A single-tube self-positioning 3D packaging power module and a preparation process thereof

Abstract

The present application relates to a kind of single tube self-positioning 3D packaging power module and its preparation process, belong to power semiconductor device packaging technical field.3D packaging power module module includes intermediate substrate, upper substrate, lower substrate, three-phase full-bridge single tube assembly and power terminal;Intermediate substrate upper and lower surfaces are provided with single tube limiting groove, and upper bridge arm single tube and lower bridge arm single tube are respectively arranged in the recess on the upper and lower sides of intermediate substrate;Upper substrate and lower substrate are respectively attached with upper bridge arm single tube and lower bridge arm single tube to realize electrical connection-.Preparation process includes intermediate substrate preparation, single tube attachment, first sintering, upper and lower substrate attachment, secondary sintering and double-sided heat dissipation component installation and the like steps.The present application realizes single tube self-positioning by single tube limiting groove, realizes reliable connection by two-step sintering process-It has the advantages of high positioning accuracy, good heat dissipation performance, low parasitic inductance, process consistency is strong.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor packaging technology, and in particular to a single-tube self-positioning 3D packaged power module and its fabrication process. Background Technology

[0002] Three-phase full-bridge circuits are the core power topology in fields such as new energy inverters, industrial frequency conversion, power conversion, and rail transportation. With the popularization of wide-bandgap semiconductor devices such as silicon carbide and gallium nitride chips, power modules are gradually developing towards higher frequency, higher power density, and miniaturization.

[0003] Traditional three-phase full-bridge power modules mostly adopt a planar 2D packaging structure, with all power chips arranged in a single layer. The DC bus positive and negative terminals are scattered, resulting in a large loop area. In addition, the conventional planar package has an asymmetrical layout of each phase bridge arm, poor current path consistency, and is prone to problems such as local overheating and uneven device aging during long-term operation. Furthermore, the substrate integration is low, the electrical interconnection structure is cumbersome, and the overall integration and structural stability are insufficient.

[0004] To address the shortcomings of the existing technology, there is an urgent need to design a single-tube self-positioning 3D packaged power module and its fabrication process. Summary of the Invention

[0005] The first objective of this invention is to provide a 3D packaged power module with single-tube self-positioning, which solves the problems of low single-tube positioning accuracy and low mass production efficiency in traditional modules.

[0006] A single-tube self-positioning 3D packaged power module includes an intermediate substrate, an upper substrate, a lower substrate, a three-phase full-bridge single-tube assembly, and power terminals.

[0007] The intermediate substrate has several conductive pillars inside, which realize the electrical connection between the upper and lower circuit layers of the intermediate substrate; the upper and lower surfaces of the intermediate substrate are both provided with single-tube limiting grooves.

[0008] The three-phase full-bridge single-tube assembly includes several three-phase upper bridge arm single tubes and several three-phase lower bridge arm single tubes; the upper surface of the intermediate substrate is arranged with the three-phase upper bridge arm single tubes according to the three-phase full-bridge topology, and the lower surface of the intermediate substrate is arranged with the three-phase lower bridge arm single tubes according to the three-phase full-bridge topology, and both the three-phase upper bridge arm single tubes and the three-phase lower bridge arm single tubes are set in their corresponding single tube limiting grooves;

[0009] The upper substrate is disposed above the middle substrate and is attached to all three-phase upper bridge arm single tubes to achieve electrical connection.

[0010] The lower substrate is disposed below the middle substrate and is mounted on all three-phase lower bridge arm single tubes to achieve electrical connection.

[0011] The power terminals include DC bus terminals and AC input terminals, which are disposed on the side of the intermediate substrate and electrically connected to the upper and lower circuit layers of the intermediate substrate through conductive pillars.

[0012] Specifically, the lower surface of the upper substrate and the upper surface of the lower substrate are provided with positioning grooves. The positioning grooves on the lower surface of the upper substrate correspond one-to-one with the single tube limiting grooves on the upper surface of the intermediate substrate and are located directly above the corresponding single tube limiting grooves. The positioning grooves on the upper surface of the lower substrate correspond one-to-one with the single tube limiting grooves on the lower surface of the intermediate substrate and are located directly below the corresponding single tube limiting grooves.

[0013] Specifically, the intermediate substrate is a PCB substrate, and the upper substrate and the lower substrate are both AMB ceramic substrates;

[0014] The lower surface of the upper substrate, the upper surface of the lower substrate, and the upper and lower surfaces of the middle substrate are all provided with partitioned patterned wiring adapted to the three-phase bridge arms.

[0015] Specifically, the single tubes of the three-phase upper bridge arm and the single tubes of the three-phase lower bridge arm are arranged in a staggered array, and the circuit structures of each phase are symmetrically set.

[0016] Specifically, the DC bus terminals and AC input terminals are respectively arranged on both sides of the module to achieve a zoned wiring layout.

[0017] Furthermore, the positive and negative terminals of the DC bus terminals are distributed at the same end of the intermediate substrate and are stacked.

