A power module and a mold for manufacturing the same, an apparatus

Abstract

A power module and a preparation mold and equipment, the power module includes a substrate (10), the substrate (10) is used as a bearing structure to bear the device (30) and the pin (50) of the power module.The substrate (10) is provided with a circuit layer to complete the electrical connection between the bearing device (30).The device (30) and the pin (50) are arranged on the same surface of the substrate (10), and the device (30) and the pin (50) are electrically connected through the substrate (10).The power module further comprises a sealing layer (60), the sealing layer (60) is sleeved on the pin (50), the pin (50) is partially exposed on the side of the sealing layer (60) away from the substrate (10), and the sealing layer (60) and the substrate (10) form a space for accommodating the plastic sealing layer (80).In order to protect the safety of the device, the power module further comprises a plastic sealing layer (80), which is filled between the sealing layer (60) and the substrate (10).The plastic sealing layer (80) is made of thermosetting material, which can be packaged by injection molding.The thermosetting material has good waterproof and moisture-proof performance, which improves the waterproof and moisture-proof effect of the power module and improves the protection effect of the power module.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power module and a manufacturing mold and equipment. Background Art

[0002] A power module is a combination of power components that are packaged into a module according to certain functions. It is widely used in servo motors, frequency converters, inverters and other fields. The top-out pin (pin) is a common structure in power modules, which can facilitate quick crimping or welding at the system end. The existing packaging form of high-power modules with top-out pins is mainly a packaging that is first bonded to the shell and then injection molded. After the copper-clad ceramic substrate, chip, and pin assembly and welding are completed, silicone gel is poured to protect the components. Figure 1 The prior art shown uses a power module that is first bonded to a housing and then injection molded. The power module includes a substrate 1, a chip 2 and pins 3 disposed on the substrate 1, wherein the chip 2 is electrically connected to the substrate 1 via bonding wires, and the pins 3 are electrically connected to the substrate 1 via pads. The power module also includes an encapsulation layer 5 that wraps around the chip 2 and a portion of the pins 3. The power module also includes a housing 4 that covers the encapsulation layer 5, with the ends of the pins 3 passing through the substrate 1 and exposed. When the above-mentioned method of bonding the housing first and then injection molding is used, the reliability performance is relatively weak due to the material properties of silicone gel, especially the waterproof and vapor-proof performance. Summary of the Invention

[0003] The present application provides a power module and a manufacturing mold and equipment to improve the performance of the power module.

[0004] In a first aspect, a power module is provided for use in applications such as servo motors, frequency converters, and inverters. The power module includes a substrate, which serves as a supporting structure for the power module's components and pins. The substrate may also support other components as required by the power module. The substrate is provided with a circuit layer to electrically connect the components. The components and pins are arranged on the same surface of the substrate, and the components and pins are electrically connected through the substrate. The power module also includes a sealing layer spaced apart from the substrate, with a filler space between the substrate and the sealing layer. The power module also includes a plastic encapsulation layer, which fills the filler space between the substrate and the sealing layer and encapsulates the components and pins. The pins extend through the sealing layer and the plastic encapsulation layer and are electrically connected to the substrate, with the pin portions exposed on the side of the sealing layer facing away from the plastic encapsulation layer. When the plastic encapsulation layer is used to encapsulate the components, the plastic encapsulation layer is made of a thermosetting material. Thermosetting materials can be encapsulated by injection molding. Furthermore, thermosetting materials have excellent waterproof and moisture-proof properties, improving the waterproof and moisture-proof properties of the power module and enhancing the protection of the power module.

[0005] In one specific embodiment, the sealing layer has a boss structure on the side facing away from the plastic layer, corresponding to each pin. Each pin passes through the corresponding boss structure. The boss structure increases the contact area with the pin and reduces glue overflow during injection molding of the plastic layer.

[0006] In a specific embodiment, each pin has a limiting structure, and the side of the sealing layer facing the plastic layer is pressed against the limiting structure, which facilitates limiting the position of the sealing layer and increases the contact area between the sealing layer and the pin.

[0007] In a specific embodiment, the limiting structure is a step structure or a terrace structure. The limiting structure can be formed by different structures.

[0008] In a specific embodiment, the plastic encapsulation layer partially extends beyond the sealing layer, and the extended portion of the plastic encapsulation layer at least wraps around the sidewalls of the sealing layer. By wrapping the sidewalls of the sealing layer with the plastic encapsulation layer, the waterproof and moisture-proof effects of the power module are improved.

[0009] In a specific embodiment, the extension of the plastic encapsulation layer wraps around the substrate and the sidewall of the sealing layer, thereby improving the waterproof and moisture-proof effects of the power module.

