Gel-filled power module with a circuit carrier

Abstract

Power module (12) with a circuit carrier comprising a carrier substrate and an electrical insulation layer, wherein the circuit carrier has a first conductor structure with an external contact region and at least one second conductor structure with at least one external contact region and a further, third conductor structure which comprises at least one external contact region, with semiconductor components (42) arranged individually or in groups, characterized in that a multifunctional frame (50) and a frame (56) are assigned to the power module (12), wherein the groups of semiconductor components (42) are arranged in a first plane (60) which is spatially separated from a second plane (62) in the multifunctional frame (50), wherein the semiconductor components (42) are connected by a first sintered connection (130) with the introduction of at least one first spacer (100).1) or are electrically connected to one another by a bond connection by introducing at least one bond wire, wherein the second plane (62) is at least partially enclosed laterally by the frame (56) and is filled with a gel mass (112).

Description

Technical area

[0001] The invention relates to a power module with a circuit carrier comprising a carrier substrate and an electrical insulation layer. The circuit carrier has a first conductor structure with an external contact area, at least one second conductor structure with at least one external contact area, and a further, third conductor structure comprising at least one external contact area. State of the art

[0002] In the current state of the art, power modules, for example, those installed in a power module bridge, are additionally molded. During molding, the power module is embedded in a rigid protective housing, for example, made of plastic (molding compound). The molding compound serves to enclose and protect the interior of the power module. However, these molding compound enclosures of the power module are not particularly resistant to cracking.

[0003] From DE 11 2017 004 390 T5 a power module is known which has the following features: an insulating substrate having a front side to which a power semiconductor element is attached; a base plate connected to a back side of the insulating substrate; a housing attached to the base plate and surrounding the insulating substrate; a cover attached to the housing and forming a sealed area; and a silicone gel serving as a filling element which fills the entire sealed area and has an internal stress acting as a compressive stress.

[0004] DE 10 2014 219 998 B4 discloses a power module, in particular for providing a phase current for an electric motor. The power module comprises a circuit carrier with a surface, at least two first contact surfaces on the surface, and at least two first power transistors, each of which has a ground contact surface. A first power transistor of the at least two first power transistors is arranged directly on each of the first contact surfaces and is electrically conductively connected to the respective first contact surface via its ground contact surface. Furthermore, the power module comprises a second contact surface on the surface and at least two second power transistors, each of which has a ground contact surface.The at least two second power transistors are arranged directly on the second contact surface and are electrically connected directly to the second contact surface via their respective ground contact surfaces. Furthermore, the power module comprises at least two third contact surfaces on the surface, wherein the at least two second power transistors each have a further contact surface on their sides facing away from the surface of the circuit carrier, and a second power transistor of the at least two second power transistors is electrically connected to one of the at least two third contact surfaces via its further contact surface.The at least two first contact surfaces and the at least two third contact surfaces are arranged alternately one after the other in a longitudinal direction of the power module, and the second contact surface is arranged next to the at least two first contact surfaces and the at least two third contact surfaces, the second contact surface having at least two contact regions, one of the at least two contact regions being located next to each of the at least two first power transistors. The at least two first power transistors each have a further contact surface on their sides facing away from the surface of the circuit carrier, and a first power transistor of the at least two first power transistors is electrically conductively connected via its further contact surface to the respective contact region of the at least two contact regions of the second contact surface located next to it.Here, the at least two contact regions of the second contact surface and the at least two second power transistors are arranged alternately one after the other in the longitudinal direction.

[0005] EP 2 418 925 B1 discloses an electrical contact between a flexible foil having at least one conductor track and at least one electrical contact of a sensor or control device. An end section of the flexible foil is electrically contacted at a contact point by heat input, with the end section of the flexible foil being positioned against protruding electrical contacts at the contact point. The end section of the flexible foil is designed as a waveguide, in particular as a deflection element. Disclosure of the invention

[0006] According to the invention, a power module is proposed with a circuit carrier comprising a carrier substrate and an electrical insulation layer, wherein the circuit carrier comprises a first conductor structure with an external contact region and at least one second conductor structure with at least one external contact region and a further, third conductor structure which has at least one external contact region, with semiconductor components which are arranged individually or in groups, in such a way that a multifunctional frame and a frame are assigned to the power module, wherein the groups of semiconductor components are arranged in a first plane which is spatially separated from a second plane in the multifunctional frame, wherein the semiconductor components are electrically connected to one another by a sintered connection with the introduction of at least one first spacer or by a bonding connection with the introduction of at least one bonding wire,wherein the second level is at least partially enclosed laterally by the frame and is filled with a gel mass,

