Power semiconductor device and power module

Abstract

The invention relates to the field of new energy power generation, and discloses a power semiconductor device and a power module, and the device comprises a substrate, a heat dissipation structure, and a power chip. The heat dissipation structure is arranged on the upper surface of the substrate and connected with the substrate, and the power chip is arranged on the upper surface of the heat dissipation structure and connected with the heat dissipation structure; the heat dissipation structure comprises a sealed frame and liquid metal, the frame is provided with a cavity, and the cavity is filled with the liquid metal. The heat dissipation structure is arranged in the power semiconductor device, the heat dissipation structure comprises the liquid metal, the liquid metal can absorb heat in the melting process while the temperature is kept unchanged, and the heat capacity is equivalent to infinity, so that the overall heat capacity of the power semiconductor device is greatly increased, and the heat time constant is increased; therefore, the heating rate of the power chip can be suppressed when the power is overloaded, and the overload capacity of the module is improved. Compared with a conventional phase change material, the heat conductivity coefficient of the liquid metal is large, the phase change melting rate can be increased, and meanwhile the influence on the steady-state thermal resistance of the power chip is small.

Description

Technical Field

[0001] The present application relates to the field of renewable energy power generation, and in particular to a power semiconductor device and a power module. Background Art

[0002] Flexible DC transmission is a new transmission technology that uses a voltage source converter and DC capacitors to achieve voltage support. Flexible DC transmission technology can provide support for new energy power generation systems. An important issue it faces is that the flexible DC transmission converter needs to have a certain short-term overload capacity. As the core of the power converter, power semiconductor devices currently have a relatively weak short-term overload capacity.

[0003] Therefore, how to solve the above technical problems should be the focus of technical personnel in this field. Summary of the invention

[0004] The purpose of the present application is to provide a power semiconductor device and a power module to improve the short-term overload capability of the power semiconductor device.

[0005] In order to solve the above technical problems, the present application provides a power semiconductor device, comprising: a substrate, a heat dissipation structure and a power chip;

[0006] The heat dissipation structure is arranged on the upper surface of the substrate and connected to the substrate, and the power chip is arranged on the upper surface of the heat dissipation structure and connected to the heat dissipation structure;

[0007] The heat dissipation structure comprises a sealed frame and liquid metal, wherein the frame has a cavity, and the liquid metal is filled in the cavity.

[0008] Optionally, the frame comprises a cover plate and a frame body having a plurality of recesses;

[0009] The opening of the recess is located on the upper surface of the frame body; the cover plate is connected to the upper surface of the frame body and forms the cavity with the recess;

[0010] The cover plate includes a heat sink.

[0011] Optionally, the ratio of the sum of the opening areas of the plurality of recesses to the area of ​​the upper surface of the frame body is S, wherein S satisfies 50%≤S≤95%; and / or,

[0012] The depth of the recess is h1, and the height of the frame body is h2, wherein h1 and h2 satisfy: 50%≤h1 / h2≤95%; and / or,

[0013] Along the thickness direction of the frame, the width of the opening cross section of the recess is D, wherein D satisfies: 1 mm ≤ D ≤ 10 mm.

[0014] Optionally, the recess comprises a recessed hole and / or a groove.

[0015] Optionally, along the opening of the concave hole to the bottom of the concave hole, the apertures of the concave hole are all equal; and / or,

[0016] The aperture of the concave hole gradually decreases from the opening of the concave hole to the bottom of the concave hole; and / or,

[0017] The diameter of the concave hole gradually decreases from the center to the edges of the frame body; and / or,

[0018] Along the length direction of the frame body, the frame includes a first area, a second area and a third area connected in sequence, wherein the opening ratio of the second area is not less than the opening ratio of the first area or the third area.

[0019] Optionally, the substrate comprises a metal substrate and a DBC substrate arranged in a stacked manner;

[0020] The DBC substrate is located on a side of the metal substrate close to the heat dissipation structure; the DBC substrate includes a first heat-conducting layer, a ceramic layer and a second heat-conducting layer stacked in sequence.

