Power module and power converter
By combining conductive pillars and conductive plates, the junction temperature fluctuation problem of power modules during high-frequency switching is solved, achieving higher output power and packaging stability, and reducing the risk of packaging warpage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2026-03-13
AI Technical Summary
Existing power modules experience large junction temperature fluctuations during high-frequency switching, requiring chip derating and preventing them from generating significant output power. Furthermore, the packaging lacks sufficient heat dissipation capabilities.
The structure employs a combination of conductive pillars and conductive plates. The conductive pillars absorb heat to reduce the chip temperature, while openings on the conductive plates reduce deformation and ensure connection stability. The combined support of the conductive pillars and conductive plates improves the mechanical strength and heat dissipation efficiency of the package.
It effectively reduces the transient junction temperature fluctuation of the chip, ensuring the stability and reliability of the power module's output power under high power consumption, and avoiding connection problems and warping caused by high junction temperature.
Smart Images
Figure CN121666071A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic device technology, and in particular to a power module and a power converter. Background Technology
[0002] Currently, power modules are widely used in industrial and automotive inverters. With the continuous improvement of the overall power efficiency of electric vehicles, while remaining constrained by vehicle size, increasing the power density of power modules has become a development trend.
[0003] To achieve higher power density in a power module, multiple chips must be connected in parallel within the same form factor, and the heat dissipation of the package must be enhanced to allow each chip to output a larger current. This means increased power consumption and heat flux density for each chip, resulting in larger junction temperature fluctuations and higher maximum transient junction temperatures during high-frequency switching operation. To reduce the power module's failure rate, the chips need to be dated, which limits the power module's ability to generate significant output power. Summary of the Invention
[0004] The purpose of this application is to provide a power module and a power converter to reduce junction temperature fluctuations, so that while reducing the failure rate of the power module, the first power chip does not need to be dated excessively due to transient high junction temperature, thus ensuring that the power module can generate greater output power.
[0005] A first aspect of this application provides a power module, comprising: a substrate, a first power chip, a first conductive post, and a first conductive plate. The substrate has a groove that divides the substrate into a first conductive region and a second conductive region. The first power chip is disposed on the first conductive region. The first conductive post is disposed on the side of the first power chip facing away from the substrate. The first conductive plate is disposed on the side of the first conductive post facing away from the substrate. The first conductive plate is used to connect the first conductive post and the second conductive region. The first conductive plate has a first opening along the thickness direction of the power module.
[0006] When the first power chip is operating, it generates heat. The first conductive post located between the first power chip and the first conductive plate can absorb heat, thereby reducing the actual operating temperature (i.e., junction temperature) of the first power chip. In other words, under conditions of instantaneous high power consumption, the first conductive post provides heat absorption and energy storage, reducing the maximum transient junction temperature of the first power chip. This ensures that the junction temperature fluctuation of the first power chip is small even under high power consumption, so that while reducing the power module failure rate, the first power chip does not need to be excessively derating due to transient high junction temperatures, ensuring that the power module can generate greater output power.
[0007] A first power chip disposed on a first conductive region can be electrically connected to a first conductive plate via a first conductive post, and the first conductive plate is electrically connected to a second conductive region. This achieves conductivity between the first power chip and the second conductive region. The first conductive plate also has a first opening. When the first conductive plate undergoes thermal expansion and contraction, the first opening can reduce the degree of deformation of the first conductive plate, preventing excessive deformation along the direction parallel to the substrate towards the surface of the first power chip. This prevents excessive deformation of the first conductive plate along the direction parallel to the substrate towards the surface of the first power chip from causing the first conductive post to tilt and pull on the first power chip, leading to cracking at the connection between the chip and the first conductive post, resulting in an unreliable connection between the first conductive post and the first power chip.
[0008] In one optional embodiment, the projection of the first opening in the thickness direction of the power module does not overlap with the projection of the first conductive post in the thickness direction of the power module. That is, the position of the first opening can avoid the connection position between the first conductive post and the first conductive plate, ensuring that the first opening does not affect the connection stability between the first conductive post and the first conductive plate.
[0009] In one optional embodiment, the distance between the first opening and the first conductive post along the first direction is less than a set threshold. The set threshold can be designed based on the specific dimensions of the power module and the degree of thermal deformation of the first conductive plate. For example, the set threshold can be any value between 0mm and 10mm. The first direction is perpendicular to the thickness direction of the power module. The first opening can reduce the degree of deformation of the portion of the first conductive plate located at the connection with the first conductive post, further reducing the tensile force on the first conductive post, preventing cracking at the connection between the chip and the first conductive post, and ensuring the connection stability between the first conductive post and the first power chip.
[0010] In one optional embodiment, a plurality of first openings are provided on the first conductive plate around the periphery of the connection between the first conductive plate and the first conductive post. By providing a plurality of first openings around the periphery of the connection between the first conductive plate and the first conductive post, the degree of deformation of the first conductive plate around the connection with the first conductive post is reduced, further reducing the tensile force on the first conductive post and ensuring the connection stability between the first conductive post and the first power chip.
[0011] In one optional embodiment, the thickness of the first conductive post is greater than the thickness of the first conductive plate along the thickness direction of the power module. In this case, the larger thickness of the first conductive post improves its heat absorption and energy storage effect.
