Power substrate and power module

Abstract

The utility model discloses a kind of power substrate and power module, applied to power device technical field, comprising: heat dissipation structure;Heat dissipation structure includes heat dissipation metal plate, heat dissipation metal plate one side surface is provided with recess;Fixed in the insulating layer of recess bottom surface;Setting in the electrical connection layer of insulating layer far from heat dissipation metal plate one side surface;The distance of the top surface of electrical connection layer and recess bottom surface is not less than the depth of recess, and the side wall of electrical connection layer and recess is mutually isolated.By etching recess in heat dissipation metal plate, and the mode of directly setting insulating layer in groove, the setting of traditional metal connecting layer can be reduced and the distance of insulating layer to heat dissipation metal plate bottom surface is reduced, so as to reduce heat dissipation path, increase heat dissipation efficiency.The distance of the top surface of simultaneously setting electrical connection layer and recess bottom surface is not less than the depth of recess, so that the position where power chip is located can be higher than heat dissipation metal plate, guarantee the availability of power module, conducive to the reduction of power module volume.

Description

Technical Field

[0001] This utility model relates to the field of power device technology, and in particular to a power substrate and a power module. Background Technology

[0002] A power semiconductor module is a device capable of high-frequency, high-voltage, and high-current output. It consists of multiple power chips arranged in a specific electrical topology and packaged into an integrated module, making it readily applicable in industrial, new energy, and electronic fields. The power substrate, as a key component of the power module, plays a crucial role in industries such as new energy vehicles. With continuous technological advancements and market development, power substrates are trending towards higher performance, lower cost, smaller size, and lighter weight.

[0003] In existing power module packaging structures, the power substrate plays a crucial role, providing electrical interconnection and insulation, corrosion protection, mechanical support, and heat dissipation channels for semiconductor chips. Currently, commonly used power substrates can be mainly classified into polymer substrates, insulating metal substrates, and ceramic substrates based on their materials. Due to the high voltage, high power, and high heat generation characteristics of power semiconductor modules, the use of polymer substrates and insulating metal substrates is greatly limited, while ceramic substrates are the most widely used due to their high thermal conductivity, good heat resistance, high insulation, and high strength.

[0004] Currently, ceramic substrates typically consist of an electrical connection layer, a ceramic layer, and a metal connection layer from top to bottom. The metal connection layer connects to a heat sink, and a heat dissipation structure is then located on the outside of the heat sink. Therefore, the heat dissipation path from the power chip typically includes a solder layer → electrical connection layer → ceramic layer → metal connection layer → solder layer → heat sink → heat dissipation structure. This long heat dissipation path results in high thermal resistance, which, especially in new energy motor drives, often leads to power module failure and serious safety accidents due to poor heat dissipation performance. Furthermore, the heat dissipation efficiency is low. Therefore, providing a power substrate with a shorter heat dissipation path is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to provide a power substrate with high heat dissipation performance; another purpose of this invention is to provide a power module with high heat dissipation performance.

[0006] To solve the above-mentioned technical problems, this utility model provides a power substrate, comprising:

[0007] Heat dissipation structure; the heat dissipation structure includes a heat dissipation metal plate, and a groove is provided on one side surface of the heat dissipation metal plate;

[0008] An insulating layer fixed to the bottom surface of the groove;

[0009] An electrical connection layer is disposed on the surface of the insulating layer away from the heat dissipation metal plate; the distance between the top surface of the electrical connection layer and the bottom surface of the groove is not less than the depth of the groove, and the electrical connection layer is isolated from the sidewall of the groove;

[0010] The heat dissipation metal plate is provided with a connection structure that connects to the outer casing.

[0011] By etching grooves into the heat sink and directly placing an insulating layer within the grooves, the number of traditional metal connection layers can be reduced, as can the distance between the insulating layer and the bottom surface of the heat sink. This shortens the heat dissipation path and increases heat dissipation efficiency. Simultaneously, ensuring the distance between the top surface of the electrical connection layer and the bottom surface of the groove is no less than the groove depth allows the power chip to be positioned higher than the heat sink. This increases the vertical isolation between the power chip and the heat sink, further improving the heat dissipation performance of the power module while reducing its size.

[0012] Optionally, the top surface of the electrical connection layer is flush with the top surface of the groove sidewall.

[0013] Optionally, a first gap exists between the side of the insulating layer and the sidewall of the groove; and / or, a second gap exists between the edge of the electrical connection layer and the edge of the insulating layer.

[0014] Optionally, the heat dissipation structure may further include a protruding structure located on the surface of the heat dissipation metal plate away from the insulating layer.

