A high-voltage high-power crimping device packaging structure

Abstract

The application discloses a high-voltage and high-power crimping device packaging structure and relates to the technical field of power semiconductor device packaging. Each chip subunit corresponds to a conduction subunit; the collector and the emitter are respectively located at the upper end and the lower end of a tube shell, and the collector, the tube shell and the emitter form a sealed shell; the chip unit and the PCB board are both located in the sealed shell, each chip subunit is used for contacting the PCB board, one end of the PCB board contacts the gate electrode, and the other end of the gate electrode extends out of the sealed shell; when pressure is applied to the collector, one end of the chip subunit and one end of the spring subunit can both contact the collector, and the other end of the chip subunit can contact one end of the conduction subunit; the other end of the conduction subunit and the other end of the spring subunit are respectively connected with the emitter. The application can not only realize effective balance of the pressure, the junction temperature and the current of each chip in the device, but also realize failure short circuit of the device and improve surge and short circuit capacity.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor device packaging technology, and is mainly used to guide the packaging structure design of high-voltage, high-power press-fit devices. In particular, it relates to a high-voltage, high-power press-fit device packaging structure that can be applied to Si-based IGBTs or MOSFETs, SiC MOSFETs or other semiconductor devices. Background Technology

[0002] Power semiconductor devices are the "core" of various power electronic devices, and their characteristics, capacity, and reliability directly affect the performance of the entire device. In recent years, the application of high-voltage, high-power IGBT devices in power systems, especially press-fit packaging structures, has led to increasingly larger system capacities, such as 4500V, 3000A devices. Future power grid development places even higher demands on the capacity and reliability of press-fit IGBTs, such as the need to develop 4500V 5000A or even 10000A devices. Currently, all research institutions and companies have developed two different technical approaches: direct contact hard press-fit and spring contact elastic press-fit. Both packaging methods have their advantages and disadvantages, and since a perfect packaging solution has not yet been found, these two packaging methods will coexist for a long time.

[0003] The hard-press packaging structure directly connects the components together by applying external pressure to two copper electrodes, forming an electrical and thermal path. Therefore, hard-pressed devices have low parasitic parameters, current flows directly from the collector copper to the emitter copper, and the gate is connected to the PCB via a pin, resulting in low gate circuit parasitic parameters. Furthermore, hard-pressed devices have double-sided heat dissipation, leading to very low thermal resistance, low operating junction temperature, strong surge and short-circuit resistance, and fault-tolerant short-circuit characteristics. Fail-bridging short-circuit characteristics are of paramount concern in flexible DC transmission and are the most important protection mechanism for converter valves. When a component fails, a short-circuit path can be directly formed without affecting the operation of the entire device, allowing it to operate for extended periods until replacement during the following year's maintenance, significantly improving system reliability and reducing operating costs. However, because hard-pressed connections involve direct contact, they cannot absorb the expansion caused by heat during actual operation, resulting in uneven pressure distribution between the chips. This leads to changes in contact resistance and thermal resistance, i.e., strong thermal coupling. The presence of thermal coupling results in uneven distribution of current, temperature, and pressure among the chips inside a hard-pressed IGBT device. Often, the outer chips experience lower pressure, higher junction temperature, and higher current, leading to reduced reliability. This is the most critical and critical issue that hard-press packaging needs to address.

[0004] Flexible press-fit devices connect the chip to external electrodes using springs, effectively solving the aforementioned thermal coupling problem. The springs effectively absorb the thermal expansion of each chip, resulting in relatively uniform pressure, current, and temperature across the chips. However, due to the springs, only one side of the device has good thermal conductivity, meaning relatively high thermal resistance and parasitic parameters. Asymmetry in the gate layout leads to inconsistent dynamic characteristics among the chips within the device, particularly inconsistent gate signals, which can cause uneven current distribution. Furthermore, the spring structure limits the device's ability to withstand long-term short-circuit failures, requiring extremely stringent conditions for a short-term short-circuit failure. Another potential safety hazard of flexible press-fit devices is their lower explosion-proof capability compared to rigid press-fit devices; like welded modules, they lack a completely sealed environment. Therefore, flexible press-fit devices are essentially welded modules, only changing the current and installation method through press-fitting, making series application of modules easier.