[0021] Optionally, the ceramic layer comprises AlN, and the heat dissipation structure is connected to the substrate by nanosilver sintering; and / or,

[0022] The ceramic layer includes Al2O3, and the heat dissipation structure is connected to the substrate by welding.

[0023] Optionally, it also includes:

[0024] An insulating gel layer is located on the upper surface of the power chip.

[0025] The present application also provides a power module, comprising any of the above-mentioned power semiconductor devices and a heat sink.

[0026] Optionally, the radiator contains a cooling medium;

[0027] A plurality of spoiler columns are disposed on a surface of the substrate away from the heat dissipation structure, and the spoiler columns extend into the heat sink.

[0028] A power semiconductor device provided in the present application includes: a substrate, a heat dissipation structure and a power chip; the heat dissipation structure is arranged on the upper surface of the substrate and connected to the substrate, and the power chip is arranged on the upper surface of the heat dissipation structure and connected to the heat dissipation structure; the heat dissipation structure includes a sealed frame and liquid metal, the frame has a cavity, and the liquid metal is filled in the cavity.

[0029] It can be seen that in the power semiconductor device of the present application, a heat dissipation structure is provided between the substrate and the power chip, and the heat dissipation structure includes liquid metal, which can absorb heat during the melting process while keeping the temperature constant, and the heat capacity is equivalent to infinity, so that the overall heat capacity of the power semiconductor device is greatly increased, and the thermal time constant is increased, so that the heating rate of the power chip can be suppressed when the power is overloaded, and the overload capacity of the module can be improved. In addition, compared with conventional phase change materials, the thermal conductivity of liquid metal is relatively large, which can increase the phase change melting rate, and at the same time has little effect on the steady-state thermal resistance of the power chip.

[0030] In addition, the present application also provides a power module having the above advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the structure of a power semiconductor device provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of a heat dissipation structure provided in an embodiment of the present application Figure 1 ;

[0034] Figure 3 A schematic diagram of heat transfer along the thickness direction of a vacuum vapor chamber provided in an embodiment of the present application;

[0035] Figure 4 A schematic diagram of heat transfer along the length direction of a vacuum vapor chamber provided in an embodiment of the present application;

[0036] Figure 5 A schematic cross-sectional view of a frame body provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of a heat dissipation structure provided in an embodiment of the present application Figure 2 ;

[0038] Figure 7 A schematic diagram of a heat dissipation structure provided in an embodiment of the present application Figure 3 ;

[0039] Figure 8 A schematic diagram of the structure of a DBC substrate provided in an embodiment of the present application;

[0040] Fig. 9 A schematic diagram of the bottom of a power semiconductor device provided in an embodiment of the present application;

[0041] Fig.10 It is a curve diagram showing the maximum temperature of IGBT power chips in different power semiconductor devices changing with time;

[0042] In the figure, 1. substrate, 2. heat dissipation structure, 3. power chip, 4. spoiler column, 11. metal substrate, 12. DBC substrate, 121. first thermal conductive layer, 122. ceramic layer, 123. second thermal conductive layer, 21. frame, 22. liquid metal, 211. cover plate, 2121. recess, 212. frame body, 2111. shell, 2112. wick, 01. vacuum chamber. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] The current power semiconductor devices include power chips and substrates. The power chips are directly fixed on the substrates, and the short-term overload capacity of power semiconductor devices is relatively weak. The reasons include: first, the thermal capacity of the power chip is relatively low. Under the impact of power overload, the time for the power chip to reach the over-temperature threshold is usually in the millisecond level, which makes it impossible to meet the strong overload requirements of the grid-type converter; second, the heat generation of the power chip is relatively concentrated, resulting in poor temperature uniformity of the substrate of the power semiconductor device, and the temperature difference between the area below the power chip and the edge area is large.

