A high power density hybrid encapsulated SIC module

Abstract

The present invention relates to the technical field of power modules, and particularly relates to a high-power-density hybrid encapsulated SIC module. The high-power-density hybrid encapsulated SIC module includes a heat dissipation substrate, a chip assembly, and a housing assembly. The heat dissipation column assembly includes a first heat dissipation column, a second heat dissipation column, and a third heat dissipation column. The coolant is forced to flow under the chip through the second heat dissipation column located on the center line and the second heat dissipation columns 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 utilization of cooling resources. The housing assembly includes a housing, liquid epoxy, and silicone gel. A buffer zone is provided on the inner side wall of the housing, and the liquid epoxy flows into the buffer zone. The buffer zone delays the path of moisture penetration along the interface, decomposes the unidirectional stress into multiple-directional micro deformations, and solves the problem of poor reliability of delamination of the power module in high-temperature and high-humidity environments.

Description

Technical Field

[0001] The present invention relates to the technical field of power modules, and particularly to a high-power-density hybrid potting SIC module. Background Art

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

[0003] In terms of the packaging process, traditional power modules mostly use a single potting material (such as liquid epoxy resin or silicone gel) for sealing. Although it can meet the basic insulation and protection requirements, it is difficult to balance cost and reliability. For example, the potting cost of liquid epoxy resin is several times higher than that of silicone gel, and its Young's modulus is relatively large, which will generate greater stress on the SIC chip when used in a large area; while silicone gel has weak anti-vibration ability and poor mechanical strength when used alone. In terms of the packaging structure, the existing modules are prone to delamination problems between the potting material and the housing in high-temperature and high-humidity environments, seriously affecting long-term reliability. Considering the issues of power density and stray inductance, 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, since the heat generated by the chips in the power module during operation is much greater than that of other electronic components such as signal pins, the heat generation in different regions of the power module is different. Most of the existing heat dissipation fins are evenly arranged, resulting in poor heat dissipation effect in high-heat-generation regions and excessive heat dissipation effect in low-heat-generation regions. 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 encapsulated SIC module, the high-power density hybrid encapsulated SIC module includes a heat dissipation substrate, a chip component disposed on the heat dissipation substrate, and a housing component disposed on the heat dissipation substrate. The heat dissipation substrate is provided with a heat dissipation column component on a side facing away from the chip component. The heat dissipation column component includes at least two first heat dissipation columns disposed on the heat dissipation substrate, a plurality of second heat dissipation columns disposed 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 strip-shaped and the extending direction is parallel to the flowing direction of the coolant. Two of the 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 flowing direction of the coolant. One end of the two first heat dissipation columns facing each other is serrated. The second heat dissipation columns are disposed on the center line of the heat dissipation substrate and on both sides of the heat dissipation substrate. The housing component includes a housing disposed on the heat dissipation substrate, a liquid epoxy disposed in the housing, and a silicone gel disposed in the housing. A buffer zone is provided on the inner side wall of the housing. The buffer zone includes a first buffer groove provided on the inner side wall of the housing and a second buffer groove connected to the first buffer groove. One end of the first buffer groove communicates with the inner side wall of the housing, and the other end is connected to the second buffer groove. One end of the second buffer groove communicates with the bottom of the housing. During encapsulation, the liquid epoxy flows into the buffer zone, first the liquid epoxy is encapsulated to fill the chip component, and then the silicone gel is covered and encapsulated.

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

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

[0008] Further, one end of the Ac terminal is connected to the AMB substrate, and the other end passes through the housing component. One end of the DC negative terminal and the DC positive terminal is connected to the AMB substrate, and the other end passes through the housing component. 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 form a stacked busbar structure.

[0009] Further, an opening for passing through the signal pin is provided at the centers of the DC negative terminal and the DC positive terminal.

[0010] Further, the housing has a rectangular frame structure with a hollow center.

[0011] Further, the first buffer groove and the second buffer groove are perpendicularly connected to each other, and the cross-section of the buffer area is in an L-shaped structure.

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

[0013] Compared with the prior art, in the heat dissipation column assembly of the high-power density hybrid encapsulated SIC module provided by the present invention, the second heat dissipation columns located on the center line and the second heat dissipation columns located on both sides force the coolant to flow under the chip, 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 utilization of cooling resources. The liquid epoxy and the silicone gel are encapsulated in two layers. First, the liquid epoxy is encapsulated to fill the main structure, and then the silicone gel is covered as the outer layer. Combining the rigidity and excellent insulation of epoxy with the advantages of low modulus, low cost, and moisture and heat resistance of silicone gel, it not only protects the internal devices but also avoids the performance shortcoming of a single material. In addition, in order to prevent delamination during use, a buffer area is provided on the inner side wall of the housing. One end of the first buffer groove communicates with the inner side wall of the housing, and the other end is connected to the second buffer groove. One end of the second buffer groove communicates with the bottom of the housing, so that the liquid epoxy can flow into the buffer area during encapsulation. The cross-section of the buffer area is in an L-shaped structure, forming a flexible transition layer when the liquid epoxy is filled during encapsulation. For moisture penetration, it delays the path of moisture penetration along the interface, making the moisture need to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of the adhesive layer by moisture. For stress accumulation, the L-shaped structure of the buffer area decomposes the stress in a single direction into multiple directions of small deformations, avoiding stress concentration, and thus solving the problem of easy delamination and poor reliability of the power module in a high-temperature and high-humidity environment. Description of the Drawings

[0014] Figure 1 It is a schematic structural diagram of a high-power density hybrid encapsulated SIC module provided by the present invention.

