Electronic module, associated mold and associated method for manufacturing

Abstract

The invention relates to an electronic module (1) comprising a lead frame (11) having at least one opening (115), a sleeve (12) conductively fastened to the lead frame (11), said sleeve (12) comprising a first end having a foot (121) having a cross-section complementary to the shape of the opening (115) in the lead frame (11), said foot (121) being housed in the opening (115) of the lead frame (11). The invention also relates to an associated mould and to a method for producing an electronic module (1).

Description

Technical Field

[0001] The present invention relates to the field of power electronics. More particularly, the present invention relates to an electronic module.

[0002] The present invention can be applied to, for example, an electronic system for a traction inverter, an on-vehicle charger for an electric pump for, for example, battery cooling, a heat pump, a laser sensor for, for example, autonomous driving, etc. Background Art

[0003] It is known to use sleeves to hold certain electrical pins of an electronic module. The electrical pins are forced into the sleeves so that the pins can be forced to remain above the electronic module.

[0004] As an example, Figure 1 An exemplary embodiment of a sleeve 12 is shown. In this example, the sleeve 12 is formed by a tube made of a conductive material such as copper, with each end bent downward into a collar. Each end of the sleeve 12 is open. These sleeves are used for welding, for example, to a lead frame.

[0005] Problems have arisen during the welding of the sleeves. Specifically, during this operation, as Figure 2 shown, the sleeves are prone to movement, resulting in a change in their position, and thus a change in the position of the electrical pins.

[0006] The object of the present invention is in particular to correct all or some of the drawbacks of the prior art by proposing a solution to reduce the positional dispersion of the sleeves during their welding. Summary of the Invention

[0007] To this end, the subject of the present invention is an electronic module, comprising:

[0008] A lead frame having at least one opening,

[0009] A sleeve conductively fastened to the lead frame, the sleeve comprising a first end having a foot, the foot having a cross-section complementary to the shape of the opening in the lead frame, the foot being received in the opening of the lead frame.

[0010] According to one embodiment, the sleeve is fastened by at least one of conductive bonding, welding or brazing.

[0011] According to one embodiment, the sleeve comprises a second end that can be deformed by compression.

[0012] According to one embodiment, the sleeve is fastened to the lead frame at the foot of the sleeve.

[0013] According to one embodiment, the sleeve comprises a fastening zone, such as a collar or a plurality of protrusions, and the sleeve is fastened to the lead frame by the fastening zone.

[0014] According to one embodiment, the sleeve includes a second end, and the second end of the sleeve has a flared shape.

[0015] According to one embodiment, the second end of the sleeve has a hemispherical shape.

[0016] Another subject of the present invention is a mold configured to cooperate with at least one sleeve of an electronic module as described above, the mold including at least one protrusion, the shape of which is complementary to the shape of the second end of the sleeve.

[0017] According to one embodiment, at least one protrusion has a hemispherical shape, and the diameter of the hemisphere of the protrusion is greater than the diameter of the hemisphere of the sleeve. In a variant, the diameter of the hemisphere of the protrusion is less than the diameter of the hemisphere of the sleeve.

[0018] According to one embodiment, the mold includes at least one through nozzle that opens at at least one protrusion.

[0019] A third subject of the present invention is a method for manufacturing an electronic module, including the following steps:

[0020] - Providing at least one lead frame;

[0021] - Forming an opening in the lead frame;

[0022] - Providing at least one sleeve having a first end including a foot, the foot having a cross-section complementary to the shape of the opening in the lead frame;

[0023] - Receiving the foot of the sleeve in the opening of the lead frame;

[0024] - Fastening the sleeve to the lead frame by a conductive device.

[0025] According to one implementation of the method, at least one sleeve includes a second end that can be deformed by compression, and the method further includes the following steps:

[0026] - Providing at least one mold including at least one protrusion whose shape is complementary to the shape of the second end of the sleeve;

[0027] - Applying the mold in contact with the sleeve;

[0028] - Deforming the second end of the sleeve by compression by means of at least one protrusion of the mold.

