Packaging mold, power module and power conversion device
By innovating the design of the encapsulation mold and using a combination of a second mold and flexible filler, the problem of long production cycles caused by the cover plate was solved, resulting in a faster molding process and reduced costs.
Patent Information
- Application Number
- CN202423303029.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing power modules with top-mounted pins require a cover plate to block the flow of molding compound during the molding process, resulting in a long cover plate manufacturing cycle and affecting the development cycle of the power module.
The encapsulation mold design includes a first mold, a second mold, and a third mold. The second mold has a clearance hole on the first mold and cooperates with the flexible filler to avoid the use of a cover plate. The flexible filler fills the gap between the ejector pin and the clearance hole under the action of the third mold, ensuring that the molding compound does not overflow.
It shortens the production cycle of the items to be sealed, reduces costs, and improves the adaptability and production efficiency of the packaging mold.
Smart Images
Figure CN223872765U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor packaging technology, and in particular to a packaging mold, a power module, and a power conversion device. Background Technology
[0002] Power modules play a crucial role in the field of power electronics, serving as key components for functions such as power conversion, power amplification, power control, and protection. Top-mounted pins are a common structure in power modules, facilitating quick and easy crimping or soldering. In top-mounted pin power modules, the pin tops protrude above the module surface. To prevent interference between the upper cavity and the pins during mold closing, clearance holes are cut into the upper cavity at the corresponding pin positions. During mold closing, the portion of the pin above the module surface enters these clearance holes. Currently, top-mounted pin power modules require a cover plate to block the flow of molding compound during encapsulation. The cover plate and the injection-molded power module ultimately form a complete module. The cover plate requires injection molding, resulting in a long production cycle, which contributes to the long development cycle of power modules. Utility Model Content
[0003] This application provides a packaging mold, a power module, and a power conversion device. The design of the packaging mold can effectively shorten the production cycle of the object to be molded.
[0004] In a first aspect, embodiments of this application provide a packaging mold, comprising a first mold, a second mold, and a third mold, which are stacked sequentially. The first mold and the second mold cover together to form a receiving cavity for placing an object to be molded. The projected area of the second mold on the first mold is larger than the projected area of the object to be molded on the first mold. The second mold has a clearance hole communicating with the receiving cavity, penetrating both opposite sides of the second mold, for the ejector pin of the object to be molded to pass through. A flexible filler is provided between the second mold and the third mold. At least a portion of the flexible filler is used to fill the gap between the ejector pin and the sidewall of the clearance hole.
[0005] Currently, during the molding process of power modules, a cover plate is needed to block the flow of molding compound, and the clearance holes in the cover plate require sealing to prevent excess compound from leaking out at the ejector pins. Therefore, the cover plate typically consists of a substrate and a silicone pad. The silicone pad adhered to the substrate ensures an interference fit between the ejector pins and the silicone pad, thus preventing molding compound from leaking out from the gap between the ejector pins and the cover plate. Since both the substrate and the silicone pad are injection molded, the overall manufacturing cycle of the cover plate is long.
[0006] In this application, the second mold serves to position the ejector pins of the object to be molded (such as a molded power module with pins protruding from the top) and to place the flexible filler. The projected area of the second mold on the first mold is larger than the projected area of the object to be molded on the first mold. After the second and first molds are closed, the entire portion of the object to be molded, except for the ejector pins, can be contained within the receiving cavity. When molding compound is injected into the receiving cavity, it ensures that the molding compound can cover the edges of the object to be molded. Without a cover plate, the flexible filler can fill the gap between the ejector pin and the sidewall of the clearance hole under the force applied by the third mold, allowing the flexible filler to tightly wrap around the ejector pin and prevent the molding compound from flowing out from the gap, ensuring no excess glue around the ejector pin. Furthermore, both the second mold and the flexible filler are reusable or replaceable. The flexible filler does not require pre-forming, effectively shortening the manufacturing cycle of the object to be molded and reducing costs.
[0007] In conjunction with the first aspect, in one possible implementation, the dimension of the flexible filler on the side of the second mold opposite to the first mold along the stacking direction of the first mold and the second mold is greater than the dimension of the ejector pin on the side of the second mold opposite to the first mold along the stacking direction of the first mold and the second mold.
[0008] With this configuration, when the third mold applies a force to the flexible filler towards the first mold, the third mold will not squeeze the ejector pins that extend beyond the second surface. Furthermore, the flexible filler is larger in size along the stacking direction of the first and second molds, ensuring that it fills the gap between the ejector pins and the sidewalls of the clearance hole more quickly under the force applied by the third mold, thus shortening the production cycle of the product to be molded.