[0015] Optionally, the protrusion structure includes scattering pillars extending along the side away from the insulating layer, and the heat dissipation pillars are distributed in an array.

[0016] Optionally, the insulating layer includes a host layer with the same material as the substrate in the power chip to be bonded, and the host layer has an insulating film layer disposed on at least the surface on which the electrical connection layer is disposed, and the electrical connection layer is isolated from the host layer through the insulating film layer.

[0017] The thermal expansion coefficient of the insulating layer provided in this application is highly compatible with that of the power chip. Whether it is vacuum high-temperature reflow soldering in the production process or the high-temperature working environment of the module, the deformation of the insulating layer is consistent with that of the power chip, which reduces the risk of power chip failure and improves device reliability.

[0018] Optionally, the insulating layer comprises a silicon wafer, the host layer comprises a silicon wafer, and the insulating film layer comprises an oxide layer.

[0019] This application selects silicon material, the same as the power chip, for the insulating layer. This facilitates synchronous electrical consistency and solves the technical problem of power chip failure caused by deformation due to thermal stress during the power chip soldering process. The insulating layer in this solution uses the same silicon-based material as the power chip, with the same or similar coefficient of thermal expansion. At the same temperature, the deformation is identical with minimal error, avoiding power chip failure caused by deformation differences between the insulating layer and the insulating layer during soldering. Furthermore, the power module in this solution uses a silicon wafer as the substrate, resulting in low material cost and high thermal conductivity, which helps to reduce the size of the power chip and the overall device volume.

[0020] Optionally, when fixing the power chip at the first temperature, the electrical connection layer is a fluid metal layer.

[0021] This application reduces the copper foil layer, significantly reducing the three-layer thermal resistance, resulting in a lightweight structure. The reduction in metal layers also contributes to lower cost and higher reliability. While reducing material usage, the lateral heat dissipation capacity of the power module is improved by 10-30 times, subtly enhancing heat dissipation performance while maintaining reliability. Furthermore, the use of liquid metal to form the electrical metal layer further avoids power chip failures caused by inconsistent thermal expansion coefficients, improving the production yield of the power module and reducing cost losses.

[0022] Compared with the existing thermal stress compensation structure of heat dissipation base plate, this application does not require arc design, has a thin weld layer, good welding quality, low residual stress, low risk of leakage, and high reliability.

[0023] Optionally, the heat dissipation metal plate can be any of the following:

[0024] Aluminum heat sink, aluminum alloy heat sink, copper heat sink, copper-aluminum alloy heat sink.

[0025] This application also provides a power module, including a power chip and a power substrate as described in any of the above claims, wherein the power chip is fixedly connected to the electrical connection layer.

[0026] This power module also has the aforementioned beneficial effects, which will not be elaborated upon here. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a schematic diagram of the structure of a power substrate provided in an embodiment of the present utility model;

[0029] Figure 2 This is a schematic diagram of the structure of a specific power substrate provided in an embodiment of the present utility model;

[0030] Figure 3 An exploded view of a power module provided for an embodiment of this utility model;

[0031] Figure 4 This is a schematic diagram of the structure of a power module provided in an embodiment of the present utility model;

[0032] Figure 5 This is a top view of a power module fabricated in this embodiment;

[0033] Figure 6 for Figure 5 A sectional view along line AA.

[0034] In the diagram: 1. Heat dissipation metal plate, 2. Insulating layer, 3. Electrical connection layer, 4. Raised structure, 5. Power chip, 6. Bonding wire, 7. Power pin, 8. Housing, 9. Encapsulation colloid, 10. Cover plate. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0036] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] The heat dissipation base plate structure for existing power semiconductor modules is usually made of solid metal (copper or silicon carbide aluminum AlSiC) plates, with a thickness of 3mm to 8mm. These are typically divided into flat-bottom indirect heat dissipation structures and integrated pin-fin direct cooling structures. The substrate of a power module, based on its application requirements, needs to possess high thermal conductivity (good thermal conductivity to effectively dissipate the heat generated by the power module), a reasonable coefficient of thermal expansion (similar to the chip's coefficient of thermal expansion to avoid thermal stress at the interface under high temperatures, which could lead to interface breakage or damage), high strength (sufficient mechanical strength to operate normally under high vibration), long lifespan (meeting the vehicle's design lifespan requirements, typically 15 years or more, with zero failures), small size, and low cost (avoiding excessively large assembly volume and reducing manufacturing costs). The ceramic substrate materials used in existing power modules, such as DBC or AMB ceramic substrates, are generally ceramic sheets made of Al2O3, AlN, Si3N4, or zirconium-doped Al2O3. Although these materials meet the needs of most application scenarios, they cannot simultaneously possess the advantages of high thermal conductivity, reasonable thermal expansion, low cost, and high strength. Therefore, they require adaptive selection for different application scenarios, resulting in low compatibility.