[0018] Preferably, it also includes a double-sided heat dissipation assembly, the double-sided water cooling assembly including an upper water cooling cover plate and a lower water cooling cover plate, the upper water cooling cover plate being attached to the outer side of the upper substrate, the lower water cooling cover plate being attached to the outer side of the lower substrate, and the upper water cooling cover plate and the lower water cooling cover plate respectively having independent cooling channels inside.

[0019] Specifically, the conductive pillar is made of molybdenum-copper alloy.

[0020] Specifically, the number of the three-phase upper arm single tube and the number of three-phase lower arm single tubes are both 30.

[0021] Specifically, the three-phase upper arm single tube and the three-phase lower arm single tube are made of at least one of silicon carbide power chips, IGBT power chips, gallium nitride power chips, MOSFET power chips, diode power chips, diamond power chips or gallium oxide power chips.

[0022] Specifically, the upper and lower circuit layers of the intermediate substrate are uniformly provided with a plurality of sets of protrusions, the protrusions including a first protrusion and a second protrusion; in each set of protrusions, the single tube limiting groove is formed in the region between the first protrusion and the second protrusion.

[0023] The first protrusion and the bottom of the single tube are connected by sintered silver or solder paste;

[0024] The second protrusion matches the shape of the outer edge of the single tube; the surface of the second protrusion is higher than the height of the single tube;

[0025] The first protrusion is lower than the surface of the second protrusion.

[0026] The second objective of this invention is to provide a fabrication process for a single-tube self-positioning 3D packaged power module, used to fabricate the aforementioned single-tube self-positioning 3D packaged power module, comprising the following steps:

[0027] Step S1: Preparation of intermediate substrate;

[0028] An intermediate substrate is provided, on which upper and lower circuit layers are fabricated respectively, and wiring patterns are designed according to a three-phase full-bridge topology partition. Several through holes are opened at predetermined positions on the intermediate substrate, and molybdenum-copper alloy conductive pillars are filled in the through holes to achieve electrical connection between the upper and lower circuit layers through the conductive pillars. Single tube limiting grooves are fabricated on the upper and lower surfaces of the intermediate substrate respectively, and the positions of the single tube limiting grooves correspond one-to-one with the layout positions of the single tubes in the three-phase full-bridge topology partition. At the same time, protrusions are fabricated on the upper and lower circuit layers of the intermediate substrate. Each set of protrusions includes a first protrusion and a second protrusion, and the area between the first protrusion and the second protrusion forms a single tube limiting groove.

[0029] Step S2: Fabrication of the upper and lower substrates;

[0030] An upper substrate and a lower substrate are provided, both of which are AMB ceramic substrates. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the lower surface of the upper substrate, and a positioning groove is formed on the lower surface of the upper substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the upper surface of the intermediate substrate. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the upper surface of the lower substrate, and a positioning groove is formed on the upper surface of the lower substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the lower surface of the intermediate substrate.

[0031] Step S3: Power terminal preparation and installation;

[0032] DC bus terminals and AC input terminals are fabricated and placed on the side of the intermediate substrate. They are electrically connected to the upper and lower circuit layers of the intermediate substrate through conductive posts. The positive and negative terminals of the DC bus terminals are distributed on the same end of the intermediate substrate and stacked, while the AC input terminals are arranged on the other end of the intermediate substrate.

[0033] Step S4: Single tube mounting of the three-phase upper arm;

[0034] A connecting material, such as sintered silver solder paste or tin paste, is coated in the single-tube positioning grooves on the upper surface of the intermediate substrate. The three-phase upper bridge arm single tubes are placed one-to-one into the single-tube positioning grooves on the upper surface of the intermediate substrate using a surface mount device, thus achieving physical positioning of the single tubes. The bottom of each single tube is electrically connected to the upper circuit layer of the intermediate substrate via a first protrusion. The surface of the second protrusion is higher than the height of the single tube, and the surface of the first protrusion is lower than the surface of the second protrusion.

[0035] Step S5: Single tube mounting of the three-phase lower arm;

[0036] A connecting material is coated in the single tube limiting groove on the lower surface of the intermediate substrate. The intermediate substrate is flipped over, and the single tubes of the three-phase lower bridge arm are placed one by one in the single tube limiting groove on the lower surface of the intermediate substrate using a chip mounting device. The single tube is physically positioned by using the single tube limiting groove. The bottom of the single tube is electrically connected to the lower circuit layer of the intermediate substrate through the first protrusion.

[0037] Step S6: One-time sintering and curing;

[0038] The intermediate substrate with single tube mounting completed is sent into a sintering furnace for a first heating sintering, so that the single tubes of the three-phase upper bridge arm and the single tubes of the three-phase lower bridge arm can form reliable electrical and mechanical connections with the upper and lower circuit layers of the intermediate substrate, respectively.

[0039] Step S7: Mounting the substrate;

[0040] Apply connecting material to the positioning grooves on the lower surface of the upper substrate and to the corresponding positions of the partitioned patterned wiring; place the upper substrate above the middle substrate, aligning the positioning grooves on the lower surface of the upper substrate with the single tube limiting grooves on the upper surface of the middle substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the upper substrate and the middle substrate; attach the lower surface of the upper substrate to the top of all three-phase upper bridge arm single tubes to achieve electrical connection.