[0005] These two technical approaches also share a common feature: they require significant mechanical pressure (approximately 1.2 kN / cm²). 2 To ensure proper contact between the chip and the gate oxide layer, the chip is subjected to extremely high mechanical stress. To effectively prevent damage to the chip structure, especially the gate oxide layer, chips used in press-fit packaging typically require special treatment. For example, the surface metal layer is much thicker than that of chips used in conventional soldering (generally about 50μm for press-fit chips and about 5μm for soldered chips). Additionally, some manufacturers add a special protective layer over the gate oxide layer to prevent pressure damage to the gate. This drastically increases the cost of the chip. If the applied pressure could be reduced, using chips from conventional soldering packaging could significantly lower the current cost. Summary of the Invention

[0006] The purpose of this invention is to provide a high-voltage, high-power press-fit device packaging structure that can effectively balance the pressure, junction temperature, and current of each chip inside the high-voltage, high-power press-fit device.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] This invention provides a high-voltage, high-power press-fit device packaging structure, including an electrode unit, a PCB board, a gate electrode, a chip unit, a support frame, and a housing;

[0009] The chip unit includes a chip subunit, a spring subunit, and a conductive subunit, and each chip subunit corresponds to one of the conductive subunits;

[0010] The electrode unit includes a collector and an emitter, the collector and the emitter being located at the upper end and lower end of the tube shell, respectively, and the collector, the tube shell and the emitter forming a sealed housing;

[0011] The chip unit, the support frame, and the PCB board are all located within the sealed housing. The support frame has several symmetrical partitions, each partition having a first mounting hole matching the conductive subunit and a second mounting hole matching the spring subunit. The PCB board is disposed on the support frame, and each chip subunit is used to contact the PCB board. The PCB board contacts one end of the gate electrode, and the other end of the gate electrode extends out of the sealed housing. When pressure is applied to the collector, one end of the chip subunit and one end of the spring subunit can contact the collector, and the other end of the chip subunit can contact one end of the conductive subunit. The other ends of the conductive subunit and the spring subunit are respectively connected to the emitter.

[0012] Preferably, when the collector is not under pressure, the height of the spring subunit is greater than the sum of the heights of the chip subunit and the conductive subunit.

[0013] Preferably, the chip sub-unit includes a chip, an upper conductive sheet, a lower conductive sheet, and a gate spring pin. One end of the upper conductive sheet is used to contact the collector. The chip is located between the upper conductive sheet and the lower conductive sheet, and both ends of the chip are connected to the other end of the upper conductive sheet and one end of the lower conductive sheet respectively through a sintering layer. One end of the gate spring pin is connected to the chip, and the other end of the gate spring pin is used to contact the PCB board. The other end of the lower conductive sheet is used to contact one end of the conductive sub-unit.

[0014] Preferably, the chip sub-unit further includes a chip frame, the chip, the upper conductive sheet and the lower conductive sheet are respectively connected to the chip frame, the other end of the gate spring pin extends out of the chip frame and is used to contact the PCB board, and one end of the conductive sub-unit extends into the chip frame and is used to contact the other end of the lower conductive sheet;

[0015] The upper conductive sheet and the lower conductive sheet are conductive sheets, and the sintered layer is nano-silver.

[0016] Preferably, the spring subunit includes an insulating pad, a disc spring base, a disc spring plate, and a disc spring guide rail. One end of the insulating pad is used to contact the collector electrode, one end of the disc spring base is in contact with the other end of the insulating pad, one end of the disc spring guide rail is connected to the other end of the disc spring base, and the other end of the disc spring guide rail is connected to the emitter electrode. The disc spring plate is sleeved on the disc spring guide rail. Disc spring pads are provided between the disc spring base and the disc spring plate, and between the disc spring plate and the emitter electrode. The disc spring pad between the disc spring plate and the emitter electrode is in contact with the emitter electrode.

[0017] Preferably, the conductive subunit includes a base, a guide rail, and a conductive sheet. One end of the base is used to contact the chip subunit, one end of the guide rail is connected to the other end of the base, the conductive sheet is sleeved on the guide rail, one end of the conductive sheet is in contact with the other end of the base, and the other end of the conductive sheet and the other end of the guide rail are both connected to the emitter.

[0018] Preferably, the housing is a ceramic housing with a stacked structure, the gate electrode passes through the sidewall of the housing, and the gate electrode is sealed to the housing.

[0019] The sealed housing is used to fill nitrogen gas.

[0020] Preferably, the PCB board includes an insulating base plate and several copper-clad layers. The insulating base plate is used to fix the integrated circuit. The position of each copper-clad layer corresponds to the position of each chip sub-unit. Each chip sub-unit can contact one of the copper-clad layers.

