The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 11, 1994
Filed:
Sep. 01, 1992
Hiroki Nagai, Osaka, JP;
Shigeru Yamamoto, Kyoto, JP;
Nippon Electric Glass Co., Ltd., Otsu, JP;
Abstract
In a borosilicate glass plate containing Li.sub.2 O, Na.sub.2 O and K.sub.2 O and for use as a window plate in an alumina package for containing a semiconductor device, Li.sup.+ and Na.sup.+ ions are partially ion-exchanged by K.sup.+ ions in a surface of the glass plate to form a surface layer having a compressive stress of 200 Kg.f/cm.sup.2 or more, in order to make a thin window glass plate for the package having a thickness of 0.7 mm or less and a sufficient mechanical strength. The glass also has a thermal expansion coefficient of 50-75.times.10.sup.-7 /.degree. C. over a temperature range of 30.degree.-380.degree. C. so as to be thermally compatible with the alumina package. The glass consists essentially of SiO.sub.2 55-64%, Al.sub.2 O.sub.3 7-20%, B.sub.2 O.sub.3 11-19%, Li.sub.2 O 0-8%, Na.sub.2 O 7-20%, K.sub.2 O 0-4%, and RO 0.5-7% on the base of weight percent, where R is at least one of Mg, Ca, Sr, and Ba. In order to insure the ion exchange, amounts of Li.sub.2 O, Na.sub.2 O and K.sub.2 O are adjusted so that (Li.sub.2 O+Na.sub.2 O/(Li.sub.2 O+Na.sub.2 O+K.sub.2 O) is 0.7 or more.