Power device

Abstract

The utility model provides a power device. The power device comprises a bottom phase change vapor chamber; the bottom substrate is connected to the upper surface of the bottom phase change vapor chamber; the power chip is connected to the upper surface of the bottom substrate, and heat of the power chip can be transmitted to the bottom phase change vapor chamber through the bottom substrate; the heat conduction structure is connected to the upper surface of the power chip; the top substrate is connected to the upper surface of the heat conduction structure; and the top phase change vapor chamber is connected to the upper surface of the top substrate, and heat of the power chip can be transmitted to the top phase change vapor chamber through the heat conduction structure and the top substrate. According to the technical scheme, the problem that the packaging structure of the power device in the related technology is difficult to meet the heat dissipation requirement can be effectively solved.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor devices, and more particularly, to a power device. Background Art

[0002] Power semiconductor devices, as an important part of power electronics technology, are widely used in fields such as transportation, the automotive industry, and renewable energy power generation. Compared with silicon-based power modules, silicon carbide power modules usually have faster switching speeds and higher output powers, which result in higher power consumption and pose great challenges to thermal management. Currently, the main problem of high-power devices, especially third-generation semiconductor power devices, is still the failure problem caused by heat, and more than 70% of the failures are caused by heat. Therefore, optimizing module thermal management plays a crucial role in the development of silicon carbide power modules. In order to adapt to the excellent performance of silicon carbide power devices, advanced packaging technologies with low thermal resistance and high reliability are urgently needed.

[0003] The functions of power module packaging mainly include providing electrical connections, enhancing insulation performance, providing heat dissipation paths, and providing structural support, etc. The packaging process and packaging structure can directly affect the electrical performance, electromagnetic interference, and thermal performance of power modules.

[0004] Traditional packaging structures mainly include chips, bonding wires, double-sided copper-clad ceramic substrates, base plates, power terminals, housings, and potting adhesives, etc. The heat generated by chip losses is conducted to the radiator through structures such as double-sided copper-clad ceramic substrates and base plates. Due to the good heat insulation of the potting adhesive, the overall thermal resistance of the packaging module is relatively large. And due to the limitations of the packaging materials and the heat dissipation performance of external liquid-cooled radiators, the temperature distribution within the same material layer is uneven, and the heat is mainly concentrated near the heat source.

[0005] In addition, at the same rated voltage and current, the size of commercially available silicon carbide MOSFETs (metal-oxide-semiconductor field-effect transistors) is usually much smaller than that of silicon-based devices or silicon carbide IGBTs (insulated gate bipolar transistors). The reduction in chip area causes a sharp increase in the heat flux of the chip, further increasing the requirements for device heat dissipation.

[0006] Research has found that if the heat dissipation inside the power module is uneven, it will lead to uneven distribution of thermal stress inside the module, easily causing problems such as the peeling off of the solder layer, affecting the reliability of the module. Higher power density and smaller chip size result in more concentrated stress and strain, and the existing packaging structures still rely on traditional liquid-cooled radiators for heat dissipation, inevitably having problems such as poor heat dissipation performance and poor temperature uniformity. Summary of the Utility Model

[0007] The main purpose of the utility model is to provide a power device to solve the problem that the packaging structure of power devices in related technologies is difficult to meet the heat dissipation requirements.

[0008] To achieve the above object, the present utility model provides a power device, comprising: a bottom phase change heat spreader; a bottom substrate connected to the upper surface of the bottom phase change heat spreader; a power chip connected to the upper surface of the bottom substrate, and the heat of the power chip can be transferred to the bottom phase change heat spreader through the bottom substrate; a heat conduction structure connected to the upper surface of the power chip; a top substrate connected to the upper surface of the heat conduction structure; and a top phase change heat spreader connected to the upper surface of the top substrate, and the heat of the power chip can be transferred to the top phase change heat spreader through the heat conduction structure and the top substrate.

[0009] Further, the bottom phase change heat spreader includes a heat conduction housing having a vacuum chamber, a wick is provided on the inner side wall of the heat conduction housing, and a phase change medium is filled in the vacuum chamber.

[0010] Further, the heat conduction housing includes an evaporation half shell and a condensation half shell, the wick includes an evaporation wick layer provided on the evaporation half shell and a condensation wick layer provided on the condensation half shell, and the bottom substrate is connected to the evaporation half shell. Wherein, the bottom phase change heat spreader further includes a liquid guiding rib connected between the evaporation wick layer and the condensation wick layer, and the wick and the liquid guiding rib have a capillary structure; and / or, the bottom phase change heat spreader further includes a support column provided in the vacuum chamber and abutted against both the evaporation half shell and the condensation half shell.

[0011] Further, the phase change medium is deionized water, ethanol or acetone.

[0012] Further, the bottom phase change heat spreader and the bottom substrate are connected by soldering with a tin solder sheet; and / or, the power chip and the bottom substrate are sintered and connected by a nano silver paste; and / or, the heat conduction structure and the power chip and the top substrate are sintered and connected by a nano silver paste.