[0009] In conjunction with the first aspect, in one possible implementation, the encapsulation mold further includes a limiting member disposed around and limiting the flexible filler. The limiting member is located on the surface edge of the second mold opposite to the first mold, and / or, the limiting member is located on the surface edge of the third mold facing the second mold.
[0010] For example, a limiting member is located at the circumferential edge of the second mold surface away from the first mold. Another example is that a limiting member is located at the circumferential edge of the third mold surface facing the second mold. Yet another example is that a limiting member is located at the circumferential edge of the second mold surface away from the first mold, and simultaneously at the circumferential edge of the third mold surface facing the second mold; that is, both the second and third molds have limiting members. The limiting member restricts the flexible filler placed on the second mold, preventing the flexible filler from being squeezed beyond the edge of the second mold when the third mold applies a force towards the first mold, thus ensuring that the flexible filler can fully fill the gap between the ejector pin and the sidewall of the clearance hole.
[0011] In conjunction with the first aspect, in one possible implementation, the orthogonal projection of the flexible filler covers the clearance hole along the stacking direction of the first mold and the second mold.
[0012] The flexible filler covers all the clearance holes opened on the second mold. With this configuration, when the third mold applies a force toward the first mold to the flexible filler, the flexible filler can fill all the clearance holes, which can effectively prevent the molding compound from entering the clearance holes and causing glue overflow.
[0013] In conjunction with the first aspect, in one possible implementation, the orthographic projection of the third mold covers the orthographic projection of the flexible filler along the stacking direction of the first and second molds.
[0014] With this configuration, the third mold can apply force to the entire surface of the flexible filler, ensuring that the flexible filler can fully fill all the clearance holes and preventing glue overflow at the clearance holes.
[0015] In conjunction with the first aspect, in one possible implementation, the clearance hole includes a first hole segment and a second hole segment, the first hole segment and the second hole segment are arranged along the stacking direction of the first mold and the second mold, the first hole segment is closer to the first mold than the second hole segment along the stacking direction of the first mold and the second mold, and the diameter of the first hole segment is larger than the diameter of the second hole segment.
[0016] The ejector pins of the object to be plastic-sealed are sequentially inserted through the first hole section and the second hole section and extend to the side of the second mold opposite to the first mold. The first hole section with a larger diameter can play a guiding role, making it easier for the ejector pins of the object to be plastic-sealed to be inserted and effectively reducing assembly accuracy.
[0017] In conjunction with the first aspect, in one possible implementation, the number of second molds is at least two, each second mold is provided with multiple clearance holes, and the arrangement of the multiple clearance holes of each second mold is different.
[0018] That is, the number of clearance holes on the second mold is equal to the number of ejector pins of the same series of products to be molded. Thus, when molding products adapted to this second mold, the multiple ejector pins correspond one-to-one with the multiple clearance holes, preventing molded material from overflowing from too many clearance holes not pierced by ejector pins during injection molding. When molding other series of products, a second mold with a corresponding number of ejector pins can be used. By designing second molds for the ejector pin positions of different series of products, and adapting different customized second molds to a series of products with different ejector pin positions, the appropriate second mold can be used when molding different products, eliminating the need to replace the entire encapsulation mold. This also reduces the need for repeated development of the first and third molds, thus helping to lower costs.
[0019] In conjunction with the first aspect, in one possible implementation, the number of clearance holes is multiple, and the number of clearance holes is greater than the number of ejector pins on the object to be laminated. The multiple clearance holes are adapted to the multiple ejector pins of at least two objects to be laminated.
[0020] Multiple clearance holes are arranged at intervals, for example, in a matrix arrangement. This matrix arrangement allows for different combinations of clearance holes, accommodating materials with varying ejector pin positions. This reduces the frequency of second mold changes, improves the adaptability of the encapsulation mold, shortens the mold manufacturing cycle, and lowers the mold production cost.
[0021] In conjunction with the first aspect, in one possible implementation, the flexible filler includes rubber or silicone.
[0022] Secondly, embodiments of this application provide a power module manufactured using the packaging mold provided in the first aspect. The power module includes a substrate, a chip, ejector pins, and a molding compound. Both the chip and the ejector pins are electrically connected to the substrate. The extension direction of the ejector pins is parallel to the stacking direction of the substrate and the chip. The molding compound encapsulates the chip and part of the ejector pins.
