Heat dissipation substrate, power module, and method for manufacturing heat dissipation substrate
By using a heat dissipation substrate structure with microchannels on the flow guide plate, the heat dissipation path is simplified, the heat dissipation speed and the reliability of the power module are improved, the production cost and process difficulty are reduced, and the problem of complex heat dissipation mechanism of traditional power module is solved.
Patent Information
- Application Number
- CN202511066994.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-21
AI Technical Summary
Traditional power modules have complex heat dissipation mechanisms, high thermal resistance, and low thermal conductivity of thermal grease, resulting in poor heat conduction and affecting the operational reliability of the power module.
The device employs a guide plate, a first heat dissipation plate, and a second heat dissipation plate. The guide plate is equipped with microchannels, the first heat dissipation plate forms a conductive layer, and the second heat dissipation plate is equipped with liquid inlet and liquid outlet holes. Heat is dissipated through the cooling liquid in the microchannels, simplifying the heat dissipation path.
It improves heat dissipation speed, reduces production costs and process difficulty, enhances the reliability and power density of power modules, and reduces product size.
Smart Images
Figure CN120998900A_ABST
Abstract
Description
Technical Field
[0001] This application relates to semiconductor technology, and more particularly to a heat dissipation substrate and a power module using the heat dissipation substrate. Background Technology
[0002] With the rapid development of high-power devices and wide-bandgap devices, the power density of power semiconductors is increasing year by year, the switching speed is getting faster and faster, the operating frequency is getting higher and higher, and the heat flux per unit area of power chips is continuously increasing. Thermal management of power chips has become a key bottleneck problem restricting the application of power modules.
[0003] Traditional power module heat dissipation mechanisms are complex, such as... Figure 1 As shown, an upper copper layer 13 is provided on the upper surface of the ceramic layer 14, and the power chip 11 is soldered to the upper surface of the upper copper layer 13 through a solder layer 12. A lower copper layer 15 is provided on the lower surface of the ceramic layer 14, and the lower copper layer 15 is soldered to the AlSiC substrate 17 through a solder layer 16. The lower surface of the AlSiC substrate 17 is coated with thermal grease 18 to bond the heat sink 19. The heat of the power chip 11 is transferred sequentially through the upper copper layer 13, ceramic layer 14, lower copper layer 15, AlSiC substrate 17, thermal grease 18, and heat sink 19. The multi-layer structure of the heat dissipation system has a large thermal resistance. Furthermore, the thermal conductivity of the thermal grease is low, which restricts the effective conduction of heat and seriously threatens the operational reliability of the power module. Summary of the Invention
[0004] To address one of the aforementioned technical deficiencies, this application provides a heat dissipation substrate and a power module using the heat dissipation substrate.
[0005] According to a first aspect of the embodiments of this application, a heat dissipation substrate is provided, comprising:
[0006] The guide plate is provided with microchannels;
[0007] The first heat sink is fixed to one side of the flow guide plate; the first heat sink has a conductive layer formed on it.
[0008] The second heat sink is fixed to the other side of the guide plate. The second heat sink has an inlet hole and an outlet hole that are respectively connected to the microchannel.
[0009] According to a second aspect of the present application, a power module is provided, including the heat dissipation substrate as described above; and a micropump, the micropump being connected to the inlet and outlet of a second heat dissipation plate via liquid pipelines.
[0010] According to a third aspect of the embodiments of this application, a method for manufacturing a heat dissipation substrate is provided, comprising:
[0011] Microchannels are formed on the guide plate;
[0012] The two sides of the guide plate are fixedly connected to the first heat sink and the second heat sink respectively. The first heat sink forms a conductive layer. The second heat sink is provided with an inlet hole and an outlet hole that are respectively connected to the microchannel.
