Power module with overmoulding

Abstract

The invention relates to a power module (300) comprising: - electrical conductors (302), each of which has an upper face (304); - at least one semiconductor component (306) attached to the upper face (304) of one of the conductors (302); and - an overmoulding (310) that extends over at least one portion of the upper face (304) of each of the conductors (304). At least one of the upper faces (304) has, in its overmoulded portion, at least one attachment groove (404) which is filled by the overmoulding (310) and passes through a point (P) on the upper face (304) that experiences a mechanical stress (T) as a result of the overmoulding (310), the attachment groove (404) forming, at this point (P), at a predefined temperature, an angle with the mechanical stress (T) of between 60° and 120°, preferably between 85° and 95°, and more preferably 90°.

Description

Description TITLE: POWER MODULE WITH OVERMOLDING Technical field of the invention

[0001] The present invention relates to a power module with overmolding, a voltage converter comprising such a power module, an electric drive device comprising such a voltage converter, a mobility device comprising such a power module or such an electric drive device, as well as a method for manufacturing a power module.

[0002] A mobility device is, for example, a motorized land vehicle, a train, an aircraft, or a drone. A motorized land vehicle is, for example, a motor vehicle, a motorcycle, a motorized bicycle, or a motorized wheelchair. Technological background

[0003] Known from the state of the art is a power module comprising: electrical conductors each having an upper face; at least one semiconductor component fixed on the upper face of one of the conductors; and an overmolding extending over at least part of the upper face of each of the conductors.

[0004] When manufacturing such a power module, and in particular during overmolding, epoxy resin is usually injected at high temperature onto the previously heated copper conductors.

[0005] During cooling of the assembly, upward bending was observed, resulting in mechanical shear stresses between the conductors and the overmolding.

[0006] However, the mechanical adhesion between the conductors and the overmolding is weak to allow wiring and the chemical adhesion is also weak, coming only from Van der Waals chemical bonds, which are easily weakened by impurities (for example, one or more of: chlorine, tin, silicone (PDMS)) having slipped between the conductors and the overmolding.

[0007] These mechanical constraints therefore lead to a significant risk of delamination of the overmolding, and therefore a loss of reliability of the power module.

[0008] It may therefore be desirable to provide a power module which makes it possible to overcome at least some of the aforementioned problems and constraints. Summary of the invention

[0009] A power module is therefore proposed comprising: electrical conductors each having an upper face; at least one semiconductor component fixed on the upper face of one of the conductors; and an overmolding extending over at least a part of the upper face of each of the conductors; characterized in that at least one of the upper faces has, in its overmolded part, at least one attachment groove filled by the overmolding and passing through a point on the upper face undergoing mechanical stress from the overmolding, the attachment groove making at this point, at a predefined temperature, an angle with the mechanical stress of between 60° and 120°, preferably between 85° and 95°, more preferably 90°.

[0010] Thus, thanks to the invention, the gripping grooves provide good adhesion between the conductors and the overmolding, reducing the risk of delamination.

[0011] The invention may further comprise one or more of the following optional features, in any technically possible combination.

[0012] Optionally, the mechanical stress results at least in part from a difference in coefficient of thermal expansion between the conductor carrying the attachment groove and the overmolding.

[0013] Also optionally, the preset temperature is between -50°C and 200°C, for example the preset temperature is room temperature, for example 25°C.

[0014] Optionally also, the predefined temperature is the temperature resulting at the point of the upper face undergoing the mechanical stress of a temperature gradient between one or more hot spots of the power module and the rest of the structure of the power module, for example the hot spot can be the semiconductor component fixed on the upper face of one of the conductors of the power module at its operating temperature, said temperature of operating temperature being for example 175°C. Thus, the hot spot is located at the location of the semiconductor component.

[0015] For example, said hot spots may be the semiconductor components of the power module at their operating temperature, said operating temperature being, for example, 175°C. Thus, the hot spots are located at the location of the semiconductor components.