[0023] Thirdly, embodiments of this application provide a power conversion device, which includes a circuit board and a power module as provided in the second aspect, the power module being connected to the circuit board. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.
[0025] Figure 1 A network diagram of a photovoltaic and energy storage system in a large-scale ground power station or industrial and commercial application scenario provided in an embodiment of this application;
[0026] Figure 2 This is a schematic diagram of a power conversion device provided in an embodiment of this application;
[0027] Figure 3 This is a schematic diagram of the structure of a packaging mold provided in one embodiment of this application;
[0028] Figure 4 A top view of a second mold provided in an embodiment of this application;
[0029] Figure 5 A top view of another second mold provided in an embodiment of this application;
[0030] Figure 6 This is a schematic diagram of the structure of the first mold and the second mold before they are closed, according to an embodiment of this application.
[0031] Figure 7 This is a schematic diagram of the structure of the packaging mold after mold closing, according to an embodiment of this application;
[0032] Figure 8 This is a schematic diagram of the structure of a packaging mold provided in one embodiment of this application;
[0033] Figure 9 This is a schematic diagram of another packaging mold provided in an embodiment of this application;
[0034] Figure 10 A schematic flowchart illustrating a method for fabricating a power module according to an embodiment of this application;
[0035] Figure 11 This is a schematic diagram of a power module encapsulated by a packaging mold according to an embodiment of this application.
[0036] Explanation of reference numerals in the attached figures:
[0037] 10-Power Module;
[0038] 11-Substrate; 12-Chip; 13-Ejector pin; 14-Molding layer;
[0039] 20 - Circuit board;
[0040] 30 - Packaging mold;
[0041] 31-First mold; 32-Second mold; 33-Third mold; 34-Receiving cavity; 35-Flexible filler; 36-Limiting component;
[0042] 321 - Clearance hole; 322 - First surface; 323 - Second surface; 331 - Fixing plate; 332 - Protrusion;
[0043] 3211 - First hole section; 3212 - Second hole section;
[0044] 100-Power conversion device;
[0045] 101-Photovoltaic inverter; 102-Energy storage converter;
[0046] 200 - Photovoltaic modules;
[0047] 300-Prefabricated Substation;
[0048] 400-Boosting Station;
[0049] 500-Power Grid;
[0050] 600-Energy Storage System. Detailed Implementation
[0051] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.
[0052] Please see Figure 1 , Figure 1 This is a schematic diagram of a photovoltaic-storage system (PV-SES) network in a large-scale ground-mounted power station or industrial / commercial application scenario, provided in one embodiment of this application. The PV-SES system includes a power conversion device 100, photovoltaic modules 200, a prefabricated substation 300, a booster station 400, a power grid 500, and an energy storage system 600. The photovoltaic modules 200 convert solar energy into direct current (DC) through the photovoltaic effect. A photovoltaic inverter 101 converts the DC output from the photovoltaic modules 200 into alternating current (AC) and further transmits the AC to the prefabricated substation 300. The prefabricated substation 300 converts the low-voltage AC output from the photovoltaic inverter 101 into medium-voltage AC and further transmits the AC to the booster station 400 (power grid 500) or the prefabricated substation 300 corresponding to the energy storage system 600. The energy storage system 600 stores the unstable electrical energy from the photovoltaic modules 200 and, through the energy storage converter 102 and the corresponding prefabricated substation 300, outputs stable electrical energy to the power grid 500. It is understood that the energy storage system 600 includes an energy storage battery, and the DC power from the energy storage battery is converted into AC power by the energy storage converter 102.
[0053] Figure 1 In the photovoltaic-storage system shown, the photovoltaic inverter 101 and the energy storage converter 102 are the core devices for power conversion, and they are collectively referred to as the power conversion device 100. The power conversion device 100 provided in this application can also be applied to residential photovoltaic systems, because the grid connection method of residential photovoltaic systems is different from... Figure 1 The similarities are not repeated here.
[0054] Please see Figure 2 , Figure 2 This is a schematic diagram of a power conversion device 100 provided in one embodiment of this application. Figure 2 As shown, the power conversion device 100 includes a power module 10 and a circuit board 20, wherein the power module 10 is electrically connected to the circuit board 20. The circuit board 20 includes, but is not limited to, a ceramic circuit board, an alumina ceramic circuit board, or an aluminum nitride ceramic circuit board.
[0055] This application also provides a power module 10. The power module 10 includes a substrate 11, a chip 12, ejector pins 13, and a molding compound 14. Both the chip 12 and the ejector pins 13 are electrically connected to the substrate 11. The extension direction of the ejector pins 13 is parallel to the stacking direction of the substrate 11 and the chip 12. The molding compound 14 encapsulates the chip 12 and a portion of the ejector pins 13.
