Tape Casting Of 95 Alumina Substrates

Alumina ceramics, as one of the important advanced ceramic materials, has been widely used in many fields owing to its many excellent properties such as high-strength, high-temperature-resistant, good attrition and high resistance, and so on. The main intention of this study is to investigate 95 alumina substrates by tape casting process, which will be used as ceramic packages in kinds of integrate circuit (IC). High bending strength and fine surface were required as the basic properties of ceramic substrates. In this thesis, based on the research of the tape casting used in ceramic substrates at home and abroad. not only the processes of tape casting, but also the material selection, prepare procession and properties of 95 Al2O3 ceramics have been investigated.In the process of making 95 alumina ceramics, selected five kinds of alumina powder and studied the influence of different alumina powder on the sintering properties and mechanic properties of 95 alumina ceramics, moreover, selected the most agreeable alumina powder according to the apparatus for granularity analysis and scanning electron microscope (SEM). The influence of different sintering temperature on the sintering mechanic properties, the microstructure of 95 alumina ceramics were investigated by adding Y2O3 and La2O3 as two kinds of rare earth additives in alumina ceramics. The results indicated that the additive of La2O3 could improve the properties of 95 alumina ceramics more effectively and could get fine grain and tabular alumina that can enhance the strength of the material. The best sintering temperature range: 1570~1600℃ were selected through analyzed the relationship between sintering temperature and sintering properties. By optimizing the process parameters, 1L prescription was decided to use in tape casting process.In tape casting process, the mixture of xylene and propanol were used as the solvent of the slurry. The more suitable dispersing agent-S80 was selected as the suitable dispersing agent in the slurry to fit the solvent after the preparatory experiment. The influence of alumina powder content, the ratio of plasticizer and binder not only on the viscosity of the slurry but also on the pliability of green tape were investigated,meanwhile, the influence of the different ratio of complex plasticizer on the pliability of green tape were considered. Some conclusions obtained as follows: the best alumina content in slurry was in the range of 64~68% which was decided by the relationship between viscosity and alumina poder content in slurry. when the ratio of plasticizer and binder were in the range 0.5~0.7 with viscosity in the range from 1100 to 3500mPa·s could gain preferable slurry used in tape casting through analyzing the influence of the ratio of plasticizer and binder on viscosity. When the ratio of complex plasticizer was 1.3:1, well green tape with perfect pliability were gained. When the green tape was sintered at 1600℃, could get alumina substrates with average grain size less tan 5μm and the alumina substrates density was about 3.643g/cm3.