High-power-density hybrid potting SIC module

Abstract

The invention relates to the technical field of power modules, in particular to a high-power-density hybrid potting SIC module. The high power density hybrid potting SIC module includes a heat dissipation substrate, a chip assembly, and a housing assembly. The heat dissipation column assembly comprises a first heat dissipation column, a second heat dissipation column and a third heat dissipation column. The cooling liquid is forcibly guided to the position below the chip through the second heat dissipation columns located on the center line and the second heat dissipation columns located on the two sides, it is ensured that the cooling liquid fully covers the high heating area, invalid circulation of the cooling liquid in the edge area is avoided, and efficient utilization of cooling resources is ensured. The shell assembly comprises a shell, liquid epoxy and silica gel. A circle of buffer area is arranged on the inner side wall of the shell, and the liquid epoxy flows into the buffer area. The buffer zone delays the permeation path of moisture along the interface, decomposes the stress in a single direction into micro deformation in multiple directions, and solves the problem that the power module is easy to layer and poor in reliability in a high-temperature and high-humidity environment.

Description

Technical Field

[0001] The invention relates to the technical field of power modules, and in particular to a high power density mixed potting SIC module. Background Art

[0002] With the rapid development of power electronics technology, silicon carbide (SiC) power modules have been widely used in new energy, electric vehicles, industrial frequency conversion and other fields due to their high frequency, high temperature and high efficiency. However, the existing SiC power modules still have many technical bottlenecks in packaging technology, reliability, cost and power density, which restricts their large-scale application.

[0003] In terms of packaging technology, traditional power modules are mostly sealed with a single potting material (such as liquid epoxy resin or silicone gel). Although it can meet basic insulation and protection requirements, it is difficult to balance cost and reliability. For example, the cost of liquid epoxy resin potting is several times that of silicone gel, and the Young's modulus is large, which will cause greater stress on the SIC chip when used over a large area; while silicone gel has weak vibration resistance and poor mechanical strength when used alone. In terms of packaging structure, existing modules are prone to delamination of potting materials and shells in high temperature and high humidity environments, which seriously affects long-term reliability. Considering power density and stray inductance issues, how to give full play to the advantages of high-frequency switching and low loss of SIC wafers through layout optimization and large-area laminated busbar design. In terms of heat dissipation, because the heat generated by the chip in the power module during operation is much greater than that of other electronic components such as signal pins, the heat generated in different areas of the power module is different. Most of the heat dissipation fins in the existing technology are evenly arranged, resulting in poor heat dissipation in high-heat areas and excessive heat dissipation in low-heat areas. Summary of the invention

[0004] In view of this, the present invention provides a high power density hybrid potting SIC module to solve the above technical problems.

[0005] A high power density hybrid potting SIC module, the high power density hybrid potting SIC module comprises a heat dissipation substrate, a chip assembly arranged on the heat dissipation substrate, and a shell assembly arranged on the heat dissipation substrate. The heat dissipation substrate is provided with a heat dissipation column assembly on the side facing away from the chip assembly. The heat dissipation column assembly comprises at least two first heat dissipation columns arranged on the heat dissipation substrate, a plurality of second heat dissipation columns arranged on the heat dissipation substrate, and a plurality of third heat dissipation columns arranged in an array on the heat dissipation substrate. The first heat dissipation column is in a long strip shape and the extension direction is parallel to the flow direction of the coolant. The two first heat dissipation columns are located on both sides of the heat dissipation substrate, and the arrangement direction of the two first heat dissipation columns is perpendicular to the flow direction of the coolant. The ends of the two first heat dissipation columns facing each other are in a serrated shape, and the second heat dissipation columns are arranged on the center line of the heat dissipation substrate and on both sides of the heat dissipation substrate. The shell assembly comprises a shell arranged on the heat dissipation substrate, a liquid epoxy arranged in the shell, and a silicone gel arranged in the shell. A circle of buffer is arranged on the inner side wall of the shell. The buffer comprises a first buffer groove arranged on the inner side wall of the shell, and a second buffer groove connected to the first buffer groove. One end of the first buffer groove is connected to the inner wall of the shell, and the other end is connected to the second buffer groove. One end of the second buffer groove is connected to the bottom of the shell. During potting, the liquid epoxy flows into the buffer zone, and the chip assembly is first filled with the liquid epoxy, and then the silicone gel is covered and potted.

[0006] Furthermore, the chip assembly includes an AMB substrate, a plurality of chips arranged on the AMB substrate, a plurality of CLIP copper sheets connecting the AMB substrate and the chips, an Ac terminal arranged on the AMB substrate, a DC negative terminal arranged on the AMB substrate, a DC positive terminal arranged on the AMB substrate, and a plurality of signal pins arranged on the AMB substrate.