[0056] The power module 10 includes, but is not limited to, an insulated gate bipolar transistor (IGBT) module and a silicon carbide (SiC) module. In this application, after the power module 10 is encapsulated using a packaging mold, the power module 10 does not require a cover plate, which helps to reduce costs.
[0057] The substrate 11 can be a thin-film ceramic substrate, a thick-film printed ceramic substrate, a directly bonded copper ceramic substrate, a directly aluminum-clad ceramic substrate, or an active metal-bonded ceramic substrate. The substrate 11 is soldered and fixed to the chip 12. The chip 12 has functions of power conversion, power amplification, control of power supply current, and protection.
[0058] Power modules play a crucial role in power conversion devices, serving as key components for energy conversion, power amplification, power control, and protection. Top-mounted pins are a common structure in power modules, facilitating quick and easy crimping or soldering. In top-mounted pin power modules, the pin tops protrude above the module surface. To prevent interference between the upper cavity and the pins during mold closing, clearance holes are cut into the upper cavity at the corresponding pin positions. During mold closing, the portion of the pin above the module surface enters these clearance holes. Currently, top-mounted pin power modules require a cover plate during molding to block the flow of molding compound. The cover plate and the molded power module then form a complete module. Furthermore, the clearance holes in the cover plate need to be sealed to prevent excess compound from overflowing from the ejector pins. Therefore, the cover plate typically consists of a substrate and a silicone pad. The silicone pad adhered to the substrate ensures an interference fit between the ejector pins and the silicone pad, preventing molding compound from leaking out from the gap between the ejector pins and the cover plate. Since both the substrate and the silicone pad are injection molded, the overall production cycle of the cover plate is long.
[0059] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a packaging mold 30 provided in an embodiment of this application. This application provides a packaging mold 30, which includes a first mold 31, a second mold 32, and a third mold 33. During use, the first mold 31, the second mold 32, and the third mold 33 are stacked sequentially. The first mold 31 is used to fix the object to be molded, wherein the object to be molded may include a molding device with protruding signal terminals or other pin-shaped or columnar terminal structures. For example, the object to be molded may be a molding-encapsulated power module with pins protruding from the top, and the power module to be molded includes, for example, a molding-encapsulated power module with pins protruding from the top. Figure 2The substrate 11, chip 12, and ejector pin 13 shown do not have a molding compound 14 formed on them. A second mold 32 is detachably fitted onto the first mold 31. When the second mold 32 and the first mold 31 are fitted together, they form a receiving cavity 34 for placing the object to be molded. The projected area of the second mold 32 on the first mold 31 is larger than the projected area of the object to be molded on the first mold 31. The second mold 32 has a clearance hole 321 communicating with the receiving cavity 34. The clearance hole 321 penetrates both opposite sides of the second mold 32 and is used for the ejector pin 13 to pass through. A flexible filler 35 is provided between the second mold 32 and the third mold 33. For example, the side of the second mold 32 facing away from the first mold 31 is used to place the flexible filler 35. At least a portion of the flexible filler 35 is used to fill the gap between the ejector pin 13 and the sidewall of the clearance hole 321. The power module 10 provided in this embodiment is made by the packaging mold 30 provided in this embodiment.
[0060] In this application, the second mold 32 serves to position the ejector pin 13 of the object to be molded and to place the flexible filler 35. The projected area of the second mold 32 on the first mold 31 is larger than the projected area of the object to be molded on the first mold 31. After the second mold 32 and the first mold 31 are closed, the entire part of the object to be molded, except for the ejector pin 13, can be contained in the receiving cavity 34. When the molding compound is injected into the receiving cavity 34, it is ensured that the molding compound can cover the edge of the object to be molded. Without the need for a cover plate, the flexible filler 35 can fill the gap between the ejector pin 13 and the side wall of the clearance hole 321 under the force applied by the third mold 33, so that the flexible filler 35 can tightly wrap the ejector pin 13, preventing the molding compound from flowing out from the gap between the ejector pin 13 and the side wall of the clearance hole 321, and ensuring that there is no excess glue around the ejector pin 13. Furthermore, using a cover plate to block the flow of molding compound and prevent overflow at the ejector pins suffers from problems such as low opening accuracy and complex structure due to the influence of the injection molding mold on the cover plate. The second mold 32 of this application does not require molding with silicone, has a simple structure, and solves the problem of opening accuracy being affected by the mold. Both the second mold 32 and the flexible filler 35 can be reused or replaced. The flexible filler 35 does not require pre-molding, which can effectively shorten the production cycle of the object to be molded and help reduce costs.