[0013] Further, a first conductive layer and a second conductive layer are spaced on the bottom substrate, a third conductive layer and a fourth conductive layer are spaced on the top substrate, the power chip includes an upper half-bridge switching chip provided on the first conductive layer and a lower half-bridge switching chip provided on the second conductive layer, the heat conduction structure includes a first metal heat conduction block connected between the upper half-bridge switching chip and the third conductive layer and a second metal heat conduction block connected between the lower half-bridge switching chip and the fourth conductive layer, and the power device further includes a third metal heat conduction block connected between the second conductive layer and the third conductive layer.

[0014] Further, the power device further includes an AC power terminal connected to the second conductive layer, a first DC power terminal connected to the first conductive layer, and a second DC power terminal connected to the fourth conductive layer. The AC power terminal is located between the first DC power terminal and the second DC power terminal, and the AC power terminal, the first DC power terminal, and the second DC power terminal extend in the same direction.

[0015] Further, the power device further includes an upper half-bridge diode chip disposed on the first conductive layer and in parallel with the upper half-bridge switch chip, and a lower half-bridge diode chip disposed on the second conductive layer and in parallel with the lower half-bridge switch chip. In the arrangement direction of the first conductive layer and the second conductive layer, the upper half-bridge switch chip and the lower half-bridge diode chip are correspondingly arranged, and the lower half-bridge switch chip and the upper half-bridge diode chip are correspondingly arranged.

[0016] Further, the power device further includes a fourth metal heat conducting block connected between the upper half-bridge diode chip and the third conductive layer, and a fifth metal heat conducting block connected between the lower half-bridge diode chip and the fourth conductive layer.

[0017] Further, a first source electrode is provided on the upper surface of the upper half-bridge switch chip. The first metal heat conducting block is located within the range of the first source electrode, and a first avoidance recess is provided on the first metal heat conducting block to expose a part of the first source electrode; and / or, a second source electrode is provided on the upper surface of the lower half-bridge switch chip. The second metal heat conducting block is located within the range of the second source electrode, and a second avoidance recess is provided on the second metal heat conducting block to expose a part of the second source electrode.

[0018] Further, a fifth conductive layer and a sixth conductive layer are further provided on the bottom substrate. The power device further includes a gate terminal connected to the fifth conductive layer and an auxiliary source terminal connected to the sixth conductive layer. The gate terminal and the auxiliary source terminal extend in a direction opposite to the extension direction of the AC power terminal. The fifth conductive layer is conductively connected to the upper surface of the upper half-bridge switch chip through a first conductive connection member, and the sixth conductive layer is conductively connected to the upper surface of the upper half-bridge switch chip through a second conductive connection member.

[0019] Applying the technical solution of the present utility model, the power device includes a bottom phase change heat sink, a bottom substrate, a power chip, a heat conduction structure, a top substrate, and a top phase change heat sink arranged in sequence from bottom to top. Among them, the power chip, the bottom substrate, and the bottom phase change heat sink form a downward heat transfer path, and the power chip, the heat conduction structure, the top substrate, and the top phase change heat sink form an upward heat transfer path. Thus, dual-path heat dissipation is achieved. Compared with the existing packaging structure of power devices, an upward heat dissipation path is added, which greatly improves the overall heat dissipation capacity of the device. In addition, the bottom phase change heat sink and the top phase change heat sink have a temperature equalization performance, which increases the heat dissipation area. Furthermore, the temperature difference within the same material layer inside the power device becomes smaller, reducing phenomena such as material fracture caused by uneven thermal stress distribution, reducing the thermal resistance, improving the overall heat dissipation performance of the power device, enhancing the service life and reliability of the power device, and enabling the power device to be applicable to high-temperature conditions. Therefore, the technical solution of this application can effectively solve the problem that the packaging structure of power devices in related technologies is difficult to meet the heat dissipation requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings forming a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments and descriptions thereof of the present utility model are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0021] Figure 1 A structural schematic diagram of the heat conduction of a power device in the prior art is shown;

[0022] Figure 2 A three-dimensional structural schematic diagram of an embodiment of a power device according to the present utility model is shown;

[0023] Figure 3 Shown is Figure 2 the exploded structural schematic diagram of the power device;

[0024] Figure 4 Shown is Figure 2 the side view schematic diagram of the bottom phase change heat sink of the power device;

[0025] Figure 5 Shown is Figure 4 the exploded structural schematic diagram of the bottom phase change heat sink;

[0026] Figure 6 Shown is Figure 4 the three-dimensional structural schematic diagram of the evaporation half shell of the bottom phase change heat sink of the power device;

[0027] Figure 7 Shown is Figure 4 the structural schematic diagram of the heat conduction of the bottom phase change heat sink of the power device;

[0028] Figure 8 shows Figure 2 a three-dimensional structural schematic diagram of a partial structure of a power device;

[0029] Figure 9 shows Figure 8 a top view schematic diagram of a power device with the top substrate removed;

[0030] Figure 10 shows Figure 9 a three-dimensional structural schematic diagram of a power device;

[0031] Figure 11 shows Figure 10 an enlarged view of area A of a power device;

[0032] Figure 12 shows Figure 10 an enlarged view of area B of a power device;

[0033] Figure 13 shows Figure 2 a bottom view schematic diagram of the top substrate of a power device;

[0034] Figure 14 shows Figure 8 a side view schematic diagram of a partial structure of a power device;

[0035] Figure 15 shows Figure 2 a top view schematic diagram of the upper half-bridge switching chip of a power device;

[0036] Figure 16 shows Figure 2 a bottom view schematic diagram of the upper half-bridge switching chip of a power device;

[0037] Figure 17 shows Figure 2 a schematic diagram of the circulating current loop of a power device.

