the conventional substrate on the market is mainly FR-4 substrate and metal substrate. The FR-4 substrate is characterized by organic matter, with poor radiation resistance, poor thermal conductivity and poor high temperature resistance. The metal substrate needs to stick the metal line, polymer insulation layer and metal substrate together. The thermal conductivity of polymer insulation layer and binder is generally low. The thermal conductivity of polymer insulation layer is about 1~3 W / (m · k), and the thermal conductivity of binder is 1 W / (m.· K) Around, the insulation layer and the adhesive significantly block the heat conduction from the line to the substrate. The aluminum nitride ceramic substrate can well overcome the above shortcomings. Therefore, in recent years, the research on aluminum nitride ceramic substrate has attracted much attention. In order to deepen the metallization and application of aluminum nitride ceramic substrate, researchers still need to make more efforts。