Intelligent power module and manufacturing method thereof

Abstract

The present invention provides an intelligent power module and a manufacturing method thereof, comprising: a circuit substrate, wherein a boss is provided at an edge position of the upper surface of the circuit substrate; an insulating layer, wherein the insulating layer covers the upper surface of the circuit substrate but does not cover the boss; a circuit wiring layer, wherein the circuit wiring layer is provided on the insulating layer; a plurality of pins, wherein one pin is electrically connected to the boss, and the remaining pins are electrically connected to the circuit wiring layer; a plurality of circuit elements, wherein the circuit elements are provided at preset positions on the circuit wiring layer, and the plurality of circuit elements or the circuit elements are electrically connected to the circuit wiring layer. The present invention provides a boss at an edge position of the upper surface of the circuit substrate, uses the boss as a grounding potential point of the circuit substrate, and electrically connects the boss through a pin, without drilling holes and bonding wires, thereby improving the reliability and manufacturing yield of the intelligent power module and reducing the manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic device design, and in particular to an intelligent power module and a manufacturing method thereof. Background Art

[0002] Intelligent Power Module (IPM) is a product that combines power electronics and integrated circuit technology for power drive. Existing intelligent power modules integrate power switching devices and high-voltage drive circuits, and have fault detection circuits such as overvoltage, overcurrent and overheating hidden in the module. On the one hand, it receives the control signal of the MCU to drive the subsequent circuit to work, and on the other hand, it sends the system status detection signal back to the MCU. Compared with the traditional solution of separate power switching devices and high-voltage drive circuits, the intelligent power module has won an increasingly large market with its advantages of high integration and high reliability. It is especially suitable for frequency converters and various inverter power supplies for driving motors. It is an ideal power electronic device for variable frequency speed regulation, metallurgical machinery, electric traction, servo drive, and variable frequency home appliances.

[0003] The structure of a conventional intelligent power module 100 is described with reference to Fig. 1. Fig. 1(A) is a top view of the intelligent power module 100, and Fig. 1(B) is a cross-sectional view taken along line XX' of Fig. 1(A).

[0004] The intelligent power module 100 in the prior art has the following structure, which includes: a circuit substrate 106, an insulating layer 107 arranged on the surface of the circuit substrate 106, a circuit wiring 108 formed on the insulating layer 107, a circuit element 104 fixed on the circuit wiring 108, a metal wire 105 connecting the circuit element 104 and the circuit wiring 108, a pin 101 connected to the circuit wiring 108, and a resin 102 that seals the intelligent power module 100.

[0005] In the process of implementing the technical solution of the present invention, the inventors found that:

[0006] In the current manufacturing process of the intelligent power module 100, if the circuit substrate needs to be connected to the ground potential, a drilling process is generally required to drill through the insulating layer 107, and then form an electrical connection between the ground potential of the circuit wiring 108 and the circuit substrate 106 through the bonding wire. The drilling position and the flatness of the bottom of the hole in this process are difficult to control. Poor drilling position and poor flatness of the bottom of the hole will directly affect the reliability of the bonding wire. If the bonding wire is unreliable, problems such as disconnection will occur, causing the intelligent power module to be scrapped, resulting in a low yield in the manufacturing process and an increase in manufacturing costs.

[0007] Therefore, the prior art has defects and is in urgent need of improvement. Summary of the invention

[0008] The purpose of the embodiments of the present invention is to provide an intelligent power module and a manufacturing method thereof, so as to solve the problems of low yield and high manufacturing cost of the existing intelligent power modules.

[0009] An embodiment of the present invention provides an intelligent power module, comprising:

[0010] A circuit substrate, wherein a boss is provided at an edge position of an upper surface of the circuit substrate;

[0011] an insulating layer, the insulating layer covering the upper surface of the circuit substrate but not covering the boss;

[0012] A circuit wiring layer, wherein the circuit wiring layer is disposed on the insulating layer;

[0013] A plurality of pins, one of which is electrically connected to the boss, and the remaining pins are electrically connected to the circuit wiring layer;

[0014] A plurality of circuit elements are provided at preset positions on the circuit wiring layer, and the plurality of circuit elements are electrically connected to each other or the circuit elements and the circuit wiring layer are electrically connected to each other.

[0015] In the intelligent power module, the sum of the thickness of the insulating layer and the circuit wiring layer differs from the height of the boss by between -0.5 mm and 0.5 mm.

