Intelligent Power Module and Manufacturing Method Thereof

Abstract

The present invention relates to an intelligent power module and a manufacturing method thereof. By providing a boss on a circuit board and providing a specific potential part at a position near the boss in a circuit wiring layer, the IPM module can selectively electrically connect or disconnect the boss and the specific potential part through a metal connector in the later stage of manufacturing, thereby forming a structure in which the circuit board of the IPM module is grounded or not grounded. In this way, it is not necessary to manufacture two different IPM modules for the grounding or non-grounding of the circuit board. Only one structure of the IPM module needs to be manufactured, thereby reducing the manufacturing cost. Moreover, for the case where the circuit board is grounded, there is no need to use a drilling process, thereby avoiding the problem of reliable connection of metal connection wires caused by this process, and thus also improving the manufacturing yield.

Description

Technical Field

[0001] The present invention relates to an intelligent power module and a manufacturing method thereof, belonging to the technical field of power semiconductor devices. Background Art

[0002] In general, an IPM (Intelligent Power Module) operates at a switching frequency of 10 - 40 kHz. Experiments show that for a working frequency of 10 - 20 kHz, if the circuit board of the IPM module is connected to the ground, the probability of mis-triggering of the IPM module during the process is lower; while for a working frequency of 20 - 40 kHz, if the circuit board of the IPM module is connected to the ground, the probability of mis-triggering of the IPM module during the process is higher. Therefore, for different working frequency environments of IPM module applications, it is necessary to manufacture whether the circuit board is grounded, that is, two IPM modules with different internal structures are manufactured accordingly, which will increase the manufacturing cost. In addition, when manufacturing an IPM module whose circuit board needs to be grounded, it is generally achieved through a drilling process for the ground potential. The control of the drilling position and the flatness of the hole bottom in this process is very difficult. Poor drilling position and flatness of the hole bottom will directly affect the reliability of the metal connection wires, leading to problems such as wire breakage, resulting in IPM scrapping, low yield in the manufacturing process, and pushing up the manufacturing cost. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to solve the problems of increased manufacturing cost due to unstable manufacturing processes in the process of designing and manufacturing two types of IPM modules with grounded and ungrounded circuit boards, and the risk problems in the use process caused by material mixing due to the same appearance of the subsequent finished products.

[0004] Specifically, the present invention discloses an intelligent power module, including:

[0005] A circuit board made of a metal material;

[0006] An insulating layer, which is arranged on the surface of the circuit board;

[0007] A circuit wiring layer, which is arranged on the insulating layer;

[0008] Circuit elements, which are arranged on the circuit wiring layer;

[0009] Multiple pins, which are arranged at least on one side edge of the circuit board, and the pins are electrically connected to the circuit wiring layer;

[0010] A sealing layer, which at least wraps one surface of the substrate where the circuit elements are arranged, and one end of the pin exposes from the sealing layer;

[0011] On the upper surface of the circuit board, there are also bosses formed for electrical connection with the circuit board. On the circuit wiring layer, there is a specific ground potential part that can be electrically connected to the bosses, and the bosses and the specific ground potential part are arranged close to each other.

[0012] Optionally, the bosses protrude from the surface of the insulating layer, and the bosses are integrally formed with the circuit board; and the height error between the bosses and the height of the circuit wiring layer is -0.6 mm to +0.6 mm; the distance between the bosses and the specific ground potential part is 0.5 mm to 2 mm.

[0013] Optionally, the sealing layer is also respectively provided with fine holes corresponding to the bosses and the specific ground potential part, so that the bosses and the specific ground potential part are exposed outward from the fine holes.

[0014] Optionally, the surface of the bosses is coated with solder paste or silver paste; the specific ground potential part is electrically connected to the ground pin of the intelligent power module or the reserved empty pin.

[0015] Optionally, the sealing layer is also respectively provided with fine holes corresponding to the bosses and the specific ground potential part, so that the bosses and the specific ground potential part are exposed outward from the fine holes.

[0016] Optionally, the intelligent power module further includes a metal connector. The metal connector includes two bent feet formed by bending both ends toward the same side and a connecting body connecting the bent feet. The foot diameters of the two bent feet are adapted to the sizes of the fine holes. The two bent feet of the metal connector extend into the fine holes to be respectively electrically connected to the bosses and the specific ground potential part, and the connecting body is installed on the surface of the sealing layer.

[0017] Optionally, the sealing layer is also provided with a groove between the two fine holes. The width of the connecting body is adapted to the width of the groove, and the connecting body is installed in the groove.

[0018] Optionally, the end face of one end of the bent foot is a plane, and the width of the connecting body is greater than the foot diameter of the bent foot.

[0019] Optionally, sealant is provided in the remaining space for installing the metal connector in the two fine holes and the groove.