[0007] Furthermore, the chips are arranged in multiple rows on both sides of the AMB substrate, and the chips are connected to the AMB substrate using copper sintering technology.

[0008] Furthermore, one end of the Ac terminal is connected to the AMB substrate, and the other end passes through the shell assembly, one end of the DC negative terminal and the DC positive terminal are connected to the AMB substrate, and the other end passes through the shell assembly, the planes where the DC negative terminal and the DC positive terminal are located are parallel and spaced apart, and the DC negative terminal and the DC positive terminal constitute a laminated busbar structure.

[0009] Furthermore, openings for inserting the signal needle are provided at the centers of the DC negative terminal and the DC positive terminal.

[0010] Furthermore, the shell is a rectangular frame structure with a hollow center.

[0011] Furthermore, the first buffer groove and the second buffer groove are vertically connected to each other, and the cross-section of the buffer zone is an L-shaped structure.

[0012] Furthermore, the height of the liquid epoxy is greater than the height of the CLIP copper sheet.

[0013] Compared with the prior art, the heat dissipation column assembly of the high power density hybrid potting SIC module provided by the present invention forces the coolant to be directed to the bottom of the chip through the second heat dissipation column located on the center line and the second heat dissipation column located on both sides, ensuring that the coolant fully covers the high heat generation area, avoiding the ineffective circulation of the coolant in the edge area, and ensuring the efficient use of cooling resources. The liquid epoxy and the silicone gel are potted in two layers, first potting the liquid epoxy to fill the main structure, and then covering the silicone gel as the outer layer, combining the rigidity and excellent insulation of epoxy and the low modulus, low cost and moisture resistance of silicone gel, which not only protects the internal components, but also avoids the performance shortcomings of a single material. In addition, in order to prevent the phenomenon of stratification during use. A circle of buffer is set on the inner side wall of the shell. One end of the first buffer groove is connected to the inner side wall of the shell, and the other end is connected to the second buffer groove. One end of the second buffer groove is connected to the bottom of the shell, so that the liquid epoxy can flow into the buffer zone during potting. The cross section of the buffer zone is L-shaped, and the liquid epoxy is filled to form a flexible transition layer during potting. For moisture penetration, the path of moisture penetration along the interface is delayed, and moisture needs to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of moisture on the adhesive layer. For stress accumulation, the L-shaped structure of the buffer zone decomposes the stress in a single direction into small deformations in multiple directions, avoiding stress concentration, thereby solving the problem of poor reliability of power modules that are easy to delaminate in high temperature and high humidity environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the structure of a high power density hybrid potting SIC module provided by the present invention.

[0015] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the high power density hybrid potting SIC module.

[0016] Figure 3 for Figure 1 Top view of the high power density hybrid potted SIC module.

[0017] Figure 4 for Figure 1 Cross-sectional view of a high power density hybrid potted SIC module.

[0018] Figure 5 for Figure 1 Schematic diagram of the structure of the chip components of the high power density hybrid potting SIC module. DETAILED DESCRIPTION

[0019] The specific embodiments of the present invention are further described in detail below. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.

[0020] like Figures 1 to 5 As shown, it is a schematic diagram of the structure of the high power density hybrid potting SIC module provided by the present invention. The high power density hybrid potting SIC module includes a heat dissipation substrate 10, a chip component 20 disposed on the heat dissipation substrate 10, and a housing component 30 disposed on the heat dissipation substrate 10. It can be imagined that the high power density hybrid potting SIC module also includes some other functional modules, such as connection components, and installation components, etc., which are well known to those skilled in the art and will not be repeated here.

[0021] The heat dissipation substrate 10 is provided with a heat dissipation column assembly 11 on the side facing away from the chip assembly 20. The heat dissipation column assembly 11 corresponds to the component arrangement in the chip assembly 20, and conducts the heat generated by the chip assembly 20 when it is working to the heat dissipation column assembly 11. The heat dissipation column assembly 11 will be described in detail below in conjunction with the chip assembly 20. The heat dissipation column assembly 11 is matched with a heat dissipation base (not shown) with a water channel. The heat dissipation column assembly 11 is immersed in the coolant in the water channel, thereby exchanging heat with the flowing coolant to take away the heat of the chip. This should be a prior art and will not be described in detail here.

[0022] The chip assembly 20 includes an AMB substrate 21, a plurality of chips 22 arranged on the AMB substrate 21, a plurality of CLIP copper sheets 23 connecting the AMB substrate 21 and the chips 22, an Ac terminal 24 arranged on the AMB substrate 21, a DC negative terminal 25 arranged on the AMB substrate 21, a DC positive terminal 26 arranged on the AMB substrate 21, and a plurality of signal pins 27 arranged on the AMB substrate 21.