[0016] In the intelligent power module, a plurality of pads are provided at the edge of the circuit wiring layer, the plurality of pads are aligned with the bosses, and the plurality of pads are electrically connected to the remaining pins in a one-to-one correspondence.

[0017] In the intelligent power module, the pad and the boss are both connected to the pin via a conductive adhesive material with fluidity, and the conductive adhesive material is solder paste or silver glue.

[0018] In the intelligent power module, the insulating layer is an epoxy resin layer or an organic silicone layer, the epoxy resin layer or the organic silicone layer contains a high thermal conductivity material, and the high thermal conductivity material is angular or spherical.

[0019] The intelligent power module further comprises a sealing resin layer, wherein the sealing resin layer is wrapped around the outside of the circuit substrate provided with the plurality of circuit elements.

[0020] A method for manufacturing an intelligent power module, comprising the following steps:

[0021] Manufacturing a circuit substrate, and forming a boss at an edge position of an upper surface of the circuit substrate;

[0022] An insulating layer is covered on the upper surface of the circuit substrate, but not on the boss;

[0023] Fabricating a circuit wiring layer on the insulating layer;

[0024] Make multiple pins;

[0025] Mounting one of the pins on the boss, mounting the remaining pins on the circuit wiring layer, and mounting a plurality of circuit elements at preset positions on the circuit wiring layer;

[0026] Wire bonding is performed between a plurality of the circuit elements or between the circuit element and the circuit wiring layer.

[0027] The method for manufacturing the intelligent power module, wherein the step of making a circuit wiring layer on the insulating layer comprises the following steps:

[0028] Laminating a layer of copper foil on the insulating layer;

[0029] The copper foil is etched to form the circuit wiring layer having a plurality of pads at the edge.

[0030] The method for manufacturing the intelligent power module, wherein the step of assembling one of the pins on the boss, assembling the remaining pins on the circuit wiring layer, and assembling a plurality of circuit elements at preset positions on the circuit wiring layer comprises the following steps:

[0031] Apply solder paste or silver glue on the preset position on the circuit wiring layer, on the pad and on the boss;

[0032] Fixing one end of the pin on the pad and the boss correspondingly;

[0033] The circuit element is fixed at a preset position on the upper surface of the circuit wiring layer.

[0034] The method for manufacturing the intelligent power module, wherein the step further comprises the following steps after bonding wires between the plurality of circuit elements or between the circuit elements and the circuit wiring layer:

[0035] The sealing resin layer is encapsulated outside the circuit substrate provided with the plurality of circuit elements by injection molding of a thermoplastic resin or transfer molding of a thermosetting resin.

[0036] Beneficial effects: The embodiment of the present invention sets a boss at the edge of the upper surface of the circuit substrate, uses the boss as the grounding potential point of the circuit substrate, and electrically connects the boss through a pin without drilling holes and bonding wires, thereby improving the reliability and manufacturing yield of the intelligent power module and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0038] Figure 1A The figure is a top view of an existing intelligent power module.

[0039] Figure 1B is along Figure 1A X-X' line cross-section diagram.

[0040] Figure 2A FIG. 4 is a top view of an intelligent power module according to an embodiment of the present invention.

[0041] Figure 2B is along Figure 2A X-X' line cross-section diagram.

[0042] Figure 2C yes Figure 2A Top view with the sealing resin removed.

[0043] Figure 3A The present invention is a top view of a circuit substrate formed after the step of manufacturing a circuit wiring layer on an insulating layer in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0044] Figure 3B yes Figure 3A X-X' line cross-section diagram.

[0045] Figure 4A It is a top view of a pin formed after a step of manufacturing a plurality of pins in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0046] Figure 4B It is a top view of another type of pin formed after the step of manufacturing multiple pins in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0047] Figure 5A It is a top view of a circuit substrate formed after assembling one of the pins on the boss, assembling the remaining pins on the circuit wiring layer, and assembling multiple circuit elements at preset positions on the circuit wiring layer in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0048] Figure 5B yes Figure 5A X-X' line cross-section diagram.

[0049] Fig. 6A It is a top view of a circuit substrate formed after a wire bonding step is performed between a plurality of circuit elements or between the circuit element and the circuit wiring layer in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0050] Figure 6B yes Fig. 6A X-X' line cross-section diagram.