[0020] The present invention also discloses a manufacturing method of the intelligent power module according to the above, including the following steps:

[0021] Providing bosses on the surface of the circuit board made of metal material;

[0022] Providing an insulating layer on the surface of the circuit board except for the bosses, and forming a circuit wiring layer on the surface of the insulating layer;

[0023] Arranging circuit elements and pins at corresponding positions on the circuit wiring layer;

[0024] Connecting metal wires between multiple circuit elements or between a circuit element and a pin;

[0025] The circuit board provided with circuit components and pins is injection molded through a packaging mold to form a sealing layer, where the sealing layer covers at least one side of the circuit board where the circuit components are provided; the upper film and the lower film are arranged up and down on the packaging mold, the pins are fixedly arranged between the upper film and the lower film, the free ends of at least two ejector pins arranged on the upper film respectively abut against the surface of the boss and the specific ground potential part of the circuit wiring layer, the pins protrude from the sealing layer, and after demolding, two corresponding small holes are formed in the sealing layer at the positions where the ejector pins abut against the boss and the specific ground potential part;

[0026] The pins are cut and formed to form an intelligent power module, and the formed intelligent power module is tested.

[0027] Optionally, arranging the boss on the surface of the circuit board made of metal material includes:

[0028] The boss is formed at the edge position of the circuit board by at least one of laser etching, mechanical pressure and flat-bottomed turning head grinding.

[0029] Optionally, the manufacturing method further includes:

[0030] Manufacturing a metal connector, where the metal connector includes two bending feet bent toward the same side at both ends to form two bending feet, and a connecting body connecting the bending feet;

[0031] The metal connector is installed in the installation position formed by the small holes and the grooves, where the two bending feet respectively penetrate into the small holes and abut against the boss and the specific ground potential part to form an electrical connection, and the connecting body is installed on the surface of the sealing layer.

[0032] Optionally, after the circuit board with circuit components and pins is injection molded through a packaging mold to form a sealing layer, the manufacturing method further includes:

[0033] A groove is arranged between the two small holes so that the connecting body is installed in the groove.

[0034] Optionally, the manufacturing method further includes:

[0035] Sealing glue is injected into the remaining space of the two small holes.

[0036] The intelligent power module of the present invention sets a boss on the circuit board and sets a specific ground potential part at a position of the circuit wiring layer close to the boss, so that the IPM module can selectively electrically connect or not connect the boss and the specific ground potential part through a metal connector in the later stage of manufacturing, thereby forming a structure in which the circuit board of the IPM module is grounded or not grounded. In this way, it is not necessary to manufacture two different IPM modules for the grounding or non-grounding of the circuit board, and only one structure of the IPM module needs to be manufactured, thus reducing the manufacturing cost. Moreover, for the case where the circuit board is grounded, there is no need to adopt a drilling process, thereby avoiding the problem of reliable connection of the metal connecting wire caused by this process, and thus also improving the manufacturing yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is an external view of the IPM module according to an embodiment of the present invention;

[0038] Figure 2 is Figure 1 a cross-sectional view taken along the X-X' direction in

[0039] Figure 3 is a top view of the IPM module according to an embodiment of the present invention after removing the sealing layer;

[0040] Figure 4 is a process diagram of manufacturing an insulating layer and a circuit wiring layer on a circuit board with a boss during the manufacturing process of the IPM module according to an embodiment of the present invention;

[0041] Figure 5 is Figure 4 a cross-sectional view taken along the Y-Y direction in

[0042] FIG. 6(A) and FIG. 6(B) are schematic diagrams of the pin structure of the IPM module according to an embodiment of the present invention;

[0043] Figure 7 is a schematic diagram of the structure of the metal connector of the IPM module according to an embodiment of the present invention;

[0044] Figure 8 is during the manufacturing process of the IPM module according to an embodiment of the present invention on Figure 4 the basis of installing pins and circuit elements;

[0045] Figure 9 is Figure 8 a side view of;

[0046] Figure 10 is during the manufacturing process of the IPM module according to an embodiment of the present invention on Figure 8 the basis of installing metal wires;

[0047] Figure 11 is Figure 10Side view;

[0048] Figure 12 In the manufacturing process of the IPM module according to an embodiment of the present invention, Figure 10 Based on this, it is a process diagram of injection molding to form a sealing layer;

[0049] Figure 13 It is a schematic structural diagram of the sealing layer of the IPM module according to an embodiment of the present invention, showing two fine holes exposed;

[0050] Figure 14 It is a schematic structural diagram of the IPM module according to an embodiment of the present invention after installing a metal connector on the sealing layer;

[0051] Figure 15 It is a flowchart of the manufacturing steps of the IPM module according to an embodiment of the present invention.

[0052] Reference numerals:

[0053] IPM module 10, pin 11, sealing layer 12, fine hole 12A, groove 12B, circuit element 14, metal wire 15, circuit board 16, insulating layer 17, circuit wiring layer 18, pad 18A, boss 18B, metal connector 18C, connection body 18C1, bent leg 18C2, specific potential part 18D, carrier 20, upper mold 44, lower mold 45, fixing device 46, ejector pin 47, gate 53, exhaust port 54. Detailed implementation manners

[0054] It should be noted that, without conflict in structure or function, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to examples.

