Power module terminal and power module packaging structure

Abstract

The embodiment of the utility model provides a power module terminal and a power module packaging structure, and relates to the technical field of semiconductor packaging. The power module terminal comprises a terminal main body and a stress buffer plate arranged at the bottom end of the terminal main body, the top end of the terminal main body is configured to partially extend out of the packaging shell and is connected with an external conductive piece, and the stress buffer plate obliquely extends downwards from the bottom end of the terminal main body and is configured to be connected with the double-sided copper-clad ceramic substrate; and an included angle formed between the stress buffer plate and the terminal main body is greater than 90 degrees. Compared with the prior art, the utility model adopts the stress buffer plate with an inclined structure, so that the stress buffer plate and the terminal main body can be arranged at an obtuse angle, and the arrangement mode that the stress buffer plate and the terminal main body are perpendicular to each other is avoided. Under the action of composite stress in the three-dimensional direction, the overall stress is more uniform, the stress concentration degree is remarkably reduced when the overall structure of the power terminal is subjected to the action of the three-dimensional composite stress, and the anti-vibration fatigue capability is improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, and more specifically, to a power module terminal and a power module packaging structure. Background Technology

[0002] Power semiconductor modules are widely used in power electronics, industrial automation, new energy vehicles, high-speed rail, power grid equipment, and aerospace. These modules need to withstand complex mechanical vibrations, thermal cycling, and environmental stresses, especially in high-frequency switching and high-power-density scenarios. During operation, power semiconductor modules are subjected to mechanical vibrations and shocks, which can lead to stress concentration and material fatigue at internal solder joints, bonding wires, packaging materials, and the substrate. Vibration fatigue failure is one of the common failure modes of power modules, affecting equipment stability and increasing maintenance costs. As the power density of modules increases, the requirements for thermal management and mechanical strength become more stringent, placing higher demands on vibration resistance. Especially in new energy vehicles, high-speed rail, and industrial equipment, power modules need to adapt to harsh environmental conditions (such as vibration, shock, and temperature variations). Improving vibration fatigue resistance can extend the service life of power modules and enhance the overall stability and reliability of the system.

[0003] The inventors discovered that traditional power terminals are typically right-angled. The right-angled arc-shaped connection area between the vertical and horizontal planes of these terminals, intended for stress buffering, is prone to metal vibration fatigue fracture under alternating mechanical stress, resulting in a shorter service life. For example... Figure 1 The simulation results also show that when there is a combined stress in the XYZ three-dimensional direction at the right-angle power terminal, the stress concentration area in the arc-shaped region connecting the vertical and horizontal planes will decrease and will be concentrated at the boundary of the arc-shaped region. Moreover, the stress singularity value is large. In actual testing, the external high-frequency stress value will be much higher than the simulation set value. Therefore, cracks are most likely to occur at the stress singularity. Utility Model Content

[0004] The purpose of this utility model is to provide a power module terminal and a power module packaging structure, which have high resistance to vibration fatigue, can effectively avoid fatigue fracture caused by stress concentration, and improve service life.

[0005] The embodiments of this utility model can be implemented as follows:

[0006] In a first aspect, the present invention provides a power module terminal, including a terminal body and a stress buffer plate disposed at the bottom end of the terminal body. The top end of the terminal body is configured to partially extend out of the encapsulation shell and connect to an external conductive component. The stress buffer plate extends obliquely downward from the bottom end of the terminal body and is configured to connect to a double-sided copper-clad ceramic substrate. The included angle between the stress buffer plate and the terminal body is greater than 90°.

[0007] In an optional embodiment, a transition arc edge is formed between the stress buffer plate and the terminal body.

[0008] In an optional embodiment, a welding plate is further provided at the end of the stress buffer plate away from the terminal body, the angle between the welding plate and the stress buffer plate being greater than 0° and less than 90°, and the welding plate being configured to be welded onto the double-sided copper-clad ceramic substrate.

[0009] In an optional embodiment, a transition arc edge is formed between the welding plate and the stress buffer plate.

[0010] In an optional embodiment, the terminal body includes a terminal connecting part and a terminal fixing part, the stress buffer plate is connected to the bottom end of the terminal connecting part, and the terminal fixing part is connected to the top end of the terminal connecting part and is bent together with the terminal connecting part.

[0011] In an optional embodiment, the terminal fixing part is parallel to the welding plate, and the distance L1 between the terminal connecting part and the welding plate is 1 / 5 to 2 / 3 of the distance L2 between the terminal fixing part and the welding plate.

[0012] In an optional embodiment, the top end of the terminal connector is provided with an arc-shaped bend, and the terminal fixing part is connected to the arc-shaped bend.

[0013] Secondly, this utility model provides a power module packaging structure, including a heat dissipation substrate, a packaging shell, a double-sided copper-clad ceramic substrate, multiple power chips, and multiple aforementioned power module terminals. The packaging shell is disposed on the heat dissipation substrate and forms a packaging cavity. The double-sided copper-clad ceramic substrate is disposed on the heat dissipation substrate. The multiple power chips are mounted on the double-sided copper-clad ceramic substrate. The multiple power module terminals are sequentially spaced on the double-sided copper-clad ceramic substrate. The multiple stress buffer plates are all accommodated in the packaging cavity and connected to the double-sided copper-clad ceramic substrate. The top ends of the multiple terminal bodies partially extend out of the packaging shell and are configured to connect to external conductive components.