[0007] A particularly advantageous structure is created by the solution according to the invention by filling the power module with a gel mass. In this case, the power module or multiple power modules are not typically enclosed with a molding compound, but are attached to the cooling surface without a molding compound. A frame is attached around the power module to the cooling surface, and the volume enclosed by the frame is filled with the gel mass such that one or more power modules are covered with gel. A silicone gel is a semi-solid substance containing a network of silicone polymers suspended in a liquid or viscous medium. Silicone gel is temperature-resistant and does not deform its structure. In contrast to a potting compound, such as a casting compound, the gel has high elasticity and flexibility and is therefore able to absorb and distribute thermal stresses without cracking or breaking.In addition, silicone gel has a lower thermal conductivity coefficient, which improves insulation and helps limit local temperature differences.

[0008] In a further advantageous embodiment of the power module proposed according to the invention, the semiconductor components are arranged individually or in groups on a base of the power module.

[0009] In the power module proposed according to the invention, the spacer is arranged in the region of a joint between an underside of the multifunctional frame and an upper side of the power module. Component tolerances and / or manufacturing tolerances that arise when joining the relevant components can be compensated for via the at least one spacer provided within the at least one sintered connection. Furthermore, the installation of spacers in a power module can prevent short circuits. Furthermore, the installation of spacers provides optimal heat dissipation, which leads to improved performance and reliability of the power module. Furthermore, spacers are coupled to semiconductor switches and circuit boards, for example, using sintered connections.One advantage of the sintered joint is that it eliminates the need for additional fasteners such as screws, adhesives, or welds, eliminating the weak points or sources of failure associated with such fasteners. Furthermore, the sintered joint achieves a homogeneous stress distribution among the power module components, as the stresses are evenly distributed across the entire joining surface. This reduces stress concentrations and improves the overall stability of a joint.

[0010] In a further advantageous embodiment of the power module proposed according to the invention, the spacer is arranged in the region of a joint between a bottom side of the multifunctional frame and a top side of the power module.

[0011] In a further advantageous embodiment of the power module proposed according to the invention, the sintered connection has a first, a second and a third sintered layer.

[0012] In a further advantageous embodiment of the power module proposed according to the invention, the first sintered connection can be replaced by a first welded connection or a first soldered connection, wherein in both cases a structural unit with a first, second and third layer is created.

[0013] In a further advantageous embodiment of the power module proposed according to the invention, the power module has a second sintered connection.

[0014] In a further advantageous embodiment of the power module proposed according to the invention, the second sintered connection has a fourth and a fifth sintered layer.

[0015] In a further advantageous embodiment of the power module proposed according to the invention, the second sintered connection can be replaced by a second welded connection or a second soldered connection, wherein in both cases a structural unit with the first and the second layer is created.

[0016] In a further advantageous embodiment of the power module proposed according to the invention, the power module is connected to a cooling surface via a third solder connection, an adhesive connection or a third sintered connection.

[0017] In a further advantageous embodiment of the power module proposed according to the invention, the multifunctional frame is arranged above or below the power module as seen in the Z direction.

[0018] In a further advantageous embodiment of the power module proposed according to the invention, current-carrying components, in particular a T+ bridge and a T- bridge, are formed one above the other or next to each other in the multifunctional frame in such a way that a low-inductive connection is formed. Advantages of the invention

[0019] In the power module according to the invention, the multifunctional frame and the power module are separated from one another in the Z direction and electrically connected to one another by a material-to-material connection, which is preferably designed as a soldered or welded connection. The current-carrying contact surfaces preferably extend in a multifunctional frame that can be placed above or below the power module, while the semiconductor components, which are arranged individually or in groups on the underside of the power module, are placed therein. The cooling surface is positioned in such a way that it is ensured that the area with the highest heat loss, in particular the underside of the power module, receives the necessary cooling. This ensures that the cooling surface remains thermally connected throughout the entire process.Furthermore, the solder joint enables efficient unevenness compensation to compensate for any unevenness and / or irregularities between the surface of the power module and the cooling surface, achieving an improved contact area and thus optimized heat transfer. Furthermore, the solder joint exhibits low electrical conductivity compared to some other joining materials, which advantageously prevents short circuits in an electrically insulating connection.

