Silicon nitride-based composite material and preparation method thereof

Abstract

The invention provides a silicon nitride-based composite material and a preparation method thereof. Specifically, the preparation method comprises the following steps: preparing mixed powder of silicon nitride powder and a boron nitride precursor into nano-grade boron nitride modified silicon nitride powder in a high-temperature furnace with introduced ammonia gas; carrying out ball milling on thenano-grade boron nitride modified silicon nitride powder and a sintering auxiliary agent in absolute ethyl alcohol and mixing; after drying and sieving, sintering to obtain dense silicon nitride-based composite material; then carrying out high-temperature heat treatment on the obtained dense silicon nitride-based composite material in a nitrogen protection atmosphere furnace for a long time to prepare the silicon nitride-based composite material with high thermal conductivity, high bending strength and high toughness. By adopting the silicon nitride-based composite material, the performance requirements on packaging materials of large-power electronic devices and wave-transparent window materials of hypersonic vehicles are met.

Description

technical field [0001] The invention relates to the technical field of material preparation, in particular to a silicon nitride-based composite material and a preparation method thereof. Background technique [0002] In recent years, with the development of semiconductor industry and microelectronics technology, the integration level of integrated circuits has been continuously improved, and the power consumption of integrated circuit chips has been greatly increased. Since a large part of the energy of the electronic device is converted into heat output while the electronic device is working, and the greater the power, the more heat needs to be dissipated. If the heat is not dissipated in time, the heat accumulation will cause the junction temperature to rise and the output power of the device will be reduced. decreases, shortening device life. At present, the heat dissipation problem of high-power devices has become the main bottleneck restricting the development of power...

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Problems solved by technology

[0004] Silicon nitride ceramics have high mechanical properties, theoretically high thermal conductivity, small dielectric constant, low dielectric loss, linear expansion coefficient close to silicon, non-toxic, environmentally friendly, good heat resistance and thermal shock resistance and High chemical stability and other characteristics have great potential as a high-performance heat dissipation substrate material. However, silicon nitride-based composite materials obtained by conventional preparation processes have low thermal conductivity, which is much smaller than the highest theoretical thermal conductivity of silicon nitride. rate (450W / m·K), silicon nitride with a thermal conductivity greater than 100W / m·K can be obtained through high temperature and long-term heat treatment, but its mechanical properties are low, and it is difficult to meet the performance requirements of high-performance packaging substrate materials

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