Low dielectric constant FLARE 2.0 films as bottom antireflective coating layers for ArF lithography

We demonstrate a new bottom antireflective coating (BARC) layer for ArF lithography. The antireflective layers are composed of a low dielectric constant FLARE 2.0 film and its etching hard mask layer, such as oxide or nitride. By adding an optimized thin oxide or nitride layer, the reflectance of less than 1% at resist / silicon substrate interface can be achieved. The swing effect in the resist is also shown significantly reduced. It also has a great potential to be used as BARC layer on other highly reflectance substrate such as copper, aluminum, tungsten, titanium nitride, and tantalum nitride, which are commonly used in metal interconnect. Since it is easy to reduce reflectance by adding a FLARE film and its etching hard mask layer without adding an extra BARC layer. It is convenient to use this structure for patterning low dielectric materials in ArF lithography. Suitable etching characteristics and thermal stability of FLARE 2.0 based BARC layers are also shown in this paper.