[0021] Preferably, there are gaps between the support frame and the conductive subunit and the spring subunit, respectively. The support frame is provided with a support protrusion, which passes through the positioning hole on the PCB board and is used to contact the collector.

[0022] When the current collector is not under pressure, the height of the support frame is lower than the height of the spring subunit.

[0023] Preferably, there are several chip units, and the several chip units are arranged symmetrically.

[0024] Each of the chip units includes a spring subunit, a plurality of chip subunits and a plurality of conductive subunits, wherein the chip subunits are symmetrically arranged around the spring subunit.

[0025] The present invention achieves the following technical effects compared to the prior art:

[0026] The collector of this invention is used to bear external mechanical pressure and serves as a current conduction path and heat transfer path; the collector, emitter, and shell form a sealed environment for the entire device, protecting the chip from environmental influences; the spring subunit is used to share the mechanical pressure applied to the chip subunit; the conductive subunit is used to support the chip subunit to form a good conductive path and thermal contact. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the packaging structure of the high-voltage, high-power crimping device of the present invention;

[0029] Figure 2 This is a schematic diagram of a chip subunit of the present invention;

[0030] Figure 3 This is a schematic diagram of the spring subunit of the present invention;

[0031] Figure 4 This is a schematic diagram of the chip sub-unit and conductive sub-unit of the present invention;

[0032] Figure 5 This is a schematic diagram of the PCB board of the present invention;

[0033] Figure 6 This is a schematic diagram of the support frame of the present invention;

[0034] Figure 7 This is a schematic diagram of the casing of the present invention;

[0035] Wherein: 1: Electrode unit, 1-1: Collector, 1-2: Emitter, 1-3: Flange;

[0036] 2-Chip sub-unit, 2-1: Chip, 2-2: Upper conductive sheet, 2-3: Lower conductive sheet, 2-4: Gate spring pin, 2-5: Chip frame, 2-6: Nano silver layer;

[0037] 3: Spring subunit; 3-1: Insulating pad; 3-2: Disc spring guide rail; 3-3: Disc spring base; 3-4: Disc spring washer; 3-5: Disc spring sheet;

[0038] 4: Conductive subunit; 4-1: Base; 4-2: Guide rail; 4-3: Conductive sheet;

[0039] 5: PCB board, 5-1: Insulating base plate, 5-2: Copper cladding layer, 5-3: First through hole, 5-4: Second through hole;

[0040] 6: Support frame; 6-1: First mounting hole; 6-2: Second mounting hole; 6-3: Support protrusion;

[0041] 7: Tube shell;

[0042] 8: Gate electrode. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The purpose of this invention is to provide a high-voltage, high-power press-fit device packaging structure that can effectively balance the pressure, junction temperature, and current of each chip inside the high-voltage, high-power press-fit device.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figures 1 to 7 As shown: This embodiment provides a high-voltage, high-power press-fit device packaging structure, which can be used for high-voltage, high-power IGBT devices, and can also be applied to SiC MOSFETs or double-sided heat dissipation modules for electric vehicles. This embodiment is not limited to IGBT chips, and can also be used for packaging other types of chips. The high-voltage, high-power press-fit device packaging structure of this embodiment includes an electrode unit 1, a PCB board 5, a gate electrode 8, a chip unit, a housing 7, and a support frame 6.

[0047] The chip unit includes a chip subunit 2, a spring subunit 3, and a conductive subunit 4, with each chip subunit 2 corresponding to a conductive subunit 4.

[0048] Electrode unit 1 includes collector 1-1 and emitter 1-2. Collector 1-1 and emitter 1-2 are located at the upper end and lower end of tube shell 7, respectively. Collector 1-1, tube shell 7 and emitter 1-2 form a sealed shell. The sealed shell is filled with nitrogen gas to ensure a stable internal environment and for internal insulation.

[0049] The chip unit, support frame 6 and PCB board 5 are all located in the sealed housing. The PCB board 5 is set on the support frame 6. Each chip sub-unit 2 is in contact with the PCB board 5. The PCB board 5 is in contact with one end of the gate electrode 8. The other end of the gate electrode 8 extends out of the sealed housing.

[0050] When pressure is applied to the collector 1-1, one end of the chip sub-unit 2 and one end of the spring sub-unit 3 can contact the collector 1-1, and the other end of the chip sub-unit 2 can contact one end of the conductive sub-unit 4.

