Housing part for a semiconductor module

Abstract

The invention relates to a housing part (2) for a semiconductor module (22). In order to facilitate a reliable wiring, the invention proposes that the housing part (2) comprises the following components: a housing frame (4) which has a support surface (8) and a guide groove (10) extending at an angle (φ) to the support surface (8); a pin (6) which is inserted into the guide groove (10) and has a foot (12) and a shaft (14) extending at an angle (φ) to the foot (12), said shaft (14) of the pin (6) being form-fittingly held in the guide groove (10) of the housing frame (4); and a damping layer (20), via which the foot (12) of the pin (6) is integrally bonded to the support surface (8) of the housing frame (4).

Description

[0001] Description

[0002] Housing part for a semiconductor module

[0003] The invention relates to a housing part for a semiconductor module.

[0004] Furthermore, the invention relates to a semiconductor module with at least one such housing part.

[0005] Furthermore, the invention relates to a power converter with at least one such semiconductor module.

[0006] Furthermore, the invention relates to a method for producing a semiconductor module.

[0007] Such a housing part can, among other things, be part of a housing for a power semiconductor module, which is generally used in a power converter. A power converter can be, for example, a rectifier, an inverter, a converter or a DC-DC converter. In such a power semiconductor module, electronic circuits are used which can include, among other things, transistors, e.g. insulated-gate bipolar transistors (IGBTs), diodes, triacs or thyristors. To contact the electronic circuits of the power semiconductor module, contacts, so-called pins, are usually provided which lead out from the housing. The pins can be connected to the electronic circuit in the housing by wire bonding, among other methods.One common method, for example, is ultrasonic wire bonding, in which a bonding wire is welded to the bonding surface of a pin using pressure and ultrasonic vibrations. The bonding process, especially with ultrasonic wire bonding, can induce unwanted vibrations in the area of ​​the bonding surfaces of the pins, for example, due to resonances, so that a weld between the bonding wire and the bonding surface of a pin is not achieved or is not achieved with the required quality.

[0008] An object of the present invention is therefore to provide a housing part for a semiconductor module which enables reliable wiring.

[0009] This object is achieved according to the invention by a housing part for a semiconductor module with a housing frame which has a support surface and a guide groove running at an angle to the support surface, a pin which is inserted into the guide groove and which has a foot and a shaft running at an angle to the foot, wherein the shaft of the pin is held in a form-fitting manner in the guide groove of the housing frame, and a damping layer via which the foot of the pin is materially connected to the support surface of the housing frame.

[0010] Furthermore, the object is achieved according to the invention by a semiconductor module with at least one such housing part, wherein the housing frame is connected, in particular materially, to a heat sink, wherein an electronic circuit is arranged on the heat sink, which is, in particular, completely enclosed by the housing frame, wherein the base of the pin has a contact surface on a side facing away from the damping layer and wherein the contact surface is connected to the electronic circuit via a wiring element.

[0011] Moreover, the object is achieved according to the invention by a power converter with at least one such semiconductor module.

[0012] Furthermore, the object is achieved according to the invention by a method for producing a semiconductor module comprising the following steps: providing a housing frame which has a support surface and a guide groove running at an angle to the support surface, and a pin which has a foot and a shaft running at an angle to the foot, applying an adhesive elastic material to the support surface of the housing frame, pushing the pin into the guide groove, wherein the shaft of the pin is held in a form-fitting manner in the guide groove of the housing frame and the foot of the pin is connected in a material-to-material manner to the support surface of the housing frame via the adhesive elastic material, curing the adhesive elastic material to form a damping layer via which the foot of the pin is connected in a material-to-material manner to the support surface of the housing frame.

[0013] The advantages and preferred embodiments listed below with regard to the housing part can be transferred analogously to the semiconductor module, the power converter and the manufacturing method.

