Low temperature sealing composition with synthetic zircon

摘要

A sealing composition suitable for sealing alumina packages for integrated circuits at a temperature below about 450 DEG C. for a short time of about 10 minutes. The composition is a mixture of 50-80 wt % vitreous PbO-B2O3 solder glass powder having a deformation point of 350 DEG C. or less, 0-45 wt % low thermal expansion ceramic powder and 2-40 wt % zircon powder. The zircon powder is of a synthetic zircon artificially prepared to eliminate radioactive impurities such as uranium and/or thorium and contains 0.5-7 wt % Fe2O3, MnO and/or ZnO without alkali impurities and without non-reacted zirconium oxide. The composition has an improved flowability.