Electronic circuit board comprising a structured external surface

Abstract

Electronic board (1) comprising, in a stack: at least one power stage (2) having at least one electronic component (5) placed integrated within the electronic board (1), at least one heat dissipation stage (6) placed in thermal contact with at least one face of a power stage (2) and arranged to dissipate the heat generated by the power stage (2), characterized in that the heat dissipation stage (6) has a structured external surface (10) forming a thermal interface with an external medium (11) and having a heat exchange area at least 20% larger than the area of ​​the projection onto a flat surface of this structured external surface (10). Figure for the abstract: Figure 1

Description

Title of the invention: Electronic circuit board comprising a structured external surface Scope of the invention

[0001] The field of the invention is that of the thermal management of electronic components. State of the art

[0002] Electronic boards comprising integrated electronic components are known.

[0003] The use of integrated electronic components requires good dissipation of the heat generated by these components to allow proper operation.

[0004] Effective thermal management is crucial to minimize losses, improve reliability and avoid high temperature-related failures.

[0005] The invention aims to provide improved electronics integration solutions by improving the dissipation of heat generated by electronic components. Description of the invention

[0006] The invention relates to an electronic card comprising, in a stack: - at least one power stage comprising at least one electronic component integrated within the electronic board, - at least one heat dissipation stage placed in thermal contact with at least one face of a power stage and arranged to dissipate the heat generated by the power stage, characterized in that the heat dissipation stage has a structured external surface forming a thermal interface with an external environment and having an exchange area at least 20% higher than the area of ​​the projection onto a flat surface of this structured external surface.

[0007] According to one aspect of the invention, the structured external surface has an exchange area at least 30% higher than the area of ​​the projection on a flat surface of this structured external surface, in particular at least 50% higher, in particular 100% higher.

[0008] According to one aspect of the invention, the exchange area is the geometric shape of the structured external surface measured taking into account the reliefs that form the structured surface.

[0009] According to one aspect of the invention, the structured external surface has reliefs arranged to increase the exchange area.

[0010] According to one aspect of the invention, the reliefs are, for example:

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] - small bumps, particularly cylindrical ones, - straight or cylindrical grooves, - rafters, Alternatively, the reliefs can be of any other shape, and can be of random shape. In the embodiment where the reliefs are cylindrical studs, the exchange surface area is equal to the sum: - the surface area between the studs, - the surfaces of the cylindrical faces of the studs, - the surface areas of the bases of the spikes. According to one aspect of the invention, the ratio between the exchange area and the area of ​​the projection on a flat surface of this structured external surface then depends on factors such as the number of studs, their diameter, their height, or their spacing. According to one aspect of the invention, the reliefs of the external surface have a thickness of between 1 and 5,000 micrometers, in particular between 100 and 1,000 micrometers. According to one aspect of the invention, the structured external surface is arranged to be placed in heat exchange with an external environment. According to one aspect of the invention, the structured external surface is integrated into the electronic board and is formed by an external layer of a heat dissipation stage of the electronic board. According to one aspect of the invention, the structured external surface is manufactured in the same process as the power stage and in particular as the electronic board. In particular, the structured external surface is not a separate part added to the electronic board. According to one aspect of the invention, the reliefs of the structured external surface are produced by machining. Alternatively, the reliefs of the structured external surface can be achieved by any other method, including additive manufacturing. According to one aspect of the invention, the structured external surface is made of copper. Alternatively, the structured external surface can be made with any other material, for example aluminium. According to one aspect of the invention, the electronic component is substantially planar in shape. According to one aspect of the invention, the power stage includes a connection layer placed in contact with one face of the electronic component.

[0025] According to one aspect of the invention, the connection layer comprises: - a substrate placed in contact with the face of the electronic component, - at least one electronic track placed on the substrate, in particular on the face of the substrate opposite to the electronic component, - at least one via passing through the substrate and electrically connecting the electronic component to at least one electronic trace of the connection layer.

[0026] According to one aspect of the invention, the connecting layer has a thickness between 20 micrometers and 100.

[0027] According to one aspect of the invention, at least one via is a solid copper via.

[0028] According to one aspect of the invention, the face of the substrate bearing the tracks forms a first side of the power stage.