[0010] In a specific embodiment, the cross section of the plastic encapsulation layer is H-shaped, and the plastic encapsulation layer has two vertical portions exposed outside the substrate, thereby improving the safety of the power module.

[0011] In a specific embodiment, the power module further includes a cover plate, which covers the sealing layer and is in pressing contact with the sealing layer; the pins pass through the cover plate and are exposed on a side of the cover plate facing away from the plastic encapsulation layer, thereby improving the safety of the power module.

[0012] In a specific embodiment, when the sealing layer has a boss structure, the cover plate is provided with a receiving groove that cooperates with the boss structure, so as to facilitate the cooperation between the cover plate and the sealing layer.

[0013] In a specific embodiment, the boss structure is interference-fitted with the receiving groove, and the sealing layer is squeezed by the cover plate, thereby improving the sealing effect between the pin and the sealing layer.

[0014] In a specific embodiment, the boss structure is a circular boss, and the corresponding receiving groove is a circular groove, so as to facilitate the matching between the sealing layer and the cover plate.

[0015] In a specific embodiment, the plastic sealing layer wraps the side wall of the cover plate, thereby further improving the safety of the power module.

[0016] In a specific embodiment, the plastic sealing layer is made of EMC plastic sealing material, which has good waterproof and moisture-proof effects.

[0017] In a specific embodiment, the EMC molding compound can be different materials such as bisphenol A epoxy resin or polyol epoxy resin. The molding layer can be prepared by using different materials.

[0018] In a second aspect, a preparation mold is provided, which is used to prepare any of the power modules described above. The preparation mold includes an upper mold and a lower mold covering the upper mold; wherein the upper mold includes a fixed base and an upper mold core detachably connected to the fixed base;

[0019] The upper mold core is provided with a clearance hole for the pins. When the upper and lower molds are closed, the upper mold core and lower mold press against each other, forming a space for filling with thermosetting material. The removable upper mold core and the fixed base allow for replacement of the upper mold core according to the power module to be molded, facilitating power module production.

[0020] In a specific embodiment, when the power module includes a cover plate, the upper mold core is provided with a positioning column, and the cover plate is provided with a positioning groove that cooperates with the positioning column, thereby improving alignment during production.

[0021] In a specific embodiment, the upper mold core can be detachably connected to the fixing seat via a threaded connection member, which includes but is not limited to a screw, a bolt, or a bolt assembly.

[0022] In a third aspect, a device is provided, comprising a power module and any of the aforementioned power modules connected to the power module. By encapsulating the pins with a plastic layer, the power module is protected from water and moisture, thereby improving protection and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of a power module in the prior art;

[0024] Figure 2 A structural diagram of a power module provided in an embodiment of the present application;

[0025] Figure 3 for Figure 2 Cross-sectional view at AA in the middle;

[0026] Figure 4 A schematic structural diagram of the sealing layer provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of the cooperation between the sealing layer and the pin provided in an embodiment of the present application;

[0028] Figure 6 A schematic structural diagram of another power module provided in an embodiment of the present application;

[0029] Figure 7 A schematic diagram of the structure of the cover plate provided in an embodiment of the present application;

[0030] Figure 8 A schematic structural diagram of another power module provided in an embodiment of the present application;

[0031] Figure 9a to Figure 9g A method for preparing a power module according to an embodiment of the present application;

[0032] Figure 10 The preparation mold provided in the embodiment of the present application;

[0033] Figure 11 An exploded schematic diagram of the upper mold provided in an embodiment of the present application;

[0034] Figure 12 A schematic structural diagram of the upper mold core provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] First, let’s explain the power module. The power module is a module that is composed of power electrical devices that are combined according to certain functions and then encapsulated. It is widely used in the fields of servo motors, frequency converters, inverters, etc. The power module may include various active and passive devices, chips, isolated components or component packages (packaged chips) and other different devices. The above devices are combined according to the required functions to form a module with certain functions. When the power module is applied to products such as servo motors, frequency converters, inverters, etc., the working environment is poor and it will face adverse factors such as high humidity, high temperature difference, and high dust. In order to make the power module work reliably, the devices in the power module need to be encapsulated to ensure the reliable operation of the power module. The power module in the prior art usually adopts Housing packaging, but due to the limitation of the material of silicone gel, the waterproof and moisture-proof performance of the power module is poor. For this reason, the embodiment of the present application provides a power module with improved moisture-proof performance. The following is a detailed description of it in conjunction with specific drawings and embodiments.