[0051] Figure 7 It is a cross-sectional view of a circuit substrate in the step of encapsulating a sealing resin layer on the outside of the circuit substrate provided with a plurality of circuit elements by injection molding of a thermoplastic resin or transfer molding of a thermosetting resin in a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0052] Figure 8 A method for manufacturing an intelligent power module according to an embodiment of the present invention is provided, wherein the pins on the boss are cut off or retained to obtain a top view of the intelligent power module formed after the step of obtaining the intelligent power module.

[0053] Fig. 9 The present invention is a flowchart of a method for manufacturing an intelligent power module according to an embodiment of the present invention.

[0054] Explanation of the accompanying drawings: 10, intelligent power module; 11, pin; 12, sealing resin layer; 14, circuit element; 15, metal wire; 16, circuit substrate; 17, insulating layer; 18, circuit wiring layer; 18A, pad; 18B, boss; 20, carrier; 44, upper model; 45, lower model; 46, pin fixing device; 51, shaping line; 53, gate; 54, exhaust port. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0056] In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "upper surface", "lower surface", etc. is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the invention is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] like Figures 2A to 2C As shown, an intelligent power module 10 according to an embodiment of the present invention, wherein: Figure 2A A top view of an intelligent power module according to an embodiment of the present invention is shown; Figure 2B Shown along Figure 2A X-X' line cross-section diagram; Figure 2C Shows Figure 2A The intelligent power module 10 includes:

[0059] A circuit substrate 16, wherein a boss 18B is provided at an edge position of an upper surface of the circuit substrate 16;

[0060] An insulating layer 17, the insulating layer 17 covers the upper surface of the circuit substrate 16 but does not cover the boss 18B;

[0061] A circuit wiring layer 18, wherein the circuit wiring layer 18 is disposed on the insulating layer 17;

[0062] A plurality of pins 11, one of which is electrically connected to the boss 18B, and the remaining pins 11 are electrically connected to the circuit wiring layer 18;

[0063] A plurality of circuit elements 14 are disposed at predetermined positions on the circuit wiring layer 18 , and the plurality of circuit elements 14 or the circuit elements 14 and the circuit wiring layer 18 are electrically connected.

[0064] The sum of the thickness of the insulating layer 17 and the circuit wiring layer 18 differs from the height of the boss 18B by -0.5 mm to 0.5 mm, and the sum of the thickness of the insulating layer 17 and the circuit wiring layer 18 is substantially consistent with the height of the boss 18B, thereby maintaining the flatness of the intelligent power module 10 .

[0065] Furthermore, a plurality of pads 18A are provided at the edge of the circuit wiring layer 18, and the plurality of pads 18A are used to be electrically connected to the remaining pins 11 in a one-to-one correspondence, and the plurality of pads 18A are aligned with the boss 18B. Among them, one end of the pin 11 is connected to the boss 18B or the pad 18A, and the other end extends outside the intelligent power module 10 and is connected to the external circuit, and is used as an input and output component of the intelligent power module 10.

[0066] It should be noted that the pad 18A and the boss 18B are bonded to the pin 11 by a conductive adhesive material having fluidity, wherein the conductive adhesive material can be solder paste or silver glue. Figure 1A and Figure 1B As shown, if the circuit substrate 106 of the existing intelligent power module 100 needs to be connected to the ground potential, it is necessary to turn through the insulating layer 107 through the hole, and then form an electrical connection between the circuit substrate 106 and the ground potential of the circuit wiring 108 through the bonding wire. However, this method has the following problems: First, in the hole turning process, the hole turning position is difficult to control, and the flatness of the bottom of the hole cannot be controlled. The difficulty in controlling the hole turning position and the poor flatness of the bottom of the hole will directly affect the reliability of the bonding wire. If the bonding wire is unreliable, it is easy to have problems such as disconnection, causing the entire intelligent power module 100 to be scrapped, resulting in a low yield rate in the manufacturing process, a high defective rate, and an increase in manufacturing costs; second, the existing intelligent power module 100 generally works at a switching frequency of 10kHz to 40kHz. Experiments show that for an operating frequency of 10kHz to 20kHz, if the circuit substrate 106 is connected to the ground potential, the probability of false triggering of the intelligent power module 100 during operation is lower. For the operating frequency of 20kHz to 40kHz, if the circuit substrate 106 is connected to the ground potential, the probability of false triggering of the intelligent power module 100 during operation is higher. The electrical connection between the circuit substrate 106 and the ground potential of the circuit wiring 108 is formed through the drilling process and then through the bonding wire, which is only a change in the internal structure of the module. Since the circuit substrate 106 is connected to the ground potential of the circuit wiring 108, the ground potential of the circuit wiring 108 must be grounded. Once packaged, it cannot be changed. Only a power module with the circuit substrate 106 grounded can be obtained, which is poor in usability. If two intelligent power modules are specially designed for applications with different operating frequencies, it will increase costs. Moreover, since the ground potential of the circuit wiring 108 is connected internally through the bonding wire, it has the same appearance as the internally ungrounded intelligent power module. Whether in the production and delivery link or the assembly and application link, there is a risk of mixing materials. The increase in cost is not conducive to the application and promotion of intelligent power modules. Once mixing occurs, it will cause false triggering during the use of the intelligent power module, reducing the user experience of the intelligent power module. In severe cases, it may even cause the intelligent power module body and the electrical appliance body to burn, with serious consequences. The intelligent power module 10 in the embodiment of the present invention directly connects a pin 11 to the boss 18B of the circuit substrate 16 through solder paste, pins and other adhesive materials, and uses the pin 11 connected to the boss 18B as a ground pin of the circuit substrate 16 alone, eliminating the difficult-to-control hole-turning process, and instead uses the adhesive material to achieve the potential connection of the circuit substrate 16, thereby improving the reliability and manufacturing yield of the intelligent power module and reducing the manufacturing cost.