[0029] According to one aspect of the invention, the power stage comprises a first sintering layer placed in contact with a face of the electronic board, in particular in contact with the face of the electronic component opposite to the connection layer.

[0030] According to one aspect of the invention, the face of the first sintering layer opposite the face of the first sintering layer in contact with which the electronic component is placed forms a second face of the power stage.

[0031] According to one aspect of the invention, the electronic component includes a thermal base, arranged to promote the transfer of heat dissipated by the electronic component to a thermal dissipation stage.

[0032] According to one aspect of the invention, the first sintering layer comprises at least one thermal pad placed in contact with the thermal pad of the electronic component, and arranged to conduct the heat dissipated by the electronic component to a thermal dissipation stage.

[0033] According to one aspect of the invention, the first sintering layer has a thickness of between 20 micrometers and 100 micrometers.

[0034] According to one aspect of the invention, the electronic component is intercalated between the first sintering layer and the connection layer.

[0035] According to one embodiment of the invention, the first face of the power stage is a heat dissipation surface, called first heat dissipation surface 3, and a heat dissipation stage called first heat dissipation stage, is placed in thermal contact with the first heat dissipation surface 3.

[0036] Alternatively or in addition, the second face of the power stage is a heat dissipation surface, called the second heat dissipation surface 4, and a heat dissipation stage called the second heat dissipation stage thermal, is placed in thermal contact with the second heat dissipation surface 4.

[0037] According to one aspect of heat dissipation, it comprises at least one copper insert placed in contact with the power stage, in particular placed in contact with the connection layer, or in contact with a thermal pad of the power stage.

[0038] According to one aspect of the invention, the copper insert is arranged to dissipate the heat generated by the power stage.

[0039] According to one aspect of the invention, the copper insert is inserted into a layer of the heat dissipation stage.

[0040] According to one aspect of the invention, the structured external surface is formed by an external surface of a copper insert.

[0041] According to one embodiment of the invention, the structured external surface is arranged to be placed in heat exchange with a dielectric fluid.

[0042] According to one embodiment of the invention, the structured external surface is arranged to be placed in heat exchange with a flow of glycolated water.

[0043] According to one aspect of the invention, the heat dissipation stage includes an insulating layer, arranged to electrically isolate the power stage from the glycol water flow, so as to protect the electronic component.

[0044] According to one aspect of the invention, the insulating layer is made of insulating material, in particular ceramic.

[0045] According to one aspect of the invention, the heat dissipation stage comprises two copper inserts, and the insulating layer is intercalated between the two copper inserts.

[0046] Advantageously, the use of a stack of an insulating layer and two copper inserts makes it possible to combine the heat dissipation properties of copper with the electrical protection provided by the insulating layer.

[0047] According to one aspect of the invention, a plurality of heat dissipation stages on at least one side of the power stage.

[0048] According to one aspect of the invention, the plurality of heat dissipation stages can be realized in the same way or with different embodiments.

[0049] According to one aspect of the invention, only the thermal dissipation stages placed in heat exchange with a glycol water flow include an insulating layer.

[0050] According to one aspect of the invention, the different heat dissipation stages are separated by intermediate sintering layers comprising thermal pads, arranged to promote heat transfer between the different heat dissipation stages.

[0051] Advantageously, stacking several heat dissipation stages improves the dissipation of heat generated by the power stage, particularly when the power stage is traversed by significant electrical currents.

[0052] According to one aspect of the invention, the external heat dissipation stages, placed in contact with an external environment, have a structured external surface forming a thermal interface with this external environment.

[0053] According to one aspect of the invention, the electronic board comprises two external heat dissipation stages, each comprising a structured external surface.

[0054] Alternatively, the electronic board has an external connection face on which surface electronic components are mounted.

[0055] According to one aspect of the invention, the surface electronic components are electrically connected to the electronic component integrated inside the electronic board.

[0056] According to one aspect of the invention, the electronic card then comprises - a single external heat dissipation stage comprising a single structured external surface, - an external connection face. List of figures

[0057] 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:

[0058] [Fig-1] Fig. 1 is a representation of an electronic card according to the invention, comprising two.