[0012] In one optional embodiment, the power module further includes a molding compound that encapsulates the first power chip, the first conductive post, and the first conductive plate. The molding compound provides electrical insulation protection for the first power chip, the first conductive post, and the first conductive plate. Additionally, the molding compound provides some support, offering a degree of mechanical strength protection to the power module. A portion of the molding compound is disposed within the first opening. This ensures a more secure connection between the molding compound and the first conductive plate, preventing delamination between the molding compound and the first conductive plate and ensuring the electrical insulation function of the molding compound is maintained.
[0013] In one optional embodiment, the power module further includes a second conductive post, which is disposed between the second conductive region and the first conductive plate, and connects the second conductive region and the first conductive plate. The first power chip can be connected to the first conductive plate through the first conductive post, and the first conductive plate can then be connected to the second conductive region through the second conductive post. This achieves the connection between the first power chip and the second conductive region.
[0014] In one optional embodiment, the first conductive plate is arranged parallel to the substrate. Compared to some related technologies that use copper wire bonding or other methods for inter-chip conductivity, in this application, both the first and second conductive posts can support the first conductive plate. This parallel arrangement of the substrate and the first conductive plate ensures that the first conductive plate also provides support in the packaged power module, improving the anti-warping effect of the power module.
[0015] In one optional embodiment, the first conductive plate includes a first part and a second part, the first part being connected to a first conductive post, and the second part being bent toward a substrate and connected to a second conductive region.
[0016] The first power chip can be electrically connected to the first part of the first conductive plate via the first conductive post, and the second part of the first conductive plate can be electrically connected to the second conductive region, thereby achieving conductivity between the first power chip and the second conductive region. The second part of the first conductive plate can be bent directly downwards without the need for other structures to achieve conductivity with the second conductive region, saving materials.
[0017] In one optional embodiment, along the second direction, the width of the portion of the first part connected to the first conductive post is smaller than the width of the first conductive post. The second direction is perpendicular to the thickness direction of the power module. The smaller connection area between the first portion of the first conductive plate and the first conductive post results in a smaller tensile force on the first conductive post. This reduces the stress on the surface of the first power chip, lowering the risk of cracking at the connection between the first power chip and the first conductive post.
[0018] In one optional embodiment, the first conductive plate is made of a metallic material. For example, the first conductive plate is made of copper, a copper alloy, or the like. Using this material results in a low-cost first conductive plate that is easy to open the first opening.
[0019] In one optional embodiment, a solder layer is provided between the first conductive post and the first conductive plate. The solder layer is used to connect the first conductive post and the first conductive plate. The solder layer can be formed by a reflow soldering process to achieve the connection and conductivity between the first conductive post and the first conductive plate.
[0020] In another optional embodiment, the first conductive post is in contact with and fixed to the first conductive plate. The first conductive post and the first conductive plate can be directly welded and fixed by laser welding or ultrasonic welding to achieve connection and conduction between the first conductive post and the first conductive plate.
[0021] In one alternative embodiment, the first power chip has a gate. The gate of the first power chip is exposed above a first conductive post. This prevents the first conductive post from obscuring the gate of the first power chip, thus preventing the gate of the first power chip from being electrically connected to other components (such as a driver module).
[0022] In one optional embodiment, the material of the first conductive pillar includes a pure metal, an alloy, or a composite material. For example, the material of the first conductive pillar can be a pure metal, such as copper. The first conductive pillar using this material has low cost, high heat capacity, and high thermal conductivity, effectively absorbing the heat dissipated by the first power chip, resisting junction temperature fluctuations, and reducing the cost of the power module.
[0023] Alternatively, the first conductive pillar can be made of an alloy, such as a molybdenum-copper (MoCu) alloy. It can also be made of composite materials, such as aluminum silicon carbide (AlSiC) or copper diamond. The first conductive pillar made of these materials has a low coefficient of thermal expansion, preventing the expansion of the first conductive pillar from compressing and damaging the first power chip.
[0024] Alternatively, the first conductive post can also be a composite structure, for example, a portion of the first conductive post may be made of copper, and a portion may be made of MoCu alloy, etc. This application does not impose specific limitations.
[0025] In one optional embodiment, the first conductive pillar includes a first copper layer, a molybdenum-copper alloy layer, and a second copper layer connected in sequence. The first copper layer is connected to the first power chip, and the second copper layer is connected to the first conductive plate. Copper has a high heat capacity and high thermal conductivity, allowing the first copper layer connected to the first power chip to quickly absorb the heat released by the chip. The second copper layer connected to the first conductive plate can also transfer heat to the first conductive plate for heat dissipation. The molybdenum-copper alloy has a low coefficient of thermal expansion, and the layer between the first and second copper layers reduces the overall thermal expansion of the first conductive pillar. This prevents the expansion of the first conductive pillar from compressing and damaging the first power chip.
[0026] In one optional embodiment, the power module further includes a second power chip and a third conductive post. The second power chip is disposed in the second conductive region. The third conductive post is disposed on the side of the second power chip opposite to the second conductive region.
[0027] Under conditions of instantaneous high power consumption of the second power chip, the third conductive post can provide heat absorption and energy storage, reducing the maximum transient junction temperature of the second power chip. This ensures that the junction temperature fluctuation of the second power chip is small under high power consumption, so that while meeting the requirement of reducing the failure rate of the power module, the second power chip does not need to be excessively dated due to the transient high junction temperature, thereby further increasing the output power that the power module can generate.
