An IGBT packaging structure

Abstract

The application relates to an IGBT packaging structure, which comprises an insulating plate in a flat plate structure, a plurality of copper-coated areas are arranged on one side of the insulating plate, each copper-coated area is electrically connected through a conductive piece, a first copper-coated area provided with a first power pin is electrically connected with a second copper-coated area provided with a second power pin through a first conductive piece, and the second copper-coated area is electrically connected with a third copper-coated area provided with a third power pin through a second conductive piece, wherein the first conductive piece and the second conductive piece can be arranged as copper bars. The copper bars are arranged in parallel in space, the loop area is small, the magnetic fields formed can be offset to each other, the stray inductance of the current loop is extremely small, the switching peak stress of the device is small, and the high-frequency device is beneficial to work.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and more particularly to an IGBT packaging structure. Background Technology

[0002] IGBT, or Insulated Gate Bipolar Transistor, is a composite, fully controllable, voltage-driven power semiconductor device composed of a bipolar junction transistor (BJT) and a metal-oxide-semiconductor field-effect transistor (MOS). It combines the advantages of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) with the low on-state voltage drop of a giant transistor (GTR). GTRs have low saturation voltage and high current density, but require a large drive current; MOSFETs have very low drive power and fast switching speed, but a large on-state voltage drop and low current density. IGBTs combine the advantages of both devices, offering low drive power and low saturation voltage.

[0003] Generally, an IGBT has three terminals: collector, emitter, and gate, all of which are covered with metal layers. However, the metal material on the gate terminal has a silicon dioxide layer. The IGBT structure is essentially a four-layer semiconductor device. This four-layer device is achieved by combining PNP and NPN transistors, forming a PNPN arrangement. The IGBT operates by continuously activating and deactivating its gate terminal to turn it on and off. If a positive input voltage passes through the gate, the emitter remains on. Conversely, if the voltage at the IGBT's gate is zero or negative, the circuit is turned off.

[0004] IGBT modules are currently widely used in industrial control and power supply, new energy power generation, new energy vehicles and other fields. With the development of the industry, IGBT modules are required to have high switching frequency, high power density and high reliability.

[0005] CN209328880U discloses an IGBT packaging module, including a module body, the module body including a module shell, two auxiliary terminals exposed on the upper surface of one end of the module shell, three busbars provided inside the module shell, the busbar terminals of the three busbars exposed from the top of the module shell, and an outer cover on the module shell of each busbar, with the busbar terminals extending out of the outer cover.

[0006] CN107731768A discloses an IGBT module packaging structure, including an insulating substrate; at least two parallel branch groups of IGBT chips disposed on the insulating substrate; at least two emitter bus structures disposed on the insulating substrate in one-to-one correspondence with the parallel branch groups of IGBT chips, and the plurality of emitter bus structures are mutually insulated from each other, and the emitter of each parallel branch group of IGBT chips is electrically connected to its corresponding emitter bus structure; and an emitter end busbar disposed on the insulating substrate and electrically connected to each emitter bus structure.

[0007] CN111128981A discloses an IGBT module packaging structure and packaging method. The IGBT module packaging structure is characterized by comprising: a substrate capable of supporting an IGBT chip thereon; a housing covering the substrate and forming a cavity inside the housing to accommodate the IGBT chip, wherein the IGBT chip is disposed within the cavity; the cavity is further filled with a molding compound, and at least one downwardly extending partition is provided on the lower end surface of the top cover of the housing to separate the molding compound.

[0008] CN112421934A discloses an IGBT power module packaging structure and an IGBT power module using the packaging structure. The stacked busbar has a terminal in the middle, which is connected to the IGBT power device through a small copper busbar. This optimizes the connection between the IGBT power device and the stacked busbar, so that the current on the bus capacitor can reach the IGBT power device through the stacked busbar in a shorter path.

[0009] However, existing IGBT modules use aluminum wires to connect the internal chip surfaces, and the chips are connected on the same plane, resulting in a large current loop. This leads to a larger inductance in the loop, which causes voltage spikes when turned off, affecting the safe operating area of ​​the module. At the same time, the aluminum wire bonding method has a power cycle limit, affecting the reliability of the module.

