Preparation method of high-thermal-conductivity silicon nitride substrate

Abstract

The invention discloses a preparation method of a high-thermal-conductivity silicon nitride substrate, which belongs to the technical field of ceramic material preparation. Silicon nitride powder is adopted as a raw material, rare earth oxide and alkaline earth metal oxide are added to serve as a mixed sintering aid, the adding amount is 6 wt%-10 wt%, a high-molecular compound is added, ball milling and mixing are conducted in an organic solvent, and slurry is formed. Tape casting is carried out to form a green body, presintering of the green body in nitrogen at 1400-1600 DEG C for 1-5 hours is conducted, and heat preservation in an air pressure sintering furnace at 1800-2000 DEG C for 2-10 hours is carried out under the nitrogen pressure of 0.5-3 MPa. The silicon nitride powder used in the invention is high-purity alpha-phase silicon nitride, has very high specific surface area and high sintering activity, and can effectively reduce the densification temperature. The added high-molecular carbon-containing compound is a multi-component compound and is degreased and pre-sintered in an inert atmosphere, so that the thermal conductivity of the product can be improved. The thermal conductivity of the prepared silicon nitride ceramic substrate is not lower than 90 W / m.K, and the bending strength is not lower than 800 MPa.

Description

technical field

[0001] The invention belongs to the technical field of ceramic material preparation, and relates to a method for preparing a silicon nitride substrate with high thermal conductivity. Background technique

[0002] At present, semiconductor devices are developing toward high power, high frequency, and integration. It is inevitable that devices will generate a lot of heat during operation, which is also the main reason for the failure of semiconductor devices. The thermal conductivity of the insulating substrate is the key to the heat dissipation of the entire semiconductor device, so how to improve the thermal conductivity of the substrate material is very critical. The ceramic substrates currently used in the market are mainly SiC and AlN. SiC ceramics have high thermal conductivity (120-180W / m K), but their dielectric loss is high and their insulation is poor, so their applications are limited; AlN has high thermal conductivity (160-230W / m K). K), but the c...