[0014] The invention is based on the idea of ​​enabling reliable wiring of a housing part for a semiconductor module by damping vibrations occurring during a wiring process using a damping layer. Bonding wires or bonding strips, among others, are suitable as wiring elements. Such vibrations occur in a housing part when a pin arranged in a housing frame of the housing part is contacted by a bonding wire or bonding strip that is welded by ultrasonic wire bonding. The pin is made, for example, from a metallic material, in particular by punching and subsequent bending.Such a pin, which has a base and a shaft running at an angle of, for example, 90° to the base, is inserted into a guide groove in the housing frame, wherein the housing frame has a support surface and the guide groove running at an angle to the support surface that corresponds, for example, to the angle of the pin. The housing frame is made in particular from a high-temperature plastic. Such a high-temperature plastic can have a melting point above 240°C. PPS (polyphenylene sulfide), for example, is suitable here. The plastic can be filled with an inorganic material, which in particular contains glass or ceramic. The vibrations that occur, for example, during ultrasonic wire bonding are particularly pronounced with such a high-temperature plastic.

[0015] The base of the pin is connected to the contact surface of the housing frame via an adhesive, elastic material. The adhesive, elastic material can be applied, among other things, in the form of a bead, particularly a continuous bead, in particular an adhesive bead. After the adhesive, elastic material has cured, it forms the damping layer for dampening the vibrations. Furthermore, the base of the pin is firmly bonded to the contact surface of the housing frame via the damping layer. The pin shaft is held in a form-fitting manner in the guide groove of the housing frame. In contrast to potting the pin, it still has play in the direction of the guide groove. Together with the damping of the vibrations by the damping layer, a reliable and durable wire connection to the pin can be formed.

[0016] Another embodiment provides for the damping layer to contain an elastic adhesive, in particular a silicone adhesive. An elastic, particularly permanently elastic, adhesive can be an elastomer, for example. Such layers are not only reliable but also inexpensive to produce. The material used to manufacture the damping layer, or rather its composition, is selected in particular to ensure the highest possible damping for the ultrasonic frequency used for welding.

[0017] Another embodiment provides for the guide groove to be designed as a hammerhead groove or dovetail groove. Such grooves are durable and inexpensive to manufacture, for example, using an injection molding process. Another embodiment provides for the base of the pin to be fully bonded to the damping layer. Such a full-surface bond to the damping layer provides particularly good vibration damping, thus achieving improved reliability.

[0018] Another embodiment provides for the damping layer to be applied in a point-like manner, particularly directly beneath the base of the pin. In particular, the adhesive elastic material for forming the damping layer is applied in a point-like manner. Thus, the damping layer is covered after the pins have been fitted and protected from contaminants, such as fibers.

[0019] Another embodiment provides that at least 90%, in particular at least 95%, of the surface of the damping layer is located under the base of the pin. This saves adhesive and prevents contamination particularly efficiently.

[0020] Another embodiment provides for the housing part to have at least two pins, each inserted into a guide groove and connected to the support surface of the housing frame via a separate damping layer. For example, at least two pins are arranged adjacent or next to each other without their damping layers touching each other. This ensures optimal vibration suppression during every wiring process.

[0021] Another embodiment provides for the guide groove to have a continuous opening toward the support surface. The opening is designed, for example, as a gap with a constant width, which is arranged, in particular, perpendicular to the support surface. Such a continuous opening enables simple and cost-effective insertion of the pins.

[0022] A further embodiment provides for the housing frame to be constructed in one piece. Such a one-piece housing frame can be manufactured cost-effectively, for example, from a plastic, in particular a high-temperature plastic, in particular by injection molding. In particular, in combination with the guide grooves open towards the support surface, particularly simple and cost-effective production is enabled. A further embodiment provides for the shaft of the pin to have a fastening profile arranged on both sides, which is configured to hold the pin in the guide groove in a form-fitting manner. The fastening profile can, among other things, include at least one flag-like widening of the shaft on both sides, in particular a symmetrically arranged one. In particular, the pin is designed to be axially symmetrical. By means of such a fastening profile, the pin is held upright in the guide groove.

[0023] Another embodiment provides for the guide groove to be arranged essentially perpendicular to the support surface, and the shaft to be arranged essentially perpendicular to the base of the pin. Such an arrangement enables optimized force transmission with minimal stress on the damping layer when the pin shaft is externally contacted, thus enabling a long service life of the assembly.

[0024] In the following, the invention is described and explained in more detail with reference to the embodiments shown in the figures.