[0038] Among them, the above-mentioned drawings include the following reference numerals:

[0039] 1, heat source; 2, material one; 3, material two;

[0040] 10, bottom phase change heat spreader; 11, heat conduction housing; 111, evaporation half shell; 112, condensation half shell; 12, vacuum chamber; 13, liquid guiding rib; 131, first surrounding rib; 132, second surrounding rib; 14, support column; 15, wick; 151, evaporation wick layer; 152, condensation wick layer;

[0041] 20. Bottom substrate; 21. First conductive layer; 22. Second conductive layer; 23. Fifth conductive layer; 24. Sixth conductive layer; 25. Seventh conductive layer; 26. Eighth conductive layer;

[0042] 30. Power chip; 31. Upper half-bridge switch chip; 311. First source electrode; 312. Gate electrode; 313. Drain electrode; 32. Lower half-bridge switch chip; 321. Second source electrode;

[0043] 40. Heat conduction structure; 41. First metal heat conduction block; 411. First avoidance recess; 42. Second metal heat conduction block; 421. Second avoidance recess;

[0044] 50. Top substrate; 51. Third conductive layer; 52. Fourth conductive layer;

[0045] 60. Top phase change heat spreader;

[0046] 71. Third metal heat conduction block;

[0047] 81. AC power terminal; 82. First DC power terminal; 83. Second DC power terminal; 84. Gate terminal; 85. Auxiliary source terminal; 86. Gate terminal; 87. Auxiliary source terminal;

[0048] 91. Upper half-bridge diode chip; 92. Lower half-bridge diode chip;

[0049] 101. Fourth metal heat conduction block; 102. Fifth metal heat conduction block;

[0050] 201. First conductive connection member; 202. Second conductive connection member; 203. Third conductive connection member; 204. Fourth conductive connection member;

[0051] 300. Housing; 301. Top half-shell; 302. Bottom half-shell. Detailed implementation manners

[0052] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present utility model and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the scope of protection of the present utility model.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0055] As Figure 2 and Figure 3 As shown, the present application provides a power device. Embodiments of the power device of the present application include: a bottom phase change heat sink 10, a bottom substrate 20, a power chip 30, a heat conduction structure 40, a top substrate 50, and a top phase change heat sink 60. Among them, the bottom substrate 20 is connected to the upper surface of the bottom phase change heat sink 10; the power chip 30 is connected to the upper surface of the bottom substrate 20, and the heat of the power chip 30 can be transferred to the bottom phase change heat sink 10 through the bottom substrate 20; the heat conduction structure 40 is connected to the upper surface of the power chip 30; the top substrate 50 is connected to the upper surface of the heat conduction structure 40; the top phase change heat sink 60 is connected to the upper surface of the top substrate 50, and the heat of the power chip 30 can be transferred to the top phase change heat sink 60 through the heat conduction structure 40 and the top substrate 50.

[0056] Applying the technical solution of this embodiment, the power device includes a bottom phase change heat spreader 10, a bottom substrate 20, a power chip 30, a heat conduction structure 40, a top substrate 50, and a top phase change heat spreader 60 arranged in sequence from bottom to top. Among them, the power chip 30, the bottom substrate 20, and the bottom phase change heat spreader 10 form a downward heat transfer path, and the power chip 30, the heat conduction structure 40, the top substrate 50, and the top phase change heat spreader 60 form an upward heat transfer path. Thus, dual-path heat dissipation is achieved. Compared with the existing packaging structure of power devices, an upward heat dissipation path is added, greatly improving the overall heat dissipation capacity of the device. In addition, the bottom phase change heat spreader 10 and the top phase change heat spreader 60 have an isothermal performance, increasing the heat dissipation area. Furthermore, the temperature difference within the same material layer inside the power device becomes smaller, reducing phenomena such as material fracture caused by uneven thermal stress distribution, decreasing the thermal resistance, improving the overall thermal performance of the power device, enhancing the service life and reliability of the power device, and enabling the power device to be applicable to high-temperature conditions. Therefore, the technical solution of this embodiment can effectively solve the problem that the packaging structure of power devices in related technologies is difficult to meet the heat dissipation requirements.

[0057] The main way of heat energy transfer inside the power device is heat conduction. Since the device is filled with heat-insulating gel inside, the heat generated by the chip can only pass through the solder layer, double-sided copper-clad ceramic substrate layer, bottom plate layer, etc. vertically by the chip, and finally the heat is conducted to the external environment through the heat dissipation device. Heat is transferred from the high-temperature side to the low-temperature side, and heat diffusion occurs during this process. When diffusion planes with different sizes and thermal conductivities come into contact, heat will undergo lateral diffusion, as Figure 1 shown. The heat diffusion angle is related to the thermal conductivity and size of the material. However, due to the small area of the silicon carbide chip, the effective heat transfer area actually participating in heat dissipation is only a small part below the chip. Therefore, due to the large heat generation of the chip and the limitation of the heat diffusion angle, the heat generated by the heat source 1 can only be transferred Figure 1 inside the two arrows on material one 2 and material two 3 in, resulting in a smaller heat dissipation area.