[0067] Furthermore, each pin 11 is made of conductive materials such as a copper substrate, and a layer of nickel-tin alloy is arranged on the surface of the pin 11. The thickness of the nickel-tin alloy is generally controlled at 5μm. The setting of the nickel-tin alloy can protect the copper substrate in the middle of the pin 11 from corrosion and oxidation, greatly improving the protection and solderability.

[0068] In practical applications, the insulating layer 17 is an epoxy resin layer or an organic silicone layer, and the insulating layer 17 is filled with high-concentration aluminum oxide, silicon carbide aluminum and other high-thermal conductivity materials to improve thermal conductivity, thereby improving the heat dissipation performance of the module. The high-thermal conductivity material can be an angular material to improve the thermal conductivity of the module; the high-thermal conductivity material can also be a spherical material to avoid the risk of the angular high thermal conductivity damaging the surface of the circuit element 14. Among them, the lower surface of the circuit substrate 16 can also be provided with an insulating layer 17 filled with a high-concentration high-thermal conductivity material to dissipate heat for the circuit substrate 16, and a corrosion-resistant layer can also be formed on the lower surface of the circuit substrate 16 to prevent some chemicals from etching the lower surface of the circuit substrate 16 during the processing process, thereby affecting the quality of the module.

[0069] In addition, an intelligent power module 10 according to an embodiment of the present invention further includes a sealing resin layer 12, which can be a thermoplastic resin or a thermosetting resin. The sealing resin layer 12 is wrapped around the outside of a circuit substrate 16 provided with a plurality of circuit elements 14, and seals and encapsulates the plurality of circuit elements 14 and electronic components such as a circuit wiring layer exposed on the upper surface of the circuit substrate 16. In practical applications, for intelligent power modules 10 with high density requirements, the lower surface of the circuit substrate 16 is generally also sealed to encapsulate a layer of resin; for intelligent power modules 10 with high heat dissipation requirements, the lower surface of the circuit substrate 16 is exposed and not sealed.

[0070] It should be noted that the preset position on the circuit wiring layer 18 in the embodiment of the present invention refers to a position pre-designed to realize the required circuit. In practical applications, the circuit can be a power drive circuit composed of a driver IC + multiple insulated gate bipolar transistors (IGBT). Correspondingly, the circuit element 14 can be a driver chip, an IGBT or a fast recovery diode, etc. Alternatively, according to the required circuit, the circuit element 14 can also use active components such as transistors or diodes, or passive components such as capacitors or resistors. In addition, the circuit element 14 can also be a heat sink made of high thermal conductivity materials such as copper and aluminum, which is arranged next to a power device with a large heat generation for efficient heat dissipation.