[0041] Step S8: Lower substrate mounting; Apply connecting material to each positioning groove on the upper surface of the lower substrate and the corresponding positions of the partitioned patterned wiring; Place the lower substrate below the intermediate substrate, aligning the positioning grooves on the upper surface of the lower substrate with the single tube limiting grooves on the lower surface of the intermediate substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the lower substrate and the intermediate substrate; Mount the upper surface of the lower substrate to the top of all three-phase lower bridge arm single tubes to achieve electrical connection.

[0042] Step S9: Secondary sintering and curing; The laminated structure with the upper and lower substrates mounted is sent into a sintering furnace for secondary heating and sintering, so that reliable electrical and mechanical connections are formed between the upper substrate and the single tube of the three-phase upper bridge arm, and between the lower substrate and the single tube of the three-phase lower bridge arm.

[0043] Step S10: Install the double-sided heat dissipation assembly;

[0044] An upper water-cooling cover plate and a lower water-cooling cover plate are provided, and the upper water-cooling cover plate and the lower water-cooling cover plate are respectively provided with independent cooling channels inside; the upper water-cooling cover plate is attached to the outside of the upper substrate, and the lower water-cooling cover plate is attached to the outside of the lower substrate, and heat conduction connection is achieved through thermally conductive connecting material.

[0045] Step S11: Encapsulation and protection;

[0046] The stacked structure that has completed the above steps is then encapsulated and protected to form the final 3D packaged power module.

[0047] Specifically, the method for fabricating the single-tube limiting groove in step S1 is as follows: During the fabrication of the circuit layer of the intermediate substrate, several sets of protrusions are formed on the upper and lower surfaces of the intermediate substrate through patterned etching or mechanical processing. The area between the first protrusion and the second protrusion in each set constitutes a single-tube limiting groove; the first protrusion is used to connect with the bottom of the single tube, and the second protrusion is used to limit the single tube.

[0048] The single-tube self-positioning 3D packaged power module and its fabrication process of the present invention have the following advantages compared with the prior art:

[0049] (1) 3D stereoscopic integrated architecture: The three-layer stereoscopic packaging of the middle substrate + upper substrate + lower substrate is adopted. The upper and lower bridge arms are arranged in single tubes in the upper and lower layers. The single tube limiting groove is used to achieve precise limiting installation. The structure is compact, the space utilization rate is high, and the overall volume of the module is effectively reduced, and the power density is improved. The vertical conductive pillars realize the rapid conduction of the upper and lower circuit layers, simplifying the internal wiring structure.

[0050] (2) Stacked busbars + symmetrical layout, significantly reducing stray inductance: The positive and negative terminals of the DC busbars are stacked at the same end, and the positive and negative currents are transmitted in opposite parallel directions, and the magnetic fields cancel each other out; the three-phase bridge arms are arranged in a staggered array symmetrically, and the current path length of each phase is consistent, and the power loop area is significantly reduced, which effectively reduces the stray inductance of the busbars, suppresses high-frequency switching spikes and electromagnetic interference, and is suitable for high-frequency operating scenarios of wide bandgap devices;

[0051] (3) Excellent structure and electrical performance: The intermediate substrate adopts PCB substrate, which is flexible in wiring and highly integrated; the conductive pillars are made of molybdenum copper alloy, which has excellent conductivity and good thermal expansion coefficient matching, reducing thermal cycling stress; each phase bridge arm is completely symmetrically arranged, and the three-phase current balance is good, avoiding local overload aging.

[0052] (4) High-efficiency double-sided heat dissipation: The upper and lower independent water-cooled covers are set up to simultaneously dissipate heat from the upper bridge arm and the lower bridge arm single tubes, breaking the bottleneck of traditional single-sided heat dissipation; with the AMB ceramic substrate, the thermal conductivity is high and the insulation performance is excellent, which can quickly dissipate the working heat of the chip, reduce the chip junction temperature, and improve the continuous current carrying capacity and operating stability of the module.

[0053] (5) Strong universality and adaptability: It is compatible with a variety of mainstream power chips such as IGBT, MOSFET, silicon carbide, gallium nitride, and gallium oxide, and has a wide range of applications; the power terminals are arranged in zones, and the strong and weak currents and AC and DC are isolated. The wiring is neat and the whole machine has strong assembly compatibility.

[0054] (6) Precise positioning and self-alignment. The single tube is physically self-positioned by the single tube limiting groove and the second protrusion with a height difference, which reduces the dependence on the mounting accuracy and ensures parallel current sharing; prevents solder overflow, the second protrusion forms a dam structure to limit the overflow of molten solder, eliminate the risk of short circuit and improve the yield; chip mechanical protection, the second protrusion acts as a support pillar to buffer the mounting pressure during double-sided pressing, prevents chip breakage and ensures uniform thickness of the bonding layer. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of a single-tube self-positioning 3D packaged power module and its fabrication process, as shown in Example 1. Figure 1 ;

[0056] Figure 2 This is a schematic diagram of the structure of a single-tube self-positioning 3D packaged power module and its fabrication process, as shown in Example 1. Figure 2 ;

[0057] Figure 3 This is a schematic diagram of the structure of the intermediate substrate in Example 1;

[0058] Figure 4 This is a schematic diagram of the upper substrate structure in Example 1;

[0059] Figure 5 This is a schematic diagram of the structure of a single-tube self-positioning 3D packaged power module and its fabrication process, as shown in Example 1. Figure 3 ;

[0060] Figure 6 This is a schematic diagram of the structure of the protruding portion in Example 2. Detailed Implementation

[0061] The specific embodiments of this invention will be further described in detail below with reference to the accompanying drawings.

