Power module packaging structure

Abstract

The utility model provides a power module packaging structure. The power module packaging structure comprises a heat dissipation bottom plate; the direct copper-clad ceramic substrate is arranged on the heat dissipation bottom plate, and the direct copper-clad ceramic substrate is provided with a first group of power terminals and a second group of power terminals which are partially overlapped and are used for guiding reverse current; the middle frame is fixedly connected with the heat dissipation bottom plate so that the direct copper-clad ceramic substrate can be connected in the middle frame in a sleeved mode, and the direct copper-clad ceramic substrate leads out the first set of power terminals and the second set of power terminals to the side away from the heat dissipation bottom plate through the middle frame. A signal terminal is also arranged on one side, deviating from the heat dissipation bottom plate, of the middle frame; the signal terminal is electrically connected with a signal connecting end of the direct copper-clad ceramic substrate through a bonding wire; the cover plate is arranged on the side, away from the heat dissipation bottom plate, of the middle frame so that the direct copper-clad ceramic substrate can be sealed in the middle frame. The anti-vibration capability of the device can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the field of power device packaging, in particular to a power module packaging structure. Background Art

[0002] Power semiconductor devices, as core components in power electronic converters, are currently widely used in new energy system inverters, battery management, electric drive systems, and frequency converters. Third-generation semiconductor chips such as silicon carbide and gallium nitride have become the optimal choice for high-power power electronic converter systems due to their higher switching frequencies and power densities. This also places higher demands on the power semiconductor chip packaging structure and packaging process. Excessive parasitic inductance can cause voltage spikes and current oscillations, especially during fast switching operations, which can increase device stress and cause overvoltage failure. Furthermore, parasitic inductance can increase electromagnetic interference (EMI), affecting the system's electromagnetic compatibility and reducing system stability and reliability. Utility Model Content

[0003] In view of the above problems existing in the prior art, the present invention proposes a power module packaging structure, which mainly solves the problems of large switching loss and poor vibration resistance of existing power devices.

[0004] In order to achieve the above-mentioned purpose and other purposes, the technical solution adopted by the present utility model is as follows.

[0005] The present application provides a power module packaging structure, comprising: a heat dissipation base plate; a direct copper-clad ceramic substrate, which is arranged on the heat dissipation base plate, and is provided with a first group of power terminals and a second group of power terminals that partially overlap and are used to guide reverse current; a middle frame, which is fixedly connected to the heat dissipation base plate to sleeve the direct copper-clad ceramic substrate within the middle frame, wherein the direct copper-clad ceramic substrate leads the first group of power terminals and the second group of power terminals to a side away from the heat dissipation base plate through the middle frame, and a signal terminal is further provided on the side of the middle frame away from the heat dissipation base plate, and the signal terminal is electrically connected to the signal connection end of the direct copper-clad ceramic substrate through a bonding wire; and a cover plate, which is arranged on a side of the middle frame away from the heat dissipation base plate to seal the direct copper-clad ceramic substrate within the middle frame.

[0006] In one embodiment of the present application, the heat dissipation base plate and the middle frame are fixed by screws.

[0007] In one embodiment of the present application, fixing holes are provided on portions of the first group of power terminals and the second group of power terminals exposed from the middle frame.

[0008] In one embodiment of the present application, a nut is provided between the fixing hole and the heat dissipation base plate.

[0009] In one embodiment of the present application, the second group of power terminals includes a positive terminal and a negative terminal, and surfaces of the positive terminal and the negative terminal facing each other form an overlapping structure.

[0010] In one embodiment of the present application, the positive terminal includes a first positive end face, a second positive end face, a third positive end face and a positive pin end; the negative terminal includes a first negative end face, a second negative end face, a third negative end face and a negative pin end; the first positive end face is parallel to the second positive end face, and the third positive end face is connected between the first positive end face and the second positive end face; the first negative end face is parallel to the second negative end face, and the third negative end face is connected between the first negative end face and the second negative end face; wherein, the first positive end face and the first negative end face are located in the same plane; the third positive end face and the third negative end face are respectively arranged on the side where the first positive end face and the first negative end face are close to each other, and the third positive end face and the third negative end face are arranged opposite to each other and parallel to each other; the second positive end face and the second negative end face are parallel to each other and partially overlap; the positive pin end and the negative pin end are staggered and electrically connected to the direct copper clad ceramic substrate respectively.