[0025] They show:

[0026] FIG 1 schematic flow diagram of a method for producing a housing part for a semiconductor module,

[0027] FIG 2 a schematic three-dimensional representation of a pin,

[0028] FIG 3 is a schematic longitudinal section of a semiconductor module with a housing part,

[0029] FIG 4 is a schematic cross-sectional view of a section of the semiconductor module in the area of ​​a pin,

[0030] FIG 5 is a schematic diagram of a power converter.

[0031] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0032] The same reference symbols have the same meaning in the different figures.

[0033] FIG 1 shows a schematic flow diagram of a method for producing a housing part 2 for a semiconductor module. The method comprises providing A a housing frame 4 and a pin 6. The housing frame 4 is designed in one piece and made of a plastic, in particular a high-temperature plastic. Such a high-temperature plastic can have a melting point above 240°C. PPS (polyphenylene sulfide), for example, can be used here. The plastic can be filled with another material, in particular an inorganic material which contains, for example, a glass or a ceramic. The housing frame 4 has a support surface 8 and guide grooves 10 which run at an angle (p) to the support surface 8 and are designed, for example, as hammerhead grooves. The support surface 8 defines an xy plane, wherein the guide grooves 10 are arranged perpendicular to the xy plane in the z direction.The guide grooves 10 each have a continuous opening 11 towards the support surface 8. The openings 11 are designed, for example, as a gap with a constant width, each of which is arranged perpendicular to the support surface 8. The pins 6 each have a base 12 and a shaft 14 running essentially perpendicular to the base 12. The pins 6 are made of a metallic material, for example by punching and subsequent bending. The method further comprises applying B an adhesive, elastic material 16 to the support surface 8 of the housing frame 4. The adhesive, elastic material 16 contains, for example, an elastic, in particular permanently elastic, adhesive such as a silicone adhesive.

[0034] Furthermore, the method comprises inserting C each pin 6 into one of the guide grooves 10, wherein during insertion C the base 12 of the pin 6 is connected to the support surface 8 of the housing frame 4 via the adhesive elastic material 16. The insertion C of the pins 6 into the guide groove 10 occurs from a side facing away from the support surface 8, i.e. in the -z direction. The adhesive elastic material 16 is provided for the integral connection of the pin 6 to the support surface 8. The adhesive elastic material 16 is applied in a point-like manner directly beneath the base 12 of the respective pin 6. The shafts 14 of the pins 6 each have a fastening profile 18 arranged on both sides. The fastening profile 18 is designed to correspond to the guide groove 10, whereby the pins 6 are held in the respective guide groove 10 in a form-fitting manner in the x and y directions via the fastening profiles 18 after insertion C.For example, the fastening profile 18 is designed as a symmetrical flag-like widening of the shaft 14.

[0035] Furthermore, the method comprises curing D of the adhesive elastic material 16 to form a damping layer 20, via which the base 12 of the pin 6 is integrally connected to the support surface 8 of the housing frame 4. Curing D takes place thermally, for example by means of infrared radiation or induction. When inserting C the pins 6, the respective base 12 is pressed onto the adhesive elastic material 16 applied in a point-like manner directly beneath the base 12 of the respective pin 6 in such a way that after curing D at least 90%, in particular at least 95%, of the surface of the damping layer 20 is located beneath the base 12 of the pin 6 and the damping layers 20 of the pins 6 do not touch each other.To achieve such a covering, a groove, in particular a circumferential groove, can be introduced in the area of ​​the surface of the damping layer 20 in the support surface 8, which groove serves to accommodate an excess adhesive elastic material 16. Additionally or alternatively, such a groove can be introduced into a surface of the base 12 of the pin 6 facing the support surface 8.

[0036] In this way, a separate damping layer 20 is formed beneath each of the pins 6, which firmly connects the pins 6 to the support surface 8. Furthermore, the damping layer 20, which has not yet fully cured, is covered after the pins 6 have been populated and protected from contamination, e.g., fibers. By arranging the pin 6 in the guide groove 10, the pin 6 has a certain amount of play in the z-direction, depending on the damping layer 20.

[0037] FIG 2 shows a schematic three-dimensional representation of a pin 6, which is axially symmetrical and corresponds to the design in FIG 1.