[0046] In view of this, the present application provides a power semiconductor device, please refer to Figure 1 to Figure 2 , which may include:

[0047] Substrate 1, heat dissipation structure 2 and power chip 3;

[0048] The heat dissipation structure 2 is disposed on the upper surface of the substrate 1 and connected to the substrate 1, and the power chip 3 is disposed on the upper surface of the heat dissipation structure 2 and connected to the heat dissipation structure 2;

[0049] The heat dissipation structure 2 includes a sealed frame 21 and liquid metal 22 . The frame 21 has a cavity, and the liquid metal 22 is filled in the cavity.

[0050] In the present application, the Z direction is the thickness direction of the power semiconductor device, the X direction is the length direction of the power semiconductor device, and the Y direction is the width direction of the power semiconductor device. The positive Z direction is the upward direction described in the present application, and the negative Z direction is the downward direction.

[0051] It should be noted that the power semiconductor device may further include a housing covering the power chip to meet dustproof and insulation requirements, and terminals are led out from the inside of the power semiconductor device.

[0052] It should be pointed out that in this embodiment, the number and type of the power chips 3 are not limited and depend on the circumstances.

[0053] The power chips 3 are electrically connected to each other through wire bonding.

[0054] As an implementation method, the power chip 3 may include an IGBT (Insulated Gate Bipolar Transistor) power chip and a diode power chip.

[0055] Liquid metal 22 refers to a metal material that is liquid at room temperature or near a higher temperature, and has many advantages such as high thermal conductivity, a wide adjustable solid-liquid phase transition temperature range, and a small volume change rate before and after solid-liquid conversion.

[0056] The phase change temperature of the liquid metal 22 is lower than the maximum operating temperature of the power chip 3 .

[0057] It should be noted that, in this embodiment, there is no specific limitation on the type of liquid metal 22 and it can be selected by the user.

[0058] Exemplarily, the liquid metal 22 may be liquid gallium, liquid gallium alloy, liquid bismuth-based alloy, etc., wherein the liquid gallium alloy includes but is not limited to gallium-indium alloy or gallium-indium-tin alloy, and the bismuth-based alloy includes but is not limited to bismuth-indium-tin alloy.

[0059] The frame 21 is sealed, and can confine the liquid metal 22 in the cavity after the liquid metal 22 absorbs heat and melts, to prevent it from flowing freely and causing a short circuit.

[0060] In this embodiment, the structure of the frame 21 is not limited, and it only needs to have a cavity inside and be sealed.

[0061] The connection method between the heat dissipation structure 2 and the substrate 1 is not limited in this embodiment, as long as the heat dissipation structure 2 and the substrate 1 can be connected.

[0062] As an implementable embodiment, in order to improve the connection stability between the heat dissipation structure 2 and the substrate 1, the heat dissipation structure 2 and the substrate 1 can be connected by welding.

[0063] It should be noted that the present application does not limit the solder between the heat dissipation structure 2 and the substrate 1. For example, the solder for the welding connection includes tin-based solder and the like.

[0064] As another possible implementation method, the heat dissipation structure 2 and the substrate 1 are connected by nano-silver sintering; this can not only improve the connection stability between the heat dissipation structure 2 and the substrate 1, but also further improve the heat transfer performance of the power module.

[0065] The connection method between the power chip 3 and the heat dissipation structure 2 is not limited in this embodiment, as long as the heat dissipation structure 2 and the power chip 3 can be connected.

[0066] As an implementable embodiment, the power chip 3 and the heat dissipation structure 2 may be connected by welding to improve the connection stability between the power chip 3 and the heat dissipation structure 2 .

[0067] It should be noted that the present application does not limit the solder between the power chip 3 and the heat dissipation structure 2. For example, the solder for the welding connection includes tin-based solder and the like.

[0068] As another possible implementation method, the power chip 3 and the heat dissipation structure 2 are connected by nano-silver sintering to improve the connection stability between the power chip 3 and the heat dissipation structure 2 and improve the heat transfer performance of the power module.