[0061] For example, the first mold 31 may include a bottom wall and a side wall, with the side wall connected to the outer peripheral edge of the bottom wall. The side wall and the bottom wall may be integrally molded, reducing assembly steps. The bottom wall or the side wall may have an injection port for injecting molding compound into the receiving cavity 34. The second mold 32 abuts against the end of the side wall away from the bottom plate, and the second mold 32, the side wall, and the bottom wall together form the receiving cavity 34.
[0062] The second mold 32 is detachably connected to the first mold 31, facilitating the replacement of the second mold 32. The second mold 32 includes a first surface 322 and a second surface 323. The first surface 322 and the second surface 323 are arranged opposite to each other along the stacking direction of the first mold 31 and the second mold 32, with the first surface 322 facing the first mold 31.
[0063] For example, the second mold 32 can be a flat plate structure, that is, the cross-sectional shape of the second mold 32 is "I" shaped, and the first surface 322 directly contacts the first mold 31. Alternatively, the cross-sectional shape of the second mold 32 can also be "H" shaped, that is, both the edges of the first surface 322 and the second surface 323 are provided with protruding structures, and the protruding structure on the first surface 322 abuts against the side wall of the first mold 31. Alternatively, the cross-sectional shape of the second mold 32 can also be "U" shaped, that is, one of the first surface 322 and the second surface 323 is provided with a protruding structure, for example, the first surface 322 is provided with a protruding structure, and this protruding structure abuts against the side wall of the first mold 31. The cross-sectional shape of the second mold 32 can also be other shapes, which are not specifically limited.
[0064] Specifically, the clearance hole 321 penetrates the first surface 322 and the second surface 323. A portion of the ejector pin 13 of the object to be molded is housed in the receiving cavity 34. When the first mold 31 and the second mold 32 are closed, the portion of the ejector pin 13 that is higher than the second surface 323 passes through the clearance hole 321 and is located on the side of the second surface 323 away from the first surface 322.
[0065] The opening shape of the clearance hole 321 can be rectangular, circular, elliptical, triangular, trapezoidal, rhomboid or polygonal. The opening shape of the clearance hole 321 can be made according to the specific shape of the ejector pin 13 and is not limited.
[0066] In one embodiment, the clearance hole 321 includes a first hole segment 3211 and a second hole segment 3212. The first hole segment 3211 and the second hole segment 3212 are arranged along the stacking direction of the first mold 31 and the second mold 32. Along the stacking direction of the first mold 31 and the second mold 32, the first hole segment 3211 is closer to the first mold 31 than the second hole segment 3212. The diameter of the first hole segment 3211 is larger than the diameter of the second hole segment 3212. For example, the clearance hole 321 is generally a trumpet-shaped hole or a stepped hole that is narrower at the top and wider at the bottom. The ejector pin 13 of the object to be molded passes through the first hole segment 3211 and the second hole segment 3212 in sequence and extends to the side of the second mold 32 away from the first mold 31. The first hole segment 3211, with its larger diameter, can guide the ejector pin 13 of the object to be molded, making it easier for the ejector pin 13 to pass through and effectively reducing assembly accuracy.
[0067] The second mold 32 has multiple clearance holes 321. The number of clearance holes 321 is greater than the number of multiple ejector pins 13 of the object to be molded. The multiple clearance holes 321 are adapted to the multiple ejector pins 13 of at least two objects to be molded.
[0068] Please see Figure 3 and Figure 4 , Figure 4 This is a top view of a second mold 32 provided in one embodiment of this application. Specifically, a plurality of clearance holes 321 are arranged at intervals, for example, in a matrix arrangement. The matrix arrangement of the clearance holes 321 can form different combinations of arrangements to accommodate materials to be molded at different positions of the ejector pins 13. This reduces the frequency of changing the second mold 32 and improves the adaptability of the encapsulation mold 30, which helps to shorten the manufacturing cycle of the encapsulation mold 30 and reduce its manufacturing cost. It is understood that during the encapsulation process, excessive clearance holes 321 not penetrated by the ejector pins 13 are filled with flexible filler 35, preventing the encapsulating material from overflowing from these clearance holes 321.
