the invention, the grid is made of a material having a coefficient of thermal expansion which is midway between the coefficient of thermal expansion of the first assembly face of the first component and the coefficient of thermal expansion of the second assembly face of the second component.

[0014] This makes it possible to avoid having a more fragile interface on one side of the brazing spacer than on the other, and to obtain a good balance between the deformations on both sides.

[0015] According to one aspect of the invention, the grid is made of a material selected from a metal or a metal alloy, in particular selected from the following list: - Nb: Niobium - Cr: Chrome - Mo: Molybdenum - W: Tungsten - Ta: Tantalus - a FeNi type alloy.

[0016] For the FeNi type alloy, the coefficient of thermal expansion (also called CTE for "Coefficient of Thermal Expansion" in English) depends strongly on the Ni (Nickel) content.

[0017] The FeNi alloy is a particularly interesting alloy because its coefficient of thermal expansion can be adjusted according to the proportion of nickel.

[0018] According to one aspect of the invention, the grid is made of expanded metal.

[0019] According to one aspect of the invention, the grid comprises meshes substantially made of diamond, rectangle, oval or other shapes.

[0020] According to one aspect of the invention, the meshes have characteristic dimensions, for example the largest dimension of the mesh, between 0.1 mm and 3 mm.

[0021] According to one aspect of the invention, the grid comprises substantially diamond-shaped meshes, and the diamond has a large diagonal of between 0.3 mm and 2.5 mm (for example 2.5 mm), and a small diagonal of between 0.2 mm and 1.6 mm (for example 0.2 mm).

[0022] According to one aspect of the invention, the grid has a thickness of substantially between 0.05 mm and 0.5 mm (being for example 0.1 mm).

[0023] The meshes can be arranged in a regular or irregular manner, for example in a random arrangement.

[0024] According to one aspect of the invention, the grid on one of the assembly faces of one of the components comprises a clear area that is free of mesh, obtained for example by cutting out the grid. This clear area is, for example, in the middle of the grid.

[0025] According to one aspect of the invention, the first openwork face and the second openwork face are parallel to each other.

[0026] According to one aspect of the invention, the perforated structure has a 3D shape, namely a shape whose dimensions in the three spatial directions are greater than the simple thickness of the material of the perforated structure, unlike, for example, a simple flat plate. The 3D shape is, for example, a parallelepiped, a cylinder, or a frustoconical shape.

[0027] According to one aspect of the invention, the openwork structure comprises a side wall connecting the first openwork face and the second openwork face of the openwork structure.

[0028] According to one aspect of the invention, the side wall has a polygonal perimeter, for example rectangular, or a rounded perimeter, in particular a circular perimeter.

[0029] According to one aspect of the invention, the openwork structure has a cobblestone shape, or a frustoconical shape or a truncated pyramid shape.

[0030] According to one aspect of the invention, the side wall of the openwork structure is in the form of a grid, in particular a metal grid.

[0031] Thus, the openwork structure can be made entirely of grid.

[0032] According to one aspect of the invention, the flexible thermal interface material is silicone-based, optionally with a ceramic or metallic filler.

[0033] According to one aspect of the invention, the flexible thermal interface material comprises a thermal cushion, also called a "Gap pad" in English.

[0034] In this case, we can start with a pre-formed thermal cushion and assemble the openwork structure on top of it, before carrying out the brazing.

[0035] Alternatively, the flexible thermal interface material includes a filling material, also called "Gap filler" in English.

[0036] In this case, the filler material can be poured onto the perforated structure already brazed to the components, and the filler material will polymerize. Pouring the material after brazing prevents disruption of the brazing contacts.

[0037] According to one aspect of the invention, particularly for high-temperature applications, the thermal interface material can be based on laminated expanded graphite, for example in the form of a flexible graphite sheet. This type of material exhibits resistance to high temperatures.

[0038] According to one aspect of the invention, the openwork structure envelops the thermal interface material.

[0039] According to one aspect of the invention, the openwork structure is obtained by folding an initially flat grid.

[0040] According to one aspect of the invention, the openwork structure has folded edges in the middle of the openwork structure.

[0041] According to one aspect of the invention, the folded edges of the openwork structure in the middle of the openwork structure are in contact together.

[0042] The openwork structure is notably different from a solid plate with a hole in the middle.