[0059] [Fig.2] Fig.2 is a representation of an electronic circuit board according to the invention in which the heat dissipation stages include insulating layers.

[0060] [Fig.3] Fig.3 is a representation of an electronic circuit board according to the invention comprising several superimposed thermal dissipation stages on one side of the power stage.

[0061] [Fig.4] Fig.4 is a representation of an electronic circuit board according to the invention comprising several superimposed thermal dissipation stages on each side of the power stage.

[0062] [Fig. 5] Fig. 5 is a representation of an electronic circuit board according to the invention including an external connection face.

[0063] [Fig.6] Fig.6 is a representation of an electronic circuit board according to the invention including an external connection face, several superimposed thermal dissipation stages on each side of the power stage.

[0064] The features, variations, and different embodiments of the invention can be combined with one another in various ways, provided they are not incompatible or mutually exclusive. In particular, variations of the invention may be imagined that do not include that a selection of features described subsequently in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art. Detailed description

[0065] Figure 1 shows an electronic card 1 according to the invention comprising, in a stack: - a power stage 2 comprising: • a first heat dissipation surface 3, • a second heat dissipation surface 4 • an electronic component 5 placed integrated inside the electronic board 1, - a first heat dissipation stage 6 placed in thermal contact with the first heat dissipation surface 3 of the power stage 2 and arranged to dissipate the heat generated by the power stage 2, - a second heat dissipation stage 7 placed in thermal contact with the second heat dissipation surface 4 of the power stage 2 and arranged to dissipate the heat generated by the power stage 2.

[0066] The first heat dissipation stage 6 and the second heat dissipation stage 7 are two external heat dissipation stages, each comprising a structured external surface 10 forming a thermal interface with an external medium 11.

[0067] These structured external surfaces 10 have an exchange area at least 20% higher than the area of ​​the projection onto a flat surface of this structured external surface 10.

[0068] Embodiments of a structured external surface 10 are described below. The two structured external surfaces 10 can be made with identical or distinct embodiments.

[0069] According to one aspect of the invention, the structured external surface 10 has an exchange area at least 30% higher than the area of ​​the projection on a flat surface of this structured external surface 10, in particular at least 50% higher, in particular 100% higher.

[0070] The exchange area is the geometric area of ​​the structured external surface 10 measured taking into account the reliefs that form the structured external surface 10.

[0071] The structured external surface 10 has reliefs 12 arranged to increase the exchange surface area, here straight grooves

[0072] Alternatively, the reliefs 12 may be of any other shape, for example, studs, in particular cylindrical ones, cylindrical grooves, chevrons, and may be of random shape.

[0073] In the embodiment where the reliefs are cylindrical studs, the exchange surface area is equal to the sum: - the surface area between the studs, - the surfaces of the cylindrical faces of the studs, - the surface areas of the bases of the spikes.

[0074] In the embodiment represented here, the exchange area is the sum of the area of ​​the surface between the grooves, the area of ​​the upper faces of the grooves, and the area of ​​the lateral faces of the grooves.

[0075] Advantageously, the use of reliefs makes it possible to increase the exchange surface and improve the thermal dissipation of the heat generated by the electronic component.

[0076] The reliefs 12 of the external surface have a thickness of between 1 and 5,000 micrometers, in particular between 100 and 1,000 micrometers.

[0077] The structured external surface 10 is arranged to be placed in heat exchange with an external environment 11.

[0078] The structured external surface 10 is integrated into the electronic board 1 and is formed by an external layer of a heat dissipation stage 6, 7 of the electronic board 1.

[0079] The structured external surface 10 is manufactured in the same process as the electronic board 1.

[0080] In particular, the structured external surface 10 is not a separate part added to the electronic board 1.

[0081] The reliefs of the structured external surface 10 are produced by machining.

[0082] Alternatively, the reliefs of the structured external surface 10 can be produced by any other method, in particular by additive manufacturing.

[0083] The structured external surface 10 is made of copper.

[0084] Alternatively, the structured external surface 10 can be made with any other material, for example aluminium.

[0085] The electronic component 5 is substantially planar in shape.

