Packaging structure of plastic package power module

Abstract

The utility model discloses a kind of packaging structures of plastic package power module, including heat dissipation bottom plate, insulating substrate, chip, signal control component and for covering insulating substrate, chip and base plastic package body, welding surface is equipped on heat dissipation bottom plate, one side of insulating substrate is welded with welding surface and another side is equipped with conductive pattern layer, signal control component includes base and pin, chip and base are equipped in conductive pattern layer, pin one end is connected with base and another end penetrates plastic package body.Signal control component is directly led out plastic package body, without considering that power module internal conductive loop is connected by long distance cross-island bonding, the overall size of module can be obviously reduced, reduce the parasitic parameter in module. Base is arranged in plastic package body inside with interval, it is favorable to improve the bonding force of pin terminal and base.In the stage of using plastic package material to package each component, base is directly packaged in plastic package body inside, increase the migration distance of moisture and salt fog, the reliability of plastic package power module can be effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor power module packaging technology, and in particular to a packaging structure for a plastic-encapsulated power module. Background Technology

[0002] With the rapid development of new energy vehicles, electric drive technology is also advancing rapidly, and the main drive system is gradually developing towards high power density, small size, low weight, high integration, and modularity.

[0003] As a crucial component of new energy vehicles, the electric drive system's power module is a core component, responsible for converting the high-voltage direct current supplied by the battery pack into three-phase alternating current that can directly drive the motor. It needs to possess high efficiency and high reliability to meet the requirements of current main drive systems for high efficiency, high power density, and high reliability.

[0004] A power module typically consists of multiple components, including a heat sink for heat dissipation, terminals for connecting the battery pack and motor cables, signal pins for connecting drive signals, and epoxy resin or silicone gel for coating. Inside the module are multiple Insulated Gate Bipolar Transistors (IGBTs), Fast Recovery Diodes (FRDs) or Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), and a copper layer forming the internal conductive circuit. These components enable precise control of the motor through external circuitry such as driver boards and control boards.

[0005] To improve the power density of power modules, the size of the power modules is usually reduced. At the same time, considering the layout design of power modules, the pins are led out from the perimeter of the plastic package. This means that a large creepage distance and electrical clearance need to be maintained between modules to meet safety specifications.

[0006] Some existing technologies involve arranging pins in the middle of the module, but this approach reduces the module's airtightness and salt spray barrier effect by using sleeves or other pre-reserved space to place the pins, further affecting the module's lifespan. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a packaging structure for a plastic-encapsulated power module that is conducive to reducing overall size, reducing internal parasitic parameters, and improving reliability.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A plastic-encapsulated power module packaging structure includes a heat sink, an insulating substrate, a chip, a signal control component, and a plastic encapsulation body. The heat sink has a soldering surface. One side of the insulating substrate is soldered to the soldering surface, and the other side has a conductive pattern layer. Insulating trenches are provided between the conductive pattern layers. The signal control component includes a base and a pin. The chip and the base are disposed on the conductive pattern layer. The plastic encapsulation body is used to cover the insulating substrate, the chip, and the base. One end of the pin is connected to the base, and the other end passes through the plastic encapsulation body.

[0009] As a further improvement to the above technical solution: the conductive pattern layer is provided with power terminals, one end of which penetrates through the encapsulation.

[0010] As a further improvement to the above technical solution: the conductive pattern layer is further provided with a thermistor for detecting temperature, and the thermistor is disposed in the encapsulation body.

[0011] As a further improvement to the above technical solution: different chips are electrically connected to each other and to the conductive pattern layer through clips and / or bonding wires, wherein the clips and / or the bonding wires are disposed within the plastic encapsulation.

[0012] As a further improvement to the above technical solution: an annular barrier is provided around the welding surface.

[0013] As a further improvement to the above technical solution: a heat-conducting layer is provided between the insulating substrate and the welding surface, and the heat dissipation base plate is provided with a pin fin structure for heat dissipation. The pin fin structure is arranged opposite to the welding surface on both sides of the heat dissipation base plate.

[0014] As a further improvement to the above technical solution: one end of the pin is inserted into the base.

[0015] As a further improvement to the above technical solution: the encapsulation structure of the plastic-encapsulated power module also includes a plastic-encapsulating mold for forming the plastic-encapsulated body. The plastic-encapsulating mold includes a fixed upper mold, a movable lower mold, and a pressing mechanism disposed on the lower mold. The pressing mechanism includes a pressing rod, an elastic element, and a cylindrical pressing member for docking with the base. One end of the pressing rod is provided with a limiting part, and the other end is provided with a spiral line extending into the pressing member. One end of the elastic element abuts against the limiting part, and the other end abuts against the pressing member. An elastic sealing body is provided inside the pressing member.