[0013] The technical solution provided in this application embodiment employs a guide plate, a first heat sink, and a second heat sink. The guide plate has microchannels; the first heat sink is fixed to one side of the guide plate and has a conductive layer, allowing direct mounting of semiconductor devices; the second heat sink is fixed to the other side of the guide plate and has inlet and outlet holes respectively communicating with the microchannels, enabling orderly flow of cooling liquid within the microchannels. The heat from the semiconductor device can be transferred to the cooling liquid solely through the first heat sink and the guide plate, resulting in a shorter heat dissipation path and thus improved heat dissipation speed. Attached Figure Description
[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0015] Figure 1 This is a schematic diagram of the structure of a power module in related technologies;
[0016] Figure 2 This is a schematic diagram of the structure of a heat dissipation substrate provided in an embodiment of this application;
[0017] Figure 3 This is a schematic diagram of the power module provided in an embodiment of this application;
[0018] Figure 4 This is a top view of the flow guide plate in the heat dissipation substrate provided in the embodiment of this application;
[0019] Figure 5 This is a schematic diagram of the manufacturing process of the heat dissipation substrate provided in the embodiments of this application.
[0020] Figure label:
[0021] 11-Power chip; 12-Solder layer; 13-Upper copper layer; 14-Ceramic layer; 15-Lower copper layer; 16-Solder layer; 17-AlSiC substrate; 18-Thermal grease; 19-Heat sink;
[0022] 2-Guide plate; 21-Microchannel;
[0023] 3-First heat sink;
[0024] 4-Second heat sink; 41-Inlet hole; 42-Outlet hole;
[0025] 5-Semiconductor devices;
[0026] 6-Micro pump;
[0027] 7-Active metal brazing filler metal. Detailed Implementation
[0028] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0029] This embodiment provides a heat dissipation substrate that can dissipate heat from semiconductor devices and has a relatively simple structure and good heat dissipation effect.
[0030] like Figures 1 to 4 As shown, the heat dissipation substrate provided in this embodiment includes: a flow guide plate 2, a first heat dissipation plate 3, and a second heat dissipation plate 4. The flow guide plate 2 is provided with microchannels 21, within which cooling liquid can flow. Because semiconductor devices are small in size, the microchannels 21 on the flow guide plate 2 are also very small, at the micrometer level.
[0031] The first heat sink 3 is fixed to one side of the flow guide plate 2, and a conductive layer is formed on the first heat sink 3. A semiconductor device 5, such as a power chip, is then directly mounted on the first heat sink 3 and fixed thereon. Figure 2 As shown, the semiconductor device 5 is electrically connected to the conductive layer, for example, by means of gold wire bonding.
[0032] The second heat sink 4 is fixed to the other side of the guide plate 2. The second heat sink 4 is provided with an inlet hole 41 and an outlet hole 42 that are respectively connected to the microchannel 21.
[0033] The first heat sink 3 and the second heat sink 4 are respectively fixed on both sides of the guide plate 2. Cooling liquid is injected into the microchannel 21 through the liquid inlet 41 of the second heat sink 4. The cooling liquid flows orderly in the microchannel 21 and is discharged from the liquid outlet 42, carrying away the heat of the semiconductor device and achieving heat dissipation. A conductive layer is formed on the first heat sink 3, which can directly fix the semiconductor device. The heat of the semiconductor device can be transferred to the cooling liquid through only the first heat sink 3 and the guide plate 2, resulting in a shorter heat dissipation path and thus improving the heat dissipation speed.
[0034] The technical solution provided in this embodiment employs a guide plate, a first heat sink, and a second heat sink. The guide plate has microchannels; the first heat sink is fixed to one side of the guide plate and has a conductive layer, allowing direct mounting of semiconductor devices; the second heat sink is fixed to the other side of the guide plate and has inlet and outlet holes respectively communicating with the microchannels, enabling orderly flow of cooling liquid within the microchannels. The heat from the semiconductor device is transferred to the cooling liquid solely through the first heat sink and the guide plate, resulting in a shorter heat dissipation path and thus improved heat dissipation speed.
[0035] In the above scheme, the microchannel 21 can be a guide groove, for example, a guide groove can be etched on one side of the guide plate 2 to form the microchannel 21. The surface of the second heat sink 4 is flat and fixed to the side of the guide plate 2 where the guide groove is provided. After the second heat sink 4 is fixed to the guide plate 2, a closed microchannel 21 is formed. At the location where the guide groove is formed, a portion of the microchannel 21 is reserved to improve the insulation capability.
