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:
Oct. 18, 2005
Filed:
Jun. 28, 2004
William Y. Hata, Saratoga, CA (US);
Christopher J. Pass, San Jose, CA (US);
William Y. Hata, Saratoga, CA (US);
Christopher J. Pass, San Jose, CA (US);
Altera Corporation, San Jose, CA (US);
Abstract
An electronic package is disclosed with an underfill with multiple areas of different stiffness and a method of constructing same. An underfill shell region that contacts the chip and the substrate is stiffer than an underfill build region that does not contact either the chip or the substrate. The variation in stiffness may be achieved using materials in the shell that include more filler and/or less solvents than the materials in the bulk region. The underfill may also be composed of a single material with an adhesion to the chip and substrate that is stronger than the material's internal cohesion (e.g., a long chain polymer with an active carboxyl group at the end of the chain). This can be achieved by exposing the chip and substrate surfaces to a curing substance (e.g., vaporized hydrofluoric acid).