[0062] Example 1

[0063] like Figure 1 and Figure 2 As shown, a single-tube self-positioning 3D packaged power module and its fabrication process are disclosed, including an intermediate substrate 1, an upper substrate 2, a lower substrate 3, a three-phase full-bridge single-tube assembly, and power terminals.

[0064] The intermediate substrate 1 is a PCB substrate, such as Figure 3 As shown, its internal array is embedded with conductive pillars 4 made of molybdenum-copper alloy. The conductive pillars 4 are arranged to penetrate along the thickness direction of the intermediate substrate 1, stably conducting the upper and lower circuit layers of the intermediate substrate 1; as Figure 3 As shown, the upper and lower surfaces of the intermediate substrate 1 are integrally formed with an array of single-tube limiting grooves 5, which are used to achieve the initial limiting and fixing of the single tube.

[0065] like Figure 4 As shown, both the upper substrate 2 and the lower substrate 3 are made of AMB ceramic substrate, which has the characteristics of high thermal conductivity, high insulation, and high mechanical strength. Positioning grooves 6 are respectively formed on the lower surface of the upper substrate 2 and the upper surface of the lower substrate 3. The positioning grooves 6 correspond one-to-one with the single-tube limiting grooves 5 of the intermediate substrate 1, forming a positioning constraint structure that ensures the installation accuracy of the single tube. The bonding surfaces of the intermediate substrate 1, upper substrate 2, and lower substrate 3 are all prepared with partitioned patterned wiring 7, strictly matching the three-phase full-bridge topology to ensure the consistency of the electrical parameters of the three-phase circuit.

[0066] The three-phase full-bridge single-tube assembly includes several three-phase upper bridge arm single tubes 8 and several three-phase lower bridge arm single tubes 9; the upper surface of the intermediate substrate 1 is arranged with the three-phase upper bridge arm single tubes 8 according to the three-phase full-bridge topology, and the lower surface of the intermediate substrate 1 is arranged with the three-phase lower bridge arm single tubes 9 according to the three-phase full-bridge topology, and both the three-phase upper bridge arm single tubes 8 and the three-phase lower bridge arm single tubes 9 are set in the corresponding single tube limiting grooves 5.

[0067] The upper substrate 2 is disposed above the middle substrate 1 and is attached to all three-phase upper bridge arm single tubes 8 to achieve electrical connection.

[0068] The lower substrate 3 is disposed below the middle substrate 1 and is attached to all three-phase lower bridge arm single tubes 9 to achieve electrical connection.

[0069] The power terminals include DC bus terminals and AC input terminals 10. The DC bus terminals and AC input terminals 10 are disposed on the side of the intermediate substrate and are electrically connected to the upper and lower circuit layers of the intermediate substrate 1 through conductive pillars 4.

[0070] In this embodiment, the three-phase full-bridge single-transistor assembly includes thirty three-phase upper bridge arm single transistors 8 and thirty three-phase lower bridge arm single transistors 9. The three-phase upper bridge arm single transistors 8 are installed in sections within the single-transistor limiting grooves on the upper surface of the intermediate substrate 1, and the three-phase lower bridge arm single transistors 9 are correspondingly installed within the single-transistor limiting grooves on the lower surface of the intermediate substrate 1. All bridge arm single transistors are arranged in a staggered array, and the A, B, and C phases are completely symmetrical to ensure balanced three-phase current output. The power single transistors can be selected from any one or more chip combinations such as silicon carbide, IGBT, gallium nitride, MOSFET, diode, gallium oxide, and diamond, depending on the application requirements.

[0071] In this embodiment, the power output terminals are divided into DC bus terminals and AC input terminals. These two types of terminals are respectively installed on the left and right sides of the intermediate substrate 1 to achieve partitioned and isolated wiring. The positive terminal 11 and negative terminal 12 of the DC bus are concentrated at the same end of the intermediate substrate 1, stacked vertically with an insulating layer in between, forming a compact reverse current loop to minimize stray inductance. Each power output terminal establishes a stable electrical connection with the upper and lower circuit layers through conductive pillars inside the intermediate substrate.

[0072] like Figure 5 As shown, the outer side of the packaging structure is equipped with a double-sided heat dissipation assembly, including an upper water-cooling cover plate 13 and a lower water-cooling cover plate 14. The upper water-cooling cover plate 13 is tightly fitted to the outer side of the upper substrate 2, and the lower water-cooling cover plate 14 is tightly fitted to the outer side of the lower substrate 3. The two sets of water-cooling covers are independent of each other, and each has a continuous cooling channel inside, which can be circulated with cooling medium separately to achieve synchronous heat dissipation of the upper and lower bridge arm devices, and the heat dissipation efficiency is greatly improved.