[0011] In one embodiment of the present application, the locations where the third positive end face connects with the first positive end face and the second positive end face are all arcuate structures; the locations where the third negative end face connects with the first negative end face and the second negative end face are all arcuate structures.

[0012] In one embodiment of the present application, a support platform is provided on the side of the middle frame facing away from the heat dissipation base plate, and the support platform is provided between the first group of power terminals and the second group of power terminals. The support platform cooperates with the cover plate to form a closed structure that closes one side of the middle frame.

[0013] In one embodiment of the present application, the signal terminal is disposed on the middle frame and is located on a different side from the first group of power terminals and the second group of power terminals. The signal terminal extends out of the middle frame in a direction perpendicular to the heat dissipation base plate.

[0014] In one embodiment of the present application, the direct copper clad ceramic substrate includes a plurality of parallel wiring structures with currents flowing in opposite directions.

[0015] As described above, the power module packaging structure of the present invention has the following beneficial effects.

[0016] The present application can reduce parasitic inductance by partially overlapping the second set of power terminals through the reverse current mutual inductance offset, thereby effectively reducing the generation of voltage overshoot and oscillation, and effectively improving the stability and reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an exploded view of the power module packaging structure in one embodiment of the present application.

[0018] Figure 2 This is a side view of the cooperation structure between the middle frame and the heat dissipation base plate in one embodiment of the present application.

[0019] Figure 3 It is a three-dimensional schematic diagram of the packaging structure in one embodiment of the present application.

[0020] Figure 4 2 is a schematic three-dimensional diagram of the stacking structure of the second group of power terminals in one embodiment of the present application.

[0021] Figure 5 FIG. 1 is a schematic side view of the stacking structure of the second set of power terminals in one embodiment of the present application.

[0022] Figure 6 This is a top view of a power module packaging structure in one embodiment of the present application.

[0023] Description of Figure Numbers:

[0024] 01-heat dissipation base plate; 02-direct copper-clad ceramic substrate; 03-middle frame; 04-cover plate; 05-first group of power terminals; 06-second group of power terminals; 061-negative terminal; 062-positive terminal; 0611-first negative end face; 0612-second negative end face; 0613-third negative end face; 0614-negative pin end; 0621-first positive end face; 0622-second positive end face; 0623-third positive end face; 0624-positive pin end; 07-signal terminal; 08-nut; 09-metal washer; 10-screw; 11-fixing hole; 12-support platform. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features within these embodiments may be combined with one another, unless they conflict.