[0071] In practical applications, the connection between multiple circuit elements 14 or between circuit elements 14 and circuit wiring layer 18 refers to the connection of corresponding lines according to a pre-designed circuit. Multiple circuit elements 14 or between circuit elements 14 and circuit wiring layer 18 can be electrically connected through metal wires 15. Metal wires 15 can be aluminum wires, gold wires or copper wires. Through bonding, electrical connections are established between circuit elements 14, between circuit wirings 18, and between circuit elements 14 and circuit wirings 18 to form the required circuit. Sometimes metal wires 15 are also used to establish electrical connections between pins 11 and circuit wirings 18 or circuit elements 14. Here, the thickness of the metal wire 15 should be comprehensively considered based on the size of the bonding point, the required current-carrying capacity, the machinability of the components, etc. Generally, the diameter of a single metal wire should not be greater than 400μm and should not be less than 15μm. For the connection of power devices, consider using multiple 400μm aluminum wires for bonding in parallel or using aluminum bars for bonding. For the connection of functional devices, consider using a single 38μm aluminum wire for bonding. Here, the thickness of the metal wire 15 is not limited.

[0072] The embodiment of the present invention also provides a method for manufacturing an intelligent power module. Fig. 9 As shown, the following steps are included:

[0073] S1, manufacturing a circuit substrate, and forming a boss at an edge position of an upper surface of the circuit substrate;

[0074] S2, covering the upper surface of the circuit substrate with an insulating layer, but not covering the boss;

[0075] S3, making a circuit wiring layer on the insulating layer;

[0076] S4, making multiple pins;

[0077] S5, assembling a pin on the boss, assembling the remaining pins on the circuit wiring layer, and assembling a plurality of circuit components at preset positions on the circuit wiring layer;

[0078] S6. Make wire bonding connections between multiple circuit elements or between circuit elements and circuit wiring layers.

[0079] In order to demonstrate the superiority of the manufacturing method provided by the embodiment of the present invention, the above steps are described in detail below.

[0080] First, the three steps of making a circuit substrate are introduced, namely, forming a boss S1 at the edge of the upper surface of the circuit substrate, covering the upper surface of the circuit substrate with an insulating layer but not covering the boss S2, and making a circuit wiring layer S3 on the insulating layer. Figure 3A and 3B The specific structure of the circuit substrate after the above three steps is shown. Figure 3Ais a top view of the circuit substrate; Figure 3B yes Figure 3A X-X' line cross-section diagram.

[0081] First, the circuit substrate 16 is made of aluminum such as 1100, 5052, etc. A circuit substrate 16 of suitable size and shape is designed according to the required circuit layout. For a general intelligent power module, its shape is rectangular, and the size can be selected as 64mm×30mm. Here, the size and shape of the circuit substrate 16 are not limited. A boss 18B is formed at the edge of the circuit substrate 16 by etching, stamping, etc. Here, the method of forming the boss 18B can be laser etching, mechanical pressure, and flat-bottom rotary head grinding.

[0082] Then, there are two methods for forming the insulating layer 17 on the upper surface of the circuit substrate 16 and forming the circuit wiring layer 18 on the insulating layer 17: the first method is to perform anti-corrosion treatment on at least one surface of the circuit substrate 16, and then form the circuit wiring layer 18 on the side of the circuit substrate 16 with the boss 18B; the second method is to directly form the insulating layer 17 on at least one surface of the circuit substrate 16, and then form the circuit wiring layer 18 on the side of the circuit substrate 16 with the boss 18B. In the intelligent power manufacturing method of the embodiment of the present invention, both sides of the circuit substrate 16 are subjected to anti-corrosion treatment. For the fully sealed intelligent power module, in order to save costs, the anti-corrosion treatment may not be performed, and the insulating layer 17 may be directly provided on the side of the circuit substrate 16 with the boss 18B.

[0083] Next, a copper foil as a circuit wiring layer 18 is laminated on the surface of the insulating layer 17. The copper foil is preferably a copper foil of not less than two ounces. The insulating layer 17 does not cover the boss 18B. At the same time, the height of the insulating layer 17 and the copper foil is substantially consistent with the height of the boss 18B. The copper foil is then etched to partially remove the copper foil to form the circuit wiring layer 18, and a plurality of pads 18A are formed at the edge of the circuit wiring layer 18. The pads 18A are aligned with the boss 18A.

[0084] Here, the circuit substrate 16 of suitable size is formed by directly rouging a 1m×1m aluminum material. The rouging cutter is made of high-speed steel, the motor uses a rotation speed of 5000 rpm, and the rouging cutter is cut at a right angle to the plane of the aluminum material. The circuit substrate 16 can also be formed by stamping.

[0085] Second, the step of making multiple pins S4 is introduced. Figure 4A and 4B The specific structures of two types of pins 11 are shown.