[0020] The introduction of spacers advantageously ensures efficient alignment and placement of the power module components while simultaneously optimizing heat dissipation. The power module according to the invention is characterized by the fact that a sintered connection of the spacers achieves optimized structural strength between the components of the power module and the multifunctional frame, whereby the sintered connection effectively dampens vibrations, shocks, and / or other mechanical loads. Furthermore, the sintered connection achieves precise shaping of the connections, ensuring correct alignment and positioning, thus compensating for component or manufacturing tolerances.

[0021] According to the invention, the power module is advantageously connected to the multifunction frame via the bond connection, the first welded connection, the first sintered connection, or a first soldered connection. The soldered, bonded, and welded connections achieve an efficient connection such that, for example, surface irregularities of the power module and / or the multifunction frame are compensated for by these connection types. Furthermore, the soldered connection and the welded connection can ensure a mechanically strong connection. Furthermore, the soldered connection can compensate for differences in thermal expansion between the power module and the multifunction frame in order to effectively prevent potential stresses and cracks due to temperature fluctuations. The alternative bond connection minimizes undesirable effects such as inductance and capacitance, thus ensuring optimized signal integrity and performance.A bonded connection also has good mechanical stability, effectively compensating for vibrations, shock loads and other mechanical stresses.

[0022] Thanks to the advantageously low-inductance current-carrying paths, a significant reduction in switching losses can be achieved. Furthermore, low-inductance paths help minimize voltage spikes to protect the integrity of semiconductor elements and other electronic components, especially in power modules with fast switching operations. Short description of the drawings

[0023] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.

[0024] They show: Fig. 1 a plan view of a first circuit carrier of a power module, which is composed of a carrier substrate and an arrangement of semiconductor components, Fig. 2 a plan view of a power module with separate cooling and layout areas with laterally arranged areas for press-in pins, Fig. 3 an exploded view of an arrangement of power modules, multifunctional frame, gel mass and the cooling surface, Fig. 4 an enlarged view of a first sintered connection, Fig. 5 an enlarged view of a second sintered joint, Fig. 6 an enlarged view of a bond connection. Embodiments of the invention

[0025] In the following description of the embodiments of the invention, identical or similar elements are designated by the same reference numerals, whereby a repeated description of these elements is omitted in individual cases. The figures only schematically illustrate the subject matter of the invention.

[0026] Fig. 1 shows a plan view of a power module 12, in particular of its circuit carrier 14.

[0027] The top view according to Fig. 1 shows that a carrier substrate 40 of the circuit carrier 14 is provided with a number of conductor structures 18, 20A, 20B, 22. The circuit carrier 14 extends in an X,Y plane 10, wherein the circuit carrier 14 is formed with an electrical insulation layer 16. A first conductor structure 18, which has an external contact region 18.2, is located thereon, separated from one another by channel-shaped interruptions. Furthermore, second conductor structures 20A, 20B are located opposite one another on the circuit carrier 14, symmetrical to a central longitudinal axis 24 of the power module 12. Each of the two second conductor structures 20A, 20B comprises an external contact region 20A.2, 20B.2. Finally, a third conductor structure 22 is applied to the circuit carrier 14 or to its electrical insulation layer 16, which has at least one external contact area 22.2.

[0028] The aforementioned conductor structures 18, 20A, 20B, 22 are electrically separated from one another and applied to the circuit carrier 14 essentially symmetrically to the central longitudinal axis 24. AMB (Active Metal Brazing, (OFC (Oxygen-free Copper) / Si3N4 / OFC)) is advantageously selected as the carrier substrate 40 of the circuit carrier 14.