[0014] In an optional embodiment, the double-sided copper-clad ceramic substrate is further provided with a first signal terminal and a second signal terminal, a plurality of power chips are arranged in parallel, and the drains of the plurality of power chips are electrically connected to at least one of the power module terminals, the sources of the plurality of power chips are electrically connected to the remaining power module terminals and the first signal terminal, and the gates of the plurality of power chips are electrically connected to the second signal terminal.

[0015] In an optional embodiment, the double-sided copper-clad ceramic substrate includes at least one copper-clad substrate, the copper-clad substrate having a source region, a drain region and a gate region that are electrically separated from each other, and the source region and the drain region are each connected to at least one of the power module terminals.

[0016] Multiple power chips are disposed with their drains facing downwards in the drain region, so that the drains of the multiple power chips are electrically connected to the power module terminals in the drain region.

[0017] The sources of the multiple power chips are respectively connected to the source region through multiple first conductive elements, so that the sources of the multiple power chips are electrically connected to the power module terminal of the source region, and the source region is connected to the first signal terminal through a second conductive element, so that the sources of the multiple power chips are electrically connected to the first signal terminal.

[0018] The gate region is located between the source region and the drain region. The gate region is provided with a plurality of gate resistors. The gates of the plurality of power chips are respectively connected to the gate region through the plurality of gate resistors. The gate region is connected to the second signal terminal through a third conductive element, so that the gates of the plurality of power chips are electrically connected to the second signal terminal.

[0019] In an optional embodiment, a plurality of Schottky barrier diodes are further disposed on the double-sided copper-clad ceramic substrate, the cathodes of the plurality of Schottky barrier diodes being electrically connected to the drains of the plurality of power chips, and the anodes of the plurality of Schottky barrier diodes being correspondingly connected to the sources of the plurality of power chips.

[0020] In an optional embodiment, the double-sided copper-clad ceramic substrate includes a copper-clad substrate, which has a source region, a drain region, a gate region and a Kelvin source region that are electrically separated from each other, and the source region and the drain region are each connected to at least one of the power module terminals.

[0021] Multiple power chips are disposed with their drains facing downwards in the drain region, so that the drains of the multiple power chips are electrically connected to the power module terminals in the drain region.

[0022] The plurality of Schottky barrier diodes are all mounted with their cathodes facing downwards in the drain region, so that the cathodes of the plurality of Schottky barrier diodes are electrically connected to the power module terminals in the drain region;

[0023] The sources of the multiple power chips and the anodes of the multiple Schottky barrier diodes are respectively connected to the source region through multiple first conductive elements, so that the sources of the multiple power chips and the anodes of the multiple Schottky barrier diodes are electrically connected to the power module terminals of the source region. The Kelvin sources of the multiple power chips are connected to the Kelvin source region, and the Kelvin source region is connected to the first signal terminal through a second conductive element, so that the Kelvin sources of the multiple power chips are electrically connected to the first signal terminal.

[0024] The gate region is located between the source region and the drain region. The gates of the plurality of power chips are respectively connected to the gate region through a third conductive element. The gate region is connected to the second signal terminal through a fourth conductive element, so that the gates of the plurality of power chips are electrically connected to the second signal terminal.

[0025] In an optional embodiment, the double-sided copper-clad ceramic substrate is further provided with a negative temperature coefficient thermistor, a third signal terminal and a fourth signal terminal, and the two ends of the negative temperature coefficient thermistor are electrically connected to the third signal terminal and the fourth signal terminal, respectively.

[0026] The beneficial effects of the power module terminals and power module packaging structure provided in this embodiment of the utility model include:

[0027] The power module terminal provided in this embodiment of the invention features a stress buffer plate at the bottom of the terminal body, while the top is partially extended from the encapsulation shell and connected to an external conductive component. The stress buffer plate extends downwards at an angle from the bottom of the terminal body and connects to a double-sided copper-clad ceramic substrate, with the angle between the stress buffer plate and the terminal body exceeding 90°. Compared to existing technologies, this invention employs an inclined stress buffer plate, allowing it to be positioned at an obtuse angle to the terminal body, avoiding the perpendicular arrangement of the stress buffer plate and the terminal body. Under three-dimensional composite stress, the overall stress distribution is more uniform, significantly reducing stress concentration and improving vibration fatigue resistance. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A simulation diagram illustrating the stress analysis of existing power module terminals;

[0030] Figure 2 A schematic diagram of the power module terminal provided in an embodiment of this utility model from a first-view perspective;

[0031] Figure 3 A schematic diagram of the power module terminals provided in an embodiment of this utility model from a second perspective;

[0032] Figure 4 A schematic diagram of the power module terminals provided in an embodiment of this utility model from a third-person perspective;

[0033] Figure 5 A simulation diagram of stress analysis of power module terminals provided for an embodiment of this utility model;

[0034] Figure 6 A circuit topology diagram of the first power module packaging structure provided in this embodiment of the present invention;

[0035] Figure 7 An overall structural diagram of the first power module packaging structure provided in this embodiment of the utility model;

[0036] Figure 8 An exploded view of the first power module packaging structure provided in this embodiment of the utility model;

[0037] Figure 9 for Figure 7 A schematic diagram of the power module packaging structure after removing the packaging module;

[0038] Figure 10 for Figure 9 A schematic diagram of the power module packaging structure after removing the power module terminals;