[0023] The AMB substrate 21 is a ceramic substrate realized by active metal brazing technology. The AMB substrate 21 is formed by combining ceramic and copper layers by active metal brazing process. The middle of the AMB substrate 21 is a ceramic layer that provides excellent insulation and thermal conductivity, and the upper and lower layers are copper layers for circuit connection and heat dissipation.

[0024] The chips 22 are arranged in multiple rows on both sides of the AMB substrate 21. The chips 22 are connected to the AMB substrate 21 using copper sintering technology. Compared with silver sintering, copper sintering has lower cost and can achieve metal interconnection over a larger area. The chip 25 itself should be prior art, and its structure and working principle will not be described in detail here.

[0025] The area of ​​the heat dissipation column assembly 11 is larger than the area of ​​the AMB substrate 21. The chip assembly 20 is provided with components with lower heat generation, such as the signal pin 27, and the chip 22 with higher heat generation. Therefore, in order to ensure that the coolant can flow through the heat dissipation column at the bottom of the chip 22, the heat dissipation column assembly 11 includes at least two first heat dissipation columns 111 arranged on the heat dissipation substrate 10, a plurality of second heat dissipation columns 112 arranged on the heat dissipation substrate 10, and a plurality of third heat dissipation columns 113 arranged in an array on the heat dissipation substrate 10.

[0026] The first heat dissipation column 111 is in the shape of a long strip and its extension direction is parallel to the flow direction of the coolant. Two of the first heat dissipation columns 111 are located on both sides of the heat dissipation substrate 10. The arrangement direction of the two first heat dissipation columns 111 is perpendicular to the flow direction of the coolant. The ends of the two first heat dissipation columns 111 facing each other are in a serrated shape. The first heat dissipation column 111 is used to force the water flow to be directed to the center of the module and pass under the chip 22 to avoid ineffective circulation of the coolant in the edge area and ensure efficient use of cooling resources. At the same time, the long serrated heat dissipation column will destroy the laminar state of the water flow and induce the formation of turbulence in the coolant directed under the chip 22. Turbulence can significantly improve the heat exchange efficiency between the fluid and the heat dissipation column, thereby accelerating the transfer of heat from the heat dissipation column to the cooling water. The second heat dissipation column 112 is arranged on the center line of the heat dissipation substrate 10 and on both sides of the heat dissipation substrate 10. In this embodiment, since the chip 22 is arranged in multiple rows on both sides of the AMB substrate 21, the position of the chip 22 is located between the first heat dissipation column 111 and the second heat dissipation column 112. Therefore, the second heat dissipation column 112 located on the center line and the second heat dissipation column 112 located on both sides force the coolant to be directed to the bottom of the chip 22, ensuring that the coolant fully covers the high-heating area. The third heat dissipation column 113 is evenly arranged in a row on the side of the heat dissipation substrate 10 facing away from the chip assembly 20. The plurality of third heat dissipation columns 113 are used to ensure a large area of ​​contact with the coolant to ensure the heat exchange effect. At the same time, the regular arrangement can form a uniform flow channel gap, and cooperate with the first heat dissipation column 111 and the second heat dissipation column 112 to force the cooling water to flow through the key area below the chip 22, and maximize the use of the heat dissipation capacity of the coolant through the third heat dissipation column 113.

[0027] The CLIP copper sheet 23 connects the chip 22 and the AMB substrate 21 , and the chip and the terminal are connected by welding a copper strip or copper sheet to the upper copper layer of the AMB substrate 21 .

[0028] The Ac terminal 24 is used to output the AC power converted by the module. One end of the Ac terminal 24 is connected to the AMB substrate 21 , and the other end passes through the housing assembly 30 .

[0029] The DC negative terminal 25 and the DC positive terminal 26 are respectively used to connect the negative and positive poles of the external DC power supply to form a DC circuit to power the module. One end of the DC negative terminal 25 and the DC positive terminal 26 are connected to the AMB substrate 21, and the other end is passed through the housing assembly 30. The planes where the DC negative terminal 25 and the DC positive terminal 26 are located are parallel and spaced apart. The negative power terminal 27 and the positive power terminal 26 overlap in a large area and adopt a laminated design, so that the magnetic flux generated by the upper and lower opposite currents will be offset, so that the circuit inductance is reduced, thereby greatly reducing the circuit inductance and adapting to the high-frequency switch requirements of the SIC module. The center of the DC negative terminal 25 and the DC positive terminal 26 is provided with an opening 28 for passing the signal pin 27, so that the signal pin 27 can pass directly through the terminal without occupying additional module space, thereby optimizing the layout and significantly reducing the overall size of the module. At the same time, a hole is opened in the geometric center of the terminal and other areas with low current density to ensure that the current carrying capacity of the terminal is not affected.