[0073] All electrical connections within the module are achieved using low-temperature welding and sintering processes. Combined with three-dimensional interconnection of vertical conductive pillars, the overall circuit impedance is low and the current carrying capacity is strong. The overall 3D three-dimensional packaging structure is compact and highly modular, and can be directly applied in batches to three-phase power conversion equipment such as photovoltaic inverters, energy storage converters, industrial frequency converters, and new energy vehicle electronic control systems.

[0074] Example 2

[0075] In this embodiment, as Figure 6As shown, the upper and lower circuit layers of the intermediate substrate 1 are uniformly provided with a plurality of sets of protrusions, the protrusions including a first protrusion 15 and a second protrusion 16; in each set of protrusions, the single tube limiting groove 5 is formed in the region between the first protrusion 15 and the second protrusion 16; the first protrusion 15 and the bottom of the single tube are connected by sintered silver or solder paste; the shape of the second protrusion 16 matches the outer edge of the single tube; the surface of the second protrusion 16 is higher than the height of the single tube; the first protrusion 15 is lower than the surface of the second protrusion.

[0076] The remaining features are the same as in Example 1.

[0077] The inner edge contour of the second protrusion 16 matches the outer edge shape of the single tube. During the placement process, when the placement equipment places the single tube into the positioning groove, even with a certain pick-and-place position deviation, the outer edge of the single tube will automatically slide and adjust along the inner wall edge of the second protrusion 16 under the combined action of gravity and the surface tension of the molten solder, until the single tube is precisely "nested" in the center of the groove. This passive self-positioning mechanism allows the module to ensure the positional consistency of each parallel single tube without relying on high-precision placement equipment, thereby ensuring the flow sharing characteristics when multiple single tubes are connected in parallel.

[0078] During sintering or reflow soldering, the sintered silver or solder paste between the first protrusion 15 and the bottom of the single tube melts upon heating, becoming liquid or semi-liquid. At this time, because the top surface of the second protrusion 16 is higher than the top surface of the single tube, and the second protrusion forms a closed-loop structure around the outer edge of the single tube, the second protrusion constitutes a physical "dam" around the single tube. The molten solder is effectively confined to the area between the first protrusion and the bottom surface of the single tube, preventing it from overflowing to adjacent circuit layers or adjacent single tube areas, completely eliminating the risk of short circuits caused by solder bridging, while ensuring the uniformity of the connection layer thickness.

[0079] Example 3

[0080] A fabrication process for a single-tube self-positioning 3D packaged power module includes the following steps:

[0081] Step S1: Preparation of intermediate substrate;

[0082] An intermediate substrate is provided, on which upper and lower circuit layers are fabricated respectively, and wiring patterns are designed according to a three-phase full-bridge topology. Several through-holes are opened at predetermined positions on the intermediate substrate, and molybdenum-copper alloy conductive pillars are filled within the through-holes to achieve electrical connection between the upper and lower circuit layers through the conductive pillars. Single-tube limiting grooves are fabricated on the upper and lower surfaces of the intermediate substrate, the positions of which correspond one-to-one with the placement positions of single tubes in the three-phase full-bridge topology. Simultaneously, protrusions are fabricated on the upper and lower circuit layers of the intermediate substrate, each group of protrusions including a first protrusion and a second protrusion, the area between which forms a single-tube limiting groove. In step S1, a non-uniform height double-protrusion structure—a first protrusion (low) and a second protrusion (high)—is fabricated on the circuit layers of the intermediate substrate by patterned etching or mechanical processing, the area between which constitutes a single-tube limiting groove. The contour of this groove precisely matches the outer edge shape of the single tube.

[0083] Step S2: Fabrication of the upper and lower substrates;

[0084] An upper substrate and a lower substrate are provided, both of which are AMB ceramic substrates. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the lower surface of the upper substrate, and a positioning groove is formed on the lower surface of the upper substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the upper surface of the intermediate substrate. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the upper surface of the lower substrate, and a positioning groove is formed on the upper surface of the lower substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the lower surface of the intermediate substrate.

[0085] Step S3: Power terminal preparation and installation;

[0086] DC bus terminals and AC input terminals are fabricated and placed on the side of the intermediate substrate. They are electrically connected to the upper and lower circuit layers of the intermediate substrate through conductive posts. The positive and negative terminals of the DC bus terminals are distributed on the same end of the intermediate substrate and stacked, while the AC input terminals are arranged on the other end of the intermediate substrate.

[0087] Step S4: Single tube mounting of the three-phase upper arm;

[0088] A connecting material, such as sintered silver solder paste or tin paste, is coated in the single-tube positioning grooves on the upper surface of the intermediate substrate. The three-phase upper bridge arm single tubes are placed one-to-one into the single-tube positioning grooves on the upper surface of the intermediate substrate using a surface mount device, thus achieving physical positioning of the single tubes. The bottom of each single tube is electrically connected to the upper circuit layer of the intermediate substrate via a first protrusion. The surface of the second protrusion is higher than the height of the single tube, and the surface of the first protrusion is lower than the surface of the second protrusion.