[0039] Figure 11 for Figure 10 A schematic diagram of the power module packaging structure after removing the bonding wires;

[0040] Figure 12 A circuit topology diagram of the second power module packaging structure provided in this embodiment of the present invention;

[0041] Figure 13 This is an overall structural diagram of the second power module packaging structure provided in this embodiment of the utility model;

[0042] Figure 14 This is an exploded structural diagram of the second power module packaging structure provided in this embodiment of the present utility model;

[0043] Figure 15 for Figure 14 A schematic diagram of the power module packaging structure after removing the packaging module;

[0044] Figure 16 for Figure 15 A schematic diagram of the power module packaging structure after removing the power module terminals;

[0045] Figure 17 for Figure 16 A schematic diagram of the power module packaging structure after removing the bonding wires;

[0046] Figure 18 Circuit topology diagram of the third power module packaging structure provided in this embodiment of the utility model;

[0047] Figure 19 A schematic diagram of the third power module packaging structure provided in this embodiment of the present invention after removing the packaging shell;

[0048] Figure 20 for Figure 19 A schematic diagram of the structure after removing the power module terminals.

[0049] Icons: 100 - Power module terminal; 10a - First power terminal; 10b - Second power terminal; 10c - Third power terminal; 110 - Terminal body; 111 - Terminal connection part; 113 - Terminal fixing part; 115 - Arc-shaped bend part; 117 - Stress relief hole; 130 - Stress buffer plate; 150 - Welding plate; 200 - Power module packaging structure; 210 - Heat dissipation substrate; 220 - Packaging shell; 230 - Double-sided copper-clad ceramic substrate; 231 - Source region; 2 32 - Drain region; 233 - Gate region; 234 - Gate resistor; 235 - Kelvin source region; 240 - Power chip; 241 - First conductive element; 242 - Second conductive element; 243 - Third conductive element; 244 - Fourth conductive element; 245 - Molybdenum sheet; 250a - First signal terminal; 250b - Second signal terminal; 250c - Third signal terminal; 250d - Fourth signal terminal; 260 - Schottky barrier diode; 270 - Negative temperature coefficient thermistor. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0054] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0055] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0056] See Figures 2 to 4 This utility model embodiment provides a power module terminal 100, which, through structural optimization design, makes the overall stress more uniform when subjected to three-dimensional composite stress. The stress concentration of the overall structure of the power terminal is significantly reduced when subjected to three-dimensional composite stress, and the vibration fatigue resistance is improved.

[0057] The power module terminal 100 provided in this embodiment of the present invention includes a terminal body 110 and a stress buffer plate 130 disposed at the bottom end of the terminal body 110. The top end of the terminal body 110 is configured to partially extend out of the encapsulation shell 220 and be connected to an external conductive component. The stress buffer plate 130 extends obliquely downward from the bottom end of the terminal body 110 and is configured to be connected to a double-sided copper-clad ceramic substrate 230. The included angle between the stress buffer plate 130 and the terminal body 110 is greater than 90°.

[0058] It should be noted that in this embodiment, the power module terminal 100 is applicable to the power module packaging structure 200, preferably a SiC power module packaging structure 200. A double-sided copper-clad ceramic substrate 230 is disposed within the packaging shell 220. The terminal body 110 and the stress buffer plate 130 can be accommodated within the packaging shell 220. The terminal body 110 and the stress buffer plate 130 are integrally formed, with the stress buffer plate 130 connected to the double-sided copper-clad ceramic substrate 230. The top end of the terminal body 110 extends out of the packaging shell 220 and connects to external conductive lines, thereby achieving internal and external electrical connection.

[0059] This embodiment employs an inclined stress buffer plate 130, allowing the stress buffer plate 130 and the terminal body 110 to be set at an obtuse angle, avoiding the perpendicular arrangement between the stress buffer plate 130 and the terminal body 110. Under the combined stress in three dimensions, the overall stress distribution is more uniform, the stress concentration of the power terminal structure under three-dimensional combined stress is significantly reduced, and the vibration fatigue resistance is improved.

[0060] Furthermore, a transition arc edge is formed between the stress buffer plate 130 and the terminal body 110, and the included angle between the stress buffer plate 130 and the terminal body 110 is between 120° and 170°, preferably 150°. Specifically, the stress buffer plate 130 and the terminal body 110 are integrally formed. In actual assembly, the part connecting the terminal body 110 and the stress buffer plate 130 extends in the vertical direction, so the included angle between the stress buffer plate 130 and the vertical plane can also be considered as 30°. In actual use, the stress buffer plate 130 and the terminal body 110 are subjected to external high-frequency stress, and the connection between the stress buffer plate 130 and the terminal body 110 is a stress concentration area. However, since the included angle between the stress buffer plate 130 and the vertical terminal body 110 is 150°, the stress can be effectively released, making the overall stress more uniform. Therefore, when the overall structure is subjected to three-dimensional composite stress, the stress concentration is significantly reduced, and the vibration fatigue resistance is improved.