[0069] In the power semiconductor device of this embodiment, a heat dissipation structure 2 is provided between the substrate 1 and the power chip 3. The heat dissipation structure 2 includes liquid metal 22. The liquid metal 22 can absorb heat during the melting process while the temperature remains unchanged. The heat capacity is equivalent to infinity, which greatly increases the overall heat capacity of the power semiconductor device and the thermal time constant. Therefore, the heating rate of the power chip 3 can be suppressed when the power is overloaded, and the overload capacity of the module can be improved. In addition, compared with conventional phase change materials, the thermal conductivity of the liquid metal 22 is relatively large, which can increase the phase change melting rate, and at the same time, it has little effect on the steady-state thermal resistance of the power chip 3.

[0070] Based on the above embodiments, in one embodiment of the present application, please refer to Figure 2 , the frame 21 includes a cover plate 211 and a frame body 212 having a plurality of recesses 2121;

[0071] The opening of the recess 2121 is located on the upper surface of the frame body 212 ; the cover plate 211 is connected to the upper surface of the frame body 212 and forms the cavity with the recess 2121 ; the cover plate 211 includes a heat sink.

[0072] When manufacturing the heat dissipation structure 2 , the liquid metal 22 is first filled into the recess 2121 of the frame body 212 , and then the cover plate 211 is fixedly connected to the frame body 212 .

[0073] The material of the frame body 212 may be a metal material, such as copper, which has good thermal conductivity and can quickly conduct heat to the liquid metal 22 .

[0074] It should be noted that the connection method between the cover plate 211 and the frame body 212 is not limited in this embodiment.

[0075] As an implementation method, in order to improve the connection stability between the cover plate 211 and the frame body 212, the cover plate 211 and the frame body 212 may be connected by welding. The welding material of the welding connection may be tin-based solder.

[0076] As another possible implementation, the cover plate 211 and the frame body 212 may be connected by nano-silver sintering, which can improve the connection stability between the cover plate 211 and the frame body 212 and also improve the heat transfer performance of the power semiconductor device.

[0077] In this embodiment, the number of the recesses 2121 is not limited and can be set at will. The recesses 2121 can be arranged in a regular array on the frame body 212, or can be arranged in an irregular manner, both of which are within the protection scope of this application.

[0078] The recess 2121 is formed by the upper surface of the frame body 212 being recessed toward the lower surface of the frame body 212. When the cover plate 211 covers the upper surface of the frame body 212 and is connected to the upper surface of the frame body 212, the opening of the recess 2121 is covered, thereby forming a sealed cavity.

[0079] It should be noted that in this embodiment, there is no limitation on the type of the cover plate 211 , as long as it can achieve heat conduction, and the type can be selected at will.

[0080] In one embodiment of the present application, the cover plate 211 may be a vacuum chamber (VC) heat spreader.

[0081] The functions of the vacuum chamber heat sink include: first, it can improve the temperature uniformity of the power semiconductor device in the planar direction; second, it can improve the consistency of the melt volume fraction of the liquid metal 22 and increase the utilization rate of the liquid metal 22; third, it can reduce the steady-state thermal resistance of the power module and reduce the initial power chip 3 temperature at the moment of power overload.

[0082] As an implementation method, Figure 3 to Figure 4 As shown, the vacuum chamber heat spreader includes a shell 2111 and a liquid wick 2112, the shell 2111 has a vacuum chamber 01, and a phase change medium is injected into the vacuum chamber 01; the liquid wick 2112 is located on the inner wall of the vacuum chamber 01 close to the condensation end of the vacuum chamber heat spreader, and on the inner wall close to the evaporation end of the vacuum chamber heat spreader, the liquid wick has a capillary structure, and the capillary force is used to enable the phase change medium to achieve two-dimensional diffusion flow inside the liquid wick.

[0083] The shell 2111 is evacuated before sealing to ensure a good vacuum degree.

[0084] The phase change working fluid is a refrigerant, such as water, ammonia, R134a, methanol, acetone, etc.