[0038] FIG 3 shows a schematic sectional view of a semiconductor module 22 with a housing part 2, which is manufactured as shown in FIG 1. The housing frame 4 is materially connected, e.g. by gluing, to a heat sink 24, which is designed as a metallic base plate, for example. The heat sink 24 can alternatively be designed, among other things, as a heat sink. An electronic circuit 26 is arranged on the base plate and is completely enclosed by the housing frame 4. The electronic circuit 26 comprises a substrate 28, on which semiconductor elements 30 are materially connected, wherein the substrate 28 is connected to the metallic base plate on a side facing away from the semiconductor elements 30. The substrate 28 comprises a dielectric material layer that is metallized on both sides and contains a ceramic material, for example aluminum nitride or aluminum oxide, or an organic material, for example a polyamide.The dielectric material layer can have a thickness of 25 pm to 600 pm, in particular 50 pm to 320 pm. The semiconductor elements 30 can comprise at least one, in particular vertical, transistor, in particular an insulated-gate bipolar transistor (IGBT). Furthermore, at least one transistor can be assigned a diode, in particular connected in antiparallel. The integral connection of the semiconductor elements 30 to the substrate 28 can be produced, inter alia, by soldering and / or sintering.

[0039] In particular, the pins 6 are designed essentially identically. A contacting region 32 of the shaft 14 of the pins 6 is configured to establish a connection, e.g., a soldered connection or press-fit connection, to a printed circuit board. The feet 12 of the pins 6 each have a contacting surface 34, which is designed, for example, as a bonding surface. The contacting surface 34 is configured to establish an electrical connection between the pin 6 and at least one of the semiconductor elements 30, wherein the electrical connection can be made directly to the semiconductor element 30 or via the substrate 28. Wiring elements 36 are used for the electrical connection, which, in FIG. 3, are connected to the substrate 28 starting from the contacting surface 34 of the respective pin 6. Further wiring elements 36 are connected to wiring surfaces 38 of the semiconductor elements 30.The wiring elements 36 can be implemented, among other things, as bonding wires or bonding strips, which are welded to the respective surface using an ultrasonic wire bonding process. Vibrations occurring during the production of such a bond connection are at least partially dampened by the damping layer 20 arranged between the base 12 of the pin 6 and the support surface 8 of the housing frame 4. The further design of the housing part 2 in FIG. 3 corresponds to that in FIG. 1.

[0040] FIG 4 shows a schematic cross-sectional view of a section of the semiconductor module 22 in the area of ​​a pin 6. The design of the semiconductor module 22 corresponds to that in FIG 3.

[0041] FIG 5 shows a schematic representation of a power converter 40, which comprises a semiconductor module 22 having a housing part 2. The power converter 40 can comprise more than one semiconductor module 22.

[0042] In summary, the invention relates to a housing part 2 for a semiconductor module 22. In order to enable reliable wiring, it is proposed that the housing part 2 comprises the following components: a housing frame 4, which has a support surface 8 and a guide groove 10 running at an angle (p) to the support surface 8, a pin 6 inserted into the guide groove 10, which pin 6 has a foot 12 and a shaft 14 running at an angle (p) to the foot 12, wherein the shaft 14 of the pin 6 is held in a form-fitting manner in the guide groove 10 of the housing frame 4, and a damping layer 20, via which the foot 12 of the pin 6 is materially connected to the support surface 8 of the housing frame 4.

Claims

Patent claims 1. Housing part (2) for a semiconductor module (22) with - a housing frame (4) which has a support surface (8) and a guide groove (10) extending at an angle (cp) to the support surface (8), - a pin (6) inserted into the guide groove (10), which has a base (12) and a shaft (14) extending at an angle (cp) to the base (12), wherein the shaft (14) of the pin (6) is held in a form-fitting manner in the guide groove (10) of the housing frame (4), and - a damping layer (20) via which the base (12) of the pin (6) is integrally connected to the support surface (8) of the housing frame (4).

2. Housing part (2) according to claim 1, wherein the damping layer (20) contains an elastic adhesive, in particular a silicone adhesive.

3. Housing part (2) according to one of claims 1 or 2, wherein the guide groove (10) is designed as a hammer head groove or dovetail groove.

4. Housing part (2) according to one of the preceding claims, wherein the base (12) of the pin (6) is fully connected to the damping layer (20).