[0038] Meanwhile, the existing standard power module's overall structure consists of a chip, a DBC (Direct Bonded Copper) ceramic substrate, and a heat sink metal plate. The power chip transmits electrical functions through bonding wires or copper strips. The power chip, DBC ceramic substrate, and heat sink metal plate are connected by vacuum reflow soldering to achieve thermal conductivity, insulation, and corresponding electrical performance. When the power chip is working, it generates a large amount of heat. Most of this heat is transferred to the heat sink metal plate through the DBC ceramic substrate and dissipated through the flow of coolant. This packaging method has at least the following technical problems:

[0039] 1. Because this classic packaging module needs to be manufactured in a vacuum and high-temperature environment, the heat dissipation metal plate bends towards the back due to its smaller coefficient of thermal expansion than the DBC ceramic substrate (see "CN103794571A"). This bending leads to solder fatigue damage, and the DBC ceramic substrate and heat dissipation base plate are prone to soldering voids, which directly affect the heat dissipation of the overall system. At the same time, during soldering, the DBC ceramic substrate and the power chip will also deform due to the thermal stress generated by the high temperature, which can easily cause the power chip to over-deform and fail. Overall, the reliability is low, the production process requires strict settings, the fixture design is complex, and the production process is complicated and cumbersome.

[0040] Specifically, the power chip, ceramic substrate, and metal base plate are connected by soldering. Since the thermal expansion coefficients of each layer are different, temperature changes during the soldering and operation processes can cause the base plate to bend and deform, generating stress on the solder surface. Appropriate installation pressure is required between the base plate and the heat sink or cooling water tank to ensure optimal thermal contact, reduce interfacial thermal resistance, or seal the cooling water. This requires the finished module base plate (heat dissipation metal plate) to have a certain curvature. This curvature is opposite to the direction of bending deformation caused by soldering; therefore, the base plate cannot be flat before soldering and must have a pre-existing curvature for compensation and suppression. High precision is required for the pre-curvature, making processing difficult. Excessive curvature results in a thick solder layer, easily causing voids and high installation stress; insufficient curvature leads to high interfacial thermal resistance or poor sealing and leakage.

[0041] 2. Due to the differences in the thermal expansion coefficients of various materials in the existing power module substrate, the current production process is relatively complex and has a high defect rate, which further leads to high production costs and is not conducive to the industrial application of power modules.

[0042] 3. In the prior art, the ceramic substrate typically includes an electrical connection layer, a ceramic layer and a metal connection layer from top to bottom. The metal connection layer is used to connect with the heat dissipation metal plate, and a heat dissipation structure is provided on the outside of the heat dissipation metal plate. At this time, the heat dissipation path from the power chip usually includes a solder layer → electrical connection layer → ceramic layer → metal connection layer → solder layer → heat dissipation metal plate → heat dissipation structure. This heat dissipation path is long and the heat dissipation efficiency is low.

[0043] Based on this, the present invention provides a power substrate comprising: a heat dissipation structure; the heat dissipation structure comprising a heat dissipation metal plate, wherein a groove is provided on one side surface of the heat dissipation metal plate; an insulating layer fixed to the bottom surface of the groove; an electrical connection layer disposed on the side surface of the insulating layer away from the heat dissipation metal plate; the distance between the top surface of the electrical connection layer and the bottom surface of the groove is not less than the depth of the groove, and the electrical connection layer is isolated from the sidewall of the groove; the heat dissipation metal plate is provided with a connection structure for connecting to the outer shell.

[0044] By etching grooves into the heat sink and directly placing an insulating layer within the grooves, the number of traditional metal connection layers can be reduced, as can the distance between the insulating layer and the bottom surface of the heat sink. This shortens the heat dissipation path and increases heat dissipation efficiency. Simultaneously, ensuring that the distance between the top surface of the electrical connection layer and the bottom surface of the groove is no less than the depth of the groove allows the power chip to be positioned higher than the heat sink. This increases the vertical isolation between the power chip and the heat sink, ensuring the usability of the power module and contributing to a reduction in its size.

[0045] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a power substrate provided in an embodiment of the present invention.