[0029] According to one implementation, the method further includes the following steps:

[0030] - Depositing a film, such as a fluoropolymer film, between the second end of the sleeve and at least one protrusion of the mold.

[0031] According to one implementation of the method, the fastening step is performed at the foot of the sleeve.

[0032] According to an embodiment of the method, the fastening step is performed in the fastening area of the sleeve.

[0033] According to an embodiment of the method, the fastening step is performed by one of brazing, welding or conductive bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] By reading the following description and referring to the drawings, other distinguishing features and advantages of the present invention will become more apparent. The following description is given in a non-limiting illustrative manner, in which:

[0035] Figure 1 Shows an exemplary embodiment of a sleeve known in the prior art, as described above;

[0036] Figure 2 Shows the dispersion of the sleeve during its fastening, as described above;

[0037] Figure 3 Is a schematic view of details centered on the sleeve before overmolding of an embodiment of an electronic module;

[0038] Figure 4 Shows details of the electronic module according to the present invention after overmolding;

[0039] Figure 5 Is a detail centered on a specific embodiment of the sleeve before overmolding of a variant of the embodiment of the electronic module;

[0040] Figure 6 Shows the fit between the sleeve end and the mold protrusion depending on the height of the sleeve;

[0041] Figure 7 Shows problems related to the height dispersion of the sleeve.

[0042] In the different drawings, similar elements are denoted by the same reference numerals. In addition, for the sake of presenting views that are easier to understand the present invention, the various elements are not necessarily shown to scale. DETAILED DESCRIPTION

[0043] Hereinafter, "the height of the sleeve" will denote the longitudinal distance of the sleeve. The same applies to "the height of the sleeve foot", which denotes the longitudinal distance of the sleeve foot.

[0044] For its part, "the height of the lead frame" refers to the distance along an axis perpendicular to the surface of the lead frame.

[0045] Figure 3 Shows details centered on the sleeve 12 before overmolding of an embodiment of an electronic module 1 according to the present invention.

[0046] According to one embodiment, the electronic module 1 includes a power module or an excitation module.

[0047] The electronic module 1 includes at least one lead frame 11 and at least one sleeve 12 fastened conductively to the lead frame 11.

[0048] The lead frame 11 can extend, for example, on an insulator 30.

[0049] The sleeve 12 can be fastened to the lead frame by bonding with the aid of a conductive adhesive. According to another embodiment, the sleeve 12 is soldered or brazed to the lead frame 11.

[0050] According to one embodiment, the sleeve 12 includes a foot 121 closing a first end of the sleeve 12.

[0051] According to one embodiment, the lead frame 11 includes at least one opening 115 at the location of the sleeve 12. This opening 115 is intended to receive the foot 121 of the sleeve 12. The foot 121 of the sleeve 12 has a cross section complementary in shape to the opening 115 in the lead frame 11.

[0052] The opening 115 of the lead frame 11 is, for example, a cylindrical blind hole or through hole. In this exemplary embodiment, the cross section of the foot 121 of the sleeve 12 is circular.

[0053] Preferably, the foot 121 extends over the entire height of the lead frame, thus ensuring good retention of the sleeve 12 in the lead frame 11.

[0054] In this way, by receiving the foot 121 of the sleeve 12 in the opening 115, the sleeve is directly anchored and referenced on the lead frame 11. Furthermore, the fact that the foot 121 of the sleeve is received in the lead frame 11 makes it possible to hold the sleeve 12 during the fastening of the sleeve 12. This thus reduces the risk of movement of the sleeve during this operation.

[0055] According to one embodiment, the sleeve 12 is fastened to the lead frame at its foot 121.

[0056] According to a variant of the embodiment, the sleeve 12 can include a fastening zone 125. This fastening zone 125 is intended to fasten the sleeve to the lead frame.

