Ceramic-substrate-free direct liquid cooling insulation packaging power module and preparation method thereof

Abstract

The invention discloses a ceramic-substrate-free direct liquid cooling insulation packaging power module and a preparation method thereof, and belongs to the technical field of power semiconductor packaging. The module comprises a semiconductor power chip, a metal block, a plurality of connecting layers, a plurality of metal structural members, an insulation sealing structure and a sealing liquid cooling device. An electrode on the lower surface of the chip is connected with a metal block through a first connecting layer, the metal block is in direct contact with insulating cooling liquid, efficient heat dissipation is achieved, meanwhile, the cooling liquid serves as an insulating medium, and the electrical insulating function is ensured; electrodes on the upper surface of the chip are respectively led out through leads and the second connecting layer; the insulation sealing structure wraps the chip and the internal connection area, thereby further guaranteeing the insulation and sealing performance of the module. A traditional ceramic substrate is abandoned, the structural design is combined with a liquid cooling system, the thermal resistance is remarkably reduced, the heat dissipation efficiency is improved, meanwhile, the problem of insulation failure caused by bubbles is avoided, and the device is suitable for high-power-density application scenes and has the advantages of being low in cost, high in reliability, easy to expand and the like.

Description

Technical Field

[0001] This invention belongs to the field of power semiconductor packaging technology, and specifically discloses a power module with direct liquid-cooled insulating packaging without a ceramic substrate and its preparation method. Background Technology

[0002] like Figure 1 As shown, in traditional IGBT and MOSFET power modules, the bottom surface of the chip is connected to the upper metal layer of a metal-ceramic substrate (most commonly DBC, Direct Bond Copper, and AMB, Active MetalBrazing) via soldering or sintering. Insulation is achieved through the ceramic layer in the metal-ceramic substrate, ensuring current flow through the power chip. The lower metal layer is then soldered to a liquid cooling heatsink. Heat generated by the chip must pass through multiple interfaces before being dissipated from the system by the heatsink. There is now a significant industry consensus that the metal-ceramic substrate accounts for a considerable proportion of the total thermal resistance of a power module.

[0003] There are currently various packaging structure design methods to reduce the thermal resistance of power modules.

[0004] For example, CN 110838480B proposes a double-sided heat dissipation packaging design that uses two DBCs to conduct heat from the top and bottom surfaces of the chip respectively. This type of double-sided heat dissipation packaging technology is difficult to implement, requires strict tolerance control, and has a low yield. Furthermore, the increased use of a metal-ceramic substrate increases packaging costs.

[0005] For example, CN 113838821A proposes a method for optimizing heat dissipation structure design. It optimizes the structure of the metal-ceramic substrate, with the lower copper layer directly contacting the coolant through a structured design. This reduces the ceramic substrate / heat sink interface layer in traditional packaging structures. This approach simplifies the packaging process and reduces thermal resistance. However, due to the significant asymmetry in the metal layer structure on both sides of the metal-ceramic substrate, it is difficult to implement in existing metal-ceramic substrates. Organic insulating materials are needed to replace ceramics to achieve both insulation and thermal conductivity. However, such materials cannot simultaneously achieve high thermal conductivity and insulation strength. Therefore, the practical application prospects of this approach are limited.

[0006] For example, CN 119181676A employs a direct liquid cooling technology without a ceramic substrate to achieve the most extreme cooling effect. The lower surface of the chip is directly connected to a copper block, making the copper block and the lower surface of the chip have the same potential, forming the drain. Electrodes are led out from the gate and source on the upper surface of the chip, respectively, and the drain of the copper block is led out through a metal structure. Insulation and extreme heat dissipation are achieved by completely immersing the copper block and the chip in insulating liquid. However, this structure has an inherent risk of insulation breakdown. Because the chip is thin, often less than 0.3mm, the insulation distance between the chip's source and drain is short, and insulation is only achieved by the insulating liquid. If air bubbles are mixed into the insulating liquid during actual operation, and if these bubbles happen to be near the chip, they may cause a short circuit, posing a safety hazard. Summary of the Invention

[0007] To address the aforementioned issues, this invention discloses a power module packaging structure that achieves both insulation and efficient heat dissipation without requiring a metal-ceramic substrate, relying solely on an insulating coolant. Taking a SiC MOSFET as an example, existing mature molding techniques are used to separate the upper and lower source and drain electrodes of the semiconductor chip. Then, one electrode (typically the drain) directly contacts the insulating coolant after being connected to a metal block. This packaging method significantly reduces the thermal resistance of the power module, lowers the chip's operating temperature, and improves energy conversion efficiency. Furthermore, by avoiding the use of a metal-ceramic substrate, packaging material costs are reduced, and this unique insulation design avoids safety issues similar to those caused by insulation breakdown failure in metal-ceramic substrates. Through structural design, this invention is applicable to various voltage levels.