[0036] Figure 2The schematic diagram of the structure of the power module provided by the embodiment of the present application is shown. The power module provided by the embodiment of the present application includes a substrate 10, a plastic encapsulation layer 80, a sealing layer 60 and a pin 50. Among them, the substrate 10 serves as a bearing structure for carrying the device 30 and the pin 50. In addition, the substrate 10 can also electrically connect the devices 30 to form the circuit required for the power module. The plastic encapsulation layer 80 is used to encapsulate the device 30 and the pin 50 to improve the waterproof and moisture-proof performance of the power module. The sealing layer 60 is used to seal the pin 50 to facilitate the injection molding of the plastic encapsulation material. The structure and function of each component of the power module are described in detail below with reference to the accompanying drawings.

[0037] Figure 3 Show Figure 2 The cross-sectional view at AA in FIG. First, the substrate 10 is described. The surface of the substrate 10 can be used as the bearing surface of the bearing device 30. One surface of the substrate 10 can be used as the bearing surface, or two opposite surfaces of the substrate 10 can be used as the bearing surface. For example, Figure 2 It is shown that one surface of the substrate 10 is used as the bearing surface, and the device 30 and the pin 50 are arranged on the same bearing surface of the substrate 10 .

[0038] The substrate 10 has a circuit layer ( Figure 3 (not shown in the figure), the circuit layer includes a metal circuit layer arranged on the surface of the substrate 10 or in the substrate 10 and a plurality of pads 20 electrically connected to the metal circuit layer. The plurality of pads 20 are located on the bearing surface of the substrate 10 and are used to connect to the device 30 and the pins 50 carried by the substrate 10. The plurality of pads 20 can be divided into first pads and second pads according to their functions. The pads 20 connected to the pins 50 are first pads, and the pads 20 connected to the device 30 are second pads. When the device 30 and the pins 50 are arranged on the bearing surface, on the one hand, the pins 50 and the device 30 are respectively fixed to the bearing surface through the corresponding pads 20, and on the other hand, the pins 50 and the device 30 are respectively electrically connected to the circuit layer of the substrate 10 through the corresponding pads 20.

[0039] As an optional solution, the device 30 can also be connected to the circuit layer of the substrate 10 through a bonding wire 40. Figure 3 As shown in FIG, one end of the bonding wire 40 is electrically connected to the surface of the device 30 away from the substrate 10, and the other end is connected to the pad 20 on the substrate 10. The device 30 can be electrically connected to the circuit layer through the bonding wire 40 and the second pad. Figure 3 The example in which the device 30 is connected to the circuit layer of the substrate 10 via one bonding wire 40 is only shown. However, in the embodiment of the present application, the number of bonding wires 40 is not specifically limited. The device 30 can select different numbers of bonding wires 40 to be connected to the circuit layer of the substrate 10 according to its function.

[0040] The substrate 10 may be a substrate of different types, such as a printed circuit board or a circuit board with circuits laid thereon.

[0041] In the embodiment of the present application, the shape of the substrate 10 is not limited. The power module provided in the embodiment of the present application can be designed with the substrate 10 into shapes such as rectangle, oval, square, circle, special shape, etc. according to needs.

[0042] The device 30 provided in the embodiment of the present application can select different devices according to the function of the power module. For example, the device 30 can be various active devices, passive devices, chips, isolated components or component packages (packaged chips) and other different devices. It should be understood that although Figure 3 Two devices 30 are shown in the example, but the device 30 provided in the embodiment of the present application is not limited to Figure 3 The number of devices shown in Figure 3 This is only used to illustrate the connection method between the device 30 and the substrate 10, and does not represent the actual number of devices 30. The power module provided in the embodiment of the present application can have one, two, three, four or other different numbers of devices 30 according to its function.

[0043] The pin 50 provided in the embodiment of the present application is connected to the circuit layer of the substrate 10 through the first pad, and is electrically connected to the device 30 through the circuit layer of the substrate 10. The pin 50 serves as an external connection port of the power module and is used to connect to other modules that cooperate with the power module. Figure 3 As shown in FIG, the height direction of the pin 50 is perpendicular to the bearing surface of the substrate 10 and can extend to the outside of the power module. Figure 3 Three pins 50 are shown in the example, but the pins 50 provided in the embodiment of the present application are not limited to Figure 3 The number of pins shown in Figure 3 It is only used to illustrate the connection method between the pins 50 and the substrate 10, and does not represent the actual number of pins 50. The power module provided in the embodiment of the present application can select one, two, three, four or other different numbers of pins 50 according to its function.

[0044] As an alternative, the pins 50 can be made of conductive metals such as copper, aluminum, and alloys. These materials provide excellent electrical conductivity, elasticity, and rigidity, ensuring a secure connection between the power module and its mating module.