[0057] In Figure 3 the example, the fastening zone 125 is a collar extending around the entire circumference of the sleeve 12. This collar is fastened between the collar circumference and the lead frame 11 with the aid of a fastening joint 35, for example a brazing joint.

[0058] According to another embodiment, the fastening zone 125 may take the form of at least one fastening protrusion located around the periphery of the sleeve 12. The fastening zone 125 may be formed by two diametrically opposed fastening protrusions.

[0059] The sleeve 12 is intended to receive electrical connection pins (not shown). The electrical connection pins are forced through one end opposite the first end of the sleeve 12 having the foot 121. After insertion of the sleeve 12, the electrical connection pins are in electrical contact with the sleeve 12, which itself is in electrical contact with the lead frame 11.

[0060] Advantageously, the presence of the foot 121 closing the end of the sleeve 12 intended to be fastened to the lead frame 11 makes it possible to avoid solder entering the sleeve. Specifically, during the step of soldering the sleeve 12, the solder joint is deposited around the outer circumference of the collar. Thus, there is a risk of solder infiltrating the end of the sleeve and thus blocking the sleeve, preventing the insertion of the electrical connection pins.

[0061] Referring Figure 4 , after assembling the components of the electronic module 1, the mold 2 is applied to the assembly. Then, the epoxy resin 40 is injected to overmold the electronic module 1. The mold 2 is configured to cooperate with at least one sleeve 12 of the electronic module 1, and more specifically, with the second end 122 of said at least one sleeve 12.

[0062] Figure 5 Details centered on the sleeve 12 before overmolding of a variant embodiment of the electronic module 1 according to the invention are shown. In this example, the sleeve 12 is fastened to a transfer molded lead frame 11 (TML).

[0063] In this embodiment, the sleeve 12 is fastened between two conductive plates and is at the same electrical potential as the lead frame 11. For example, these may be two copper plates. These two conductive plates are in contact with the heat sink 50 through a layer of thermal grease or thermal adhesive 51.

[0064] The sleeve 12 is fastened to the lead frame 11, for example, by a fastening joint 35, such as a conductive bonding joint between two diametrically opposed fastening protrusions and the lead frame 11.

[0065] In this embodiment, the height of the foot of the sleeve 12 is less than the height of the lead frame 11.

[0066] Figure 5 A specific embodiment of the sleeve 12 according to the invention is also shown. In this example, the inner part of the second end 122 of the sleeve 12, that is to say the end opposite the first end having the foot 121, has a flared shape.

[0067] According to a specific embodiment, the inner part of the second end 122 of the sleeve 12 is hemispherical.

[0068] According to an embodiment variant, the second end 122 of the sleeve 12 can be deformed by compression.

[0069] Referring Figure 6 to, the present invention also relates to a mold 2 configured to cooperate with at least one sleeve 12 of the electronic module 1, and more specifically, to cooperate with the interior of its second end 122.

[0070] In the embodiment shown in this figure, the mold 2 includes at least one protrusion 21. The protrusion 21 has a shape complementary to the shape of the inner part of the second end of at least one sleeve 12, and the protrusion 21 will cooperate with this inner part.

[0071] According to one embodiment, the mold 2 has at least one protrusion 21 that is hemispherical. Similarly, the inner part of the second end 122 of the sleeve 12 with which the protrusion 21 will cooperate has a hemispherical flared shape. According to the distinguishing feature of the present invention, the diameter of the hemisphere of the protrusion 21 is greater than the diameter of the hemisphere of the inner part of the second end 122 of the sleeve 12 with which the protrusion 21 will cooperate.

[0072] According to one embodiment, the mold includes at least one through nozzle 22 that opens at at least one protrusion 21 of the mold 2.

