Introduction to the preparation process of industrial ceramic aluminum nitride powder raw materials

Industrial ceramic aluminum nitride has excellent thermal conductivity, so it is often used as a ceramic substrate or ceramic substrate, and can be used in some integrated circuits. Below, Kezhong Ceramic Factory will introduce the preparation process of its powder raw materials.

Aluminum nitride ceramics have excellent thermal conductivity, coefficient of thermal expansion is close to silicon and non-toxic. It is regarded as a new generation of electronic packaging materials, which is very suitable for the packaging of hybrid power switches and microwave vacuum tube packaging shell materials. It is also an ideal material for large-scale integrated circuit substrates, which is also the main use of AIN ceramics.

The preparation process of a high thermal conductivity aluminum nitride ceramic substrate mainly involves three aspects: preparation of aluminum nitride powder, forming process, and sintering process.

Aluminum nitride ceramic substrate: suitable for high-power LED packaging and heat dissipation substrates, IGBT power modules for thin film printed circuits

1、 Powder preparation

The excellent performance of aluminum nitride ceramics is directly related to the performance of raw material powders, and high-performance AIN powders are the key to preparing high thermal conductivity AIN ceramics. There are many methods for preparing AIN powder (see Table 1 below), and each has its own shortcomings. However, they all have a common feature of high cost.

Overall, the carbothermal reduction method of aluminum oxide powder and the direct nitridation method of aluminum powder are relatively mature and have been used in industrial large-scale production, becoming the mainstream preparation process for high-performance AIN ceramic raw materials. At present, there are not many manufacturers who master the production technology of high-performance AIN powder, mainly distributed in Japan, Germany, and the United States.

Among them, the AIN powder produced by the carbon thermal reduction method of aluminum oxide powder used by Japan's Deshan Caoda Company is globally recognized as having the best quality and the most stable performance, basically occupying the AIN powder market. Toshiba, Kyocera, Sumitomo Electronics, and other companies in Japan use this AIN powder for most substrates and packaging. In addition, Dow Chemical Company in the United States has also mastered the technology of producing AIN powder using the carbothermal reduction method of aluminum oxide powder. Japan's Toyo Aluminum Company uses a relatively low-cost aluminum powder direct nitriding method to produce AIN powder, which has good performance and stable thermal conductivity above 170W/m • K. The difference between high-quality AIN powder and average quality aluminum nitride powder is analyzed in the table below.

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