[0069] The number of second molds 32 is at least two, and each second mold 32 is provided with multiple clearance holes 321. The arrangement of the multiple clearance holes 321 in each second mold 32 is different. For example Figure 5 As shown, Figure 5 This is a top view of another second mold 32 provided in one embodiment of this application. The opening design on a second mold 32 is only applicable to the same type of object to be molded, that is, the number of multiple clearance holes 321 on the second mold 32 is equal to the number of multiple ejector pins 13 of the same series of objects to be molded. In this way, when molding an object to be molded that is adapted to this second mold 32, the multiple ejector pins 13 correspond one-to-one with the multiple clearance holes 321, and during injection molding of the molding compound, it can be prevented that the molding compound overflows from too many clearance holes 321 that are not penetrated by the ejector pins 13. When molding other series of objects to be molded, a second mold 32 with a number of ejector pins 13 corresponding one-to-one with the object to be molded can be replaced.
[0070] In this application, a second mold 32 is designed for the ejector pin 13 position of different series of objects to be molded. In this way, a series of objects to be molded with different ejector pin 13 positions can be adapted by different customized second molds 32. When molding different objects to be molded, the second mold 32 that is adapted to it can be replaced without replacing the entire set of packaging molds 30. It can also reduce the repeated development of the first mold 31 and the third mold 33, which is conducive to reducing costs.
[0071] Please see Figure 6 , Figure 6This is a schematic diagram of the structure of the first mold 31 and the second mold 32 before mold closing, according to an embodiment of this application. Along the stacking direction of the first mold 31 and the second mold 32, the orthogonal projection of the flexible filler 35 covers the clearance holes 321. For example, the flexible filler 35 can cover the entire surface of the second surface 323, ensuring that the flexible filler 35 completely covers all clearance holes 321. With this configuration, when the third mold 33 applies a force towards the first mold 31 to the flexible filler 35, the flexible filler 35 can fill all clearance holes 321, effectively preventing molding compound from entering the clearance holes 321 and causing excess adhesive.
[0072] The flexible filler 35 can have a layered structure. The flexible filler 35 includes materials such as rubber or silicone, and under the action of the third mold 33, it can undergo elastic deformation to fill the gap between the ejector pin 13 and the sidewall of the clearance hole 321, thus sealing the clearance hole 321. The flexible filler 35 also has high-temperature resistance to prevent it from melting during molding and reducing the sealing performance of the clearance hole 321.
[0073] Please see Figure 7 , Figure 7 This is a schematic diagram of the encapsulation mold 30 after mold closing, according to an embodiment of this application. Further, along the stacking direction of the first mold 31 and the second mold 32, the orthographic projection of the third mold 33 covers the orthographic projection of the flexible filler 35. For example, the orthographic projection of the third mold 33 is greater than or equal to the orthographic projection of the flexible filler 35. With this configuration, the third mold 33 can apply force to the entire surface of the flexible filler 35, ensuring that the flexible filler 35 can fully fill all the clearance holes 321, preventing adhesive overflow at the clearance holes 321.
[0074] For example, the dimension of the flexible filler 35 on the side of the second mold 32 facing away from the first mold 31 along the stacking direction of the first mold 31 and the second mold 32 is greater than the dimension of the ejector pin 13 on the side of the second mold 32 facing away from the first mold 31 along the stacking direction of the first mold 31 and the second mold 32. That is, along the stacking direction of the first mold 31 and the second mold 32, the dimension of the flexible filler 35 on the side of the second surface 323 facing away from the first surface 322 is greater than the dimension of the ejector pin 13 on the side of the second surface 323 facing away from the first surface 322. The ejector pin 13 of the object to be molded will not penetrate the flexible filler 35. With this configuration, when the third mold 33 applies a force toward the first mold 31 to the flexible filler 35, the third mold 33 will not squeeze the ejector pin 13 that extends beyond the second surface 323. In addition, along the stacking direction of the first mold 31 and the second mold 32, the flexible filler 35 has a larger size, which ensures that the flexible filler 35 can fill the gap between the ejector pin 13 and the side wall of the clearance hole 321 more quickly under the force applied by the third mold 33, which is beneficial to shorten the production cycle of the object to be sealed.
[0075] Please see Figure 8 and Figure 9 , Figure 8 This is a schematic diagram of the structure of a packaging mold 30 provided in an embodiment of this application. Figure 9 This is a schematic diagram of another packaging mold 30 provided in an embodiment of this application. The packaging mold 30 further includes a limiting member 36, which is disposed around the flexible filler 35 and limits the flexible filler 35. The limiting member 36 is disposed on the surface edge of the second mold 32 away from the first mold 31, and / or, the limiting member 36 is disposed on the surface edge of the third mold 33 facing the second mold 32. The limiting member 36 may be the aforementioned protruding structure.
