Intelligent power module and manufacturing method thereof

Abstract

The present invention relates to an intelligent power module and a manufacturing method thereof. An integral lead frame is formed, pins are connected to the frame body, and the circuit board and the frame body are connected by means of metal wires. Therefore, during the manufacturing process of the IPM module, it is not necessary to place it in a packaging mold as in the prior art to provide a supporting force for the circuit board during the injection molding process. Instead, the lead frame is connected to the circuit board by means of metal wires, which avoids the phenomenon that during the injection molding process in the prior art, due to the injection of injection molding materials such as liquid high-pressure resin, stress is generated between the pins and the circuit board, resulting in the dielectric layer stratification of the insulating layer of the circuit board, and ultimately leading to the failure of the entire IPM module manufacturing and a reduction in the manufacturing yield. Therefore, the IPM module of the present invention based on the structure of the lead frame avoids the above problems during the injection molding process and effectively improves the manufacturing yield of the IPM module.

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 the existing IPM (Intelligent Power Module), the module pins and the substrate are connected together by soldering. It is easy to generate stress (the stress generated by the combined tolerance of the substrate and the pins and the tolerance of the mold under the action of the ejector pin), which causes the insulation medium to delaminate, affecting the reliability and thus reducing the production yield of the IPM module. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to solve the problem that when manufacturing the existing IPM module, due to the connection of the pins and the substrate by soldering, the generated tension causes the insulation medium of the substrate to delaminate, ultimately reducing the production yield.

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

[0005] A lead frame, which includes a frame body and pins arranged on the periphery of the frame body. An installation vacancy is provided in the center of the frame body.

[0006] A circuit board, on the surface of which a wiring layer is provided. The circuit board is arranged in the installation vacancy and is electrically connected to the lead frame through metal wires.

[0007] Circuit components, which are arranged on the wiring layer.

[0008] A sealing layer, which at least wraps one side of the circuit board where the circuit components are arranged. One end of the pin exposes from the sealing layer.

[0009] Optionally, an electronic circuit is further configured on the frame body, and a driving IC and passive devices electrically connected to the electronic circuit are provided.

[0010] Optionally, a plurality of pads are provided on the frame body, and the driving IC and passive devices are installed on the pads; a bonding portion formed by a plurality of bonding areas is further provided on the frame body, and the wiring layer is electrically connected to the bonding portion through metal wires.

[0011] Optionally, the sealing layer includes a first sealing layer and a second sealing layer. The first sealing layer is arranged on the remaining part of the lead frame except the installation vacancy. The surface of the lead frame where the driving IC and passive devices are installed is located on the surface of the first sealing layer. The first sealing layer is provided with a side wall protruding upward at the periphery. The side wall and the lead frame and the circuit board form an installation chamber. The second sealing layer is arranged in the installation chamber; the hardness of the second sealing layer is lower than that of the first sealing layer material.

[0012] Optionally, the inner side of the sealing layer located at the pin is inclined inward from the surface and bottom surface respectively facing the sealing layer at the mounting pin to form a first demolding slope, and the angle formed between the first demolding slope and the vertical plane in the up and down direction is 2° to 9°.

[0013] Optionally, the side of the circuit board close to the pin is inclined outward from top to bottom to form a second demolding slope, and the angle formed between the second demolding slope and the vertical plane in the up and down direction is 4° to 10°; the first sealing layer is provided with a stepped portion, and the stepped portion abuts against the edge of the surface of the circuit board.

[0014] Optionally, the lead frame and the wiring layer are connected by a wire bonding process.

[0015] Optionally, a plurality of lead frames are arranged side by side and connected to each other to form a frame assembly.

[0016] The present invention also discloses a manufacturing method of the intelligent power module according to the above, which is characterized in that it includes the following steps:

[0017] Place the lead frame in the frame forming die, and the pins of the lead frame are exposed from both sides of the frame forming die;

[0018] Inject plastic into the frame forming die to form a semi-finished product with a first sealing layer. The first sealing layer is arranged on the remaining part of the frame body except the mounting vacancy. The mounting surface of the lead frame is exposed from the surface of the sealing layer. The first sealing layer is provided with a side wall protruding upward on the side where the pin is located, and the pin is exposed from both sides of the first sealing layer;

[0019] Configure the circuit board and form a wiring layer on the surface of the circuit board;

[0020] Arrange circuit elements at corresponding positions of the wiring layer;

[0021] Place the semi-finished product and the circuit board configured with circuit elements in the tooling fixture, wherein the circuit board is arranged in the mounting vacancy of the lead frame, and the side wall forms a mounting chamber with the lead frame and the circuit board;

[0022] Connect metal wires between the wiring layer and the lead frame to form a complete circuit connection;

[0023] Inject glue into the mounting chamber to form a second sealing layer, which together with the first sealing layer forms the sealing layer of the intelligent power module, wherein the hardness of the second sealing layer is lower than that of the first sealing layer material.