[0089] Step S5: Single tube mounting of the three-phase lower arm;

[0090] A connecting material is coated in the single tube limiting groove on the lower surface of the intermediate substrate. The intermediate substrate is flipped over, and the single tubes of the three-phase lower bridge arm are placed one by one in the single tube limiting groove on the lower surface of the intermediate substrate using a chip mounting device. The single tube is physically positioned by using the single tube limiting groove. The bottom of the single tube is electrically connected to the lower circuit layer of the intermediate substrate through the first protrusion.

[0091] During the placement process in steps S4 and S5, when the placement device places a single tube into the corresponding single tube positioning groove, even if there is a certain pick-and-place position deviation (e.g., ±50μm), the single tube will automatically slide along the inner edge of the second protrusion to the center of the groove under the combined action of gravity and the surface tension of the subsequent molten solder, due to the physical constraint formed by the inner wall of the second protrusion on the outer wall of the single tube. This achieves passive self-positioning. This mechanism ensures that the positional offset of multiple parallel single tubes is highly consistent, thereby guaranteeing the consistency of parasitic parameters of the parallel branches and laying a structural foundation for excellent current sharing characteristics.

[0092] In addition, in steps S4 and S5, a connecting material (sintered silver solder paste or tin paste) is applied to the surface of the first protrusion. Since the top surface of the second protrusion is higher than the top surface of the single tube and forms a closed-loop structure around the outer edge of the single tube, the second protrusion constitutes a physical "dam" around the single tube. During the first sintering process in step S6, the molten connecting material is effectively blocked by the inner wall of the second protrusion, preventing it from overflowing to adjacent circuit layers or adjacent single tube areas, ensuring that the solder is precisely confined within the connection area between the first protrusion and the bottom surface of the single tube. This eliminates the risk of short circuits caused by solder bridging and ensures the uniformity of the thickness of the connection layers for each single tube.

[0093] Step S6: One-time sintering and curing;

[0094] The intermediate substrate with single tube mounting completed is sent into a sintering furnace for a first heating sintering, so that the single tubes of the three-phase upper bridge arm and the single tubes of the three-phase lower bridge arm can form reliable electrical and mechanical connections with the upper and lower circuit layers of the intermediate substrate, respectively.

[0095] Step S7: Mounting the substrate;

[0096] Apply connecting material to the positioning grooves on the lower surface of the upper substrate and to the corresponding positions of the partitioned patterned wiring; place the upper substrate above the middle substrate, aligning the positioning grooves on the lower surface of the upper substrate with the single tube limiting grooves on the upper surface of the middle substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the upper substrate and the middle substrate; attach the lower surface of the upper substrate to the top of all three-phase upper bridge arm single tubes to achieve electrical connection.

[0097] Step S8: Lower substrate mounting; Apply connecting material to each positioning groove on the upper surface of the lower substrate and the corresponding positions of the partitioned patterned wiring; Place the lower substrate below the intermediate substrate, aligning the positioning grooves on the upper surface of the lower substrate with the single tube limiting grooves on the lower surface of the intermediate substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the lower substrate and the intermediate substrate; Mount the upper surface of the lower substrate to the top of all three-phase lower bridge arm single tubes to achieve electrical connection.

[0098] In steps S7 and S8, the upper and lower substrates form a one-to-one nested fit with the single-tube limiting groove on the middle substrate through the positioning grooves on them. This fit is a mechanical hard positioning, and the positioning accuracy is directly determined by the machining accuracy of the grooves (up to ±10μm level), without relying on the accuracy of external visual alignment equipment. During assembly, the upper / lower substrate is simply roughly placed on the middle substrate, and under the action of pressing force, the correspondence between the positioning grooves and the single-tube limiting grooves can automatically guide the three to the designed position. At the same time, since the top of each single tube is limited by the second protrusion in its Z-direction height relative to the middle substrate, the height direction of each contact point of the upper / lower substrate is consistent when it is placed, avoiding localized poor connection or overpressure caused by single tube height deviation.

[0099] Step S9: Secondary sintering and curing; The laminated structure with the upper and lower substrates mounted is sent into a sintering furnace for secondary heating and sintering, so that reliable electrical and mechanical connections are formed between the upper substrate and the single tube of the three-phase upper bridge arm, and between the lower substrate and the single tube of the three-phase lower bridge arm.

[0100] Step S10: Install the double-sided heat dissipation assembly;

[0101] An upper water-cooling cover plate and a lower water-cooling cover plate are provided, and the upper water-cooling cover plate and the lower water-cooling cover plate are respectively provided with independent cooling channels inside; the upper water-cooling cover plate is attached to the outside of the upper substrate, and the lower water-cooling cover plate is attached to the outside of the lower substrate, and heat conduction connection is achieved through thermally conductive connecting material.

[0102] Step S11: Encapsulation and protection;

[0103] The stacked structure that has completed the above steps is then encapsulated and protected to form the final 3D packaged power module.