[0058] In this embodiment, the adopted bottom phase change heat spreader 10 and top phase change heat spreader 60 are different from the traditional material bottom plates with a single thermal conductivity. The bottom phase change heat spreader 10 and the top phase change heat spreader 60 can use the phase change principle to quickly balance the temperature distribution of the entire layer on the lower surface and the entire layer on the upper surface of the power chip 30, playing a role in expanding the heat dissipation area.

[0059] Compared with the silicon carbide power devices on the market, due to the better heat dissipation performance of the power device in this embodiment, more chips can be integrated inside the power device of this embodiment under the same external dimensions. Furthermore, the current and / or voltage rating of the power device is higher, and the power density is greater.

[0060] As Figures 4 to 7 shown, the bottom phase change heat spreader 10 includes a heat-conducting housing 11, the heat-conducting housing 11 has a vacuum chamber 12, a wick 15 is arranged on the inner side wall of the heat-conducting housing 11, and a phase change medium is filled in the vacuum chamber 12. After the power chip 30 releases heat, the liquid phase change medium near the power chip vaporizes, the gaseous phase change medium condenses into a liquid upon cooling, and the liquid phase change medium returns to the side near the power chip 30 under the action of the wick 15 and participates in the cycle again. Compared with the more widely used heat pipes, the bottom phase change heat spreader 10 has a very different internal heat conduction mode. The heat in the heat pipe is linearly conducted only in the front-back direction due to being restricted by the internal channel. However, the heat of the bottom phase change heat spreader 10 in this embodiment can be quickly conducted in multiple horizontal directions, making the temperature more uniform.

[0061] Specifically, the phase change medium is deionized water, ethanol or acetone. In specific design, it can be selected according to the required working temperature and the material of the heat-conducting housing 11. When in use, the phase change medium cannot cause physical changes to the heat-conducting housing 11 or chemical reactions with the heat-conducting housing 11. Preferably, deionized water is selected as the phase change medium, which has a high figure of merit under most working conditions and helps to improve the performance of the bottom phase change heat spreader 10.

[0062] As Figure 4 and Figure 5 shown, the heat-conducting housing 11 includes an evaporation half-shell 111 and a condensation half-shell 112, the wick 15 includes an evaporation wick layer 151 arranged on the evaporation half-shell 111 and a condensation wick layer 152 arranged on the condensation half-shell 112, the bottom substrate 20 is connected to the evaporation half-shell 111, and the bottom phase change heat spreader 10 further includes a liquid guide rib 13 connected between the evaporation wick layer 151 and the condensation wick layer 152. The wick 15 and the liquid guide rib 13 have a capillary structure. Both the wick 15 and the liquid guide rib 13 are capillary structures. The two ends of the liquid guide rib 13 are respectively connected to the evaporation wick layer 151 and the condensation wick layer 152. The liquid phase change medium can return to the side near the power chip 30 under the combined action of the wick 15 and the liquid guide rib 13 and participate in the cycle again.

[0063] As Figure 5 and Figure 6As shown, the bottom phase change heat spreader 10 further includes support columns 14 disposed within the vacuum chamber 12 and in abutting cooperation with both the evaporation half shell 111 and the condensation half shell 112. The support columns 14 are disposed within the vacuum chamber 12 and connected to the evaporation half shell 111 and the condensation half shell 112, which can enhance the structural stability and heat transfer capacity, prevent deformation of the bottom phase change heat spreader 10 during operation, resulting in phase change medium leakage or affecting the performance of the bottom phase change heat spreader 10. Their material is generally the same as that of the heat conduction housing 11. The liquid guiding ribs 13 include a first surrounding rib 131 disposed along the circumferential edge of the evaporation wick layer 151 and the condensation wick layer 152, and a second surrounding rib 132 disposed around the support columns 14. The liquid guiding ribs 13 are wrapped around the inner side of the peripheral wall surface and around the support columns 14 to promote the reflux of the phase change medium. Assembly holes for the support columns 14 are reserved during the production of the wick 15 to facilitate the installation and welding of the support.

[0064] The specific structure and working principle of the top phase change heat spreader 60 are the same as those of the bottom phase change heat spreader 10, and will not be elaborated here.

[0065] In this embodiment, the connection method between the various components inside the power device is achieved by soldering with a tin-gold solder sheet or sintering with nano silver paste to improve the temperature resistance performance of the power device. Specifically, the bottom phase change heat spreader 10 and the bottom substrate 20 are connected by soldering with a tin-gold solder sheet, and the top phase change heat spreader 60 and the top substrate 50 are also connected by soldering with a tin-gold solder sheet; the power chip 30 and the bottom substrate 20 are connected by sintering with nano silver paste. To enhance the solderability of the power chip 30, metal coatings such as titanium, nickel, or gold can be provided on the surface of the power chip; the heat conduction structure 40 is connected to the power chip 30 and the top substrate 50 by sintering with nano silver paste. The heat conduction structure 40 is specifically a metal heat conduction block, which can ensure the heat conduction performance of the heat conduction structure 40 on the one hand and achieve electrical connection between the upper surface of the power chip 30 and the corresponding position on the other hand (which will be described in detail later).