[0008] The technical solution of the present invention is as follows: A power module with direct liquid-cooled insulating packaging without a ceramic substrate includes: A semiconductor power chip, the chip comprising a chip body, a first electrode located on the lower surface, and a second electrode and a third electrode located on the upper surface; Metal block; A first connection layer connects the first electrode of the chip to the metal block, such that the metal block and the first electrode form the same potential. First metal structural component; Lead wires connect the third electrode of the chip to the first metal structure for gate electrical lead-out; Second metal structural component; The second connection layer connects the second electrode of the chip to the second metal structure and is used for source electrical lead-out. Third metal structural component; The third connecting layer connects the metal block and the third metal structural component, and is used for drain electrical lead-out; An insulating and sealed structure covers the chip, the first connection layer, the leads, the second connection layer, the third connection layer, and a portion of each metal structural component; A sealed liquid cooling device is filled with insulating coolant, and the portion of the metal block not covered by the insulating sealing structure is in direct contact with the coolant.

[0009] Furthermore, in the aforementioned power module, the first electrode is the drain, the second electrode is the source, and the third electrode is the gate.

[0010] Furthermore, in the aforementioned power module, the metal block is made of copper, aluminum, molybdenum, or alloys thereof.

[0011] Furthermore, in the aforementioned power module, the first connection layer, the second connection layer, and the third connection layer are connection layers formed by sintering or welding techniques.

[0012] Furthermore, in the aforementioned power module, the leads are aluminum wires, and the connections are achieved through wire bonding.

[0013] Furthermore, in the aforementioned power module, the insulating and sealing structure is made of epoxy resin or silicone gel.

[0014] Furthermore, the aforementioned power module, the sealed liquid cooling device also includes additional sealing material to ensure that the coolant does not leak and to enhance the overall structural integrity.

[0015] This invention also discloses a method for preparing the above-mentioned power module, comprising the following steps: S1: Provide a metal block and print sintered silver paste at its predetermined position to form a prefabricated layer of the first bonding layer; S2: Place the semiconductor power chip on the prefabricated layer of the first connection layer and perform the first drying process; S3: Print sintered silver paste on the second electrode of the chip to form a prefabricated layer of the second connection layer, and perform a second drying process; S4: Position the first metal structural component, the second metal structural component, and the third metal structural component in predetermined positions using tooling; S5: Perform a pressure sintering process to simultaneously densify the first connecting layer, the second connecting layer, and the third connecting layer, forming a strong electrical connection; S6: The third electrode of the chip is connected to the first metal structure by wire bonding process; S7: Inject insulating and sealing material and cure it to form an insulating and sealing structure that covers the chip and its internal connection structure; S8: Place the package obtained in step S7 into a sealed liquid cooling device and fill it with insulating coolant.

[0016] Furthermore, in the above preparation method, the pressure sintering process parameters in step S5 are: upper mold temperature 240°C ~ 260°C, lower mold temperature 250°C ~ 270°C, pressure 20MPa ~ 30MPa, and holding time 250 seconds ~ 350 seconds; the curing conditions in step S7 are: temperature 140°C ~ 160°C, and time 1.5 hours ~ 2.5 hours.

[0017] This invention also discloses a power semiconductor half-bridge or full-bridge inverter module, comprising: Multiple power module units with direct liquid-cooled insulating packaging without ceramic substrates, as described above; The metal blocks of each power module unit are insulated from each other by the insulating sealing structure and the insulating coolant in the sealing liquid cooling device, together forming a half-bridge or full-bridge inverter circuit, forming a DC positive terminal DC+, a DC negative terminal DC- and an AC output potential region that are insulated from each other.