[0085] The working fluid is adsorbed in the liquid absorption core 2112, and the working fluid absorbs the heat from the heat source and evaporates at the evaporation end; the steam flows to the condensation end under the action of the pressure difference; the steam dissipates heat and condenses at the condensation end; the liquid at the condensation end returns to the evaporation end under the action of capillary pressure to carry out the working cycle.

[0086] The thickness of the vacuum chamber heat spreader can range from 3.2 mm to 3.5 mm, the height of the vacuum chamber 01 can range from 1.4 mm to 1.6 mm, the ratio of the upper surface area of ​​the vacuum chamber 01 to the upper surface area of ​​the vacuum chamber heat spreader can range from 80% to 85%, and the equivalent thermal conductivity of the vacuum chamber 01 and the wick 2112 can range from 5000 to 20000 W / (mK).

[0087] In order to improve the stability of the heat sink in the vacuum chamber, a support column 2113 may be further provided in the shell 2111 .

[0088] Based on any of the above embodiments, in one embodiment of the present application, the ratio of the sum of the opening areas of the plurality of recesses 2121 to the area of ​​the upper surface of the frame body 212 may be S, where S satisfies 50%≤S≤95%.

[0089] The sum of the opening areas of the plurality of recesses 2121 is the sum of the opening areas of all the recesses 2121 .

[0090] The ratio of the sum of the opening areas of the multiple recesses 2121 to the area of ​​the upper surface of the frame body 212 is related to the amount of liquid metal 22 in the heat dissipation structure 2. If the ratio is too small, the amount of liquid metal 22 is small and the heat transfer effect is relatively poor. If the ratio is too large, the amount of liquid metal 22 is too much, which affects the steady-state thermal resistance of the IGBT power chip and the heat transfer effect becomes worse.

[0091] Exemplarily, the ratio of the opening area of ​​the recess 2121 to the area of ​​the upper surface of the frame body 212 can be 50%, 60%, 70%, 75%, 77%, 79%, 80%, 90%, 95%, etc.

[0092] Based on any of the above embodiments, in one embodiment of the present application, Figure 5 As shown, the depth of the recess 2121 is h1, and the height of the frame body 212 is h2, wherein h1 and h2 satisfy: 50%≤h1 / h2≤95%.

[0093] The ratio of the depth h1 of the recess 2121 to the height h2 of the frame body 212 is related to the thickness between the bottom of the recess 2121 and the lower surface of the frame body 212, thereby affecting the heat transfer between the frame body 212 and the liquid metal 22. Setting the ratio between 50% and 95% can ensure heat resistance, so that the heat transfer effect between the liquid metal 22 and the copper frame 21 is relatively good, thereby further suppressing the temperature rise rate of the power chip 3 when the power is overloaded.

[0094] Exemplarily, the ratio of the depth h1 of the recess 2121 to the height h2 of the frame body 212 may be 50%, 60%, 70%, 85%, 86%, 88%, 90%, 95%, etc.

[0095] Based on any of the above embodiments, in one embodiment of the present application, Figure 5 As shown, along the thickness direction of the frame 21 , the width of the opening cross section of the recess 2121 is D, wherein D satisfies: 1 mm ≤ D ≤ 10 mm.

[0096] The opening cross-sectional width D of the recess 2121 is related to the amount of liquid metal 22 in the heat dissipation structure 2. If the opening cross-sectional width D of the recess 2121 is too small, the amount of liquid metal 22 is too small, resulting in poor transient effect of the power chip 3. If the opening cross-sectional width D of the recess 2121 is too large, the amount of liquid metal 22 is too large, affecting the steady-state temperature rise.

[0097] Illustratively, the opening cross-sectional width D of the recess 2121 may be 1 mm, 2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 3 mm, 5 mm, 7 mm, 9 mm, 10 mm, etc.

[0098] It should be noted that the width of the opening cross section of the recessed portion 2121 may be a cross section in any direction such as the length direction or the width direction.