[0051] The other end of the conductive subunit 4 and the other end of the spring subunit 3 are respectively connected to the emitter 1-2, and a heat exchange plate is provided on the emitter 1-2 side to absorb heat. This embodiment can meet the requirements of high voltage DC system and has extremely high current and thermal performance.

[0052] In this embodiment, there are several chip units, which are symmetrically arranged. Preferably, there are four chip units symmetrically arranged. In other embodiments, there can be one, two, or six chip units.

[0053] In this embodiment, each chip unit includes a spring subunit 3, eight chip subunits 2 and eight conductive subunits 4, with the eight chip subunits 2 arranged symmetrically around the spring subunit 3.

[0054] In this embodiment, when the collector 1-1 is not under pressure, the height of the spring subunit 3 is greater than the sum of the heights of the chip subunit 2 and the conductive subunit 4, while the height of the support frame 6 is lower than the height of the spring subunit 3. The greater height of the spring subunit 3 ensures a higher clamping force during device use.

[0055] In this embodiment, electrode unit 1 serves three functions: bearing external mechanical pressure, acting as a current conduction path, and a heat transfer path. Electrode unit 1 also includes flanges 1-3 corresponding to collector 1-1 and emitter 1-2. Collector 1-1 directly contacts the upper conductive plate 2-2 of chip sub-unit 2, bearing the mechanical pressure, acting as a current conduction path, and a heat transfer path. Emitter 1-2 contacts spring sub-unit 3 and conductive sub-unit 4, bearing the mechanical pressure and acting as a current conduction path, with very little heat passing through here. Flanges 1-3 corresponding to collector 1-1 and emitter 1-2 are connected to the flanges at both ends of the casing 7 by cold pressure welding, forming a sealed environment for the entire device and protecting chip 2-1 from environmental influences.

[0056] In this embodiment, chip subunit 2 is the core of the entire device, performing its core functions. Chip subunit 2 includes chip 2-1, upper conductive sheet 2-2, lower conductive sheet 2-3, gate spring pin 2-4, and chip frame 2-5. Chip 2-1 is used to implement all the functions of the device and requires good electrical and thermal connections to ensure basic characteristics and reliability. Chip 2-1, upper conductive sheet 2-2, and lower conductive sheet 2-3 are respectively connected to chip frame 2-5. One end of upper conductive sheet 2-2 is used to contact collector 1-1. Chip 2-1 is located between upper conductive sheet 2-2 and lower conductive sheet 2-3. Upper conductive sheet 2-2 and lower conductive sheet 2-3 are conductive sheets 4-3. The high thermal conductivity, high electrical conductivity, high Young's modulus, and low coefficient of thermal expansion of conductive sheet 4-3 can effectively... External pressure is evenly transmitted to chip 2-1, effectively protecting chip 2-1. Both upper conductive sheet 2-2 and lower conductive sheet 2-3 are sintered using technology, such as a nano-silver layer 2-6, to achieve electrical, thermal, and mechanical connection with chip 2-1. Gate spring pin 2-4 is the gate signal line of chip 2-1. One end of gate spring pin 2-4 is connected to chip 2-1, and the other end of gate spring pin 2-4 extends out of chip frame 2-5 and contacts PCB board 5 through pressure to achieve electrical connection, which is used for external signals to directly drive chip 2-1. One end of base 4-1 of conductive subunit 4 extends into chip frame 2-5 and is used to contact the other end of lower conductive sheet 2-3.

[0057] In this embodiment, the chip frame 2-5 is made of plastic. The chip frame 2-5, through a molding process, encapsulates the chip 2-1, upper conductive sheet 2-2, lower conductive sheet 2-3, and gate spring pin 2-4 into a complete sub-unit. This effectively protects the chip 2-1 from environmental influences and improves its voltage withstand capability. Furthermore, the sub-unit approach significantly reduces design and manufacturing costs and improves testing and packaging efficiency. The nano-silver sintered layer connects the chip 2-1 to the upper conductive sheet 2-2 and lower conductive sheet 2-3 via a sintering process. This technology greatly reduces the processing requirements of each component. By adjusting the thickness of the nano-silver, the height of the chip sub-unit 2 can be easily matched. Simultaneously, the high thermal conductivity, electrical conductivity, and reliability of the nano-silver material significantly reduce the voltage drop and thermal resistance of the chip sub-unit 2, improving its reliability.