[0055] The present invention provides an intelligent power module. As Figures 1 to 3As shown in the figure, the IPM module 10 according to an embodiment of the present invention includes a circuit board 16, an insulating layer 17, a circuit wiring layer 18, a plurality of circuit elements 14, a plurality of pins 11, and a sealing layer 12. The circuit board 16 is made of a metal material, such as a rectangular plate made of aluminum with materials such as 1100 and 5052. Its thickness is much larger than that of other layers, generally 0.8 mm to 2 mm, and a commonly used thickness is 1.5 mm, mainly realizing heat conduction and heat dissipation functions. The insulating layer 17 is disposed on the surface of the circuit board 16, and its thickness is relatively thinner than that of the circuit board 16, generally 50 μm to 150 μm, and a commonly used one is 110 μm. The circuit wiring layer 18 is composed of a metal such as copper and is insulated from the circuit board 16. The circuit wiring layer 18 includes circuit lines formed by etched copper foils, and the thickness of the line layer is also relatively thin, such as about 70 μm. The circuit wiring layer 18 also includes pads 18A disposed at the side position close to the circuit board 16, and the above-mentioned circuit wiring layer 18 can be formed by using 2-ounce copper foil. Finally, a relatively thin solder mask layer can be coated on the circuit wiring layer 18 to play a role in line isolation and cut off the electrical connection between circuit lines. A plurality of circuit elements 14 are disposed on the circuit wiring layer 18, and the plurality of circuit elements 14 or between the circuit elements 14 and the circuit wiring layer 18 can be electrically connected by metal wires; the circuit elements 14 can be fixed to the circuit wiring layer 18 by welding. A plurality of pins 11 are disposed at at least one side edge of the circuit board 16, and the pins 11 are electrically connected to the wiring layer; the plurality of pins 11 form a lead frame and are welded to the pads of the circuit wiring layer 18 by welding such as solder paste welding, so as to realize electrical connection with the circuit wiring layer 18. The sealing layer 12 at least wraps and disposes one surface of the circuit board 16 where the circuit elements 14 are located, and one end of the pin 11 protrudes from the sealing layer 12; the sealing layer 12 is mainly formed by an injection molding material, and its material can be a resin.

[0056] On the surface of the circuit board 16 where the insulating layer 17 is disposed, there is also a boss 18B disposed. The boss 18B is electrically connected to the circuit board 16. On the circuit wiring layer 18, there is a specific ground potential portion 18D that can be electrically connected to the boss 18B, and the boss 18B and the specific ground potential portion 18D are disposed close to each other. The specific ground potential portion 18D here can be a ground point on the circuit wiring layer 18, such as a small-area copper foil region connected to a pin 11 for grounding. The pin 11 for grounding here can be a ground pin of the IPM module or a reserved empty pin. When the IPM module is installed on the circuit board, it needs to be connected to the ground line of the circuit board, and the setting of the empty pin can be specifically determined according to whether the circuit board 16 of the IPM module needs to be grounded. If the circuit board 16 needs to be grounded, the empty pin needs to be reserved and connected to the ground wire on the circuit board. If the circuit board 16 does not need to be grounded, the empty pin does not need to be reserved, that is, it can be cut off before the IPM module is installed on the circuit board, so there is no need to be welded to the circuit board.

[0057] For the IPM module 10 of the present invention, by providing a boss 18B on the circuit board 16 and providing a specific ground potential portion 18D at a position of the circuit wiring layer 18 close to the boss 18B, the IPM module 10 can selectively electrically connect or disconnect the boss 18B and the specific ground potential portion 18D through a metal connector in the later stage of manufacturing, so as to form a structure in which the circuit board 16 of the IPM module 10 is grounded or not grounded. In this way, it is not necessary to manufacture two different IPM modules 10 for grounding or not grounding the circuit board 16, and only one structure of the IPM module 10 needs to be manufactured, thereby reducing the manufacturing cost. Moreover, for the case where the circuit board 16 is grounded, there is no need to adopt a drilling process, thereby avoiding the problem of reliable connection of the metal connection wires caused by this process, and thus also improving the manufacturing yield.

[0058] In some embodiments of the present invention, the boss 18B protrudes from the surface of the insulating layer 17, and the boss 18B is integrally formed with the circuit board 16. As Figure 2 shown, in order to facilitate the electrical connection with the specific ground potential portion 18D of the circuit wiring layer 18, their heights are set to be approximately the same, so that the boss 18B protrudes from the surface of the insulating layer 17. Preferably, the height error between the boss 18B and the circuit wiring layer 18 is from -0.6 mm to +0.6 mm, and values such as -0.5 mm, -0.3 mm, -0.1 mm, 0 mm, 0.1 mm, 0.3 mm, 0.5 mm can be set as the height error values. In order to facilitate the connection between the boss 18B and the specific ground potential portion 18D, the distance therebetween is set to be from 0.5 mm to 2 mm, and values such as 0.5 mm, 1 mm, 1.5 mm, and 2 mm can be set, so as not to be too close or too far to affect their connection.

[0059] In some embodiments of the present invention, the surface of the boss 18B is coated with solder paste or silver paste. This can enhance the electrical connection ability when the metal connector contacts the boss 18B, so that the boss 18B can form a good electrical connection with the specific ground potential portion 18D.