[0043] The invention further relates to an assembly, in particular for integration into an electronic device, this assembly comprising: - a first component comprising a first assembly face exhibiting a first coefficient of thermal expansion, - a second component comprising a second assembly face having a second coefficient of thermal expansion different from the first coefficient of thermal expansion, - an openwork structure comprising: • a first perforated face brazed to the first assembly face of the first component, • a second perforated face brazed to the second assembly face of the second component, • the first perforated face and the second perforated face comprising openings which are configured, in particular with a predetermined number of openings and / or dimensions of openings and / or distribution of openings, to allow the first perforated face and second perforated face to be deformed to accommodate a deformation, in particular following thermal expansion, respectively of the first assembly face and the second assembly face, - a thermal interface material, preferably flexible, present within the perforated structure to ensure thermal continuity between the first assembly face of the first component and the second assembly face of the second component, - the perforated structure with the thermal interface material defining a brazing spacer between the first component and the second component.

[0044] According to one aspect of the invention, the brazing of the perforated structure with the first and second components is carried out by soft soldering, preferably using a brazing alloy having a melting point below 250 °C. It can For example, it might be composed of a mixture of tin, silver, and copper. It's worth noting that soft soldering is soldering at a lower melting point than the metals of the first and second components. Furthermore, soft soldering can be done in a furnace or on an ad-hoc basis, using a blowtorch, soldering lamp, or induction heating, for example.

[0045] The present invention can be applied to the cooling of various types of electronic devices. For example, the first component and the second component are part of a battery cooling system, or of an electronic device such as a DC-AC converter, a DC-DC converter, or an on-board charger.

[0046] According to one aspect of the invention, the first component comprises a substrate made of silicon-based material and a second component which is a cooler made of metallic material, for example aluminum.

[0047] For example, the substrate is made of a stack of three layers: - a thin layer of copper on which the chips are assembled (by sintering, brazing for example), - a thicker layer of ceramic (AIN or A12O3 for example), - a final thin layer of copper.

[0048] According to another embodiment of the invention, the first component comprises a base plate (or "base plate" in English), in particular made of copper, and a second component which is a cooler made of metallic material, for example aluminum.

[0049] In this case, the openwork structure can be made of nickel (Ni), copper (Cu), cobalt (Co) or iron-nickel alloy (FeNi).

[0050] According to another embodiment of the invention, the base plate carries a substrate made of silicon-based material. The first component comprises, for example, one or more electronic chips placed on the substrate.

[0051] The present invention further relates to a method for manufacturing an assembly as described above, comprising the following steps: - Place the openwork structure between the first component and the second component. - braze the openwork structure with the first component and the second component, in particular by soft brazing, preferably using a brazing alloy having a melting point below 250 °C, for example composed of a mixture of tin, silver and copper.

[0052] According to one aspect of the invention, the flexible thermal interface material comprises a thermal cushion, also called a "Gap pad" in English.

[0053] In this case, the process comprises the following steps: - providing a pre-formed thermal cushion, - assemble the openwork structure onto the already formed thermal cushion, before carrying out the brazing.

[0054] In this case, the brazing spacer can be a single piece, before being placed in the assembly.

[0055] Alternatively, the flexible thermal interface material includes a filling material, also called "Gap filler" in English.

[0056] In this case, the process comprises the following step: - pour the filling material onto the openwork structure already brazed to the components.

[0057] According to one aspect of the invention, the filler material polymerizes following deposition. Pouring the material after brazing prevents disruption of the brazing contacts.

[0058] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0059] [Fig. 1] The [Fig. 1] is a perspective representation of an example of an embodiment of an assembly according to the invention, configured to be integrated into an electronic device;

[0060] [Fig.2] Fig.2 is a perspective representation of an openwork structure of the whole of [Fig.1];

[0061] [Fig.3] Fig.3 is a perspective representation of an openwork structure according to another example of the realization of the invention;

[0062] [Fig.4] Fig.4 is a side view representation of an openwork structure according to yet another example of the realization of the invention;

[0063] [Fig. 5] Fig. 5 is a cross-sectional representation of an electronic device with a set of the [Fig.l];

[0064] [Fig. 6] Fig. 6 is a cross-sectional representation of another electronic device with a set of the [Fig.l];

[0065] [Fig.7] Fig.7 represents a curve which shows that the coefficient of expansion thermal activity depends on the Ni (Nickel) content;

[0066] [Fig.8] Fig.8 shows examples of grids with meshes of various shapes.

[0067] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, which will be described hereafter in isolation from the others. characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0068] In the following description, identical elements or elements with identical function bear the same reference numeral. For the sake of brevity, only the differences between the embodiments presented are described.

[0069] Figure [Fig.1] shows an assembly 100 configured to be integrated into an electronic device 200.