[0086] like Figure 4A As shown, Figure 4AThe pin 11 shown is in the shape of a strip with a length C of 25 mm, a width K of 1.5 mm, and a thickness H of 1 mm. Figure 4B As shown, Figure 4A Another type of pin 11 is shown, in which a certain curvature is pressed at one end to facilitate assembly.

[0087] Furthermore, a nickel-tin alloy layer is formed on the surface of the pin 11 by chemical plating: first, a nickel layer is formed on the surface of the copper material that has been formed into a specific shape by a mixed solution of nickel salt and sodium hypophosphite, and an appropriate chelating agent is added to the mixed solution. Metallic nickel has a strong passivation ability and can quickly generate an extremely thin passivation film that can resist corrosion from 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 acid sulfate process, the copper material with a nickel layer on the surface is immersed in a plating solution with positive tin ions at room temperature and electrified to form a nickel-tin alloy layer on the surface of the nickel layer, thereby greatly improving the protection and solderability, and completing the manufacture of the pin 11.

[0088] Thirdly, a step of assembling a pin on the boss, assembling the remaining pins on the circuit wiring layer, and assembling a plurality of circuit elements S5 at preset positions on the circuit wiring layer is introduced. Figure 5A A top view of the circuit substrate formed after step S5 is shown; Figure 5B yes Figure 5A X-X' line cross-section diagram.

[0089] First, use a solder paste printer and a steel mesh to apply solder paste to the preset position of the circuit wiring layer 18. The steel mesh can use a thickness of 0.13mm. In addition, a silver glue dispenser can be used to apply a specific pattern at the preset position with silver paste. Among them, solder paste or silver glue must be applied to the pad 18A and the boss 18B.

[0090] Then, refer to Figure 5A and Figure 5B , the circuit element 14 and the plurality of pins 11 are installed. The circuit element 14 can be directly placed at the preset position of the circuit wiring layer 18, and one end of the pin 11 is placed on the pad 18A, and the other end is fixed by the carrier 20. The carrier 20 is provided with a support plate at one end of the pin 11, which can fix the pin 11 extending out of the module. The carrier 20 is made of synthetic stone, stainless steel and other materials. Among them, one pin 11 is placed on the boss 18B, and the remaining pins 11 are placed on the pad 18A.

[0091] Next, the circuit substrate 16 on the carrier 20 is subjected to reflow soldering to solidify the solder paste or silver paste, and the circuit element 14 and the pin 11 are fixed.

[0092] Fourthly, a step S6 of performing wire bonding between a plurality of circuit elements or between a circuit element and a circuit wiring layer is introduced. Fig. 6A A top view of the circuit substrate formed after step S6 is shown; Figure 6B yes Fig. 6A X-X' line cross-section diagram.

[0093] First, the circuit substrate 16 is placed in a cleaning machine for cleaning, and the residual flux such as rosin during reflow soldering in step S5 and the residual foreign matter such as aluminum wire during stamping are cleaned. According to the arrangement density of the circuit elements 14 on the circuit wiring layer 18, the cleaning can be performed by spraying or ultrasound or a combination of the two. During cleaning, two or more pins 11 are clamped by a mechanical arm, and the circuit substrate 16 is placed in a cleaning tank; the cleaning method can be spraying or ultrasound. If the circuit element 14 has a device with a thickness of 60 to 70 μm, the energy of the spraying or ultrasound cannot be too high.

[0094] Then, according to the required circuit, metal wires 15 of a certain diameter are bonded at the preset positions of the circuit elements 14 and the circuit wiring 18 to form electrical connections.

[0095] Furthermore, the method for manufacturing the intelligent power module of the embodiment of the present invention further includes the following steps after the step of performing wire bonding connection S6 between a plurality of circuit elements or between a circuit element and a circuit wiring layer:

[0096] The sealing resin layer is encapsulated outside the circuit substrate provided with a plurality of circuit elements by injection molding of a thermoplastic resin or transfer molding of a thermosetting resin.

[0097] like Figure 7 As shown, Figure 7 The cross-sectional view of the circuit substrate 16 in the above steps is shown. Specifically:

[0098] First, the circuit substrate 16 is baked in an oxygen-free environment. The baking time is not less than 2 hours and the baking temperature is selected to be 125°C.

[0099] Then, the circuit board 16 with the pins 11 arranged thereon is conveyed to the mold, which includes an upper mold 44 and a lower mold 45. The circuit board 16 is positioned by bringing the ends of the pins 11 away from the pads 18A and the bosses 18B into contact with the pin fixing device 46.