[0061] In some embodiments, a welding plate 150 is further provided at the end of the stress buffer plate 130 away from the terminal body 110. A transition arc edge is formed between the welding plate 150 and the stress buffer plate 130, and the included angle formed between the welding plate 150 and the stress buffer plate 130 is greater than 0° and less than 90°. Further, the included angle formed between the welding plate 150 and the stress buffer plate 130 can be between 30° and 80°, and the welding plate 150 is configured to be welded to the double-sided copper-clad ceramic substrate 230. Specifically, the welding plate 150 is bonded to the double-sided copper-clad ceramic substrate 230, and the welding plate 150 can extend in the horizontal direction. Preferably, the included angle between the welding plate 150 and the stress buffer plate 130 is 60°. By setting the welding plate 150, the welding reliability between the stress buffer plate 130 and the double-sided copper-clad ceramic substrate 230 can be guaranteed. At the same time, the welding plate 150 can achieve stress dispersion, so that the stress buffer plate 130 and the double-sided copper-clad ceramic substrate 230 can also be buffered, further making the overall stress of the power terminal more uniform.

[0062] In some embodiments, the terminal body 110 includes a terminal connecting portion 111 and a terminal fixing portion 113. A stress buffer plate 130 is connected to the bottom end of the terminal connecting portion 111, and the terminal fixing portion 113 is connected to the top end of the terminal connecting portion 111 and is bent in the same way as the terminal connecting portion 111. Specifically, the terminal connecting portion 111 and the terminal fixing portion 113 are integrally formed, and the terminal connecting portion 111 can extend vertically, while the terminal fixing portion 113 can extend horizontally. Therefore, the terminal connecting portion 111 and the terminal fixing portion 113 can be bent at a 90° angle. The top end of the terminal connecting portion 111 can extend out of the encapsulation housing 220, while the terminal fixing portion 113 is located outside the encapsulation housing 220 and connected to the top end of the terminal connecting portion 111, enabling a fixed connection with an external conductive component. The external conductive component can be a wire coupled with a crimping screw, and its connection method can refer to existing terminal structures.

[0063] In some embodiments, the terminal fixing portion 113 and the welding plate 150 are parallel to each other, and the distance L1 between the terminal connecting portion 111 and the welding plate 150 is 1 / 5 to 2 / 3 of the distance L2 between the terminal fixing portion 113 and the welding plate 150. The terminal fixing portion 113 and the welding plate 150 are both parallel to each other in the horizontal direction, and L1 is preferably 1 / 3 of L2. This dimensional limitation effectively ensures the length of the stress buffer plate 130, thereby making the stress buffer plate 130 have a larger stress-bearing area and more uniform stress distribution.

[0064] In some embodiments, the connection between the terminal connecting portion 111 and the terminal fixing portion 113 is an arc-shaped bend 115, and a stress relief hole 117 is also provided on the arc-shaped bend 115. Specifically, the terminal fixing portion 113, the terminal connecting portion 111, and the stress buffer plate 130 are all integrally formed. By providing the stress relief hole 117 during manufacturing, it is possible to easily achieve a bending structure between the terminal fixing portion 113 and the terminal connecting portion 111.

[0065] It is worth noting that when conducting simulation tests, such as Figure 5 As shown, simulation results indicate that when the power module terminal 100 at a 60-degree angle is subjected to three-dimensional composite stress, the arc-shaped area connecting the vertical and horizontal planes remains a stress concentration area, but the overall stress is more uniform. The stress concentration of the power terminal's overall structure is significantly reduced when subjected to three-dimensional composite stress, and its vibration fatigue resistance is improved.

[0066] See Figures 6 to 11 This utility model embodiment also provides a power module packaging structure 200, which adopts the aforementioned power module terminal 100, improves fatigue resistance, greatly enhances service life, and through structural layout improvement, enables the power module terminal 100 to be compatible with different packaging structure schemes.

[0067] The power module packaging structure 200 provided in this embodiment includes a heat dissipation substrate 210, a packaging shell 220, a double-sided copper-clad ceramic substrate 230, multiple power chips 240, and multiple power module terminals 100. The packaging shell 220 is disposed on the heat dissipation substrate 210 and forms a packaging cavity. The double-sided copper-clad ceramic substrate 230 is disposed on the heat dissipation substrate 210. Multiple power chips 240 are mounted on the double-sided copper-clad ceramic substrate 230. Multiple power module terminals 100 are sequentially and spaced apart on the double-sided copper-clad ceramic substrate 230. Multiple stress buffer plates 130 are all accommodated in the packaging cavity and connected to the double-sided copper-clad ceramic substrate 230. The top ends of multiple terminal bodies 110 partially extend out of the packaging shell 220 and are configured to connect with external conductive components. The basic structure of the power module terminal 100 can be referred to the above content. The welding plate 150 of the power module terminal 100 is welded and fixed on the double-sided copper-clad ceramic substrate 230, and the terminal fixing part 113 of the double-sided copper-clad ceramic substrate 230 extends out of the packaging shell 220.

[0068] It should be noted that the power module package structure 200 here can be a single-tube module composed of multiple SiC MOSFETs connected in parallel.

[0069] In some embodiments, the circuit topology of the power module package structure 200 is as follows: Figure 6As shown, a first signal terminal 250a and a second signal terminal 250b are also provided on the double-sided copper-clad ceramic substrate 230. Multiple power chips 240 are connected in parallel, with the drains of each power chip 240 electrically connected to at least one power module terminal 100, the sources of each power chip 240 electrically connected to the remaining power module terminals 100 and the first signal terminal 250a, and the gates of each power chip 240 electrically connected to the second signal terminal 250b. The power chips 240 are SiC MOSFET chips, each with a source and gate on the front side and a drain on the back side. Multiple SiC MOSFET chips are connected in parallel to meet the current carrying capacity requirements, and reverse freewheeling is achieved through the body diode of the SiC MOSFET chip itself. Figure 6 The pin numbers in the circuit topology shown are... Figure 7 The terminal numbers on the enclosure 220 in the top view correspond to the terminal numbers.