[0024] Optionally, after the injection molding step, the manufacturing method further includes:

[0025] Set a plurality of pads on the surface of the frame body of the lead frame;

[0026] It will replace the IC and passive components and be installed on the pads.

[0027] Optionally, after the step of potting the installation chamber, the manufacturing method further includes:

[0028] Forming and electroplating the exposed pins to form a protective layer on the surface of the pins.

[0029] The present invention also discloses a manufacturing method of an intelligent power module according to the above, characterized by including the following steps:

[0030] Place the lead frame in the frame forming die, and the pins of the lead frame expose from both sides of the frame forming die;

[0031] Configure the circuit board and form a wiring layer on the surface of the circuit board;

[0032] Place the circuit board in the die cavity, where the circuit board is arranged in the installation vacancy of the lead frame;

[0033] Inject plastic into the frame forming die to form a semi-finished product with a first sealing layer. The first sealing layer is arranged on the remaining part of the frame body except the installation vacancy. The installation surface of the lead frame exposes from the surface of the sealing layer. The first sealing layer is provided with upward protruding side walls at the periphery. The pins expose from both sides of the first sealing layer. The side walls and the lead frame and the circuit board form an installation chamber;

[0034] Arrange circuit elements at corresponding positions of the wiring layer;

[0035] Connect metal wires between the wiring layer and the lead frame to form a complete circuit connection;

[0036] Pot the installation chamber to form a second sealing layer, so as to jointly form the sealing layer of the intelligent power module with the first sealing layer, wherein the hardness of the second sealing layer is lower than that of the first sealing layer material.

[0037] The intelligent power module of the present invention adopts an integral lead frame. Pins are arranged on both sides of the lead frame, and the pins are connected to the frame body. Moreover, the wiring layer of the circuit board and the frame body are connected by means of metal wires. Therefore, during the manufacturing process of the IPM module, it is not necessary to provide a supporting force for the circuit board on which all the circuit components are installed in a single position in the encapsulation mold during the injection molding process as in the prior art. Instead, the lead frame and the circuit board are connected by means of metal wires. This avoids the phenomenon that during the injection molding process in the prior art, due to the injection of injection molding materials such as liquid resin, pressure is generated on the circuit board, resulting in stress between the pins and the circuit board, and causing delamination of the insulating layer medium of the circuit board, ultimately leading to the failure of the entire IPM module manufacturing and a reduction in the manufacturing yield. Therefore, the IPM module based on the structure of the lead frame in the embodiments of the present invention avoids the above problems during the injection molding process and effectively improves the manufacturing yield of the IPM module. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of the lead frame according to an embodiment of the present invention;

[0039] Figure 2 is a perspective structural diagram of a semi-finished product after the first injection molding of the lead frame according to an embodiment of the present invention;

[0040] Figure 3 is a schematic structural diagram of the formed IPM module according to an embodiment of the present invention;

[0041] Figure 4 is a perspective structural diagram of the IPM module according to an embodiment of the present invention;

[0042] Figure 5 is a sectional view of the IPM module according to an embodiment of the present invention;

[0043] Figure 6 is Figure 5 an enlarged view of A in

[0044] Figure 7 is a flowchart of the manufacturing method of the IPM module according to an embodiment of the present invention;

[0045] Figure 8 is another flowchart of the manufacturing method of the IPM module according to an embodiment of the present invention.

[0046] Reference Signs:

[0047] IPM module 100, pin 11, first sealing layer 12, step portion 121, step surface 1211, side wall 122, first demolding inclined surface 123, driving IC 13, circuit element 14, metal wire 15, circuit substrate 16, second demolding inclined surface 161, second sealing layer 17, adhesive portion 18, passive device 19, lead frame 20, mounting space 21, first connecting rib 22, electronic circuit 23, second connecting rib 24, frame body 25, pad 26. Detailed implementation mode

[0048] 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 according to examples.

[0049] The present invention provides an intelligent power module, as Figures 1 to 6 shown, including a lead frame 20, a circuit substrate 16, a circuit element 14 and a sealing layer. The lead frame 20 includes a frame body 25 and pins 11 arranged around the frame body 25. The frame body 25 is as Figure 1 shown by the annular area between the two dashed boxes in the figure. There is a mounting space 21 with a hollow center in the frame body 25. As Figure 1 shown, the lead frame 20 can be formed by etching or stamping copper material, and forms straight pins 11 extending outward on both sides of the frame body 25. These pins 11 are connected into a whole through the frame body 25. In Figure 1 the figure, the lead frame 20 is in the state before manufacturing the IPM module 100. The free ends of the pins 11 are connected to each other through the first connecting rib 22, and the connection parts of the pins 11 and the frame body 25 are connected to each other through the second connecting rib 24, so that the whole lead frame 20 forms a reliable whole. During the manufacturing process of the IPM module 100, the second connecting rib 24 will be cut off, and the free end parts of the pins 11 will be sheared to cut off the first connecting rib 22, and then shaped to form independent pins 11, as Figure 3 shown in the state of the pins 11 in the figure.