[0048] See Figure 1 In this embodiment, the power substrate includes a heat dissipation structure; the heat dissipation structure includes a heat dissipation metal plate 1, a groove is provided on one side surface of the heat dissipation metal plate 1; an insulating layer 2 is fixed to the bottom surface of the groove; an electrical connection layer 3 is disposed on the side surface of the insulating layer 2 away from the heat dissipation metal plate 1; the distance between the top surface of the electrical connection layer 3 and the bottom surface of the groove is not less than the depth of the groove, and the electrical connection layer 3 is isolated from the sidewall of the groove; the heat dissipation metal plate 1 is provided with a connection structure for connecting to the outer casing 8.

[0049] The aforementioned heat dissipation structure is the primary structure for heat dissipation in the power module. This structure must include at least one heat dissipation metal plate 1. The heat dissipation metal plate 1 is typically plate-shaped, and its thickness is usually not excessive. Generally, the heat dissipation metal plate 1 is a plate-shaped material made of metal, such as aluminum or copper, which typically has high thermal conductivity and a certain structural strength. In this embodiment, a groove is specifically etched inwards on one side surface of the heat dissipation metal plate 1, which obviously further reduces the thickness of the heat dissipation metal plate 1 at the groove.

[0050] In this embodiment, an insulating layer 2 needs to be fixed to the bottom surface of the aforementioned groove. The insulating layer 2 is the main structure of the power substrate, and it not only needs to provide certain mechanical properties but also good heat dissipation performance and good insulation. The insulating layer 2 needs to be directly fixed to the bottom surface of the groove. In this embodiment, the insulating layer 2 can be soldered to the bottom surface of the groove using solder. At this time, at most one layer of solder is provided between the insulating layer 2 and the heat dissipation metal plate 1, without any other structures such as metal connection layers.

[0051] In this embodiment, an electrical connection layer 3 is provided on the surface of the insulating layer 2 away from the heat dissipation metal plate 1. The electrical connection layer 3 is mainly used for welding the power substrate and the power chip 5. Therefore, the electrical connection layer 3 needs to be isolated from the heat dissipation metal plate 1. It needs to avoid direct contact between the electrical connection layer 3 and the side wall of the groove. That is, the electrical connection layer 3 needs to be isolated from the side wall of the groove to avoid electrical connection between the electrical connection layer 3 and the heat dissipation metal plate 1.

[0052] In this embodiment, to reduce the heat dissipation path of the power chip 5, the depth of the groove in the heat dissipation metal plate 1 can be further increased. Simultaneously, to ensure the isolation between the power chip 5 and the heat dissipation metal plate 1, the top surface of the electrical connection layer 3 can be flush with the top surface of the groove sidewall. At this point, the heat dissipation path from the power chip 5 to the exposed surface of the heat dissipation metal plate 1 is minimized, while simultaneously ensuring the isolation between the power chip 5 and the heat dissipation metal plate 1.

[0053] Specifically, in this embodiment, a first gap exists between the side of the insulating layer 2 and the sidewall of the groove; and / or, a second gap exists between the edge of the electrical connection layer 3 and the edge of the insulating layer 2. In this embodiment, the insulating layer 2 may not be disposed along the inner sidewall of the groove, but rather a first gap exists between the insulating layer 2 and the sidewall of the groove, thereby increasing the lateral distance between the electrical connection layer 3 and the heat dissipation metal plate 1. Furthermore, in this embodiment, a second gap may be provided between the edge of the electrical connection layer 3 and the edge of the insulating layer 2. In this case, the lateral distance between the electrical connection layer 3 and the heat dissipation metal plate 1 is the sum of the first gap and the second gap, further increasing the lateral isolation between the electrical connection layer 3 and the heat dissipation metal plate 1. The specific values ​​of the first gap and the second gap can be set according to actual conditions and are not specifically limited here. In this embodiment, multiple insulating layers 2 can be disposed within the groove of a heat dissipation structure, and their number is not specifically limited in this embodiment.

[0054] Specifically, in this embodiment, the insulating layer 2 includes a main layer made of the same material as the substrate of the power chip 5 to be bonded, and an insulating film layer is disposed on the surface of the main layer. That is, in this embodiment, the insulating layer 2 specifically includes a main layer and an insulating film layer covering the surface of the main layer. The main layer is the main structure of the insulating layer 2, so the main layer can be a flat structure, that is, the surface of the main layer is flat and has no curvature. In this embodiment, the material of the main layer needs to be the same as the substrate material of the power chip 5 to be bonded, so that the thermal expansion coefficient of the insulating layer 2 is approximately the same as that of the power chip 5. This setting can ensure that the insulating layer 2 will not bend in a high-temperature environment due to the large difference in thermal expansion coefficients compared with the power chip 5, and ensure that no gap will be generated between the power substrate and the power chip 5 due to the difference in thermal expansion coefficients in a high-temperature environment. Therefore, the main layer can be set as a flat structure, and the bottom surface of the groove can be simply set as a plane. At this time, the fabrication of the power substrate is relatively simple.

