Method for synthesizing aluminum nitride ceramic powder at low temperature based on surface modification

Abstract

A method for synthesizing aluminum nitride ceramic powder at low temperature based on surface modification, which is carried out in the following steps: (1) prepare aluminum source alumina ultrafine powder, ammonia water, coupling agent and polyethylene glycol; (2) prepare Put the alumina ultrafine powder in absolute ethanol and stir to form a slurry; add ammonia water, coupling agent and polyethylene glycol and stir; (3) filter and then stir in absolute ethanol, and separate and remove by secondary filtration liquid phase; (4) add phenolic resin to absolute ethanol under stirring condition, and stir to form a paste; grind after drying; (5) grind and mix with nitrogen source; (6) air pressure in the heating furnace Raise the temperature to 950-1500°C under the atmospheric pressure to carry out the nitriding synthesis reaction; cool with the furnace; (7) remove carbon under the condition of 550-650°C. The method of the invention has low synthesis temperature, environmental protection and low cost, and has wide application prospects.

Description

technical field [0001] The invention belongs to the technical field of materials, in particular to a method for synthesizing aluminum nitride ceramic powder at low temperature based on surface modification. Background technique [0002] With the rapid development of microelectronics technology, electronic machines and electronic components are developing in the direction of miniaturization, light weight, integration, high reliability and high power output. The heat dissipation of packaging materials puts forward higher requirements; the thermal conductivity of traditional resin substrates and alumina ceramic substrates is below 30W / (m K), which is far from meeting the development needs of large-scale integrated circuits and complex devices; The theoretical thermal conductivity of aluminum nitride ceramics is 320W / (m K), and it has good electrical insulation, low dielectric constant and dielectric loss, a thermal expansion coefficient that matches silicon well, and has good c...

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Problems solved by technology

[0002] With the rapid development of microelectronics technology, electronic machines and electronic components are developing in the direction of miniaturization, light weight, integration, high reliability and high power output. The heat dissipation of packaging materials puts forward higher requirements; the thermal conductivity of traditional resin substrates and alumina ceramic substrates is below 30W / (m K), which is far from meeting the development needs of large-scale integrated circuits and complex devices; The theoretical thermal conductivity of aluminum nitride ceramics is 320W / (m K), and it has good electrical insulation, low dielectric constant and dielectric loss, a thermal expansion coefficient that matches silicon well, and has good chemical properties. With the advantages of stability, environmental protection and non-toxicity, it has become the most ideal substrate material and electronic device packaging material

[0003] The easiest way to produce aluminum nitride powder is the carbothermal reduction method, that is, using alumina as the aluminum source, adding a part of carbon through mechanical mixing, and under high-temperature flowing nitrogen, a carbothermal reduction reaction occurs to form aluminum nitride. Method; the finer the particle size and the higher the activity of alumina powder, the lower the synthesis temperature; the more uniform the mixing of aluminum source, carbon source and nitrogen source, the lower the synthesis temperature required for the synthesis of aluminum nitride powder ; but the existing problem is that the finer the particle size of alumina powder, the easier it is to agglomerate, and the more difficult it is to achieve uniform mixing between the aluminum source and the carbon source, so it is necessary to disperse the alumina powder; on the other hand, alumina powder It is an inorganic material, while the carbon source (such as sucrose or phenolic resin) is an organic material, and the inorganic and organic materials cannot be uniformly mixed by mechanical mixing. Therefore, it is also necessary to modify the surface of the alumina powder to make the aluminum source and carbon source phase In order to ensure that the aluminum source and carbon source are evenly mixed; in addition, people focus on the aluminum source and carbon source, while the influence of nitrogen source is often not taken seriously

So far, the nitrogen sources used are flowing nitrogen or ammonia. Nitrogen is an inert gas, which is a main reason for the high temperature of the carbothermal reduction reaction, while ammonia is a highly corrosive gas that is easy to leak, which poses a threat to production safety and the environment. Protection poses a great threat

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