[0028] In one optional embodiment, the power module further includes a first terminal, a second terminal, and a third terminal. The first terminal is electrically connected to a first conductive region. The second terminal is electrically connected to a third conductive post. The third terminal is electrically connected to a second conductive region. When the power module is operating, the first power chip and the second power chip can be alternately turned on. A battery is connected through the first and second terminals, and the power module converts DC to AC, which is then output through the third terminal. Alternatively, AC current can be input to the third terminal, converted to DC by the power module, and then DC current can be output through the first and second terminals. Along a direction parallel to the side surface of the substrate facing the first power chip, the first and second terminals are located on the same side of the substrate. Along a direction perpendicular to this direction and parallel to the side surface of the substrate facing the first power chip, the dimensions of the first and second terminals overlap, which optimizes the overall layout of the power module and helps to reduce the size of the power module.
[0029] In one optional embodiment, the groove further divides the substrate into a third conductive region, which is electrically connected to the second terminal. The power module also includes a second conductive plate and a fourth conductive post. The second conductive plate is disposed on the side of the third conductive post opposite to the second power chip and is connected to and conducts electricity with the third conductive post. The fourth conductive post is disposed between the second conductive plate and the third conductive region. The fourth conductive post is used to connect and conduct electricity between the second conductive plate and the third conductive region. Both the third and fourth conductive posts can provide support for the second conductive plate. The substrate and the second conductive plate are stacked, and the second conductive plate can also provide support, further improving the anti-warping effect of the power module.
[0030] In one optional embodiment, the second conductive plate has a second opening. When the second conductive plate undergoes thermal expansion and contraction, the second opening can reduce the degree of deformation of the second conductive plate, preventing excessive deformation along the direction parallel to the substrate and towards the surface of the second power chip. This prevents excessive deformation of the second conductive plate from exerting a force on the third conductive post along the same direction, thus avoiding cracking at the connection between the third conductive post and the second power chip.
[0031] A second aspect of this application provides a power converter, comprising: a heat sink and at least one of the aforementioned power modules, wherein the heat sink is disposed on a side of a substrate facing away from the first conductive plate. The power converter is used for AC / DC conversion. The heat sink is capable of dissipating heat from the power modules. Furthermore, the power converter described above has the same technical effects as the power modules provided in the foregoing embodiments, and will not be repeated here. Attached Figure Description
[0032] Figure 1 A schematic diagram of the structure of a vehicle provided in an embodiment of this application;
[0033] Figure 2 This is a schematic diagram of the structure of a power device provided in an embodiment of this application;
[0034] Figure 3 This is a schematic diagram of the structure of a power module provided in an embodiment of this application;
[0035] Figure 4 for Figure 3 The diagram shown is a structural schematic of the power module after removing the plastic encapsulation, first terminal, second terminal, third terminal, and pins, along direction A.
[0036] Figure 5 for Figure 4 Top view of the power module shown;
[0037] Figure 6 for Figure 3 The power module shown is a cross-sectional view along the P1-P2 direction;
[0038] Figure 7 for Figure 3 The diagram shown shows another structural representation of the power module after removing the plastic package, first terminal, second terminal, third terminal, and pins, along direction A.
[0039] Figure 8 for Figure 7 Top view of the power module shown;
[0040] Figure 9 for Figure 3 The diagram shown shows another structural representation of the power module after removing the plastic package, first terminal, second terminal, third terminal, and pins, along direction A.
[0041] Figure 10 An exploded view of a power module provided in an embodiment of this application;
[0042] Figure 11 for Figure 3 The diagram shown shows another structural representation of the power module after removing the plastic package, first terminal, second terminal, third terminal, and pins, along direction A.
[0043] Figure 12 An exploded view of another power module provided in an embodiment of this application.
[0044] Figure label:
[0045] 100-Vehicle; 01-Battery; 02-Power Converter; 03-Motor; 04-Wheel; 10-Power Module; 20-Heat Radiator; 101-First Terminal; 102-Second Terminal; 103-Third Terminal; 104-Pin; 105-Encapsulation; 106-Substrate; 1061-Groove; 1062-First Conductive Area; 1063-Second Conductive Area; 1064-Third Conductive Area; 107-First Power Core 108-First conductive post; 1081-First copper layer; 1082-Molybdenum-copper alloy layer; 1083-Second copper layer; 109-First conductive plate; 1091-First opening; 1092-First part; 1093-Second part; 110-Second conductive post; 111-Welding layer; 112-Second power chip; 113-Third conductive post; 114-Second conductive plate; 1141-Second opening; 115-Fourth conductive post. Detailed Implementation
[0046] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0047] In the following description, the terms "first," "second," "third," "fourth," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," "third," "fourth," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0048] In this application, unless otherwise expressly specified and limited, the term "connection" shall be interpreted broadly. For example, "connection" may be a fixed mechanical connection, a detachable mechanical connection, or an integral part; or, "connection" may be a direct connection or an indirect connection through an intermediate medium.
[0049] In this application, the words "exemplarily" and "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design that is described as "exemplarily" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplarily" and "for example" is intended to present the relevant concepts in a specific manner.
[0050] In the embodiments of this application, the terms "vertical" and "parallel" respectively indicate approximately vertical and approximately parallel within a certain error range. This error range can be a range where the deviation angle relative to absolute verticality and absolute parallelism is less than or equal to 5°, 8°, or 10°, respectively, and is not specifically limited here.
[0051] In the accompanying drawings of the embodiments of this application, components are represented by straight guide lines with arrows; parts are represented by only straight guide lines; and hollow structures such as cavities and openings are represented by curved guide lines.