[0045] Along the height of the pin 50, the pin 50 can be divided into a packaging area and a connection area. The packaging area is the area where the pin 50 is encapsulated by the plastic layer 80 and the sealing layer 60; the connection area is the area where the pin 50 is exposed outside the sealing layer 60 and away from the plastic layer 80. The connection area is used to connect the power module with the matching module. It should be understood that the packaging area and connection area are divided according to the function of the pin 50 and do not mean that the pin 50 is composed of two parts. In the embodiment of the present application, the pin 50 is made of a metal material in one piece. The division of the above areas is only for the convenience of description.

[0046] The plastic encapsulation layer 80 provided in the embodiment of the present application is used to wrap the device 30 and the pin 50 provided on the substrate 10, so as to improve the moisture-proof, waterproof, dust-proof and other properties of the power module. The plastic encapsulation layer 80 provided in the embodiment of the present application is a plastic encapsulation layer made of a thermosetting material. Thermosetting material refers to a material that is solidified by heating when the material is in a liquid state. Compared with silicone gel, thermosetting material has better waterproof and moisture-proof effect. Exemplarily, the thermosetting material can be selected from EMC (Epoxy Injection Molding Compound, epoxy resin film) materials, such as bisphenol A epoxy resin or polyol epoxy resin and other different materials.

[0047] The power module provided in the embodiment of the present application further includes a sealing layer 60, which is spaced apart from the substrate 10. A filling space is provided between the substrate 10 and the sealing layer 60, and this space is used to fill a plastic encapsulation layer 80. During preparation, the plastic encapsulation layer 80 can fill the filling space between the substrate 10 and the sealing layer 60, thereby sealing the pins 50 and the device 30.

[0048] The distance between the sealing layer 60 and the substrate 10 can be used to limit the thickness of the molding layer 80 to prevent the molding layer 80 from molding the connection area of ​​the pin 50. When the molding layer 80 is prepared using a thermosetting material, the substrate 10 with the device 30 and the pin 50 is placed in a mold, and the upper mold and the lower mold are used to form a cavity for injection molding the molding layer 80. In order to ensure that the connection area of ​​the pin 50 is exposed outside the molding layer 80, the upper mold is provided with a avoidance hole for avoiding the pin 50. The sealing layer 60 is pressed against the upper mold to seal the avoidance hole of the upper mold to form a sealed cavity that can be injected with thermosetting material. After injection molding, the molding layer 80 is filled between the substrate 10 and the sealing layer 60. Due to the sealing effect of the sealing layer 60, the thermosetting material is prevented from overflowing to the connection area of ​​the pin 50.

[0049] Continue to refer Figure 3When the plastic encapsulation layer 80 is prepared, part of the plastic encapsulation layer 80 extends outward from the sealing layer 60, and the extended part of the plastic encapsulation layer 80 wraps the side wall of the sealing layer 60. The cross section of the plastic encapsulation layer 80 is concave, the sealing layer 60 is located in the recessed area in the middle of the plastic encapsulation layer 80, and the plastic encapsulation layer 80 wraps the side wall of the sealing layer 60. When the above structure is adopted, the plastic encapsulation layer 80 wraps the sealing layer 60, thereby increasing the contact area between the plastic encapsulation layer 80 and the sealing layer 60, and when the plastic encapsulation layer 80 is cured, the sealing layer 60 can be embedded in the plastic encapsulation layer 80 and sealed with the plastic encapsulation layer 80. The sealing layer 60 also serves as a sealing component of the entire power module, which can improve the waterproof, moisture-proof and dust-proof effects of the power module.

[0050] Figure 4 The schematic diagram of the sealing layer 60 provided in an embodiment of the present application is shown. Sealing layer 60 comprises a main structure 61, which is provided with through-holes 62 for each pin. When sealing layer 60 is fitted over the pins, each pin is inserted into each through-hole 62 in a one-to-one correspondence and forms a sealing contact with the sidewalls of through-hole 62.

[0051] As an optional solution, the surface of the sealing layer 60 facing away from the molding layer 80 is provided with a boss structure 63, corresponding one-to-one with each pin. The boss structure 63 is located on the surface of the main structure 61 facing away from the substrate. Each through-hole 62 passes through the main structure 61 and the boss structure 63. When a pin is inserted into a through-hole 62, the boss structure 63 increases the depth of the through-hole 62, thereby increasing the contact area between the pin and the sealing layer 60. This improves the seal between the pin 50 and the sealing layer 60 and prevents overflow of the molding compound during injection molding of the molding layer 80.

[0052] As an optional solution, the sealing layer 60 can be made of a material with good sealing performance, such as silicone, rubber, etc.

