Single-double-face composite heat dissipation structure of double-face packaging silicon carbide power module

Abstract

The invention discloses a single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module. The single-double-face composite heat dissipation structure comprises a metal plate, a double-face packaged silicon carbide power module and a radiator which are sequentially arranged from top to bottom, the metal plate and the radiator are connected with a top substrate and a bottom substrate of the double-face packaged silicon carbide power module respectively, and the two sides of the bottom face of the metal plate are connected with the top face of the radiator. According to the single-double-face composite heat dissipation structure, the heat dissipation efficiency of the double-face packaging silicon carbide power module is guaranteed, meanwhile, the efficient and light-weight design of the module and a heat dissipation system is achieved, and the power loss of the heat dissipation system can be effectively reduced; through the mutual constraint effect between the structures, the thermal stress of the module can be improved, and the working reliability of the power module is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module. Background Art

[0002] Silicon carbide (SiC) is a typical third-generation wide bandgap semiconductor. Compared with silicon-based power devices, it has the advantages of high voltage resistance, high temperature resistance, fast switching speed, high thermal conductivity and low on-resistance. Therefore, it is gradually used in important fields such as new energy, photovoltaic power generation, and rail transportation. However, with the continuous improvement of the power density of silicon carbide modules and the increasingly harsh operating environment, its effective heat dissipation ability has become the key to long-term reliable and stable operation.

[0003] In view of the heat dissipation problem of modern silicon carbide power modules, double-sided packaging and double-sided heat dissipation structures are currently one of the most effective solutions. Specifically, the traditional single-sided packaging and single-sided heat dissipation structure uses a DCB (Direct Copper Bond) substrate or an AMB (Active Metal Brazing) substrate only on one side, and the bottom surface of the power semiconductor chip is connected to the DCB or AMB substrate, and then a heat sink is installed outside the substrate on this side to achieve heat dissipation on the bottom surface of the chip; the double-sided packaging and double-sided heat dissipation power module still uses a DCB substrate or an AMB substrate on the other side to replace the bonding wires in the power circuit, so that the top and bottom surfaces of the power semiconductor are connected to the DCB or AMB substrate, and then heat sinks are installed on both sides of the substrate, which can increase the heat dissipation channel on the top surface of the chip and significantly improve the heat dissipation efficiency of the module.

[0004] However, firstly, cooling components such as radiators are generally much heavier than the module itself. Compared with single-sided heat dissipation, the double-sided packaging and double-sided heat dissipation module structure increases the number of radiators, resulting in an increase in the total weight of the system and is not conducive to improving the power density. Secondly, since the top and bottom surfaces of the chip are connected to the DCB substrate or AMB substrate, the thermal stress problem caused by the mismatch of the coefficient of thermal expansion (CTE) between the chip and the substrate is more significant during operation, and the internal solder layer of the module may fail such as peeling or breaking, threatening the long-term operation reliability of the module. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a single-sided and double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module, so as to achieve an efficient and lightweight design that improves the heat dissipation efficiency and reduces the total weight of the module and the heat dissipation system, and improves the thermal stress distribution of the module, thereby enhancing the operating reliability of the SiC power module.

[0006] The technical solution adopted by the present invention is:

[0007] 1. A single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module

[0008] The single-double-sided composite heat dissipation structure includes a metal plate, a double-sided packaged silicon carbide power module and a radiator arranged in sequence from top to bottom, the metal plate and the radiator are respectively connected to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module, and the two sides of the bottom surface of the metal plate are connected to the top surface of the radiator.

[0009] The metal plate adopts a bent metal plate, and the cross-sectional shape of the bent metal plate is arched. The bent metal plate is mainly composed of a central protrusion, two edge portions and two arc-shaped transition connection portions; the two edge portions are respectively located on both sides of the central protrusion, and the two edge portions are respectively connected to the central protrusion through two arc-shaped transition connection portions. The bottom surface of the central protrusion is connected to the top surface of the double-sided packaged silicon carbide power module, and the bottom surface of the edge portion is connected to the top surface of the heat sink. The arc-shaped transition connection portion adopts an inwardly concave arc plate. The inwardly concave arc plate specifically means that for the arc-shaped cross-section of the arc-shaped transition portion, the center of the arc shape is located above the edge portion.