[0058] In this embodiment, the core function of the spring subunit 3 is to bear external mechanical pressure. It is neither electrically nor thermally conductive, ensuring good contact between the components of the conductive subunit 4 inside the device and between the device and the heat sink. The spring subunit 3 includes an insulating pad 3-1, a disc spring base 3-3, a disc spring plate 3-5, and a disc spring guide rail 3-2. The insulating pad 3-1 is made of epoxy resin and bears mechanical pressure and provides insulation, isolating the corresponding current and heat transfer paths. It needs to withstand significant mechanical pressure. One end of the insulating pad 3-1 is used to contact the collector 1-1. One end of the disc spring base 3-3 contacts the other end of the insulating pad 3-1, and one end of the disc spring base 3-3 is located in the slot of the insulating pad 3-1. The size of one end of the disc spring base 3-3 matches the size of the slot of the insulating pad 3-1, achieving self-locking limitation. The disc spring guide rail 3-2... One end of the disc spring is connected to the other end of the disc spring base 3-3, and the other end of the disc spring guide rail 3-2 is connected to the emitter 1-2. The disc spring 3-5 is sleeved on the disc spring guide rail 3-2. The disc spring guide rail 3-2 is used to limit or constrain the disc spring 3-5 to move only in the axial direction, completing the application and release of external mechanical pressure. Disc spring washers 3-4 are provided between the disc spring base 3-3 and the disc spring 3-5, and between the disc spring 3-5 and the emitter 1-2. The disc spring washers 3-4 between the disc spring 3-5 and the emitter 1-2 are in contact with the emitter 1-2. The disc spring washers 3-4 are used to convert the line contact of the disc spring 3-5 into a surface contact, improving the pressure balance. The spring subunit 3 is used to share the mechanical pressure applied to the chip subunit 2. When the mechanical pressure reaches the specified displacement of the spring subunit 3, the excess pressure is borne by the support frame 6 to effectively protect the chip subunit 2. The purpose of this move is to greatly reduce the pressure on chip 2-1, so that chip 2-1 with conventional soldered module packaging can meet the requirements, thus greatly reducing R&D costs and time.

[0059] In this embodiment, the disc spring 3-5 achieves the effect of a disc spring through its own deformation. Stacking two disc springs 3-5 doubles the stroke without changing the force. When increased pressure is required, the two can be stacked in parallel, with two disc spring guide rails 3-2 provided accordingly. When external pressure is applied to the collector 1-1 and emitter 1-2, the pressure is transmitted through the spring subunit 3. At this time, the disc spring 3-5 will deform and generate displacement until the specified displacement is reached. Then, the collector 1-1 directly presses on the support frame 6 to absorb the excess pressure, and the disc spring 3-5 no longer deforms.

[0060] In this embodiment, the conductive subunit 4 is mainly used to support the chip subunit 2 to form a good conductive path and thermal contact, and the required pressure is much less than that of the spring subunit 3. The conductive subunit 4 includes a base 4-1, a guide rail 4-2, and a conductive sheet 4-3. One end of the base 4-1 extends into the chip frame 2-5, enabling the base 4-1 to engage with the chip frame 2-5, and also serves to contact the lower conductive sheet 2-3 of the chip subunit 2. The base 4-1 has two functions: one is to limit and lock the conductive subunit 4, and to apply and release some external mechanical pressure; the other is to provide pressure transition, making the pressure transmitted to the chip subunit 2 more uniform. One end of the guide rail 4-2 is connected to the other end of the base 4-1. The conductive sheet 4-3 is fitted onto the guide rail 4-2, with one end of the conductive sheet 4-3 contacting the other end of the base 4-1. Both the other ends of the conductive sheet 4-3 and the guide rail 4-2 are connected to the emitter 1-2. The guide rail 4-2 functions similarly to the disc spring guide rail 3-2, limiting the conductive sheet 4-3 to axial displacement and deformation. The conductive sheet 4-3 consists of two U-shaped copper sheets. The conductive sheet 4-3 is formed by its own shape... The conductive sheet 4-3 achieves the effect of a spring, allowing for long displacements and small pressure changes. It has three core functions: First, it serves as the conductive path for chip sub-unit 2, allowing current to flow from collector 1-1 through chip sub-unit 2 and then through conductive sheet 4-3 to emitter 1-2. This cross-sectional area needs to consider the current carrying capacity after a short circuit due to device failure. Second, through its large deformation, it provides a certain degree of mechanical pressure to chip sub-unit 2, ensuring good contact between components in the branch containing chip sub-unit 2, reducing the device's saturation voltage drop and thermal resistance. Since the large mechanical pressure is borne by spring sub-unit 3 and excess pressure by support frame 6, the pressure applied to conductive sub-unit 4 only needs to ensure that the contact resistance and thermal resistance of each component are within a certain range; a separately customized high-pressure-resistant press-fit chip 2-1 is not required. Finally, the large deformation function of conductive sheet 4-3 effectively absorbs the thermal expansion effect caused by the self-heating of chip 2-1, resulting in an extremely uniform pressure distribution across all chips 2-1.

