Novellus Systems Assigned Patent
(Targeted News Service Via Acquire Media NewsEdge) By Targeted News Service
ALEXANDRIA, Va., Feb. 16 -- Novellus Systems, San Jose, Calif., has been assigned a patent (8,372,757) developed by Steven T. Mayer, Lake Oswego, Ore., Eric Webb, Tigard, Ore., and David W. Porter, Sherwood, Ore., for a "wet etching methods for copper removal and planarization in semiconductor processing."
The abstract of the patent published by the U.S. Patent and Trademark Office states: "Exposed copper regions on a semiconductor substrate can be etched by a wet etching solution comprising (i) one or more complexing agents selected from the group consisting of bidentate, tridentate, and quadridentate complexing agents; and (ii) an oxidizer, at a pH of between about 5 and 12. In many embodiments, the etching is substantially isotropic and occurs without visible formation of insoluble species on the surface of copper. The etching is useful in a number of processes in semiconductor fabrication, including for partial or complete removal of copper overburden, for planarization of copper surfaces, and for forming recesses in copper-filled damascene features. Examples of suitable etching solutions include solutions comprising a diamine (e.g., ethylenediamine) and/or a triamine (e.g., diethylenetriamine) as bidentate and tridentate complexing agents respectively and hydrogen peroxide as an oxidizer. In some embodiments, the etching solutions further include pH adjustors, such as sulfuric acid, aminoacids, and carboxylic acids."
The patent application was filed on Aug. 4, 2009 (12/535,594). The full-text of the patent can be found at http://patft.uspto.gov/netacgi/nph-Parser Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PTXT&s1=8,372,757&OS=8,372,757&RS=8,372,757
Written by Satyaban Rath; edited by Hemanta Panigrahi.
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