[0050] A wiring layer (not shown in the figure) is provided on the surface of the circuit board. The circuit board 16 is made of a metal material, such as a rectangular plate made of aluminum of materials like 1100 or 5052. Its thickness is much larger than that of other layers, generally ranging from 0.8 mm to 2 mm, and the commonly used thickness is 1.5 mm, mainly for heat conduction and heat dissipation. An insulating layer (not shown in the figure) is provided on the surface of the circuit board 16. Its thickness is relatively thinner than that of the circuit board 16, generally ranging from 50 μm to 150 μm, and the commonly used one is 110 μm. The wiring layer is composed of a metal such as copper and is insulated from the circuit board 16. The wiring layer includes circuit lines formed by etched copper foils. The thickness of the circuit line layer is also relatively thin, such as about 70 μm. The wiring layer also includes pads provided at the side positions close to the circuit board 16, and the above-mentioned wiring layer can be formed by using 2-ounce copper foil. Finally, a relatively thin solder mask layer can be coated on the wiring layer to play a role in circuit isolation and cut off the electrical connection between circuit lines. A plurality of circuit components 14 are provided on the wiring layer. The plurality of circuit components 14 or between the circuit components 14 and the wiring layer can be electrically connected by metal wires; the circuit components 14 can be fixed to the wiring layer by soldering.

[0051] The size of the circuit board 16 is adapted to the size of the mounting space 21 so as to be arranged in the mounting space 21 and electrically connected to the lead frame 20 through the metal wire 15, so as to realize the electrical connection between the wiring layer on the circuit board 16 and the pins 11. The sealing layer 12 at least wraps one surface of the circuit board 16 where the circuit components 14 are arranged, 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 the material can be resin.

[0052] Different from the prior art in which the pins 11 of the IPM module 100 are directly connected to the circuit board 16 by soldering, in the embodiment of the present invention, an integral lead frame 20 is formed. The pins 11 are arranged on both sides of the lead frame 20, and the pins 11 are connected to the frame body 25. And the wiring layer of the circuit board 16 and the frame body 25 are connected by means of connecting through the metal wire 15. Therefore, during the manufacturing process of the IPM module 100, it is not necessary to provide a supporting force for the circuit board 16 on which all the circuit components 14 are installed in the encapsulation mold as in the prior art during the injection molding process. Instead, the lead frame 20 is connected to the circuit board 16 by means of the metal wire 15. This avoids the phenomenon that during the injection molding process in the prior art, due to the injection of the injection molding material such as liquid resin, pressure is generated on the circuit board 16, resulting in stress between the pins 11 and the circuit board 16, and the dielectric layer of the insulating layer of the circuit board 16 is delaminated, ultimately causing the failure of the manufacturing of the entire IPM module 100 and reducing the manufacturing yield. Therefore, the structure of the IPM module 100 based on the lead frame 20 in the embodiment of the present invention avoids the above problems during the injection molding process and effectively improves the manufacturing yield of the IPM module 100.

[0053] In some embodiments of the present invention, an electronic circuit 23 is further disposed on the frame body 25, and a driving IC 13 (Integrated Circuit) and passive devices 19 electrically connected to the electronic circuit 23 are provided. As Figures 1 to 4 shown, the electronic circuit 23 is formed on the frame body 25. The electronic circuit 23 electrically connects the driving IC 13 and the passive devices 19 and is connected to each pin 11. The driving IC 13 is used to drive power switching transistors in the inverter circuit in the IPM module 100, such as MOS (metal oxide semiconductor) transistors or IGBTs (Insulated Gate Bipolar Transistors), etc. The passive devices 19 include electronic components such as resistors and capacitors. The driving IC 13, the passive devices 19, and the electronic circuit 23 together form a driving circuit of the inverter circuit to drive the inverter circuit to work. The current of the input and output signals of the driving circuit is much smaller than that of the inverter circuit, so it is easily interfered by the inverter circuit during the working process. Specifically, taking the switching transistor in the inverter circuit as an IGBT as an example, the driving IC 13 can be a half-bridge driving IC 13 (1 driving IC 13 drives 2 IGBTs, and a full-bridge IPM uses 3 half-bridge driving ICs 13), it can be an H-bridge driving IC 13 (1 driving IC 13 drives 4 IGBTs, and a single-phase IPM uses 1 H-bridge driving IC 13), it can be a 3 upper bridge + 3 lower bridge double driving IC 13 (1 3 upper bridge driving IC 13 drives 3 upper bridge IGBTs, 1 3 lower bridge driving IC 13 drives 3 lower bridge IGBTs, and a full-bridge IPM uses 1 set of 3 upper bridge + 3 lower bridge double driving ICs 13), it can be a full-bridge driving IC 13 (1 driving IC 13 drives 6 IGBTs, and a full-bridge IPM uses 1 full-bridge driving IC 13), it can be 3 single upper bridge + 1 3 lower bridge driving IC 13 (1 single upper bridge driving IC 13 drives 1 upper bridge IGBT, 1 3 lower bridge driving IC 13 drives 3 lower bridge IGBTs, and a full-bridge IPM uses 1 set of 3 single upper bridge + 1 3 lower bridge driving ICs 13).