[0061] In this embodiment, the stacked PCB board 5 is used to apply gate signals to all chips 2-1 within the press-fit device, so that the gate signals reach all chips 2-1 synchronously. The PCB board 5 is matched with the chip units and has a symmetrical layout, which can ensure the current uniformity of each chip 2-1. Specifically, the PCB board 5 includes an insulating base plate 5-1 and several copper-clad layers 5-2. The insulating base plate 5-1 is used to fix the integrated circuit, provide mechanical support for the circuit, achieve electrical insulation for electrical connections, and provide the required electrical characteristics. The position of each copper-clad layer 5-2 corresponds to the position of each chip sub-unit 2. The gate spring pins 2-4 of each chip sub-unit 2 can contact a copper-clad layer 5-2. The PCB board 5 is also provided with a compensation resistor, which is connected in series with the copper-clad layers 5-2. By adjusting the size of the compensation resistor, the time it takes for the voltage on it to reach the ideal value is changed. When the gate spring pin 2-4 touches the copper layer 5-2, applying pressure makes the contact between the gate spring pin 2-4 more secure. All gate signals pass through the copper layer 5-2 and converge at one end of the PCB board 5. The PCB board 5 is fixed to the gate electrode 8 with screws, and the gate electrode 8 leads out the gate signal through the housing 7. The thickness of the PCB board 5 is 0.8mm. While ensuring the reliability of the drive signal transmission, a smaller size is chosen to reduce space. The shape of the PCB board 5 matches the support frame 6, which restricts the position of the PCB board 5 within the device and ensures the stability of the gate signal. The parasitic inductance on the PCB board 5 is calculated using simulation software. By designing corresponding compensation resistors for gate signals at different distances, the current distribution is improved, so that the external gate signal is distributed to each chip 2-1 almost simultaneously, ensuring that all chips 2-1 can switch gate signal switching synchronously.

[0062] In this embodiment, the support frame 6 is made of epoxy resin. The support frame 6 has several symmetrical partitions. Each partition has a first mounting hole 6-1 that matches the conductive subunit 4 and a second mounting hole 6-2 that matches the spring subunit 3. The PCB board 5 has a first through hole 5-3 at the corresponding position of the first mounting hole 6-1 and a second through hole 5-4 at the corresponding position of the second mounting hole 6-2. There are gaps between the support frame 6 and the conductive subunit 4 and the spring subunit 3. The support frame 6 has a support protrusion 6-3. The PCB board 5 is placed on the support frame 6, and the support protrusion 6-3 passes through the positioning hole on the PCB board 5. The support protrusion 6-3 is used to contact the collector 1-1. The support frame 6 is mainly used to bear excess pressure. In cooperation with the spring subunit 3, when pressure is applied, the spring subunit 3 will first bear part of the pressure. Then the collector 1-1 will contact the conductive subunit 4. When the conductive subunit 4 reaches the specified displacement, the excess mechanical stress will be borne by the support frame 6 to protect the internal structure from mechanical damage. Meanwhile, the structure of the support frame 6 can restrict the positions of the spring subunit 3, the conductive subunit 4, and the PCB board 5, preventing displacement contact between them. Furthermore, epoxy resin possesses excellent mechanical properties, high resistivity, and low thermal conductivity. The support frame 6 is matched with the chip unit, and the support frame 6 is provided with symmetrical partitions; in this embodiment, four symmetrical partitions are preferred, each corresponding to one chip unit. This reduces the thermo-mechanical coupling effect within the device, ensuring the stability of the device.