5. Housing part (2) according to one of the preceding claims, wherein the damping layer (20) is applied selectively, in particular directly under the base (12) of the pin (6).

6. Housing part (2) according to claim 5, wherein at least 90%, in particular at least 95%, of the surface of the damping layer (20) is located under the base (12) of the pin (6).

7. Housing part (2) according to one of the preceding claims, comprising at least two pins (6), each of which is inserted in a guide groove (10) and is connected to the support surface (8) of the housing frame (4) via a separate damping layer (20).

8. Housing part (2) according to one of the preceding claims, wherein the guide groove (10) has a through opening (11) towards the support surface (8).

9. Housing part (2) according to one of the preceding claims, wherein the housing frame (4) is made in one piece.

10. Housing part (2) according to one of the preceding claims, wherein the shaft (14) of the pin (6) has a fastening profile (18) arranged on both sides, which is configured for the positive holding of the pin (6) in the guide groove (10).

11. Housing part (2) according to one of the preceding claims, wherein the guide groove (10) is arranged substantially perpendicular to the support surface (8) and the shaft (14) is arranged substantially perpendicular to the base (12) of the pin (6).

12. Semiconductor module (22) with at least one housing part (2) according to one of the preceding claims, wherein the housing frame (4) is connected, in particular materially bonded, to a heat sink (24), wherein an electronic circuit (26) is arranged on the heat sink (24) and is, in particular, completely enclosed by the housing frame (4), wherein the base (12) of the pin (6) has a contacting surface (34) on a side facing away from the damping layer (20), and wherein the contacting surface (34) is connected to the electronic circuit (26) via a wiring element (36).

13. Power converter (40) with at least one semiconductor module (22) according to claim 12.

14. A method for producing a semiconductor module (22) comprising the following steps: - Providing (A) a housing frame (4) which has a support surface (8) and a guide groove (10) extending at an angle (cp) to the support surface (8), and a pin (6) which has a base (12) and a shaft (14) extending at an angle (cp) to the base (12), - applying (B) an adhesive elastic material (16) to the support surface (8) of the housing frame (4), - Inserting (C) the pin (6) into the guide groove (10), whereby the shaft (14) of the pin (6) is held in a form-fitting manner in the guide groove (10) of the housing frame (4) and the base (12) of the pin (6) is connected to the support surface (8) of the housing frame (4) via the adhesive elastic material (16), - Curing (D) of the adhesive elastic material (16) to form a damping layer (20) via which the base (12) of the pin (6) is firmly bonded to the support surface (8) of the housing frame (4).

15. The method according to claim 14, wherein the base (12) of the pin (6) is bonded over its entire surface to the adhesive elastic material (16).

16. Method according to one of claims 14 or 15, wherein the application (B) of the adhesive elastic material (16) takes place selectively, in particular directly under the base (12) of the pin (6).

17. Method according to claim 16, wherein during insertion (C) of the pin (6) its foot (12) is pressed onto the adhesive elastic material (16) in such a way that after curing (D) at least 90%, in particular at least 95%, of the surface of the damping layer (20) is located under the foot (12) of the pin (6).

18. The method according to claim 17, wherein in the region of the surface of the damping layer (20) a groove, in particular a circumferential groove, is introduced into the support surface (8) and / or into a surface of the base (12) of the pin (6) facing the support surface (8), which groove is configured to receive an excess adhesive elastic material (16).

19. Method according to one of claims 14 to 18, wherein the curing (D) takes place thermally, in particular by means of infrared radiation and / or induction.

20. Method according to one of claims 17 to 19, wherein the housing frame (4) is connected, in particular materially, to a heat sink (24), wherein an electronic circuit (26) is arranged on the heat sink (24), which is, in particular, completely enclosed by the housing frame (4), wherein the base (12) of the pin (6) has a contacting surface (34) on a side facing away from the damping layer (20), and wherein the contacting surface (34) is connected to the electronic circuit (26) via a wiring element (36).

21. Method according to one of claims 17 to 20, wherein the guide groove (10) has a through opening (11) towards the support surface 8, wherein the insertion (C) of the pin (6) into the guide groove (10) takes place from a side facing away from the support surface (8).

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