[0018] The present invention has the following beneficial effects: This invention employs an industry-standard method of organic insulation protection to achieve direct insulation between the upper and lower surfaces of the chip. Based on this, the lower surface of the chip is connected to a metal block, which is in direct contact with the coolant, achieving efficient liquid cooling.

[0019] As shown in the diagram. Figure 2 As shown, the 10-structure (currently the industry standard) ensures insulation between the source and drain of the SiC MOSFET chip, requiring current to flow through the internal 100-structure of the semiconductor chip. This avoids the risk of short-circuiting and conducting without passing through the internal 100-structure, as in CN 119181676A. In the 11-structure, sufficient insulation distance is required to overcome the risk of insulation breakdown. For the coolant, extreme process control to achieve a bubble-free solution is not necessary. This is more economical than CN119181676A. Because the use of a metal-ceramic substrate is avoided, the heat generated by the chip is directly liquid-cooled by a high-thermal-capacity metal block, further reducing the module's thermal resistance compared to designs like CN 113838821A. By avoiding the use of a metal-ceramic substrate and without introducing materials not part of existing processes, and considering that welding, sintering, and sealing are all standard industry techniques, this design reduces module material costs. Attached Figure Description

[0020] Figure 1 A schematic diagram of the packaging structure of a power module in the prior art; Figure 2A schematic diagram of the power module with direct liquid-cooled insulating packaging without ceramic substrate designed in this invention; Figure 3 In a variation of the present invention, when connecting gate levels, the 4 / 5 can also be connected by welding or sintering; Figure 4 Another variation of the invention contains 12 sealing materials.

[0021] Figure 5 Schematic diagrams of different sealing types in this technical field; Figure 6 Model 1: Simulation diagram of the fully welded model; Figure 7 Model 2: Simulation diagram of the fully sintered joint model; Figure 8 Model 3: Simulation diagram of sintering model without ceramic substrate; Component structure description in the diagram: 1- Semiconductor power chip: 100 is the chip body, the first electrode 101 is the lower surface electrode of the chip, usually the drain; the second electrode 102 and the third electrode 103 are the upper surface electrodes of the chip, 101 and 102 are the electrodes through which the current mainly flows, 102 is usually the source, and 103 is the gate. 2-First connection layer: This is the connection layer between the first electrode 101 of the chip and the metal block 3. As the first bonding layer, the industry currently typically uses welding or sintering technology to achieve the connection. 3-Metal block: This is a structural component that is connected to the first electrode 101 of the chip to form the same potential. It can be a common metal or alloy such as copper, aluminum, or molybdenum. 4- Leads: The lead connection between the third electrode 103 of the chip and the first metal structure 5. When connecting the gate level, wire bonding is usually used to connect the gate level. The lead is usually aluminum wire. 5-First metal structural component: Connects to the chip gate. Used for gate-level electrical leads. Typically made of copper; 6-Second connection layer: This is the connection layer between the second electrode 102 of the chip and the second metal structure 7. As the second bonding layer, the connection is usually achieved by welding or sintering technology in the industry. 7-Second metal structural component: The second electrode 102 (usually the source electrode) connects to the chip and is used for source-level electrical lead-out. It is usually made of copper. 8-Third connection layer: This is the connection layer between the metal block 3 and the third electrode 103 of the chip and the third metal structure 9. As the third bonding layer, welding or sintering technology is commonly used in the industry to achieve the connection. 9-Third metal structural component 9, used to connect metal block 3, essentially connects the first electrode 101 of the chip (usually the drain electrode), used for drain electrical lead-out, usually made of copper material; 10-Insulation and sealing structure: Uses industry-standard materials, such as epoxy resin and silicone gel; 11-Sealed liquid cooling device (heat sink): The coolant is located inside the sealed liquid cooling device 11 and is in direct contact with the metal block 3 to conduct heat generated by the semiconductor power chip 1. 12-Sealing material: Used to ensure the coolant does not leak and to enhance the overall structural integrity. If, in actual manufacturing, the structure containing 11 is not fully sealed, a step-by-step sealing method is used. When the sealed structure (covering all structures from 1 to 10) is connected to 11, structure 12 is used to prevent the coolant in 11 from overflowing and to ensure overall structural stability. Several sealing technologies are currently available, including silicone gel and liquid resin, all of which require a shell. Mold forming technology, on the other hand, does not require a shell. The difference is as follows... Figure 5 As shown. Detailed Implementation

[0022] The metal-ceramic substrate in the power module plays a crucial internal insulation role. The main principle is as follows: 1. The ceramic layer in a cermet substrate has high insulation strength. At a certain thickness, current cannot conduct between the copper layers on the upper and lower surfaces of the cermet substrate under a specific voltage. When ceramic insulation breakdown occurs, current flows through other conductors in the system and across the copper layers on the upper and lower surfaces of the cermet substrate. This results in the power module losing its power control capability and creates a safety hazard.