[0053] As an optional solution, when the sealing layer 60 and the pin are sealed, the pin and the through hole 62 can be interference fit, and the sealing layer 60 can achieve sealing with the pin through its own elastic properties, or the sealing layer 60 can be bonded to the pin through sealant to achieve sealing between the sealing layer 60 and the pin.

[0054] For reference Figure 5 , Figure 5A schematic diagram of the cooperation between the pins and the sealing layer is shown. Each pin 50 has a limiting structure 51 that limits the insertion depth of the sealing layer 60. The limiting structure 51 is arranged in the connection area of ​​the pin 50. When the sealing layer 60 is mounted on the pin 50, the side of the sealing layer 60 facing the plastic layer presses against the limiting structure 51, thereby limiting the depth of the sealing layer 60 inserted into the pin 50. It also ensures that the sealing layer 60 remains substantially parallel to the substrate 10 after being mounted on the pin 50, and forms a regular plastic layer 80-filled space with the substrate 10. In addition, the contact between the limiting structure 51 and the sealing layer 60 can also increase the contact area between the sealing layer 60 and the pin 50, further improving the sealing effect of the sealing layer 60.

[0055] Exemplarily, the limiting structure 51 of the pin 50 can adopt different structures, such as a trapezoidal structure, a step structure, etc. When the limiting structure 51 adopts a step structure, the step structure can be located outside the sealing layer 60, and the step surface of the step structure abuts the surface of the sealing layer 60 facing the substrate 10, and the through hole in the sealing layer 60 adopts a through hole with a constant diameter. Alternatively, the limiting structure 51 can also be inserted into the sealing gasket sealing layer 60. Specifically, the through hole 62 of the sealing gasket sealing layer 60 adopts a stepped hole, the opening direction of the first hole of the stepped hole is toward the substrate, and the opening direction of the second hole is away from the substrate, wherein the diameter of the first hole is larger than the diameter of the second hole. During assembly, the step surface of the step structure abuts against the step surface of the stepped hole. When the limiting structure 51 adopts a trapezoidal structure, the size of the trapezoidal structure gradually decreases in the direction away from the substrate. The through hole of the sealing gasket sealing layer 60 also adopts a matching trapezoidal hole. When the trapezoidal structure is inserted, the side wall of the trapezoidal structure contacts the side wall of the trapezoidal hole, and as the insertion depth of the sealing layer 60 increases, the contact pressure between the pin 50 and the sealing layer 60 gradually increases, thereby improving the sealing effect between the sealing layer 60 and the pin 50.

[0056] As an optional solution, when the limiting structure 51 is a stage-shaped structure, the limiting structure 51 can be a different stage-shaped structure such as a round stage-shaped structure, a square stage-shaped structure, etc.

[0057] Figure 6 A cross-sectional schematic diagram of another power module provided in an embodiment of the present application is shown. Figure 6 The middle part of the number can be referenced Figure 3 The same number in . Figure 6In addition to the substrate 10, device 30, pins 50, plastic encapsulation layer 80, and sealing layer 60, the power module also includes a cover plate 70. The cover plate 70 is mounted on the pins 50 and is located on the side of the sealing layer 60 facing away from the substrate 10. During assembly, the cover plate 70 is pressed against the sealing layer 60. The hardness of the cover plate 70 is greater than that of the sealing layer 60, so that the cover plate 70 can protect the sealing layer 60 and prevent the sealing layer 60 from being damaged. In addition, when preparing the injection molding layer, the upper mold can transfer force to the sealing layer 60 through the cover plate 70, and the cover plate 70 can serve as a support structure for the sealing layer 60.

[0058] As an optional solution, the cover plate 70 can be made of a material with relatively high hardness, such as plastic, resin, etc. The above materials all have relatively high hardness.

[0059] As an optional solution, when the cover plate 70 is stacked with the sealing layer 60, the cover plate 70 can be bonded to the sealing layer 60 by adhesive, thereby improving the stability of the connection between the cover plate 70 and the sealing layer 60.

[0060] As an optional solution, the portion of the plastic packaging layer 80 extending outward from the sealing layer 60 may further wrap the cover plate 70 and be connected and fixed to the cover plate 70 , which can further improve the waterproof and moisture-proof effects of the power module.

[0061] For reference Figure 7 , Figure 7 The cover plate 70 is provided with a plurality of through holes 71. The positions and number of the through holes 71 correspond to the positions and number of the pins to ensure that the cover plate 70 can be fitted over the pins.