[0010] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0011] To simplify processes and facilitate automated production, existing technologies typically arrange "devices" within a single plane. This results in a large area enclosed by the current loops on the IGBT module, leading to stray inductance. This makes conventional IGBT modules unsuitable for the high-frequency operation requirements of conventional devices. Stray inductance refers to the equivalent inductance exhibited by conductors in the circuit (such as connecting wires, component leads, and the component itself). Stray inductance causes high voltage spikes between the collector and emitter of the IGBT module, resulting in significant electromagnetic interference and even damage to the IGBT module. For example, in high-power converters, due to stray parameters in components and the DC bus, large voltage and current spikes are generated during the IGBT module's turn-on and turn-off processes. The voltage spike between the collector and emitter is particularly large at the moment of IGBT turn-off, increasing switching losses, generating strong electromagnetic interference, and even causing circuit resonance. Stray parameters in high-power converters include parasitic inductance from bus capacitance, stray inductance and resistance from the bus, inductance from switching device leads, and stray inductance from connecting bolts.

[0012] Therefore, in view of the shortcomings of the prior art, the present invention proposes an IGBT packaging structure to solve at least some of the above-mentioned technical problems.

[0013] The IGBT packaging structure disclosed in this invention includes an insulating plate with a flat structure. A plurality of copper-clad areas are provided on one side of the insulating plate. The copper-clad areas are electrically connected to each other through conductive elements. A first copper-clad area with a first power pin is electrically connected to a second copper-clad area with a second power pin through a first conductive element. The second copper-clad area is electrically connected to a third copper-clad area with a third power pin through a second conductive element. The first conductive element and the second conductive element can be configured as copper busbars.

[0014] Preferably, the inductance calculation formula shows that the stacked scheme of the present invention reduces stray inductance by at least 50%, preferably 60%, and even more preferably 70%. Preferably, by comparing the results of the inductance calculation formula, it is effectively verified that constructing stacked copper busbars with opposite but parallel current directions in space can cancel each other out, thereby reducing the stray inductance of the current loop, resulting in lower switching peak stress in the device and meeting the requirements for high-frequency device applications.

[0015] According to a preferred embodiment, a chip group consisting of a first power chip and a second power chip is disposed on the copper-clad area, wherein the first chip group is disposed in the first copper-clad area and the second chip group is disposed in the second copper-clad area.

[0016] According to a preferred embodiment, one side of the first conductive element is connected to the first chipset, and the other side is connected to the second copper-clad area; one side of the second conductive element is connected to the second chipset, and the other side is connected to the third copper-clad area, wherein the connection between the conductive element and the chipset can be connected to the corresponding first power chip and second power chip respectively.

[0017] Preferably, by applying the above technical solution, a first chipset is set in the first copper-plated area of ​​the insulating board, and a second chipset is set in the second copper-plated area. Both chipset and second chipset are soldered using solder pads or solder paste. The power chips of the first chipset and the first conductive component are connected by soldering, which improves the reliability of the device connection. Moreover, the first and second conductive components configured as copper busbars improve the current carrying capacity of the IGBT module compared to using copper or aluminum wires as conductive components. This increases the heat capacity of the first and second chipsets and improves their transient performance output capability, thus solving the problem of low power connection reliability in IGBT modules in the prior art.

[0018] According to a preferred embodiment, both the first conductive element and the second conductive element include a contact portion, a transition portion, and a main body portion. The contact portion is a part of the conductive element that contacts the corresponding copper-clad area or power chip. One side of the transition portion is connected to the contact portion, and the other side is connected to the main body portion.

[0019] According to a preferred embodiment, the main body portions of the first conductive element and the second conductive element can be arranged in a manner that is not coplanar with the corresponding copper-clad area and the power chip, so that when the main body portion is projected along the direction toward the insulating plate, it can sweep to form a three-dimensional space corresponding to different conductive elements.

[0020] According to a preferred embodiment, the first conductive element and the second conductive element can be arranged in a nested manner, such that the space formed by one conductive element can be substantially covered by the space formed by the other conductive element.

[0021] According to a preferred embodiment, the first conductive element nested within the second conductive element is not in contact with the second conductive element on the outside, and an electrical gap is provided between the main body portions of the first conductive element and the second conductive element based on the power supply voltage.

[0022] Preferably, to improve the elimination of stray inductance, the electrical gap can be set in a manner that is as small as possible without causing breakdown discharge. Preferably, the electrical gap can be set at least based on the magnitude of the supply voltage, and a relatively larger electrical gap is required as the supply voltage increases.