[0030] The signal pin 27 is vertically arranged on the AMB substrate 21 and plays the role of transmitting signals and control instructions. It is responsible for transmitting control signals from the control system to the module, thereby controlling the working state and output power of the module. The signal pin 27 should be prior art and will not be described in detail here.

[0031] The housing assembly 30 includes a housing 31 disposed on the heat dissipation substrate 10 , a liquid epoxy 32 disposed in the housing 31 , and a silicone gel 33 disposed in the housing 31 .

[0032] The housing 31 is a rectangular frame structure with a hollow center. The housing 31 is used to accommodate the chip assembly 20 and to encapsulate the liquid epoxy 32 and the silicone gel 33 .

[0033] The shell 31 is made of PPS material. A buffer zone 34 is arranged on the inner side wall of the shell 31. The buffer zone 34 includes a first buffer groove 341 arranged on the inner side wall of the shell 31, and a second buffer groove 342 connected to the first buffer groove 341.

[0034] One end of the first buffer groove 341 is connected to the inner wall of the shell 31, and the other end is connected to the second buffer groove 342. One end of the second buffer groove 342 is connected to the bottom of the shell 31, so that the liquid epoxy 32 can flow into the buffer zone 34 during potting. The first buffer groove 341 and the second buffer groove 342 are vertically connected to each other, so that the cross-section of the buffer zone 34 is an L-shaped structure. Due to the high temperature and high humidity environment in actual use, there is a difference in the expansion coefficient between the potting material and the material of the shell 31. The different expansion rates when the temperature changes are likely to cause the accumulation of interfacial stress. In addition, moisture penetrates along the interface between the potting material and the shell 31 and invades the bonding connection, which eventually causes the potting material and the shell to delaminate, reducing the sealing and reliability of the module. Therefore, a buffer zone 34 is formed on the inner wall of the shell 31 and the liquid epoxy 32 is filled to form a flexible transition layer during potting. For moisture penetration, the path of moisture penetration along the interface is delayed, so that moisture needs to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of moisture on the adhesive layer. For stress accumulation, the buffer zone 34 increases the contact area between the potting material and the shell 31 and disperses the stress. The L-shaped structure of the buffer zone 34 decomposes the stress in a single direction into small deformations in multiple directions to avoid stress concentration. At the same time, the corners of the L-shaped groove allow the liquid epoxy 32 to undergo a small elastic deformation during thermal expansion and contraction to avoid stress concentration leading to peeling of the connection.

[0035] The height of the liquid epoxy 32 is greater than the height of the CLIP copper sheet 23, so that the CLIP copper sheet 23 and the chip 22 are completely sealed. The liquid epoxy 32 is first encapsulated to fill the chip assembly 20, and then the silicone gel 33 is covered and encapsulated as an outer layer, so that the silicone gel 33 is encapsulated on the liquid epoxy 32 using a double-layer encapsulation. The liquid epoxy 32 has high mechanical strength, excellent insulation and chemical corrosion resistance, but the cost is high. When the amount is large, it is easy to apply a large stress to the chip during the curing stage. Therefore, the liquid epoxy 32 is used as the internal seal of the chip assembly 20 while ensuring that the bonding wire is covered, so as to ensure the insulation and vibration resistance of the chip assembly 20. The silicone gel 33 has the characteristics of low modulus, low cost, and moisture and heat resistance, so the silicone gel 33 is used as an external seal, and the silicone gel 32 buffers the thermal expansion and contraction stress and absorbs the impact of vibration to avoid affecting the liquid epoxy 32 and chip assembly 20 of the next layer. In addition, the amount of the silicone gel 33 is reduced and is only used as an outer layer, thereby reducing the module cost while ensuring the module reliability.