[0029] The representation according to Fig. Figure 2 shows a top view of the power module 12. In this schematic representation, semiconductor components 42 are arranged on active surfaces 36, which may be, for example, transistors, MOSFETs, IGBTs, diodes, or other semiconductor components that can be used as semiconductor switches. Fig. 2 shows that a first group 64 of semiconductor components 42 is accommodated on the active areas 36. The individual semiconductor components 42 can be designed as MOSFETs, for example, and have control terminals 34 on their outer sides, via which a control (not shown in detail) of the individual semiconductor components 42 of the first group 64 of semiconductor components 42 can take place. Analogous to the first group 64, a second group 66 of semiconductor components 42 is arranged, which can also be MOSFETs, with control terminals 34 being formed on their outer region. An arrangement of the semiconductor components 42 in groups 64, 66 is not absolutely necessary; depending on the scaling, they can also be arranged individually, i.e., not in groups 64, 66.The semiconductor components 42 of the second group 66 of semiconductor components 42 can be controlled externally via the control connections 34, which is shown in the illustration according to . Fig. 2 is not shown in detail.

[0030] Furthermore, the plan view according to Fig. 2 shows that in the Fig. 2, areas are provided on the long sides of the circuit carrier 14 in the form of a carrier substrate 40, in which press-in pins 76 - 94 are inserted into the plane of the drawing according to Fig. 2 protrude. Specifically, these are first and second press-in pins 76, 78, third and fourth press-in pins 80, 82, and, arranged opposite one another, fifth and sixth press-in pins 84, 86. In the area of ​​the opposite end face of the circuit carrier 14, seventh and eighth press-in pins 88, 90 are provided, as well as ninth and tenth press-in pins 92, 94.

[0031] Fig. 3 shows an arrangement of the power modules 12, the multifunctional frame 50, the gel mass 112 and the cooling surface 106 with a frame 56, wherein the frame 56 is made of plastic, for example.

[0032] In Fig. 3 shows three power modules 12 positioned within the frame 56, with each power module 12 being assigned a multifunctional frame 50. Fig. 3 further shows an area 113 to be filled with gel mass 112. The area 113 to be filled with gel mass is located within the volume enclosed by the frame 56. The enclosed volume can be influenced, for example, by appropriate dimensions of the frame 56. This can be achieved, for example, by determining the length, width, and depth dimensions of the power modules 12 to be constructed within the frame 56.

[0033] Fig. 4 shows an enlarged view of the first sintered connection 130. The Fig. The first sintered connection 130 shown in Figure 4 has a first sintered layer 122, with which a semiconductor component 42 is connected to the base 96 of the power module 12. Furthermore, the first sintered connection 130 has a second sintered layer 124, with which the semiconductor component 42 is connected to a first spacer 100.1, and a third sintered layer 126, which connects the first spacer 100.1 to a contact strip 146 of the multifunctional frame 50, so that the heat of the contact strips 146 can be dissipated via the third solder connection 110, the adhesive connection 110, or the third sintered connection 133 through the base surface 96 to the cooling surface 106. Fig. The first sintered connection 130 shown in Figure 4 advantageously ensures efficient heat dissipation and electrical reliability. For example, the first, second, and third sintered layers 122, 124, 126 of the first sintered connection 130 are formed using conductive metal powders as the sintered material, such as silver or copper. Excellent electrical and thermal conductivity is achieved by the first sintered connection 130 according to the invention with the electrically conductive material. For example, the first, second, and third sintered layers 122, 124, 126 of the first sintered connection 130 can be applied by applying the electrically conductive metal powder to a surface of the components of the power module 12 or the multifunction frame 50 to be connected to one another.Furthermore, sintered particles of the sintered material, in particular metal powder, can be fused to one another and to the surfaces, for example by controlled heating to an adjusted temperature, to create a solid and thermal bond. Alternatively, the first sintered joint 130 can be replaced by a first welded joint 134 or a first soldered joint 108.

[0034] The Fig. The connection of the base 96 of the power module 12 to the cooling surface 106 shown in Figure 4 can be variably made by a second solder connection 110 (an adhesive connection 110 or a third sintered connection 133). All connections of the base 96 of the power module 12 to the cooling surface 106 are characterized by efficient thermal conduction of the heat dissipated through the base 96 of the contact strip 146. These connection options also offer optimal adaptation to the tolerances of the surface of the power module 12 to be contacted with the cooling surface 106, since a uniform surface contact is ensured by the Fig. 4 shown connection options are available.

[0035] Furthermore, in Fig. 4 shows an arrangement of the first plane 60, the second plane 62, and the cooling surface 106, with the second plane 62 being arranged on the cooling surface 106 and the first plane on the second plane 62. A frame 56 is also shown. The frame 56 surrounds the power module 12 laterally. Furthermore, a frame 56 is shown with a region 113 to be filled, which is filled with gel mass 112.

