To provide an apparatus and a method of producing fine particles capable of increasing evaporation efficiency of a material, increasing the production of fine particles and reducing costs by heating the inputted material by a gas heated by thermal plasma. A fine particle production apparatus includes a vacuum chamber, a material feeding device connected to the vacuum chamber and feeding material particles from a material feeding port into the vacuum chamber, electrodes arranged in the vacuum chamber for generating plasma and a collection device connected to the vacuum chamber and collecting fine particles, which produces the fine particles from the material by generating electric discharge inside the vacuum chamber, in which the collection device and the material feeding device are connected by piping, and a material heating and circulation device which heats the material by heat of a gas inside the chamber heated by the plasma through the piping is provided.

To provide an apparatus and a method of producing fine particles capable of increasing evaporation efficiency of a material, increasing the production of fine particles and reducing costs by heating the inputted material by a gas heated by thermal plasma. A fine particle production apparatus includes a vacuum chamber, a material feeding device connected to the vacuum chamber and feeding material particles from a material feeding port into the vacuum chamber, electrodes arranged in the vacuum chamber for generating plasma and a collection device connected to the vacuum chamber and collecting fine particles, which produces the fine particles from the material by generating electric discharge inside the vacuum chamber, in which the collection device and the material feeding device are connected by piping, and a material heating and circulation device which heats the material by heat of a gas inside the chamber heated by the plasma through the piping is provided.

Provided are a novel amino-silyl amine compound and a manufacturing method of a dielectric film containing SiN bond using the same. Since the amino-silyl amine compound according to the present invention, which is a thermally stable and highly volatile compound, may be treated at room temperature and used as a liquid state compound at room temperature and pressure, the present invention provides a manufacturing method of a high purity dielectric film containing a SiN bond even at a low temperature and plasma condition by using atomic layer deposition (PEALD).

Provided are a novel amino-silyl amine compound and a manufacturing method of a dielectric film containing SiN bond using the same. Since the amino-silyl amine compound according to the present invention, which is a thermally stable and highly volatile compound, may be treated at room temperature and used as a liquid state compound at room temperature and pressure, the present invention provides a manufacturing method of a high purity dielectric film containing a SiN bond even at a low temperature and plasma condition by using atomic layer deposition (PEALD).

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

A silicon nitride powder having a specific surface area of 4.0 to 9.0 m.sup.2/g, a phase proportion of less than 40 mass %, and an oxygen content of 0.20 to 0.95 mass %, wherein a frequency distribution curve obtained by measuring a volume-based particle size distribution by a laser diffraction scattering method has two peaks, peak tops of the peaks are present respectively at 0.4 to 0.7 m and 1.5 to 3.0 m, a ratio of frequencies of the peak tops ((frequency of the peak top in a particle diameter range of 0.4 to 0.7 m)/(frequency of the peak top in a particle diameter range of 1.5 to 3.0 m)) is 0.5 to 1.5, and a ratio D50/D.sub.BET (m/m) of a median diameter D50 (m) determined by the measurement of particle size distribution to a specific surface area-equivalent diameter D.sub.BET (m) calculated from the specific surface area is 3.5 or more.

A silicon nitride powder having a specific surface area of 4.0 to 9.0 m.sup.2/g, a phase proportion of less than 40 mass %, and an oxygen content of 0.20 to 0.95 mass %, wherein a frequency distribution curve obtained by measuring a volume-based particle size distribution by a laser diffraction scattering method has two peaks, peak tops of the peaks are present respectively at 0.4 to 0.7 m and 1.5 to 3.0 m, a ratio of frequencies of the peak tops ((frequency of the peak top in a particle diameter range of 0.4 to 0.7 m)/(frequency of the peak top in a particle diameter range of 1.5 to 3.0 m)) is 0.5 to 1.5, and a ratio D50/D.sub.BET (m/m) of a median diameter D50 (m) determined by the measurement of particle size distribution to a specific surface area-equivalent diameter D.sub.BET (m) calculated from the specific surface area is 3.5 or more.

The present invention is a silicon nitride powder having a -conversion rate of 80% or more and having a lattice strain of 1.010.sup.3 or more. According to the present invention, there can be provided a silicon nitride powder having high sinterability even at a low temperature of about 1800 C.

The present invention is a silicon nitride powder having a -conversion rate of 80% or more and having a lattice strain of 1.010.sup.3 or more. According to the present invention, there can be provided a silicon nitride powder having high sinterability even at a low temperature of about 1800 C.