Abstract: A method for forming a tantalum-based anti-reflective coating (ARC) layer begins by forming an MOS metallic gate electrode layer (20) over a substrate (20). The MOS metallic gate electrode layer (20) is covered with an ARC layer (22). The ARC layer is preferably tantalum pentoxide or a tantalum pentoxide layer doped with one or more of nitrogen atoms and/or silicon atoms. The layers (22 and 20) are then selectively masked photoresist (24) that is selectively exposed to deep ultraviolet (DUV) radiation (28). The ARC layer (22) improves lithographic critical dimension (CD) control of the MOS metallic gate during exposure. The final MOS metallic gate is then patterned and etched using a fluorine-chlorine-fluorine time-progressed reactive ion etch (RIE) process, whereby metallic-gate MOS transistors are eventually formed.