[0023] According to a preferred embodiment, the first conductive element and the second conductive element are arranged at least in a manner that increases the degree of overlap of the projected shapes of their main parts, wherein the degree of overlap of the projected shapes is the size of the intersection of the patterns of the main parts of the first conductive element and the second conductive element projected onto the insulating plate in the direction toward the insulating plate.

[0024] Preferably, the greater the overlap between the projected shapes of the first conductive element and the second conductive element, the more beneficial it is to cancel stray inductance.

[0025] According to a preferred embodiment, the first conductive element and / or the second conductive element can be disposed in a non-integral form to complete the welding work through through holes formed on the first conductive element and / or the second conductive element.

[0026] According to a preferred embodiment, an encapsulation shell with a height at least higher than the setting height of the second conductive element is disposed above the insulating plate.

[0027] Preferably, since the package shell usually has a certain height, and the stacked copper busbar of the present invention makes full use of this height, the devices that are distributed on the IGBT module can be set more centrally, so as to reduce the overall volume of the package structure and improve the power supply density of the IGBT module. Attached Figure Description

[0028] Figure 1 This is a structural diagram of an existing IGBT module provided by existing technology;

[0029] Figure 2 This is a schematic diagram of the structure of an IGBT module according to a preferred embodiment of the present invention.

[0030] List of reference numerals

[0031] 1: First copper-clad area; 2: First power chip; 3: First conductive component; 4: Second power chip; 5: Second conductive component; 6: Second power pin; 7: Third power pin; 8: First power pin; 9: Second copper-clad area; 10: Third copper-clad area; 11: Insulating plate; 12: Current loop; 13: Air inlet. Detailed Implementation

[0032] The following is a detailed explanation with reference to the accompanying drawings.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0036] The IGBT packaging structure provided by this invention can be an improvement and optimization of the existing IGBT packaging structure to form an IGBT module. The existing IGBT packaging structure can be as follows: Figure 1 As shown.

[0037] Furthermore, the existing IGBT packaging structure includes an insulating plate 11 and multiple copper-clad regions disposed on the insulating plate 11. The insulating plate 11 can be made of insulating materials such as ceramic. The copper-clad regions may include a first copper-clad region 1, a second copper-clad region 9, and a third copper-clad region 10. A first power pin 8, a second power pin 6, and a third power pin 7 are respectively connected to the first copper-clad region 1, the second copper-clad region 9, and the third copper-clad region 10 via ultrasonic welding or soldering. A first power chip 2 and a second power chip 4 can be connected via a first conductive element 3 to form a chip group, the connection method being ultrasonic welding, wherein the first conductive element 3 is an aluminum wire or a copper wire. The two chip groups can be respectively connected to the second copper-clad region 9 and the third copper-clad region 10 via their respective second conductive elements 5, the connection method being ultrasonic welding, wherein the second conductive element 5 is an aluminum wire or a copper wire. To simplify processes and facilitate automated production, existing technologies typically arrange various "devices" within a single plane. This results in a large area enclosed by the current loop 12 on the IGBT module, leading to stray inductance. Consequently, conventional IGBT modules cannot meet the operational requirements of high-frequency devices. Stray inductance refers to the equivalent inductance exhibited by conductors in the circuit (such as connecting wires, component leads, and component bodies). Stray inductance causes high voltage spikes between the collector and emitter of the IGBT module, resulting in significant electromagnetic interference and even damage to the IGBT module. For example, in high-power converters, due to stray parameters in components and the DC bus, large voltage and current spikes are generated during the IGBT module's turn-on and turn-off processes. In particular, the voltage spike between the collector and emitter is very large at the moment of IGBT module turn-off, increasing switching losses, generating strong electromagnetic interference, and even causing circuit resonance. The stray parameters in high-power converters include parasitic inductance of bus capacitance, stray inductance and resistance of the bus, inductance of switching device leads, and stray inductance of connecting bolts.

[0038] Based on this, the present invention provides, as follows Figure 2 The IGBT package structure shown may include an insulating plate 11 with a generally flat structure and multiple copper-clad regions disposed on the insulating plate 11. The insulating plate 11 may be made of insulating materials such as ceramic, and the copper-clad regions may include a first copper-clad region 1, a second copper-clad region 9, and a third copper-clad region 10. Preferably, the first copper-clad region 1, the second copper-clad region 9, and the third copper-clad region 10 may be arranged in an asymmetrical manner.