[0016] The operating temperature is by definition the usual operating temperature of the semiconductor component(s) of the power module, this usual temperature being that of normal operation of the semiconductor component(s), as defined for example by the technical data sheet of the semiconductor component(s) or by the technical data sheet of the power module or by operating tests of the power module.

[0017] Optionally also, the hooking groove is located at least 0.3 mm from the semiconductor component(s).

[0018] Also optionally, the hanging groove is straight.

[0019] Also optionally, the upper faces of the conductors are flat and coplanar.

[0020] Optionally, the conductors also have thicknesses perpendicular to their upper faces of more than 1 mm.

[0021] Also optionally, the overmolding is in epoxy resin.

[0022] Optionally, the conductors are also made of copper.

[0023] Also optionally, the hanging groove has a length and a width perpendicular to its length, of at most 5% of its length.

[0024] Also optionally, the hooking groove has a bottom and two side walls extending from the bottom to the upper face of the conductor carrying the hooking groove, the two side walls being perpendicular to the upper face.

[0025] Also optionally, the hooking groove has a bottom and two side walls extending from the bottom to the upper face of the conductor carrying the hooking groove, one of the side walls being perpendicular to the upper face and the other being oblique to the upper face.

[0026] Also optionally, the hooking groove has a bottom and two side walls extending from the bottom to the upper face of the conductor carrying the hooking groove, the two side walls being oblique relative to the upper face.

[0027] Optionally, the oblique side wall or side walls form an angle of between 30° and 60° with the upper face.

[0028] Also optionally, the hanging groove has a depth and width at the upper face of between 90% and 110% of the depth.

[0029] Also optionally, the power module has two parallel hooking grooves on the upper face of the same electrical conductor without any other hooking groove between them.

[0030] Also optionally, the power module comprises two parallel hooking grooves on the upper face of the same electrical conductor without another hooking groove between them, the intersection between the projection of one of the two grooves in the direction orthogonal to its length along the upper surface of the conductor on the straight line defined by the other of the two grooves and the other of the two grooves is non-empty.

[0031] Also optionally, each of the two parallel hooking grooves has a depth and a width at the upper face, these two parallel hooking grooves being separated from each other by a distance greater than five times the depth and / or the width of each of the two.

[0032] Also optionally, the power module has two hooking grooves on the upper face of the same electrical conductor, perpendicular to each other.

[0033] Also optionally, the power module comprises two attachment grooves on the upper face of the same electrical conductor, said attachment grooves each passing through a point located along the same iso-stress line.

[0034] Thus, iso-stressed lines represent lines where the mechanical stresses are of the same intensity.

[0035] Preferably, the iso-stress lines represent lines where mechanical stresses of the same intensity are exerted perpendicular to said iso-stress lines.

[0036] Also optionally, the power module comprises two attachment grooves on the upper face of the same electrical conductor, said attachment grooves each passing through a point undergoing a mechanical stress of the same intensity.

[0037] Also optionally, the power module includes several semiconductor components implementing a switching arm.

[0038] Also proposed is a voltage converter comprising at least one power module according to the invention, and a system for controlling the semiconductor component(s) of the power module(s).

[0039] Also provided is an electric drive device comprising a voltage converter according to the invention, designed to perform AC-DC power conversion, and an electric machine connected to the voltage converter.

[0040] A mobility device is also proposed comprising a power module according to the invention, or a voltage converter according to the invention, or an electric drive device according to the invention.

[0041] There is also provided a method for manufacturing a power module with electrical conductors each having an upper face, at least one semiconductor component fixed on the upper face of one of the conductors and an overmolding extending over at least a portion of the upper face of each of the conductors, the method comprising: an evaluation, in the power module to be manufactured, of a mechanical stress exerted by the overmolding at a point on the upper face of one of the conductors; a production of at least one attachment groove on the upper face, the attachment groove passing through the point where the mechanical stress was evaluated and at this point making an angle with the mechanical stress of between 60° and 120°, preferably between 85° and 95°; a fixing of the one or more semiconductor components (306) on the upper face of one of the conductors; and overmolding of the conductors and in particular of at least part of the upper face where the attachment groove has been made, so as to fill the attachment groove with the overmolding.