[0099] The width of the opening cross section of the recess 2121 is preferably parallel to the length direction of the power semiconductor device shown in the drawings, so as to achieve better transient effect and steady-state temperature rise of the power chip 3.

[0100] Based on any of the above embodiments, in one embodiment of the present application, the concave portion 2121 includes a concave hole and / or a groove, wherein the groove is in the shape of a long strip; the cross-sectional shape of the concave hole includes but is not limited to a circle, a rectangle, a square, an ellipse, and a hexagon.

[0101] The concave portion 2121 is arranged as a concave hole and / or a groove, so as to increase the equivalent thermal conductivity of the liquid metal 22 in a direction perpendicular to the power chip 3 (thickness direction).

[0102] like Figure 2 As shown, as an implementation method, the apertures of the recessed holes are equal at all locations along the opening of the recessed holes to the bottom of the recessed holes, which can improve the equivalent thermal conductivity of the heat dissipation structure 2 in the vertical direction and reduce the influence of the liquid metal 22 on the steady-state thermal resistance of the power chip 3.

[0103] The direction from the opening of the concave hole to the bottom of the concave hole is along the thickness direction of the frame 21 .

[0104] like Figure 6 As shown, as an implementation method, the aperture of the concave hole gradually decreases from the opening of the concave hole to the bottom of the concave hole, which can further improve the utilization rate of the liquid metal 22 during the transient overload process.

[0105] like Figure 7 As shown, as an implementation method, the aperture of the concave hole gradually decreases from the center of the frame body 212 to the edges thereof, which can further improve the utilization rate of the liquid metal 22 during transient overload.

[0106] As an implementation method, along the length direction of the frame body, the frame includes a first zone, a second zone and a third zone connected in sequence, wherein the opening ratio of the second zone is not less than the opening ratio of the first zone or the third zone.

[0107] The opening ratio refers to the percentage of the sum of the opening areas of all recesses 2121 in each region to the area of ​​the region.

[0108] The second zone is located between the first zone and the third zone, and the opening ratio of the second zone is not less than the opening ratio of the first zone or the third zone, which can further improve the utilization rate of the liquid metal 22 during the transient overload process.

[0109] It should be noted that the lengths of the first zone, the second zone, and the third zone are not limited in this embodiment. For example, the first zone, the second zone, and the third zone may be arranged equidistantly, that is, the lengths of the zones are equal, or the first zone, the second zone, and the third zone may be arranged at other lengths according to the situation.

[0110] Based on any of the above embodiments, in one embodiment of the present application, the power semiconductor device may further include:

[0111] An insulating gel layer is located on the upper surface of the power chip 3 .

[0112] The insulating gel layer can play the role of insulation and dust prevention, and extend the service life of the power device.

[0113] Based on any of the above embodiments, in one embodiment of the present application, Figure 1 As shown, the base 1 includes a metal substrate 11 and a DBC substrate 12 which are stacked; the DBC substrate 12 is located on a side of the metal substrate 11 close to the heat dissipation structure 2; the DBC substrate 12 includes a first heat-conducting layer 121, a ceramic layer 122 and a second heat-conducting layer 123 which are stacked in sequence.

[0114] The material of the metal substrate 11 includes but is not limited to copper, iron, aluminum or other metals or alloys. The material of the metal substrate 11 is preferably copper to improve the heat dissipation effect of the base 1.

[0115] The connection between the DBC substrate 12 (direct bonded copper, directly copper-clad ceramic substrate) and the metal substrate 11 can be a welding connection to improve the firmness of the connection between the DBC substrate 12 and the metal substrate 11. Alternatively, the DBC substrate 12 and the metal substrate 11 are connected by nanosilver sintering to further improve the heat transfer performance of the power module.

[0116] Please refer to Figure 8 The DBC substrate 12 includes a stacked first heat-conducting layer 121 , a ceramic layer 122 , and a second heat-conducting layer 123 . The main function of the ceramic layer 122 is to ensure the insulation withstand voltage level between the power chip 3 and the metal substrate 11 .