[0039] Preferably, a first power pin 8, a second power pin 6, and a third power pin 7 are respectively connected to the first copper-clad area 1, the second copper-clad area 9, and the third copper-clad area 10 by ultrasonic welding or soldering. More preferably, the first power pin 8 and the third power pin 7 are arranged close to each other, and the second power pin 6 is arranged far away from the first power pin 8 and the third power pin 7.

[0040] Preferably, the first power chip 2 and the second power chip 4 can form a chip group and be disposed on the corresponding copper-clad areas. The first chip group can be disposed on the first copper-clad area 1 and the second chip group can be disposed on the second copper-clad area 9. The chip group can be disposed by soldering with solder pads or solder paste.

[0041] Furthermore, the first chipset disposed on the first copper-clad area 1 is connected via a first conductive element 3, the other end of the first conductive element 3 is connected to the second copper-clad area 9, and the second chipset disposed on the second copper-clad area 9 is connected via a second conductive element 5, the other end of the second conductive element 5 is connected to the third copper-clad area 10, wherein both the first conductive element 3 and the second conductive element 5 are copper busbars. Preferably, the first power chip 2 and the second power chip 4 of the first chipset can be connected to the first conductive element 3 via a solder layer of a soldering process, and the first power chip 2 and the second power chip 4 of the second chipset can be connected to the second conductive element 5 via a solder layer of a soldering process.

[0042] By applying the above technical solution, a first chipset is set in the first copper-plated area 1 on the insulating board 11, and a second chipset is set in the second copper-plated area 9. Both can be set by soldering with solder pads or solder paste. The power chips of the first chipset are connected to the first conductive element 3, and the power chips of the second chipset are connected to the second conductive element 5 by soldering. This improves the reliability of the device connection. Moreover, the first conductive element 3 and the second conductive element 5, which are configured as copper busbars, improve the current carrying capacity of the IGBT module compared with copper wire or aluminum wire. This increases the heat capacity of the first chipset and the second chipset, and also improves the transient performance output capability of the first chipset and the second chipset. This solves the problem of low power connection reliability in the IGBT module in the prior art.

[0043] Preferably, the conductive element may include at least a contact portion, a transition portion, and a main body portion. The contact portion refers to the part of the conductive element that contacts the copper-clad area or power chip. One side of the transition portion is connected to the contact portion, and the other side is connected to the main body portion. Preferably, the conductive element may typically have multiple contact portions to be respectively connected to the corresponding copper-clad area and the first power chip 2 and the second power chip 4. The connection between the contact portion and the copper-clad area and the power chip is soldered, and it is typically soldered to its upper surface. This upper surface refers to the surface away from the insulating plate 11; that is, the contact portion can generally be considered to be coplanar with the upper surface of the contacting copper-clad area or power chip. Preferably, the main body can be arranged in a non-coplanar manner with both the copper-clad area and the power chip, so that the transition portions connecting the main body and the contact portion on both sides are arranged at a certain angle, thereby forming a space below the main body. This space below the main body refers to the three-dimensional space formed by the main body sweeping along the direction towards the insulating plate 11. The volume of this space is limited by the area and sweeping height of the main body, i.e., limited by the setting position of the contact portion and the setting method of the transition portion. The setting method of the transition portion includes the setting height and the setting angle. Preferably, the setting angle of the transition portion can be a right angle, and the main body can be arranged parallel to the upper surface of the copper-clad area. Preferably, the first conductive element 3 and the second conductive element 5 can form spaces of different volumes, so that the first conductive element 3 and the second conductive element 5 can be nested. This nesting means that the space formed by one conductive element can be roughly covered by the space formed by the other conductive element, forming spatial overlap. This saves packaging space and also helps to eliminate stray inductance. Furthermore, based on the placement of each copper-clad area and each power chip, the first conductive element 3 can preferably be nested within the second conductive element 5.

