Sealing glass compositions

Claim 1

In a sealing glass composition, used for sealing an alumina package containing a semiconductor integrated circuit, consisting essentially of low melting glass powder and refractory filler powder of low coefficient of thermal expansion, the improvement wherein said low melting glass has a composition consisting essentially of by weight %: ______________________________________ PbO 77.0-86.0 B.sub.2 O.sub.3 6.0-15.0 ZnO 0.5-6.9 SiO.sub.2 0.1-3.0 Al.sub.2 O.sub.3 0-3.0 MgO, CaO, BaO, SrO 0-2.0 SnO.sub.2 0-1.5 Li.sub.2 O, Na.sub.2 O, K.sub.2 O 0-1.0 ______________________________________ wherein said refractory filler is cordierite in a proportion of 2-30% by weight of the total composition and optionally, β-eucryptite, β-spodumene, lead titanate or zircon in a proportion, respectively, not exceeding 15% by weight of the total composition wherein said sealing glass composition can achieve a matched seal to a material having a thermal expansion coefficient of 65-70×10 -7 ° C. -1 (25°-400° C.) at a non-devitrified state by a heat-treatment at a temperature between 400° C. and 430° C. within a period of 10 minutes and wherein the weight loss of the composition, heat-treated at 400° to 430° C. for 10 minutes, is less than 100 mg/cm 2 when dipped in 5 wt. % nitric acid or 20 wt. % acetic acid for 10 minutes at 25° C.