[0100] Next, when the mold is closed, the circuit substrate 16 is placed in the cavity formed inside the mold 50, and then the sealing resin 12 is injected from the gate 53. The sealing method can be a transfer mold molding using a thermosetting resin or an injection mold molding using a thermosetting resin. In addition, the gas inside the cavity corresponding to the sealing resin 12 injected from the gate 53 is discharged to the outside through the exhaust port 54.

[0101] exist Figure 7 In the embodiment shown, the intelligent power module is a fully sealed design. The widths of the injection molding channels on the upper and lower surfaces in the figure are inconsistent. Generally speaking, the channel width on the upper surface is much larger than the channel width on the lower surface. For this type of intelligent power module, it should be noted that the injection molding pressure should be designed to be relatively large to avoid insufficient injection molding of the lower surface. For a semi-sealed design with the lower surface exposed, the injection molding pressure can be designed to be relatively small to avoid the risk of hitting the line due to excessive injection molding pressure.

[0102] In actual application, when using the intelligent power module in the embodiment of the present invention, the pin 11 connected to the boss 18B can be cut off or retained, and grounded or not grounded according to the situation. The pin 11 can also be cut off or retained in the production process and sold in categories. Specifically, after the step of encapsulating the sealing resin layer on the outside of the circuit substrate with multiple circuit elements, the pin 11 configured on the boss 18B is cut off or retained according to whether the circuit substrate 16 needs to be grounded, and then the pin 11 is shaped according to the length and shape required for use, for example, Figure 8 As shown, Figure 8 A top view of the circuit substrate formed after step S7 is shown. Figure 8The circuit substrate 16 of the intelligent power module 10 in the circuit needs to be grounded, so the pins are not cut off, and the external pins 11 are bent into a certain shape at the position of the shaping line 51 to facilitate the user's subsequent assembly. However, the existing intelligent power module is connected to the ground potential of the circuit wiring 108 through the bonding wire inside, and its appearance is the same as the internal ungrounded intelligent power module. Whether in the production and delivery link or the user's assembly and application link, there is a risk of mixing materials. The increase in cost is not conducive to the application and promotion of intelligent power modules. Once mixing occurs, it will cause false triggering during the use of the intelligent power module, reducing the user experience of the intelligent power module. In severe cases, it may even cause the intelligent power module body and the electrical appliance body to burn, with serious consequences. In the intelligent power module 10 in the embodiment of the present invention, the pin 11 connected to the boss 18B is the ground pin of the circuit substrate 16. When the circuit substrate 16 needs to be grounded, the pin 11 can be retained, and the pin 11 is connected to the ground potential in the application circuit. When the circuit substrate 16 is not needed to be grounded, the pin 11 can be cut off, that is, the circuit substrate 16 is suspended. Without adding production processes, the two design schemes are flexibly manufactured. The manufacturing method lacks the difficult-to-control hole-turning process, and the potential connection of the circuit substrate 16 is realized by bonding materials, thereby improving the reliability and manufacturing yield of the intelligent power module. At the same time, the grounding of the circuit substrate 16 is optional under the same design, which can be generally applicable to the application of two switching frequencies of 10kHz to 20kHz and 20kHz to 40kHz, reducing the development cost; and for the intelligent power module that needs to be grounded, there will be one more pin 11 in its appearance, and for the intelligent power module that does not need to be grounded, there will be one less pin 11 in its appearance, and there is a difference between the two, thereby avoiding the occurrence of mixing.

[0103] In addition, after the step of cutting off or retaining the pins on the bosses to obtain the intelligent power module S7, the manufacturing method of the intelligent power module of the embodiment of the present invention also includes the step of testing the module function and appearance: placing the module in the test equipment and performing conventional electrical parameter tests, generally including insulation withstand voltage, static power consumption, delay time and other test items; then performing appearance AOI tests, generally including assembly hole size, pin offset and other test items, and those that pass the test are finished products.

[0104] The embodiment of the present invention sets a boss at the edge position of the upper surface of the circuit substrate, uses the boss as the grounding potential point of the circuit substrate, and electrically connects the boss through a pin. When the circuit substrate needs to be grounded, the pin is not cut off, and the pin is connected to the ground potential in the application circuit, that is, the circuit substrate is grounded. When the circuit substrate is not needed to be grounded, the pin is cut off, that is, the circuit substrate is suspended from the ground. Without adding production processes, the manufacture of two design schemes is realized. The manufacturing method omits the difficult-to-control hole-turning process, and instead realizes the potential connection of the circuit substrate through an adhesive material, thereby improving the reliability and manufacturing yield of the intelligent power module.