[0070] In some embodiments, the double-sided copper-clad ceramic substrate 230 includes at least one direct-bonding copper substrate (DBC). Preferably, two different direct-bonding copper substrates can be used to implement the circuit, and the two direct-bonding copper substrates can be connected by bonding wires. The direct-bonding copper substrate refers to a copper-clad ceramic substrate, which uses ceramic as a substrate and has copper clad on its surface. The direct-bonding copper substrate has a source region 231, a drain region 232, and a gate region 233 that are electrically separated from each other. Both the source region 231 and the drain region 232 are connected to at least one power module terminal 100. Multiple power chips 240 are disposed with their drains facing down on the drain region 232, so that the drains of the multiple power chips 240 are electrically connected to the power module terminal 100 of the drain region 232. The sources of multiple power chips 240 are connected to the source region 231 via multiple first conductive elements 241, so that the sources of all power chips 240 are electrically connected to the power module terminals of the source region 231. The source region 231 is connected to the first signal terminal 250a via a second conductive element 242, so that the sources of all power chips 240 are electrically connected to the first signal terminal 250a. The gate region 233 is located between the source region 231 and the drain region 232. The gate region 233 is provided with multiple gate resistors 234, and the gates of the multiple power chips 240 are connected to the gate region 233 via the multiple gate resistors 234. The gate region 233 is connected to the second signal terminal 250b via a third conductive element 243, so that the gates of all power chips 240 are electrically connected to the second signal terminal 250b. Specifically, the gates of multiple power chips 240 are respectively led out through bonding wires and connected to a portion of the gate region 233 connected to one end of the gate resistor 234, while the other end of the gate resistor 234 is connected to another portion of the gate region 233, and finally connected to the second signal terminal 250b through the third conductive element 243.

[0071] Furthermore, in this embodiment, the multiple power module terminals 100 include a first power terminal 10a, a second power terminal 10b, and a third power terminal 10c. During the layout of the copper-clad substrate, the back sides of the multiple power chips 240 are attached to the drain region 232, and the first power terminal 10a is soldered to the drain region 232. Therefore, the first power terminal 10a can be correspondingly connected to the drain of the power chip 240 (i.e., the back side of the power chip 240). The second power terminal 10b and the third power terminal 10c are soldered to the source region 231, and the source region 231 is connected to the source of the multiple power chips 240 on the front side through multiple first conductive elements 241. A molybdenum sheet 245 can also be additionally designed on the front side of the power chip 240 to improve electrical connection characteristics, and the molybdenum sheet 245 can also buffer thermal stress. The source signal of the power chip 240 is directly led out from the power return to the first signal terminal 250a through the second conductive element 242. The gate of each power chip 240 is connected to one end of the gate resistor 234 soldered to the gate region 233 via a bonding wire. The other end of each gate resistor 234 is connected via a copper layer trace in the gate region 233 and connected to the second signal terminal 250b via a third conductive element 243.

[0072] It is worth noting that the first conductive element 241, the second conductive element 242, and the third conductive element 243 are all bonding wires or copper connecting bridges, preferably bonding wires. The process flow of the power module packaging structure 200 proposed in this utility model is as follows: First, the power chip 240 and the gate resistor 234 are respectively soldered to the drain region 232 and the gate region 233 of two copper-clad ceramic substrates through screen printing, surface mount technology and reflow soldering. Then, the gate, source and copper-clad ceramic substrates of the power chip 240 are interconnected through bonding. Next, the two copper-clad ceramic substrates are soldered to the heat dissipation substrate 210 through screen printing and reflow soldering, and the two copper-clad ceramic substrates are interconnected through bonding. Then, the first power terminal 10a, the second power terminal 10b, the third power terminal 10c, the first signal terminal 250a and the second signal terminal 250b are correspondingly soldered to the copper-clad ceramic substrates. Then, the packaging shell 220 and the heat dissipation substrate 210 are assembled using sealant and rivets. Then, potting compound is injected and cured. Finally, the part of the power terminal that extends beyond the shell is bent, that is, the terminal fixing part 113 is bent.

[0073] See Figures 12 to 17 In some embodiments, the circuit topology of the power module package structure 200 is as follows: Figure 12As shown, a plurality of power chips 240, a first signal terminal 250a, a second signal terminal 250b, and a plurality of Schottky barrier diodes 260 are disposed on a double-sided copper-clad ceramic substrate 230. The power chips 240 are connected in parallel, with their drains electrically connected to at least one power module terminal 100, their sources electrically connected to the remaining power module terminals 100 and the first signal terminal 250a, and their gates electrically connected to the second signal terminal 250b. The Schottky barrier diodes 260 can be SiC SBDs (Schottky Barrier Diodes). The cathodes of the Schottky barrier diodes 260 are electrically connected to the drains of the power chips 240, and their anodes are correspondingly connected to the sources of the power chips 240. Multiple SiC MOSFET chips are connected in parallel to meet current rating requirements, while multiple SiC SBD chips are connected in anti-parallel to enhance their reverse freewheeling capability. Figure 12 The pin numbers in the circuit topology shown are... Figure 13 The terminal numbers on the enclosure 220 in the top view correspond to the terminal numbers.

