Alumina substrate and method of manufacturing same

摘要

An improved alumina substrate comprising alumina and magnesium oxide has a surface finish of no more than 0.05 mu m CLA and a density of at least 3.90 g/cm3 in an as-fired condition and is composed of alumina grains which are sufficiently grown to have straight grain boundaries and flat surfaces to form a surface of the substrate. The improved substrate is produced by firing a green sheet having a high content of raw material powder and a density of more than 2.60 g/cm3 at a temperature of 1525 DEG to 1650 DEG C. The green sheet with high density is formed by the process of aggregating an organic agent and a high purity alumina powder by dry milling and casting the resultant slip.