[0026] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0027] See also Figure 1 , Figure 1 This is an exploded view of a power module packaging structure in one embodiment of the present application. The packaging structure provided in this embodiment of the present application includes: a heat dissipation base plate 01; a direct copper-clad ceramic substrate 02, which is disposed on the heat dissipation base plate 01 and is provided with a first set of power terminals 05 and a second set of power terminals 06 that partially overlap and are used to conduct reverse current; a middle frame 03, which is fixedly connected to the heat dissipation base plate 01 to fit the direct copper-clad ceramic substrate 02 within the middle frame 03, wherein the direct copper-clad ceramic substrate 02 leads the first set of power terminals 05 and the second set of power terminals 06 to a side away from the heat dissipation base plate 01 through the middle frame 03; the side of the middle frame 03 away from the heat dissipation base plate 01 is also provided with a signal terminal 07, which is electrically connected to the signal connection end of the direct copper-clad ceramic substrate 02 via a bonding wire; and a cover plate 04, which is disposed on the side of the middle frame 03 away from the heat dissipation base plate 01 to seal the direct copper-clad ceramic substrate 02 within the middle frame 03. Specifically, the heat dissipation base plate 01 can be made of copper, and the specific thickness can be set and adjusted according to the actual application requirements of the device, and there is no restriction here. The direct copper-clad ceramic substrate 02 can adopt a three-layer structure, with the middle layer being a ceramic layer and the upper and lower layers being copper layers. A first group of power terminals 05 and a second group of power terminals 06 are respectively provided on opposite sides of the direct copper-clad ceramic substrate 02, and each group of power terminals consists of positive and negative terminals. The size of the three-layer structure of the direct copper-clad ceramic substrate 02 can be set to be slightly smaller than the size of the hollowed-out area in the middle frame 03, so that after the middle frame 03 is fixed on the heat dissipation base plate 01, each chip or component in the direct copper-clad ceramic substrate 02 is placed in the external control area of ​​the middle frame 03, and the first group of power terminals 05 and the second group of power terminals 06 are respectively led out from opposite sides of the middle frame 03 to the side facing away from the heat dissipation base plate 01.

[0028] In one embodiment, see Figure 2 , Figure 2 This is a side view of the matching structure of the middle frame 03 and the heat dissipation base plate 01 in one embodiment of the present application. In order to enhance the vibration resistance, the middle frame 03 and the heat dissipation base plate 01 can be fixedly connected by screws 10. Specifically, holes can be punched on the heat dissipation base plate 01, and the screws 10 pass through the holes on the heat dissipation base plate 01 and match with the corresponding screw holes on the middle frame 03, which can reduce the relative displacement of the middle frame 03 and the base plate during vibration, thereby avoiding the risk of the terminal power terminal breaking due to vibration. When the power module is in a high-temperature working condition, the power terminal will expand due to the temperature, and stress will be generated at the connection between the power terminal and the direct copper-clad ceramic substrate 02. Compared with the solution of fixing with rivets, the locking method of screws 10 is more conducive to the release of this part of the stress. The specific punching position and number of the heat dissipation base plate 01 can be set and adjusted according to the actual application requirements, and are not limited here.

[0029] See also Figure 3 , Figure 3 This is a three-dimensional schematic diagram of the packaging structure in one embodiment of the present application. In one embodiment, the portions of the first and second sets of power terminals 05 and 06 that are exposed from the middle frame 03 are provided with fixing holes 11. Nuts 08 are positioned between these fixing holes 11 and the heat sink base plate 01. Bolts and nuts 08 can be used to secure the power terminals to the middle frame 03.

[0030] In one embodiment, taking the heat dissipation base plate 01 as a square, metal gaskets 09 can be set at the four corners of the heat dissipation base plate 01. The metal gaskets 09 pass through the corresponding positions of the middle frame 03 to protect the middle frame 03 from being broken by excessive force during installation and use.

[0031] See also Figure 4 , Figure 4 Schematic diagram of the stacked structure of the second set of power terminals 06 in one embodiment of the present application. In one embodiment, the second set of power terminals 06 includes a positive terminal 062 and a negative terminal 061, and the facing surfaces of the positive terminal 062 and the negative terminal 061 form an overlapping structure.