[0117] The materials of the first heat-conducting layer 121 and the second heat-conducting layer 123 include but are not limited to copper, iron, aluminum or other metals or alloys. The materials of the first heat-conducting layer 121 and the second heat-conducting layer 123 are preferably copper to improve the heat dissipation effect of the DBC substrate 12 .

[0118] In this embodiment, there is no limitation on the type of the ceramic layer, and the type can be selected at will.

[0119] As an implementation method, the ceramic layer 122 in the DBC substrate 12 may be an Al2O3 ceramic layer, and the heat dissipation structure is connected to the substrate by welding.

[0120] As another possible implementation, the ceramic layer 122 in the DBC substrate 12 may be an AlN ceramic layer, and the heat dissipation structure and the substrate are connected by nano-silver sintering to further improve the steady-state thermal performance of the power module.

[0121] The following simulation is performed on the maximum temperature change of the IGBT power chip in the power semiconductor device of the present application over time. First, the IGBT power chip reaches a steady state under the condition of 1118W heat loss, and then the power consumption is changed to 3354W for 10s. The copper substrate temperature is set to the fixed temperature boundary of 85℃, and the temperature boundary during overload is set to increase linearly from 85℃ to 90℃.

[0122] The simulation experiments include 5, namely: 1. Power semiconductor devices in the prior art; 2. The power semiconductor device has a heat dissipation structure, and the heat dissipation structure is filled with liquid metal with a melting point of 118°C; 3. The power semiconductor device has a heat dissipation structure, and the heat dissipation structure is filled with liquid metal with a melting point of 118°C, the cover plate is a VC heat spreader, and the thermal conductivity of the VC heat spreader is 5000 W / (mK); 4. The power semiconductor device has a heat dissipation structure, and the heat dissipation structure is filled with liquid metal with a melting point of 118°C, the cover plate is a VC heat spreader, and the thermal conductivity of the VC heat spreader is 20000 W / (mK); 5. The power semiconductor device has a heat dissipation structure, and the heat dissipation structure is filled with liquid metal, the cover plate is a VC heat spreader, and the thermal conductivity of the VC heat spreader is 20000 W / (mK), the melting point of the liquid metal is 106°C, and the density is 7000kg / m 3 , thermal conductivity 60W / (mK), specific heat capacity 500J / (gK), latent heat 56J / g.

[0123] The maximum temperature of the IGBT power chip in the above different power semiconductor devices varies with time. Fig.10 As shown, the horizontal axis is time and the vertical axis is temperature. The maximum temperature variation curves of the IGBT power chip in the five different power semiconductor devices 1 to 5 are respectively Fig.10 For curves A, B, C, D, and E in FIG, the maximum allowable temperature of the IGBT power chip is 175°C (dashed line).

[0124] In the prior art power semiconductor device, the overheating time of the IGBT power chip is within 0.1s (curve A). When only liquid metal is filled (curve B), the initial overload temperature and the termination temperature of the IGBT power chip are greater than those of the prior art power semiconductor device (increased steady-state thermal resistance), but the temperature rise rate of the power chip is suppressed (increased transient heat capacity), so that the time to reach the threshold temperature is increased to about 0.3s. After adding the VC heat spreader and the liquid metal structure at the same time (curve C), the steady-state temperature and the temperature rise rate of the IGBT power chip are reduced at the same time. By increasing the equivalent thermal conductivity of the VC heat spreader, the power chip can be kept below its maximum allowable temperature at the end of the overload. Finally, by comparing curves D and E, it can be seen that the melting point of the liquid metal phase change material mainly affects the temperature of the IGBT power chip at the initial overload stage, and appropriately reducing the melting point can reduce the initial overload temperature of the power chip.

[0125] Depend on Fig.10 It can be seen that the present application adds a heat dissipation structure to the power semiconductor device, which improves the thermal performance in two main aspects: first, the steady-state thermal resistance is reduced, and the initial overload temperature (steady-state temperature, the temperature when time is 0) is reduced from 126°C to about 111°C; second, the transient heat capacity is increased, and the time from the initial temperature increase to the linear growth zone is increased from 0.3s to about 4s, which significantly suppresses the temperature rise rate of the IGBT power chip during the overload process.

