High-power-density, low-resistance and low-inductance plastic package full-bridge power module and preparation method thereof

Abstract

The application discloses a high-power-density, low-resistance and low-inductance plastic-sealed full-bridge power module and a preparation method thereof. The module comprises a heat dissipation bottom plate, a TLP connecting layer, a ceramic copper-clad plate, a silver film, a chip, a bonding wire, a first soldering sheet, a copper bridge, a second soldering sheet, a copper column, an epoxy plastic sealing body, a signal pin, an AC terminal and DC positive and negative terminals. The upper surface of the heat dissipation bottom plate is sintered and connected with the lower copper layer of the ceramic copper-clad plate through the TLP connecting layer, and the chip is sintered and connected with the upper copper layer of the ceramic copper-clad plate through the silver film. The surface Gate area of the chip is electrically interconnected with the upper copper layer of the ceramic copper-clad plate through the bonding wire, and the surface Source area of the chip is reflow soldered with the copper bridge through the first soldering sheet. The application aims to overcome the defects of the prior art, provide a high-power-density, low-resistance and low-inductance plastic-sealed full-bridge power module and a preparation method thereof, and realize the improvement of power density, the reduction of parasitic inductance, the optimization of thermal resistance and the enhancement of process reliability.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a high power density, low parasitic inductance, and low thermal resistance plastic-encapsulated full-bridge power module and its fabrication method, suitable for new energy vehicles, industrial drives, new energy power generation and other fields. Background Technology

[0002] As power electronic systems evolve towards higher frequencies, higher efficiency, and higher power density, traditional wire-bonded power modules (such as standard IGBT modules) and semi-encapsulated HPD modules are increasingly unable to meet the demands. Existing modules generally suffer from drawbacks such as large size, low power density, high parasitic inductance, long heat dissipation paths, complex manufacturing processes, and insufficient reliability. 1. Limited power density: Traditional structures are not optimized for the miniaturization characteristics of SiC chips, resulting in a larger size; 2. High parasitic inductance: The power circuit is planar and has a long path, so the parasitic inductance is usually greater than 22nH, which can easily cause voltage overshoot and electromagnetic interference. 3. Poor heat dissipation performance: Heat needs to be transferred through multiple layers such as ceramic substrate, solder layer and copper base plate, resulting in thermal resistance accumulation and limiting long-term current carrying capacity; 4. Low process reliability: The substrate is prone to oxidation, multiple heating steps lead to thermal stress accumulation, and voids and failures are likely to occur at the interface. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high power density, low resistance and low inductance plastic-encapsulated full-bridge power module and its fabrication method, thereby achieving improved power density, reduced parasitic inductance, optimized thermal resistance and enhanced process reliability.

[0004] To achieve the above objectives, this invention provides a high power density, low impedance, and low inductance molded full-bridge power module, comprising a heat sink, a TLP connection layer, a ceramic copper-clad laminate, a silver film, a chip, bonding wires, a first solder pad, a copper bridge, a second solder pad, copper pillars, an epoxy molding compound, signal pins, AC terminals, and DC positive and negative terminals, wherein: The upper surface of the heat dissipation base plate is sintered and connected to the lower copper layer of the ceramic copper-clad laminate through the TLP connection layer, and the chip is sintered and connected to the upper copper layer of the ceramic copper-clad laminate through a silver film. The surface Gate area of ​​the chip is electrically interconnected with the upper copper layer of the ceramic copper-clad laminate through the bonding wire, and the surface Source area of ​​the chip is reflow soldered to the copper bridge through the first solder pad; The lower surface of the copper pillar is reflow soldered to the upper copper layer of the ceramic copper-clad laminate via a second solder pad. The signal pin is connected to the upper surface of the copper pillar. The AC terminal and the DC positive and negative terminals are both connected to the upper copper layer of the ceramic copper-clad laminate. The ceramic copper-clad laminate, silver film, chip, bonding wire, first solder pad, copper bridge, second solder pad, and copper pillar are all pressure-injected and encapsulated by the epoxy molding compound.