[0036] In another embodiment, the guide plate 2 includes a double-layer plate, with guide grooves etched on each layer, and the guide grooves in the double-layer plate forming a microchannel 21.
[0037] In another design, the guide plate 2 comprises three layers, with a permeable flow channel in the middle layer. The outer two layers can be flat plates or have flow channels, forming a microchannel 21 between the outer two layers and the middle plate. In this design, through holes corresponding to the liquid inlet 41 and liquid outlet 42 are formed on the plate connected to the second heat sink 4.
[0038] The microchannel 21 can be annular, spiral, serpentine, or other shapes. Figure 4 The microchannel 21 shown is serpentine.
[0039] This embodiment provides an implementation method: the guide plate 2 is a ceramic plate, and the surface of the ceramic plate can be etched using plasma etching technology to process microchannels 21. The cross-section of the microchannels 21 is semi-circular, but it can also be other shapes. For example, the guide plate 2 is made of Si3N4, which has good thermal conductivity.
[0040] The first heat sink 3 is a copper plate, and a conductive layer is formed through an exposure, development, and etching process. For example, the first heat sink 3 is first fixed to the flow guide plate 2, and then a portion of the copper is removed through an exposure, development, and etching process. The remaining copper forms the conductive layer and the corresponding electrode pads. The second heat sink 4 can also be a copper plate, which has good heat dissipation capabilities. The exposure, development, and etching process can specifically include processes such as bonding, photo printing, exposure, development, etching, and stripping.
[0041] One implementation involves printing an active metal solder 7 onto the surface of the guide plate 2 using a screen printing process, which is then soldered to the second heat sink 4 via an active metal brazing process. For example, the active metal solder 7 is removed from sub-zero temperatures, thawed, centrifuged, and then screen-printed onto the surface of the guide plate 2.
[0042] First, the first heat sink 3, the second heat sink 4, and the flow guide plate 2 printed with active metal solder 7 are bonded and fixed at specific positions. Then, brazing is performed at a specific temperature to achieve eutectic bonding between copper and ceramic. The brazing temperature varies depending on the active metal solder. Active metal solders can be divided into high-temperature solders (active metals include Ti, vanadium V, and molybdenum Mo, with a welding temperature of 1000-1250℃), medium-temperature solders (active metals include silver Ag, copper Cu, and titanium Ti, which are welded under a protective gas or vacuum at 700-800℃), and low-temperature solders (active metals include cerium Ce, gallium Ga, and rhenium Re, with a welding temperature of 200-300℃).
[0043] The above solution achieves liquid cooling by creating microchannels on the flow guide plate, significantly improving power heat dissipation performance. This enhances the reliability and lifespan of power devices. Furthermore, it eliminates the need for additional substrates and heat sinks, greatly reducing production costs and process complexity, while also significantly increasing the power density of the power module and reducing product size. Additionally, the use of active metal solder technology lowers the bonding temperature of the ceramic plate, thereby reducing its thermal stress.
[0044] Based on the above technical solutions, this embodiment also provides a power module, such as... Figure 2 As shown, the power module includes a heat dissipation substrate as described above, a semiconductor device 5 disposed on the first heat dissipation plate, and a micropump 6. The semiconductor device 5 is specifically a power chip. The micropump 6 is connected to the inlet hole 41 and outlet hole 42 of the second heat dissipation plate 4 via liquid conduits.
[0045] Based on the above technical solution, this embodiment also provides a method for manufacturing a heat dissipation substrate, including:
[0046] Step 1: Form microchannels on the guide plate.
[0047] Step 2: Fix the two sides of the guide plate to the first heat sink and the second heat sink respectively. The first heat sink forms a conductive layer; the second heat sink is provided with an inlet hole and an outlet hole that are respectively connected to the microchannel.
[0048] One embodiment is as follows: the guide plate 2 is a ceramic plate, the first heat sink 3 is a copper plate, and the second heat sink 4 is a copper plate. The second heat sink 4 has an inlet hole 41 and an outlet hole 42.
