Method for etching transistor gates using a hardmask
AssigneeApplied Materials, Inc.
InventorsAjay Kumar, Jeffrey Chinn, Shashank C. Deshmukh, Weinan Jiang, Rolf Adolf Guenther, Bruce Minaee, Mark Wiltse
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Abstract
An etchant composition of nitrogen trifluoride and chlorine, preferably also including a passivation material such as hydrogen bromide, etches tungsten silicide-polysilicon gate layers with high selectivity to a thin underlying silicon oxide gate oxide layer to form straight wall, perpendicular profiles with low microloading and excellent profile control.
Claims5
An etch composition for etching transistor gates on a silicon oxide layer comprising a layer of tungsten silicide over a layer of polysilicon adjacent to said silicon oxide layer, using a silicon oxide hardmask, comprising a mixture of nitrogen trifluoride, hydrogen bromide and chlorine.
A method of etching transistor gates comprising sequential layers of gate oxide, polysilicon and tungsten silicide on a substrate and using a patterned silicon oxide layer as a hardmask comprising etching the tungsten silicide and polysilicon layers with an etchant composition including nitrogen trifluoride, hydrogen bromide and chlorine.
Dependencies are inferred from the claim text.