SILICON NITRIDE POWDER PRODUCTION METHOD, SILICON NITRIDE POWDER, SILICON NITRIDE SINTERED BODY AND CIRCUIT SUBSTRATE USING SAME

摘要

The purpose of the present invention is to provide a silicon nitride sintered body having high mechanical strength and thermal conductivity, and to provide a circuit substrate using said silicon nitride sintered body. Provided is a silicon nitride powder production method which is characterized by performing heating at a rate of 12-100°C/min in the temperature range of 1000-1400°C while fluidizing an amorphous Si-N(-H) compound having an RS/RO ratio of 500 or greater with a continuous sintering furnace, wherein RS (m2/g) is defined as the specific surface area and RO (mass%) as the oxygen content ratio. Further provided is a silicon nitride powder characterized by FS/FSO being 8-25 and FS/FIO being 22 or greater, wherein FSO (mass%) is defined as the content ratio of oxygen present from the particle surface to 3nm directly below the particle surface, FIO (mass%) as the content ratio of oxygen present from 3nm directly below the particle surface further inwards, and FS (m2/g) as the specific surface area; also provided are a silicon nitride sintered body obtained by sintering the silicon nitride powder, and a circuit substrate using said silicon nitride sintered body.