[0074] In some embodiments, the double-sided copper-clad ceramic substrate 230 includes a copper-clad substrate having electrically separated source region 231, drain region 232, gate region 233, and Kelvin source region 235. The gate region 233 and Kelvin source region 235 are disposed between the source region 231 and the drain region 232. Both the source region 231 and the drain region 232 are connected to at least one power module terminal 100. Multiple power chips 240 are disposed with their drains facing down on the drain region 232, so that the drains of the multiple power chips 240 are electrically connected to the power module terminal 100 of the drain region 232. Multiple Schottky barrier diodes 260 are disposed with their cathodes facing down on the drain region 232, so that the cathodes of the multiple Schottky barrier diodes 260 are electrically connected to the power module terminal 100 of the drain region 232. The sources of multiple power chips 240 and the anodes of multiple Schottky barrier diodes 260 are respectively connected to the source region 231 through multiple first conductive elements 241, so that the sources of multiple power chips 240 and the anodes of multiple Schottky barrier diodes 260 are electrically connected to the power module terminal 100 of the source region 231. The Kelvin sources of multiple power chips 240 are connected to the Kelvin source region 235, and the Kelvin source region 235 is connected to the first signal terminal 250a through a second conductive element 242, so that the Kelvin sources of multiple power chips 240 are electrically connected to the first signal terminal 250a. The gate region 233 is located between the source region 231 and the drain region 232. The gates of multiple power chips 240 are respectively connected to the gate region 233 through a third conductive element 243, and the gate region 233 is connected to the second signal terminal 250b through a fourth conductive element 244, so that the gates of multiple power chips 240 are all electrically connected to the second signal terminal 250b. Among them, the first conductive element 241, the second conductive element 242, the third conductive element 243 and the fourth conductive element 244 can all be bonding wires and copper connecting bridges. Preferably, the first conductive element 241 is a copper connecting bridge, and the second conductive element 242, the third conductive element 243 and the fourth conductive element 244 are all bonding wires. Compared with bonding wires, copper connecting bridges are beneficial to increasing current carrying capacity, reducing parasitic parameters and improving reliability.

[0075] Furthermore, in this embodiment, the multiple power module terminals 100 also include a first power terminal 10a, a second power terminal 10b, and a third power terminal 10c. During the layout of the copper-clad substrate, the back sides of the multiple power chips 240 and the back sides of the multiple Schottky barrier diodes 260 are attached to the drain region 232. The first power terminal 10a is soldered to the drain region 232, so the first power terminal 10a can be correspondingly connected to the drain of the power chip 240 (i.e., the back side of the power chip 240) and the cathode of the Schottky barrier diode 260 (i.e., the back side of the Schottky barrier diode 260). The second power terminal 10b and the third power terminal 10c are soldered to the source region 231, and the source region 231 is connected to the source on the front side of the multiple power chips 240 and the anode on the front side of the multiple Schottky barrier diodes 260 through multiple copper connecting bridges. The power chip 240 and the Schottky barrier diode 260 can also have an additional molybdenum sheet 245 designed on their front sides. While ensuring electrical connection performance, the molybdenum sheet 245 can also buffer thermal stress. The gate of each power chip 240 is connected to the gate region 233 via bonding wires, and the copper layer of the gate region 233 is connected to the second signal terminal 250b via bonding wires. Furthermore, the Kelvin source of the power chip 240 is connected to the copper-clad substrate via bonding wires and led out to the first signal terminal 250a via copper layer traces and bonding wires.

[0076] In some embodiments, a negative temperature coefficient thermistor 270, a third signal terminal 250c, and a fourth signal terminal 250d are also disposed on the double-sided copper-clad ceramic substrate 230. The two ends of the negative temperature coefficient thermistor 270 are electrically connected to the third signal terminal 250c and the fourth signal terminal 250d, respectively. Specifically, by adding the negative temperature coefficient thermistor 270 (NTC), the junction temperature detection function of the power module package structure 200 can be realized. In actual layout, the two ends of the NTC resistor are soldered to the copper-clad substrate, and connected to the areas where the third signal terminal 250c and the fourth signal terminal 250d are connected to the copper-clad substrate through copper layer traces.

[0077] It is worth noting that the process flow of the power module packaging structure 200 here is as follows: First, the interconnection between the power chip 240 and the copper-clad ceramic substrate, the Schottky barrier diode 260 and the copper-clad ceramic substrate, the molybdenum sheet 245 and the power chip 240, the copper connecting bridge and the molybdenum sheet 245 and the copper-clad ceramic substrate, and the NTC resistor and the copper-clad ceramic substrate are achieved through screen printing, surface mount technology (SMT), dispensing, and reflow soldering. Then, the gate, Kelvin source, and copper-clad ceramic substrate of the power chip 240 are interconnected through bonding. Next, the copper-clad ceramic substrate and the heat sink 210, as well as the power terminals and signal terminals and the copper-clad ceramic substrate, are interconnected through screen printing, dispensing, and reflow soldering. Then, the housing and the heat sink 210 are assembled using sealant and rivets. Then, potting compound is injected and cured. Finally, the portion of the power module terminals 100 extending beyond the housing is bent.