[0015] Figure 2 is Figure 1 The exploded structural diagram of the high-power density hybrid encapsulated SIC module.

[0016] Figure 3 is Figure 1 The top view of the high-power density hybrid encapsulated SIC module.

[0017] Figure 4 is Figure 1 a cross-sectional view of a high-power density hybrid encapsulated SIC module.

[0018] Figure 5 is Figure 1 a schematic structural diagram of a chip component of a high-power density hybrid encapsulated SIC module. Specific embodiments

[0019] The following further elaborates on specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein does not limit the protection scope of the present invention.

[0020] As Figures 1 to 5 shown, it is a schematic structural diagram of a high-power density hybrid encapsulated SIC module provided by the present invention. The high-power density hybrid encapsulated 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 envisioned that the high-power density hybrid encapsulated SIC module further includes some other functional modules, such as connection components, mounting components, etc., which are well-known technologies to those skilled in the art and will not be elaborated herein.

[0021] On the side of the heat dissipation substrate 10 facing away from the chip component 20, there is a heat dissipation column component 11. The heat dissipation column component 11 is disposed corresponding to the components within the chip component 20, and conducts the heat generated during the operation of the chip component 20 to the heat dissipation column component 11. The specific description of the heat dissipation column component 11 will be described below in conjunction with the chip component 20. The heat dissipation column component 11 cooperates with a heat dissipation base (not shown in the figure) provided with a water channel. The heat dissipation column component 11 is immersed in the coolant within the water channel, thereby exchanging heat with the flowing coolant to carry away the chip heat, which should be prior art and will not be elaborated herein.

[0022] The chip component 20 includes an AMB substrate 21, a plurality of chips 22 disposed 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 disposed on the AMB substrate 21, a DC negative terminal 25 disposed on the AMB substrate 21, a DC positive terminal 26 disposed on the AMB substrate 21, and a plurality of signal pins 27 disposed on the AMB substrate 21.

[0023] The AMB substrate 21 is a ceramic substrate realized through active metal brazing technology. The AMB substrate 21 is formed by bonding ceramic and copper layers through an 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 realizing 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 a lower cost and can achieve larger-area metal interconnection. The chips 22 themselves should be prior art, and their structures and working principles will not be elaborated here.

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

[0026] The first heat dissipation column 111 is strip-shaped and its extending direction is parallel to the flowing direction of the coolant. The two 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 flowing direction of the coolant. The opposite ends of the two first heat dissipation columns 111 are serrated. The first heat dissipation column 111 is used to forcibly guide the water flow to the center of the module and pass under the chip 22, avoiding the ineffective circulation of the coolant in the edge area, ensuring the efficient utilization of the cooling resources. At the same time, the strip-shaped serrated heat dissipation column structure will disrupt the laminar state of the water flow, inducing the formation of turbulence in the coolant guided 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 chips 22 are arranged in multiple rows on both sides of the AMB substrate 21, the positions of the chips 22 are located between the first heat dissipation column 111 and the second heat dissipation column 112. Therefore, the coolant is forcibly guided under the chips 22 through the second heat dissipation column 112 on the center line and the second heat dissipation columns 112 on both sides, ensuring that the coolant fully covers the high-heat generation area. The third heat dissipation column 113 is uniformly arranged in a column on the side of the heat dissipation substrate 10 facing away from the chip assembly 20. The multiple third heat dissipation columns 113 are used to ensure a large area of contact with the coolant, ensuring the heat exchange effect. At the same time, the regular arrangement can form uniform flow channel gaps, cooperating with the guiding functions of the first heat dissipation column 111 and the second heat dissipation column 112, forcing the coolant to maximize the utilization of the heat dissipation capacity of the coolant when the cooling water flows intensively through the key area under the chip 22.

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

[0028] The Ac terminal 24 is used to output the converted alternating current of 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 an external DC power supply to jointly form a DC loop to power the module. One end of the DC negative terminal 25 and the DC positive terminal 26 is connected to the AMB substrate 21, and the other end passes 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 largely overlap and adopt a stacked design, so that the magnetic fluxes generated by the currents flowing in opposite directions up and down will cancel each other out, reducing the loop stray inductance, thus greatly reducing the loop stray inductance and meeting the requirements of the SIC module for high-frequency switching. An opening 28 for passing the signal pin 27 is provided at the center of the DC negative terminal 25 and the DC positive terminal 26, allowing the signal pin 27 to directly pass through the terminal without additionally occupying the module space, thereby optimizing the layout and significantly reducing the overall size of the module. At the same time, openings are made in areas with relatively low current density such as the geometric center of the terminal to ensure that the current-carrying capacity of the terminal will not be affected.