[0036] Compared with the prior art, the heat dissipation column assembly 11 of the high power density hybrid potting SIC module provided by the present invention forces the coolant to be directed to the bottom of the chip 22 through the second heat dissipation column 112 located on the center line and the second heat dissipation column 112 located on both sides, ensuring that the coolant fully covers the high heating area, avoiding the ineffective circulation of the coolant in the edge area, and ensuring the efficient use of cooling resources. The liquid epoxy 32 and the silicone gel 33 are potted in two layers. The liquid epoxy 32 is first potted to fill the main structure, and then the silicone gel 33 is covered as the outer layer. The rigidity and excellent insulation of epoxy and the low modulus, low cost and moisture and heat resistance of silicone gel are combined to protect the internal components and avoid the performance shortcomings of a single material. In addition, in order to prevent the phenomenon of stratification during use. A circle of buffer zone 34 is provided on the inner wall of the shell 31. One end of the first buffer groove 341 is connected to the inner wall of the shell 31, and the other end is connected to the second buffer groove 342. One end of the second buffer groove 342 is connected to the bottom of the shell 31, so that the liquid epoxy 32 can flow into the buffer zone 34 during potting. The cross-section of the buffer zone 34 is an L-shaped structure, and the liquid epoxy 32 is filled to form a flexible transition layer during potting. For moisture penetration, the path of moisture penetration along the interface is delayed, so that moisture needs to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of moisture on the adhesive layer. For stress accumulation, the L-shaped structure of the buffer zone 34 decomposes the stress in a single direction into small deformations in multiple directions, avoiding stress concentration, thereby solving the problem of poor reliability of power modules that are easy to delaminate in high temperature and high humidity environments.

[0037] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.

Claims

1. A high power density hybrid potting SIC module, which is matched with a heat dissipation base with a water channel, and heat is taken away from the chip by heat exchange through flowing coolant, characterized in that: The high power density hybrid potting SIC module includes a heat dissipation substrate, a chip component arranged on the heat dissipation substrate, and a shell component arranged on the heat dissipation substrate. The heat dissipation substrate is provided with a heat dissipation column component on the side facing away from the chip component. The heat dissipation column component includes at least two first heat dissipation columns arranged on the heat dissipation substrate, a plurality of second heat dissipation columns arranged on the heat dissipation substrate, and a plurality of third heat dissipation columns arranged in an array on the heat dissipation substrate. The first heat dissipation column is in an elongated strip shape and its extension direction is parallel to the flow direction of the coolant. Two of the first heat dissipation columns are located on both sides of the heat dissipation substrate. The arrangement direction of the two first heat dissipation columns is perpendicular to the flow direction of the coolant. The ends of the two first heat dissipation columns facing each other are in a serrated shape. The second heat dissipation column is arranged on the center line of the heat dissipation substrate and on both sides of the heat dissipation substrate. The shell component includes a shell arranged on the heat dissipation substrate, a liquid epoxy arranged in the shell, and a silicone gel arranged in the shell. A circle of buffer zone is arranged on the inner side wall of the shell. The buffer zone includes a first buffer groove arranged on the inner side wall of the shell, and a second buffer groove connected to the first buffer groove. One end of the first buffer groove is connected to the inner side wall of the shell, and the other end is connected to the second buffer groove. One end of the second buffer groove is connected to the bottom of the shell. During potting, the liquid epoxy flows into the buffer zone, and the chip component is first potted with the liquid epoxy to fill it, and then the silicone gel is covered and potted.

2. The high power density hybrid potting SIC module according to claim 1, characterized in that: The chip assembly includes an AMB substrate, a plurality of chips arranged on the AMB substrate, a plurality of CLIP copper sheets connecting the AMB substrate and the chips, an Ac terminal arranged on the AMB substrate, a DC negative terminal arranged on the AMB substrate, a DC positive terminal arranged on the AMB substrate, and a plurality of signal pins arranged on the AMB substrate.

3. The high power density hybrid potting SIC module according to claim 2, characterized in that: The chips are arranged in multiple rows on both sides of the AMB substrate, and the chips are connected to the AMB substrate by using copper sintering technology.

4. The high power density hybrid potting SIC module according to claim 2, characterized in that: One end of the Ac terminal is connected to the AMB substrate, and the other end passes through the shell assembly. One end of the DC negative terminal and the DC positive terminal are connected to the AMB substrate, and the other end passes through the shell assembly. The planes where the DC negative terminal and the DC positive terminal are located are parallel and spaced apart. The DC negative terminal and the DC positive terminal constitute a laminated busbar structure.

5. The high power density hybrid potting SIC module according to claim 2, characterized in that: The centers of the DC negative terminal and the DC positive terminal are provided with openings for penetrating the signal needle.

6. The high power density hybrid potting SIC module according to claim 1, characterized in that: The shell is in a rectangular frame structure with a hollow center.

7. The high power density hybrid potting SIC module according to claim 1, characterized in that: The first buffer groove and the second buffer groove are vertically connected to each other, and the cross section of the buffer zone is an L-shaped structure.

8. The high power density hybrid potting SIC module according to claim 2, characterized in that: The height of the liquid epoxy is greater than the height of the CLIP copper sheet.

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