What is silicon nitride ceramic substrate made of

Silicon nitride ceramic substrates are mainly made of silicon nitride powder. This material involves a series of complex process steps in the preparation process, including mixing, ball milling, defoaming, extrusion molding, stamping, powder coating (powder spraying), glue removal, sintering, powder cleaning, edge grinding, scanning, grinding, ultrasonic cleaning, spin drying, laser cutting, quality inspection and other processes.

In the mixing stage, silicon nitride powder and yttrium oxide powder are mixed with organic additives. Next, these materials are further mixed and ground through a ball milling process, which is divided into primary ball milling and secondary ball milling. The first ball milling aims to mix solid raw materials with liquid materials, while the second ball milling is for finer mixing and grinding of the slurry. In addition, substances such as PVB resin (binder), polyethylene glycol, and diethyl phthalate (plasticizer) will be added to the slurry. After ball milling, bubbles in the slurry are removed by a defoamer to prepare a casting slurry with a certain colloidal viscosity suitable for casting.

Silicon nitride ceramic substrates are gradually becoming the preferred substrate material for wide bandgap semiconductor devices due to their high thermal conductivity and mechanical properties. This material has a thermal expansion coefficient similar to that of the third-generation semiconductor substrate SiC crystal material, making it more stable to match and particularly suitable for high-frequency, high-pressure, high-temperature and other working scenarios.