[0005] As a further preferred technical solution to the above technical solution, a laser welding device is used to weld the AC terminals and DC positive and negative terminals to the hollow area of ​​the upper copper layer of the ceramic copper-clad laminate; an ultrasonic welding device is used to weld the signal pin to the hollow area on the upper surface of the copper pillar.

[0006] This invention provides a method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module, comprising the following steps: Step 1: The chip and silver film are thermally bonded to the upper copper layer of the ceramic copper-clad laminate; Step 2: The semi-finished product formed in Step 1 is sintered and interconnected using a pressure sintering machine; Step 3: The first and second solder pads are mounted on the surface source area of ​​the chip and the upper copper layer of the ceramic copper-clad laminate using a pick-and-place machine. Then, copper bridges and copper pillars are mounted on the first and second solder pads respectively, and the copper bridges and copper pillars are fixed by a fixture. Step 4: Reflow soldering the material from Step 3 using a vacuum reflow oven; Step 5: Using bonding wires and bonding equipment, electrically interconnect the surface gate area of ​​the chip and the upper copper layer of the ceramic copper-clad laminate; Step Six: Use epoxy resin to encapsulate the semi-finished product formed in Step Five using a pressure injection molding machine; Step 7: Place the semi-finished product formed in Step 6 into an oven for curing for a preset time; Step 8: The solidified semi-finished product is then subjected to oxidation-reduction in a formic acid furnace; Step 9: Print the TLP bonding layer on the lower copper layer of the ceramic copper-clad laminate from Step 8; Step 10: Place the semi-finished product formed in Step 9 into an oven and bake it; Step 11: Place the semi-finished product formed in Step 10 onto the upper surface of the heat dissipation base plate using tooling; Step 12: The semi-finished product formed in Step 11 is sintered systematically using a pressure sintering machine; Step 13: Weld the signal needle to the upper surface of the copper pillar from Step 12 using an ultrasonic welding device; Step Fourteen: Use laser welding equipment to weld the AC terminals and DC positive and negative terminals to the cutout area of ​​the upper copper layer of the ceramic copper-clad laminate.

[0007] As a further preferred technical solution of the above technical solution, for the hot bonding in step one: using a chip bonding device, heating the metal nozzle of the device to a preset temperature, using the nozzle to pick up the chip, using the chip to cut the silver film so that a silver film of a preset thickness is attached to the bottom of the chip, and applying pressure through the device to bond the chip and the silver film to the upper copper layer of the ceramic copper-clad laminate. For step two sintering: A Teflon film of a preset thickness is laid on the surface of the semi-finished product formed in step one. First, the first semi-finished product is placed on a preheating platform and protected by nitrogen gas. Then, the first semi-finished product is placed on a heating platform and a preset pressure is applied to the chip surface using a pressure sintering device. Finally, it is placed on a cooling platform to cool, so that the chip, silver film and upper copper layer of the ceramic copper-clad laminate are interconnected. For step three, surface mounting: Using a surface mounting device, firstly, a plastic suction nozzle is used to vacuum the first and second solder pads respectively. After suction, alcohol is sprayed under the solder pads. Then, the first and second solder pads are mounted on the surface source area of ​​the chip and the upper copper layer soldering area of ​​the ceramic copper-clad laminate respectively. Finally, a suction nozzle is used to vacuum the copper bridge and copper pillar respectively and mount them on the surface source area of ​​the chip and the upper copper layer soldering area of ​​the ceramic copper-clad laminate. The copper bridge and copper pillar are fixed and limited by a tooling fixture.

