Aluminum nitride substrate and silicon carbide semiconductor compounded efficient heat dissipation structure
By using a composite structure of aluminum nitride substrate and silicon carbide semiconductor, and employing gradient metal layers and microporous copper pillars, the problem of thermal expansion coefficient mismatch is solved, achieving efficient heat dissipation and improving device reliability and lifespan.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA ROLLARY DIGITAL TECH SHANGHAI
- Filing Date
- 2025-04-21
- Publication Date
- 2026-04-21
AI Technical Summary
In existing technologies, the mismatch in thermal expansion coefficients between aluminum nitride substrates and silicon carbide semiconductors leads to interfacial stress, creating a bottleneck in traditional heat dissipation paths and affecting device reliability and lifespan.
It adopts a composite structure of aluminum nitride substrate and silicon carbide semiconductor, and mitigates the difference in thermal expansion coefficient through gradient metal layer. Combined with microporous copper pillars and heat dissipation fin design, it enhances the continuity of heat conduction and heat dissipation efficiency.
It significantly reduces overall thermal resistance by 40%, reduces interfacial stress by 30%, increases vertical thermal conductivity to 280 W/m·K, and keeps module temperature rise below 15℃, thereby improving device reliability and lifespan.
Smart Images
Figure CN224154616U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat dissipation technology for semiconductor devices, specifically a high-efficiency heat dissipation structure composed of an aluminum nitride substrate and a silicon carbide semiconductor. Background Technology
[0002] As power devices evolve towards higher frequencies and higher power densities, heat dissipation has become a critical factor limiting device reliability and lifespan. Traditional alumina (Al2O3) substrates have low thermal conductivity (approximately 24 W / m·K), while aluminum nitride (AlN) substrates have even higher thermal conductivity (170-230 W / m·K), but the matching of their coefficient of thermal expansion (CTE) with that of semiconductor devices still needs optimization. Although silicon carbide (SiC) semiconductors possess high thermal conductivity (approximately 490 W / m·K) and high-temperature resistance, under high-power conditions, if heat cannot be quickly dissipated, the junction temperature will still rise, affecting performance. In existing technologies, the bonding between the substrate and the semiconductor often uses a single material or simple welding, resulting in bottlenecks in the heat dissipation path. Therefore, a structural innovation is urgently needed to achieve efficient heat dissipation through material combination and thermal channel optimization. Utility Model Content
[0003] In view of the problems existing in the prior art, the present invention provides a high-efficiency heat dissipation structure composed of an aluminum nitride substrate and a silicon carbide semiconductor, comprising:
[0004] An aluminum nitride substrate layer, wherein the bottom surface of the aluminum nitride substrate layer is metallized to form a solder layer for connection with an external heat sink;
[0005] A silicon carbide semiconductor layer, wherein the silicon carbide semiconductor layer is directly bonded to the surface of the aluminum nitride substrate layer by thermally conductive solder;
[0006] A transition layer is disposed between the aluminum nitride substrate layer and the silicon carbide semiconductor layer. The transition layer is a gradient metal layer used to alleviate interfacial stress caused by the difference in thermal expansion coefficients and to enhance the continuity of thermal conduction.
[0007] As a preferred embodiment of this utility model, the aluminum nitride substrate layer is provided with an array of micropores or embedded copper pillars to construct a rapid heat conduction path in the vertical direction.
[0008] As a preferred embodiment of this utility model, the edge of the aluminum nitride substrate layer is provided with heat dissipation fins or an extended copper layer to increase the heat dissipation surface area and accelerate the diffusion of heat to the surrounding environment.
[0009] As a preferred embodiment of this utility model, the surface of the silicon carbide semiconductor layer is coated with a heat dissipation layer, which is made of graphene film to enhance the heat radiation heat dissipation capability.
[0010] As a preferred embodiment of this utility model, the metallization treatment of the welding layer adopts a copper plating or nickel plating process.
[0011] As a preferred embodiment of this utility model, the thermally conductive solder is made of nano-silver paste or Au-Sn alloy.
[0012] As a preferred embodiment of this utility model, the gradient metal layer is a Ti / Mo / Cu multilayer structure.
[0013] By adopting the above technical solution, this utility model has the following beneficial effects:
[0014] 1. By directly bonding AlN substrate to SiC device, the thermal resistance of the intermediate layer of traditional DBC substrate is reduced, and the overall thermal resistance is reduced by more than 40%.
[0015] 2. The gradient metal layer and microporous copper pillar design reduce interfacial thermal stress by 30%, while increasing vertical thermal conductivity to 280 W / m·K.
[0016] 3. The heat dissipation fins are combined with the radiation coating, which can control the module temperature rise to within 15℃ (200W operating condition) under natural convection conditions.
[0017] This invention adopts a three-dimensional heat dissipation enhancement design, which significantly improves heat dissipation efficiency and is suitable for high-power power electronic modules, high-frequency devices and high-temperature application scenarios. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0019] In the diagram: 1. External heat sink; 2. Solder layer; 3. Aluminum nitride substrate layer; 4. Transition layer; 5. Heat dissipation fins; 6. Arrayed micropores; 7. Silicon carbide semiconductor layer; 8. Heat dissipation layer. Detailed Implementation
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0021] Example 1
[0022] like Figure 1 As shown, this utility model discloses a high-efficiency heat dissipation structure composed of an aluminum nitride substrate and a silicon carbide semiconductor. Through material matching, interface optimization, and three-dimensional thermal channel design, it significantly improves heat dissipation efficiency.
[0023] Composite structure design
[0024] Aluminum nitride substrate layer 3: High thermal conductivity AlN ceramic is used as the substrate body. Its bottom surface is metallized with copper plating (nickel plating can be used in other embodiments) to form a welding layer 2, which facilitates connection with external heat sink 1. The metallized welding layer 2 can effectively reduce the contact thermal resistance when connected with external heat sink 1 and improve the heat transfer efficiency.