[0060] In some embodiments of the present invention, the resin forming the sealing layer 12 can be molded using a thermosetting resin by a transfer molding method or a thermoplastic resin by an injection molding method. The sealing layer 12 is also provided with micropores 12A at the corresponding boss 18B and the specific ground potential portion 18D respectively, so that the boss 18B and the specific ground potential portion 18D are exposed outward from the micropores 12A. At this time, the resin completely seals all positions on one side of the circuit wiring layer 18 of the circuit board 16 except for the boss 18B and the specific ground potential portion 18D. The aperture of the micropores 12A here can be set between 0.5 mm and 1 mm, so that through these two micropores 12A, a metal connecting component can penetrate deep into the middle of these two micropores 12A to electrically connect the boss 18B and the specific ground potential portion 18D, thereby grounding the circuit board 16; for the case where the circuit board 16 does not need to be grounded, these two micropores 12A can be retained. Since the apertures of these two micropores 12A are very small, they will not affect the airtightness and watertightness of components such as the circuit elements 14 and the circuit wiring layer 18 on the circuit board 16 of the IPM module. Of course, in order to further improve the airtightness and watertightness, for the case where the circuit board 16 does not need to be grounded, these two micropores 12A can be further filled with a hole-sealing adhesive to further improve the airtightness and watertightness.

[0061] In some embodiments of the present invention, such as Figure 2As shown, it further includes a metal connector 18C. The metal connector 18C includes two bent feet 18C2 formed by bending both ends towards the same side, and a connecting body 18C1 connecting the bent feet. The diameters of the two bent feet 18C2 are adapted to the sizes of the two small holes 12A. The two bent feet 18C2 of the metal connector 18C extend into the two small holes 12A to be electrically connected to the boss 18B and the specific potential part 18D respectively, and the connecting body 18C1 is installed on the surface of the sealing layer 12. For the IPM module with the circuit board 16 grounded, the metal connector is the metal connector 18C, which plays the role of connecting the boss 18B and the specific potential part 18D. The diameter of the bent foot 18C2 is slightly smaller than or basically the same as the cross-sectional area of the boss 18B, so that one end of the bent foot 18C2 can be in full contact with the surface of the boss 18B to form a good electrical connection. By setting the metal connector 18C with a bent shape at both ends, in the later manufacturing stage after the sealing layer 12 is formed on the IPM module, the two bent feet of the metal connector 18C can be conveniently inserted into the small holes 12A to contact the boss 18B and the specific potential part 18D. The small holes 12A play a guiding role during the installation of the metal connector 18C, thus facilitating the installation of the metal connector 18C and improving the installation efficiency. By setting the aperture size of the small holes 12A to be adapted to the diameter of the bent feet 18C2, the wall surface of the small holes 12A can be in relatively close contact with the bent feet 18C2. In this way, the small holes 12A also play a role in fixing the bent feet 18C2, so that the bent feet 18C2 can be firmly stuck in the small holes 12A without relative movement, thereby ensuring the stability of the good electrical contact between one end of the two bent feet 18C2 and the boss 18B and the specific potential part 18D respectively. And by the connecting body 18C1 being exposed outward in the sealing layer 12, it is convenient to distinguish the structures of the two circuit boards 16 of the IPM module with and without grounding from the appearance, thus avoiding the mixing risk caused by the fact that the grounding and non-grounding are completely the same in appearance in the prior art, which ultimately leads to serious problems such as control disorder caused by mis-triggering during the operation of the IPM module, or burning of the IPM module body or the electrical appliance where the IPM module is located.

[0062] Furthermore, the sealing layer 12 is also provided with a groove 12B between two fine holes 12A, wherein the width of the connecting body 18C1 is adapted to the width of the groove 12B. When the metal connector 18C is installed, the connecting body 18C1 can be installed in the groove 12B, so that the connecting body 18C1 can be installed in the groove 12B and the connecting body 18C1 does not protrude from the surface of the sealing layer 12. This avoids the problem of unreliable circuit board 16 base caused by the loosening of the metal connector 18C due to the exposure of the connecting body 18C1 and the easy contact of the surface of the sealing layer 12 with foreign objects during the use of the IPM module value, resulting in the inability of its two bent legs 18C2 to form a good electrical connection with the boss 18B and the specific potential part 18D.

[0063] In some embodiments of the present invention, the end face of one end of the bent leg 18C2 is a plane, so that the contact surface between the bent leg 18C2 and the boss 18B and the specific potential part 18D is increased, forming a good electrical connection. The width of the connecting body 18C1 is greater than the diameter of the bent leg 18C2. This makes it convenient to clamp and install the connecting body 18C1, which helps to improve the installation efficiency.

[0064] In some embodiments of the present invention, sealant is provided in the remaining space for installing the metal connector 18C in the two fine holes 12A and the groove 12B. This can further strengthen the reliable fixation of the metal connector 18C, and at the same time further improve the airtightness and watertightness of the IPM module.

[0065] In some embodiments of the present invention, specifically, the circuit element 14 adopts active elements such as transistors or diodes, or passive elements such as capacitors or resistors. In addition, elements with a large amount of heat generation such as power elements can be fixed on the circuit board 16 through a heat sink made of copper or the like. Here, the active elements mounted face up are connected to the circuit wiring 18 through the metal wire 15. The insulating layer 17 is formed to cover at least one surface of the circuit board 16. And fillers such as alumina and aluminum silicon carbide can be filled in the resin material such as epoxy resin forming the sealing layer 12 at a high concentration to improve the thermal conductivity. In order to improve the thermal conductivity, the fillers can be in an angular shape. In order to avoid the risk of the fillers damaging the surface of the circuit element 14, the fillers can be in a spherical shape. The pins 11 are generally made of metals such as copper, and a nickel-tin alloy layer is formed on the copper surface through electroless plating and electroplating. The thickness of the alloy layer is generally 5 μm, and the plating layer can protect the copper from corrosion and oxidation and can improve the weldability.

