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:
Apr. 21, 2009
Filed:
Oct. 22, 2007
Denis Shamiryan, Leuven, BE;
Marc Demand, Saint-Jean-Geest, BE;
Vasile Paraschiv, Kessel-lo, BE;
Interuniversitair Microelektronica Centrum (IMEC), Leuven, BE;
Abstract
A method is disclosed for the selective removal of rare earth based high-k materials such as rare earth scandate high-k materials (e.g. DyScO) over silicon or silicon dioxide. As an example Dy and Sc comprising high-k materials are used as a high-k material in gate stacks of a semiconductor device. The selective removal and etch of this high-k material is very difficult since Dy and Sc (and their oxides) are difficult to etch. The etching could however be easily stopped on them. For patterning of the metal gates comprising TiN and TaN on top of rare earth based high-k layer a chlorine-containing gases (Cland BCl) can be used since titanium ant tantalum chlorides are volatile and reasonable selectivity to other material present on the wafer (Si, SiO) can be obtained. The Dy and Sc chlorides are not volatile, but they are water soluble. This behavior makes it possible that the surface layer of Dy and Sc comprising high-k materials gets chlorinated (brominated) during exposure to the Cl or Br comprising plasma and can be removed after etch by a water rinse.