[0104] In this embodiment, the method for manufacturing the single tube limiting groove in step S1 is as follows: during the fabrication of the circuit layer of the intermediate substrate, several sets of protrusions are formed on the upper and lower surfaces of the intermediate substrate by patterned etching or mechanical processing. The area between the first protrusion and the second protrusion in each set of protrusions constitutes a single tube limiting groove. The first protrusion is used to connect with the bottom of the single tube, and the second protrusion is used to limit the single tube.

[0105] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A single-tube self-positioning 3D packaged power module, characterized in that, It includes an intermediate substrate, an upper substrate, a lower substrate, a three-phase full-bridge single-transistor assembly, and power terminals; The intermediate substrate has several conductive pillars inside, which realize the electrical connection between the upper and lower circuit layers of the intermediate substrate; the upper and lower surfaces of the intermediate substrate are both provided with single-tube limiting grooves. The three-phase full-bridge single-tube assembly includes several three-phase upper bridge arm single tubes and several three-phase lower bridge arm single tubes; the upper surface of the intermediate substrate is arranged with the three-phase upper bridge arm single tubes according to the three-phase full-bridge topology, and the lower surface of the intermediate substrate is arranged with the three-phase lower bridge arm single tubes according to the three-phase full-bridge topology, and both the three-phase upper bridge arm single tubes and the three-phase lower bridge arm single tubes are set in their corresponding single tube limiting grooves; The upper substrate is disposed above the middle substrate and is attached to all three-phase upper bridge arm single tubes to achieve electrical connection. The lower substrate is disposed below the middle substrate and is mounted on all three-phase lower bridge arm single tubes to achieve electrical connection. The power terminals include DC bus terminals and AC input terminals, which are disposed on the side of the intermediate substrate and electrically connected to the upper and lower circuit layers of the intermediate substrate through conductive pillars.

2. The single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The lower surface of the upper substrate and the upper surface of the lower substrate are both provided with positioning grooves. The positioning grooves on the lower surface of the upper substrate correspond one-to-one with the single tube limiting grooves on the upper surface of the intermediate substrate and are located directly above the corresponding single tube limiting grooves. The positioning grooves on the upper surface of the lower substrate correspond one-to-one with the single tube limiting grooves on the lower surface of the intermediate substrate and are located directly below the corresponding single tube limiting grooves.

3. The single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The intermediate substrate is a PCB substrate, and the upper and lower substrates are both AMB ceramic substrates. The lower surface of the upper substrate, the upper surface of the lower substrate, and the upper and lower surfaces of the middle substrate are all provided with partitioned patterned wiring adapted to the three-phase bridge arms.

4. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, Both the single tubes of the three-phase upper bridge arm and the single tubes of the three-phase lower bridge arm are arranged in a staggered array, with each phase circuit structure set symmetrically.

5. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The DC bus terminals and AC input terminals are respectively arranged on both sides of the module to achieve a zoned wiring layout.

6. A single-tube self-positioning 3D packaged power module according to claim 5, characterized in that, The positive and negative terminals of the DC bus terminals are located at the same end of the intermediate substrate and are stacked together.

7. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, It also includes a double-sided heat dissipation assembly, which includes an upper water-cooling cover plate and a lower water-cooling cover plate. The upper water-cooling cover plate is attached to the outside of the upper substrate, and the lower water-cooling cover plate is attached to the outside of the lower substrate. The upper water-cooling cover plate and the lower water-cooling cover plate are respectively provided with independent cooling channels inside.

8. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The conductive pillar is made of molybdenum-copper alloy.

9. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The number of each of the three-phase upper arm single tubes and the number of three-phase lower arm single tubes is 30.

10. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The three-phase upper arm single tube and the three-phase lower arm single tube adopt at least one of silicon carbide power chip, IGBT power chip, gallium nitride power chip, MOSFET power chip, diode power chip, diamond power chip or gallium oxide power chip.

11. A single-tube self-positioning 3D packaged power module according to claim 1, characterized in that, The upper and lower circuit layers of the intermediate substrate are uniformly provided with several sets of protrusions, including a first protrusion and a second protrusion; in each set of protrusions, the single tube limiting groove is formed in the area between the first protrusion and the second protrusion. The first protrusion and the bottom of the single tube are connected by sintered silver or solder paste; The second protrusion matches the shape of the outer edge of the single tube; the surface of the second protrusion is higher than the height of the single tube; The first protrusion is lower than the surface of the second protrusion.