[0008] As a further preferred technical solution of the above technical solution, for the formic acid furnace reflow soldering in step four: First, the semi-finished product from step three is placed on the preheating platform for preheating, and the chamber is filled with nitrogen for protection. Then, the semi-finished product is transferred to the welding platform. The chamber is first evacuated to 0 mbar, then filled with formic acid, and then filled with nitrogen. After maintaining the preset time, the chamber is evacuated to 0 mbar. After maintaining the preset time, the chamber is filled with nitrogen. Finally, the semi-finished product is transferred to the cooling platform to cool down to the preset temperature. For step five, bonding: using bonding equipment, the surface gate area of ​​the chip and the upper copper layer of the ceramic copper-clad board are connected by ultrasonic welding to achieve signal connection; the semi-finished product from step five is placed in a plasma cleaning equipment, argon gas is injected, and argon ions are generated at a preset power to bombard the material surface for a preset time to remove organic contaminants, oil or grease from the material surface. For step six, injection molding: First, place the semi-finished product from step six on the preheating platform, then place it into the injection mold, add epoxy resin cake, and finally close the mold, apply injection pressure and injection time, and inject the epoxy resin cake from solid to molten liquid through the mold injection port into the mold, ultimately achieving epoxy encapsulation of the exposed device.

[0009] As a further preferred technical solution to the above technical solution, for the curing of step seven: the semi-finished product of step seven is placed in an oxygen-free oven for curing, so that the cross-linking reaction of epoxy resin is more complete. For the oxidation-reduction process in step eight: the semi-finished product from step eight is placed on a pallet and fed into the formic acid furnace via a conveyor belt. The platform is set to the heating temperature. The chamber is first filled with nitrogen for protection, then evacuated to 0 mbar, then filled with formic acid gas. After maintaining the preset time, the vacuum is evacuated to 0 mbar, then filled with nitrogen gas, and finally the semi-finished product is transferred to the cooling platform to cool down to the preset temperature. For step nine printing: apply the TLP bonding layer of TLP material to the surface of the stencil and stir evenly. Transfer the semi-finished product from step eight to the stencil opening window through a tray. After setting the squeegee of the printing equipment, use the preset printing speed to print the TLP material onto the lower copper layer of the ceramic copper-clad laminate.

[0010] As a further preferred technical solution of the above technical solution, for the baking of step ten: after the oven is purged with nitrogen to ensure that the oxygen content is less than the preset value, the semi-finished product of step nine is placed in the oven, and then cooled to room temperature and the semi-finished product is taken out. For step eleven, placement, and step twelve, system sintering: place the heat sink base plate on the sintering carrier, then install the limiting fixture, and then attach the semi-finished product from step ten to the heat sink base plate; finally, transport the sintering carrier to the sintering platform via a conveyor belt, set the heating temperature on the sintering platform, and apply sintering pressure to the epoxy encapsulation surface with the sintering head for a duration that allows the upper surface of the heat sink base plate, the TLP connecting layer, and the lower copper layer of the ceramic copper-clad laminate to form an IMC layer through interatomic diffusion; For step thirteen, ultrasonic welding: the semi-finished product from step twelfth is fixed using a tooling fixture, and the signal needle is welded to the hollow area on the upper surface of the copper pillar using ultrasonic welding equipment. For step fourteen, laser welding: Use laser welding equipment to weld the AC terminals and DC positive and negative terminals to the cutout area of ​​the upper copper layer of the ceramic copper-clad laminate.

[0011] The beneficial effects of this invention are as follows: 1. Structural aspects: miniaturization and high power density; 2. Electrical performance: Laser-welded integrated busbars, with extremely low parasitic inductance and high frequency efficiency; 3. Heat dissipation capability: low thermal resistance, high current carrying capacity, and long lifespan; 4. Manufacturing process: high integration and high interface reliability. Attached Figure Description

[0012] Figure 1 This is an exploded view of the power module of the present invention.

[0013] Figure 2 These are front and back schematic diagrams of the power module of the present invention.

[0014] Figure 3 This is a side view of the power module of the present invention.

[0015] Figure 4 This is a schematic diagram of the preparation method of the present invention.

[0016] The reference numerals in the attached diagram include: 1. Heat sink base plate; 2. TLP connection layer; 3. Ceramic copper-clad laminate; 4. Silver film; 5. Chip; 6. Bonding wire; 7. First solder pad; 8. Copper bridge; 9. Second solder pad; 10. Copper pillar; 11. Epoxy encapsulation; 12. Signal pin; 13. AC terminal; 14. DC positive and negative terminals; 15. Hollowed-out area of ​​the upper copper layer; 16. Hollowed-out area of ​​the upper surface. Detailed Implementation

[0017] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0018] In the preferred embodiments of the present invention, those skilled in the art should note that the TLP materials and the like involved in the present invention can be considered as prior art.