[0054] By providing an inverter driving circuit formed by the driving IC 13, the passive devices 19, and the electronic circuit 23 on the frame body 25, different from the prior art where the driving IC 13 is disposed on the wiring layer of the circuit board 16 and the power switching transistors of the inverter circuit are all disposed on the same wiring layer, the interference caused by the working of the inverter circuit to the driving circuit is reduced, thereby effectively improving the working stability and reliability of the IPM module 100.

[0055] Specifically, in order to install the driving IC 13 and the passive device 19 on the frame body, a plurality of pads 26, i.e., copper foils, can be provided on the frame body 25, and the driving IC 13 and the passive device 19 are installed on the pads 26. Through a die bonding process, such as a silver glue curing process, silver glue can be dotted on the frame, and after the driving IC 13 and the passive device 19 are adhered, high-temperature baking and curing are performed to achieve electrical connection with the electronic circuit 23 after the silver glue melts and cures; or a solder chip process can be adopted, using solder paste, solder chips, solder wires, etc., to perform reflow soldering on the bonding components, i.e., the driving IC 13 and the passive device 19, on the frame to achieve electrical connection with the electronic circuit 23.

[0056] Moreover, the frame body 25 is formed with a bonding area by means of full electroplating or partial electroplating, etc. A plurality of bonding parts are provided on the bonding area, and the bonding area also realizes electrical connection between the driving circuit formed by the driving IC 13 and the passive device 19 and the wiring layer of the substrate through bonding wires. The bonding wires include gold wires, copper wires, gold-copper alloy wires, aluminum wires, aluminum-silicon wires, etc. In this way, the electronic circuit 23 and the wiring layer of the lead frame 20 form a complete circuit of the IPM module 100. The connection mode of the bonding wires can be that the bonding wires are connected by means of a bonding process.

[0057] By arranging the inverter driving circuit formed by the driving IC 13, the passive device 19, and the electronic circuit 23 on the frame body, compared with the prior art in which these components are arranged on the circuit board 16, while reducing the interference of the operation of the inverter circuit to the formed driving circuit, the area of the circuit board 16 is effectively reduced, thereby reducing the material cost of the entire IPM module 100.

[0058] In some embodiments of the present invention, the sealing layer includes a first sealing layer 12 and a second sealing layer 17. The first sealing layer 12 is provided on the part of the lead frame 20 except the installation vacancy 21, i.e., the part where the sealed frame body 25 is located. The surface of the lead frame 20 where the driving IC 13 and the passive device 19 are installed is located on the surface of the first sealing layer 12. The first sealing layer 12 is provided with upwardly protruding side walls 122 at the periphery. The side walls 122 and the lead frame 20 and the circuit board 16 form an installation chamber, and the second sealing layer 17 is provided in the installation chamber; the hardness of the second sealing layer 17 is lower than the hardness of the material of the first sealing layer 12. For example Figures 2 to 5As shown, the first sealing layer 12 seals a part of the frame body 25 and forms a laterally protruding side wall 122. The pins 11 pass through the first sealing layer 12 and extend outward. The second sealing layer 17 can be formed in the installation chamber by injection potting after the first sealing layer 12 is formed. The first sealing layer 12 is made of a high-hardness insulating material such as resin, which can be formed by injection molding using a mold. The second sealing layer 17 is made of a relatively low-hardness insulating material such as silica gel. The second sealing layer 17 covers the driving circuit part formed by the electronic circuit 23, the driving IC 13, and the passive devices 19 of the frame body 25, and at the same time covers the active devices such as power switching transistors on the electronic components of the circuit board 16. Since the second sealing layer 17 is formed in the installation chamber by a simple potting process after the first sealing layer 12 is formed, compared with the injection molding process in the prior art, taking the second sealing layer 17 made of silica gel as an example, the liquid silica gel falls into the installation chamber by natural gravity during potting. Compared with the injection molding material injected into the molding die under high pressure during injection molding, the stress of the silica gel on the circuit board 16 and the electronic circuit 23 during this process is much smaller than the stress generated by the injection molding material on the circuit board 16. Therefore, it effectively avoids the problem of the entire circuit being unreliable caused by the extrusion of this stress on the circuit components 14 and metal connection lines on the substrate and the electronic circuit 23, thereby further improving the product manufacturing yield.

