Fabrication Technics And Properties Of Black Alumina Substrates Prepared By Tape Casting

Black alumina ceramic substrate has been widely used as multilayer printed wiring ceramic board, electronic packaging, high density packaging substrates owing to its excellent properties such as high strength, high insulation, good light avoiding, and so on. The desiderate problems need to be resolved are the reduction of alumina ceramic sintering temperature and presentation of black color, which could get rid of the import of black alumina package electronic devices. In this paper, by adding low temperature sintering flux and black pigment to alumina, with the method of tape casting, black alumina substrate with good black color and excellent strength is obtained by sintered at low temperature. The crystal structure and the color presentation mechanism were analyzed. The process parameters of tape casting were established. The effects of the additives and the sintering temperature to the shrinkage, density and strength of black alumina have been discussed.The Fe-Cr-Mn system black pigment used for alumina substrate was successfully prepared by dwelling 2 hours at 1250℃. It could avoid high temperature volatility with the crystal structure of spinel. By adding 5% pigment that after milling 4 hours to alumina, it could obtain uniform black color sintering between 1310℃ ～ 1330℃.The parameters of tape casting were optimized: even mixed ceramic powders were obtained by milling 22-24 hours at the first milling stage; the proper volume of green tape that fits to lamination was made; a new drying method "double side drying" which could avoid composition gradient was proposed . The sinter curve was made according to the TG analysis of green tape; the black alumina fabricated by the optimized process has good dimension precision.The alumina sintering temperature could reduce by adding proper flux. Alumina added...