[0055] Since the material of the aforementioned main layer is the same as that of the substrate in power chip 5, it is typically a semiconductor material. This material usually has excellent thermal conductivity, but in order to ensure its insulation, in this embodiment, an insulating film layer needs to be formed on the surface of the main layer. This insulating film layer is usually attached to the surface of the main layer in the form of a film layer. It usually does not excessively affect the thermal expansion coefficient of the main layer, but it can greatly improve its insulation, making the semiconductor material main layer suitable for power substrates.

[0056] It should be noted that the aforementioned insulating film layer must be at least located in the area of ​​the main body layer corresponding to the area where the electrical connection layer 3 is located. That is, the insulating film layer isolates the electrical connection layer 3 from the main body layer. The electrical connection layer 3 is used to solder with the power chip 5. In this case, the electrical connection layer 3 is electrically isolated from the main body layer in the thickness direction through the insulating film layer, and in the horizontal direction, the electrical connection layer 3 is physically separated from the heat sink metal plate 1. Therefore, this structure ensures that the electrical connection layer 3 is electrically insulated from the heat sink metal plate 1, preventing the heat sink metal plate 1 from interfering with the circuitry of the power chip 5. In addition to being located in the area corresponding to the electrical connection layer 3, the aforementioned insulating film layer can further cover all surfaces of the main body layer, thereby ensuring that the electrical connection layer 3 is insulated from the heat sink metal plate 1. In one feasible example, the aforementioned insulating film layer can at least cover the surface of the main body layer away from the heat sink metal plate 1 to ensure that the electrical connection layer 3 is insulated from the heat sink metal plate 1. In another feasible example, to facilitate the installation of the insulating film layer, the insulating film layer can cover the entire surface of the main body layer.

[0057] Specifically, in this embodiment, the main body layer includes a silicon wafer, and the insulating film layer includes an oxide layer. That is, in this embodiment, a silicon wafer can be used as the main body layer, and silicon is also the material used in the substrate of conventional power chip 5. The silicon wafer can be either a monocrystalline silicon wafer or a polycrystalline silicon wafer; no specific limitation is made here. Choosing silicon material of the same type as power chip 5 for the main body layer is beneficial for maintaining consistent thermal expansion coefficients, which can solve the technical problem of deformation caused by thermal stress during the welding process of power chip 5, leading to chip failure. In this embodiment, the insulating layer 2 uses the same silicon-based material as power chip 5, with the same or similar thermal expansion coefficients. At the same temperature, the deformation is the same with minimal error, avoiding the failure or damage of power chip 5 caused by deformation differences due to differences in thermal expansion coefficients between power chip 5 and the power substrate during the welding process.

[0058] The aforementioned oxide layer needs to specifically serve as an insulating film layer to ensure electrical isolation between the electrical connection layer 3 and the heat dissipation metal plate 1. Typically, the oxide layer can cover at least the surface of the silicon wafer furthest from the heat dissipation metal plate 1. Of course, the oxide layer can further cover the entire surface of the silicon wafer to increase its insulation. It should be noted that this oxide layer needs to be a dense oxide layer, rather than an oxide layer formed by natural oxidation, to enhance its insulating properties.

[0059] Furthermore, in this embodiment, the heat dissipation metal plate 1 is provided with a connection structure that connects to the outer casing 8. This connection structure is used to fix the power substrate to the outer casing 8 when packaging the power module. The specific details of this connection structure can be set according to actual conditions and are not specifically limited here. Specifically, in this embodiment, the non-recessed area of ​​the heat dissipation metal plate 1 can be provided with mounting holes extending along the thickness direction. The aforementioned mounting holes serve as a connection structure and can be interconnected with the outer casing 8 by screws. It should be noted that the mounting holes are located in the non-recessed area of ​​the heat dissipation metal plate 1, and specifically extend along the thickness direction without penetrating the insulating layer 2. Therefore, the setting of the mounting holes can avoid affecting the structure of the insulating layer 2, that is, avoid drilling holes in semiconductor materials such as silicon to ensure that the insulating layer 2 has sufficient structural strength. In addition to setting mounting holes as a connection structure, other structures can also be set as connection structures, and are not specifically limited here.