[0059] In some embodiments of the present invention, as Figure 5 and Figure 6 shown, the sides of the sealing layer located on the sides of the pins 11 are inclined inward from the surface and bottom surface of the sealing layer respectively at the installation positions of the pins 11 to form a first demolding slope 123. The angle formed between the first demolding slope 123 and the vertical plane in the up and down direction is 2° to 9°, such as 3°, 4°, 5°, 6°, 8°. The first demolding slope 123 is located on the side of the first sealing layer 12. Taking the position of the pins 11 on the surface of the first sealing layer 17 as the demarcation line, two sub-slopes are formed upward and downward. These two sub-slopes are inclined inward from the position of the pins 11 and are formed in the mold cavity when the first sealing layer 12 is formed to facilitate demolding.

[0060] In some embodiments of the present invention, as Figure 5 and Figure 6 shown, the two side edges of the circuit board 16 close to the pins 11 are inclined outward from top to bottom to form a second demolding slope 161. By setting the second demolding slope inclined outward, during the manufacturing process of the IPM module 100, when the circuit board 16 is pasted to the first sealing layer 12, the glue coated at the contact between the bottom of the circuit board 16 and the first sealing layer 12 penetrates into the wiring layer on the surface of the circuit board 16 along the contact surface between the first sealing layer 12 and the circuit board 16, thereby contaminating the areas such as the pads 26 that need to be electrically connected on the circuit layer and causing unreliable subsequent soldering.

[0061] Further, the first sealing layer 12 is provided with a stepped portion 121, as Figure 5 and Figure 6 shown, the stepped portion 121 abuts against the edge of the surface of the circuit board 16. The stepped portion 121 connects to the contact surface of the second sealing layer 17 that contacts the second demolding inclined surface 161 of the aluminum substrate, wherein the stepped surface 1211 of the stepped portion 121 abuts against the edge of the surface of the circuit board 16, and the width of the stepped surface 1211 is between 1 mm and 2 mm, such as dimensions of 1 mm, 1.5 mm, 2 mm. The edge of the wiring layer is generally the process edge of the circuit board 16, that is, no wiring layer is provided on the surface of the process edge. By setting the appropriate width of the stepped surface 1211, when the circuit board 16 and the first sealing layer 12 are installed, it plays a role in positioning and supporting the circuit board 16.

[0062] In some embodiments of the present invention, as Figure 1 and Figure 2 shown, a plurality of lead frames 20 are arranged in parallel and connected to each other to form a frame assembly. In this embodiment, the plurality of lead frames 20 are sequentially connected to each other to form a frame assembly, as Figure 1 and Figure 2 in, it is a frame assembly composed of four lead frames 20, and it can also be a frame assembly composed of other numbers of lead frames 20 between 2 and 30. In this way, when manufacturing the IPM module 100, the frame assembly can be assembled at one time, and finally the IPM module 100 can be manufactured at one time, which can greatly improve the manufacturing speed and thus reduce the manufacturing cost of a single IPM module 100.

[0063] The present invention also proposes a manufacturing method of an IPM module based on the above embodiments, as Figure 7 shown, the manufacturing method includes the following steps:

[0064] Step S100: Place the lead frame in the frame forming die, and the pins of the lead frame protrude from both sides of the frame forming die;

[0065] Step S200: Inject plastic into the frame forming die to form a semi-finished product with a first sealing layer. The first sealing layer is provided on the remaining part of the frame body except for the installation vacancy, wherein the installation surface of the lead frame protrudes from the surface of the sealing layer, and the first sealing layer is provided with upwardly protruding side walls on the sides where the pins are located, and the pins protrude from both sides of the first sealing layer;

[0066] Step S300: Configure the circuit board and form a wiring layer on the surface of the circuit board;

[0067] Step S400: Dispose circuit elements at corresponding positions on the wiring layer;

[0068] Step S500, placing the semi-finished product and the circuit substrate configured with circuit elements in a fixture, wherein the circuit substrate is arranged in the installation space of the lead frame, and the side wall, the lead frame and the circuit substrate form an installation chamber;

[0069] Step S600, connecting metal wires between the wiring layer and the lead frame to form a complete circuit connection;

[0070] Step S700: Fill the installation cavity with glue to form a second sealing layer, which together with the first sealing layer forms a sealing layer of the IPM module, wherein the hardness of the second sealing layer is lower than that of the first sealing layer.

[0071] In step S100, Figure 1 and Figure 2 As shown, the lead frame 20 is installed in the frame molding die, and the pins 11 of the lead frame 20 are exposed from both sides of the frame molding die; wherein the pins 11 are straight, and the free ends of the pins 11 are connected by a first connecting rib 22, and the connection frame body 25 of the pins 11 is formed into a whole by a second connecting rib 24. Different from the prior art, the pins 11 need to be shaped to form bent legs before injection molding to facilitate placement in the injection mold. The lead frame 20 of the embodiment of the present invention does not need to be shaped, and only needs to be installed as a whole in the frame molding die, thereby eliminating the pin 11 molding step, saving the process, and improving production efficiency.