[0019] Preferred embodiment.

[0020] like Figure 1-3 As shown, this invention discloses a high power density, low resistance, and low inductance molded full-bridge power module, including a heat dissipation base plate 1, a TLP connection layer 2 (TLP material refers to a Cu-Sn composite material that can be used as a sintering connection material), a ceramic copper-clad laminate 3, a silver film 4, a (power) chip 5, bonding wires 6, a first solder pad 7, a copper bridge 8, a second solder pad 9, copper pillars 10, an epoxy molding compound 11, signal pins 12, AC terminals 13, and DC positive and negative terminals 14, wherein: The upper surface of the heat dissipation base plate 1 is sintered and connected to the lower copper layer of the ceramic copper-clad laminate 3 through the TLP connecting layer 2, and the chip 5 is sintered and connected to the upper copper layer of the ceramic copper-clad laminate 3 through the silver film 4. The surface Gate area of ​​the chip 5 is electrically interconnected with the upper copper layer of the ceramic copper-clad laminate 3 through the bonding line 6, and the surface Source area of ​​the chip 5 is reflow soldered to the copper bridge 8 through the first solder pad 7. The lower surface of the copper pillar 10 is reflow soldered to the upper copper layer of the ceramic copper-clad laminate 3 via the second solder pad 9. The signal pin 12 is connected to the upper surface of the copper pillar 10. The AC terminal 13 and the DC positive and negative terminals 14 are both connected to the upper copper layer of the ceramic copper-clad laminate 3. The ceramic copper-clad laminate 3, silver film 4, chip 5, bonding wire 6, first solder pad 7, copper bridge 8, second solder pad 9, and copper pillar 10 are all pressure-injected and encapsulated by the epoxy molding compound 11.

[0021] Specifically, the AC terminal 13 and the DC positive and negative terminals 14 are welded to the hollow area 15 of the upper copper layer of the ceramic copper-clad plate 3 using laser welding equipment; the signal pin 12 is welded to the hollow area 16 on the upper surface of the copper pillar 10 using ultrasonic welding equipment.

[0022] like Figure 4 As shown, this invention also discloses a method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module, comprising the following steps: Step 1: The chip 5 and silver film 4 are attached to the upper copper layer of the ceramic copper-clad laminate 3 by heat bonding. Step 2: The semi-finished product formed in Step 1 is sintered and interconnected using a pressure sintering machine; Step 3: The first solder pad 7 and the second solder pad 9 are mounted on the surface source area of ​​the chip 5 and the upper copper layer of the ceramic copper-clad laminate 3 using a pick-and-place machine. Then, the copper bridge 8 and the copper pillar 10 are mounted on the first solder pad 7 and the second solder pad 9 respectively. The copper bridge 8 and the copper pillar 10 are fixed by a fixture. Step 4: Reflow soldering the material from Step 3 using a vacuum reflow oven; Step 5: Using (aluminum) bonding wire 6, an electrical interconnect is achieved between the surface gate area of ​​chip 5 and the upper copper layer of ceramic copper-clad laminate 3 through a bonding device; Step Six: Use epoxy resin to encapsulate the semi-finished product formed in Step Five using a pressure injection molding machine; Step 7: Place the semi-finished product formed in Step 6 into an oven for curing for a preset time (6 hours). Step 8: The solidified semi-finished product is then subjected to oxidation-reduction in a formic acid furnace; Step 9: Print TLP bonding layer 2 on the lower copper layer of the ceramic copper-clad laminate 3 from step 8; Step 10: Place the semi-finished product formed in Step 9 into an oven and bake it; Step 11: Place the semi-finished product formed in Step 10 onto the upper surface of the heat dissipation base plate 1 using tooling; Step 12: The semi-finished product formed in Step 11 is sintered systematically using a pressure sintering machine; Step 13: Weld the signal needle 12 to the upper surface of the copper pillar 10 in step 12 using an ultrasonic welding device; Step Fourteen: Use laser welding equipment to weld AC terminal 13 and DC positive and negative terminals 14 to the cutout area 15 of the upper copper layer of the ceramic copper-clad board 3.

