Aluminum Nitride – the most fashionable substrate material
Since the beginning of the 21st century, with the rapid development of electronic technology, the integration level and assembly density of electronic components have been continuously improved, and heat dissipation has become the key to affecting device performance and reliability.
The packaging substrate is used to export heat from the chip (heat source) to achieve heat exchange with the external environment to achieve the purpose of heat dissipation. Among them, ceramic materials have become a common material for power device packaging substrates due to their high thermal conductivity, good heat resistance, high insulation, high strength, and thermal matching with chip materials.
At present, the demand for aluminum nitride substrates in power semiconductor devices, hybrid integrated power circuits, antennas in the communication industry, solid relays, power LEDs, multi-chip packaging (MCM) and other fields is growing. Its terminal market is for automotive electronics, LEDs, rail transit, communication base stations, aerospace and military defense.
1. Antenna
Antenna can convert guided waves propagating on the transmission line into electromagnetic waves propagating in free space, or convert electromagnetic waves into guided waves. Its essence is a converter. Antennas have a wide range of uses and need to work normally in any environment. Therefore, their components need to be of high and extremely reliable quality. Ordinary circuit boards cannot meet this basic requirement of antennas. At present, the ceramic-based circuit board is the closest to the requirements of antennas in all aspects. Among them, AlN ceramic-based circuit boards have the best performance, which is mainly reflected in:
(1) Small dielectric constant, which reduces high-frequency losses and enables complete signal transmission.
(2) Metal film layer with low resistance and good adhesion. The metal layer has good conductivity and generates less heat when current passes through.
(3) Ceramic-based circuit boards have good insulation. Antennas generate high voltage during use, and ceramic substrates have a high breakdown voltage.
(4) High-density packaging is possible.
2. Multi-chip module (MCM)
Multi-chip module is a high-performance, high-reliability and miniaturized advanced microelectronic component that can meet the strict requirements of aerospace, military electronic equipment, etc. With the increase in component power and the increase in packaging density, good heat dissipation is the key technology to be considered. MCM-C type packaging substrate materials usually adopt a multilayer ceramic structure.
3. High-temperature semiconductor packaging
SiC, GaN and diamond-based wide bandgap semiconductor material devices can work at high temperatures, especially SiC has the most mature application technology; SiC can work stably at a high temperature of 600°C with its excellent physical and chemical properties, and plays an extremely important role in high-temperature electronic systems in the aerospace field.
4. Power semiconductor module
The power semiconductor module is a combination of power electronic components packaged into one according to a certain pattern and functional combination. The power semiconductor module can select appropriate components for packaging according to the required functions. The common ones are insulated gate bipolar transistors, power metal oxide semiconductor field effect transistors and power integrated circuits. Power semiconductor modules have very high heat dissipation requirements. Ceramic circuit boards are one of their main core components and the first contact point of heat.
5. Power LED packaging
LED is a semiconductor chip that converts electricity into light. Scientific research shows that only 20%-30% of electrical energy is effectively converted into light energy, and the rest is lost as heat. If there is no appropriate way to quickly dissipate the heat, the operating temperature of the lamp will rise sharply, resulting in a significant shortening of the life of the LED.
With the continuous upgrading of electronic information industry technology, the miniaturization and functional integration of PCB substrates have become a trend. The market’s requirements for heat dissipation and high temperature resistance of heat dissipation substrates and packaging materials are constantly increasing. It is difficult for ordinary substrate materials with relatively high performance to meet market demand. The development of the aluminum nitride ceramic substrate industry has ushered in opportunities. Therefore, aluminum nitride has become the most popular packaging substrate material at present.