[0010] Alternatively, the metal plate is a slotted metal plate with an opening facing downward, the cross-sectional shape of the slotted metal plate is slot-shaped, the inner top surface of the metal plate is connected to the top surface of the double-sided packaged silicon carbide power module, the two inner side surfaces of the metal plate are respectively connected to the two side surfaces of the double-sided packaged silicon carbide power module, and the lower end surface of the metal plate is connected to the top surface of the radiator.

[0011] In a specific implementation, the metal plate is integrally processed by a metal bending process.

[0012] The radiator is a liquid cooling radiator or an air cooling radiator.

[0013] The metal plate and the heat sink are respectively connected and closely fitted to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module, and the two sides of the bottom surface of the metal plate are connected and closely fitted to the top surface of the heat sink. The connection method includes applying thermal interface material, solder welding or sintering. The thermal interface material includes silicone grease, and the sintering includes nano-silver pressure sintering.

[0014] 2. A size optimization method for a single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module comprises the following steps:

[0015] 1) Using finite element analysis software to establish a physical model of the single-double-sided composite heat dissipation structure;

[0016] 2) In the physical model of the single-double-sided composite heat dissipation structure, the room temperature is set to 25° C., and a heat load is applied to the internal chip of the double-sided packaged silicon carbide power module;

[0017] Wherein, the heat load is determined according to the power consumption parameters of the target double-sided packaged silicon carbide power module;

[0018] 3) By performing a thermal-mechanical coupling analysis on the physical model of the single-double-sided composite heat dissipation structure, a temperature distribution diagram of the single-double-sided composite heat dissipation structure when metal plates of different thicknesses are used, an internal temperature distribution diagram of the single-double-sided composite heat dissipation structure, and an equivalent stress distribution diagram of the solder layer are obtained;

[0019] In the step 3), the thickness h of the metal plate ranges from 1 mm to 10 mm.

[0020] 4) obtaining a first relationship curve between the chip junction temperature and the metal plate thickness according to the internal temperature distribution diagram of the heat dissipation structure corresponding to the metal plates of different thicknesses, and obtaining a second relationship curve between the maximum equivalent stress of the solder layer and the thickness of the metal plate according to the equivalent stress distribution diagram of the solder layer;

[0021] 5) According to the target chip junction temperature and the target maximum equivalent stress of the solder layer, the first relationship curve and the second relationship curve are combined to obtain the optimal metal plate thickness that simultaneously meets the target chip junction temperature and the target maximum equivalent stress of the solder layer.

[0022] The single-double-sided composite heat dissipation structure proposed in the present invention improves the thermal stress of the module and enhances the working reliability of the module while maintaining the heat dissipation efficiency and the lightweight design of the system.

[0023] The beneficial effects of the present invention are:

[0024] 1. The single-double-sided composite heat dissipation structure provided by the present invention uses the top metal plate to replace one side of the radiator in the conventional double-sided cooling structure, which makes the total weight of the module and the entire heat dissipation system lighter on the one hand, and reduces the external pump power loss by half on the other hand, reducing the system cost. At the same time, compared with the conventional double-sided cooling structure, the heat dissipation structure proposed by the present invention can also ensure efficient heat dissipation performance.

[0025] 2. The single-double-sided composite heat dissipation structure provided by the present invention optimizes the thickness of the top metal plate, thereby making the size and volume of the module and the entire heat dissipation system smaller, which is beneficial to improving the power density of power electronic equipment.

[0026] 3. The single-double-sided composite heat dissipation structure provided by the present invention can not only ensure the heat dissipation effect, but also reduce the stress of the internal chip solder layer during long-term operation of the power module through the constraint of the metal plate, and further improve the reliability of the internal solder layer of the module. Compared with the conventional double-sided cooling structure, the maximum equivalent stress of the solder layer between the chip and the substrate is smaller, and the deformation of the solder layer is also smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a single-double-sided composite heat dissipation structure based on a slotted metal plate in the present invention.

[0028] Figure 2 It is a two-dimensional schematic diagram of the single-double-sided composite heat dissipation structure based on the slotted metal plate in the present invention.

[0029] Figure 3 It is a schematic diagram of a single-double-sided composite heat dissipation structure based on a bent metal plate in the present invention.

[0030] Figure 4 It is a two-dimensional schematic diagram of the single-double-sided composite heat dissipation structure based on the bent metal plate in the present invention.