[0060] The insulating layer provided in this application has a high coefficient of thermal expansion that matches the power chip. Whether in the vacuum high-temperature reflow soldering process or the high-temperature operating environment of the module, the deformation of the insulating layer is consistent with the deformation of the power chip, reducing the risk of power chip failure and improving device reliability. Furthermore, the power module in this solution uses a silicon wafer as a substrate, resulting in low material cost and high thermal conductivity, which is beneficial for reducing the size of the power chip and the overall device volume.

[0061] The insulating layer 2 of this application is made of silicon material, which is the same material as the power chip 5. This is beneficial for synchronous electrical consistency and can solve the technical problem of deformation caused by thermal stress during the welding process of the power chip 5, which leads to the failure of the power chip 5. The insulating layer 2 of this solution uses silicon-based material, which is the same as the power chip 5. The coefficient of thermal expansion is the same or similar. At the same temperature, the deformation is the same and the error is small. This avoids the failure and damage of the power chip 5 caused by the difference in deformation due to the different coefficient of thermal expansion between the insulating layer 2 and the power chip 5 during the welding process.

[0062] The specific details of the power substrate provided in this application will be described in detail in the following embodiments.

[0063] Example 2

[0064] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a specific power substrate provided in an embodiment of the present invention.

[0065] Unlike the embodiments described above, this embodiment further defines the structure of the power substrate based on the above embodiments. The remaining details have been described in detail in the above embodiments and will not be repeated here.

[0066] See Figure 2 In this embodiment, the heat dissipation structure further includes a protruding structure 4 located on the surface of the heat dissipation metal plate 1 away from the insulating layer 2. This protruding structure 4 needs to be fixedly connected to the heat dissipation metal plate 1, allowing heat to be transferred from the heat dissipation metal plate 1 to the protruding structure 4 for heat dissipation. The protruding structure 4 increases the heat dissipation area relative to the heat dissipation metal plate 1, and can be further combined with heat dissipation components such as water cooling to improve the heat dissipation performance of the power substrate. It should be noted that the protruding structure 4 and the heat dissipation metal plate 1 are suitable for higher heat dissipation requirements. When the heat dissipation requirement is low, only the heat dissipation metal plate 1 can be provided without the aforementioned protruding structure 4, making it suitable for low-power applications. This embodiment does not require a metal connection layer; that is, in this embodiment, the power substrate and the heat dissipation structure can be combined by directly setting the insulating layer 2 within the groove of the heat dissipation metal plate 1. The heat conduction path is very short, which helps to improve the heat dissipation performance of the power substrate.

[0067] Specifically, in this embodiment, the protruding structure 4 includes heat dissipation pillars extending along the side away from the insulating layer 2, and the heat dissipation pillars are arranged in an array. The arrayed heat dissipation pillars, combined with the aforementioned heat dissipation metal plate 1, can form a PIN-FIN heat dissipation structure, wherein the heat dissipation metal plate 1 serves as the base of the PIN-FIN heat dissipation structure. This structure can ensure that the power substrate has excellent heat dissipation performance, and ultimately can further enhance the heat dissipation capability of the power module.

[0068] In this embodiment, the electrical connection layer 3 is a fluid metal layer that is used to fix the power chip 5 at a first temperature. In this application, the power substrate and power chip 5 are soldered together at a relatively high temperature, referred to as the first temperature in this embodiment. In this embodiment, the electrical connection layer 3 needs to be fluid when the power substrate and power chip 5 are soldered at the first temperature. At this temperature, the electrical connection layer 3 itself can act as solder to solder the insulating layer 2 and power chip 5 together, without the need for additional solder. Therefore, after encapsulating the power chip 5, this structure can further reduce the use of one layer of solder in the heat dissipation path from the power chip 5 to the heat dissipation structure, thereby further improving heat dissipation performance. Furthermore, by setting the electrical connection layer 3 to be a fluid metal layer at the first temperature, warping between the electrical connection layer 3 and the insulating layer 2 due to the difference in thermal expansion coefficients can be further avoided when soldering the power chip 5. The fluid electrical connection layer 3 can also effectively fill the gap between the insulating layer 2 and the power chip 5, ensuring a tight bond between them. The electrical connection layer 3 mentioned above at the first temperature can be in a liquid or semi-solid state, and there is no specific limitation here, as long as it has fluidity.