[0072] In step S200 , after the lead frame 20 is integrally installed in the frame molding die, injection molding is performed in the mold cavity of the frame molding die, that is, an insulating material such as a resin is injected, which has a greater hardness after the resin is cooled. Figure 2 This is a schematic diagram of the structure of the semi-finished product formed after injection molding. Figure 2 In the process, after injection molding and demoulding, a first sealing layer 12 is formed to seal the frame body 25 of the lead frame 20 except for the installation space 21, and further can be combined Figure 5 The first sealing layer 12 has a certain thickness, which seals part or all of the thickness of the lead frame 20, and extends toward the bottom of the lead frame 20 to form a certain thickness, and the upper surface of the lead frame 20 is exposed from the first sealing layer 12. In addition, a side wall 122 protruding upward is provided on the side where the pin 11 is located, and the side wall 122 has a certain wall thickness, such as 1mm to 2.5mm, such as 1mm, 1.5mm, 2mm, 2.5mm, so as to have a certain bearing strength. And the pin 11 is exposed from both sides of the first sealing layer 12.

[0073] Further, through the forming of the frame forming die, an inclined surface that slopes outward is formed on the wall surface of the mounting space 21 of the first sealing layer 12 on the side of the lead 11. The angle formed between this inclined surface and the vertical surface in the up and down direction is 4° to 10°, such as 3°, 4°, 5°, 6°, 8°, 9°. And a stepped portion 121 is formed between one side of the inclined surface and the side of the mounting lead frame 20 of the first sealing layer 12. The width of the stepped surface 1211 is between 1 mm and 2 mm, such as these dimensions of 1 mm, 1.5 mm, and 2 mm.

[0074] In steps S300 and S400, it is mainly the step of configuring the circuit board 16. First, a circuit board 16 with a suitable size is designed according to the required circuit layout. For example, for a general IPM module 100, 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 rotation 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.

[0075] Then, anti-corrosion treatment can be performed on both sides of the circuit board 16. For the IPM module 100 with a semi-encapsulation structure, the side of the circuit board 16 where no circuit components 14 are provided is exposed from the first sealing layer 12. At this time, anti-corrosion enhances its corrosion resistance during use and is not easily oxidized. For the IPM module 100 with a full-encapsulation structure, in order to save costs, anti-corrosion treatment may not be performed.

[0076] An insulating layer is provided on one side of the circuit board 16. Then, a copper foil is laminated on the surface of the insulating layer. Then, by etching the copper foil, the copper foil is partially removed to form a wiring layer. The wiring layer includes circuit lines and also includes pads provided at positions close to the side of the circuit board 16.

[0077] In step S500, the semi-finished product and the circuit board 16 configured with circuit components 14 are placed in a jig. The circuit board 16 is arranged in the mounting space 21 of the lead frame 20, and the side wall 122 and the lead frame 20 and the circuit board 16 form a mounting chamber. Since an inclined surface and a stepped portion 121 are also formed on the side of the mounting space 21 formed by the first sealing layer 12, the second demolding inclined surface 161 that expands outward on both sides of the circuit board 16 is matched with this inclined surface, and further, through the abutment of the edge of the surface of the circuit board 16 with the stepped surface 1211 of the stepped portion 121, good positioning of the circuit board 16 is formed to prevent the circuit board 16 from moving relatively after being installed in the mounting space 21.

[0078] Further, glue can also be applied between the bottom surface of the circuit board 16 and the first sealing layer 12 to form an adhesive part 18, further bonding and fixing the circuit board 16 and the first sealing layer 12 to achieve the fixation between the two.

[0079] In step S600, a metal wire 15 can be connected between the pads 26 of the wiring layer and the pads 26 of the lead frame 20 through a bonding process to form a complete circuit connection of the IPM module 100.

[0080] In step S700, the installation chamber is filled with glue to form a second sealing layer 17, which together with the first sealing layer 12 forms the sealing layer of the IPM module 100. The material for filling the glue can be an insulating material such as silicone rubber, which is formed through a simple injection process in the installation chamber. When filling the glue, the liquid silicone rubber falls into the installation chamber by natural gravity. Compared with the injection molding material injected into the molding die under high pressure, the stress of the silicone rubber on the circuit board 16 and the electronic circuit 23 is much smaller than the stress generated by the injection molding material on the circuit board 16. Therefore, it effectively avoids the problem of unreliable circuit connection caused by the extrusion of this stress on the circuit components 14 and metal connection wires on the substrate and the electronic circuit 23, thereby further improving the manufacturing yield of the product. The material of the silicone rubber is relatively soft, so the hardness of the second sealing layer 17 is lower than that of the sealing layer.