[0023] 2. The regions where the copper layers on the upper surface of the metal-ceramic substrate are connected have the same potential.

[0024] 3. The sealing material in the power module tightly covers the contact surfaces to achieve insulation. This ensures that current can only flow through the interior of the semiconductor chip between the upper and lower surfaces.

[0025] 4. Multiple insulated and independent regions can be formed between the upper surfaces of the metal-ceramic substrate by partially removing metal. These regions can be electrically connected using industry-standard wire bonding, welding, or sintering structural methods.

[0026] Firstly, this invention addresses the first principle by suggesting that it can be achieved through other insulation methods. For example... Figure 2 As shown, structure 3 is in contact with the insulating coolant in structure 11. The coolant helps to dissipate heat from structure 3 while also providing insulation.

[0027] Second: Regarding the second principle of this invention, the metal block of structure 3 is designed to be directly connected to the lower surface of the chip, ensuring that structure 3 and the electrode of chip 101 have the same potential. Therefore, multiple chips can be connected in parallel on the same metal block of structure 3 to increase the total current flowing through the semiconductor chip in the power module. Structures 4-9 are adjusted accordingly.

[0028] Third and fourth points: Regarding the third and fourth principles of this invention, the electrical properties of this solution can be changed through structural design.

[0029] If adopted Figure 2 As shown, if the main current flows through only one or more parallel semiconductor chips, it is a single-switch controlled power module. If a structure of multiple metal blocks 3 and chip 1 is used, three mutually insulated regions can be formed inside the power module through electrical design: DC input DC+, DC output DC-, and AC output AC. Structure 10 provides insulation on the upper surface of the chip. Sufficient insulation distance is designed in structure 11 to achieve insulation between the lower surfaces of the chip. The electrical characteristics of DC+, DC-, AC, and the gate control terminals are respectively led out in a manner similar to structures 4 to 9. At this point, a power semiconductor half-bridge or full-bridge inverter module can be designed. Different electrical functions can be achieved through similar structural variations.

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0031] like Figure 2 The power module shown is a direct liquid-cooled insulating package without a ceramic substrate, comprising: A semiconductor power chip 1, the chip 1 including a chip body 100, a first electrode 101 located on the lower surface, and a second electrode 102 and a third electrode 103 located on the upper surface; Metal block 3; The first connection layer 2 connects the first electrode 101 of the chip 1 to the metal block 3, so that the metal block 3 and the first electrode 101 form the same potential. First metal structural component 5; Lead 4 connects the third electrode 103 of the chip 1 to the first metal structure 5 and is used for gate electrical lead-out; Second metal structural component 7; The second connection layer 6 connects the second electrode 102 of the chip 1 to the second metal structure 7 and is used for source electrical lead-out. Third metal structural component 9; The third connecting layer 8 connects the metal block 3 and the third metal structural member 9, and is used for drain electrical lead-out; An insulating and sealing structure 10 covers a portion of the chip 1, the first connection layer 2, the lead wire 4, the second connection layer 6, the third connection layer 8, and the metal structural components 5, 7, and 9. The sealed liquid cooling device 11 is filled with insulating coolant, and the part of the metal block 3 not covered by the insulating sealing structure 10 is in direct contact with the coolant.

[0032] Preferably, the first electrode 101 is the drain, the second electrode 102 is the source, and the third electrode 103 is the gate.

[0033] Preferably, the metal block 3 is made of copper, aluminum, molybdenum, or alloys thereof.

[0034] Preferably, the first connecting layer 2, the second connecting layer 6, and the third connecting layer 8 are connecting layers formed by sintering or welding techniques.

[0035] Preferably, the lead 4 is an aluminum wire, and the connection is achieved by wire bonding.

[0036] Preferably, the material of the insulating sealing structure 10 is epoxy resin or silicone gel.