[0069] Typically, the aforementioned metal layer, which is in a liquid or semi-solid state at the first temperature, needs to be patterned. The purpose of this patterning is to ensure the formation of specific circuitry for easy electrical connection of the power chip 5, while also preventing the electrical connection layer 3 from flowing out of the insulating layer 2 and contacting the heat dissipation metal plate 1 at the first temperature. Because this metal layer is fluid at the first temperature, it further prevents gaps between the electrical connection layer 3 and the insulating layer 2 caused by differences in their coefficients of thermal expansion during the soldering process. Simultaneously, the electrical connection layer 3 can directly fill the gaps between the insulating layer 2 and the power chip 5 caused by slight differences in their coefficients of thermal expansion, ensuring that the insulating layer 2 can maintain a flat plate structure. In this embodiment, the electrical connection layer 3 can be an aluminum-based active metal (Al-Si-Ti series), and its specific material can be determined according to actual conditions; no specific limitations are made here.

[0070] In another feasible example, a solder layer is provided on the surface of the electrical connection layer 3 facing away from the insulating layer 2. This solder layer is used to fix the power chip 5. When the electrical connection layer 3 is a metal layer that is still solid at the first temperature, such as an aluminum layer or a copper layer, a solder layer can be further provided on the surface of the electrical connection layer 3 facing away from the insulating layer 2 in this example. This solder layer ensures a fixed connection between the power chip 5 and the electrical connection layer 3 during soldering. This solder layer also needs to be fluid at the first temperature to further avoid gaps between the electrical connection layer 3 and the power chip 5 due to differences in thermal expansion coefficients during soldering, ensuring that the insulating layer 2 can have a flat plate structure. The specific material of the solder layer can be set according to the actual situation and is not specifically limited here.

[0071] Of course, if the electrical connection layer 3 is a metal layer that remains solid at the first temperature, such as an aluminum layer or a copper layer, the electrical connection layer 3 can be fixedly connected to the insulating layer 2 by solder. In this embodiment, the heat dissipation metal plate 1 is preferably an aluminum plate or an aluminum alloy plate.

[0072] The power substrate provided in this embodiment can further improve heat dissipation by setting a raised structure 4, reducing the length of the heat dissipation path and helping to improve heat dissipation performance. Using a metal layer with fluidity at a first temperature as the electrical connection layer 3 can further ensure that the power substrate can still form a good electrical connection with the power chip 5 under the flat structure, further reducing the failure problem caused by the inconsistency of the thermal expansion coefficients between the power chip 5 and the insulating layer 2, improving the reliability of the power module, and ensuring the product production yield.

[0073] By using liquid metal to form the electrical metal layer 3, the failure of the power chip 5 caused by inconsistent thermal expansion coefficients is further avoided, improving the production yield of the power module and reducing cost losses. Compared with the thermal stress compensation structure of the existing heat dissipation base plate, this application does not require an arc design, has a thin solder layer, good welding quality, low residual stress, low risk of leakage, and high reliability.

[0074] Example 3

[0075] Please refer to Figures 3 to 6 , Figure 3 An exploded view of a power module provided for an embodiment of this utility model; Figure 4 This is a schematic diagram of the structure of a power module provided in an embodiment of the present utility model; Figure 5 This is a top view of a power module fabricated in this embodiment; Figure 6 for Figure 5 A sectional view along line AA.

[0076] See Figures 3 to 6This embodiment also provides a power module, which includes a power chip 5 and a power substrate as provided in any of the above utility model embodiments. Specifically, the power chip 5 is fixedly connected to the electrical connection layer 3, thereby achieving a fixed connection between the power chip 5 and the power substrate. The structure of the power substrate can be referred to in the above embodiments and will not be repeated here. The specific structure of the power chip 5 can be referred to in the prior art, and will also not be repeated here.

[0077] In addition to the power chip 5 and power substrate mentioned above, the power module typically includes a cover plate 10, a housing 8, power pins 7, bonding wires 6, and encapsulating colloid 9. Specifically, the power chip 5 can be arranged in a bridge circuit on the electrical connection layer 3, the bonding wires 6 are used for electrical connections between power chips 5 and with external circuits, the power pins 7 are used for controlling and sampling the power chip 5, and the entire module is encapsulated by the housing 8, then potted, dried, and molded.

[0078] For example, the power module shown in this application is a three-phase full-bridge power module with an HPD package. It can also be a half-bridge module or an H-bridge module, and the package can also be ME4, HP1, etc. This application does not impose any fixed limitations.

[0079] Since the power module of this embodiment is provided with the power substrate provided in the above-described utility model embodiment, the manufacturing cost of the power module is lower, the result is simpler, the heat dissipation is more efficient, and the performance is more stable.