[0081] The product with the second sealing layer 17 formed after the above-mentioned glue filling is taken out from the tooling fixture, and the IPM module 100 is manufactured after the silicone rubber is cured.

[0082] Further, after the step of filling the installation chamber with glue, the manufacturing method further includes:

[0083] The exposed pins 11 are formed and electroplated to form a protective layer on the surface of the pins 11. Specifically, the first connecting rib 22 connecting the free ends of the pins 11 is cut off, and the second connecting rib 24 connecting the pins 11 near the first sealing layer 12 is cut off, and the pins 11 are formed, and the pins 11 are placed in an electroplating device for electroplating to form a protective layer on the surface of the exposed pins 11 to prevent corrosion and oxidation. Specifically, the protective layer can be a tin layer or a nickel-tin alloy layer, and the thickness of the alloy layer is generally 5μm.

[0084] Thus, the manufacturing of the IPM module 100 is completely completed.

[0085] The present invention also proposes a manufacturing method of an IPM module based on the above embodiments, as Figure 8 shown, the manufacturing method includes the following steps:

[0086] Step S100: Place the lead frame in the frame forming mold, with the pins of the lead frame protruding from both sides of the frame forming mold;

[0087] Step S200: Configure the circuit board and form a wiring layer on the surface of the circuit board;

[0088] Step S300: Place the circuit board in the mold cavity, where the circuit board is arranged in the mounting vacancy of the lead frame;

[0089] Step S400: Inject plastic into the frame forming mold to form a semi-finished product with a first sealing layer. The first sealing layer is arranged on the remaining part of the frame body except the mounting vacancy. The mounting surface of the lead frame protrudes from the surface of the sealing layer. The first sealing layer has a side wall protruding upward at the periphery. The pins protrude from both sides of the first sealing layer. The side wall and the lead frame as well as the circuit board form a mounting chamber;

[0090] Step S500: Arrange circuit components at corresponding positions on the wiring layer;

[0091] Step S600: Connect metal wires between the wiring layer and the lead frame to form a complete circuit connection;

[0092] Step S700: Fill the mounting chamber with glue to form a second sealing layer, so as to jointly form the sealing layer of the IPM module with the first sealing layer, where the hardness of the second sealing layer is lower than that of the material of the first sealing layer.

[0093] The difference from the manufacturing method of the IPM module 100 in the previous embodiment is that the installation of the circuit board 16 is not to install it into the mounting vacancy 21 and then perform subsequent glue filling to form the second sealing layer 17 after the first injection molding is completed to form the first sealing layer 12 of the semi-finished product. Instead, when the lead frame 20 is installed in the frame forming mold, the circuit board 16 is also fixed in the mounting vacancy 21 at the same time. Considering that the two side edges of the circuit board 16 are to be used as the inner wall surfaces of the mold cavity during injection molding, the structure of the frame forming mold at this time is different from that in the previous embodiment. The main difference is that the circuit board 16 is also fixed to the mold cavity at the same time, and the two side surfaces of the circuit board 16 serve as an inner wall surface of the mold cavity. In this way, after injection molding, the first sealing layer 12 is bonded and adhered to the side edges of the circuit board 16. Since the two are firmly bonded, the step of applying glue between the side edges of the circuit board 16 and the first sealing layer 12 in the previous embodiment can be further omitted to save the manufacturing process and reduce the manufacturing cost.

[0094] It should be noted that after the first sealing layer 12 is formed, such as Figure 5The bottom surface of the middle circuit board 16 is exposed to serve as a heat dissipation layer, so as to finally form a semi-encapsulated structure of the IPM module 100; alternatively, the circuit board 16 can be sealed in the first sealing layer 12 through different frame forming molds, so as to finally realize the fully encapsulated structure of the IPM module 100.

[0095] After demolding from the frame forming mold, silver paste can be applied to the surface of the wiring layer of the circuit board 16 through a silver paste curing process, and circuit devices such as power switching tubes can be installed and baked at a high temperature for curing, so as to realize electrical connection with the circuit layer after the silver paste melts and cures.

[0096] The step S600 of connecting the metal wire 15 between the wiring layer and the lead frame 20 to form a complete circuit connection is the same as that in the previous embodiment.

[0097] Thereafter, in step S700, the semi-finished product with the first sealing layer 12 formed and the circuit board 16 installed is installed in a tooling fixture, and the installation chamber is filled with glue to form the second sealing layer 17, so as to jointly form the sealing layer of the IPM module 100 with the first sealing layer 12. The step of filling glue to form the second sealing layer 17 is the same as that in the previous embodiment and will not be elaborated here.

[0098] Finally, the exposed pins 11 are formed and electroplated to form a protective layer on the surface of the pins 11, thus completing the manufacture of the IPM module 100 in its entirety.