[0063] In this embodiment, the housing 7 is a ceramic housing with a stacked structure. Increasing the creepage distance effectively prevents breakdown and short circuits between the collector 1-1 and the emitter 1-2. The gate electrode 8 passes through the sidewall of the housing 7 and is sealed to the housing 7. The housing 7 has high mechanical strength, good insulation performance, high electrical strength, and high temperature resistance. As the outermost structure of the device, it can effectively reduce external interference to the internal structure of the device and play a supporting and protective role.

[0064] When the device is turned on, the current flows from the collector 1-1 through the chip sub-unit 2, through the base 4-1 in the conductive sub-unit 4 and the two stacked conductive plates 4-3, and then to the emitter 1-2.

[0065] Assuming the emitter 1-2 is fixed, the main pressure transmission path during device use is as follows: When pressure is applied to the collector 1-1, the collector 1-1 contacts the chip sub-unit 2 more tightly, and the contact thermal resistance between them decreases. At this time, the chip sub-unit 2 transmits pressure downwards, making tighter contact with the base 4-1 in the conductive sub-unit 4. The base 4-1 and the conductive sheet 4-3 are compressed and move downwards along the guide rail 4-2, pressing against the fixed emitter 1-2. Since the height of the designed spring sub-unit 3 is greater than that of the chip sub-unit 2 plus the conductive sub-unit 4, the collector 1-1 will only contact the spring sub-unit 3 after moving downwards a certain distance. When the collector 1-1 contacts the spring sub-unit 3, the chip sub-unit 2 and the conductive sub-unit 4 are in a compressed state. As the collector 1-1 continues to move downwards, it will drive the chip sub-unit 2, the conductive sub-unit 4, and the spring sub-unit 3 to move downwards together until the collector 1-1 touches the support frame 6 and stops moving. At this time, the entire device reaches its maximum compression, and the subsequent pressure will be mainly borne by the support frame 6.

[0066] The main heat path of the device during use: The heat source of the device mainly comes from the chip sub-unit 2, specifically the active area on chip 2-1. The heat flowing upward flows into the external heat exchange plate through the collector 1-1. This part is the main heat dissipation path. The support frame 6 is used to divide the inside of the device into four independent symmetrical sub-modules, which reduces the thermal coupling effect inside the device and ensures the stability of the device.

[0067] The gate signal circuit during device operation: A positive gate signal is applied to the gate electrode 8 extending from the side of the device housing 7, creating a voltage drop between it and the emitter 1-2, thus turning on the gate electrode 8. The gate voltage signal is transmitted to the position of each chip sub-unit 2 through the copper layer 5-2, and then to chip 2-1 through the gate spring pin 2-4. Compensation resistors are designed to improve current distribution, enabling the external gate signal to be distributed to each chip 2-1 almost simultaneously, ensuring that all chips 2-1 can switch their gate signals synchronously.

[0068] The high-voltage, high-power press-fit device packaging structure of this embodiment exhibits more uniform pressure and junction temperature distribution, resulting in a longer device lifespan. Compared to hard press-fit device packaging, the support frame 6 features symmetrical partitioning, which reduces internal thermo-mechanical coupling effects and makes the pressure and temperature distribution on the device surface more uniform.

[0069] The high-voltage, high-power press-fit device packaging structure of this embodiment requires less clamping force. Chip 2-1 adopts double-sided sintering technology, thereby reducing the clamping force required for chip sub-unit 2 and lowering the requirements for fixtures.

[0070] The high-voltage, high-power press-fit device packaging structure of this embodiment has lower thermal resistance. By inserting a thermal interface material, such as a nano-silver layer 2-6, into the interface between the collector 1-1 and the upper conductive sheet 2-2, the thermal resistance is further reduced, and the required clamping force can also be further reduced.

[0071] In this embodiment, the parasitic inductance of the gate electrode 8 circuit is small. The current distribution is improved by designing compensation resistors on the stacked PCB board 5, so that the external gate signal can be distributed to each chip 2-1 almost simultaneously, ensuring that all chips 2-1 can switch the gate signal switching in a relatively synchronized manner at the same time.

[0072] This embodiment is easy to install. Compared with the packaging of elastic compression devices, it separates the pressure absorption function and the conductivity function, using spring sub-unit 3 and conductivity sub-unit 4 respectively, thereby reducing a large number of springs, reducing material costs, and saving installation time.

[0073] This embodiment has a very high tolerance for uneven installation pressure. The displacement difference is absorbed by the disc spring 3-5 and the conductive sheet 4-3 to ensure the uniformity of pressure distribution.

