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:
Nov. 04, 1997
Filed:
Jun. 05, 1995
Deborah P Partlow, Pittsburgh, PA (US);
Stephen R Gurkovich, Penn Hills, PA (US);
Kenneth C Radford, North Huntingdon, PA (US);
Andrew J Piloto, Columbia, MD (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A method for forming a low temperature cofired ceramic package which is made using a multi-layered densified spherical powder formed via a sol-gel process. This densified powder is formed from layers of SiO.sub.2 reacted with trimethyl borate. The spherical powder has a preselected particle size and boron content sufficient to render the low temperature cofired ceramic package fully dense, even in the presence of a second phase filler ceramic, at a sintering temperature below 1000.degree. C. Binder material is added to the spherical powder and ceramic filler to form a plurality of tapes. A ceramic assembly is then formed by layering the plurality of tapes upon one another and firing the ceramic assembly at a temperature below 1025.degree. C. to form a fully dense cofired ceramic package. In order to form the multi-layered densified spherical powder, a silica core, which is formed using a sol-gel process, is reacted with trimethyl borate. An additional layer of silica is provided upon the reacted product which, in turn, is reacted with trimethyl borate. This process is continued until a spherical powder of desired size is formed.