[0066] The present invention also provides a manufacturing method of the IPM module mentioned in the above embodiments, as Figure 15 shown, the manufacturing method includes the following steps:

[0067] Step S100, providing a boss on the surface of a circuit board made of a metal material;

[0068] Step S200: Set an insulating layer on the surface of the circuit board except for the boss, and form a circuit wiring layer on the surface of the insulating layer;

[0069] Step S300: Arrange circuit components and pins at corresponding positions on the circuit wiring layer;

[0070] Step S400: Connect metal wires between multiple circuit components or between a circuit component and a pin;

[0071] Step S500: Inject the substrate with circuit components and pins through a packaging mold to form a sealing layer. The sealing layer covers at least one side of the circuit board where the circuit components are arranged. The packaging mold has an upper film and a lower film arranged up and down. The pins are fixedly arranged between the upper film and the lower film. The free ends of at least two ejector pins arranged on the upper film abut against the surface of the boss and a specific ground potential part of the circuit wiring layer. The pins protrude from the sealing layer. After demolding, two corresponding small holes are formed in the sealing layer at the positions where the ejector pins abut against the boss and the specific ground potential part;

[0072] Step S600: Cut and shape the pins to form an IPM module, and test the formed IPM module.

[0073] The manufacturing method of the IPM module 10 includes multiple processes, which may specifically include Process 1 of setting an insulating layer 17 on the surface of the circuit board 16 with a boss 18B; Process 2 of forming a circuit wiring 18 and a pad 18A on the surface of the insulating layer 17; Process 3 of manufacturing plated pins 11 and a boss 18C; Process 4 of connecting a circuit component 14 to the circuit wiring 18 and connecting a pin 11 to the pad 18A; Process 5 of cleaning; Process 6 of connecting the circuit component 14 and the circuit wiring 16 with a metal wire 15; Process 7 of baking and molding; Process 8 of cutting and shaping the pins 11; Process 9 of assembling for functional and appearance testing. The above manufacturing method steps are respectively included in these processes.

[0074] In step S100, corresponding to Process 1, refer to Figure 4 , design a circuit board 16 with a suitable size according to the required circuit layout. For a general IPM module 10, the size of one piece can be selected as 64 mm × 30 mm. Taking the circuit board 16 as an aluminum substrate as an example, the aluminum substrate is formed by directly routing a 1 m × 1 m aluminum material. The routing tool uses high-speed steel as the material, the motor uses a rotational speed of 5000 revolutions per minute, and the routing tool cuts at a right angle to the plane of the aluminum material; it can also be formed by stamping. Then, through methods such as etching and stamping, a boss 18B can be formed at the edge position of the circuit board 16. The specific method of the boss 18B can be laser etching, mechanical pressure, or flat-bottomed drill bit grinding.

[0075] Then, corrosion prevention treatment can be performed on both sides of the circuit board 16. For the IPM module 10 with a semi-encapsulation structure, the side of the circuit board 16 without circuit components is exposed from the sealing layer 12. At this time, corrosion prevention enhances its corrosion resistance during use and is not easily oxidized. For the IPM module 10 with a full-encapsulation structure, in order to save costs, corrosion prevention treatment may not be performed either.

[0076] In step S200, corresponding to process two, refer to Figure 5 An insulating layer 17 is provided on the side of the circuit board 16 having the boss 18B, where the boss 18B protrudes above the height of the insulating layer 17. Then, a copper foil is laminated on the surface of the insulating layer 17, and then the copper foil is etched to locally remove the copper foil to form a circuit wiring layer 18, where the circuit wiring layer 18 includes circuit lines and also includes pads 18A provided at the side positions close to the circuit board.

[0077] In step S300, this step includes process three and process four, where process three is the process of manufacturing the pins 11. The manufacturing process of the pins 11 is as follows: All the pins 11 are made of a metal substrate such as a copper substrate, such as a long strip with a length C of 25 mm, a width K of 1.5 mm, and a thickness H of 1 mm, as Figure 6A shown. For ease of assembly, a certain arc can be pressed and shaped at one end, as Figure 6B shown; then, a nickel layer is formed on the surface of the pins 11 by electroless plating: By a mixed solution of nickel salt and sodium hypophosphite, and adding an appropriate complexing agent, a nickel layer is formed on the surface of the copper material with a specific shape. Nickel has a strong passivation ability and can quickly form a very thin passivation film, which can resist the corrosion of the atmosphere, alkali, and certain acids. The nickel plating crystals are extremely fine, and the thickness of the nickel layer is generally 0.1 μm; then, through an acidic sulfate process, the copper material with the formed shape and nickel layer is immersed in a plating solution with positive tin ions at room temperature and energized to form a nickel-tin alloy layer on the surface of the nickel layer. The thickness of the nickel layer is generally controlled at 5 μm, and the formation of the nickel layer greatly improves the protection and solderability. Thus, the pins 11 are manufactured.