[0126] The present application also provides a power module, comprising the power semiconductor device and the heat sink described in any one of the above embodiments.

[0127] The power module may also include capacitors, heat sinks, copper busbars, etc.

[0128] Please refer to Fig. 9 , based on any of the above embodiments, in one embodiment of the present application, the radiator has a cooling medium;

[0129] A plurality of spoiler columns 4 are disposed on a surface of the substrate 1 away from the heat dissipation structure 2 , and the spoiler columns 4 extend into the heat sink.

[0130] The radiator may be a liquid-cooled radiator, and the spoiler column 4 may be directly embedded in the cooling medium inside the radiator, eliminating the thermal resistance of the thermal conductive silicone grease between the power semiconductor device and the radiator, thereby optimizing its heat transfer performance.

[0131] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0132] The power semiconductor device and power module provided by the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the scheme and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A power semiconductor device, characterized in that: include: Substrate, heat dissipation structure and power chip; The heat dissipation structure is arranged on the upper surface of the substrate and connected to the substrate, and the power chip is arranged on the upper surface of the heat dissipation structure and connected to the heat dissipation structure; The heat dissipation structure comprises a sealed frame and liquid metal, wherein the frame has a cavity, and the liquid metal is filled in the cavity.

2. The power semiconductor device according to claim 1, characterized in that: The frame includes a cover plate and a frame body having a plurality of recesses; The opening of the recess is located on the upper surface of the frame body; the cover plate is connected to the upper surface of the frame body and forms the cavity with the recess; The cover plate includes a heat sink.

3. The power semiconductor device according to claim 2, characterized in that: The ratio of the sum of the opening areas of the plurality of recesses to the area of ​​the upper surface of the frame body is S, wherein S satisfies 50%≤S≤95%; and / or, The depth of the recess is h1, and the height of the frame body is h2, wherein h1 and h2 satisfy: 50%≤h1 / h2≤95%; and / or, Along the thickness direction of the frame, the width of the opening cross section of the recess is D, wherein D satisfies: 1 mm ≤ D ≤ 10 mm.

4. The power semiconductor device according to claim 2, characterized in that: The recessed portion includes a recessed hole and / or a groove.

5. The power semiconductor device according to claim 4, characterized in that: The apertures of the concave hole are equal at all locations along the opening of the concave hole to the bottom of the concave hole; and / or, The aperture of the concave hole gradually decreases from the opening of the concave hole to the bottom of the concave hole; and / or, The diameter of the concave hole gradually decreases from the center to the edges of the frame body; and / or, Along the length direction of the frame body, the frame includes a first area, a second area and a third area connected in sequence, wherein the opening ratio of the second area is not less than the opening ratio of the first area or the third area.

6. The power semiconductor device according to claim 1, characterized in that: The substrate comprises a metal substrate and a DBC substrate which are stacked; The DBC substrate is located on a side of the metal substrate close to the heat dissipation structure; the DBC substrate includes a first heat-conducting layer, a ceramic layer and a second heat-conducting layer stacked in sequence.

7. The power semiconductor device according to claim 6, characterized in that: The ceramic layer comprises AlN, and the heat dissipation structure is connected to the substrate by nano-silver sintering; and / or, The ceramic layer includes Al2O3, and the heat dissipation structure is connected to the substrate by welding.

8. The power semiconductor device according to any one of claims 1 to 7, characterized in that: Also includes: An insulating gel layer is located on the upper surface of the power chip.

9. A power module, characterized in that: The invention comprises a power semiconductor device as claimed in any one of claims 1 to 8 and a heat sink.

10. The power module according to claim 9, characterized in that: The radiator contains a cooling medium; A plurality of spoiler columns are disposed on a surface of the substrate away from the heat dissipation structure, and the spoiler columns extend into the heat sink.

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