[0030] The signal pin 27 is vertically arranged on the AMB substrate 21 and functions to transmit signals and control instructions, 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 of the prior art and will not be elaborated here.

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

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

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

[0034] One end of the first buffer groove 341 communicates with the inner side wall of the housing 31, and the other end is connected to the second buffer groove 342. One end of the second buffer groove 342 communicates with the bottom of the housing 31, so that the liquid epoxy 32 can flow into the buffer area 34 during potting. The first buffer groove 341 and the second buffer groove 342 are perpendicularly connected to each other, so that the cross section of the buffer area 34 is in an L-shaped structure. Since it will be in a high-temperature and high-humidity environment during actual use, there are differences in the expansion coefficients of the potting material and the material of the housing 31. Different expansion rates during temperature changes are likely to cause interface stress accumulation. Coupled with the penetration of moisture along the interface between the potting material and the housing 31 into the bonding joint, it will ultimately lead to delamination at the connection between the potting material and the housing, reducing the module's sealing performance and reliability. Therefore, a buffer area 34 is formed on the inner wall of the housing 31 and the liquid epoxy 32 is filled during potting to form a flexible transition layer. For moisture penetration, it delays the path of moisture penetration along the interface, causing the moisture to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of the bonding layer by moisture. For stress accumulation, the buffer area 34 increases the contact area between the potting material and the housing 31, dispersing the stress. The L-shaped structure of the buffer area 34 decomposes the stress in a single direction into small deformations in multiple directions, avoiding stress concentration. At the same time, the corners of the L-shaped groove allow the liquid epoxy 32 to undergo small elastic deformations during thermal expansion and contraction, avoiding the peeling of the connection caused by stress concentration.

[0035] The height of the liquid epoxy 32 is greater than the height of the CLIP copper sheet 23, so as to completely seal the CLIP copper sheet 23 and the chip 22. First, the liquid epoxy 32 is potted to fill the chip assembly 20, and then the silicone gel 33 is covered and potted as the outer layer, so that the silicone gel 33 is potted on the liquid epoxy 32 for double-layer potting. The liquid epoxy 32 has high mechanical strength, excellent insulation and chemical corrosion resistance characteristics, but the cost is relatively high. When the dosage is large, it is easy to apply greater stress to the chip during the curing stage. Therefore, on the premise of ensuring the coverage of the bonding wires, the liquid epoxy 32 is used as the internal seal for potting the chip assembly 20 to ensure the insulation and anti-vibration performance of the chip assembly 20. The silicone gel 33 has the characteristics of low modulus, low cost, and heat and humidity resistance. Therefore, the silicone gel 33 is used as the external seal to buffer the thermal expansion and contraction stress and absorb the impact of vibration through the silicone gel 33, avoiding affecting the liquid epoxy 32 and the chip assembly 20 in the next layer. In addition, the dosage of the silicone gel 33 is reduced and it is only used as the outer layer, reducing the module cost on the premise of ensuring the reliability of the module.

[0036] Compared with the prior art, in the heat dissipation column assembly 11 of the high-power density hybrid encapsulated SIC module provided by the present invention, the second heat dissipation columns 112 located on the center line and the second heat dissipation columns 112 located on both sides force the coolant to flow under the chip 22, 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 utilization of cooling resources. The liquid epoxy 32 and the silicone gel 33 are encapsulated in two layers. First, the liquid epoxy 32 is encapsulated to fill the main structure, and then the silicone gel 33 is covered as the outer layer. Combining the rigidity and excellent insulation of epoxy with the advantages of low modulus, low cost, and moisture and heat resistance of silicone gel, it not only protects the internal devices but also avoids the performance shortcoming of a single material. In addition, in order to prevent delamination during use, a buffer area 34 is provided on the inner side wall of the housing 31. One end of the first buffer groove 341 is communicated with the inner side wall of the housing 31, and the other end is connected to the second buffer groove 342. One end of the second buffer groove 342 is communicated with the bottom of the housing 31, so that the liquid epoxy 32 can flow into the buffer area 34 during encapsulation. The cross section of the buffer area 34 is in an L-shaped structure, forming a flexible transition layer when the liquid epoxy 32 is filled during encapsulation. For moisture penetration, it delays the path of moisture penetration along the interface, making the moisture need to bypass the tortuous path of the L-shaped groove, thereby reducing the direct erosion of the adhesive layer by moisture. For stress accumulation, the L-shaped structure of the buffer area 34 decomposes the stress in a single direction into multiple small deformations in multiple directions, avoiding stress concentration, and thus solving the problem of poor reliability and easy delamination of the power module in a high-temperature and high-humidity environment.

[0037] The above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, or improvements within the spirit of the present invention are covered by 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: An opening for inserting the signal needle is provided at the center of the DC negative terminal and the DC positive terminal.

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.

Images