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. 30, 2001
Filed:
Jun. 30, 1999
Raymond Thomas Galasco, Vestal, NY (US);
Lawrence Philip Lehman, Endicott, NY (US);
Roy Harvey Magnuson, Endicott, NY (US);
Robert David Topa, Binghamton, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for cleaning a copper-INVAR-copper laminate in an acid solution without inducing a galvanic etching of the INVAR. An initial step of the method forms a circuit element that includes a power supply, the laminate electrically coupled to a negative terminal of the power supply, and a conductive anode electrically coupled to a positive terminal of the power supply. The conductive anode may include a conductive material, such as titanium, that is preferably inert to an acid solution into which the laminate will be subsequently immersed. After turning on the power supply to a voltage between about 1 volts and about 10 volts, the laminate and conductive anode are immersed in the acid solution, so as to form a closed circuit with a voltage bias across acid copper-INVAR-copper interfaces. The voltage bias prevents galvanic action from occurring and therefore protects against galvanic etching of the INVAR. After the laminate has been cleaned by the acid solution, the laminate is removed from the acid solution and the power supply is turned off. The laminate may also exist as an internal layer of a dielectric substrate, wherein the substrate is immersed in the acid solution, and wherein a through hole passing through the substrate passes through the copper-INVAR-copper laminate.