THIN PLATE TYPE BOROSILICATE GLASS FOR ALUMINA PACKAGE

摘要

PURPOSE:To obtain borosilicate glass containing alkali metal oxide which is suitable for sealing and has high strength though it is thin, by making the coefft. of thermal expansion of this glass near to that of alumina and providing surface compression stress of a specified value or higher by chemical reinforcing method. CONSTITUTION:The borosilicate glass of this invention has the coefft. of thermal expansion of (50-75)X10<-7>/ deg.C in 30-380 deg.C temp. range and >=200kg f/cm<2> surface compression stress. This compressive stress is caused by exchange of one or more kinds of metal ions of the alkali metal oxides with other alkali metal ions having larger ion diameter. This borosilicate glass is sealable with alumina and has enough strength even when the glass is <=0.7mm thick. Thus, high reliability of alumina packages can be maintained.