[0037] As a preferred option, such as Figure 3 As shown, in one form of structural modification of the present invention, when connecting gate levels, the 4 / 5 can also be connected by welding or sintering.

[0038] As a preferred option, such as Figure 4 As shown, the sealed liquid cooling device 11 also includes additional sealing material 12 to ensure that the coolant does not leak and to enhance the overall structural integrity. If, in actual processes, the structure containing the radiator 11 is not fully sealed for protection, a step-by-step approach is adopted. When the sealed structure (covering all structures from 1 to 10) is connected to the radiator 11, structure 12 is used to ensure that the coolant in 11 does not overflow and that the overall structure remains stable. Example

[0039] This embodiment discloses a method for fabricating the above-mentioned power module, including the following steps: S1: Provide a metal block 3 and print sintered silver paste at its predetermined position to form a prefabricated layer of the first connecting layer 2; S2: Place the semiconductor power chip 1 on the prefabricated layer of the first connection layer 2 and perform the first drying process; S3: Print sintered silver paste on the second electrode 102 of the chip 1 to form a pre-fabricated layer of the second connection layer 6, and perform a second drying process; S4: Position the first metal structural component 5, the second metal structural component 7, and the third metal structural component 9 in predetermined positions using tooling. S5: Perform a pressure sintering process to simultaneously densify the first connecting layer 2, the second connecting layer 6, and the third connecting layer 8 to form a strong electrical connection. S6: The third electrode 103 of the chip 1 is connected to the first metal structure 5 by wire bonding process using wire 4; S7: Inject insulating and sealing material and cure it to form an insulating and sealing structure 10 covering the chip 1 and the internal connection structure; S8: Place the package obtained in step S7 into the sealed liquid cooling device 11 and fill it with insulating coolant.

[0040] 9. The preparation method according to claim 8, characterized in that the pressure sintering process parameters in step S5 are: upper mold temperature 240°C ~ 260°C, lower mold temperature 250°C ~ 270°C, pressure 20MPa ~ 30MPa, and holding time 250 seconds ~ 350 seconds; the curing conditions in step S7 are: temperature 140°C ~ 160°C, and time 1.5 hours ~ 2.5 hours.

[0041] As a preferred option, the following is a specific preparation process: 1: Single-switch power control module Step 1. Using a T2 copper block with dimensions of 15mm x 15mm x 30mm, sintered silver paste is printed onto an 80µm thick steel mesh with 5.5mm x 5.5mm openings. Figure 2 The printing parameters for positions 2 and 8 in the middle structure are shown in Table 1 below: Table 1: Printing Parameters Printing press brand and model Erka, E4 Sintered silver brand and model Heraeus, ASP043 Printing times 1 time Printing rate 20mm / sec. scraper pressure 1.5Kg Silver paste application amount on scraper ≥1g / cm (corresponding to scraper length) Steel mesh demolding rate 0.5 mm / sec. After printing, the sintered silver was dried under a nitrogen atmosphere. The drying temperature was 120°C, and the drying time was 20 minutes. The thickness of the dried sintered silver was approximately 35 μm. Step 2. The SiC chip (structure 1), with dimensions of 5mm x 5mm x 0.2mm, is fixed to structure 2 using a heat-mounting device. The heat-mounting parameters are shown in Table 2 below. Table 2 Hot Post Parameters Pick and place machine brand and model BESI, Datacon2200EVO Pick and place machine chassis heating temperature 150°C Pick and place machine nozzle heating temperature 100°C suction pressure 4Kg nozzle application time 1 second. Step 3. Sintered silver is printed onto the 102 electrode on the upper surface of the chip using a stencil. The stencil opening size is smaller than the 102 electrode size. The stencil thickness remains 80µm. After drying, approximately 35µm thick sintered silver is obtained.

[0042] Step 4. Using the tooling, place structures 5, 7, and 9. Their relative positions are as follows: Figure 2 As shown.