[0031] Figure 5 This is a simulated temperature distribution diagram of a single-double-sided composite heat dissipation structure based on a slotted metal plate in an embodiment of the present invention.

[0032] Figure 6 This is a diagram showing the internal temperature distribution of a simulation module of a single-double-sided composite heat dissipation structure based on a slotted metal plate in an embodiment of the present invention.

[0033] Figure 7 This is a diagram showing the equivalent stress distribution of the simulated solder layer of the single- and double-sided composite heat dissipation structure based on the slotted metal plate in an embodiment of the present invention.

[0034] Figure 8 It is a simulated temperature distribution diagram of the double-sided liquid cooling structure in the comparative example of the present invention.

[0035] Fig. 9 This is a diagram showing the internal temperature distribution of a simulation module of a double-sided liquid cooling structure in a comparative example of the present invention.

[0036] Fig.10 This is a diagram showing the equivalent stress distribution of the simulated welding layer of the double-sided liquid cooling structure in the comparative example of the present invention.

[0037] Among them, 1. metal plate, 2. double-sided packaged silicon carbide power module, 3. heat sink. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The present invention proposes a single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module. The upper and lower sides of the double-sided packaged silicon carbide power module adopt DCB or AMB substrates to achieve double-sided packaging. In the structure of the present invention, a radiator is installed only on one side of the substrate (defined as side A) of the double-sided packaged silicon carbide power module, and a metal plate is installed on the other side of the substrate (defined as side B). The heat is conducted to the radiator on side A through the metal plate, thereby achieving single-double-sided composite heat dissipation.

[0039] like Figure 1 and Figure 2As shown, the single-double-sided composite heat dissipation structure includes a metal plate 1, a double-sided packaged silicon carbide power module 2 and a heat sink 3 arranged in sequence from top to bottom. The metal plate 1 and the heat sink 3 are respectively connected to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module 2, and the two sides of the bottom surface of the metal plate 1 are connected to the top surface of the heat sink 3. When the double-sided packaged silicon carbide power module 2 is working, part of the heat generated by the internal chip is directly transferred to the heat sink 3 on one side, and the other part is indirectly transferred to the heat sink 3 by the slotted or bent metal plate 1 connected to it on the other side, and then the heat is taken away by the heat sink 3.

[0040] The metal plate 1 can be in different shapes such as a slotted metal plate or a bent metal plate, and its main purpose is to ensure a stable connection between the three. In a specific implementation, the shape of the metal plate 1 should meet the fixing and connection requirements of the structure. The thickness of the metal plate 1 is less than the thickness of the radiator 3. Therefore, the single-double-sided composite heat dissipation structure of the present invention effectively reduces the vertical height of the heat dissipation structure.

[0041] Optionally, the metal plate 1 is a bent metal plate, the cross-section of the bent metal plate is arched, and the bent metal plate is mainly composed of a central protrusion, two edge portions, and two arc-shaped transition connecting portions. The two edge portions are located on both sides of the central protrusion, and the two edge portions are connected to the central protrusion through two arc-shaped transition connecting portions. The bottom surface of the central protrusion is connected to the top surface of the double-sided packaged silicon carbide power module 2, and the bottom surface of the edge portion is connected to the top surface of the heat sink 3. Figure 3 and Figure 4 As shown, the arc-shaped transition connection portion adopts an inwardly concave arc-shaped plate. The inwardly concave arc-shaped plate specifically means that for the arc-shaped cross section of the arc-shaped transition portion, the center of the arc shape is located above the edge portion.

[0042] In a specific implementation, the metal plate 1 can be processed by using a metal bending process or other integrated process.

[0043] Optionally, the metal plate 1 is a slotted metal plate with an opening facing downward, and the cross-sectional shape of the slotted metal plate is slot-shaped. The inner top surface of the metal plate 1 is connected to the top surface of the double-sided packaged silicon carbide power module 2, and the two inner side surfaces of the metal plate 1 are respectively connected to the two side surfaces of the double-sided packaged silicon carbide power module 2, and the lower end surface of the metal plate 1 is connected to the top surface of the heat sink 3.

[0044] The radiator 3 may be a liquid cooling radiator or an air cooling radiator.

[0045] The metal plate 1 may be made of, but is not limited to, copper or other metals, alloys or metal composite materials with high thermal conductivity.