[0062] As an optional solution, when the sealing layer has a boss structure, the cover plate 70 is provided with a receiving groove 72 that cooperates with the boss structure. During assembly, the cover plate 70 is attached to the sealing layer, and the boss structure of the sealing layer is inserted into the receiving groove 72 of the cover plate 70. When the boss structure adopts a different shape, the shape of the receiving groove 72 matches the shape of the boss structure so that the boss structure can be positioned in the receiving groove 72. For example, when the boss structure is a circular boss, the corresponding receiving groove 72 is a circular groove; or when the boss structure is a tapered boss, the corresponding receiving groove 72 is a tapered groove.

[0063] As an optional solution, the boss structure is interference fit with the corresponding receiving groove 72. When the cover plate 70 is assembled, the cover plate 70 can squeeze the boss structure to cause elastic deformation, thereby increasing the contact pressure between the pin and the boss structure and improving the sealing effect of the sealing layer on the pin.

[0064] It should be understood that the above-mentioned receiving grooves 72 correspond to the through holes 71 one by one, and the receiving grooves 72 are connected to the through holes 71 to ensure that the cover plate 70 can be assembled to the boss structure and the pins.

[0065] Figure 8 A cross-sectional schematic diagram of another power module provided in an embodiment of the present application is shown. Figure 8 The middle part of the number can be referenced Figure 6 The same number in . Figure 8 and Figure 6 The power modules shown differ in that the plastic encapsulation layer 80 is different. Figure 8 In the power module shown, the extension portion of the plastic encapsulation layer 80 wraps around the substrate 10 and the sidewalls of the sealing layer 60 .

[0066] The cross section of the plastic sealing layer 80 is H-shaped, which includes a horizontal portion and two vertical portions, wherein the horizontal portion is located between the sealing layer 60 and the substrate 10, and the two horizontal portions are located outside the substrate 10. Figure 2 The three-dimensional diagram of the power module shown in FIG can be understood. Figure 8 The plastic encapsulation layer 80 shown in the figure is located on the periphery of the power module. The vertical portions above form a frame structure, enclosing the substrate 10, the device 30, the pins 50, the sealing layer 60 and the cover 70 within the frame structure, thereby improving the waterproof and moisture-proof effects of the power module.

[0067] In addition, the plastic layer 80 is used Figure 8 In the structure shown, the vertical portion can also protect the substrate 10 and increase the insulation withstand voltage capability.

[0068] As an optional solution, the width of the vertical portion of the plastic packaging layer 80 is not less than 1 mm. For example, the width of the vertical portion of the plastic packaging layer 80 may be 2 mm.

[0069] To facilitate understanding of the structure of the power module provided in the embodiments of the present application, the preparation method thereof is described below with reference to the accompanying drawings.

[0070] Step 001: Solder placement on substrate.

[0071] like Figure 9a As shown, the substrate 10 may be a printed circuit board or other types of substrates. Regardless of the type of substrate used, the substrate 10 includes at least one metal circuit layer. The at least one metal circuit layer includes a circuit layer and a ground layer for electrically connecting to the device. In addition, a plurality of pads 20 are provided on the substrate 10, including but not limited to pads 20 for electrically connecting to the device, and pads 20 for electrically connecting to the pins. When solder is mounted on the substrate 10, the solder is connected to the pads 20 corresponding to the device 30 and the pin 50. The specific solder mounting may include solder paste printing or solder sheet, solder wire mounting, etc.

[0072] Step 002: Perform device welding.

[0073] like Figure 9bAs shown, the device 30 is fixed on the substrate 10 by LF (Leadframe) welding. The device 30 includes various active and passive devices, chips, isolated components or packaged chips, capacitors and other resistors and capacitors.

[0074] Step 003: interconnecting devices.

[0075] like Figure 9c As shown, the device 30 is connected to the circuit layer of the substrate 10 via a bonding wire 40. One end of the bonding wire 40 is electrically connected to the surface of the device 30 facing away from the substrate 10, and the other end is connected to the pad 20 on the substrate 10, thereby connecting the device 30 to the circuit. The device 30 is electrically connected to the circuit layer via the bonding wire 40.

[0076] Step 004: Assemble the pins.

[0077] like Figure 9d As shown, solder paste is applied to the pad 20 corresponding to the pin 50, and the pin 50 is fixed to the corresponding pad 20 by welding. The pin 50 is electrically connected to the circuit layer on the substrate 10 through the pad 20.

[0078] Step 005: Assemble the sealing layer.

[0079] like Figure 9e As shown, the sealing layer 60 is placed on the pin 50, and the sealing layer 60 and the pin 50 are sealed. The sealing method of the sealing layer 60 and the pin 50 can be referred to Figure 4 When the sealing layer 60 is placed on the pin 50, the insertion depth of the sealing layer 60 can be limited by the limiting structure of the pin 50, thereby limiting the thickness of the plastic layer 80 by the sealing layer 60 to avoid plastic sealing to the connection area of ​​the pin 50. For details, please refer to Figure 5 The relevant description in will not be repeated here.