[0044] Preferably, the first conductive element 3 nested within the second conductive element 5 does not contact the second conductive element 5 on the outside, and a corresponding electrical gap is provided between their main body portions. To improve the elimination of stray inductance, the electrical gap is set in a manner that is as small as possible without causing breakdown discharge. Preferably, the electrical gap is set at least based on the magnitude of the supply voltage, and a relatively larger electrical gap is required as the supply voltage increases. For example, for a supply voltage of 650V, an electrical gap of approximately 1.5mm is required; for a supply voltage of 3300V, an electrical gap of approximately 3mm is required. Preferably, the line width of the current loop 12 formed spatially by the first conductive element 3 and the second conductive element 5 with the electrical gap is limited by the degree of overlap of the projected shapes between the first conductive element 3 and the second conductive element 5. This degree of overlap refers to the size of the intersection of the patterns projected onto the insulating plate 11 by the main body portions of the first conductive element 3 and the second conductive element 5 along the direction toward the insulating plate 11. Furthermore, the greater the overlap between the projected shapes of the first conductive element 3 and the second conductive element 5, the more beneficial it is to cancel out stray inductance.

[0045] Preferably, the contact portion of the first conductive element 3 can be connected to the first power chip 2, the second power chip 4, and the second copper-clad region 9 respectively disposed on the first copper-clad region 1, so as to achieve electrical connection through its transition portion and the main body portion. Preferably, the contact portion of the second conductive element 5 can be connected to the first power chip 2, the second power chip 4, and the third copper-clad region 10 respectively disposed on the second copper-clad region 9, so as to achieve electrical connection through its transition portion and the main body portion. Furthermore, the first chip group consisting of the first power chip 2 and the second power chip 4 disposed on the first copper-clad area 1 and the second chip group consisting of the first power chip 2 and the second power chip 4 disposed on the second copper-clad area 9 are electrically connected through the first conductive element 3 in a certain circuit topology. Since the lower surface of the power chip is soldered to the copper-clad area by solder pads or solder paste, and the upper surface of the power chip is soldered to the conductive element, the formed electrical connection relationship is more stable and reliable, which further enhances the heat capacity and transient current output capability of the first power chip 2 and the second power chip 4, thereby enhancing the current carrying capacity of the IGBT module. This solves the problem of high bonding difficulty in the prior art where the power terminals are connected to the chip in the form of bonding tape, thus avoiding the problem of chip damage caused by bonding tape deformation.

[0046] Preferably, the first conductive element 3 and / or the second conductive element 5 can be provided in a non-integral form. For example, the first conductive element 3 and / or the second conductive element 5 can have through holes in the main body to facilitate soldering of components below the first conductive element 3 / second conductive element 5 through the through holes. Furthermore, compared to using an aluminum wire bonding machine or a copper wire bonding machine to form current loops 12 on the plane where each copper-clad area of ​​the chipset is located, using copper busbar soldering makes the connection more stable and convenient.

[0047] Preferably, the first conductive element 3 and the second conductive element 5 can form spaces of different volumes relative to the circuit board where the IGBT module is located. It should be understood that the first conductive element 3 and the IGBT module below it have a smaller semi-enclosed space. Therefore, a momentary high temperature zone will be generated in the volume under a high current load. These high temperatures will cause airflow to rise, and the flow of low-temperature air from both sides to form convection is another important consideration for this design.

[0048] Therefore, in Figure 2 Below the transition portion of the second conductive element 5, above the copper-clad area between the two high-heat chips, an air inlet 13 is provided. Some of the heat from the air flowing through the copper-clad area is carried away by the copper-clad area and the copper second conductive element 5. Its temperature is slightly lower than that below the first conductive element 3 and near the surrounding chips, thus forming a temperature gradient and generating a chimney effect. This chimney effect is supported by the second conductive element 5, which has a higher heat dissipation capacity. Furthermore, the temperature difference of the air introduced from the four openings of different sizes creates a vortex rotating in one direction internally, further preventing the formation of localized hot spots and avoiding burnout. Preferably, the copper busbars are arranged in a stacked manner to form a hollowed-out spatial structure, increasing the contact area between the conductive elements and the external environment. This allows the heat generated by the devices on the IGBT module when current flows through them to be dissipated more quickly, improving the heat dissipation effect.

[0049] Preferably, the through-holes formed in the main body of the first conductive element 3 and / or the second conductive element 5 can also facilitate the generation of such a cyclone. The cyclone is achieved through the nesting of the first conductive element 3 and the second conductive element 5, particularly with the high-heat-generating chip located on one side below, and the low-heat-generating chipless or low-chip area located on the opposite side. An air barrier is formed between the two sides, for example, by fins extending towards the circuit board from the first conductive element 3 or the second conductive element 5, thereby creating a better airflow channel while facilitating the elimination of stray inductance.