[0066] In this embodiment, both the bottom substrate 20 and the top substrate 50 are double-sided copper-clad ceramic plate structures. Among them, the copper layers on the sides of the bottom substrate 20 and the top substrate 50 facing the power chip 30 have specific shapes to achieve electrical connection inside the power device. Among them, the ceramic of the double-sided copper-clad ceramic plate uses alumina material with high thermal conductivity, and the copper layer surface is plated with nickel-palladium-gold to enhance solderability. The specific-shaped copper layers on the inner sides of the above-mentioned bottom substrate 20 and top substrate 50 can be achieved by etching.

[0067] Such as Figures 8 to 10 、 Figure 13 and Figure 14As shown, a first conductive layer 21 and a second conductive layer 22 are spaced apart on the bottom substrate 20, a third conductive layer 51 and a fourth conductive layer 52 are spaced apart on the top substrate 50, the power chip 30 includes an upper half-bridge switch chip 31 disposed on the first conductive layer 21 and a lower half-bridge switch chip 32 disposed on the second conductive layer 22, the heat conduction structure 40 includes a first metal heat conduction block 41 connected between the upper half-bridge switch chip 31 and the third conductive layer 51 and a second metal heat conduction block 42 connected between the lower half-bridge switch chip 32 and the fourth conductive layer 52, the power device further includes a third metal heat conduction block 71 connected between the second conductive layer 22 and the third conductive layer 51, the power device further includes an AC power terminal 81 connected to the second conductive layer 22, a first DC power terminal 82 connected to the first conductive layer 21, and a second DC power terminal 83 connected to the fourth conductive layer 52, the AC power terminal 81 is located between the first DC power terminal 82 and the second DC power terminal 83, and the AC power terminal 81, the first DC power terminal 82, and the second DC power terminal 83 extend in the same direction.

[0068] Specifically, the current path inside the power device is as follows:

[0069] When the upper half-bridge switch chip 31 is turned on, current enters from the first DC power terminal 82, flows to the first conductive layer 21, passes through the upper half-bridge switch chip 31 and the first metal heat conduction block 41 to enter the third conductive layer 51, then flows through the third metal heat conduction block 71 to the second conductive layer 22, and flows out via the AC power terminal 81;

[0070] When the lower half-bridge switch chip 32 is turned on, current enters from the AC power terminal 81, flows to the second conductive layer 22, passes through the lower half-bridge switch chip 32 and the second metal heat conduction block 42 to enter the fourth conductive layer 52, and then flows out via the second DC power terminal 83.

[0071] The ceramic layers of the bottom substrate 20 and the top substrate 50 can provide electrical insulation to isolate the high-voltage part inside the power device and the low-voltage parts such as the radiator outside the power device. The outer copper layer of the bottom substrate 20 is connected to the bottom phase change heat spreader 10 by welding, and the outer copper layer of the top substrate 50 is connected to the top phase change heat spreader 60 by welding to expand the heat dissipation area.

[0072] Among them, the AC power terminal 81, the first DC power terminal 82, and the second DC power terminal 83 extend in the same direction, which can reduce the inductance generated when current flows through the inside of the power device.

[0073] Such as Figure 9 , Figure 10 and Figure 17As shown, in this embodiment, the power device further includes an upper half-bridge diode chip 91 disposed on the first conductive layer 21 and connected in parallel with the upper half-bridge switch chip 31, and a lower half-bridge diode chip 92 disposed on the second conductive layer 22 and connected in parallel with the lower half-bridge switch chip 32. In the arrangement direction of the first conductive layer 21 and the second conductive layer 22, the upper half-bridge switch chip 31 is correspondingly disposed with the lower half-bridge diode chip 92, and the lower half-bridge switch chip 32 is correspondingly disposed with the upper half-bridge diode chip 91.

[0074] Among them, Figure 17 Fig. shows a commutation loop formed by the upper half-bridge switch chip 31 and the lower half-bridge diode chip 92. The AC power terminal 81, the first DC power terminal 82, and the second DC power terminal 83 control the inflow and outflow of the current of the entire power device. The current of the commutation loop of the power device flows through the first DC power terminal 82 (DC+ terminal), through the upper half-bridge switch chip 31, and then through the first metal heat sink 41, the third conductive layer 51, and the third metal heat sink 71, and flows to the lower half-bridge diode chip 92, and then flows out from the second DC power terminal 83 (DC- terminal) connected to the fourth conductive layer 52 through the fifth metal heat sink 102 disposed on the lower half-bridge diode chip 92. Compared with the chip layout of traditional power devices, the chip layout inside the power device in this embodiment is optimized, and the switch chip and the diode chip on the same commutation loop are disposed close to each other in layout, thereby shortening the path of the commutation loop of the power device, reducing the total area passed by the current during the flow of the current in the commutation loop, and reducing the stray inductance.