[0073] Advantageously, the flared shape and deformable characteristics of the second end 122 of the sleeve 12 cooperate with the protrusion 21 having a complementary shape of the mold 2, so that the height dispersion of the sleeve 12 can be compensated. Referring Figure 6 to 7 and

[0074] In Figure 7 the example of, the height of the sleeve 12c is less than the height of the other sleeve 12d. When the mold 2 is applied in contact with the second end 122d of the sleeve 12d, the second end 122c of the sleeve 12c does not contact the mold 2. Therefore, there is a free space between the open second end 122c and the mold 2. Therefore, during the overmolding step, for example, by injecting epoxy resin, the resin easily penetrates into the sleeve 12c, thereby blocking the sleeve 12c. Thereafter, it will be impossible to introduce electrical connection pins.

[0075] Figure 6Shows the fit between the inner part of the second ends 122b, 122c, 122d of the sleeves 12b, 12c, 12d and the protrusions of the mold 2 depending on the height of the sleeves. In this example, the inner parts of the second ends 122a, 122b, 122c, 122d of the sleeves 12a, 12b, 12c, 12d have a hemispherical shape and can be deformed by compression. The protrusion 21 of the mold 2 also has a hemispherical shape.

[0076] The second end 122a of the sleeve 12a does not contact the mold 2. This sleeve allows the shape of the second end 122a before compression to be seen.

[0077] It is considered that the sleeve 12d has the correct height. Its second end 122d fits perfectly with the protrusion 21 of the mold 2. Thus, the mold 2 correctly blocks the second end 122d of the sleeve 12d, thereby preventing any resin from infiltrating into the sleeve 12d during the resin injection step.

[0078] The height of the sleeve 12c is less than the normal value. When the protrusion 21 of the mold 2 contacts the second end 122c of this sleeve 12c, the two elements do not fit well. However, the protrusion 21 of the mold 2 slightly compresses the second end 122c of the sleeve 12c, thereby ensuring the closure of the second end 122c. Thus, this prevents any resin from entering the sleeve 12c during the overmolding step.

[0079] The height of the sleeve 12b is greater than the normal value. When the protrusion 21 of the mold 2 contacts the second end 122b of this sleeve 12b, the two elements fit to a great extent. The protrusion 21 of the mold 2 completely compresses the second end 122b of the sleeve 12b. The flexibility of the second end 122b allows the mold 2 not to be blocked and allows the mold 2 to be correctly positioned relative to the other sleeves. This flexibility also allows the protrusion 21 of the mold 2 to close the second end 122b. Thus, even if the height of the sleeve is greater than the normal height, resin can be prevented from entering the sleeve 12b.

[0080] The present invention also relates to a method for manufacturing the electronic module 1 as described above. The method includes the following steps:

[0081] - Providing at least one lead frame 11;

[0082] - Forming an opening 115 in the lead frame 11;

[0083] - Providing at least one sleeve 12 having a first end including a foot 121, the foot having a cross-section complementary to the cross-section of the opening 115 in the lead frame 11;

[0084] - Receiving the foot 121 of the sleeve 12 in the opening 115 of the lead frame 11;

[0085] - Fasten the sleeve 12 to the lead frame 11 through a conductive device.

[0086] According to an embodiment of the method, the opening 115 can be a round hole. In this particular case, the cross-section of the foot 121 of the sleeve 12 is also round.

[0087] The opening 115 can be produced by subjecting the lead frame 11 to a process of chemical etching.

[0088] According to an embodiment, the step of fastening the foot 121 in the lead frame 11 can be carried out by conductive bonding, by soldering or by brazing.

[0089] According to an embodiment, the step of fastening the foot 121 in the lead frame 11 is carried out at the foot 121 of the sleeve 12.

[0090] According to an implementation variant, the step of fastening the foot 121 in the lead frame 11 is carried out at the fastening region 125 of the sleeve 12.