[0023] Specifically, for the hot bonding in step one: using a chip bonding device, heat the metal nozzle of the device to a preset temperature (160 degrees Celsius), use the nozzle to pick up the chip 5, use the chip 5 to cut the silver film 4, so that a silver film 4 of a preset thickness (65um thickness) is attached to the bottom of the chip 5, and apply pressure (100N) through the device to bond the chip 5 and the silver film 4 to the upper copper layer of the ceramic copper-clad laminate 3. For step two sintering: A Teflon film of a preset thickness (120 micrometers) is laid on the surface of the semi-finished product formed in step one. First, the first semi-finished product is placed on a preheating platform (150 degrees Celsius) for 3 minutes, and nitrogen gas is used to protect the product. Then, the first semi-finished product is placed on a heating platform (250 degrees Celsius), and a preset pressure (14 MPa, 4 minutes) is applied to the surface of chip 5 using a pressure sintering device. Finally, it is placed on a cooling platform (18 degrees Celsius) for cooling (4 minutes) to interconnect chip 5, silver film 4 and upper copper layer of ceramic copper-clad laminate 3. For step three, surface mounting: Using a surface mounting device, firstly, a plastic suction nozzle is used to vacuum the first solder pad 7 and the second solder pad 9 respectively. After vacuuming, alcohol is sprayed under the solder pads. Then, the first solder pad 7 and the second solder pad 9 are mounted on the surface source area of ​​the chip 5 and the upper copper layer soldering area of ​​the ceramic copper-clad laminate 3 respectively. Finally, a suction nozzle is used to vacuum the copper bridge 8 and the copper pillar 10 respectively and mount them on the surface source area of ​​the chip 5 and the upper copper layer soldering area of ​​the ceramic copper-clad laminate 3. The copper bridge 8 and the copper pillar 10 are fixed and limited by a tooling fixture.

[0024] More specifically, for step four, the formic acid furnace reflow soldering: First, the semi-finished product from step three is placed on a preheating platform (200 degrees Celsius) for preheating (2 minutes), and the chamber is filled with nitrogen for protection. Then, the semi-finished product is transferred to a welding platform (250 degrees Celsius). The chamber is first evacuated to 0 mbar, then filled with formic acid (800 mbar), and then filled with nitrogen (to 1000 mbar). After maintaining this for a preset time (90 seconds), the chamber is evacuated to 0 mbar and maintained for a preset time (60 seconds). Then, nitrogen is filled (to 1000 mbar). Finally, the semi-finished product is transferred to a cooling platform to cool down to a preset temperature (40 degrees Celsius). For the bonding in step five: using bonding equipment, the surface gate area of ​​chip 5 and the upper copper layer of ceramic copper-clad board 3 are connected by ultrasonic welding (8mil aluminum) bonding wire 6 to achieve signal connection; the semi-finished product in step five is placed in a plasma cleaning equipment, and argon gas is injected (10ml / min). Argon ions are generated at a preset power (350W) to bombard the material surface for a preset time (15 seconds) to remove organic contaminants, oil or grease from the material surface; For step six injection molding: First, place the semi-finished product from step six on a preheating platform at 150 degrees Celsius for 5 minutes, then place it in an injection mold at 175 degrees Celsius, add epoxy resin cake, and finally close the mold. Apply an injection pressure of 65 kg / cm² and an injection time of 32 seconds to turn the epoxy resin cake from solid to molten liquid and inject it into the mold through the injection port, ultimately achieving epoxy encapsulation 11 to wrap the exposed device.