[0076] Specifically, the limiting member 36 is disposed at the edge of the second surface 323, and / or, the limiting member 36 is disposed at the surface edge of the third mold 33 facing the second mold 32, for example, as... Figure 7 As shown, the limiting member 36 is disposed on the circumferential edge of the second surface 323. The limiting member 36 disposed on the second surface 323 can be integrally formed with the second mold 32, that is, the cross-sectional shape of the second mold 32 is "U-shaped". The limiting member 36 on the second surface 323 can also be a separate structure from the second mold 32, which is not specifically limited. For example, the limiting member 36 is disposed on the circumferential edge of the surface of the third mold 33 facing the second mold 32. The limiting member 36 disposed on the third mold 33 can be integrally formed with the third mold 33, or it can be a separate structure. For example, such as... Figure 8 As shown, the limiting member 36 is provided on the circumferential edge of the second surface 323, and is also provided on the circumferential edge of the surface of the third mold 33 facing the first mold 31. That is, both the second mold 32 and the third mold 33 are provided with the limiting member 36.
[0077] The flexible filler 35 placed on the second surface 323 is limited by the limiting member 36 to prevent the flexible filler 35 from being squeezed outside the edge of the second mold 32 when the third mold 33 applies a force toward the first mold 31, thus ensuring that the flexible filler 35 can fully fill the gap between the ejector pin 13 and the side wall of the clearance hole 321.
[0078] The third mold 33 is used to apply a force toward the first mold 31 to the flexible filler 35 so that at least a portion of the flexible filler 35 fills the gap between the ejector pin 13 and the sidewall of the clearance hole 321.
[0079] In one embodiment, the third mold 33 is a flat plate structure. In this case, a limiting member 36 is provided on the second surface 323. When the third mold 33 and the second mold 32 are closed, the third mold 33 is located entirely within the space enclosed by the limiting member 36 and the second mold 32, which facilitates the third mold 33 to apply a force toward the first mold 31 to the flexible filler 35, ensuring that the flexible filler 35 can fill the clearance hole 321.
[0080] like Figure 9 As shown, in another embodiment, the third mold 33 includes a fixing plate 331 and a protrusion 332. The protrusion 332 is disposed on the side of the fixing plate 331 facing the second mold 32, and is used to directly apply a force toward the first mold 31 to the flexible filler 35. Wherein, when the encapsulation mold 30 is provided with a limiting member 36, the protrusion 332 is located within the space enclosed by the limiting member 36.
[0081] Please see Figure 10 and Figure 11 , Figure 10 This is a schematic flowchart illustrating the fabrication method of the power module 10 provided in an embodiment of this application. Figure 11 This is a schematic diagram of a power module 10 encapsulated by a packaging mold 30 according to an embodiment of this application. This application also provides a method for fabricating the power module 10, which includes steps S101-S105, specifically:
[0082] S101: Place the object to be sealed onto the first mold 31.
[0083] The object to be laminated can be a power module, including, for example, [examples of such modules]. Figure 2 The substrate 11, chip 12 and ejector pin 13 shown do not have a molding layer 14 formed.
[0084] S102: Place flexible filler 35 on the second mold 32.
[0085] like Figure 3 As shown, the flexible filler 35 covers all the clearance holes 321 on the second mold 32 to ensure that there will be no overflow of glue from the clearance holes 321 during subsequent injection molding of the sealing material.
[0086] S103: The first mold 31 and the second mold 32 are closed, wherein the ejector pin 13 of the object to be molded passes through the clearance hole 321 of the second mold 32.
[0087] After the second mold 32 and the first mold 31 are closed, the ejector pin 13 of the object to be molded passes through the clearance hole 321 on the second mold 32 and extends to the side of the second mold 32 away from the first mold 31.
[0088] It is understood that in this embodiment, the order of the sequence numbers of the above processes does not imply the order of execution. For example, step S103 can be executed before S102, after S102, or simultaneously with S102. The execution order of each process should be determined by its function and internal logic, and should not limit the implementation process of this embodiment.
[0089] S104: Close the third mold 33 and the second mold 32, and apply a force toward the first mold 31 to the flexible filler 35 through the third mold 33 so that at least part of the flexible filler 35 fills the gap between the ejector pin 13 and the side wall of the clearance hole 321.
