Combined with the comprehensive performance advantages of traditional Al2O3 and BeO substrate materials, Aluminum Nitride(AlN) ceramic, which has high thermal conductivity (monocrystal’s theoretical thermal conductivity is 275W/m▪k，polycrystal’s theoretical thermal conductivity is 70~210W/m▪k) , low dielectric constant, thermal expansion coefficient matched with single crystal silicon, and good electrical insulation properties, is an ideal material for circuit substrates and packaging in the microelectronics industry. It’s also an important material for high temperature structural ceramic components due to the good high temperature mechanical properties, thermal properties and chemical stability.
The theoretical density of AlN is 3.26g/cm3, the MOHS hardness is 7-8, the room-temperature resistivity is greater than 1016Ωm, and the thermal expansivity is 3.5×10-6/℃ (room temperature of 200℃). Pure AlN ceramics are colorless and transparent, but they would be various colors like gray, grayish white or light yellow, due to the impurities.
In addition to high thermal conductivity, AlN ceramics also have the following advantages:
1. Good electrical insulation;
2. Similar thermal expansion coefficient with silicon monocrystal, superior to materials like Al2O3 and BeO;
3. High mechanical strength and similar flexural strength with Al2O3 ceramics;
4. Moderate dielectric constant and dielectric loss;
5. Compared with BeO, the thermal conductivity of AlN ceramics is less affected by temperature, especially above 200℃;
6. High temperature resistance and corrosion resistance;
7. Non-toxic;
8. Be applied to semiconductor industry, chemical metallurgy industry and other industrial fields.