[0086] The power stage 2 includes a connection layer 15 placed in contact with one face of the electronic component 5, and comprising: - a substrate 17 placed in contact with the face of the electronic component 5, - at least one electronic trace placed on substrate 17, in particular on the face of substrate 17 opposite to electronic component 5, - at least one via 18, here four passing through the substrate and electrically connecting the electronic component 5 to the electronic tracks of the connection layer 15.

[0087] The connection layer 15 has a thickness between 20 micrometers and 100.

[0088] The vias 18 are solid copper vias.

[0089] The face of the substrate 17 bearing the tracks forms a first face of the power stage 2.

[0090] The power stage 2 includes a first sintering layer 16 placed in contact with the face of the electronic component 5 opposite the connection layer 15.

[0091] The face of the first sintering layer 16 opposite the face of the first sintering layer 16 in contact with which the electronic component 5 is placed forms a second face of the power stage 2.

[0092] The electronic component 5 includes a thermal base 20, arranged to promote the transfer of heat dissipated by the electronic component 5 to a thermal dissipation stage, here the first thermal dissipation stage 6.

[0093] The first sintering layer 16 has a thermal pad 21 placed in contact with the thermal pad 20 of the electronic component 5, and arranged to conduct the heat dissipated by the electronic component 5 to the first thermal dissipation stage 6.

[0094] The first sintering layer 16 has a thickness between 20 micrometers and 100 micrometers.

[0095] The electronic component 5 is intercalated between the first sintering layer 16 and the connection layer 15.

[0096] The heat dissipation stages 6, 7 each include a copper insert 25 placed in contact with the power stage 2.

[0097] In particular, the first heat dissipation stage 6 is placed in contact with a thermal pad of the power stage 2, and the second heat dissipation stage 7 is placed in contact with the connection layer 15.

[0098] The copper inserts 25 are arranged to dissipate the heat generated by the power stage 2, and are inserted into a layer of the first heat dissipation stage 6 and the second heat dissipation stage 7.

[0099] The two structured external surfaces 10 are formed by the external surfaces of the copper inserts 25.

[0100] In this embodiment of the invention, the structured external surfaces 10 are arranged to be placed in heat exchange with a dielectric fluid.

[0101] Figure 2 shows an electronic card 1 according to the invention in which the thermal dissipation stages 6, 7 comprise insulating layers 26.

[0102] In this embodiment, the structured external surfaces 10 are arranged to be placed in heat exchange with a flow of glycolated water.

[0103] The insulating layers 26 of the heat dissipation layers 6, 7 are arranged to electrically isolate the power stage 2 from the glycol water flow, so as to protect the electronic component 5.

[0104] The insulating layers 26 are made of insulating material, in particular ceramic.

[0105] The first heat dissipation stage 6 and the second heat dissipation stage 7 each comprise two copper inserts 25, and their insulating layers 26 are each intercalated between these two copper inserts.

[0106] Advantageously, the use of a stack of an insulating layer 26 and two copper inserts 25 makes it possible to combine the heat dissipation properties of copper with the electrical protection provided by the insulating layer.

[0107] Figure 3 shows an electronic board 1 according to the invention comprising several thermal dissipation stages, here two thermal dissipation stages 106a, 106b superimposed on one side of the power stage 2.

[0108] These heat dissipation stages 106a, 106b are here stacked on the side of the first sintering layer 16 of the power stage 2.

[0109] The plurality of heat dissipation stages can be realized in the same way or with different embodiments.

[0110] In particular, only the heat dissipation stage 106b placed in heat exchange with a glycol water flow has an insulating layer.

[0111] The heat dissipation stages are separated by an intermediate sintering layer 110 comprising a thermal pad 111, arranged to promote heat transfer between these heat dissipation stages 106a, 106b.

[0112] Only the external heat dissipation stages, placed in contact with an external environment, have a structured external surface 10 forming a thermal interface with this external environment.

[0113] Advantageously, stacking several heat dissipation stages 106a, 106b improves the dissipation of heat generated by the power stage 2, particularly when the power stage 2 is traversed by significant electrical currents.

[0114] Figure 4 shows an electronic card 1 according to the invention comprising several thermal dissipation stages 106a, 106b, 107a, 107b superimposed on each side of the power stage 2.