[0025] Furthermore, for the curing of step seven: the semi-finished product of step seven is placed in an oxygen-free oven at (175 degrees Celsius) for curing (6 hours) to make the cross-linking reaction of epoxy resin more complete. For the oxidation-reduction process in step eight: The semi-finished product from step eight is placed on a pallet and fed into the formic acid furnace via a conveyor belt. The platform is set to a heating temperature (220°C). The chamber is first filled with nitrogen for protection, then evacuated to 0 mbar, followed by filling with (98% concentration) formic acid gas (to 800 mbar). After maintaining this for a preset time (15 minutes), the vacuum is evacuated to 0 mbar, followed by filling with nitrogen gas (to 1000 mbar). Finally, the semi-finished product is transferred to a cooling platform to cool down to a preset temperature (40°C). For step nine printing: apply TLP material TLP bonding layer 2 to the stencil surface and stir evenly. Transfer the semi-finished product from step eight to the stencil opening window through the tray. After setting the squeegee of the printing equipment (6KG force), use the preset printing speed (20mm / s) to print the TLP material onto the lower copper layer of the ceramic copper-clad laminate 3.

[0026] Furthermore, for step ten, baking: the oven is purged with nitrogen to ensure that the oxygen content is less than the preset value (1000PPM). After the temperature is set (140 degrees Celsius), the semi-finished product from step nine is placed in the oven (20 minutes), and then cooled to room temperature before being removed. For step eleven placement and step twelve system sintering: place the heat dissipation base plate 1 on the sintering carrier, then install the limiting fixture, and then attach the semi-finished product from step ten to the heat dissipation base plate 1; finally, transport the sintering carrier to the sintering platform via a conveyor belt, set the heating temperature (230 degrees Celsius) on the sintering platform, and apply a sintering pressure (10 MPa) to the surface of the epoxy encapsulant 11 for a duration of 10 minutes, so that the upper surface of the heat dissipation base plate 1, the TLP connecting layer 2, and the lower copper layer of the ceramic copper-clad laminate 3 form an IMC layer through interatomic diffusion; For step thirteen, ultrasonic welding: the semi-finished product from step twelfth is fixed using a tooling fixture, and the signal pin 12 is welded to the hollow area 16 on the upper surface of the copper pillar 10 using ultrasonic welding equipment (with 220N pressure and 220W power). For step fourteen, laser welding: use laser welding equipment to weld AC terminal 13 and DC positive and negative terminals 14 to the cutout area 15 of the upper copper layer of ceramic copper-clad board 3.

[0027] Preferably, the present invention proposes a high power density, low thermal resistance, and low parasitic inductance molded full-bridge power module and its fabrication method, the core of which is: 1. Extremely high power density: Taking full account of the small area of ​​SiC chip 5, a new layout is designed for SiC chip 5, the module structure is extremely compact, reducing the module volume by more than 40% and greatly improving the power density. 2. Excellent electrical performance: The three-dimensional integrated power circuit greatly reduces the loop area. At the same time, the use of AMB and capacitor busbar laser welding technology greatly reduces loop inductance, effectively suppresses switching overvoltage and oscillation, and allows for higher switching frequency and system efficiency. 3. Superior heat dissipation performance: The direct sintering connection of "AMB-Pin-fin" creates an ultra-short, low-resistance thermal path, which significantly reduces the thermal resistance from the module junction to the bottom of the heat sink by up to 6%, improving long-term load capacity and reliability. 4. High process reliability and innovation: 4.1: The process sequence of "injection molding followed by reduction and then sintering" is a major innovation. It first uses the molding compound to protect all the delicate chip 5 and bonding structure, avoiding the possible thermal shock and contamination during the subsequent high-temperature sintering process. 4.2: Low-temperature formic acid reduction is specifically designed to address the oxidation problem on the back of AMB after injection molding. It efficiently cleans the interface at around 200℃, providing perfect conditions for the final "system sintering" and solving the risk of sintering voids and connection failures caused by the oxide layer in traditional processes. 4.3: The "system sintering" process completes the integration of the core composite substrate in one step, which simplifies the process and reduces the thermal stress and potential defects caused by multiple heating processes.