[0090] like Figure 7 As shown, after the third mold 33 and the second mold 32 are closed, the third mold 33 will not touch the ejector pin 13 along the stacking direction of the first mold 31 and the second mold 32. Specifically, by controlling the size of the flexible filler 35 along the stacking direction of the first mold 31 and the second mold 32, it is ensured that when the third mold 33 applies force to the flexible filler 35, the flexible filler 35 can fill the gap between the ejector pin 13 and the side wall of the clearance hole 321, while the third mold 33 will not touch the ejector pin 13.
[0091] S105: Molding material is injected into the receiving cavity 34 formed by the first mold 31 and the second mold 32 to form the power module 10.
[0092] like Figure 11 As shown, specifically, when at least a portion of the flexible filler 35 fills the gap between the ejector pin 13 and the sidewall of the clearance hole 321 and / or the clearance hole 321 where the ejector pin 13 does not pass through, a high-temperature molten molding compound (such as epoxy resin) is injected into the receiving cavity 34, ensuring that the molding compound completely encapsulates the chip 12. The molding compound injected into the receiving cavity 34 is further cured by heating, so that the resulting molding layer 14 has sufficient hardness and strength to effectively protect the chip 12 and prevent damage to the chip 12 from the external environment.
[0093] In this application, unless otherwise expressly specified and limited, the terms "connection" and "fixed" shall be interpreted broadly. For example, "fixed" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction between two elements, unless otherwise expressly limited.
[0094] Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. The use of "first," "second," and various numerical designations herein is for descriptive convenience only and is not intended to limit the scope of this application.
[0095] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0096] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A packaging mold, characterized in that, The packaging mold includes a first mold, a second mold, and a third mold, which are stacked sequentially. The first mold and the second mold cover are combined to form a receiving cavity for placing the object to be molded. The orthographic projection area of the second mold on the first mold is larger than the orthographic projection area of the object to be molded on the first mold. The second mold has a clearance hole communicating with the receiving cavity. The clearance hole extends through both opposite sides of the second mold and is used for the ejector pin of the object to be molded to pass through. A flexible filler is provided between the second mold and the third mold. At least part of the flexible filler is used to fill the gap between the ejector pin and the sidewall of the clearance hole.
2. The packaging mold according to claim 1, characterized in that, The dimension of the flexible filler on the side of the second mold opposite to the first mold along the stacking direction of the first mold and the second mold is greater than the dimension of the ejector pin on the side of the second mold opposite to the first mold along the stacking direction of the first mold and the second mold.
3. The packaging mold according to claim 2, characterized in that, The packaging mold further includes a limiting member, which is disposed around the flexible filler and limits the flexible filler. The limiting member is disposed on the surface edge of the second mold away from the first mold, and / or, the limiting member is disposed on the surface edge of the third mold facing the second mold.
4. The packaging mold according to claim 1, characterized in that, Along the stacking direction of the first mold and the second mold, the orthogonal projection of the flexible filler covers the clearance hole.
5. The packaging mold according to claim 4, characterized in that, Along the stacking direction of the first mold and the second mold, the orthographic projection of the third mold covers the orthographic projection of the flexible filler.
6. The packaging mold according to claim 1, characterized in that, The clearance hole includes a first hole segment and a second hole segment. The first hole segment and the second hole segment are arranged along the stacking direction of the first mold and the second mold. Along the stacking direction of the first mold and the second mold, the first hole segment is closer to the first mold than the second hole segment. The diameter of the first hole segment is larger than the diameter of the second hole segment.
7. The packaging mold according to claim 1, characterized in that, The number of the second molds is at least two, and each second mold is provided with a plurality of the clearance holes, and the arrangement of the plurality of clearance holes in each second mold is different.
8. The packaging mold according to claim 1, characterized in that, The number of clearance holes is multiple, and the number of clearance holes is greater than or equal to the number of ejector pins of the object to be laminated. The multiple clearance holes are adapted to at least two ejector pins of the object to be laminated.
9. The packaging mold according to claim 1, characterized in that, The flexible filler includes rubber or silicone.
10. A power module, characterized in that, The power module is manufactured using the packaging mold as described in any one of claims 1-9. The power module includes a substrate, a chip, ejector pins, and a molding compound. The chip and ejector pins are both electrically connected to the substrate. The extension direction of the ejector pins is parallel to the stacking direction of the substrate and the chip. The molding compound encapsulates the chip and part of the ejector pins.
11. A power conversion device, characterized in that, It includes a circuit board and a power module as described in claim 10, wherein the power module is connected to the circuit board.