During pattern transfer to a film stack, the hard mask layer, such as a
tunable etch resistant antireflective coating (TERA), is consumed when
etching the underling layer(s), leading to reduced etch performance and
potential damage to the underlying layer(s), such as lack of profile
control. A method of and system for preparing a structure on a substrate
is described comprising: preparing a film stack comprising a thin film, a
hard mask formed on the thin film, and a layer of light-sensitive
material formed on the hardmask; forming a pattern in the layer of
light-sensitive material; transferring the pattern to the hard mask;
removing the layer of light-sensitive material; treating the surface
layer of the hard mask in order to modify the surface; and transferring
the pattern to the thin film.