[0028] It is worth mentioning that the technical features such as TLP materials involved in this patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement methods of these technical features can be adopted using conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0029] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A high power density, low impedance, and low inductance molded full-bridge power module, characterized in that, Includes a heat sink base, TLP interconnect layer, chip, bonding wire, first solder pad, copper bridge, second solder pad, copper pillar, epoxy encapsulation, signal pins, AC terminals, and DC positive and negative terminals, among which: The upper surface of the heat dissipation base plate is sintered and connected to the lower copper layer of the ceramic copper-clad laminate through the TLP connection layer, and the chip is sintered and connected to the upper copper layer of the ceramic copper-clad laminate through a silver film. The surface gate area of ​​the chip is electrically interconnected with the upper copper layer of the ceramic copper-clad laminate through the bonding wire, and the surface source area of ​​the chip is reflow soldered to the copper bridge through the first solder pad; The lower surface of the copper pillar is reflow soldered to the upper copper layer of the ceramic copper-clad laminate via a second solder pad. The signal pin is connected to the upper surface of the copper pillar. The AC terminal and the DC positive and negative terminals are both connected to the upper copper layer of the ceramic copper-clad laminate. The ceramic copper-clad laminate, silver film, chip, bonding wire, first solder pad, copper bridge, second solder pad, and copper pillar are all pressure-injected and encapsulated by the epoxy molding compound.

2. The high power density, low impedance, and low inductance molded full-bridge power module according to claim 1, characterized in that, The AC terminals and DC positive and negative terminals are welded to the hollowed-out area of ​​the upper copper layer of the ceramic copper-clad laminate using laser welding equipment; the signal pins are welded to the hollowed-out area on the upper surface of the copper pillar using ultrasonic welding equipment.

3. A method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module, applicable to the high power density, low impedance, and low inductance molded full-bridge power module as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: The chip and silver film are thermally bonded to the upper copper layer of the ceramic copper-clad laminate; Step 2: The semi-finished product formed in Step 1 is sintered and interconnected using a pressure sintering machine; Step 3: The first and second solder pads are mounted on the surface source area of ​​the chip and the upper copper layer of the ceramic copper-clad laminate using a pick-and-place machine. Then, copper bridges and copper pillars are mounted on the first and second solder pads respectively, and the copper bridges and copper pillars are fixed by a fixture. Step 4: Reflow soldering the material from Step 3 using a vacuum reflow oven; Step 5: Using bonding wires and bonding equipment, electrically interconnect the surface gate area of ​​the chip and the upper copper layer of the ceramic copper-clad laminate; Step Six: Use epoxy resin to encapsulate the semi-finished product formed in Step Five using a pressure injection molding machine; Step 7: Place the semi-finished product formed in Step 6 into an oven for curing at the preset time; Step 8: The solidified semi-finished product is then subjected to oxidation-reduction in a formic acid furnace; Step 9: Print the TLP bonding layer on the lower copper layer of the ceramic copper-clad laminate from Step 8; Step 10: Place the semi-finished product formed in step 9 into an oven and bake it; Step 11: Place the semi-finished product formed in Step 10 onto the upper surface of the heat dissipation base plate using tooling; Step 12: The semi-finished product formed in Step 11 is sintered systematically using a pressure sintering machine; Step 13: Weld the signal needle to the upper surface of the copper pillar from Step 12 using an ultrasonic welding device; Step Fourteen: Use laser welding equipment to weld the AC terminals and DC positive and negative terminals to the cutout area of ​​the upper copper layer of the ceramic copper-clad laminate.

4. The method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module according to claim 3, characterized in that, For step one, hot bonding: using a chip bonding device, heat the device's built-in metal nozzle to a preset temperature, use the nozzle to pick up the chip, use the chip to cut the silver film so that a silver film of a preset thickness is attached to the bottom of the chip, and apply pressure through the device to bond the chip and silver film to the upper copper layer of the ceramic copper-clad laminate. For step two sintering: A Teflon film of a preset thickness is laid on the surface of the semi-finished product formed in step one. First, the first semi-finished product is placed on a preheating platform and protected by nitrogen gas. Then, the first semi-finished product is placed on a heating platform and a preset pressure is applied to the chip surface using a pressure sintering device. Finally, it is placed on a cooling platform to cool, so that the chip, silver film and upper copper layer of the ceramic copper-clad laminate are interconnected. For step three, surface mounting: Using a surface mounting device, firstly, a plastic suction nozzle is used to vacuum the first and second solder pads respectively. After suction, alcohol is sprayed under the solder pads. Then, the first and second solder pads are mounted on the surface source area of ​​the chip and the upper copper layer soldering area of ​​the ceramic copper-clad laminate respectively. Finally, a suction nozzle is used to vacuum the copper bridge and copper pillar respectively and mount them on the surface source area of ​​the chip and the upper copper layer soldering area of ​​the ceramic copper-clad laminate. The copper bridge and copper pillar are fixed and limited by a tooling fixture.