[0052] This application implements, for example Figure 1 As shown, a vehicle 100 is provided. The vehicle 100 may include a battery 01 and a power converter 02 electrically connected to the battery 01. The battery 01 may be a power battery. The power converter 02 may be used for AC / DC power conversion.
[0053] Taking the power device 02 mentioned above, which may include an inverter, as an example, please refer to the following: Figure 1 Battery 01 outputs DC current to power converter 02. Power converter 02 converts the DC current from battery 01 into AC current and transmits it to electrical equipment such as motor 03 to power the equipment. Power device 02 can be a vehicle microcontroller unit (MCU) or a bidirectional on-board charger (OBC).
[0054] Continue reading Figure 1 The vehicle 100 may also include wheels 04. The motor 03 receives power from the power converter 02 and drives the wheels 04.
[0055] Alternatively, when the power converter 02 is applied in the vehicle 100, the power converter 02 can also be a rectifier. Alternatively, the power converter 02 can also be an on-board generator control unit (GCU).
[0056] The above example illustrates the application of the power converter 02 in vehicle 100. In other embodiments of this application, the power converter 02 can also be used in energy storage systems (such as photovoltaic systems, site energy, etc.) to convert the DC current of the battery into AC current output, or to convert AC current into DC current and transmit it to the battery to charge it.
[0057] The structure of the power converter 02 described above is illustrated below. Please refer to [link / reference]. Figure 2 The power converter 02 may include at least one power module 10 and a heat sink 20. The heat sink 20 is connected to the power module 10. The heat sink 20 is capable of dissipating heat from the power module 10.
[0058] The above implementation examples Figure 2 The illustration shows an example where a heat sink 20 is provided on one side of the power module 10. In other embodiments of this application, a heat sink 20 may also be provided on the other side of the power module 10. This application does not impose specific limitations on the embodiments.
[0059] For example, continue as follows Figure 2 As shown, the power converter 02 may include three power modules 10. The three power modules 10 are combined to form a three-phase inverter circuit. The three-phase inverter circuit is used to convert the DC power output from the battery 01 into three-phase AC power.
[0060] Of course, in other embodiments of this application, the number of power modules 10 may also be other numbers. This application does not impose specific limitations on the embodiments.
[0061] For ease of explanation, the following example uses the length direction of the power module 10 as the X direction, the width direction as the Y direction, and the thickness direction as the Z direction.
[0062] See Figure 3 In order to work with battery 01 (such as...) Figure 1As shown, the power module 10 may include a first terminal 101 and a second terminal 102. The first terminal 101 may be electrically connected to the positive terminal of the battery 01, and the second terminal 102 may be electrically connected to the negative terminal of the battery 01. Alternatively, the first terminal 101 may be electrically connected to the negative terminal of the battery 01, and the second terminal 102 may be electrically connected to the positive terminal of the battery 01.
[0063] To output alternating current, please refer to [further details]. Figure 3 The power module 10 may also include a third terminal 103. The third terminal 103 can be connected to the motor 03 (e.g., Figure 1 (As shown) Electrical connection, transmitting the AC current converted by power module 10 to motor 03.
[0064] In addition, please continue to refer to Figure 3 The power module 10 may also include pins 104, which can be used for electrical connection with external structures (such as drive modules, not shown in the figure), and pins 104 can transmit some control signals, etc.
[0065] Continue reading Figure 3 In order to provide electrical protection for the power module 10, the power module 10 may also include a molding compound 105, with a portion of the first terminal 101, a portion of the second terminal 102, a portion of the third terminal 103, and a portion of the pin 104 exposed in the molding compound 105 to facilitate connection with external structures.
[0066] See Figure 4 , Figure 4 for Figure 3The diagram shows a power module 10 after removing the encapsulation 105, first terminal 101, second terminal 102, third terminal 103, and pins 104, along direction A. The power module 10 may include a substrate 106, a first power chip 107, a first conductive post 108, a second conductive post 110, and a first conductive plate 109. The substrate 106 has a groove 1061 that divides the substrate 106 into a first conductive region 1062 and a second conductive region 1063. The first conductive region 1062 and the second conductive region 1063 are not directly conductive; for example, the encapsulation 105 disposed within the groove 1061 separates the first conductive region 1062 and the second conductive region 1063, preventing direct conductivity. The first power chip 107 is disposed on the first conductive region 1062. The first conductive post 108 is disposed on the first power chip 107. A first conductive plate 109 is disposed on the side of the first conductive post 108 facing away from the substrate 106 and is connected to the first conductive post 108. The first conductive plate 109 is used for electrical connection with the second conductive region 1063. A first power chip 107 disposed on the first conductive region 1062 can be electrically connected to the first conductive plate 109 through the first conductive post 108, and the first conductive plate 109 is electrically connected to the second conductive region 1063. This enables the first power chip 107 to conduct to the second conductive region 1063.
[0067] When the first power chip 107 is operating, it generates heat. The first conductive post 108, located between the first power chip 107 and the first conductive plate 109, can absorb heat, thereby reducing the actual operating temperature (i.e., junction temperature) of the first power chip 107. That is, under conditions of instantaneous high power consumption, the first conductive post 108 provides a heat absorption and energy storage effect, reducing the maximum transient junction temperature of the first power chip 107. This ensures that the junction temperature fluctuation of the first power chip 107 is small even under high power consumption, so that while reducing the failure rate of the power module 10, the first power chip 107 does not need to be excessively dated due to the transient high junction temperature, ensuring that the power module 10 can generate greater output power.