[0042] Optionally, the hooking groove is located at least 0.3 mm from the semiconductor component(s).

[0043] Optionally, the hanging groove is made by stamping. Brief description of the figures

[0044] The invention will be better understood with the aid of the following description, given solely by way of example and with reference to the appended drawings in which: Figure 1 is a schematic view of a land motor vehicle in which the invention can be implemented, Figure 2 is an electrical diagram of a voltage converter of the vehicle of Figure 1, Figure 3 is a simplified side sectional view of a power module of the voltage converter of Figure 2, Figure 4 is a top view of the power module, with transparent overmolding and in the absence of wiring of semiconductor components of the power module, Figure 5 is a top view of a hooking groove provided on an upper face of an electrical conductor of the power module, Figure 6 is a simplified side sectional view of the hooking groove, illustrating a first possible profile,Figure 7 is a simplified side sectional view of the hooking groove, illustrating a second possible profile, Figure 8 is a simplified side sectional view of the hooking groove, illustrating a third possible profile, Figure 9 is a simplified side sectional view of two successive parallel grooves, Figure 10 is a block diagram illustrating the steps of a manufacturing method of the power module, Figure 11 is a top view of a stamped plate, during the process of Figure 10, Figure 12 is a top view of the plate after cutting, as provided in the process of Figure 10, Figure 13 is a view similar to that of Figure 4, with a different layout of the hooking grooves, Figure 14 is a side view illustrating a camber due to a shrinkage of the overmolding, and Figure 15 is a side view illustrating a camber due to a difference in thermal coefficient of expansion. Detailed description of the invention

[0045] With reference to Figure 1, a motor land vehicle 100 in which the invention can be implemented will now be described.

[0046] The vehicle 100 comprises one or more drive wheels 102 configured to put the vehicle 100 into motion.

[0047] To drive the drive wheel(s) 102, the mobility device 100 further comprises an electric drive device 104 and a direct voltage source 106, such as a battery, configured to electrically power the electric drive device 104.

[0048] The electric drive device 104 comprises an electric machine 108, in particular polyphase, for example three-phase, connected to the drive wheels 102 to drive the latter. The electric drive device 104 further comprises an AC-DC electric voltage converter 110 connected between the DC voltage source 106 and the electric machine 108. The electric voltage converter 110 is configured to transfer electric power between the DC voltage source 106 and the electric machine 108. For example, the AC-DC converter 110 is configured to operate as an inverter to transfer electric power from the DC voltage source 106 to the electric machine 108 operating as an electric motor. The AC-DC converter 110 may also be configured to operate as a rectifier to transfer electric power from the electric machine 108 operating as an electric generator up to the direct voltage source 106, for example to recharge the latter.

[0049] Referring to Figure 2, the electrical voltage converter 110 includes a switching circuit 202 with low side switches Q and high side switches Q'.The switches Q, Q' are semiconductor switches, for example transistors, such as metal-oxide gate field effect transistors (also known as MOSFET) or silicon metal-oxide gate field effect transistors (also known as Si MOSFET) or silicon carbide metal-oxide gate field effect transistors (also known as SiC MOSFET) or insulated gate bipolar transistors (also known as IGBT) or gallium nitride field effect transistors (also known as the acronym GaN FET).

[0050] The switching circuit 202 comprises, for example, at least one switching arm 206, for example, as many switching arms 206 as there are stator phases of the electrical machine 108. Each switching arm 206 comprises a high-side switch Q' and a low-side switch Q connected to each other at a midpoint. Each switching arm is connected between terminals +, - of the DC voltage source 106. The midpoint is connected to one of the stator phases of the electrical machine 108.

[0051] Each switching arm 206 is thus configured to switch between two configurations. In a first configuration, the high-side switch is closed and the low-side switch is open, such that a DC voltage is essentially applied to the midpoint and thus to the stator phase connected thereto. In a second configuration, the high-side switch is open and the low-side switch is closed, such that a zero voltage is applied to the midpoint and thus to the associated stator phase.