[0091] According to an embodiment of the method, during the step of providing at least one sleeve 12, the at least one sleeve 12 includes a second end 122 that can be deformed by compression. The method further includes the following steps:

[0092] - Provide at least one mold 2, which includes at least one protrusion 21, the shape of which is complementary to the shape of the second end 122 of the at least one sleeve 12;

[0093] - Apply the mold 2 in contact with the second end 122 of the at least one sleeve 12;

[0094] - By means of at least one protrusion 21 of the mold 2, deform the second end 122 of the at least one sleeve 12 by compression.

[0095] According to an embodiment, the method further includes the step of depositing a film between the second end 122 of the at least one sleeve 12 and the at least one protrusion 21 of the mold 2.

[0096] According to an embodiment, the film is a fluoropolymer film.

[0097] According to an embodiment, the method includes an overmolding step, during which, after applying the mold 2 in contact with the second end 122 of the at least one sleeve 12, a resin such as epoxy resin is injected onto the various elements of the electronic module 1.

[0098] According to an embodiment, the method includes a step of polymerizing the overmolding resin.

[0099] The present invention has been described above using the embodiments presented in the drawings without limiting the general inventive concept.

[0100] After considering the different embodiments shown in this application, those skilled in the art will come up with many other modifications and variations.

[0101] These embodiments are given by way of example and are not intended to limit the scope of the invention, which is determined only by the following claims.

[0102] In the claims, the word "comprising" does not exclude other elements or steps.

[0103] The fact that various features are recited in mutually dependent claims does not mean that combinations of these features can be used advantageously. Finally, any reference used in the claims should not be construed as limiting the scope of the invention.

Claims

1. An electronic module (1), comprising: A lead frame (11) having at least one opening (115), A sleeve (12) is conductively fastened to a lead frame (11), the sleeve (12) comprising a first end having a foot (121) having a cross-section complementary in shape to an opening (115) in the lead frame (11), the foot (121) being received in the opening (115) of the lead frame (11).

2. Electronic module (1) according to the preceding claim, wherein The sleeve (12) includes a second end (122) which is deformable by compression.

3. The electronic module (1) according to any one of claims 1 and 2, wherein: The sleeve (12) is fastened to the lead frame (11) at a foot (121) of the sleeve (12).

4. The electronic module (1) according to any one of the preceding claims, wherein: The sleeve (12) comprises a fastening area (125), such as a collar or a plurality of protrusions, by which the sleeve (12) is fastened to the lead frame (11).

5. The electronic module (1) according to any one of the preceding claims, wherein: The sleeve (12) comprises a second end (122), the second end (122) of the sleeve (12) having a flared shape.

6. A mold (2) configured to cooperate with at least one sleeve (12) of an electronic module (1) according to any one of the preceding claims, wherein the mold (2) is characterized in that it includes at least one protrusion (21) whose shape is complementary to the shape of the second end (122) of the sleeve (12).

7. The mould (2) according to the preceding claim, comprising at least one through-nozzle (22) opening at the at least one protuberance (21).

8. A method for manufacturing an electronic module (1), comprising the following steps: - providing at least one lead frame (11); - forming an opening (115) in the lead frame (11); - providing at least one sleeve (12) having a first end including a foot (121) having a cross-section complementary in shape to the opening (115) in the lead frame (11); - receiving the foot (121) of the sleeve (12) in the opening (115) of the lead frame (11); - Fastening the sleeve (12) to the lead frame (11) by means of conductive means.

9. The method according to the preceding claim, wherein: The at least one sleeve (12) comprises a second end (122) which is deformable by compression, and the method further comprises the following steps: - providing at least one mould (2) comprising at least one protrusion (21) having a shape complementary to the shape of the second end (122) of the sleeve (12); - applying the mould (2) in contact with the sleeve (12); - Deforming the second end (122) of the sleeve (12) by compression with the aid of at least one protrusion (21) of the mould (2).

10. The method according to the preceding claim, further comprising the steps of: A film, such as a fluoropolymer film, is deposited between the second end (122) of the sleeve (12) and at least one protrusion (21) of the mold (2).

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