[0025] Silicon carbide semiconductor layer 7: SiC power devices (such as MOSFETs or diodes) are directly bonded to the surface of the AlN substrate using high thermal conductivity solder nano silver paste (Au-Sn alloy can be used in other embodiments) to form a low thermal resistance interface. The use of high thermal conductivity solder enables good thermal conduction between the silicon carbide semiconductor device and the aluminum nitride substrate, reducing the accumulation of heat at the interface.
[0026] Transition layer 4: A gradient metal layer is added between the AlN substrate and the SiC device: a Ti / Mo / Cu multilayer structure, to alleviate the interface stress caused by the CTE difference and enhance the continuity of heat conduction. Since there is a difference in the coefficient of thermal expansion between the aluminum nitride substrate and the silicon carbide semiconductor device, interface stress is easily generated when the temperature changes during operation. The gradient metal layer can effectively buffer this stress, ensuring the stability and reliability of the structure. At the same time, its good thermal conductivity also enhances the continuity of heat conduction.
[0027] Enhanced heat dissipation design
[0028] Vertical heat channel: An array of micro-holes 6 (embedded copper pillars can be used in other embodiments) is designed inside the AlN substrate. The high thermal conductivity of copper (about 400 W / m·K) is used to build a fast vertical heat conduction path. The array of micro-holes 6 or embedded copper pillars can form an efficient vertical heat dissipation channel inside the aluminum nitride substrate, so that heat can be quickly transferred from the silicon carbide semiconductor device to the outside.
[0029] Lateral extension structure: Heat dissipation fins 5 are provided at the edge of the AlN substrate (an extended copper layer may be used in other embodiments) to increase the heat dissipation surface area and accelerate the diffusion of heat to the surrounding environment. The setting of heat dissipation fins 5 greatly increases the contact area between the heat dissipation structure and the surrounding environment. According to the principle of heat transfer, it can significantly improve the speed of heat diffusion to the surrounding environment, thereby improving the overall heat dissipation efficiency.
[0030] Auxiliary heat dissipation layer 8: A high emissivity material is coated on the surface of the SiC device. In this embodiment, a graphene film is used to enhance the heat radiation heat dissipation capability, which can enhance the heat radiation effect on the surface of the silicon carbide device and improve the heat dissipation efficiency.
[0031] The working principle of this invention is as follows: In the actual manufacturing process, the aluminum nitride substrate layer 3 is first metallized. A copper plating or nickel plating process is selected to form a welding layer 2 on its bottom surface. Then, a high thermal conductivity solder, such as nano-silver paste or Au-Sn alloy, is used to precisely bond the silicon carbide power device to the surface of the aluminum nitride substrate. Before bonding, a Ti / Mo / Cu multilayer gradient metal layer is set between the two. For the construction of vertical heat channels inside the aluminum nitride substrate, an array of micro-holes 6 or embedded copper pillars can be formed through precision machining technology. At the edge of the substrate, heat dissipation fins 5 or an extended copper layer is set according to design requirements. Finally, a high emissivity material such as a graphene film is uniformly coated on the surface of the silicon carbide device. In practical applications, this heat dissipation structure is tightly connected to the external heat sink 1 through the welding layer 2. When the silicon carbide semiconductor device generates heat during operation, the heat is quickly and efficiently transferred and dissipated into the surrounding environment through the aforementioned composite structure and heat dissipation enhancement structure, effectively reducing the device's operating temperature and improving its reliability and service life.
[0032] All components mentioned in this article are general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods, so they will not be described in detail here.
[0033] While the specific embodiments of this utility model have been described in detail above, this utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this utility model. Modifications or variations that do not involve creative labor are still within the protection scope of this utility model.
Claims
1. A high-efficiency heat dissipation structure of a composite of an aluminum nitride substrate and a silicon carbide semiconductor, characterized by comprising: a silicon carbide semiconductor substrate; an aluminum nitride substrate; and a buffer layer between the silicon carbide semiconductor substrate and the aluminum nitride substrate. include: Aluminum nitride substrate layer (3), the bottom surface of which is metallized to form a welding layer (2) for connection with an external heat sink (1); A silicon carbide semiconductor layer (7) is directly bonded to the surface of the aluminum nitride substrate layer (3) by a thermally conductive solder. A transition layer (4) is disposed between the aluminum nitride substrate layer (3) and the silicon carbide semiconductor layer (7). The transition layer (4) is a gradient metal layer used to alleviate the interfacial stress caused by the difference in thermal expansion coefficients and enhance the continuity of thermal conduction.
2. The high efficient heat dissipating structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that: The aluminum nitride substrate layer (3) is provided with an array of micropores (6) or embedded copper pillars to construct a fast heat conduction path in the vertical direction.
3. The high-efficiency heat dissipation structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that: The edge of the aluminum nitride substrate layer (3) is provided with heat dissipation fins (5) or an extended copper layer to increase the heat dissipation surface area and accelerate the diffusion of heat to the surrounding environment.
4. The high efficient heat dissipating structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that: The surface of the silicon carbide semiconductor layer (7) is coated with a heat dissipation layer (8), which is made of graphene film to enhance the heat radiation heat dissipation capability.
5. The high efficient heat dissipating structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that, The metallization of the welding layer (2) is performed using a copper plating or nickel plating process.
6. The high efficient heat dissipating structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that, The thermally conductive solder is made of nano-silver paste or Au-Sn alloy.
7. The high efficient heat dissipating structure of aluminum nitride substrate and silicon carbide semiconductor composite according to claim 1, characterized in that, The gradient metal layer has a Ti / Mo / Cu structure.