[0052] The electrical voltage converter 110 further comprises a device 208 for controlling the switches Q, Q' generally through respective drivers (not shown). The control device 208 is for example designed to control the switches Q, Q' in order to regulate phase currents transmitted to the stator phases from the midpoints.

[0053] At least one of the switching arms 206 is for example implemented in a power module.

[0054] With reference to Figure 3, the power module, designated by the reference 300, firstly comprises several electrical conductors 302, for example made of copper. These conductors 302 are rigid and have an upper face 304. For example, the upper faces 304 are flat and coplanar. The conductors 302 for example all have the same thickness, perpendicular to their upper faces 304. This thickness is preferably more than 1 mm, in order to allow sufficient current to pass for power applications. For example, as will be described later, the conductors 302 are obtained by cutting out the same initial plate.

[0055] The power module 300 further comprises at least one semiconductor component 306 forming for example at least in part one of the switches Q, Q' of FIG. 2. Each semiconductor component 306 is fixed on the upper face 304 of a respective one of the conductors 302. Certain conductors 302 may be devoid of a semiconductor component.

[0056] The power module 300 further comprises wiring 308, for example ribbons or wires, for connecting each semiconductor component to a conductor 302 other than that carrying the semiconductor component.

[0057] The power module 300 further comprises an overmolding 310 extending over at least a portion of the upper face 304 of each of the conductors 302, in order to coat, in the example described here, each semiconductor component 306 and its wiring 308. The overmolding 310 is for example made of epoxy resin.

[0058] For example, epoxy resin has: a coefficient of thermal expansion (CTE) less than or equal to 11 ppm / °C and / or a Young's modulus greater than or equal to 18 GPa and / or a volume shrinkage less than or equal to 0.2%.

[0059] The copper of the 302 conductors has, for example: a CTE greater than or equal to 17 ppm / °C and / or a Young's modulus greater than or equal to 120 GPa and / or a coefficient of friction with the epoxy resin greater than or equal to 0.3.

[0060] With reference to Figure 4, the upper faces 304 of the conductors 302 carrying a semiconductor component 306 have, around each semiconductor component 306, confinement grooves 402. These confinement grooves 402 are attached to the semiconductor components 306 (less than 0.1 mm from the latter) and have the function of ensuring the position of the semiconductor component 306 on the conductor 302 and of preventing overflow of the alloy used for soldering. This function is obtained by the fact that the confinement grooves 402 generate a geometric break with the upper face 304 of the conductor 302 which catches the meniscus of the molten alloy during soldering. For the sake of clarity, the confinement grooves 402 are referenced only for one of the semiconductor components 306.

[0061] Furthermore, at least one of the upper faces 304 of the conductors 302 has, in its overmolded portion, at least one hooking groove 404 filled by the overmolding 310, the limits of which are illustrated by dotted lines in FIG. 4. For example, as in the illustrated example, all the upper faces 304 of the conductors 302 have several hooking grooves 404. For the sake of clarity, only some are referenced in FIG. 4.

[0062] The hooking grooves 404 are distributed on the upper faces, and are located at least 0.3 mm from each semiconductor component 306.

[0063] For example, each hooking groove 404 is straight, i.e., extends across the upper face 304 in a straight line. Compared to other shapes, this simplifies their production.

[0064] Furthermore, several hooking grooves 404 are preferably parallel to each other, one behind the other in a direction perpendicular to each of them, without any other hooking groove between them, like those circled by dotted lines in FIG. 4. In particular, if two successive grooves are considered in this perpendicular direction, the intersection between the projection of one of these two successive grooves in the direction orthogonal to its length along the upper surface of the conductor on the straight line defined by the other of these two successive grooves and the other of these two successive grooves is non-empty.

