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:
Jul. 16, 2002
Filed:
Jun. 14, 2001
Bernd K. Appelt, Brackney, PA (US);
Gary A. Johansson, Hockessin, DE (US);
Gerald W. Jones, Apalachin, NY (US);
Luis J. Matienzo, Endicott, NY (US);
Yenloan H. Nguyen, Binghamton, NY (US);
Konstantinos I. Papathomas, Endicott, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and structure is provided for preventing wetting or bleed of an adhesive, such as an epoxy, onto noble metal wire bond pads on the surface of a dielectric substrate when attaching an I/C chip to the substrate. The method includes treating the wire bond pads with a chemical composition which prevents bleeding onto the surfaces of the wire bond pads by a component of the epoxy. The chemical composition is a chemical which will provide “Self-Assembled Monolayers” (SAMs) on the surface of the gold. These compositions are characterized by a molecule having at least one group, such as a mercaptan or disulfide, connected to a hydrocarbon moiety, such as a (CH ) chain. The affinity of the thiol or sulfur-containing portion of the molecule chemically bonding with the noble metal provides a relatively strong attachment of the molecule to the metal surface. The hydrocarbon segment presents a surface on the noble metal that has the characteristics of the hydrocarbon portion of the molecule which has a low surface tension, and, thus, prevents wetting of the noble metal by an epoxy adhesive component. The SAMs, once they provide protection from the bleed of the die attach adhesives, self desorb during the wire bonding or soldering temperatures.