[0075] As Figures 10 to 12 shown, the power device further includes a fourth metal heat sink 101 connected between the upper half-bridge diode chip 91 and the third conductive layer 51, and a fifth metal heat sink 102 connected between the lower half-bridge diode chip 92 and the fourth conductive layer 52. The heat of the upper half-bridge diode chip 91 can be transferred upward through the fourth metal heat sink 101, and the heat of the lower half-bridge diode chip 92 can be transferred upward through the fifth metal heat sink 102. In addition, the fourth metal heat sink 101 and the fifth metal heat sink 102 can also realize the electrical connection between the upper half-bridge diode chip 91 and the lower half-bridge diode chip 92 and the corresponding structures.

[0076] Specifically, in this embodiment, the first metal heat sink 41, the second metal heat sink 42, the third metal heat sink 71, the fourth metal heat sink 101, and the fifth metal heat sink 102 are made of molybdenum-copper alloy, which realizes the electrical connection between the upper and lower half-bridges on the one hand and provides mechanical support for the power device on the other hand. Molybdenum-copper alloy is a composite material of molybdenum and copper, which combines the advantages of copper and molybdenum and has the advantages of good electrical conductivity, good thermal conductivity, and small thermal expansion.

[0077] AsFigure 9 , Figure 10 and Figure 12 As shown, a fifth conductive layer 23 and a sixth conductive layer 24 are also provided on the bottom substrate 20, and the power device further includes a gate terminal 84 connected to the fifth conductive layer 23 and an auxiliary source terminal 85 connected to the sixth conductive layer 24, the gate terminal 84 and the auxiliary source terminal 85 extend in a direction opposite to the extension direction of the AC power terminal 81, the fifth conductive layer 23 is conductively connected to the upper surface of the upper half-bridge switch chip 31 through the first conductive connector 201 (specifically, conductively connected to the gate 312 of the upper half-bridge switch chip 31), and the sixth conductive layer 24 is conductively connected to the upper surface of the upper half-bridge switch chip 31 through the second conductive connector 202 (specifically, conductively connected to the first source 311 of the upper half-bridge switch chip 31). Among them, the fifth conductive layer 23 and the sixth conductive layer 24 are located outside the first conductive layer 21, and the first conductive connector 201 and the second conductive connector 202 are both bonding wires (a type of aluminum wire).

[0078] Correspondingly, if Figure 9 , Figure 10 and Figure 11 As shown, the bottom substrate 20 is also provided with a seventh conductive layer 25 and an eighth conductive layer 26, the power device further includes a gate terminal 86 connected to the seventh conductive layer 25 and an auxiliary source terminal 87 connected to the eighth conductive layer 26, the gate terminal 86 and the auxiliary source terminal 87 extend in a direction opposite to the extension direction of the AC power terminal 81, the seventh conductive layer 25 is conductively connected to the upper surface of the lower half-bridge switch chip 32 through the third conductive connector 203 (specifically, conductively connected to the gate of the lower half-bridge switch chip 32), and the eighth conductive layer 26 is conductively connected to the upper surface of the lower half-bridge switch chip 32 through the fourth conductive connector 204 (specifically, conductively connected to the second source 321 of the lower half-bridge switch chip 32). Among them, the seventh conductive layer 25 and the eighth conductive layer 26 are located outside the second conductive layer 22, and the third conductive connector 203 and the fourth conductive connector 204 are both bonding wires (a type of aluminum wire).

[0079] like Figure 2 , Figure 3 , Figure 8 , Figure 9 and Figure 10As shown, the AC power terminal 81, the first DC power terminal 82, the second DC power terminal 83, the gate terminal 84, the auxiliary source terminal 85, the gate terminal 86, and the auxiliary source terminal 87 are all arranged in parallel with the bottom substrate 20 and the top substrate 50, such that the power device forms a flat structure. Compared with the power device in which the terminals are arranged perpendicular to the substrate, the overall volume of the power device in this embodiment is smaller. Moreover, the power terminals (specifically including: the AC power terminal 81, the first DC power terminal 82, and the second DC power terminal 83) and the signal terminals (specifically including: the gate terminal 84, the auxiliary source terminal 85, the gate terminal 86, and the auxiliary source terminal 87) extend in different directions respectively, facilitating processing and subsequent measurement.

[0080] Figure 15 and Figure 16 show a schematic structural diagram of the top surface and the bottom surface of the upper half-bridge switching chip 31. Among them, the top surface of the upper half-bridge switching chip 31 has a first source electrode 311 and a gate electrode 312 arranged at intervals, and the bottom surface of the upper half-bridge switching chip 31 has a drain electrode 313. The specific structure of the lower half-bridge switching chip 32 is similar to that of the upper half-bridge switching chip 31, and will not be elaborated here.

[0081] As Figure 10 and Figure 12 shown, the upper surface of the upper half-bridge switching chip 31 has a first source electrode 311. The first metal heat-conducting block 41 is located within the range of the first source electrode 311. A first avoidance recess 411 is provided on the first metal heat-conducting block 41 to expose a part of the first source electrode 311. The cross-section of the first metal heat-conducting block 41 forms an "L" shape, such that the first metal heat-conducting block 41 has a larger current-carrying and heat-conducting area, and at the same time enables a part of the first source electrode 311 to be exposed to conductively connect with the auxiliary source terminal 85.