[0050] Preferably, the current loop 12 formed by the IGBT module based on the above-mentioned electrical connection can flow from the first copper-clad region 1 through the second copper-clad region 9 to the third copper-clad region 10. The current can flow from the first copper-clad region 1 to the second copper-clad region 9 through the first conductive element 3, and from the second copper-clad region 9 to the third copper-clad region 10 through the second conductive element 5. Furthermore, based on the nested arrangement of the first conductive element 3 and the second conductive element 5, the first conductive element 3 and the second conductive element 5 can form a parallel relationship in space. Specifically, this parallel relationship can be that their main components are parallel to each other, and their transition components are parallel to each other. Based on the spatial structure of the first conductive element 3 and the second conductive element 5, the current direction flowing from the first copper-clad region 1 to the second copper-clad region 9 is approximately opposite to the current direction flowing from the second copper-clad region 9 to the third copper-clad region 10. Moreover, the two current directions are not coplanar in space, so that the magnetic fields formed by the two currents flowing in opposite directions in the middle region can cancel each other out, reducing the stray inductance of the current loop 12, resulting in low switching peak stress of the device, which can meet the requirements of high-frequency device applications. The middle region can be the common spatial intersection formed by the main body parts of the first conductive element 3 and the second conductive element 5 sweeping in opposite directions.

[0051] Preferably, the stacking scheme of the present invention has a stray inductance reduction effect of at least 50%, preferably up to 60%, and even more preferably up to 70%.

[0052] Preferably, in the prior art non-stacked solution, the inductance calculation formula is as follows:

[0053]

[0054] Among them, l d Let r be the length of current loop 12, r be the equivalent cross-sectional radius, and u be the length of current loop 12. o denoted as the permeability of the busbar material.

[0055] Furthermore, the length of the current loop 12 is typically the total length from the first power pin 8 through each chip on the copper-clad area to the third power pin 7; the equivalent cross-sectional radius is typically the radius of the equivalent circular conductor, such as the pin thickness; the busbar material is typically copper, with a permeability of .

[0056] Preferably, in the stacked configuration of the present invention, the inductance calculation formula is as follows:

[0057]

[0058] in, Let I be the flux linkage, b be the loop current, a be the copper busbar width, a be the copper busbar spacing, r be the equivalent cross-sectional radius, and u be the copper busbar width. o denoted as the permeability of the busbar material.

[0059] Furthermore, the copper busbar width refers to the length of the side of the main body of the copper busbar along the current direction when the conductive element is a copper busbar; the copper busbar spacing is the distance between the first conductive element 3 and the second conductive element 5, that is, the height of the middle region, which can be the common space intersection formed by the sweeping of the main bodies of the first conductive element 3 and the second conductive element 5 in mutually opposing directions; the equivalent cross-sectional radius is usually the radius of the equivalent circular conductor; the busbar material is usually copper, and its permeability is .

[0060] For example, for the non-stacked scheme in the accompanying drawings, its l d =0.1m, r=0.01m, the inductance L=44.91nH can be calculated; for the stacked scheme in the attached figure, b=0.15, a=0.01, r=0.01, the inductance L=13.71nH can be calculated. Thus, it can be calculated that compared with the non-stacked scheme of the prior art, the inductance of the stacked scheme of the present invention is reduced by 69.5%, which effectively verifies that by constructing stacked copper busbars with opposite but parallel current directions in space, the magnetic fields can be canceled out, thereby achieving the purpose of reducing the stray inductance of the current loop 12, and thus making the device switching peak stress small, which can meet the requirements of high-frequency device applications.

[0061] It is particularly important to emphasize here that, compared to measures to eliminate stray inductance between several IGBTs, the stray inductance within each IGBT is a more significant factor affecting performance. The circuit topology between several IGBTs is a well-established structural design, but it cannot be directly scaled down for improved internal design. Instead, extensive analysis and empirical formula calculations are required to find a stray inductance suppression scheme that balances high current and heat dissipation. In other words, the inductance calculation formula of this invention is not a common formula in the field, but rather the product of harmonizing numerous contradictory parameters—a fusion of art and technology.