[0074] This embodiment is safe to use. The support frame 6 can withstand excess pressure to protect the chip 2-1 from damage, and the casing 7 also has sufficiently strong mechanical and electrical protection functions.

[0075] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-voltage, high-power press-fit device packaging structure, characterized in that: It includes electrode units, PCB board, gate electrode, chip unit, support frame and casing; The chip unit includes a chip subunit, a spring subunit, and a conductive subunit, and each chip subunit corresponds to one of the conductive subunits; The electrode unit includes a collector and an emitter, the collector and the emitter being located at the upper end and lower end of the tube shell, respectively, and the collector, the tube shell and the emitter forming a sealed housing; The chip unit, the support frame, and the PCB board are all located in the sealed housing. The support frame is provided with several symmetrical partitions. Each partition has a first mounting hole that matches the conductive subunit and a second mounting hole that matches the spring subunit. The PCB board is disposed on the support frame. Each chip subunit is used to contact the PCB board. The PCB board contacts one end of the gate electrode, and the other end of the gate electrode extends out of the sealed housing. When pressure is applied to the collector, one end of the chip sub-unit and one end of the spring sub-unit can contact the collector, and the other end of the chip sub-unit can contact one end of the conductive sub-unit; the other end of the conductive sub-unit and the other end of the spring sub-unit are respectively connected to the emitter. When the collector is not under pressure, the height of the spring subunit is greater than the sum of the heights of the chip subunit and the conductive subunit, and the height of the support frame is lower than the height of the spring subunit. The spring subunit includes an insulating pad, a disc spring base, a disc spring plate, and a disc spring guide rail. One end of the insulating pad is used to contact the collector electrode. One end of the disc spring base is in contact with the other end of the insulating pad. One end of the disc spring guide rail is connected to the other end of the disc spring base, and the other end of the disc spring guide rail is connected to the emitter electrode. The disc spring plate is sleeved on the disc spring guide rail. Disc spring pads are provided between the disc spring base and the disc spring plate, and between the disc spring plate and the emitter electrode. The disc spring pad between the disc spring plate and the emitter electrode is in contact with the emitter electrode.

2. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: The chip subunit includes a chip, an upper conductive sheet, a lower conductive sheet, and a gate spring pin. One end of the upper conductive sheet is used to contact the collector. The chip is located between the upper conductive sheet and the lower conductive sheet, and both ends of the chip are connected to the other end of the upper conductive sheet and one end of the lower conductive sheet through sintering layers, respectively. One end of the gate spring pin is connected to the chip, and the other end of the gate spring pin is used to contact the PCB board. The other end of the lower conductive sheet is used to contact one end of the conductive subunit.

3. The high-voltage, high-power press-fit device packaging structure according to claim 2, characterized in that: The chip subunit also includes a chip frame. The chip, the upper conductive sheet, and the lower conductive sheet are respectively connected to the chip frame. The other end of the gate spring pin extends out of the chip frame and is used to contact the PCB board. One end of the conductive subunit extends into the chip frame and is used to contact the other end of the lower conductive sheet. The upper conductive sheet and the lower conductive sheet are conductive sheets, and the sintered layer is nano-silver.

4. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: The conductive subunit includes a base, a guide rail, and a conductive sheet. One end of the base is used to contact the chip subunit, one end of the guide rail is connected to the other end of the base, the conductive sheet is sleeved on the guide rail, one end of the conductive sheet is in contact with the other end of the base, and the other end of the conductive sheet and the other end of the guide rail are both connected to the emitter.

5. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: The casing is a ceramic casing with a stacked structure. The gate electrode passes through the side wall of the casing and is sealed to the casing. The sealed housing is used to fill nitrogen gas.

6. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: The PCB board includes an insulating base plate and several copper-clad layers. The insulating base plate is used to fix integrated circuits. The position of each copper-clad layer corresponds to the position of each chip sub-unit. Each chip sub-unit can contact one of the copper-clad layers.

7. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: There are gaps between the support frame and the conductive subunit and the spring subunit respectively. The support frame is provided with a support protrusion, which passes through the positioning hole on the PCB board and is used to contact the collector.

8. The high-voltage, high-power press-fit device packaging structure according to claim 1, characterized in that: The chip unit is a plurality of units, and the plurality of chip units are arranged symmetrically; Each of the chip units includes a spring subunit, a plurality of chip subunits and a plurality of conductive subunits, wherein the chip subunits are symmetrically arranged around the spring subunit.

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