5. The method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module according to claim 4, characterized in that, For step four, the formic acid furnace reflow soldering: First, place the semi-finished product from step three on the preheating platform for preheating, fill the chamber with nitrogen for protection, then transfer the semi-finished product to the welding platform, first evacuate the chamber to 0 mbar, then fill with formic acid, then fill with nitrogen, maintain for a preset time, then start evacuating to 0 mbar, maintain for a preset time, then fill with nitrogen, and finally transfer the semi-finished product to the cooling platform to cool down to the preset temperature. For step five, bonding: using bonding equipment, the surface gate area of ​​the chip and the upper copper layer of the ceramic copper-clad board are connected by ultrasonic welding to achieve signal connection; the semi-finished product from step five is placed in a plasma cleaning equipment, argon gas is injected, and argon ions are generated at a preset power to bombard the material surface for a preset time to remove organic contaminants, oil or grease from the material surface. For step six, injection molding: First, place the semi-finished product from step six on the preheating platform, then place it into the injection mold, add epoxy resin cake, and finally close the mold, apply injection pressure and injection time, and inject the epoxy resin cake from solid to molten liquid through the mold injection port into the mold, ultimately achieving epoxy encapsulation of the exposed device.

6. The method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module according to claim 5, characterized in that, For the curing in step seven: the semi-finished product from step seven is placed in an oxygen-free oven for curing to make the cross-linking reaction of the epoxy resin more complete. For the oxidation-reduction process in step eight: the semi-finished product from step eight is placed on a pallet and fed into the formic acid furnace via a conveyor belt. The platform is set to the heating temperature. The chamber is first filled with nitrogen for protection, then evacuated to 0 mbar, then filled with formic acid gas. After maintaining the preset time, the vacuum is evacuated to 0 mbar, then filled with nitrogen gas, and finally the semi-finished product is transferred to the cooling platform to cool down to the preset temperature. For step nine printing: apply the TLP material TLP bonding layer to the stencil surface and stir evenly. Transfer the semi-finished product from step eight to the stencil opening window through a tray. After setting the squeegee on the printing equipment, use the preset printing speed to print the TLP material onto the lower copper layer of the ceramic copper-clad laminate.

7. The method for fabricating a high power density, low impedance, and low inductance molded full-bridge power module according to claim 6, characterized in that, For step ten, baking: After purging the oven with nitrogen to ensure that the oxygen content is less than the preset value, place the semi-finished product from step nine in the oven, and then cool it down to room temperature before taking out the semi-finished product. For step eleven, placement, and step twelve, system sintering: place the heat sink base plate on the sintering carrier, then install the limiting fixture, and then attach the semi-finished product from step ten to the heat sink base plate; finally, transport the sintering carrier to the sintering platform via a conveyor belt, set the heating temperature on the sintering platform, and apply sintering pressure to the epoxy encapsulation surface with the sintering head for a duration that allows the upper surface of the heat sink base plate, the TLP connecting layer, and the lower copper layer of the ceramic copper-clad laminate to form an IMC layer through interatomic diffusion; For step thirteen, ultrasonic welding: the semi-finished product from step twelfth is fixed using a tooling fixture, and the signal needle is welded to the hollow area on the upper surface of the copper pillar using ultrasonic welding equipment. For step fourteen, laser welding: Use laser welding equipment to weld the AC terminals and DC positive and negative terminals to the cutout area of ​​the upper copper layer of the ceramic copper-clad laminate.

Images