[0105] In addition, the embodiments of the present invention make it possible to select whether the circuit substrate is grounded or not under the same design, and can be generally applicable to applications with two switching frequencies of 10kHz to 20kHz and 20kHz to 40kHz, thereby reducing development costs. In addition, for an intelligent power module that needs to be grounded, there will be one more pin on its appearance, and for an intelligent power module that does not need to be grounded, there will be one less pin on its appearance, and there is a difference between the two, thereby avoiding the occurrence of material mixing.

[0106] The above descriptions are only embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Unless otherwise clearly specified and limited, the terms "setting" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An intelligent power module, characterized in that: include: A circuit substrate, wherein the circuit substrate is made of a conductive material, a boss is provided at an edge of an upper surface of the circuit substrate, and the boss is a grounding potential point of the circuit substrate; an insulating layer, the insulating layer covering the upper surface of the circuit substrate but not covering the boss; A circuit wiring layer, wherein the circuit wiring layer is disposed on the insulating layer; A plurality of pins, one of which is electrically connected to the boss, and the remaining pins are electrically connected to the circuit wiring layer; A plurality of circuit elements are provided at preset positions on the circuit wiring layer, and the plurality of circuit elements are electrically connected to each other or the circuit elements and the circuit wiring layer are electrically connected to each other.

2. The intelligent power module according to claim 1, characterized in that: The sum of the thicknesses of the insulating layer and the circuit wiring layer differs from the height of the boss by -0.5 mm to 0.5 mm.

3. The intelligent power module according to claim 1, characterized in that: A plurality of pads are arranged at the edge of the circuit wiring layer, the plurality of pads are aligned with the bosses, and the plurality of pads are electrically connected to the remaining pins in a one-to-one correspondence.

4. The intelligent power module according to claim 3, characterized in that: The pad and the boss are both connected to the pin via a conductive adhesive material with fluidity, and the conductive adhesive material is solder paste or silver glue.

5. The intelligent power module according to claim 1, characterized in that: The insulating layer is an epoxy resin layer or an organic silicone layer, the epoxy resin layer or the organic silicone layer contains a high thermal conductivity material, and the high thermal conductivity material is angular or spherical.

6. The intelligent power module according to claim 1, characterized in that: It also includes a sealing resin layer, which is wrapped around the outside of the circuit substrate on which the plurality of circuit elements are provided.

7. A method for manufacturing an intelligent power module, characterized in that: The following steps are involved: A circuit substrate is made of a conductive material, and a boss is formed at an edge of an upper surface of the circuit substrate as a grounding potential point of the circuit substrate; An insulating layer is covered on the upper surface of the circuit substrate, but not on the boss; Fabricating a circuit wiring layer on the insulating layer; Make multiple pins; Mounting one of the pins on the boss, mounting the remaining pins on the circuit wiring layer, and mounting a plurality of circuit elements at preset positions on the circuit wiring layer; Wire bonding is performed between a plurality of the circuit elements or between the circuit element and the circuit wiring layer.

8. The method for manufacturing an intelligent power module according to claim 7, characterized in that: The step of making a circuit wiring layer on the insulating layer comprises the following steps: Laminating a layer of copper foil on the insulating layer; The copper foil is etched to form the circuit wiring layer having a plurality of pads at the edge.

9. The method for manufacturing an intelligent power module according to claim 8, characterized in that: The step of assembling one of the pins on the boss, assembling the remaining pins on the circuit wiring layer, and assembling a plurality of circuit elements at a preset position on the circuit wiring layer comprises the following steps: Apply solder paste or silver glue on the preset position on the circuit wiring layer, on the pad and on the boss; Fixing one end of the pin on the pad and the boss correspondingly; The circuit element is fixed at a preset position on the upper surface of the circuit wiring layer.

10. The method for manufacturing an intelligent power module according to claim 7, characterized in that: After bonding wires between the plurality of circuit elements or between the circuit elements and the circuit wiring layer, the step further includes the following steps: The sealing resin layer is encapsulated outside the circuit substrate provided with the plurality of circuit elements by injection molding of a thermoplastic resin or transfer molding of a thermosetting resin.

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