[0062] Preferably, at least one encapsulation shell is disposed above the insulating plate 11 to form protection for the IGBT module. The height of the encapsulation shell is at least higher than the installation height of the second conductive element 5 to cover all devices on the IGBT module. Furthermore, since the encapsulation shell usually also has a certain height, and the stacked copper busbar of the present invention makes full use of this height, the dispersed devices on the IGBT module can be arranged more centrally, thereby reducing the overall volume of the encapsulation structure and increasing the power supply density of the IGBT module.

[0063] The IGBT packaging structure in the above embodiments can also be applied to the field of high-frequency IGBT technology. Specifically, according to another specific embodiment of this application, this application can also provide a vehicle power conversion device that includes the IGBT packaging structure in the above embodiments. By employing the IGBT packaging structure in the above embodiments, ultra-low stray inductance of the IGBT module is achieved, and the operational safety of the IGBT module is enhanced. While reducing operational redundancy, high-performance output of the IGBT module is realized.

[0064] Preferably, in practical applications, the first power chip 2 and the second power chip 4 of the IGBT module of this application can be configured as either a half-bridge circuit topology or a full-bridge circuit topology, depending on actual needs.

[0065] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, features introduced by "preferredly" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. An IGBT packaging structure, characterized in that, The IGBT package structure includes an insulating plate (11) with a flat structure. Several copper-plated areas are provided on one side of the insulating plate (11), and the copper-plated areas are electrically connected to each other through conductive components. The first copper-clad area (1) with the first power pin (8) is electrically connected to the second copper-clad area (9) with the second power pin (6) through the first conductive element (3). The second copper-clad area (9) is electrically connected to the third copper-clad area (10) with the third power pin (7) through the second conductive element (5). The first conductive element (3) and the second conductive element (5) are copper busbars; a chip group consisting of a first power chip (2) and a second power chip (4) is provided on the copper-plated area, wherein the first chip group is formed in the first copper-plated area (1) and the second chip group is formed in the second copper-plated area (9); One side of the first conductive element (3) is connected to the first power chip (2) and the second power chip (4) of the first chipset respectively, and the other side is connected to the second copper-plated area (9); one side of the second conductive element (5) is connected to the first power chip (2) and the second power chip (4) of the second chipset respectively, and the other side is connected to the third copper-plated area (10); The first conductive element (3) and the second conductive element (5) are arranged in a nested manner, such that the space formed by one conductive element is covered by the space formed by the other conductive element.

2. The IGBT packaging structure according to claim 1, characterized in that, Both the first conductive element (3) and the second conductive element (5) include a contact portion, a transition portion and a main body portion. The contact portion is a part of the conductive element that contacts the corresponding copper-clad area or power chip. One side of the transition portion is connected to the contact portion and the other side is connected to the main body portion.

3. The IGBT packaging structure according to claim 2, characterized in that, The main body portions of the first conductive element (3) and the second conductive element (5) are arranged in a manner that is not coplanar with the corresponding copper-clad area and the power chip, so that when the main body portion is projected along the direction toward the insulating plate, it sweeps to form a three-dimensional space corresponding to different conductive elements.

4. The IGBT packaging structure according to claim 2 or 3, characterized in that, The first conductive element (3) nested within the second conductive element (5) does not contact the second conductive element (5) on the outside, and an electrical gap is provided between the main body parts of the first conductive element (3) and the second conductive element (5) based on the power supply voltage.

5. The IGBT packaging structure according to claim 2 or 3, characterized in that, The first conductive element (3) and the second conductive element (5) are configured at least in a manner that increases the degree of overlap of the projected shapes of their main parts, wherein the degree of overlap of the projected shapes is the size of the intersection of the shapes of the main parts of the first conductive element (3) and the second conductive element (5) projected onto the insulating plate in the direction toward the insulating plate.

6. The IGBT packaging structure according to any one of claims 1 to 3, characterized in that, The first conductive element (3) and / or the second conductive element (5) are arranged in a non-integral form to complete the welding work through the through holes opened on the first conductive element (3) and / or the second conductive element (5).

7. The IGBT packaging structure according to any one of claims 1 to 3, characterized in that, An encapsulation shell with a height at least higher than the setting height of the second conductive element (5) is disposed above the insulating plate (11).

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