[0046] Furthermore, the metal plate 1 and the heat sink 3 are respectively connected and fixed to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module 2, and the two sides of the bottom surface of the metal plate 1 are connected and fixed to the top surface of the heat sink 3. The connection method can be applying thermal interface material, soldering or sintering.

[0047] The specific embodiments of the present invention are as follows:

[0048] This embodiment provides a Figure 1 The single-sided and double-sided composite heat dissipation structure shown in the figure, the material of the metal plate 1 is copper, and the thickness h of the middle part of the slotted metal plate is 3mm ( Figure 2 ), and the heat sink 3 is a liquid cooling heat sink. The metal plate 1 and the heat sink 3 are respectively connected to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module 2, and between the two sides of the bottom surface of the metal plate 1 and the top surface of the heat sink 3, through nano silver pressure sintering to achieve interconnection, and the three components are connected and fixed, and constrained to each other, thereby reducing the internal thermal stress of the module when it is working, thereby improving the reliability of the power module.

[0049] Comparative Example

[0050] This comparative example provides a Figure 5 The double-sided liquid cooling structure shown. A liquid cooling radiator is arranged on each side of the double-sided packaged silicon carbide power module 2.

[0051] Next, the temperature and stress distribution of the single-double-sided composite heat dissipation structure in the embodiment of the present invention is simulated by simulation means, and the specific process is as follows:

[0052] 1) Use finite element analysis software to establish a physical model of the single-double-sided composite heat dissipation structure;

[0053] 2) In the physical model of the single-double-sided composite heat dissipation structure, the room temperature is set to 25°C, and a heat load of 100W is applied to the internal chip of the double-sided packaged silicon carbide power module 2;

[0054] 3) By performing a thermal-mechanical coupling analysis on the physical model of the single-double-sided composite heat dissipation structure, a temperature distribution diagram of the single-double-sided composite heat dissipation structure, an internal temperature distribution diagram of the single-double-sided composite heat dissipation structure, and an equivalent stress distribution diagram of the solder layer are obtained when the metal plate 1 has different thicknesses (between 1 mm and 10 mm);

[0055] 4) obtaining a first relationship curve between the chip junction temperature and the metal plate thickness according to the internal temperature distribution diagram of the heat dissipation structure corresponding to the metal plates 1 of different thicknesses, and obtaining a second relationship curve between the maximum equivalent stress of the solder layer and the thickness of the metal plate according to the equivalent stress distribution diagram of the solder layer;

[0056] 5) According to the target chip junction temperature and the target maximum equivalent stress of the solder layer, the first relationship curve and the second relationship curve are combined to obtain the optimal metal plate thickness that simultaneously meets the target chip junction temperature and the target maximum equivalent stress of the solder layer.

[0057] In addition, the present invention also uses the above simulation process to simulate the temperature and stress distribution of the double-sided liquid cooling structure in the comparative example of the present invention. The simulation results of the thermal-mechanical coupling analysis of the embodiment of the present invention and the comparative example are as follows: Figures 5 to 10 shown.

[0058] The simulation results show that for the single-double-sided composite heat dissipation structure in the embodiment of the present invention, the thicker the metal plate, the better the heat dissipation effect. When the thickness of the metal plate is 3mm, the heat dissipation effect is comparable to that of the double-sided liquid cooling structure. At this time, the thermal performance of the single-double-sided composite heat dissipation structure in the embodiment of the present invention and the double-sided liquid cooling heat dissipation structure in the comparative example of the present invention are shown in the following table:

[0059] structure <![CDATA[Chip junction temperature T max > Maximum equivalent (Von-Mises) stress of the solder layer Single-sided and double-sided composite heat dissipation structure 123.3℃ 126.9MPa Double-sided liquid cooling structure 120.8℃ 137.4MPa

[0060] from Figure 5 and Figure 6 It can be seen that under the double-sided liquid cooling structure, the chip junction temperature is 120.8℃. Figure 8 and Fig. 9 It can be seen that the chip junction temperature under the single-double-sided composite heat dissipation structure is 123.3° C. Compared with the two structures, the temperature difference is only 2.5° C., indicating that the single-double-sided composite heat dissipation structure proposed in the present invention can also ensure the heat dissipation efficiency of the double-sided packaged silicon carbide power module.

[0061] Depend on Figure 7 and 10 By comparison, the maximum equivalent stress of the single-double-sided composite heat dissipation structure is lower, which means that the structure further reduces the thermal stress of the internal solder layer of the module without losing the heat dissipation performance, which is beneficial to the long-term normal operation of the module.