[0049] like Figure 5As shown, a flow channel is first formed on one side of the flow guide plate 2 using a plasma etching process, serving as a microchannel 21. Then, active metal solder 7 is printed on both sides of the flow guide plate 2 using a screen printing process. The first heat sink 3, the flow guide plate 2, and the second heat sink 4 are bonded together in sequence, and then the flow guide plate 2 is welded to the first heat sink 3 and the second heat sink 4 using an active metal brazing process. The liquid inlet 41 and the liquid outlet 42 are connected to the microchannel 21. Finally, a conductive layer is formed on the first heat sink 3 using an exposure and development etching process.
[0050] The above scheme involves setting microchannels on a guide plate; fixing a first heat sink to one side of the guide plate; the first heat sink having a conductive layer that allows direct mounting of semiconductor devices; and fixing a second heat sink to the other side of the guide plate. The second heat sink has inlet and outlet holes respectively communicating with the microchannels, allowing the cooling liquid to flow orderly within the microchannels. The heat from the semiconductor devices can be transferred to the cooling liquid only through the first heat sink and the guide plate, resulting in a shorter heat dissipation path and thus improving the heat dissipation speed.
[0051] Using the above solution, there is no need to add an AlSiC substrate, thermal grease or heat sink, which makes the structure simpler and reduces costs and process flow to a certain extent.
[0052] Traditional solutions use Al2O3 ceramics with a thermal conductivity of 24-28 W / mK, typically employing high-temperature co-fired ceramic (DBC / HTCC) technology. Compared to traditional solutions, the technical solution provided in this embodiment, if the guide plate uses Si3N4 material with a thermal conductivity >90 W / mK, exhibits better thermal conductivity and can further improve the heat dissipation rate. Furthermore, the active metal brazing (AMB) process is used to connect the first and second heat sinks, lowering the bonding temperature and thus reducing the thermal stress on the ceramic plate.
[0053] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0055] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0056] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.
[0057] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A heat dissipation substrate, characterized in that, include: The guide plate is provided with microchannels; The first heat sink is fixed to one side of the flow guide plate; the first heat sink has a conductive layer formed on it. The second heat sink is fixed to the other side of the guide plate. The second heat sink has an inlet hole and an outlet hole that are respectively connected to the microchannel.
2. The heat dissipation substrate according to claim 1, characterized in that, One side of the guide plate is etched to form a guide groove, which serves as a microchannel; the second heat sink is fixed to the side of the guide plate with the guide groove.
3. The heat dissipation substrate according to claim 2, characterized in that, The guide plate is a ceramic plate.
4. The heat dissipation substrate according to claim 3, characterized in that, The second heat sink is a copper plate.
5. The heat dissipation substrate according to claim 4, characterized in that, The surface of the flow guide plate is printed with active metal solder using a screen printing process, so that it can be welded to the second heat sink using an active metal brazing process.
6. The heat dissipation substrate according to claim 2, characterized in that, The flow channels are formed by etching the side of the flow guide plate using a plasma etching process.
7. The heat dissipation substrate according to claim 4, characterized in that, The first heat sink is a copper plate, and a conductive layer is formed by exposure, development and etching processes.
8. A power module, characterized in that, It includes the heat dissipation substrate as described in any one of claims 1-7; and a micropump, the micropump being connected to the inlet and outlet of the second heat dissipation plate via liquid pipelines.
9. A method for manufacturing a heat dissipation substrate, characterized in that, include: Microchannels are formed on the guide plate; The two sides of the flow guide plate are fixedly connected to the first heat sink and the second heat sink respectively, and the first heat sink forms a conductive layer. The second heat sink is equipped with an inlet hole and an outlet hole that are respectively connected to the microchannel.
10. The method for manufacturing a heat dissipation substrate according to claim 9, characterized in that, Microchannels are formed on the guide plate, specifically by forming a guide groove on one side of the guide plate using a plasma etching process, and the guide groove serves as a microchannel.
11. The method for manufacturing a heat dissipation substrate according to claim 10, characterized in that, The flow guide plate is a ceramic plate, the first heat dissipation plate is a copper plate, and the second heat dissipation plate is a copper plate; The two sides of the guide plate are fixedly connected to the first heat sink and the second heat sink, respectively, including: Active metal solder is printed on the surface of the guide plate using a screen printing process. It is welded to the first and second heat sinks using an active metal brazing process.