[0016] As a further improvement to the above technical solution: the pin and the base are an integral structure.

[0017] As a further improvement to the above technical solution: the encapsulation structure of the plastic-encapsulated power module also includes a plastic-encapsulating mold for forming the plastic-encapsulated body. The plastic-encapsulating mold includes a fixed upper mold, a movable lower mold, and a pressing mechanism disposed on the lower mold. The pressing mechanism includes a pressing rod, an elastic element, and a cylindrical pressing member for docking with the base. One end of the pressing rod is provided with a limiting part, and the other end is provided with a spiral line that extends into the pressing member. One end of the elastic element abuts against the limiting part, and the other end abuts against the pressing member.

[0018] Compared with the prior art, the advantages of this utility model are: The packaging structure of the plastic-encapsulated power module disclosed in this utility model directly leads the signal control components out of the plastic package. During power module design, there is no need to consider connecting the internal conductive circuits of the power module via long-distance island bonding, which can significantly reduce the overall size of the module and effectively reduce internal parasitic parameters. The bases of the signal control components are spaced apart inside the plastic package, which can reduce uneven stress distribution within the module. By directly encapsulating the bases inside the plastic package during the encapsulation process, the migration distance of moisture and salt spray is increased, effectively improving the reliability of the plastic-encapsulated power module. Furthermore, the embedded bases within the plastic package enhance the bonding strength between the pin terminals and the bases.

[0019] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] Figure 1 This is a structural schematic diagram of Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the heat dissipation base plate in Embodiment 1 of this utility model.

[0021] Figure 3 This is a schematic diagram of the structure of the insulating substrate in Embodiment 1 of this utility model.

[0022] Figure 4 This is a schematic diagram of the signal control component in Embodiment 1 of this utility model.

[0023] Figure 5 This is a schematic diagram of the plastic sealing mold in Embodiment 1 of this utility model.

[0024] Figure 6 This is a schematic diagram of the crimping mechanism in Embodiment 1 of this utility model.

[0025] Figure 7 This is a schematic diagram of the connection between the crimping component and the base in one embodiment of this utility model.

[0026] Figure 8This is a structural schematic diagram of Embodiment 2 of this utility model.

[0027] Figure 9 This is a schematic diagram of the connection between the crimping component and the base in Embodiment 2 of this utility model.

[0028] The labels in the diagram represent: 1. Heat dissipation base plate; 11. Welding surface; 12. Annular enclosure; 13. Pin fin structure; 2. Insulating substrate; 21. Conductive pattern layer; 22. Thermally conductive layer; 3. Chip; 4. Clip; 5. Bonding wire; 6. Signal control component; 61. Base; 62. Pin; 7. Power terminal; 8. Thermistor; 9. Molded body; 101. Upper mold; 102. Lower mold; 103. Crimping mechanism; 1031. Elastic element; 1032. Crimping rod; 1033. Spiral; 1034. Crimping component; 1035. Elastic sealing body. Detailed Implementation

[0029] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. 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. Therefore, they should not be construed as limitations on this utility model.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In this utility model, unless otherwise explicitly specified and limited, the terms "assembly," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] To more clearly illustrate the technical principles of this utility model, several terms and concepts involved in this utility model will be explained.

[0034] Signal control components: also known as signal pins, in the integrated circuit industry, usually refer to the wiring that leads out from the internal circuit to connect with the external circuit. All the pins become the external interface of this chip.

[0035] Conductive pattern layer: Copper cladding is often used for conductivity, also known as copper cladding layer. It usually refers to a conductive circuit that is formed on the surface of an insulating material through processes such as deposition and sintering. In order to further achieve the characteristics required for electrical connection, the conductive copper layer usually has multiple insulating trenches to form different conductive circuits.

[0036] Clip: usually abbreviated as clip, it is mostly made of copper. In the power semiconductor industry, it is a copper strip with a certain shape design used to achieve electrical connection in order to further improve the output current capacity.

[0037] Parasitic parameters: These typically include technical terms such as parasitic resistance, parasitic capacitance, and parasitic inductance. In integrated circuits, under high-frequency switching conditions, the characteristic parameters of various components in the converter affect each other, thus causing a series of circuit operating mode changes. This results in a decrease in the switching speed of different components in the converter and a corresponding change in frequency, which in turn generates more energy loss. This loss is called parasitic loss.

[0038] Base: Usually called a holder, it is mostly made of copper and is a structure designed to bring out the internal circuitry of the module. It usually has through holes inside to facilitate the insertion of signal terminal pins, so as to realize the connection function between the internal electrical structure of the module and the external circuitry.

[0039] Crimping mechanism: commonly known as return pin, it is a mechanism designed on the molding die to control the deformation of the copper-clad insulating substrate during the molding process.