[0062] In summary, the single-double-sided composite heat dissipation structure provided by the present invention can significantly improve the heat dissipation efficiency compared with single-sided packaging and single-sided heat dissipation structures under the condition that the total weight of the module and the heat dissipation system is similar; compared with double-sided packaging and double-sided heat dissipation structures, under the condition that the heat dissipation efficiency is similar, it can reduce the total weight and volume size of the module and the heat dissipation system, which is conducive to improving the power density. In addition, the radiator is connected on both sides of the metal plate to play a mutual constraint role. Compared with traditional double-sided packaging and double-sided heat dissipation structures, it can improve the thermal stress of the module and improve the operational reliability.

Claims

1. A single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module, characterized in that: The single-double-sided composite heat dissipation structure comprises a metal plate (1), a double-sided packaged silicon carbide power module (2) and a heat sink (3) arranged in sequence from top to bottom, the metal plate (1) and the heat sink (3) being respectively connected to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module (2), and the two sides of the bottom surface of the metal plate (1) being connected to the top surface of the heat sink (3).

2. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 1, characterized in that: The metal plate (1) is a bent metal plate, the cross-section of which is arched, and the bent metal plate mainly consists of a central protruding portion, two edge portions, and two arc-shaped transition connecting portions; the two edge portions are respectively located on both sides of the central protruding portion, and the two edge portions are respectively connected to the central protruding portion through the two arc-shaped transition connecting portions; the bottom surface of the central protruding portion is connected to the top surface of the double-sided packaged silicon carbide power module (2), and the bottom surface of the edge portion is connected to the top surface of the heat sink (3).

3. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 2, characterized in that: The arc-shaped transition connection portion adopts an inwardly concave arc-shaped plate.

4. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 1, characterized in that: The metal plate (1) is a slotted metal plate with an opening facing downward, the cross-section of the slotted metal plate is in a slot shape, the inner top surface of the metal plate (1) is connected to the top surface of the double-sided packaged silicon carbide power module (2), the two inner side surfaces of the metal plate (1) are respectively connected to the two side surfaces of the double-sided packaged silicon carbide power module (2), and the lower end surface of the metal plate (1) is connected to the top surface of the heat sink (3).

5. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 1, characterized in that: The radiator (3) is a liquid-cooled radiator or an air-cooled radiator.

6. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 1, characterized in that: The metal plate (1) and the heat sink (3) are respectively connected to the top substrate and the bottom substrate of the double-sided packaged silicon carbide power module (2), and both sides of the bottom surface of the metal plate (1) are connected to the top surface of the heat sink (3).

7. The single-double-sided composite heat dissipation structure of a double-sided packaged silicon carbide power module according to claim 6, characterized in that: Connection methods include applying thermal interface materials, soldering or sintering.

8. A size optimization method for the single-double-sided composite heat dissipation structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) Using finite element analysis software to establish a physical model of the single-double-sided composite heat dissipation structure; 2) In the physical model of the single-double-sided composite heat dissipation structure, the room temperature is set to 25° C., and a heat load is applied to the internal chip of the double-sided packaged silicon carbide power module (2); 3) by performing a thermal-mechanical coupling analysis on the physical model of the single-double-sided composite heat dissipation structure, a temperature distribution diagram of the single-double-sided composite heat dissipation structure, an internal temperature distribution diagram of the single-double-sided composite heat dissipation structure, and an equivalent stress distribution diagram of the solder layer are obtained when metal plates (1) of different thicknesses are used; 4) obtaining a first relationship curve between the junction temperature of the chip and the thickness of the metal plate according to the internal temperature distribution diagram of the heat dissipation structure corresponding to the metal plates (1) of different thicknesses, and obtaining a second relationship curve between the maximum equivalent stress of the solder layer and the thickness of the metal plate according to the equivalent stress distribution diagram of the solder layer; 5) According to the target chip junction temperature and the target maximum equivalent stress of the solder layer, the first relationship curve and the second relationship curve are combined to obtain the optimal metal plate thickness that simultaneously meets the target chip junction temperature and the target maximum equivalent stress of the solder layer.

9. The size optimization method according to claim 8, characterized in that: In the step 3), the thickness of the metal plate (1) ranges from 1 mm to 10 mm.

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