12. A fabrication process for a single-tube self-positioning 3D packaged power module, used to fabricate the single-tube self-positioning 3D packaged power module as described in any one of claims 1 to 11, characterized in that, Includes the following steps, Step S1: Preparation of intermediate substrate; An intermediate substrate is provided, on which upper and lower circuit layers are fabricated respectively, and wiring patterns are designed according to a three-phase full-bridge topology partition. Several through holes are opened at predetermined positions on the intermediate substrate, and molybdenum-copper alloy conductive pillars are filled in the through holes to achieve electrical connection between the upper and lower circuit layers through the conductive pillars. Single tube limiting grooves are fabricated on the upper and lower surfaces of the intermediate substrate respectively, and the positions of the single tube limiting grooves correspond one-to-one with the layout positions of the single tubes in the three-phase full-bridge topology partition. At the same time, protrusions are fabricated on the upper and lower circuit layers of the intermediate substrate. Each set of protrusions includes a first protrusion and a second protrusion, and the area between the first protrusion and the second protrusion forms a single tube limiting groove. Step S2: Fabrication of the upper and lower substrates; An upper substrate and a lower substrate are provided, both of which are AMB ceramic substrates. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the lower surface of the upper substrate, and a positioning groove is formed on the lower surface of the upper substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the upper surface of the intermediate substrate. A partitioned patterned wiring adapted to the three-phase bridge arms is formed on the upper surface of the lower substrate, and a positioning groove is formed on the upper surface of the lower substrate, the positioning groove corresponding one-to-one with the single-tube limiting groove on the lower surface of the intermediate substrate. Step S3: Power terminal preparation and installation; DC bus terminals and AC input terminals are fabricated and placed on the side of the intermediate substrate. They are electrically connected to the upper and lower circuit layers of the intermediate substrate through conductive posts. The positive and negative terminals of the DC bus terminals are distributed on the same end of the intermediate substrate and stacked, while the AC input terminals are arranged on the other end of the intermediate substrate. Step S4: Single tube mounting of the three-phase upper arm; A connecting material, such as sintered silver solder paste or tin paste, is coated in the single-tube positioning grooves on the upper surface of the intermediate substrate. The three-phase upper bridge arm single tubes are placed one-to-one into the single-tube positioning grooves on the upper surface of the intermediate substrate using a surface mount device, thus achieving physical positioning of the single tubes. The bottom of each single tube is electrically connected to the upper circuit layer of the intermediate substrate via a first protrusion. The surface of the second protrusion is higher than the height of the single tube, and the surface of the first protrusion is lower than the surface of the second protrusion. Step S5: Single tube mounting of the three-phase lower arm; A connecting material is coated in the single tube limiting groove on the lower surface of the intermediate substrate. The intermediate substrate is flipped over, and the single tubes of the three-phase lower bridge arm are placed one by one in the single tube limiting groove on the lower surface of the intermediate substrate using a chip mounting device. The single tube is physically positioned by using the single tube limiting groove. The bottom of the single tube is electrically connected to the lower circuit layer of the intermediate substrate through the first protrusion. Step S6: One-time sintering and curing; The intermediate substrate with single tube mounting completed is sent into a sintering furnace for a first heating sintering, so that the single tubes of the three-phase upper bridge arm and the single tubes of the three-phase lower bridge arm can form reliable electrical and mechanical connections with the upper and lower circuit layers of the intermediate substrate, respectively. Step S7: Mounting the substrate; Apply connecting material to the positioning grooves on the lower surface of the upper substrate and to the corresponding positions of the partitioned patterned wiring; place the upper substrate above the middle substrate, aligning the positioning grooves on the lower surface of the upper substrate with the single tube limiting grooves on the upper surface of the middle substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the upper substrate and the middle substrate; attach the lower surface of the upper substrate to the top of all three-phase upper bridge arm single tubes to achieve electrical connection. Step S8: Lower substrate mounting; Apply connecting material to each positioning groove on the upper surface of the lower substrate and the corresponding positions of the partitioned patterned wiring; Place the lower substrate below the intermediate substrate, aligning the positioning grooves on the upper surface of the lower substrate with the single tube limiting grooves on the lower surface of the intermediate substrate, and use the cooperation of the positioning grooves and the single tube limiting grooves to achieve precise positioning of the lower substrate and the intermediate substrate; Mount the upper surface of the lower substrate to the top of all three-phase lower bridge arm single tubes to achieve electrical connection. Step S9: Secondary sintering and curing; The laminated structure with the upper and lower substrates mounted is sent into a sintering furnace for secondary heating and sintering, so that reliable electrical and mechanical connections are formed between the upper substrate and the single tube of the three-phase upper bridge arm, and between the lower substrate and the single tube of the three-phase lower bridge arm. Step S10: Install the double-sided heat dissipation assembly; An upper water-cooling cover plate and a lower water-cooling cover plate are provided, and the upper water-cooling cover plate and the lower water-cooling cover plate are respectively provided with independent cooling channels inside; the upper water-cooling cover plate is attached to the outside of the upper substrate, and the lower water-cooling cover plate is attached to the outside of the lower substrate, and heat conduction connection is achieved through thermally conductive connecting material. Step S11: Encapsulation and protection; The stacked structure that has completed the above steps is then encapsulated and protected to form the final 3D packaged power module.

13. The fabrication process of a single-tube self-positioning 3D packaged power module according to claim 12, characterized in that, The method for fabricating the single tube limiting groove in step S1 is as follows: During the fabrication of the circuit layer of the intermediate substrate, several sets of protrusions are formed on the upper and lower surfaces of the intermediate substrate by pattern etching or mechanical processing. The area between the first protrusion and the second protrusion in each set of protrusions constitutes the single tube limiting groove. The first protrusion is used to connect with the bottom of the single tube, and the second protrusion is used to limit the single tube.

Images