[0080] Step 006: Assemble the cover.

[0081] like Figure 9f As shown, the cover plate 70 is mounted on the pin 50 and the cover plate 70 is stacked with the sealing layer 60. When setting, the boss structure of the sealing layer 60 is inserted into the receiving groove of the cover plate 70, thereby improving the sealing effect between the pin 50 and the sealing layer 60. For details, please refer to Figure 7 The relevant description in will not be repeated here.

[0082] Step 007: Module plastic sealing.

[0083] like Figure 9g As shown, Figure 9fThe semi-finished product prepared in the process is placed into a mold for injection molding, and the molding compound is heated and solidified to form a molding layer 80 .

[0084] The embodiment of the present application further provides a preparation mold, and the plastic packaging process of the power module is described in detail below in conjunction with the preparation mold.

[0085] Figure 10 A structural schematic diagram of a preparation mold provided in an embodiment of the present application is shown. The mold 100 provided in an embodiment of the present application is used to produce the above-mentioned power module. The preparation mold 100 includes an upper mold 110 and a lower mold 120 covering the upper mold 110. When in use, the lower mold 120 can be fixedly set on an equipment or a mold frame, and the upper mold 110 can be set on an equipment or a mold frame and can move relative to the lower mold 120, wherein the device that drives the upper mold 110 to move is a common device in injection molding equipment and will not be described in detail here. When the upper mold 110 is lifted to a certain height relative to the lower mold 120, the upper mold 110 is separated from the lower mold 120, and the semi-finished product 200 to be injected can be placed in the lower mold 120 and fixed. Afterwards, the upper mold 110 can be lowered to a certain height, covering the lower mold 120, and enclosing a space for injection molding.

[0086] Figure 11 The diagram shows the structure of the upper mold provided in an embodiment of the present application. The upper mold 110 used in the embodiment of the present application includes a fixed base 111 and an upper mold core 112 detachably connected to the fixed base 111. The fixed base 111 is used to connect to the device that drives the upper mold 110, while the upper mold core 112 is used to abut the semi-finished product 200 to be injected. When the upper mold 110 and the lower mold are closed, the upper mold core 112 presses against the lower mold to enclose a space filled with thermosetting material.

[0087] When the upper mold core 112 abuts the semi-finished product 20 to be molded, it abuts the cover plate and serves to define the position of the cover plate, ensuring that the molding compound is filled between the sealing layer and the base plate during injection molding. If the power module does not have a cover plate, the upper mold core 112 abuts the sealing layer to define its position, achieving the same effect.

[0088] As an optional solution, a cavity 1111 is provided in the fixing seat 111, and the cavity 1111 is used to accommodate the upper mold core 112. For example, the cavity 1111 can be a trapezoidal cavity, and its side walls are perpendicular to the vertical direction (in the direction of the cavity 1111). Figure 11 The upper mold core 112 is also shaped like a matching trapezoid. During assembly, the sidewalls of the cavity 1111 fit over the outer walls of the upper mold core 112, securing the upper mold core 112 within the mounting base 111. Alternatively, a removable fixed connection between the upper mold core 112 and the mounting base 111 can be employed, using screws (screws, bolts, or bolt assemblies).

[0089] The upper mold core 112 is provided with an avoiding hole 1121 for avoiding the pins. When the upper mold core 112 abuts against the cover plate or the sealing layer, the pins can pass through the avoiding hole 1121, and the upper mold core 112 is avoided from being extruded to the pins. As shown in Figure 11 The upper mold core 112 has a certain height in the vertical direction, so as to ensure that the depth of the avoiding hole 1121 is not less than the length of the connecting area of the pins, and the safety of the pins is improved.

[0090] As an optional solution, when the upper mold core 112 abuts against the cover plate, a positioning structure is arranged between the upper mold core 112 and the cover plate, so as to ensure that the upper mold core 112 can be aligned with the cover plate, and the precision during injection molding is improved. As an optional solution, the positioning structure can include a positioning column 1122 arranged on the upper mold core 112, and a positioning groove arranged on the cover plate and matched with the positioning column 1122. Alternatively, the positioning structure can include a positioning groove arranged on the upper mold core 112, and a positioning column arranged on the cover plate and matched with the positioning groove.

[0091] Referring to Figure 12 , Figure 12 The bottom view of the upper mold core is shown. The surface of the upper mold core 112 (the first surface 1123) towards the lower mold should have sufficient contact area with the cover plate or the sealing layer, and meanwhile all the pins can pass through the avoiding hole 1121. As an example, the corners of the first surface 1123 are not provided with the avoiding hole 1121, so as to ensure that the first surface 1123 can abut against the cover plate or the sealing layer, the edge of the cover plate or the sealing layer is avoided from being warped, and the injection molding effect of the power module is ensured.