[0040] Example 1 like Figure 1 and Figure 2 As shown, the heat dissipation base plate 1 involved in this utility model has an annular barrier 12 that is higher than the welding surface 11 around its welding surface 11, which is used to control the overflow of solder during welding; the other side of the heat dissipation base plate 1 is provided with a needle wing structure 13, that is, the needle wing structure 13 is arranged opposite to the welding surface 11.

[0041] The needle-fin structure 13 is elliptical in shape, but it can also be rhomboid, circular, teardrop-shaped, or other shapes. Preferably, the needle-fin structure 13 can be used for direct water cooling to further improve the heat dissipation capacity of the heat dissipation base plate 1.

[0042] like Figure 3As shown, the insulating substrate 2 involved in this utility model is a copper-clad ceramic substrate. The copper-clad ceramic substrate contains a plurality of conductive pattern layers 21, and each independent conductive pattern layer 21 is connected to the insulating substrate 2 by means of soldering. The independent conductive pattern layers 21 can be arranged and sized according to different circuit topology designs to meet the requirements of different topology schemes.

[0043] Insulating ceramic substrates can be classified into silicon nitride ceramics, aluminum nitride ceramics, alumina ceramics, zirconium oxide ceramics, etc., according to the differences in raw material composition. The appropriate type can be selected based on the differences in product characteristics.

[0044] The other side of the insulating ceramic substrate is provided with a heat-conducting layer 22, which facilitates the transfer of heat to the welding surface 11, and finally heat dissipation is achieved through the aforementioned needle-fin structure 13 that can be used for direct water cooling.

[0045] Several chips 3: The drain / collector of chip 3 is connected to the conductive pattern layer 21 of the insulating ceramic substrate by solder. The source / emitter of chip 3 is electrically connected between different chips 3 and between chip 3 and conductive pattern layer 21 of the insulating ceramic substrate by copper clips 4 and bonding wires 5.

[0046] Several copper clips 4: used to achieve electrical connections between chips 3 and between chips 3 and the conductive pattern layer 21 of the insulating ceramic substrate.

[0047] Several bonding lines 5: used to realize the electrical connection between chip 3 and conductive pattern layer 21 of insulating ceramic substrate.

[0048] Several power terminals 7: One end of the power terminal 7 is soldered onto the conductive pattern layer 21 of the ceramic substrate by soldering / ultrasonic welding, and the other end is connected to the external current busbar by laser welding through the plastic encapsulation 9.

[0049] Thermistor 8: Thermistor 8 can be soldered / sintered on the conductive pattern layer 21 for monitoring the internal temperature of the module.

[0050] like Figure 4 As shown, the signal control component 6 involved in this utility model includes two parts: a base 61 and a pin 62. The copper-clad ceramic substrate is connected to an external PCB board through the pin 62, thereby realizing the switching function of the control chip 3. The base 61 is preferably made of copper. The copper ring base can be a "T" shaped structure or an "I" shaped structure. The electrical connection between the base 61 and the conductive pattern layer 21 on the copper-clad ceramic substrate is achieved by brazing, sintering or ultrasonic welding processes.

[0051] The pin 62 can be in the shape of a round pin, a straight pin, a fisheye pin, an S-pin, etc. Before injection molding, the base 61 and the pin 62 are separate structures. After injection molding to form the encapsulated body 9, the elastic sealing body 1035 is removed. The pin 62 can be inserted into the pin hole of the copper ring base through a plugging process to achieve electrical connection.

[0052] like Figure 5 As shown, the molding die involved in this utility model includes an upper mold 101, a lower mold 102, and a pressing mechanism 103; wherein the upper mold 101 of the molding die is a fixed mold that remains stationary during the molding process, and the lower mold 102 is a moving mold that moves up and down during the molding process to achieve the closing and opening of the molding die.

[0053] like Figure 6 As shown, the precision pressing mechanism 103 involved in this utility model is designed in the lower mold 101. During the molding process, as the lower mold 102 gradually moves upward, the pressing component 1034 in the pressing mechanism 103 gradually moves closer to the upper surface of the base 61. As the clamping force applied to the pressing rod 1032 gradually increases, the limiting part on the pressing rod 1032 (such as a flange or nut arranged in the circumferential direction) pushes the pressing component 1034 forward through the elastic component 1031 (such as a helical spring or elastic sleeve). During the pushing process, under the action of the spiral line 1033 on the pressing rod 1032, the pressing component 1034 can be spirally advanced, thereby realizing the precision connection between the pressing component 1034 and the base 61. This crimping mechanism 103 enables precise connection with the contact surfaces of copper ring bases of different heights, and can effectively improve the problem of excess adhesive on the module surface during the molding process. It can also reduce the deformation of the copper ring base caused by excessive pressure between the crimping mechanism 103 and the copper ring base, thus reducing the impact on the product's process feasibility.