[0065] With reference to Figure 5, each attachment groove 404 passes through a point P of the upper face 304 undergoing a mechanical stress T from the overmolding 310. The attachment groove 404 is thus made to make at this point P an angle A1 with the mechanical stress T of between 60° and 120°, preferably between 85° and 95°, more preferably 90°. The mechanical stress T considered is that existing at a predefined temperature of the conductor 302 and the overmolding 310 around the attachment groove 404. This predefined temperature is for example between -50°C and 200°C, i.e. the usual range of temperatures encountered by the power module, when stopped and in operation. The predefined temperature may be different from one attachment groove 404 to another.For example, the orientation of some or all of the latching grooves 404 may be defined with a predefined uniform temperature field, for example 25°C (room temperature), or by considering a predefined temperature field with gradient between one or more hot spots and the rest of the structure. For example, the hot spots may be the semiconductor components considered at a predefined temperature, for example 175°C (their usual operating temperature).

[0066] The mechanical stress T results at least in part from a difference in CTE between the conductor 302 carrying the attachment groove 404 and the overmolding 310.

[0067] Furthermore, each hooking groove 404 has a length Lo and a width La perpendicular to its length Lo and taken at the level of the upper face 304, that is to say in the continuity of the latter. The width La is preferably at most 5% of its length Lo, more preferably at most 3%.

[0068] The hooking groove 404 is preferably placed so that the point P through which it passes is located substantially in its middle, for example between 40% and 60% of the length Lo

[0069] With reference to FIG. 6, each hooking groove 404 has a bottom 602, that is to say the part of the hooking groove 404 furthest from the upper face 304. Each hooking groove 404 also has two side walls 604A, 604B extending from the bottom 602 to the upper face 304.

[0070] Furthermore, each hooking groove 404 has a depth Pr (distance between the bottom 602 and the upper face 304) substantially equal to its width La. For example, width La is between 90% and 110% of depth Pr.

[0071] For example, the two side walls 604A, 604B are perpendicular to the upper face 304.

[0072] According to a simple model of forces applying to the part of the overmolding 310 present in the hooking groove 404 (this part being identified by dotted lines), this part of the overmolding 310 undergoes two lateral forces FA, FB from the side walls 604A, 604B and a detachment force FU at the top of the hooking groove 404. Considering this simple model, detachment occurs when the detachment force FU becomes greater than the sum of the two friction forces against the two side walls 604A, 604B, i.e. when the detachment force FU becomes greater than: fx FA + fx FB = fx FC, with FC = FA + FB and f the coefficient of friction between the overmolding 310 and the side walls 604A, 604B assumed to be identical for the two walls 604A, 604B. Thus, the detachment threshold is fx FC.

[0073] With reference to Figure 7, alternatively, the two side walls 604A, 604B are oblique relative to the upper face 304. Preferably, each of the side walls 604A, 604B makes, with the upper face 304, an angle A2, respectively A3, between 30° and 60° with the upper face (FS). The two angles A2, A3 are for example equal. These angles A2, A3 are measured in the hooking groove 404, as illustrated.

[0074] Considering the same simple model as in Figure 6, the detachment threshold with the two oblique side walls 604A, 604B with the same angle A = A2 = A3 is fx cos 2 (A) x FC.

[0075] Referring to Figure 8, alternatively, one 604A of the side walls 604A, 604B is perpendicular to the upper face 304 and the other 604B is oblique to the upper face 304.

[0076] Preferably, the oblique side wall 604B makes, with the upper face 304, an angle A4 of between 30° and 60° with the upper face (FS). The angle A4 is taken in the hooking groove 404, as illustrated.

[0077] Considering the same simple model as in Figure 6, the detachment threshold with one side wall 604A perpendicular and the other 604B oblique, is 0.5 xfx (1 + cos 2 (A4) x FC.

[0078] Thus, the peel threshold may be higher for the embodiment of Figure 8, compared to the embodiments of Figures 6 and 7.

[0079] With reference to Figure 9, two parallel hooking grooves 404 are preferably separated from each other by a distance D greater than five times the depth Pr and / or the width La of each of the two.