[0043] Structures 1, 7, and 9 were subjected to pressure sintering. Using a specially designed pressure sintering mold, structures 1, 7, and 9 were pressurized and heated. The purpose was to induce a densification reaction in structures 2, 6, and 8, forming a tight bond. The sintering parameters are shown in Table 3 below. Table 3: Sintering Parameters Pick and place machine brand and model QUICK, YJ-S5000 Upper mold heating temperature 250°C Lower mold heating temperature 260°C Sintering pressure after mold closing 25Mpa Sintering pressure after mold closing 300 seconds. Step 6. Using ultrasonic wedge wire bonding technology, a 150µm diameter aluminum wire is connected between electrode 103 and structure 5. Wire bonding machine brand and model: K&S, Asterion 8000. Step 7. Embed the above structure into structure 11. Using potting technology, encapsulate the above structure with organic epoxy molding compound (3M DP420) to form structure 10. No special equipment is required. Drying and curing temperature and time: 150°C, 2 hours. Example

[0044] This example is a simulation test case. Experimental objective: This simulation aims to compare the steady-state chip junction temperature under high-power heating conditions between a typical heat dissipation structure of a traditional power module and the heat dissipation structure proposed in this invention. Two-dimensional simulation analysis is performed in Ansys to obtain temperature distribution information.

[0045] Source of experimental model This experiment focuses on the power module packaging widely used in the new energy vehicle industry. A 2D model was used to construct the main internal structure of the power module, and Ansys Workbench was used to perform finite element simulations to investigate the differences in chip junction temperature between different structures at the same power level. The main structure, from top to bottom, consists of the chip, chip interconnect layer, metal-ceramic substrate, metal-ceramic substrate interconnect layer, and heat sink.

[0046] Experimental methods Model 1 and Model 2 both use this typical packaging structure, while Model 3 is the power module structure model without a ceramic substrate according to this patent application (e.g., Figure 2 (Designed in China).

[0047] Model 1: Fully Welded Model Figure 6 Model 2: Fully Sintered Joint Model Figure 7 Model 3: Sintering model without ceramic substrate ( Figure 8 ).

[0048] The model parameters are shown in Table 4 below.

[0049] Table 4: Model Parameters Dimensions (mm) Thermal conductivity (W / (m⋅K)) SiC chip 5*0.3 200 SAC305 alloy under-chip interconnect layer 5*0.02 56 Sintered silver under the chip interconnect layer 5*0.02 260 DBC / AMB upper and lower copper layers 20*0.3 390 Al2O3 ceramics 21*0.32 24 Si3N4 ceramics 21*0.32 80 heat sink 25*3 0.3 Simulation Procedure: The same 1000W heat output was applied to the SiC chips in all three models. The bottom surface of the heatsink was designated as the sole heat dissipation channel and kept at a constant temperature (65 degrees Celsius). The heat exchange rates of the heatsinks were identical across all three models. All other structures in the model were configured as non-heat-dissipating. That is, the heat generated by the chip can only be dissipated through the chip interconnect material – copper-plated ceramic substrate – system-level interconnect material – heatsink. Given other packaging materials, the simulation model's settings closely approximate the actual operating conditions of the power module, providing both a realistic basis and theoretical support.

[0050] Results analysis: In Model 1, using a fully welded model with a DBC cermet substrate (which has poor heat dissipation), the chip's highest temperature reaches 278°C at steady state. In Model 2, using a fully sintered model with better heat dissipation and an AMB cermet substrate (which has even better heat dissipation), the chip's highest temperature is reduced to 188°C at steady state. Model 2 represents one of the best mass-production packaging forms in terms of heat dissipation currently available in the industry. In Model 3, after removing the cermet substrate, the chip's highest temperature further decreases to 159°C. This demonstrates that removing the cermet substrate allows for more effective heat removal from the SiC chip system.

[0051] Summary of Implementation Examples: Example 1 details the specific structure of the power module of the present invention, including the arrangement of the chip, metal block, various connection layers and metal structural components, as well as the combination of insulation sealing and liquid cooling system, clarifying the functions and electrical connections of each component. Example 2 provides the preparation method of the module, focusing on the pressure sintering process parameters (such as upper / lower mold temperature, pressure, and holding time) and curing conditions to ensure the dense and reliable connection layers; the specific implementation uses mature processes such as printing, surface mounting, sintering, bonding, and potting, possessing good operability and repeatability. Example 3, through simulation comparison, shows that the structure of the present invention (Model 3) significantly reduces the chip junction temperature (from 278°C and 188°C to 159°C) compared to traditional welding and sintering packaging methods (Models 1 and 2), verifying its excellent heat dissipation performance. In summary, the present invention, through structural innovation and process optimization, achieves efficient heat dissipation, high reliability, and low cost ceramic substrate-free power module packaging, suitable for high-power applications such as new energy vehicles and industrial frequency converters, and has broad industrialization prospects.

