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:
May. 22, 2001
Filed:
Feb. 28, 2000
William E. Donges, Wellington, OH (US);
Nordson Corporation, Westlake, OH (US);
Abstract
A method for attaching a semiconductor die or flip chip to a substrate to form a printed circuit board. A dispensing apparatus is spaced away from a substrate so that the dispenser does not contact the substrate. Droplets of no-flow flux and underfill material are dispensed from the dispensing apparatus onto a substrate. A flip chip with an array of solder balls or bumps on its underside is push through the material until it contacts the substrate. The flip chip and the substrate are heated sufficiently to form mechanical and electrical connections therebetween. The method of the present invention can apply the no-flow flux and underfill material in a predetermined pattern. Furthermore, the predetermined pattern of droplets can be tailored to also include a desired topography. That is, the height of the no-flow flux and underfill material can vary relative to the substantially flat surface of the substrate.