[0068] The above implementation example Figure 4 The illustration shows an example where the substrate 106 includes an insulating plate and metal layers located on both sides of the insulating plate. A groove 1061 is formed in the metal layer on one side of the insulating plate, dividing the metal layer into a first conductive region 1062 and a second conductive region 1063. In other embodiments of this application, the substrate 106 may include only one metal layer. Alternatively, the substrate 106 may also include an insulating plate and a metal layer located on one side of the insulating plate. The embodiments in this application are not specifically limited.
[0069] For example, radiator 20 (such as Figure 2 (As shown) is disposed on the side of the substrate 106 away from the first conductive plate 109 and is connected to the substrate 106.
[0070] See Figure 5 , Figure 5 for Figure 4 The top view of the power module 10 shown shows that the first conductive plate 109 has a first opening 1091 extending along the thickness direction Z of the power module 10. When the first conductive plate 109 undergoes thermal expansion and contraction, the first opening 1091 can reduce the degree of deformation of the first conductive plate 109, preventing deformation caused by the first conductive plate 109 extending parallel to the substrate 106 towards the first power chip 107 (e.g., ...). Figure 4 If the deformation of the surface of the first conductive post 108 (i.e., the direction on the XY plane) is too large, it will exert a force on the first conductive post 108 in a direction parallel to the surface of the substrate 106 toward the first power chip 107. This will cause the first conductive post 108 to have a tendency to tilt and pull on the first power chip 107, resulting in cracking at the connection between the chip and the first conductive post 108, and causing the connection between the first conductive post 108 and the first power chip 107 to be unreliable.
[0071] The above implementation example Figure 5 The illustration shows an example where the first opening 1091 is a through hole extending along the thickness direction Z of the power module 10. In other embodiments of this application, the first opening 1091 may also be a blind hole.
[0072] Continue reading Figure 5 The first opening 1091 is in the thickness direction Z of the power module 10 (e.g., Figure 4 The projection of the first opening 1091 (as shown) does not overlap with the projection of the first conductive post 108 in the thickness direction Z of the power module 10. That is, the opening position of the first opening 1091 can avoid the connection position between the first conductive post 108 and the first conductive plate 109, ensuring that the first opening 1091 will not affect the connection stability of the first conductive post 108 and the first conductive plate 109.
[0073] Continue reading Figure 5 Along the first direction (i.e., the direction on the XY plane), the distance between the first opening 1091 and the first conductive post 108 (as shown by the dotted line in the figure, which is blocked by the first conductive plate 109) is less than a set threshold. The set threshold can be designed according to the specific dimensions of the power module 10 and the degree of thermal deformation of the first conductive plate 109. For example, the set threshold can be any value between 0mm and 10mm. Also for example, the set threshold can be 0mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 5mm, 7mm, 10mm, etc. The first direction 1091 is perpendicular to the thickness direction Z of the power module 10 (e.g., ...). Figure 4(As shown). The first opening 1091 can reduce the deformation of the first conductive plate 109 at the connection with the first conductive post 108, further reduce the pulling effect on the first conductive post 108, prevent the connection between the first power chip 107 and the first conductive post 108 from cracking, and ensure the connection stability between the first conductive post 108 and the first power chip 107.
[0074] Continue reading Figure 5 A plurality of first openings 1091 are provided on the periphery of the connection between the first conductive plate 109 and the first conductive post 108. By providing multiple first openings 1091 around the periphery of the connection between the first conductive plate 109 and the first conductive post 108, the deformation of the first conductive plate 109 around the connection with the first conductive post 108 is reduced, further reducing the pulling effect on the first conductive post 108 and ensuring the connection stability between the first conductive post 108 and the first power chip 107.
[0075] The above implementation examples Figure 5 The illustration shows an example where four first openings 1091 are provided on the periphery of the connection between each first conductive post 108 and the first conductive plate 109. In other embodiments of this application, other numbers of first openings 1091 may be provided on the periphery of the connection between each first conductive post 108 and the first conductive plate 109, such as 1, 2, 3, 5, or 6. This application does not impose specific limitations on the embodiments.
[0076] Of course, the first opening 1091 can also be made at other locations on the first conductive plate 109. This application embodiment does not impose specific limitations.
[0077] Continue reading Figure 4 Along the thickness direction Z of the power module 10, the thickness h1 of the first conductive post 108 is greater than the thickness h2 of the first conductive plate 109. At this time, the thickness of the first conductive post 108 is larger, which improves the heat absorption and energy storage effect of the first conductive post 108.
[0078] See Figure 6 , Figure 6 for Figure 3The diagram shows a cross-sectional view of the power module 10 along the P1-P2 direction. The power module 10's encapsulation 105 covers the first power chip 107, the first conductive post 108, and the first conductive plate 109. The encapsulation 105 provides electrical insulation protection for the first power chip 107, the first conductive post 108, and the first conductive plate 109. Additionally, the encapsulation 105 provides some support, offering a degree of mechanical strength protection to the power module 10. A portion of the encapsulation 105 is disposed within the first opening 1091. This ensures a more secure connection between the encapsulation 105 and the first conductive plate 109, preventing delamination between the encapsulation 105 and the first conductive plate 109, which would affect the electrical insulation function of the encapsulation 105.