[0082] As Figure 10 and Figure 11 shown, the upper surface of the lower half-bridge switching chip 32 has a second source electrode 321. The second metal heat-conducting block 42 is located within the range of the second source electrode 321. A second avoidance recess 421 is provided on the second metal heat-conducting block 42 to expose a part of the second source electrode 321. The cross-section of the second metal heat-conducting block 42 forms an "L" shape, such that the second metal heat-conducting block 42 has a larger current-carrying and heat-conducting area, and at the same time enables a part of the second source electrode 321 to be exposed to conductively connect with the auxiliary source terminal 87.

[0083] As Figure 2 and Figure 3As shown, the power device further includes a housing 300, which includes a top half-shell 301 disposed above the top-phase change heat spreader 60 and a bottom half-shell 302 disposed below the bottom-phase change heat spreader 10. Among them, an opening is provided on the top half-shell 301, and the top surface of the top-phase change heat spreader 60 is exposed through the opening for heat dissipation; an opening is provided on the bottom half-shell 302, and the bottom surface of the bottom-phase change heat spreader 10 is exposed through the opening for heat dissipation.

[0084] Among them, the housing 300 is made of polyphenylene sulfide resin (PPS), which has a high comparative tracking index, good insulation performance and high temperature resistance. The potting glue uses a high-temperature resistant epoxy resin, on the one hand, to isolate air from the internal structure of the power device; on the other hand, to increase the insulation performance inside the power device.

[0085] The power device includes, from top to bottom: a top half-shell 301, a top-phase change heat spreader 60, a solder layer (tin-gold solder sheet) between the top-phase change heat spreader 60 and the top substrate 50, a top substrate 50, a solder layer (nano-silver solder paste) between each metal heat conduction block and the top substrate 50, a metal heat conduction block made of molybdenum-copper alloy, a solder layer on the upper side of the chip (nano-silver solder paste), a silicon carbide chip (including a switching chip and a diode chip), a bonding wire, terminals (including power terminals and signal terminals), a solder layer on the lower side of the chip (nano-silver solder paste), a bottom substrate 20, a solder layer (tin-gold solder sheet) between the bottom substrate 20 and the bottom-phase change heat spreader 10, a bottom-phase change heat spreader 10 and a bottom half-shell 302.

[0086] Specifically, the connection methods between the various components of the power device in this embodiment are as follows:

[0087] The top substrate 50 is connected to the top-phase change heat spreader 60 through a tin-gold solder sheet welding process, and the bottom substrate 20 is connected to the bottom-phase change heat spreader 10 through a tin-gold solder sheet welding process;

[0088] The upper copper layer of the bottom substrate 20 is electrically connected to the bottom surfaces of the switching chip and the diode chip through silver sintering;

[0089] The upper copper layer of the bottom substrate 20 is electrically connected to different regions on the top surface of the switching chip through bonding wires;

[0090] The lower copper layer of the top substrate 50 is connected to the top surfaces of the switching chip and the diode chip through each metal heat conduction block;

[0091] The lower copper layer of the top substrate 50 and the upper copper layer of the bottom substrate 20 are electrically connected through a third metal heat conduction block 71;

[0092] The top phase change heat pipe 60 and the bottom phase change heat pipe 10 are hermetically connected to the top half shell 301 and the bottom half shell 302 by means of bonding or the like.

[0093] The packaging process flow of the power device in this embodiment is as follows:

[0094] Fabricate a metal mask, and deposit a metal coating such as titanium, nickel, or gold on the corresponding areas of the chips (including switch chips and diode chips);

[0095] Connect the metal heat conducting block to the coating area of the chip by using a silver sintering process;

[0096] Electrically connect the bottom of the chip to the upper copper layer of the bottom substrate 20 by using a silver sintering process;

[0097] Electrically connect the corresponding areas on the top of the chip to the upper copper layer of the bottom substrate 20 by using bonding wires;

[0098] Connect each electrode and terminal to the bottom substrate 20 or the top substrate 50 by using a silver sintering process;

[0099] Connect the top phase change heat pipe 60 to the upper copper layer of the top substrate 50 and connect the bottom phase change heat pipe 10 to the lower copper layer of the bottom substrate 20 by using a soldering process;

[0100] Connect the top half shell 301 and the top phase change heat pipe 60 and connect the bottom half shell 302 and the bottom phase change heat pipe 10 by using a frame bonding process;

[0101] Inject and degas potting glue into the power device.

[0102] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary explanation, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as limiting the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0103] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figure of the device. For example, if the device in the attached drawing is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations should be made for the spatial relative descriptions used here.

[0104] In addition, it should be noted that the use of terms such as "first", "second" etc. to define components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present utility model.

[0105] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A power device, characterized in that, Comprising: A bottom phase change heat spreader (10); A bottom substrate (20), connected to the upper surface of the bottom phase change heat spreader (10); A power chip (30), connected to the upper surface of the bottom substrate (20), and the heat of the power chip (30) can be transferred to the bottom phase change heat spreader (10) via the bottom substrate (20); A heat conduction structure (40), connected to the upper surface of the power chip (30); A top substrate (50), connected to the upper surface of the heat conduction structure (40); A top phase change heat spreader (60), connected to the upper surface of the top substrate (50), and the heat of the power chip (30) can be transferred to the top phase change heat spreader (60) via the heat conduction structure (40) and the top substrate (50).