[0078] In process four, first, a solder paste printer is used with a stencil to apply solder paste to specific positions of the circuit wiring 18 on the circuit board 16. The stencil can have a thickness of 0.13 mm, and these specific positions are where solder paste welding is required, such as welding circuit components 14, etc. at these specific positions subsequently. Or a silver paste dispenser is used to apply a specific pattern with silver paste at specific positions, and the circuit components 14 can also be welded at these specific positions through the silver paste.

[0079] Then refer to Figure 8 and Figure 9As shown, the circuit component 14 and the pin 11 are installed. The circuit component 14 can be directly placed at the above-mentioned specific position of the circuit wiring 18. One end of the pin 11 should be placed on the pad 18A, and the other end needs to be fixed by the carrier 20. The carrier 20 is made of materials such as composite stone and stainless steel to fix the pin 11 at the position of the pad 18A. Then, the circuit board 16 placed on the carrier 20 is subjected to reflow soldering, and the solder paste or silver paste is cured. The circuit component 14 and the pin 11 are respectively soldered and fixed at the specific position and the pad 18A.

[0080] In step S400, for process six, as Figure 10 and Figure 11 shown, an electrical connection is formed by bonding a metal wire 15 with a certain diameter at specific positions of the circuit component 14 and the circuit wiring 18. Here, the thickness of the metal wire 15 should be determined by comprehensively considering factors such as the size of the bonding point, the required current-carrying capacity, and the processability of the components. Generally, the diameter of a single metal wire should not be greater than 400 μm and should not be less than 15 μm. For the connection of the circuit component 14 as a power device, multiple 400-μm aluminum wires can be considered for parallel bonding or an aluminum busbar can be used for bonding. For the connection of functional devices, a single 38-μm aluminum wire can be considered for bonding.

[0081] Furthermore, in this step, before process six, process five of cleaning the circuit board 16 can also be included. In process five, first, the circuit board 16 is placed in a cleaning machine for cleaning to wash away the residual flux such as rosin during reflow soldering and foreign matters such as aluminum wires remaining during stamping. According to the layout density of the circuit component 14 on the circuit wiring 18, the cleaning can be carried out in the form of spraying, ultrasonic, or a combination of both. During cleaning, the circuit board 16 is placed in the cleaning tank by clamping two or more pins 11 with a robotic arm; the cleaning method can be spraying or ultrasonic. If there are devices with a thickness of 60 - 70 μm in the circuit component 14, the energy of spraying or ultrasonic should not be too high.

[0082] In step S500, for process seven, as Figure 12As shown, first, the circuit board 106 is baked in an oxygen-free environment. The baking time should not be less than 2 hours, and the baking temperature is selected to be 125°C. The circuit board 16 with pins 11 configured is transported to the encapsulation mold. The encapsulation mold includes an upper film 44 and a lower film 45 arranged up and down. The pins 11 are fixedly arranged between the upper film 44 and the lower film 45. The pins 11 fixed to the circuit board 16 by soldering contact the fixing device 46 located on the lower mold 45 to position the circuit board 16. At least two ejector pins 47 are provided on the upper mold 44. Taking two ejector pins 47 as an example, the free ends of the two ejector pins 47 abut against the surface of the boss 18B and the specific ground potential part 18D of the circuit wiring layer 18. Through these two ejector pins 47, on the one hand, it can be used to control the distance between the circuit board 16 and the lower mold 45. This distance cannot be too far, otherwise it will affect the heat dissipation, and this distance cannot be too close, otherwise it will cause problems such as incomplete injection of the encapsulant. The diameter of the ejector pin 47 is preferably designed to be 0.1 mm larger than the diameter of the contact point of the metal connector 18C.

[0083] Then, the encapsulation mold with the circuit board 16 placed in it is closed, and the sealing resin 12 is injected through the gate 53. The method of sealing can adopt transfer molding using a thermosetting resin or injection molding using a thermosetting resin. Moreover, the gas inside the cavity corresponding to the sealing resin 12 injected from the gate 53 is discharged to the outside through the vent 54.

[0084] Specifically for Figure 12 the shown encapsulation mold, where the widths of the injection runners on the upper and lower surfaces are inconsistent. Generally, the width of the runner on the upper surface is much larger than that on the lower surface. For the manufactured IPM module 1010, the injection pressure should be designed to be relatively large to avoid incomplete injection on the lower surface. For the semi-sealed design exposed on the lower surface, the injection pressure can be designed to be relatively small to avoid the risk of wire breakage caused by excessive injection pressure.

[0085] Finally, demolding is performed. After demolding, the sealing resin forms a sealing layer 12. The free ends of the pins 11 protrude from the sealing layer 12, and two small holes 12A are left at the installation positions of the ejector pins 47 on the sealing layer 12, so that the boss 18B and the specific ground potential part 18D of the circuit wiring 18 are exposed from the surface of the sealing layer 12 inward.

[0086] Through these two small holes 12A, according to the grounding requirement of the circuit board 16, it is convenient to install a metal connector into the small holes 18 to electrically connect the boss 18B and the specific ground potential part 18D. If there is no grounding requirement, the status quo can be maintained without installing a metal connector.