[0099] 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.

[0100] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "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, and 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 to the present invention.

[0101] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0102] In the present invention, unless otherwise clearly defined and limited, terms such as "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 limited. 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.

[0103] In the present invention, unless otherwise clearly defined and limited, 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.

[0104] 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 limiting 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 lead frame, which includes a frame body and pins arranged around the frame body, and an empty mounting space is provided at the center of the frame body; A circuit board, on the surface of which a wiring layer is provided, and the circuit board is arranged in the mounting space and is electrically connected to the lead frame by metal wires; Circuit components, which are arranged on the wiring layer; A sealing layer, which at least wraps one side of the circuit board where the circuit components are arranged, and one end of the pin protrudes from the sealing layer; An electronic circuit is further configured on the frame body, and a driving IC and passive devices electrically connected to the electronic circuit are provided; A plurality of pads are provided on the frame body, and the driving IC and the passive devices are mounted on the pads; a bonding portion formed by a plurality of bonding areas is further provided on the frame body, and the wiring layer is electrically connected to the bonding portion by the metal wires; The sealing layer includes a first sealing layer and a second sealing layer connected to each other. The first sealing layer is arranged on the remaining part of the lead frame except the mounting space. The surface of the lead frame where the driving IC and the passive devices are mounted is located on the surface of the first sealing layer. The first sealing layer is provided with a side wall protruding upward at the periphery. The side wall and the lead frame and the circuit board form a mounting chamber, and the second sealing layer is arranged in the mounting chamber; the hardness of the second sealing layer is lower than that of the first sealing layer; The side surface of the sealing layer located at the pin inclines inward from the surface and the bottom surface of the sealing layer respectively at the position where the pin is mounted to form a first demolding slope, and the angle formed between the first demolding slope and the vertical surface in the up and down direction is 2° to 9°; the lead frame and the wiring layer are connected by a metal wire bonding process; The side edge of the circuit board near the pin inclines outward from top to bottom to form a second demolding slope, and the angle formed between the second demolding slope and the vertical surface in the up and down direction is 4° to 10°; the first sealing layer is provided with a step portion, and the step portion abuts against the edge of the surface of the circuit board; 2. The intelligent power module according to claim 1, wherein A plurality of the lead frames are arranged side by side and connected to each other to form a frame assembly.

3. A manufacturing method of the intelligent power module according to claim 1 or 2, characterized in that, Including the following steps: Placing the lead frame in a frame forming mold, and the pins of the lead frame protrude from both sides of the frame forming mold; Injecting the frame forming mold to form a semi-finished product with a first sealing layer, and the first sealing layer is arranged on the remaining part of the frame body except the mounting space, wherein the mounting surface of the lead frame protrudes from the surface of the sealing layer, and the first sealing layer is provided with a side wall protruding upward at the side where the pins are located, and the pins protrude from both sides of the first sealing layer; Configuring a circuit board and forming a wiring layer on the surface of the circuit board; Arranging circuit components at corresponding positions on the wiring layer; Placing the semi-finished product and the circuit board configured with circuit components in a tooling fixture, wherein the circuit board is arranged in the mounting space of the lead frame, and the side wall and the lead frame and the circuit board form a mounting chamber; Connect metal wires between the wiring layer and the lead frame to form a complete circuit connection; Inject glue into the installation chamber to form a second sealing layer, which together with the first sealing layer forms the sealing layer of the intelligent power module, wherein the hardness of the second sealing layer is lower than that of the first sealing layer material.

4. The manufacturing method according to claim 3, characterized in that, After the injection molding step, the manufacturing method further includes: Provide a plurality of pads on the surface of the frame body of the lead frame; Mount the replacement ICs and passive components on the pads.

5. A manufacturing method of the intelligent power module according to claim 1 or 2, characterized in that The method includes the following steps: Place the lead frame in a frame forming mold, and the pins of the lead frame protrude from both sides of the frame forming mold; Configure a circuit board and form a wiring layer on the surface of the circuit board; Place the circuit board in the mold cavity, wherein the circuit board is arranged in the installation space of the lead frame; Inject the frame forming mold to form a semi-finished product with a first sealing layer. The first sealing layer is arranged on the remaining part of the frame body except the installation space. The installation surface of the lead frame protrudes from the surface of the sealing layer. The first sealing layer is provided with upward protruding side walls at the periphery. The pins protrude from both sides of the first sealing layer. The side walls and the lead frame and the circuit board form an installation chamber; Arrange circuit elements at corresponding positions on the wiring layer; Connect metal wires between the wiring layer and the lead frame to form a complete circuit connection; Inject glue into the installation chamber to form a second sealing layer, which together with the first sealing layer forms the sealing layer of the intelligent power module, wherein the hardness of the second sealing layer is lower than that of the first sealing layer material.

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