[0078] See Figures 18 to 20 In some embodiments, the circuit topology of the power module package structure 200 is as follows: Figure 18 As shown, a plurality of power chips 240, a first signal terminal 250a, and a second signal terminal 250b are disposed on a double-sided copper-clad ceramic substrate 230. The plurality of power chips 240 are arranged in parallel, and the drains of the plurality of power chips 240 are electrically connected to at least one of the power module terminals 100, the sources of the plurality of power chips 240 are electrically connected to the remaining power module terminals 100 and the first signal terminal 250a, and the gates of the plurality of power chips 240 are electrically connected to the second signal terminal 250b.

[0079] In some embodiments, the double-sided copper-clad ceramic substrate 230 includes at least one copper-clad substrate. Preferably, two different copper-clad substrates can be used to implement the circuit, and the two copper-clad substrates can be connected by bonding wires. The copper-clad substrate has a source region 231, a drain region 232, and a gate region 233 that are electrically separated from each other. Both the source region 231 and the drain region 232 are connected to at least one power module terminal 100. A plurality of power chips 240 are disposed with their drains facing down on the drain region 232, so that the drains of the plurality of power chips 240 are electrically connected to the power module terminal 100 of the drain region 232. The sources of the plurality of power chips 240 are respectively connected to the source region 231 through a plurality of first conductive elements 241, and the source region 231 is connected to the first signal terminal 250a through a second conductive element 242, so that the sources of the plurality of power chips 240 are electrically connected to the power module terminal 100 and the first signal terminal 250a of the source region 231. The gate region 233 is located between the source region 231 and the drain region 232. The gate region 233 is provided with a plurality of gate resistors 234. The gates of the plurality of power chips 240 are respectively connected to the gate region 233 through the plurality of gate resistors 234. The gate region 233 is connected to the second signal terminal 250b through the third conductive element 243, so that the gates of the plurality of power chips 240 are electrically connected to the second signal terminal 250b.

[0080] Furthermore, in this embodiment, the multiple power module terminals 100 include a first power terminal 10a, a second power terminal 10b, and a third power terminal 10c. During the layout of the copper-clad substrate, the back sides of the multiple power chips 240 are attached to the drain region 232, and the first power terminal 10a and the second power terminal 10b are soldered to the drain region 232. Therefore, the first power terminal 10a and the second power terminal 10b can be correspondingly connected to the drain of the power chip 240 (i.e., the back side of the power chip 240). The third power terminal 10c is soldered to the source region 231, and the source region 231 is connected to the source of the multiple power chips 240 on the front side through multiple bonding wires. The source signal of the power chip 240 is directly led out from the power return circuit to the first signal terminal 250a through the bonding wires. The gate of each power chip 240 is connected to one end of the gate resistor 234 soldered to the gate region 233 via a bonding wire. The other end of each gate resistor 234 is connected via a copper layer trace in the gate region 233 and connected to the second signal terminal 250b via a bonding wire.

[0081] In summary, the power module terminal 100 and power module packaging structure 200 provided in this embodiment of the present invention have a stress buffer plate 130 at the bottom end of the terminal body 110, while the top end is configured to partially extend out of the packaging shell 220 and connect to an external conductive component. The stress buffer plate 130 extends obliquely downward from the bottom end of the terminal body 110 and connects to the double-sided copper-clad ceramic substrate 230, and the angle formed between the stress buffer plate 130 and the terminal body 110 is greater than 90°. Compared with the prior art, the present invention uses an obliquely constructed stress buffer plate 130, which allows the stress buffer plate 130 and the terminal body 110 to be set at an obtuse angle, avoiding the perpendicular arrangement between the stress buffer plate 130 and the terminal body 110. Under the combined stress in three dimensions, the overall stress is more uniform, the stress concentration of the overall structure of the power terminal under the combined stress in three dimensions is significantly reduced, and the vibration fatigue resistance is improved. In addition, the power module terminal 100 is compatible with different power module packaging structures 200, and has good applicability.

[0082] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A power module terminal, characterized in that, The device includes a terminal body (110) and a stress buffer plate (130) disposed at the bottom end of the terminal body (110). The top end of the terminal body (110) is configured to partially extend out of the encapsulation shell (220) and connect to an external conductive element. The stress buffer plate (130) extends obliquely downward from the bottom end of the terminal body (110) and is configured to connect to a double-sided copper-clad ceramic substrate (230). The included angle between the stress buffer plate (130) and the terminal body (110) is greater than 90°.

2. The power module terminal according to claim 1, characterized in that, A transition arc edge is formed between the stress buffer plate (130) and the terminal body (110).

3. The power module terminal according to claim 1 or 2, characterized in that, A welding plate (150) is also provided at one end of the stress buffer plate (130) away from the terminal body (110). The angle between the welding plate (150) and the stress buffer plate (130) is greater than 0° and less than 90°, and the welding plate (150) is configured to be welded to the double-sided copper-clad ceramic substrate (230).

4. The power module terminal according to claim 3, characterized in that, A transition arc edge is formed between the welding plate (150) and the stress buffer plate (130).

5. The power module terminal according to claim 3, characterized in that, The terminal body (110) includes a terminal connecting part (111) and a terminal fixing part (113). The stress buffer plate (130) is connected to the bottom end of the terminal connecting part (111), and the terminal fixing part (113) is connected to the top end of the terminal connecting part (111) and is bent with the terminal connecting part (111).

