In addition, with the rapid development of modern power electronics technology characterized by high voltage, high current and high frequency, the heat dissipation efficiency of power modules applied to this technology has become the key. Ceramic bobbin materials in electronic packaging systems are the key to efficient heat dissipation, and should also have high strength and reliability in order to cope with the complexity of the working environment.At present, the call for Ceramic Core Immersion Heaters protecting the environment and saving energy is high, which makes domestic new energy electric vehicles attract much attention. High-power packaged devices play a decisive role in regulating automotive speed and storage-conversion AC and DC. The high frequency of thermal cycling puts forward strict requirements for the heat dissipation of electronic packaging, and the complexity and diversity of the working environment require the packaging material to have better thermal shock resistance and high strength to play a supporting role.

In recent years, ceramic spools that have been mass-produced and widely used mainly include: Al2O3, BeO, SiC, Si3N4, AlN, etc. Properties of different types of ceramic bobbins (Source: Liao Shengjun. Preparation steatite c221 and Performance Of Silicon Nitride Ceramic Materials for Substrates). Al2O3 currently occupies an important position in the heat dissipation substrate industry due to its simple preparation process, good insulation and high temperature resistance. However, the low thermal conductivity of Al2O3 cannot meet the development requirements of high-power and high-voltage devices, and is only suitable for working environments with low heat dissipation requirements, and due to the low bending strength, the application range of Al2O3 ceramics as a heat dissipation substrate is also limited. Although the BeO ceramic spool has a high thermal conductivity and a low dielectric constant, it meets the requirements of efficient heat dissipation, but because of its toxicity, it has an impact on the health of the staff and is not conducive to large-scale application. AlN ceramics have high thermal conductivity and are considered candidate materials for heat dissipation substrates.

In addition, the coefficient of thermal expansion of the Si3N4 ceramic bobbin is close to that of the SiC crystal of the 3rd generation semiconductor substrate, making it able to match the SiC crystal material more stably. This makes Si3N4 the first choice for high thermal conductivity substrate materials for 3rd generation SiC semiconductor power devices. Silicon nitride is recognized at home and abroad as the best cordierite c520 ceramic bobbin material with high thermal conductivity, high reliability and other comprehensive performance. Although the Si3N4 ceramic bobbin has a slightly lower thermal conductivity than AlN, its bending strength and fracture toughness can reach more than 2 times that of AlN; At the same time, the thermal conductivity of Si3N4 ceramics is much greater than that of Al2O3 ceramics.