AlN is a covalently bonded crystal with a theoretical density of 3.26g/cm3 and a Mohs hardness of 7-8. It possesses relatively high strength at room temperature, and its strength decreases with increasing temperature more slowly than alumina and silicon nitride. In comparison to other ceramic materials, aluminium nitride exhibits exceptional comprehensive properties, particularly superior thermal conductivity, making it ideal for semiconductor substrates and structural packaging materials, and has tremendous application potential in the electronics industry.
Advantages of AlN Substrate
Superior Thermal Conductivity
Its thermal conductivity is greater than 180 W/m.K, which is 8 times that of alumina, making them dissipate heat produced by electronic components effectively and appropriate for high-power transistors.
Thermal Expansion Coefficient Similar to Silicon
AlN substrate exhibits thermal expansion coefficient comparable to that of silicon(Si). This contributes to the great dependability of Si chips and thermal cycling.
Electrical Insulation
It has excellent electrical insulation, good volume resistivity, and high breakdown strength, making it well-suited for high-voltage applications.
Low Dielectric Constant
It possesses a low dielectric constant as alumina.
High Temperature Stability
It is perfect for high-temperature applications because it maintains structural integrity at high temperatures.
Non-Toxic
AlN substrate is non-toxic as compared to BeO substrate.
General Dimensions of AlN Substrate
The aluminium nitride substrates can be made in the following dimensions:
AlN substrates can be produced in a variety of sizes and shapes, including square, rectangular, and circular ones using waterjet and laser cutting. Please be aware that after cutting, the edges will have black marks, which must be removed with a chemical post-treatment. So please don't cut by yourself if there isn't professional equipment available. Unipretec will cut based on your requirements if you let us know the sizes and shapes you desire.
AlN substrate can also be pre-die cut (scribe lines) and added fiducial marks to enable easy separation into single pieces after printing. Laser machining can also be used to drill holes. The hole size can be as small as 0.2mm.
Surface roughness and flatness are crucial for substrates to be metallized in order to generate conductive channels for electrical signals. AlN substrates can attain a roughness of Ra0.3-0.7um after grinding and lapping. Additionally, they can be polished using either single- or double-sided polishing to achieve a better roughness of Ra0.02-0.05um.
Production Methods of Substrates Made of Aluminum Nitride
Several important processes are involved in the manufacture of aluminum nitride substrates:
In Powder Synthesis
Chemical methods are used to synthesise high-purity aluminum nitride powder; these reactions usually include carbothermal reduction of aluminum oxide in a nitrogen environment or direct nitridation of aluminum.
Forming
The AlN powder is combined with binders and then shaped using methods including extrusion, pressing, or tape casting. We call these sculptural creations green bodies.
Wintering
To strengthen and accomplish densification, the green bodies are sintered in a controlled environment at high temperatures. Improving heat conductivity and sintering are common uses for additives like yttria or rare earth oxides.
Equipment and Finishing
As needed for particular applications, AlN substrates are cut to exact dimensions and surface finishes after sintering. For electrical connection, this might involve procedures like polishing, lapping, and metallization.
Uses of Aluminum Nitride Substrates
electrical power electronics
Power electronics include transistors, diodes, and power modules extensively use AlN substrates. Their great thermal conductivity enhances dependability and performance by helping to disperse heat produced by powerful components.
Technical LEDs
AlN substrates control the heat produced by the LEDs in LED lighting systems, guaranteeing lifetime and best performance.
Devices for Radio and Microwaves
AlN substrates find use in microwave and radio frequency (RF) devices where signal integrity and performance depend on their superior thermal and electrical characteristics.
Semiconductor Packaging
AlN substrates provide semiconductor devices an electrically insulating and thermally conducting platform in semiconductor packaging. This enhances device performance by lowering heat resistance.
Telecomunications
In high-frequency circuits and devices, AlN substrates are utilized for electrical insulation and thermal control in telecommunications equipment.
Devices for Medicine
The dependability and safety of vital medical equipment are ensured by the thermal management and electrical insulating qualities of AlN substrates used in medical electronics.
Engine Electronics
AlN substrates are used in engine control units and sensors among other automotive electronics to regulate heat and guarantee dependable performance in demanding environments.