6. The power module terminal according to claim 5, characterized in that, The terminal fixing part (113) is parallel to the welding plate (150), and the distance L1 between the terminal connecting part (111) and the welding plate (150) is 1 / 5 to 2 / 3 of the distance L2 between the terminal fixing part (113) and the welding plate (150).

7. The power module terminal according to claim 5, characterized in that, The terminal connecting part (111) has an arc-shaped bend (115) at its top end, and the terminal fixing part (113) is connected to the arc-shaped bend (115).

8. A power module packaging structure, characterized in that, The package includes a heat dissipation substrate (210), a package housing (220), a double-sided copper-clad ceramic substrate (230), a plurality of power chips (240), and a plurality of power module terminals as described in any one of claims 1-7. The package housing (220) is disposed on the heat dissipation substrate (210) and forms a package cavity. The double-sided copper-clad ceramic substrate (230) is disposed on the heat dissipation substrate (210). The plurality of power chips (240) are mounted on the double-sided copper-clad ceramic substrate (230). The plurality of power module terminals are sequentially spaced on the double-sided copper-clad ceramic substrate (230). The plurality of stress buffer plates (130) are all housed in the package cavity and connected to the double-sided copper-clad ceramic substrate (230). The top ends of the plurality of terminal bodies (110) partially extend out of the package housing (220) and are configured to be connected to external conductive components.

9. The power module packaging structure according to claim 8, characterized in that, The double-sided copper-clad ceramic substrate (230) is further provided with a first signal terminal (250a) and a second signal terminal (250b). A plurality of power chips (240) are arranged in parallel, and the drains of the plurality of power chips (240) are electrically connected to at least one of the power module terminals. The sources of the plurality of power chips (240) are electrically connected to the remaining power module terminals and the first signal terminal (250a). The gates of the plurality of power chips (240) are electrically connected to the second signal terminal (250b).

10. The power module packaging structure according to claim 9, characterized in that, The double-sided copper-clad ceramic substrate (230) includes at least one copper-clad substrate, which has a source region (231), a drain region (232) and a gate region (233) that are electrically separated from each other. The source region (231) and the drain region (232) are each connected to at least one of the power module terminals. Multiple power chips (240) are attached to the drain region (232) with their drains facing downwards, so that the drains of the multiple power chips (240) are electrically connected to the power module terminals of the drain region (232); The sources of the plurality of power chips (240) are respectively connected to the source region (231) through a plurality of first conductive elements (241), so that the sources of the plurality of power chips (240) are electrically connected to the power module terminals of the source region (231), and the source region (231) is connected to the first signal terminal (250a) through a second conductive element (242), so that the sources of the plurality of power chips (240) are electrically connected to the first signal terminal (250a); The gate region (233) is located between the source region (231) and the drain region (232). The gate region (233) is provided with a plurality of gate resistors (234). The gates of the plurality of power chips (240) are respectively connected to the gate region (233) through the plurality of gate resistors (234). The gate region (233) is connected to the second signal terminal (250b) through a third conductive element (243) so that the gates of the plurality of power chips (240) are electrically connected to the second signal terminal (250b).

11. The power module packaging structure according to claim 9, characterized in that, The double-sided copper-clad ceramic substrate (230) is also provided with a plurality of Schottky barrier diodes (260), the cathodes of the plurality of Schottky barrier diodes (260) are electrically connected to the drains of the plurality of power chips (240), and the anodes of the plurality of Schottky barrier diodes (260) are respectively connected to the sources of the plurality of power chips (240).

12. The power module packaging structure according to claim 11, characterized in that, The double-sided copper-clad ceramic substrate (230) includes a copper-clad substrate, on which there are electrically separated source region (231), drain region (232), gate region (233) and Kelvin source region (235), and the source region (231) and the drain region (232) are each connected to at least one of the power module terminals. Multiple power chips (240) are attached to the drain region (232) with their drains facing downwards, so that the drains of the multiple power chips (240) are electrically connected to the power module terminals of the drain region (232); Multiple Schottky barrier diodes (260) are mounted with their cathodes facing downwards in the drain region (232) so that the cathodes of the multiple Schottky barrier diodes (260) are electrically connected to the power module terminals in the drain region (232). The sources of the multiple power chips (240) and the anodes of the multiple Schottky barrier diodes (260) are respectively connected to the source region (231) through multiple first conductive elements (241), so that the sources of the multiple power chips (240) and the anodes of the multiple Schottky barrier diodes (260) are electrically connected to the power module terminals of the source region (231), and the Kelvin sources of the multiple power chips (240) are connected to the Kelvin source region (235), and the Kelvin source region (235) is connected to the first signal terminal (250a) through a second conductive element (242), so that the Kelvin sources of the multiple power chips (240) and the first signal terminal (250a) are electrically connected; The gate region (233) is located between the source region (231) and the drain region (232). The gates of the plurality of power chips (240) are respectively connected to the gate region (233) through a third conductive element (243). The gate region (233) is connected to the second signal terminal (250b) through a fourth conductive element (244), so that the gates of the plurality of power chips (240) are electrically connected to the second signal terminal (250b).

13. The power module packaging structure according to claim 11, characterized in that, The double-sided copper-clad ceramic substrate (230) is also provided with a negative temperature coefficient thermistor (270), a third signal terminal (250c) and a fourth signal terminal (250d), and the two ends of the negative temperature coefficient thermistor (270) are electrically connected to the third signal terminal (250c) and the fourth signal terminal (250d) respectively.

Images