Native oxide removal with fluorinated chemistry before cobalt silicide formation using nitride spacers
AssigneeAdvanced Micro Devices, Inc.
InventorsJeffrey A. Shields, Bharath Rangarajan
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Abstract
A native oxide removal process utilizes a fluorinated plasma used in a sputter etch in order to remove the native oxide prior to a cobalt oxide formation process is initiated. The fluorinated plasma, such as CF4, is performed at between 50 to 100 volts bias on a substrate on which the native oxide is to be removed, and is performed in-situ. The fluorinated plasma provides both a chemical and a physical etching of the native oxide, without harming a gate oxide layer. The substrate is formed with nitride spacers and not oxide spacers, in order to lessen the possibility of any oxide being resputtered into the region in which the native oxide layer is being removed.
Claims1
An oxide removal method for a semiconductor substrate that has a native oxide layer formed thereon and nitride spacers formed adjacent to polysilicon stacks that correspond to gate regions of a transistor to be formed on the substrate, the method comprising:
- performing a sputter etch using a fluorinated plasma to remove the native oxide layer from the substrate,
- wherein no bias is provided on the substrate during the sputter etch.
Dependencies are inferred from the claim text.