[0080] With reference to Figure 10, an example of a method 1000 according to the invention, for manufacturing the power module 300 of the preceding figures, will now be described.

[0081] During a step 1002, an initial plate is obtained. The plate is for example made of copper and has for example a thickness greater than 1 mm.

[0082] During a step 1004, an evaluation is carried out, in the power module 300 to be manufactured, of a mechanical stress T exerted by the overmolding 310 at each of several points P of at least one of the upper faces 304 of the conductors 302. This evaluation is for example carried out by a numerical simulation or by measurements on a test power module, identical to that to be manufactured, in both cases in the absence of attachment grooves. Indeed, the presence of attachment grooves does not substantially change the stresses exerted by the overmolding 310 on the surfaces 314.

[0083] For example, iso-stress lines are determined and the mechanical stresses T at several points P of each of them are evaluated.

[0084] During a step 1006, the result of which is illustrated in FIG. 11, the confinement grooves 402 and the attachment grooves 404 are produced on the plate, designated by the reference 1102. In particular, the attachment grooves 404 are placed on the points P respectively, making at the associated point P an angle with the evaluated mechanical stress T of between 60° and 120°, preferably between 85° and 95°, more preferably 90°. Thus, several grooves can be provided along the same iso-stress line.

[0085] The containment grooves 402 and / or the attachment grooves 404 are for example made by stamping the initial plate. As the plate is not yet cut, it is easy to position the counter-supports allowing stamping.

[0086] Returning to Figure 10, during a step 1008, the result of which is illustrated in Figure 12, the plate is cut to obtain the conductors 302, with holding tabs 1202 (only some are referenced in figure 12 for clarity).

[0087] Returning to Figure 10, during a step 1010, the semiconductor components 306 are each fixed on an upper face 304 of one of the conductors 302, and the wiring 308 is carried out.

[0088] During a step 1012, the overmolding 310 is carried out in order, in the example described here, to cover the conductors 302 and their wiring 308, as well as the attachment grooves 404, so as to fill the latter.

[0089] For example, the cut plate, with the semiconductor components 306 and the wiring 308 are heated. The conductors 302 then expand according to their CTE.

[0090] Then, the assembly is introduced into a preheated mold, where epoxy resin at a temperature above 150°C, for example 175°C, is injected. The epoxy resin then begins to crosslink and contracts (volume shrinkage effect in English), causing a slight downward curvature, for example of a few hundredths of a millimeter. The result is illustrated in Figure 14.

[0091] The assembly is then removed from the mold and cooled to room temperature to complete the crosslinking. This cooling is accompanied by a contraction of the conductors 302 and the overmolding 310, to different amplitudes due to their difference in CTE. These new constraints cause an upward bending, much greater than the downward bending due to the crosslinking of the epoxy resin. The result is illustrated in Figure 15.

[0092] Thus, the risk of detachment is mainly due to this upward camber and therefore to the difference in CTE. This risk is nevertheless greatly reduced by the presence of the 404 attachment grooves.

[0093] During a step 1014, called separation, the holding tabs are cut.

[0094] With reference to Figure 13, in some embodiments, hooking grooves 404 may be provided perpendicular to others. This makes it possible to prevent the overmolding 310 from sliding along the hooking grooves 404.

[0095] In conclusion, it will be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications may be made to the embodiments described above, in light of the teaching which has just been disclosed to him.

[0096] In the detailed presentation of the invention given above, the terms used should not be interpreted as limiting the invention to the embodiments set forth in this description, but should be interpreted to include all equivalents the prediction of which is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching just disclosed to them.