[0070] The first component 1 and the second component 3 are part of a battery cooling system, or of an electronic device 200 such as a DC-AC converter, a DC-DC converter, an on-board charger

[0071] This assembly 100 comprises a first component 1 including a first assembly face 2 having a first coefficient of thermal expansion, and a second component 3 including a second assembly face 4 having a second coefficient of thermal expansion different from the first coefficient of thermal expansion.

[0072] The assembly 100 further comprises an openwork structure 10 comprising: - a first perforated face 11 brazed to the first assembly face 2 of the first component 1, - a second perforated face 12 brazed to the second assembly face 4 of the second component 3, - the first openwork face 11 and the second openwork face 12 comprising openings 14 which are configured, in particular with a number of openings 14 and / or dimensions of openings 14 and / or a distribution of openings 14 predetermined, to allow the first openwork face 11 and second openwork face 12 to be deformed to accompany a deformation, following a thermal expansion, respectively of the first assembly face 2 and the second assembly face 4.

[0073] A flexible thermal interface material 16 is present within the openwork structure 10 to ensure thermal continuity between the first assembly face 2 of the first component 1 and the second assembly face 4 of the second component 3,

[0074] The openwork structure 10 with the thermal interface material 16 defines a brazing spacer 50 between the first component 1 and the second component 3, as will be seen later.

[0075] The flexible thermal interface material 16 ensures good thermal contact, allowing heat to be transferred from one component to the other. The flexible thermal interface material 16 also provides flexibility to the interface. to allow it to withstand potential deformations during thermal cycles (tension, compression, shear of the interface).

[0076] As can be seen in [Fig.2], the first openwork face 11 and the second openwork face 12 of the openwork structure 10 are faces of a metal grid 17, for example made of copper or aluminum, as further described below.

[0077] Thus the openings 14 of the first openwork face 11 and the second openwork face 12 are formed by the free spaces between the material lines of the grid 17.

[0078] In the event of deformation of component 1 or 3, the grid 17 brazed to the associated component 1 or 3 can deform without breaking. For example, one material line of the grid 17 may break, but the grid remains securely bonded to the assembly face of the associated component 1 or 3 by the other material lines of the grid 17. The break does not propagate throughout the entire perforated structure 10. This improves the durability of the assembly 100.

[0079] The grid 17 is made of a material having a coefficient of thermal expansion which is between the coefficient of thermal expansion of the first assembly face 2 of the first component 1 and the coefficient of thermal expansion of the second assembly face 4 of the second component 3. For example, the grid 17 is made of a material having a coefficient of thermal expansion which is midway between the coefficient of thermal expansion of the first assembly face 2 of the first component 1 and the coefficient of thermal expansion of the second assembly face 4 of the second component 3.

[0080] This makes it possible to avoid having a more fragile interface on one side of the brazing spacer than on the other, and to obtain a good balance between the deformations on both sides.

[0081] According to one aspect of the invention, the grid 17 is made of a material selected from a metal or a metal alloy, in particular selected from the following list: - Note: Niobium - Cr: Chrome - Mo: Molybdenum - W: Tungsten - Ta: Tantalus - a FeNi type alloy.

[0082] For the FeNi type alloy, the coefficient of thermal expansion (also called CTE for "Coefficient of Thermal Expansion" in English) depends strongly on the Ni (Nickel) content, as illustrated in the curve of [Fig.7].

[0083] On this graph of [Fig.7], the x-axis represents the Ni (Nickel) content relative to the Iron content, and the y-axis represents the coefficient of thermal expansion (in units of 10⁶ K*).

[0084] The FeNi alloy is a particularly interesting alloy because its coefficient of thermal expansion can be adjusted according to the proportion of nickel.

[0085] As illustrated in [Fig.8], the grid 17 comprises meshes 18 substantially in diamond, rectangle, oval or other shapes.

[0086] The meshes have characteristic dimensions, for example the largest dimension of the mesh, between 0.1 mm and 3 mm.

[0087] For example, on the grid example on the left in [Fig.8], the grid 17 comprises meshes 18 substantially in the shape of a rhombus, and the rhombus has a large diagonal GD between 0.3 mm and 2.5 mm (for example 2.5 mm), and a small diagonal PD between 0.2 mm and 1.6 mm (for example 0.2 mm).

[0088] According to one aspect of the invention, the grid 17 has a thickness EP of substantially between 0.05 mm and 0.5 mm (being for example 0.1 mm).

[0089] The meshes 18 can be arranged in a regular or irregular manner, for example in a random arrangement.

[0090] In an unillustrated variant, the grid 17 on one of the assembly faces of one of the components includes a clear area which is devoid of mesh, obtained for example by cutting the grid 17. This clear area is for example in the middle of the grid 17.