[0080] The power substrate of this application exhibits a high degree of matching between its thermal expansion coefficient and that of the power chip 5. Whether during vacuum high-temperature reflow soldering in the production process or in the high-temperature operating environment of the module, the deformation of the power substrate is consistent with that of the power chip 5, reducing the risk of power chip 5 failure and improving the reliability of the power module. Furthermore, the power substrate of this application uses silicon wafers as the substrate, resulting in low material cost and high thermal conductivity, which is beneficial for reducing the size of the power chip 5 and the volume of the power module. Moreover, the use of an active metal as the electrical connection layer 3 further reduces the risk of power chip 5 failure, significantly improving product yield.

[0081] Compared to traditional power modules, this application's power module reduces the copper foil layer between the power substrate and the heat dissipation metal plate 1, significantly lowering the overall thermal resistance of the power module. Simultaneously, it utilizes a metal with high thermal conductivity as the electrical connection layer 3. Due to its excellent flexibility at high temperatures, it further avoids power chip 5 failure caused by inconsistent thermal expansion coefficients, further improving the production yield of the power module. This application's power module has a lightweight structure, reduces multiple metal layers and solder, and features low cost and high reliability.

[0082] This application's power substrate requires no curved design or micro-curvature, features a thin solder layer, high welding quality, low residual stress, low leakage risk, and high reliability. This application reduces thermal resistance, increasing the lateral heat dissipation capacity of the power module by 10 to 30 times while reducing material usage, thus improving heat dissipation performance while maintaining reliability. The manufacturing process of this application is significantly different from existing technologies. By using a high-temperature, fluid metal layer, it improves production yield, reduces void ratio, and enhances product reliability, making it suitable for industrial mass production applications.

[0083] In this application, the insulating layer 2 is made of the same silicon material as the power chip 5, which facilitates synchronized thermal expansion and solves the problem of chip tearing caused by deformation due to thermal stress during the welding process of the power chip 5. At the same temperature, the deformation of both is the same with minimal error, avoiding tearing and damage to the power chip 5 due to deformation differences caused by the different thermal expansion coefficients of the power chip 5 and the power substrate during welding. This application heats the electrical connection layer 3 to a semi-molten state and welds it to the power chip 5. Compared to traditional solder connections, this process is simpler and lower in cost. Furthermore, due to the good flexibility and low void ratio of this metal, the product yield is high.

[0084] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0085] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] The power substrate and power module provided by this utility model have been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A power substrate, characterized in that, include: Heat dissipation structure; the heat dissipation structure includes a heat dissipation metal plate, and a groove is provided on one side surface of the heat dissipation metal plate; An insulating layer fixed to the bottom surface of the groove; An electrical connection layer is disposed on the surface of the insulating layer away from the heat dissipation metal plate; the distance between the top surface of the electrical connection layer and the bottom surface of the groove is not less than the depth of the groove, and the electrical connection layer is isolated from the sidewall of the groove; The heat dissipation metal plate is provided with a connection structure that connects to the outer casing.

2. The power substrate of claim 1, wherein, The top surface of the electrical connection layer is flush with the top surface of the groove sidewall.

3. The power substrate of claim 1, wherein, There is a first gap between the side of the insulating layer and the sidewall of the groove; and / or, there is a second gap between the edge of the electrical connection layer and the edge of the insulating layer.

4. The power substrate of claim 1, wherein, The heat dissipation structure also includes a protruding structure located on the surface of the heat dissipation metal plate away from the insulating layer.

5. The power substrate of claim 4, wherein, The protruding structure includes heat dissipation columns extending along the side away from the insulating layer, and the heat dissipation columns are distributed in an array.

6. The power substrate of claim 1, wherein, The insulating layer includes a main layer made of the same material as the substrate in the power chip to be bonded. The main layer has an insulating film layer on at least the surface on which the electrical connection layer is disposed. The electrical connection layer is isolated from the main layer through the insulating film layer.

7. The power substrate of claim 6, wherein, The insulating layer includes a silicon wafer, wherein the silicon wafer has an oxide layer on at least the exposed surface.

8. The power substrate according to any one of claims 1-7, characterized in that, When the power chip is fixed at the first temperature, the electrical connection layer is a fluid metal layer.

9. The power substrate of any of claims 1-7, wherein, The heat dissipation metal plate is any one of the following: Aluminum heat sink, aluminum alloy heat sink, copper heat sink, copper-aluminum alloy heat sink.

10. A power module, characterized in that, It includes a power chip and a power substrate as described in any one of claims 1 to 9, wherein the power chip is fixedly connected to the electrical connection layer.

Images