[0079] Continue reading Figure 6 The molding compound 105 is also disposed on the periphery of the substrate 106 and the first conductive plate 109. At this time, the molding compound 105 can ensure that the periphery of the substrate 106 and the first conductive plate 109 is insulated from the outside, and at the same time can increase the creepage distance of the edge portion of the substrate 106 and the first conductive plate 109 to prevent creepage, thereby improving electrical safety performance and meeting safety regulations.
[0080] The above implementation examples Figure 6 The illustration shows an example of a molding compound 105 covering a first conductive plate 109 to improve electrical insulation performance and prevent edge creepage. In other embodiments of this application, the molding compound 105 may also be entirely located between the substrate 106 and the first conductive plate 109; this application does not impose specific limitations on the embodiments.
[0081] Continue reading Figure 6 The power module 10 also includes a second conductive post 110, which is disposed between the second conductive region 1063 and the first conductive plate 109, and connects the second conductive region 1063 and the first conductive plate 109. The first power chip 107 can be connected to the first conductive plate 109 through the first conductive post 108, and the first conductive plate 109 can be connected to the second conductive region 1063 through the second conductive post 110. This achieves the connection between the first power chip 107 and the second conductive region 1063.
[0082] Continue reading Figure 6 The first conductive plate 109 is arranged parallel to the substrate 106. Compared to some related technologies that use copper wire bonding or other methods for inter-chip conductivity, in this application, both the first conductive post 108 and the second conductive post 110 can support the first conductive plate 109. This ensures that the substrate 106 and the first conductive plate 109 are arranged parallel to each other. In the packaged power module 10, the first conductive plate 109 can also provide support, improving the anti-warping effect of the power module 10.
[0083] See Figure 7 , Figure 7 for Figure 3 The diagram shows another structural representation of the power module 10 along direction A after removing the molding compound 105, first terminal 101, second terminal 102, third terminal 103, and pins 104. The first conductive plate 109 includes a first portion 1092 and a second portion 1093. The first portion 1092 is connected to the first conductive post 108, and the second portion 1093 is bent towards the substrate 106 and connected to the second conductive region 1063. The first power chip 107 can be electrically connected to the first portion 1092 of the first conductive plate 109 via the first conductive post 108, and the second portion 1093 of the first conductive plate 109 can be electrically connected to the second conductive region 1063, thereby achieving electrical connection between the first power chip 107 and the second conductive region 1063. The second portion 1093 of the first conductive plate 109 is bent directly downwards, achieving electrical connection with the second conductive region 1063 without the need for other structures, thus saving material.
[0084] See Figure 8 , Figure 8 for Figure 7 In the top view of the power module 10 shown, along the second direction X, the width w1 of the portion where the first part 1092 connects to the first conductive post 108 is smaller than the width w2 of the first conductive post 108. The second direction X is perpendicular to the thickness direction Z of the power module 10. The smaller connection area between the first part 1092 of the first conductive plate 109 and the first conductive post 108 results in a smaller tensile force on the first conductive post 108. This reduces the stress on the surface of the first power chip 107, lowering the risk of cracking at the connection between the first power chip 107 and the first conductive post 108.
[0085] Continue reading Figure 8 A first opening 1091 is provided on the first conductive plate 109. The first opening 1091 can be provided near the connection between the first conductive plate 109 and the first conductive post 108.
[0086] See Figure 9 , Figure 9 for Figure 3 The power module 10 shown is another structural schematic diagram along direction A after removing the molding compound 105, the first terminal 101, the second terminal 102, the third terminal 103, and the pins 104. The material of the first conductive plate includes metallic materials. For example, the material of the first conductive plate 109 is copper, copper alloy, etc. The first conductive plate 109 using this material has low cost and is easy to open the first opening 1091 (e.g., ...). Figure 5 (As shown).
[0087] Continue reading Figure 9A welding layer 111 is provided between the first conductive post 108 and the first conductive plate 109. The welding layer 111 is used to connect the first conductive post 108 and the first conductive plate 109. The welding layer 111 can be formed by a reflow soldering process to achieve the connection and conduction between the first conductive post 108 and the first conductive plate 109.
[0088] Or, see Figure 4 The first conductive post 108 is in contact with and fixed to the first conductive plate 109. The first conductive post 108 and the first conductive plate 109 can be directly welded and fixed by laser welding or ultrasonic welding to achieve connection and conduction between the first conductive post 108 and the first conductive plate 109.
[0089] See Figure 10 The first power chip has a gate S. The gate S of the first power chip 107 is exposed on the first conductive post 108. This is to prevent the first conductive post 108 from blocking the gate S of the first power chip 107, so that the gate S of the first power chip 107 cannot be electrically connected to other components (such as a drive module).
[0090] Continue reading Figure 10 The material of the first conductive post includes pure metal, alloy, or composite material. For example, the material of the first conductive post 108 can be pure metal, such as copper. The first conductive post 108 using this material has low cost, high heat capacity, and high thermal conductivity, which can effectively absorb the heat dissipated by the first power chip 107, resist junction temperature fluctuations, and reduce the cost of the power module 10.
[0091] Alternatively, the first conductive post 108 can be made of an alloy, such as a molybdenum-copper (MoCu) alloy. The first conductive post 108 can also be made of a composite material, such as aluminum silicon carbide (AlSiC) or copper diamond. Using this material results in a low coefficient of thermal expansion for the first conductive post 108, preventing it from compressing and damaging the first power chip 107 due to expansion.