[0087] In step S600, for process eight and process nine. In process eight, according to the required length and shape, the shaping of pin 11 is carried out. After forming the sealing layer on the circuit board 16 through the encapsulation mold and demolding in the previous process seven, the initial version of the IPM module 10 as shown in Figure 13 can be formed. Two small holes 12A are formed on the surface of the sealing layer, and the bottoms of these two small holes 12A expose the boss 18B and the specific potential part 18D. Since the apertures of these two small holes 12A are very small, generally between 0.5 mm and 1 mm, even when the metal connector 18C is not assembled, the small holes 12A do not affect the airtightness and watertightness of the entire IPM module 10.

[0088] Then, the IPM module 10 is placed in a test device for routine electrical parameter tests, generally including test items such as insulation withstand voltage, static power consumption, and delay time, and then an appearance AOI test is carried out, generally including test items such as assembly hole size and pin offset. Those that pass the test are finished products. In this way, the manufacturing process of the entire IPM module 10 is completed.

[0089] In the manufacturing method of the IPM module 10 of the present invention, a boss 18B connected to the circuit board 16 is provided by protruding an insulating layer on the circuit board 16, and when the circuit board 16 is injection-molded with an encapsulation mold to form the sealing layer 12, at least two ejector pins 47 are provided on the upper surface of the encapsulation mold to respectively abut against the boss 18B and the specific potential part 18D of the circuit board 16, so that two small holes 12A are formed at the ejector pin 47 demolding contact positions of the sealing layer 12 during demolding, so that according to the grounding requirement of the circuit board 16, it is convenient to install a metal connector into the small holes 12A to electrically connect the boss 18B and the specific potential part 18D. If there is no grounding requirement, the status quo can be maintained without installing a metal connector. Thus, it is convenient to form the structure of grounding or not grounding the circuit board 16 of the IPM module 10. In this way, there is no need to manufacture two different IPM modules 10 for grounding or not grounding the circuit board 16, and only one structure of the IPM module 10 needs to be manufactured, thereby reducing the manufacturing cost. Moreover, for the case where the circuit board 16 is grounded, there is no need to adopt a drilling process, thus avoiding the problem of reliable connection of the metal connecting wire caused by this process, and thus also improving the manufacturing yield.

[0090] In some embodiments of the present invention, the manufacturing method further includes:

[0091] Step S700, manufacturing a metal connector, where the metal connector includes two bending feet bent towards the same side at both ends and a connecting body connecting the bending feet;

[0092] Step S800: Install the metal connector at the installation position formed by the fine holes and the groove 12B, where the two bent legs respectively penetrate into the fine holes and abut against the boss and the specific potential part to form an electrical connection, and the connection body is installed on the surface of the sealing layer.

[0093] As Figure 14 shown, for the case where the circuit board 16 of the IPM module 10 needs to be grounded, this embodiment adds a metal connector component, namely the metal connector 18C, to realize the electrical connection between the boss and the specific potential part 18D. To cooperate with the installation requirements of the fine holes 12A of the sealing layer 12, the metal connector 18C is set to be bent towards the same side, thereby forming two bent legs 18C2 and a connection body 18C1 connecting the two bent legs 18C2. The diameters of the two bent legs 18C2 are adapted to the sizes of the two fine holes 12A. Specifically, the diameter of the bent leg 18C2 is slightly smaller than or basically the same as the cross-sectional area of the boss 18B, so that one end of the bent leg 18C2 can completely contact the surface of the boss 18B to form a good electrical connection. By setting the metal connector 18C with a bent shape at both ends, the two bent legs 18C2 of the metal connector 18C can be conveniently inserted into the fine holes 12A to contact the boss 18B and the specific potential part 18D. The fine holes 12A play a guiding role during the installation of the metal connector 18C, thus facilitating the installation of the metal connector 18C and improving the installation efficiency. By setting the aperture size of the fine holes 12A to be adapted to the diameter of the bent legs 18C2, a relatively tight contact can be made between the wall surface of the fine holes 12A and the bent legs 18C2. In this way, the fine holes 12A also play a role in fixing the bent legs 18C2, so that the bent legs 18C2 can be firmly stuck in the fine holes 12A without relative movement, thereby ensuring the stability of the good electrical contact between one end of the two bent legs 18C2 and the boss 18B and the specific potential part 18D respectively. After the metal connector 18C is installed, the connection body 18C1 is located on the sealing surface, so that the grounded and ungrounded structures of the two circuit boards 16 of the IPM module 10 can be conveniently distinguished from the appearance, thus avoiding the mixing risk caused by the fact that the grounded and ungrounded states are exactly the same in appearance in the prior art, which ultimately leads to serious problems such as control disorders caused by mis-triggering during the operation of the IPM module 10, burning of the IPM module 10 itself, or burning of the electrical appliance where the IPM module 10 is located.