[0115] In this embodiment, the electronic card 1 is arranged to be placed in heat exchange with a flow of glycol water.

[0116] The external thermal dissipation stages 106b, 107b comprise an insulating layer 26, and a structured external surface 10 forming a thermal interface with this external environment.

[0117] Figure 5 shows an electronic card 1 according to the invention comprising an external connection face 200 on which surface electronic components 201 are mounted.

[0118] The surface electronic components 201 are electrically connected to the electronic component 5 integrated inside the electronic board 1.

[0119] The electronic card 1 in this embodiment comprises a single external thermal dissipation stage 206 having a single structured external surface 10, and an external connection face.

[0120] Figure 6 shows an electronic board 1 according to the invention comprising an external connection face and several thermal dissipation stages 206a, 206b superimposed on each side of the power stage 2.

Claims

Demands

1. Electronic board (1) comprising, in a stack: - at least one power stage (2) having at least one electronic component (5) placed integrated inside the electronic board (1), - at least one heat dissipation stage (6) placed in thermal contact with at least one face of a power stage (2) and arranged to dissipate the heat generated by the power stage (2), characterized in that the heat dissipation stage (6) has a structured external surface (10) forming a thermal interface with an external medium (11) and having an exchange area at least 20% higher than the area of ​​the projection onto a flat surface of this structured external surface (10).

2. Electronic card (1) according to claim 1, wherein the structured external surface (10) has reliefs (12) arranged to increase the exchange area.

3. Electronic board (1) according to any one of the preceding claims, wherein the structured external surface (10) is integrated into the electronic board (1) and is formed by an external layer of a heat dissipation stage (6) of the electronic board (1),

4. Electronic board (1) according to the preceding claim, wherein the structured external surface (10) is manufactured in the same process as the power stage (2).

5. Electronic card (1) according to any one of the preceding claims, wherein the structured external surface (10) is made of copper.

6. Electronic board (1) according to any one of the preceding claims, wherein the power stage (2) comprises a connection layer (15) placed in contact with a face of the electronic component (5), and comprising: - a substrate (17) placed in contact with the face of the electronic component (5), - at least one electronic trace placed on the substrate (17), in particular on the face of the substrate (17) opposite the electronic component (5), - at least one via (18) through the substrate (17) and electrically connecting the electronic component (5) to at least one electronic trace of the connection layer (15).

7. Electronic board (1) according to any one of the preceding claims, wherein the power stage (2) has a first sintering layer (16) placed in contact with a face of the electronic component (5).

8. Electronic board (1) according to any one of the preceding claims, wherein: - the electronic component (5) has a thermal pad (20), arranged to promote the transfer of heat dissipated by the electronic component (5) to a heat dissipation stage (6), - the first sintering layer (16) has at least one thermal pad (21) placed in contact with the thermal pad (20) of the electronic component (5), and arranged to conduct the heat dissipated by the electronic component (5) to a heat dissipation stage (6).

9. Electronic board (1) according to any one of the preceding claims, wherein the heat dissipation stage (6) includes at least one copper insert (25) placed in contact with the power stage (2), in particular placed in contact with the connection layer (15), or in contact with a thermal pad (21) of the power stage (2) and arranged to dissipate the heat generated by the power stage (2).

10. Electronic card (1) according to any one of the preceding claims, wherein the structured external surface (10) is arranged to be placed in heat exchange with a dielectric fluid or with a glycol water flow.

11. Electronic board (1) according to any one of the preceding claims, wherein the heat dissipation stage (6) includes an insulating layer (26), arranged to electrically isolate the power stage (2) so as to protect the electronic component (5).

12. Electronic board (1) according to any one of the preceding claims, wherein a plurality of heat dissipation stages (106a, 106b, 107a, 107b, 206a, 206b) are superimposed on at least one side of the power stage (2).

13. Electronic card according to one of the preceding, the electronic card (1) has two external heat dissipation stages (6, 7, 106b, 107b) each having a structured external surface (10).

14. Electronic card (1) according to any one of claims 1 to 12, comprising an external connection face (200) on which surface electronic components are mounted.

Images