[0092] Alternatively, the first conductive post 108 can also be a composite structure, for example, see [reference needed]. Figure 11 , Figure 11 for Figure 3 The power module 10 shown is illustrated in another structural diagram along direction A after removing the molding compound 105, the first terminal 101, the second terminal 102, the third terminal 103, and the pins 104. A portion of the first conductive post 108 is made of copper, and a portion is made of a MoCu alloy, etc. This application does not impose specific limitations.
[0093] Continue reading Figure 11The first conductive post comprises a first copper layer 1081, a molybdenum-copper alloy layer 1082, and a second copper layer 1083 connected in sequence. The first copper layer 1081 is connected to the first power chip 107, and the second copper layer 1083 is connected to the first conductive plate 109. Copper has a high heat capacity and high thermal conductivity, allowing the first copper layer 1081, connected to the first power chip 107, to quickly absorb the heat released by the first power chip 107. The second copper layer 1083, connected to the first conductive plate 109, can also transfer heat to the first conductive plate 109 for heat dissipation. The molybdenum-copper alloy has a low coefficient of thermal expansion, and the molybdenum-copper alloy layer 1082, located between the first copper layer 1081 and the second copper layer 1083, can reduce the overall thermal expansion of the first conductive post 108. This prevents the expansion of the first conductive post 108 from squeezing and damaging the first power chip 107.
[0094] See Figure 12 The power module also includes a second power chip 112 and a third conductive post 113. The second power chip 112 is disposed in the second conductive region 1063. The third conductive post 113 is disposed on the side of the second power chip 112 opposite to the second conductive region 1063, and is connected to and conducts through the second power chip 112. Under the condition of instantaneous high power consumption of the second power chip 112, the third conductive post 113 can provide heat absorption and energy storage effect, reducing the maximum transient junction temperature of the second power chip. This ensures that the junction temperature fluctuation of the second power chip is small under large power consumption, so that while meeting the requirement of reducing the failure rate of the power module 10, the second power chip does not need to be excessively dated due to the transient high junction temperature, further increasing the output power that the power module 10 can generate.
[0095] Continue reading Figure 12The first terminal 101 of the power module is electrically connected to the first conductive region 1062. The second terminal 102 is electrically connected to the third conductive post 113. The third terminal 103 is electrically connected to the second conductive region 1063. When the power module 10 is working, the first power chip 107 and the second power chip 112 can be in an alternating conduction state. The battery is connected through the first terminal 101 and the second terminal 102. After the power module 10 converts DC to AC, it is output through the third terminal 103. Alternatively, by inputting AC current to the third terminal 103, the power module 10 converts AC to DC, and then outputs DC current through the first terminal 101 and the second terminal 102. Along a direction parallel to the side surface of the substrate 106 facing the first power chip 107 (e.g., the width direction Y of the power module 10), the first terminal 101 and the second terminal 102 are located on the same side of the substrate 106. Along a direction perpendicular to this direction and parallel to the side surface of the substrate 106 facing the first power chip 107 (i.e., the length direction X of the power module 10), the dimensions of the first terminal 101 and the second terminal 102 overlap, which can optimize the overall layout of the power module 10 and help reduce the size of the power module 10.
[0096] Continue reading Figure 12 The groove 1061 further divides the substrate 106 into a third conductive region 1064, which is electrically connected to the second terminal 102. The power module 10 also includes a second conductive plate 114 and a fourth conductive post 115. The second conductive plate 114 is disposed on the side of the third conductive post 113 facing away from the second power chip 112, and is connected to and conducts through the third conductive post 113. The fourth conductive post 115 is disposed between the second conductive plate 114 and the third conductive region 1064. The fourth conductive post 115 connects and conducts through the second conductive plate 114 and the third conductive region 1064. Both the third conductive post 113 and the fourth conductive post 115 can support the second conductive plate 114. The substrate 106 and the second conductive plate 114 are stacked, and the second conductive plate 114 also provides support, further improving the anti-warping effect of the power module 10.
[0097] Continue reading Figure 12 The second conductive plate has a second opening 1141. When the second conductive plate 114 undergoes thermal expansion and contraction, the second opening 1141 can reduce the degree of deformation of the second conductive plate 114, preventing excessive deformation of the second conductive plate 114 in the direction parallel to the substrate 106 towards the surface of the second power chip 112 (direction in the XY plane). This prevents excessive deformation from causing a force on the third conductive post 113 in the direction parallel to the substrate 106 towards the surface of the second power chip 112, thus avoiding a pulling effect on the third conductive post 113. This prevents cracking at the connection between the third conductive post 113 and the second power chip 112.
[0098] Or, see Figure 8 A portion of the second conductive plate 114 is connected to the third conductive post 113, and another portion of the second conductive plate 114 is bent toward the substrate 106 and connected to the third conductive region 1064. The second power chip 112 can be electrically connected to a portion of the second conductive plate 114 through the third conductive post 113, and the other portion of the second conductive plate 114 can be electrically connected to the third conductive region 1064, thereby achieving electrical connection between the second power chip 112 and the third conductive region 1064. The other portion of the second conductive plate 114 is bent directly downwards, achieving electrical connection with the third conductive region 1064 without the need for other structures, thus saving materials.
[0099] The width w3 of the second conductive plate 114 is smaller than the width w4 of the third conductive post 113. This reduces the width of the second conductive plate 114 and the connection area of the third conductive post 113, thereby reducing the tensile force on the third conductive post 113. This also reduces the stress on the surface of the second power chip 112, lowering the risk of cracking at the connection between the second power chip 112 and the third conductive post 113.