Claims

Claims [1] Power module (300) comprising: electrical conductors (302) each having an upper face (304); at least one semiconductor component (306) fixed on the upper face (304) of one of the conductors (302); and an overmolding (310) extending over at least a portion of the upper face (304) of each of the conductors (304); characterized in that at least one of the upper faces (304) has, in its overmolded part, at least one hooking groove (404) filled by the overmolding (310) and passing through a point (P) of the upper face (304) undergoing a mechanical stress (T) from the overmolding (310), the hooking groove (404) making at this point (P), at a predefined temperature, an angle with the mechanical stress (T) of between 60° and 120°, preferably between 85° and 95°, more preferably 90°. [2] Power module (300) according to claim 1, in which the mechanical stress (T) results at least in part from a difference in coefficient of thermal expansion between the conductor (302) carrying the attachment groove (404) and the overmolding (310). [3] Power module (300) according to claim 1 or 2, wherein the hooking groove (404) is located at least 0.3 mm from the one or more semiconductor components (306). [4] Power module (300) according to any one of claims 1 to 3, in which the hooking groove (404) is straight. [5] Power module (300) according to any one of claims 1 to 4, in which the hooking groove (404) has a length (Lo) and a width (La) perpendicular to its length (Lo), of at most 5% of its length (Lo). [6] Power module (300) according to any one of claims 1 to 5, in which the hooking groove (404) has a bottom (602) and two side walls (604A, 604B) extending from the bottom (602) to the upper face (304) of the conductor (302) carrying the hooking groove (404), the two side walls (604A, 604B) being perpendicular to the upper face (304). [7] Power module (300) according to any one of claims 1 to 5, in which the hooking groove (404) has a bottom (602) and two side walls (604A, 604B) extending from the bottom (602) to the upper face (304) of the conductor (302) carrying the hooking groove (404), one (604A) of the side walls (604A, 604B) being perpendicular to the upper face (304) and the other (604B) being oblique relative to the upper face (304). [8] Power module (300) according to any one of claims 1 to 5, in which the hooking groove (404) has a bottom (602) and two side walls (604A, 604B) extending from the bottom (602) to the upper face (304) of the conductor (302) carrying the hooking groove (404), the two side walls (604A, 604B) being oblique relative to the upper face (304). [9] Power module (300) according to claim 7 or 8, in which the oblique side wall (604B) or the oblique side walls (604A, 604B) make, with the upper face, an angle (A4) of between 30° and 60° with the upper face (304). [10] Power module (300) according to any one of claims 1 to 9, comprising two parallel hooking grooves (404) on the upper face (304) of the same electrical conductor (302) without any other hooking groove between them. [11] Power module (300) according to claim 10, in which each of the two parallel hooking grooves (404) has a depth (P) and a width (L) at the upper face (304), these two parallel hooking grooves (404) being separated from each other by a distance greater than five times the depth (P) and / or the width (L) of each of the two. [12] Power module (300) according to any one of claims 1 to 11, comprising two attachment grooves (404) on the upper face (304) of the same electrical conductor (302), perpendicular to each other. [13] Voltage converter comprising at least one power module (300) according to any one of claims 1 to 12, and a system (208) of control of the semiconductor component(s) (306) of the power module(s) (300). [14] An electric drive device comprising a voltage converter according to claim 13, adapted to perform AC-DC power conversion, and an electric machine connected to the voltage converter. [15] Mobility device comprising a power module according to any one of claims 1 to 12, or a voltage converter according to claim 13, or an electric drive device according to claim 14. [16] Method for manufacturing a power module (300) with electrical conductors (302) each having an upper face (304), at least one semiconductor component (306) fixed on the upper face (304) of one of the conductors (302) and an overmolding (310) extending over at least a portion of the upper face (304) of each of the conductors (302), the method comprising: an evaluation, in the power module (300) to be manufactured, of a mechanical stress (T) exerted by the overmolding (310) at a point (P) of the upper face (304) of one of the conductors (302); an embodiment of at least one hooking groove (404) on the upper face (304), the hooking groove (404) passing through the point (P) where the mechanical stress (T) was evaluated and makes at this point (P) an angle (A1) with the mechanical stress (T) of between 60° and 120°, preferably between 85° and 95°;fixing the semiconductor component(s) (306) on the upper face (304) of one of the conductors (302); and overmolding the conductors (302) and in particular at least part of the upper face (304) where the attachment groove (404) has been made, so as to fill the attachment groove (404) with the overmolding (310).;

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