[0032] See also Figure 5 , Figure 5This is a schematic side view of the stacking structure of the second group of power terminals 06 in one embodiment of the present application. The positive terminal 062 includes a first positive end face 0621, a second positive end face 0622, a third positive end face 0623 and a positive pin end 0624; the negative terminal 061 includes a first negative end face 0611, a second negative end face 0612, a third negative end face 0613 and a negative pin end 0614; the first positive end face 0621 is parallel to the second positive end face 0622, and the third positive end face 0623 is connected between the first positive end face 0621 and the second positive end face 0622; the first negative end face 0611 is parallel to the second negative end face 0612, and the third negative end face 0613 is connected between the first negative end face 0611 and the second negative end face 0612. The first positive end face 0621 and the first negative end face 0611 are located in the same plane; the third positive end face 0623 and the third negative end face 0613 are respectively arranged on the side where the first positive end face 0621 and the first negative end face 0611 are close to each other, and the third positive end face 0623 and the third negative end face 0613 are arranged opposite to each other and parallel to each other; the second positive end face 0622 and the second negative end face 0612 are parallel to each other and partially overlap; the positive pin end 0624 and the negative pin end 0614 are staggered and electrically connected to the direct copper-clad ceramic substrate 02 respectively. The specific area of ​​the overlapping part of the second positive end face 0622 and the second negative end face 0612 can be set and adjusted according to actual needs and is not limited here. This structural setting of the power terminal not only has mutual inductance cancellation in the vertical direction, but also has a mutual inductance cancellation effect caused by reverse current in the horizontal direction, which can greatly reduce parasitic inductance. In one embodiment, the negative pin terminal 0614 may include two groups, and a group of positive pin terminals 0624 is arranged between the two groups of negative pin terminals 0614. The specific number of pins in each group of pin terminals can be set and adjusted according to actual application requirements and is not limited here.

[0033] In one embodiment, the locations where the third positive end surface 0623 connects with the first positive end surface 0621 and the second positive end surface 0622 are all arcuate structures; and the locations where the third negative end surface 0613 connects with the first negative end surface 0611 and the second negative end surface 0612 are all arcuate structures. The specific arc angle of the arcuate structure can be set and adjusted according to actual application requirements and is not limited here.

[0034] See also Figure 6 , Figure 6This is a top view of the power module packaging structure in one embodiment of the present application. A support platform 12 is provided on the side of the middle frame 03 facing away from the heat sink 01. The support platform 12 is positioned between the first set of power terminals 05 and the second set of power terminals 06. The support platform 12 cooperates with the cover plate 04 to form a closed structure that encloses one side of the middle frame 03. The support platform 12 can be a raised edge extending from the inner wall of the middle frame 03. The support platform 12 can also be configured as a stepped structure. The specific structure of the support platform 12 can be configured according to actual application requirements, as long as it can be sealed in conjunction with the cover plate 04.

[0035] See also Figure 2 In one embodiment, the signal terminals 07 are located on the middle frame 03 and on a different side from the first set of power terminals 05 and the second set of power terminals 06. The signal terminals 07 extend out of the middle frame 03 perpendicular to the heat sink 01. The number of signal terminals 07 can be configured and adjusted based on different product requirements. The signal terminals on the direct-copper-clad ceramic substrate 02 can be connected to the signal terminals 07 in the middle frame 03 via jumpers, allowing the signal terminals 07 to be connected to external devices through the middle frame 03.

[0036] In one embodiment, to further reduce the device's parasitic inductance, the routing of the direct-copper-clad ceramic substrate 02 can be specifically designed to leverage the mutual inductance cancellation of opposing currents, thereby reducing parasitic inductance. This direct-copper-clad ceramic substrate 02 includes multiple parallel routing structures with currents flowing in opposite directions. Routes carrying opposing currents in this routing structure are placed as close together as possible to ensure the mutual inductance cancellation effect. The specific routing can be determined based on the actual product circuit layout and is not a limitation here.

[0037] In one embodiment, multiple chips can be placed on a direct-copper-clad substrate based on actual product requirements. The heat sink base plate 01, direct-copper-clad ceramic substrate 02, and chips can be soldered together via solder paste reflow. Finally, sealant can be applied to the interior of the middle frame 03, and the heat sink base plate 01 and middle frame 03 can be secured together using screws 10. The side of the heat sink base plate 01 facing away from the middle frame 03 can contact the heat sink. To ensure good contact between the heat sink base plate 01 and the heat sink, the holes for screws 10 on the heat sink base plate 01 can be wedge-shaped. After the sealant in the middle frame 03 solidifies, ultrasonic bonding of the bond wires and ultrasonic welding of the power terminals can be performed. The power terminals and model terminals are then soldered to the direct-copper-clad ceramic substrate 02. Finally, silicone gel is injected and the cover plate 04 is placed to form the finished power module package structure.

