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:
Sep. 04, 2001
Filed:
Dec. 23, 1997
Timothy C. Krywanczyk, Essex Junction, VT (US);
Lawrence D. David, Dover, NH (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A ferric nitrate-alumina based slurry useful for Chemical-Mechanical-Polishing of tungsten metallurgy on semiconductor substrates in which the suspension and stability of abrasive material in the slurry is essentially stable. The slurry formulation is balanced to provide low residue of foreign material after polishing and due to its reduced ferric nitrate concentration will be less corrosive than prior art slurries. The recipe for the slurry includes 375 ml of a 9% wt alumina suspension, about 200 grams ferric nonahydrate, water to dilute to about 4.5 liters and enough 70% wt nitric acid to adjust the pH of the slurry to about 1.0 to 1.5.