[0094] Further, in some embodiments of the present invention, after the substrate with the circuit element 14 and pins is injection molded through a packaging mold to form the sealing layer 12, the manufacturing method further includes: providing a groove 12B between two fine holes 12A. The width of the connection body 18C118C1 is adapted to the width of the groove 12B. When the metal connector 18C is installed, the connection body 18C118C1 can be installed in the groove 12B, so that the connection body 18C118C1 can be installed into the groove 12B without protruding from the surface of the sealing layer 12. This avoids the problem of unreliable circuit board base caused by the loosening of the metal connector 18C due to the exposure of the connection body 18C118C1 and the easy contact of the surface of the sealing layer 12 with foreign objects during the use of the IPM module 10, resulting in the inability of its two bent pins 18C2 to form good electrical connections with the boss and the specific potential part 18D.

[0095] In some embodiments of the present invention, the manufacturing method further includes: injecting a sealing glue into the remaining space of the two fine holes 12A.

[0096] For the IPM module 10 whose circuit board 16 does not need to be grounded, the two fine holes 12A are further filled with the sealing glue, thereby further improving the airtightness and watertightness.

[0097] For the IPM module 10 whose circuit board needs to be grounded, in addition to injecting the sealing glue into the remaining space of the fine hole 12A where the bent pin 18C2 is installed, the remaining space for installing the metal connector 18C in the groove 12B can also be provided with the sealing glue, so as to further strengthen the reliable fixation of the metal connector 18C and further improve the airtightness and watertightness of the IPM module 10.

[0098] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0099] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0100] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0101] In the present invention, unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0102] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0103] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as a limitation on the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An intelligent power module, characterized in that, Comprising: A circuit board made of a metal material; An insulating layer disposed on the surface of the circuit board; A circuit wiring layer provided on the insulating layer; Circuit components disposed on the circuit wiring layer; Multiple pins, with multiple pins provided at at least one side edge of the circuit board, and the pins being electrically connected to the circuit wiring layer; A sealing layer that at least wraps and sets one surface of the substrate where the circuit components are located, and one end of the pins protrudes from the sealing layer; Wherein a boss for electrically connecting the circuit board is further provided on the upper surface of the circuit board, and a specific ground potential portion capable of being electrically connected to the boss is provided on the circuit wiring layer, and the boss and the specific ground potential portion are disposed close to each other; The boss protrudes from the surface of the insulating layer, and the boss is integrally formed with the circuit board; and the height error between the boss and the height of the circuit wiring layer is -0.6 mm to +0.6 mm; the distance between the boss and the specific ground potential portion is 0.5 mm to 2 mm; The surface of the boss is coated with solder paste or silver paste; the specific ground potential portion is electrically connected to the ground pin or the reserved empty pin of the intelligent power module; The sealing layer is respectively provided with fine holes corresponding to the boss and the specific ground potential portion, so that the boss and the specific ground potential portion protrude outward from the fine holes; It further includes a metal connector, the metal connector includes two bent feet formed by bending both ends toward the same side, and a connecting body connecting the bent feet, the foot diameters of the two bent feet are adapted to the sizes of the fine holes, and the two bent feet of the metal connector extend into the fine holes to be respectively electrically connected to the boss and the specific ground potential portion, and the connecting body is mounted on the surface of the sealing layer; The sealing layer is further provided with a groove between the fine holes, the width of the connecting body is adapted to the width of the groove, and the connecting body is mounted in the groove; the remaining space for mounting the metal connector in the fine holes and the groove is provided with sealing glue.

2. The intelligent power module according to claim 1, wherein, One end face of the bent foot is a flat surface, and the width of the connecting body is greater than the foot diameter of the bent foot.

3. A manufacturing method of the intelligent power module according to any one of claims 1 or 2, characterized in that, Including the following steps: Providing a boss on the surface of a circuit board made of a metal material; Providing an insulating layer on the surface of the circuit board except for the boss, and forming a circuit wiring layer on the surface of the insulating layer; Disposing circuit components and pins at corresponding positions on the circuit wiring layer; Connecting metal wires between multiple circuit components or between the circuit components and the pins; The circuit board provided with the circuit components and the pins is injection molded through a packaging mold to form a sealing layer, wherein the sealing layer covers at least one side of the circuit board where the circuit components are provided; the packaging mold is provided with an upper film and a lower film up and down, the pins are fixedly arranged between the upper film and the lower film, and the free ends of at least two ejector pins arranged on the upper film respectively abut against the surface of the boss and a specific ground potential part of the circuit wiring layer. The pins protrude from the sealing layer, and after demolding, the sealing layer forms two corresponding small holes at the positions where the ejector pins abut against the boss and the specific ground potential part. The pins are cut and formed to form the intelligent power module, and the formed intelligent power module is tested.

4. The manufacturing method according to claim 3, characterized in that, The manufacturing method further includes: Manufacturing a metal connector, wherein the metal connector includes two bent feet formed by bending both ends toward the same side and a connecting body connecting the bent feet; Installing the metal connector at the installation position formed by the small holes and the grooves, wherein the two bent feet respectively penetrate into the small holes and abut against the boss and the specific ground potential part to form an electrical connection, and the connecting body is installed on the surface of the sealing layer.

5. The manufacturing method according to claim 4, wherein After the circuit board with the circuit components and the pins is injection molded through a packaging mold to form a sealing layer, the manufacturing method further includes: A groove is provided between the two small holes so that the connecting body is installed in the groove.

Images