[0036] The Fig. 5 shows an enlarged view of the second sintered connection 132.

[0037] The Fig. The second sintered connection 132 shown in Figure 5 comprises the fifth sintered layer 129, with which a second spacer 100.2 is connected to the underside of the phase bridge 136, and the fourth sintered layer 128, with which the second spacer 100.2 is connected to the bottom 96 of the power module 12. The second spacer 100.2 is located on the bottom 96 of the power module 12, so that the heat of the phase bridge 136 can be dissipated through the bottom surface 96 via the third sintered connection 133, or the solder or adhesive connection 110, to the cooling surface 106. Alternatively, the second sintered connection 132 can be replaced by a second welded connection 136 or a second soldered connection 109. Fig. 5 also shows the filling of the second level 62 with gel mass 112.

[0038] Fig. 6 shows an enlarged view of a bond connection 142.

[0039] The Fig.The bond connection 142 shown in Figure 6 comprises an electrical connection of the semiconductor components 42 of the power module 12 to the multifunction frame 50 via the bond wires 140. Alternatively to introducing the spacers 100.1, 100.2, the bond wires 140 are attached to a contact surface 102 of the semiconductor component 42 of the power module 12 and to the connection pads 138 of the multifunction frame 50. Alternatively, an electrical connection between the semiconductor elements 42 of the power module 12 and the multifunction frame 50 can also be established by introducing the printed circuit board and the bond connection 142.

[0040] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of one skilled in the art. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 11 2017 004 390 T5

[0003] DE 10 2014 219 998 B4

[0004] EP 2 418 925 B1

[0005]

Claims

[1] Power module (12) with a circuit carrier (14) comprising a carrier substrate (40) and an electrical insulation layer (16), wherein the circuit carrier (14) has a first conductor structure (18) with an external contact area (18.2) and at least one second conductor structure (20A, 20B) with at least one external contact area (20A.2, 20B.2) and a further, third conductor structure (22) comprising at least one external contact area (22.2), with semiconductor components (42) arranged individually or in groups (64, 66), characterized byin that a multifunctional frame (50) and a frame (56) are assigned to the power module (12), wherein the groups (64, 66) of semiconductor components (42) are arranged in a first plane (60) which is spatially separated from a second plane (62) in the multifunctional frame (50), wherein the semiconductor components (42) are electrically connected to one another by a first sintered connection (130) with the introduction of at least one first spacer (100.1) or by a bond connection (142) with the introduction of at least one bond wire (140), wherein the second plane (62) is at least partially enclosed laterally by the frame (56) and is filled with a gel mass (112). [2] Power module (12) according to claim 1, characterized by that the semiconductor components (42) are arranged individually or in groups (64, 66) on a base (96) of the power module (12). [3] Power module (12) according to claims 1 and 2, characterized bythat the spacer (100.1, 100.2) is arranged in the region of a joint between a bottom side (120) of the multifunctional frame (50) and a top side of the power module (12). [4] Power module (12) according to claims 1 to 3, characterized by that the first sintered connection (130) has a first, a second and a third sintered layer (122, 124, 126). [5] Power module (12) according to claims 1 to 4, characterized by that the first sintered connection (130) can be replaced by a first welded connection (134) or a first soldered connection (108), in both cases a structural unit with the first, second and third layers being formed. [6] Power module (12) according to claims 1 to 5, characterized by that the power module (12) has a second sintered connection (132). [7] Power module (12) according to claims 1 to 6, characterized bythat the second sintered connection (132) has a fourth and a fifth sintered layer (128, 129). [8] Power module (12) according to claims 1 to 7, characterized by that the second sintered connection (132) can be replaced by a second welded connection (136) or a second soldered connection (109), in both cases forming a structural unit with the first and second layers. [9] Power module (12) according to claims 1 to 6, characterized by that the power module (12) is connected to a cooling surface (106) via a third solder connection, an adhesive connection (110) or a third sintered connection (133). [10] Power module (12) according to claims 1 to 7, characterized by that the multifunctional frame (50) is arranged above or below the power module (12) as seen in the Z direction (54). [11] Power module (12) according to claims 1 to 8, characterized bythat current-carrying components, in particular a T+ bridge and a T- bridge, are formed one above the other or next to each other in the multifunctional frame (50) in such a way that a low-inductive connection is formed.

Images