[0091] In the example of Figures 1 and 2, the first perforated face 11 and the second perforated face 12 are parallel to each other. Here, the perforated structure 10 has a 3D shape, namely a shape whose dimensions in the three spatial directions are greater than the simple thickness of the material of the perforated structure 10, unlike, for example, a simple flat plate. The 3D shape is a parallelepiped, here a rectangular prism, in the example of Figures 1 and 2.

[0092] Thus, the openwork structure 10 comprises parallel side walls 19 connecting the first openwork face 11 and the second openwork face 12 of the openwork structure 10.

[0093] Each side wall 19 has a rectangular perimeter.

[0094] The grid 17 is pounded to give the cobblestone shape.

[0095] In the example of figures 1 and 2, the first openwork face 11 and the second openwork face 12 both cover the entire extent between the opposite side walls 19.

[0096] Alternatively, as illustrated in [Fig. 3], the second openwork face 12 covers only part of the area between the opposite side walls 19. For example, the second openwork face 12 is interrupted in the middle, with two free edges of the grid 17.

[0097] The openwork structure 10 is obtained by folding an initially flat grid 17.

[0098] In another example illustrated in [Fig.4], the openwork structure 10 has folded edges 21 in the middle of the openwork structure 10.

[0099] The folded edges 21 of the openwork structure 10 in the middle of the openwork structure 10, are spaced apart from each other, or alternatively, in contact with each other.

[0100] In the example described, the flexible thermal interface material 16 is silicone-based, optionally with a ceramic or metallic filler.

[0101] In the example of [Fig.3], the flexible thermal interface material 16 includes a thermal cushion 20, also called a "Gap pad" in English.

[0102] In this case, we can start from a thermal cushion 20 already formed and assemble the openwork structure 10 on top of it, before carrying out the brazing.

[0103] Alternatively, the flexible thermal interface material 16 includes a filling material, also called "Gap filler" in English.

[0104] In this case, the filler material can be poured / injected onto the perforated structure 10, which has already been brazed to components 1 and 3, and the filler material will polymerize. Pouring the material after brazing prevents disruption of the brazing contacts.

[0105] According to one aspect of the invention, particularly for high-temperature applications, the thermal interface material 16 can be based on laminated expanded graphite, for example in the form of a flexible graphite sheet. This type of material exhibits resistance to high temperatures.

[0106] In general, the openwork structure 10 envelops the thermal interface material 16.

[0107] In the example described, the brazing of the openwork structure 10 with the first and second components is carried out by soft soldering, preferably using a solder alloy with a melting point below 250 °C. It may, for example, be composed of a mixture of tin, silver, and copper. It should be noted that soft soldering is soldering at a lower melting temperature than that of the metals of the first and second components. Furthermore, soft soldering can be carried out in a furnace or on an ad hoc basis, for example, using a blowtorch, soldering lamp, or induction heating.

[0108] In the example illustrated in [Fig. 5], the first component 1 comprises a substrate 30 made of silicon-based material (which carries power electronic components, for example) and a second component 3, which is a heat sink 40 made of metallic material, for example, aluminum. According to another embodiment of the invention, the base plate carries a substrate made of silicon-based material. The first component 1 carries, for example, one or more electronic chips placed on the substrate.

[0109] For example, substrate 30 is made of a stack of three layers: - a thin layer of copper on which the chips are assembled (by sintering, brazing for example), - a thicker layer of ceramic (AIN or A12O3 for example), - a final thin layer of copper.

[0110] Such a substrate 30 is called a DBC substrate (for "direct bonding copper").

[0111] The soldering spacer 50 is placed between the substrate 30 and the cooler 40.

[0112] According to another embodiment of the invention illustrated in [Fig.6], the first component 1 comprises a base plate 60 (or "base plate" in English), in particular made of copper, which serves as a mechanical support for an electronic card, and a second component 3 which is a heat sink 40 made of metallic material, for example aluminum.

[0113] In this case, the openwork structure 10 can be made of nickel (Ni), copper (Cu), cobalt (Co) or iron-nickel alloy (FeNi).

[0114] In the invention, the method for manufacturing an assembly 100 as described above comprises the following steps: - place the openwork structure 10 between the first component 1 and the second component 3, - braze the openwork structure 10 with the first component 1 and the second component 3, in particular by soft brazing, preferably using a brazing alloy having a melting point below 250 °C, for example composed of a mixture of tin, silver and copper.

[0115] According to one aspect of the invention, the flexible thermal interface material comprises a thermal cushion 20, also called a "Gap pad" in English.