[0100] Continue reading Figure 12 The material of the second conductive plate 114 includes metallic materials. For example, the material of the second conductive plate 114 is copper, copper alloy, etc. The second conductive plate 114 using this material is low in cost and easy to form the first opening 1091.
[0101] A welding layer (not shown in the figure) may also be provided between the third conductive post 113 and the second conductive plate 114. The welding layer may be formed by reflow soldering process to achieve connection and conduction between the third conductive post 113 and the second conductive plate 114.
[0102] Alternatively, the third conductive post 113 can be in contact with and fixed to the second conductive plate 114. The third conductive post 113 and the second conductive plate 114 can be directly welded and fixed by laser welding or ultrasonic welding to achieve connection and conduction between the third conductive post 113 and the second conductive plate 114.
[0103] Continue reading Figure 12 The second power chip 112 also has a gate. The gate of the second power chip 112 is exposed to the third conductive post 113. This is to prevent the third conductive post 113 from blocking the gate of the second power chip 112, thus preventing the gate of the second power chip 112 from being electrically connected to other components (such as the drive module).
[0104] The material of the third conductive post 113 can be a pure metal, an alloy, or a composite material. For example, the material of the third conductive post 113 can be a pure metal, such as copper. The third conductive post 113 using this material has low cost, high heat capacity, and high thermal conductivity, which can effectively absorb the heat dissipated by the second power chip 112, resist junction temperature fluctuations, and reduce the cost of the power module 10.
[0105] Alternatively, the material of the third conductive post 113 can also be an alloy, such as a molybdenum-copper (MoCu) alloy. The material of the third conductive post 113 can also be a composite material, such as aluminum silicon carbide (AlSiC) or copper diamond. The third conductive post 113 made of such materials has a low coefficient of thermal expansion, preventing the expansion of the third conductive post 113 from squeezing and damaging the second power chip 112.
[0106] Alternatively, the third conductive post 113 can also be a composite structure, for example, see [reference needed]. Figure 11 The third conductive post 113 is partly made of copper and partly of MoCu alloy, etc. This application does not make specific limitations.
[0107] Exemplary examples show that in any of the above embodiments, the first power chip 107 includes at least one of a metal-oxide-semiconductor field-effect transistor (MOS), a fast recovery diode (FRD), and an insulated-gate bipolar transistor (IGBT). The second power chip 112 includes at least one of a MOS, a fast recovery diode, and an IGBT. The embodiments in this application are not specifically limited.
[0108] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A power module, characterized in that, include: Substrate, first power chip, first conductive pillar, and first conductive plate; The substrate has a groove that divides the substrate into a first conductive region and a second conductive region. The first power chip is disposed on the first conductive area; The first conductive post is disposed on the side of the first power chip that is away from the substrate; The first conductive plate is disposed on the side of the first conductive post away from the substrate, and the first conductive plate is used to connect the first conductive post and the second conductive area; The first conductive plate has a first opening along the thickness direction of the power module.
2. The power module according to claim 1, characterized in that, The projection of the first opening in the thickness direction of the power module does not overlap with the projection of the first conductive post in the thickness direction of the power module.
3. The power module according to claim 1 or 2, characterized in that, Along the first direction, the distance between the first opening and the first conductive post is less than a set threshold, and the first direction is perpendicular to the thickness direction of the power module.
4. The power module according to any one of claims 1-3, characterized in that, Around the periphery of the connection between the first conductive plate and the first conductive post, the first conductive plate is provided with a plurality of the first openings.
5. The power module according to any one of claims 1-4, characterized in that, Along the thickness direction of the power module, the thickness of the first conductive post is greater than the thickness of the first conductive plate.
6. The power module according to any one of claims 1-5, characterized in that, The power module further includes a molding compound that encapsulates the first power chip, the first conductive pillar, and the first conductive plate, with a portion of the molding compound disposed within the first opening.
7. The power module according to any one of claims 1-6, characterized in that, The power module further includes a second conductive post, which is disposed between the second conductive area and the first conductive plate.
8. The power module according to any one of claims 1-7, characterized in that, The first conductive plate is arranged parallel to the substrate.
9. The power module according to any one of claims 1-6, characterized in that, The first conductive plate includes a first part and a second part. The first part is connected to the first conductive post, and the second part is bent toward the substrate and connected to the second conductive area.
10. The power module according to claim 9, characterized in that, Along the second direction, the width of the portion of the first part connected to the first conductive post is smaller than the width of the first conductive post, and the second direction is perpendicular to the thickness direction of the power module.
11. The power module according to any one of claims 1-10, characterized in that, The first power chip has a gate, and the gate of the first power chip is exposed on the first conductive post.
12. The power module according to any one of claims 1-11, characterized in that, The material of the first conductive post includes pure metal, alloy or composite material.
13. The power module according to any one of claims 1-12, characterized in that, The first conductive post includes a first copper layer, a molybdenum-copper alloy layer, and a second copper layer connected in sequence. The first copper layer is connected to the first power chip, and the second copper layer is connected to the first conductive plate.
14. A power converter, characterized in that, The device includes a heat sink and at least one power module as described in any one of claims 1-13, wherein the heat sink is disposed on the side of the substrate opposite to the first conductive plate, and the power converter is used for AC / DC conversion.