Metallized Al2O3 Alumina Ceramic PCB Direct Bond Copper DBC Substrate
DBC substrate is extensively used in a variety of Insulated gate bipolar diode (IGBT), laser devices (LD) and focused photovoltaic (CPV) and other high power devices package with heat dissipation application. Especially, alumina DBC substrates take a big part in the application because of its outstanding features.
1. High thermal conductivity: The thermal conductivity of alumina ceramics is about 24~28 W/(m·K), which is lower than aluminum nitride (AlN), but the DBC structure quickly dissipates heat through the copper layer, and the overall thermal performance is excellent.
2. Low coefficient of thermal expansion (CTE): The CTE of alumina (7~8 ppm/ºC) is close to that of silicon chips (4 ppm/ºC), reducing thermal stress.
3. High current carrying capacity: The copper layer has good conductivity and can carry large currents (such as 50 A/mm²).
4. Dielectric strength: The breakdown voltage is as high as 20 kV/mm, suitable for high-voltage applications.
5. Mechanical strength: The bending strength is 300~400 MPa, which is better than ordinary PCBs.


Q1: What are the main advantages of alumina DBC substrates?
A: High insulation (>10 kV/mm), excellent heat dissipation capability (thermal conductivity 24~28 W/(m·K)), low thermal expansion coefficient (matching silicon chip), large current carrying capacity (copper layer thickness 0.1~0.6 mm), suitable for high power and high temperature environments.
Q2: How does the alumina content (96% vs 99%) affect performance?
A: 99% alumina has higher purity, slightly better thermal conductivity (increased by about 10%), and stronger mechanical strength, but the cost is slightly higher; 96% alumina is more cost-effective and suitable for most conventional applications.
Q3: What application scenarios are DBC substrates suitable for?
A: Power modules (IGBT/SiC/GaN), high-power LED packaging, new energy vehicle electronic control systems, industrial power supplies, RF devices and other fields that require high heat dissipation and insulation.
Q4: How to choose the copper layer thickness?
A:
0.1~0.2 mm: suitable for small current, high-precision circuits (such as radio frequency).
0.3~0.6 mm: suitable for high-power devices (such as electric vehicle inverters), with stronger current carrying capacity.
Q5: Can the graphic design be customized? What is the minimum line width?
A: Customized etching circuit graphics are supported. The conventional minimum line width is 100 μm, and the laser process can achieve 50 μm (cost assessment required).
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