[0052] The embodiments described above are merely a limited number of preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A power module with direct liquid-cooled insulating packaging without a ceramic substrate, characterized in that, include: A semiconductor power chip (1) includes a chip body (100), a first electrode (101) located on the lower surface, and a second electrode (102) and a third electrode (103) located on the upper surface. Metal block (3); The first connection layer (2) connects the first electrode (101) of the chip (1) to the metal block (3), so that the metal block (3) and the first electrode (101) form the same potential; First metal structural component (5); Lead (4) connects the third electrode (103) of the chip (1) to the first metal structure (5) for gate electrical lead-out; Second metal structural component (7); The second connection layer (6) connects the second electrode (102) of the chip (1) to the second metal structure (7) for source electrical lead-out; Third metal structural component (9); The third connecting layer (8) connects the metal block (3) and the third metal structural member (9) for drain electrical lead-out; An insulating and sealing structure (10) covers a portion of the chip (1), the first connection layer (2), the lead wire (4), the second connection layer (6), the third connection layer (8), and each metal structural component (5, 7, 9). The sealed liquid cooling device (11) is filled with insulating coolant, and the part of the metal block (3) not covered by the insulating sealing structure (10) is in direct contact with the coolant.

2. The power module according to claim 1, characterized in that, The first electrode (101) is the drain, the second electrode (102) is the source, and the third electrode (103) is the gate.

3. The power module according to claim 1, characterized in that, The metal block (3) is made of copper, aluminum, molybdenum or alloys thereof.

4. The power module according to claim 1, characterized in that, The first connecting layer (2), the second connecting layer (6) and the third connecting layer (8) are connecting layers formed by sintering or welding technology.

5. The power module according to claim 1, characterized in that, The lead wire (4) is an aluminum wire and is connected by wire bonding.

6. The power module according to claim 1, characterized in that, The insulating and sealing structure (10) is made of epoxy resin or silicone gel.

7. The power module according to claim 1, characterized in that, The sealed liquid cooling device (11) also includes additional sealing material (12) to ensure that the coolant does not leak and to enhance the overall structural integrity.

8. A method for manufacturing a power module as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Provide a metal block (3) and print sintered silver paste at its predetermined position to form a prefabricated layer of the first connecting layer (2); S2: Place the semiconductor power chip (1) on the prefabricated layer of the first connection layer (2) and perform the first drying process; S3: Print sintered silver paste on the second electrode (102) of the chip (1) to form a prefabricated layer of the second connection layer (6), and perform a second drying process; S4: Position the first metal structural component (5), the second metal structural component (7), and the third metal structural component (9) in predetermined positions using tooling; S5: Perform a pressure sintering process to simultaneously densify the first connecting layer (2), the second connecting layer (6), and the third connecting layer (8) to form a strong electrical connection; S6: The third electrode (103) of the chip (1) is connected to the first metal structure (5) by wire bonding process using wire (4). S7: Inject insulating sealing material and cure it to form an insulating sealing structure (10) covering the chip (1) and the internal connection structure. S8: Place the package obtained in step S7 into the sealed liquid cooling device (11) and fill it with insulating coolant.

9. The preparation method according to claim 8, characterized in that, The pressure sintering process parameters in step S5 are: upper mold temperature 240°C ~ 260°C, lower mold temperature 250°C ~ 270°C, pressure 20MPa ~ 30MPa, and holding time 250 seconds ~ 350 seconds; the curing conditions in step S7 are: temperature 140°C ~ 160°C, and time 1.5 hours ~ 2.5 hours.

10. A power semiconductor half-bridge or full-bridge inverter module, characterized in that, include: Multiple power module units with direct liquid-cooled insulating packaging without ceramic substrate as described in any one of claims 1-7; Among them, the metal blocks (3) of each power module unit are insulated from each other by the insulating sealing structure (10) and the insulating coolant in the sealing liquid cooling device (11), and together they form a half-bridge or full-bridge inverter circuit, forming a DC positive pole DC+, DC negative pole DC- and AC output potential regions that are insulated from each other.

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