[0054] like Figure 7 As shown, at the connection between the precision pressing mechanism and the copper ring base involved in this utility model, the pressing component 1034 has a cavity inside, which can accommodate a high-temperature resistant elastic sealing body 1035, providing good airtightness and salt spray barrier effects. This high-temperature resistant elastic sealing body 1035 is a consumable and needs to be replaced periodically.

[0055] Example 2 like Figure 8 and Figure 9 As shown, another embodiment of the encapsulation structure of the plastic-encapsulated power module of this utility model replaces the fisheye pin 62 with a straight pin, uses an integrated pin process for plastic encapsulation, and removes the high-temperature resistant elastic sealing body in the precision crimping mechanism to achieve an integrated plastic encapsulation process.

[0056] In this embodiment, before the power module components are encapsulated, the combination of the base 61 and the pin 62 is already achieved, or an integrated signal pin is used. During the encapsulation process, the high-temperature resistant elastic sealing body 1035 in the crimping part 1034 that contacts the copper ring base of the precision crimping mechanism needs to be removed in advance to achieve the encapsulation process with integrated pin.

[0057] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the present invention, or modify it into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, should fall within the protection scope of the present invention.

Claims

1. A packaging structure for a plastic-encapsulated power module, characterized in that: The device includes a heat dissipation base plate (1), an insulating substrate (2), a chip (3), a signal control component (6), and a molding compound (9). The heat dissipation base plate (1) has a welding surface (11). One side of the insulating substrate (2) is welded to the welding surface (11), and the other side has a conductive pattern layer (21). Insulating grooves are provided between the conductive pattern layers (21). The signal control component (6) includes a base (61) and a pin (62). The chip (3) and the base (61) are disposed on the conductive pattern layer (21). The molding compound (9) is used to cover the insulating substrate (2), the chip (3), and the base (61). One end of the pin (62) is connected to the base (61), and the other end passes through the molding compound (9).

2. The packaging structure of the plastic-encapsulated power module according to claim 1, characterized in that: The conductive pattern layer (21) is provided with a power terminal (7), one end of which penetrates the encapsulation (9).

3. The packaging structure of the plastic-encapsulated power module according to claim 1, characterized in that: The conductive pattern layer (21) is also provided with a thermistor (8) for detecting temperature, and the thermistor (8) is disposed inside the encapsulation (9).

4. The packaging structure of the plastic-encapsulated power module according to claim 1, characterized in that: Electrical connections are made between different chips (3) and between the chips (3) and the conductive pattern layer (21) via clips (4) and / or bonding wires (5), wherein the clips (4) and / or the bonding wires (5) are disposed within the encapsulation (9).

5. The packaging structure of the plastic-encapsulated power module according to claim 1, characterized in that: The welding surface (11) is surrounded by an annular enclosure (12).

6. The packaging structure of the plastic-encapsulated power module according to claim 1, characterized in that: A heat-conducting layer (22) is provided between the insulating substrate (2) and the welding surface (11). The heat dissipation base plate (1) is provided with a needle-wing structure (13) for heat dissipation. The needle-wing structure (13) and the welding surface (11) are arranged opposite to each other on both sides of the heat dissipation base plate (1).

7. The packaging structure of the plastic-encapsulated power module according to any one of claims 1 to 6, characterized in that: One end of the pin (62) is inserted into the base (61).

8. The packaging structure of the plastic-encapsulated power module according to claim 7, characterized in that: It also includes a molding die for forming the molding body (9), the molding die including a fixed upper die (101), a movable lower die (102) and a pressing mechanism (103) provided on the lower die (102), the pressing mechanism (103) including a pressing rod (1032), an elastic element (1031) and a cylindrical pressing member (1034) for docking with the base (61), one end of the pressing rod (1032) is provided with a limiting part, the other end is provided with a spiral (1033) and extends into the pressing member (1034), one end of the elastic element (1031) abuts against the limiting part, the other end abuts against the pressing member (1034), and the pressing member (1034) is provided with an elastic sealing body (1035).

9. The packaging structure of the plastic-encapsulated power module according to any one of claims 1 to 6, characterized in that: The pin (62) and the base (61) are an integral structure.

10. The packaging structure of the plastic-encapsulated power module according to claim 9, characterized in that: It also includes a molding die for forming the molding body (9), the molding die including a fixed upper die (101), a movable lower die (102) and a pressing mechanism (103) provided on the lower die (102), the pressing mechanism (103) including a pressing rod (1032), an elastic element (1031) and a cylindrical pressing member (1034) for docking with the base (61), one end of the pressing rod (1032) is provided with a limiting part, the other end is provided with a spiral (1033) and extends into the pressing member (1034), one end of the elastic element (1031) abuts against the limiting part, and the other end abuts against the pressing member (1034).

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