[0092] As an optional solution, the avoiding hole 1121 can correspond to one pin, or the avoiding hole 1121 can correspond to at least two pins. When the avoiding hole 1121 corresponds to at least two pins, two or more pins which are relatively close on the power module can be divided into a group of pins. The avoiding hole 1121 arranged on the first surface 1123 can accommodate one pin or a group of pins, so that the number of the avoiding hole 1121 arranged can be reduced, and meanwhile the precision requirement of the mold is also reduced.

[0093] When the power module adopts different functions, the number and arrangement mode of the corresponding pins are also different, and therefore the preparation mold provided in the embodiments of the present application has upper mold cores corresponding to different types of power modules. Each upper mold core has avoiding holes matching the pins of the power module corresponding to the upper mold core. When production is needed to be changed, the upper mold core only needs to be taken down from the fixing seat for replacement, and the fixing seat in the lower mold and the upper mold does not need to be replaced, so that different types of power modules can be produced by one set of equipment, and the replacement is convenient.

[0094] As can be seen from the above description, the mold preparation provided in the embodiments of this application can achieve high-reliability production of plastic-encapsulated power modules. Furthermore, by replacing the replaceable upper mold core, the corresponding plastic-encapsulated mold can easily implement the process development of power modules with pins in different locations, reducing development costs and mold opening cycles, thereby improving product development efficiency. Furthermore, if a mold becomes unusable due to glue overflow due to a production anomaly, the problem can be quickly resolved by replacing the replaceable upper mold core, avoiding any impact on production.

[0095] The present application also provides a device comprising a power module and any of the aforementioned power modules connected to the power module. The device may be a servo motor, a frequency converter, an inverter, or other similar device. Regardless of the specific function of the device, the power module may be provided with a plastic encapsulation layer to encapsulate the pins, thereby enhancing the waterproof and moisture-proof properties of the power module, improving the protection of the power module, and improving the performance of the power module. This, in turn, improves the waterproof and moisture-proof properties of the device and enhances its safety.

[0096] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A power module, characterized in that: include: a substrate, on which a device is disposed, and the device is electrically connected to the substrate; a sealing layer, spaced apart from the substrate, with a filling space between the substrate and the sealing layer; A plastic encapsulation layer, filling the filling space between the substrate and the sealing layer, and encapsulating the device; wherein the plastic encapsulation layer is a plastic encapsulation layer made of a thermosetting material; A pin is inserted through the sealing layer and the plastic sealing layer and is electrically connected to the substrate, wherein a portion of the pin is exposed on a side of the sealing layer away from the plastic sealing layer; The power module further includes a cover plate, the cover plate covering the sealing layer and being bonded to the sealing layer by adhesive; the hardness of the cover plate is greater than the hardness of the sealing layer; the pins pass through the cover plate and are exposed on a side of the cover plate away from the plastic sealing layer; The plastic encapsulation layer is extended outside the sealing layer, and the extended portion of the plastic encapsulation layer wraps the edge sidewall of the substrate, the edge sidewall of the sealing layer, and the edge sidewall of the cover plate, and the extended portion of the plastic encapsulation layer forms a frame structure; A boss structure corresponding to each pin is provided on one side of the sealing layer away from the plastic sealing layer, and each pin passes through the corresponding boss structure. The cover plate is provided with a receiving groove that cooperates with the boss structure, and the boss structure is interference fit with the receiving groove.

2. The power module according to claim 1, wherein: Each pin has a limiting structure, and a side of the sealing layer facing the plastic sealing layer is pressed against the limiting structure.

3. The power module according to claim 2, wherein: The limiting structure is a step structure.

4. The power module according to any one of claims 1 to 3, wherein: The plastic sealing layer is a plastic sealing layer prepared by EMC plastic sealing material.

5. A mold preparation method, characterized in that: Used to prepare the power module according to any one of claims 1 to 4; the preparation mold includes a lower mold and an upper mold covering the lower mold; wherein the upper mold includes a fixing seat and an upper mold core detachably connected to the fixing seat; The upper mold core is provided with an avoidance hole for avoiding the insertion pin; when the upper mold and the lower mold are covered, the upper mold core and the lower mold are pressed and contacted, and form a space filled with thermosetting material; the upper mold core is provided with a positioning column, and the cover plate is provided with a positioning groove that cooperates with the positioning column.

6. A device, characterized in that The invention comprises a power module and a power module according to any one of claims 1 to 4 connected to the power module.

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