2. The power device according to claim 1, characterized in that The bottom phase change heat spreader (10) includes a heat conduction shell (11), the heat conduction shell (11) has a vacuum chamber (12), a wick (15) is arranged on the inner side wall of the heat conduction shell (11), and a phase change medium is filled in the vacuum chamber (12).

3. The power device according to claim 2, characterized in that The heat conduction shell (11) includes an evaporation half shell (111) and a condensation half shell (112), the wick (15) includes an evaporation wick layer (151) arranged on the evaporation half shell (111) and a condensation wick layer (152) arranged on the condensation half shell (112), and the bottom substrate (20) is connected to the evaporation half shell (111), wherein, The bottom phase change heat spreader (10) further includes a liquid guiding rib (13) connected between the evaporation wick layer (151) and the condensation wick layer (152), and the wick (15) and the liquid guiding rib (13) have a capillary structure; and / or, The bottom phase change heat spreader (10) further includes a support column (14) arranged in the vacuum chamber (12) and in abutting fit with both the evaporation half shell (111) and the condensation half shell (112).

4. The power device according to claim 2 or 3, characterized in that, The phase change medium is deionized water, ethanol or acetone.

5. The power device according to any one of claims 1 to 3, wherein The bottom phase change heat spreader (10) and the bottom substrate (20) are connected by soldering with a tin solder sheet; and / or, The power chip (30) and the bottom substrate (20) are connected by sintering with a nano silver paste; and / or, The heat conduction structure (40) is connected to the power chip (30) and the top substrate (50) by sintering with a nano silver paste.

6. The power device according to any one of claims 1 to 3, characterized in that The bottom substrate (20) is provided with a first conductive layer (21) and a second conductive layer (22) at intervals. The top substrate (50) is provided with a third conductive layer (51) and a fourth conductive layer (52) at intervals. The power chip (30) includes an upper half-bridge switching chip (31) disposed on the first conductive layer (21) and a lower half-bridge switching chip (32) disposed on the second conductive layer (22). The heat conduction structure (40) includes a first metal heat conduction block (41) connected between the upper half-bridge switching chip (31) and the third conductive layer (51) and a second metal heat conduction block (42) connected between the lower half-bridge switching chip (32) and the fourth conductive layer (52). The power device further includes a third metal heat conduction block (71) connected between the second conductive layer (22) and the third conductive layer (51).

7. The power device according to claim 6, characterized in that The power device further includes an AC power terminal (81) connected to the second conductive layer (22), a first DC power terminal (82) connected to the first conductive layer (21), and a second DC power terminal (83) connected to the fourth conductive layer (52). The AC power terminal (81) is located between the first DC power terminal (82) and the second DC power terminal (83). The AC power terminal (81), the first DC power terminal (82), and the second DC power terminal (83) extend in the same direction.

8. The power device according to claim 6, characterized in that, The power device further includes an upper half-bridge diode chip (91) disposed on the first conductive layer (21) and connected in parallel with the upper half-bridge switching chip (31), and a lower half-bridge diode chip (92) disposed on the second conductive layer (22) and connected in parallel with the lower half-bridge switching chip (32). In the arrangement direction of the first conductive layer (21) and the second conductive layer (22), the upper half-bridge switching chip (31) is disposed corresponding to the lower half-bridge diode chip (92), and the lower half-bridge switching chip (32) is disposed corresponding to the upper half-bridge diode chip (91).

9. The power device according to claim 8, wherein The power device further includes a fourth metal heat conduction block (101) connected between the upper half-bridge diode chip (91) and the third conductive layer (51) and a fifth metal heat conduction block (102) connected between the lower half-bridge diode chip (92) and the fourth conductive layer (52).

10. The power device according to claim 6, wherein The upper surface of the upper half-bridge switching chip (31) has a first source electrode (311). The first metal heat conduction block (41) is located within the range of the first source electrode (311). The first metal heat conduction block (41) is provided with a first avoidance recess (411) to expose a part of the first source electrode (311); and / or, The upper surface of the lower half-bridge switching chip (32) has a second source electrode (321), the second metal heat conducting block (42) is located within the range of the second source electrode (321), and a second avoidance recess (421) is provided on the second metal heat conducting block (42) to expose a part of the second source electrode (321).

11. The power device according to claim 7, characterized in that, A fifth conductive layer (23) and a sixth conductive layer (24) are further provided on the bottom substrate (20). The power device further includes a gate terminal (84) connected to the fifth conductive layer (23) and an auxiliary source terminal (85) connected to the sixth conductive layer (24). The gate terminal (84) and the auxiliary source terminal (85) extend in a direction opposite to the extension direction of the AC power terminal (81). The fifth conductive layer (23) is conductively connected to the upper surface of the upper half-bridge switching chip (31) through a first conductive connection member (201), and the sixth conductive layer (24) is conductively connected to the upper surface of the upper half-bridge switching chip (31) through a second conductive connection member (202).

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