[0116] In this case, the process comprises the following steps: - provide a pre-formed thermal cushion, - assemble the openwork structure 10 onto the already formed thermal cushion, before carrying out the brazing.

[0117] In this case, the brazing spacer 50 can be a single piece, before its placement in the assembly 100.

[0118] Alternatively, the flexible thermal interface material includes a filling material, also called "Gap filler" in English.

[0119] In this case, the process comprises the following step: - pour the filling material onto the openwork structure 10 already brazed to the components.

[0120] According to one aspect of the invention, the filler material polymerizes following deposition. Pouring the material after brazing prevents disruption of the brazing contacts.

Claims

Demands

1. A brazing spacer (50) comprising: - a perforated structure (10) including: • a first perforated face (11) configured to be brazed to a first assembly face (2) of a first component (1), • a second perforated face (12) configured to be brazed to a second assembly face (4) of a second component (3), • the first perforated face (11) and the second perforated face (12) comprising perforations (14) which are configured, in particular with a predetermined number of perforations (14) and / or perforation dimensions (14) and / or perforation distribution (14), to allow the first perforated face (11) and second perforated face (12) to be deformed to accommodate a deformation, in particular following thermal expansion, of the first assembly face (2) and the second assembly face (4), respectively, - a material thermal interface (16), preferably flexible,present within the openwork structure (10) to ensure thermal continuity between the first assembly face (2) of the first component (1) and the second assembly face (4) of the second component (3).

2. Brazing spacer (50) according to the preceding claim, wherein the first openwork face (11) and the second openwork face (12) of the openwork structure (10) are in the form of a grid (17), in particular a metallic grid (17), for example made of copper or aluminum.

3. A brazing spacer (50) according to any one of the preceding claims, wherein the grid (17) is made of a material selected from a metal or a metal alloy, in particular selected from the following list: - Nb: Niobium - Cr: Chromium - Mo: Molybdenum - W: Tungsten - Ta: Tantalum - an FeNi type alloy.

4. Soldering spacer (50) according to any one of the preceding claims, wherein the grid (17) comprises meshes (18) substantially in diamond, rectangle, oval or other shapes.

5. Brazing spacer (50) according to any one of the preceding claims, wherein the perforated structure (10) has folded edges (21) in the middle of the perforated structure (10), and the folded edges (21) of the perforated structure (10) in the middle of the perforated structure (10) are in contact together (100).

6. Assembly (100), in particular for integration into an electronic device (200), said assembly (100) comprising: - a first component (1) comprising a first assembly face (2) having a first coefficient of thermal expansion, - a second component (3) comprising a second assembly face (4) having a second coefficient of thermal expansion different from the first coefficient of thermal expansion, - a perforated structure (10) comprising: • a first perforated face (11) brazed to the first assembly face (2) of the first component (1), • a second perforated face (12) brazed to the second assembly face (4) of the second component (3), • the first perforated face (11) and the second perforated face (12) comprising perforations (14) which are configured, in particular with a number of perforations (14) and / or perforation dimensions (14) and / or a perforation distribution (14) predetermined,to allow the first perforated face (11) and second perforated face (12) to be deformed to accommodate a deformation, in particular following thermal expansion, respectively of the, first assembly face (2) and second assembly face (4), - a thermal interface material (16), preferably flexible, present within the openwork structure (10) to ensure thermal continuity between the first assembly face (2) of the first component (1) and the second assembly face (4) of the second component (3), - the openwork structure (10) with the thermal interface material (16) defining a brazing spacer (50) between the first component (1) and the second component (3).

7. Assembly (100) according to the preceding claim, wherein the grid (17) is made of a material having a coefficient of thermal expansion which is between the coefficient of thermal expansion of the first assembly face (2) of the first component (1) and the coefficient of thermal expansion of the second assembly face (4) of the second component (3).

8. A method for manufacturing an assembly (100) as described above, comprising the following steps: - placing the openwork structure (10) between the first component (1) and the second component (3), - brazing the openwork structure (10) with the first component (1) and the second component (3), in particular by soft brazing, preferably using a brazing alloy having a melting point below 250 °C, for example composed of a mixture of tin, silver and copper.

9. A method according to the preceding claim, wherein the flexible thermal interface material (16) comprises a thermal pad (20), and the method comprises the following steps: - providing a pre-formed thermal pad (20), - assembling the perforated structure (10) onto the pre-formed thermal pad (20), before carrying out the brazing.

10. A method according to claim 8, wherein the flexible thermal interface material (16) comprises a filling material, and the method comprises the following step: pour the filling material onto the openwork structure (10) already brazed to the components.

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