[0038] Based on the technical solutions of the above embodiments of the present application, screws 10 are used to tighten heat sink base plate 01 and middle frame 03, thereby reducing relative displacement between middle frame 03 and heat sink base plate 01 during vibration. This also effectively relieves stress caused by thermal expansion of the power terminals, preventing stress-induced fracture at the connection between the power terminals and the direct-copper-clad ceramic substrate 02. The structural design of the power terminals and the routing of the direct-copper-clad ceramic substrate 02 effectively reduce device parasitic inductance, enhancing device stability and reliability.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A power module packaging structure, characterized in that: include: heat dissipation base plate; A direct copper-clad ceramic substrate, which is arranged on the heat dissipation base plate, and is provided with a first set of power terminals and a second set of power terminals that partially overlap and are used to guide reverse current; a middle frame, which is fixedly connected to the heat dissipation base plate so as to sleeve the direct copper-clad ceramic substrate within the middle frame, wherein the direct copper-clad ceramic substrate leads the first group of power terminals and the second group of power terminals to a side away from the heat dissipation base plate through the middle frame, and a signal terminal is further provided on the side of the middle frame away from the heat dissipation base plate, and the signal terminal is electrically connected to the signal connection end of the direct copper-clad ceramic substrate through a bonding wire; A cover plate is arranged on a side of the middle frame away from the heat dissipation base plate to seal the direct copper clad ceramic substrate in the middle frame.

2. The power module packaging structure according to claim 1, characterized in that: The heat dissipation base plate and the middle frame are fixed by screws.

3. The power module packaging structure according to claim 1, wherein: Parts of the first group of power terminals and the second group of power terminals exposed from the middle frame are provided with fixing holes.

4. The power module packaging structure according to claim 3, characterized in that: Nuts are provided between the fixing holes and the heat dissipation base plate.

5. The power module packaging structure according to claim 1, wherein: The second group of power terminals includes a positive terminal and a negative terminal, and mutually facing surfaces of the positive terminal and the negative terminal form an overlapping structure.

6. The power module packaging structure according to claim 5, characterized in that: The positive terminal includes a first positive end face, a second positive end face, a third positive end face and a positive pin end; the negative terminal includes a first negative end face, a second negative end face, a third negative end face and a negative pin end; the first positive end face is parallel to the second positive end face, and the third positive end face is connected between the first positive end face and the second positive end face; the first negative end face is parallel to the second negative end face, and the third negative end face is connected between the first negative end face and the second negative end face; wherein, the first positive end face and the first negative end face are located in the same plane; the third positive end face and the third negative end face are respectively arranged on the side where the first positive end face and the first negative end face are close to each other, and the third positive end face and the third negative end face are arranged opposite to each other and parallel to each other; the second positive end face and the second negative end face are parallel to each other and partially overlap; the positive pin end and the negative pin end are staggered and electrically connected to the direct copper clad ceramic substrate respectively.

7. The power module packaging structure according to claim 6, characterized in that: The locations where the third positive end face connects with the first positive end face and the second positive end face are all arcuate structures; the locations where the third negative end face connects with the first negative end face and the second negative end face are all arcuate structures.

8. The power module packaging structure according to claim 1, wherein: A support platform is provided on the side of the middle frame away from the heat dissipation base plate. The support platform is provided between the first group of power terminals and the second group of power terminals. The support platform cooperates with the cover plate to form a closed structure that closes one side of the middle frame.

9. The power module packaging structure according to claim 1, wherein: The signal terminals are arranged on the middle frame and are located on different sides from the first group of power terminals and the second group of power terminals. The signal terminals extend out of the middle frame in a direction perpendicular to the heat dissipation base plate.

10. The power module packaging structure according to claim 1, wherein: The direct copper clad ceramic substrate includes a plurality of wiring structures which are parallel to each other and have currents flowing in opposite directions.

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